HTTPbis Working Group                                            R. Peon
Internet-Draft                                               Google, Inc
Intended status: Informational                                H. Ruellan
Expires: February 28, April 24, 2014                                        Canon CRF
                                                         August 27,
                                                        October 21, 2013

                HPACK - Header Compression for HTTP/2.0
                draft-ietf-httpbis-header-compression-03
                draft-ietf-httpbis-header-compression-04

Abstract

   This document describes HPACK, a format adapted to efficiently
   represent HTTP headers header fields in the context of HTTP/2.0.

Editorial Note (To be removed by RFC Editor)

   Discussion of this draft takes place on the HTTPBIS working group
   mailing list (ietf-http-wg@w3.org), which is archived at
   <http://lists.w3.org/Archives/Public/ietf-http-wg/>.

   Working Group information and related documents can be found at
   <http://tools.ietf.org/wg/httpbis/> (Wiki) and
   <https://github.com/http2/http2-spec> (source code and issues
   tracker).

   The changes in this draft are summarized in Appendix A.1.

Status of This Memo

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   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3  4
   2.  Overview . . . . . . . . . . . . . . . . . . . . . . . . . . .  3  4
     2.1.  Outline  . . . . . . . . . . . . . . . . . . . . . . . . .  3  4
   3.  Header Field Encoding  . . . . . . . . . . . . . . . . . . . . . . .  3  5
     3.1.  Encoding Concepts  . . . . . . . . . . . . . . . . . . . .  3  5
       3.1.1.  Encoding Context . . . . . . . . . . . . . . . . . . .  4  5
       3.1.2.  Header Table . . . . . . . . . . . . . . . . . . . . .  4  6
       3.1.3.  Reference Set  . . . . . . . . . . . . . . . . . . . .  5  6
       3.1.4.  Header set Field Representation  . . . . . . . . . . . . .  7
       3.1.5.  Header Field Emission  . . . . . . . . .  6
       3.1.5.  Header Representation . . . . . . .  8
     3.2.  Header Block Decoding  . . . . . . . . .  6
       3.1.6.  Header Emission . . . . . . . . .  8
       3.2.1.  Header Field Representation Processing . . . . . . . .  8
       3.2.2.  Reference Set Emission . . .  6
     3.2.  Header Set Processing . . . . . . . . . . . . .  9
       3.2.3.  Header Set Completion  . . . . .  7
       3.2.1.  Header Representation Processing . . . . . . . . . . .  7
       3.2.2.  Reference Set Emission  9
     3.3.  Header Table Management  . . . . . . . . . . . . . . . .  7
       3.2.3.  Header Set Completion .  9
       3.3.1.  Maximum Table Size . . . . . . . . . . . . . . .  8
       3.2.4.  Header Table Management . . .  9
       3.3.2.  Entry Eviction When Header Table Size Changes  . . . . 10
       3.3.3.  Entry Eviction when Adding New Entries . . . . . . . .  8 10
   4.  Detailed Format  . . . . . . . . . . . . . . . . . . . . . . .  8 10
     4.1.  Low-level representations  . . . . . . . . . . . . . . . .  8 10
       4.1.1.  Integer representation . . . . . . . . . . . . . . . .  8 11
       4.1.2.  Header Name Representation . . . . . . . . . . . . . . 10
       4.1.3.  Header Value  String Literal Representation  . . . . . . . . . . . . . 11 13
     4.2.  Indexed Header Field Representation  . . . . . . . . . . . . . . 11 14
     4.3.  Literal Header Field Representation  . . . . . . . . . . . . . . 11 15
       4.3.1.  Literal Header Field without Indexing  . . . . . . . . . . . 11 15
       4.3.2.  Literal Header Field with Incremental Indexing . . . . 16
   5.  Security Considerations  . . . 12
       4.3.3.  Literal Header with Substitution Indexing . . . . . . 13
   5.  Parameter Negotiation . . . . . . . . . . 17
   6.  References . . . . . . . . . . 15
   6.  Security Considerations . . . . . . . . . . . . . . . . 18
     6.1.  Normative References . . . 15
   7.  IANA Considerations . . . . . . . . . . . . . . . . 18
     6.2.  Informative References . . . . . 16
   8.  References . . . . . . . . . . . . . 18
   Appendix A.  Change Log (to be removed by RFC Editor before
                publication . . . . . . . . . . . . . 16
     8.1.  Normative References . . . . . . . . 19
     A.1.  Since draft-ietf-httpbis-header-compression-03 . . . . . . 19
     A.2.  Since draft-ietf-httpbis-header-compression-02 . . . . . 16
     8.2.  Informative References . 19
     A.3.  Since draft-ietf-httpbis-header-compression-01 . . . . . . 19
     A.4.  Since draft-ietf-httpbis-header-compression-01 . . . . . . 19
   Appendix B.  Static Table  . . . . . 16
   Appendix A.  Change Log (to be removed by RFC Editor before
                publication . . . . . . . . . . . . . . . . . . . . . 17
     A.1.  Since draft-ietf-httpbis-header-compression-01 . . . . . . 17
     A.2.  Since draft-ietf-httpbis-header-compression-01 . . . . . . 17 20
   Appendix B.  Initial Header Tables . . . . . . . . . . . . . . . . 18
     B.1. C.  Huffman Codes For Requests  . . . . . . . . . . . . . . . . . . . . . . . . . 18
     B.2. 22
   Appendix D.  Huffman Codes for Responses . . . . . . . . . . . . . . . . . . . . . . . . 19 28
   Appendix C.  Example E.  Examples  . . . . . . . . . . . . . . . . . . . . . . . 20
     C.1.  First header set . . . . 33
     E.1.  Request Decoding Example With Huffman  . . . . . . . . . . 33
     E.2.  Request Decoding Example Without Huffman . . . . . . . 20
     C.2.  Second header set . . 38
     E.3.  Response Decoding Example With Huffman . . . . . . . . . . 43
     E.4.  Response Decoding Example Without Huffman  . . . . . . . . 22 51

1.  Introduction

   This document describes HPACK, a format adapted to efficiently
   represent HTTP headers header fields in the context of HTTP/2.0. HTTP/2.0 (see
   [HTTP2]).

2.  Overview

   In HTTP/1.X, headers HTTP/1.X (see [HTTP-p1]), header fields are sent without any form
   of compression.  As web pages have grown to include dozens to
   hundreds of requests, the redundant headers header fields in these requests
   now pose a problem of measurable latency and unnecessary bandwidth. 1 bandwidth
   (see [PERF1] 2 [PERF2] and [PERF2]).

   SPDY [SPDY] initially addressed this redundancy by compressing
   headers header
   fields with Deflate, which proved very effective at eliminating the
   redundant headers. header fields.  However, that aproach exposed a security
   risk as demonstrated by the CRIME [CRIME].

   In this document, we propose a new header compressor for header fields which
   eliminates
   the redundant headers, header fields, is not vulnerable to the CRIME style attack,
   attacks, and which also has a bounded memory cost for use in small
   constrained environments.

2.1.  Outline

   The HTTP header field encoding described in this document is based on
   a header table that map (name, value) pairs to index values.  Header
   tables are incrementally updated during the HTTP/2.0 session.

   The encoder is responsible for deciding which headers header fields to insert
   as new entries in the header table.  The decoder then does exactly
   what the encoder prescribes, ending in a state that exactly matches
   the encoder's state.  This enables decoders to remain simple and
   understand a wide variety of encoders.

   As two consecutive sets of headers header fields often have headers header fields in
   common, each set of headers header fields is coded as a difference from the
   previous set of
   headers. header fields.  The goal is to only encode the
   changes (headers (header fields present in one of the set and not in the
   other) between the two sets of headers.

   An example header fields.

   Examples illustrating the use of these different mechanisms to
   represent headers is header fields are available in Appendix C. E.

3.  Header Field Encoding

3.1.  Encoding Concepts

   The encoding and decoding of headers header fields relies on some components
   and
   concepts.  The set concepts:

   Header Field:  A key, value pair.  HPACK allows a header field value
      to be either a value as specified by HTTP/1.X (see [HTTP-p1]), or
      a NULL-separated ordered list of components used form an encoding context. HTTP/1.X values.

   Header Table:  The header table (see Section 3.1.2) is a component
      used to associate headers stored header fields to index values.  The data
      stored in this table is in first-in, first-out order.

   Static Table:  The static table (see Appendix B) is a component used
      to associate static header fields to index values.  This data is
      ordered, read-only, always accessible, and may be shared amongst
      all encoding contexts.

   Reference Set:  The reference set (see Section 3.1.3) is a component
      containing a group an unordered set of headers references to entries in the header
      table or static table.  This is used as a reference for the differential encoding
      of a new set of headers. header set.

   Header Set:  A header set (see Section 3.1.4) is a potentially ordered group of headers header
      fields that are encoded jointly.  A complete set of key-value
      pairs as
      encoded contained in an a HTTP request or response is a header set.

   Header Field Representation:  A header field can be represented in
      encoded form either as a literal or as an index (see
      Section 3.1.5). 3.1.4).

   Header Block:  The
      indexed representation is based on the entire set of encoded header table. field representations
      which, when decoded, yield a complete header set.

   Header Field Emission:  When decoding a set of headers, header field
      representations, some operations emit a header field (see
      Section 3.1.6).  An emitted header is added to
      the set of 3.1.5).  Emitted headers that form the HTTP request or response.  Once
      emitted, a header can't can be removed from safely passed to the set upper
      processing layers as part of headers. the current Header Set.

3.1.1.  Encoding Context

   The set of components mutable structures used to encode or decode a header set form an
   encoding context: within an encoding context contains include
   a header table and a reference set.  Everything else is either
   immutable or conceptual.

   Using HTTP, messages are exchanged between a client and a server in
   both direction.  To keep the encoding of headers header fields in each
   direction independent from the other direction, there is one encoding
   context for each direction.

   The headers header fields contained in a PUSH_PROMISE frame sent by a server
   to a client are encoded within the same context as the headers header fields
   contained in the HEADERS frame corresponding to a response sent from
   the server to the client.

3.1.2.  Header Table

   A header table consists of an ordered a list of (name, value) pairs. header fields maintained in
   first-in, first-out order.  The first and newest entry of in a header
   table is assigned the always at index 0.

   A header can be represented by an entry from the header table.
   Rather than encoding a literal value for the header field name 0, and
   value, the encoder can select an oldest entry from the header table.

   Literal of a header names MUST be translated to lowercase before encoding
   and transmission.  This enables an encoder to perform direct bitwise
   comparisons on names and values when determining if an entry already
   exists in table is
   at the index len(header table)-1.

   The header table. table is initially empty.

   There is typically no need for the header table to contain duplicate
   entries.  However, duplicate entries MUST NOT be treated as an error
   by a decoder.

   Initially, a header table contains a list of common headers.  Two
   initial lists of header are provided in Appendix B.  One list is for
   headers transmitted from a client to a server, the other for the
   reverse direction.

   A header table is modified by either adding a new entry at the end of
   the table, or by replacing an existing entry.

   The encoder decides how to update the header table and as such can
   control how much memory is used by the header table.  To limit the
   memory requirements on the decoder side, the header table size is
   strictly bounded (see the SETTINGS_HEADER_TABLE_SIZE in Section 5). 3.3.1).

   The size of an entry header table is updated during the sum of its name's length in bytes (as
   defined in Section 4.1.2), processing of its value's length in bytes
   (Section 4.1.3) and a set of 32 bytes.  The 32 bytes are an accounting for
   the entry structure overhead.  For example, an entry structure using
   two 64-bits pointers to reference the name and the value and the
   entry, and two 64-bits integer for counting the number of references
   to these name and value would use 32 bytes.

   The size of a header table is the sum of the size of its entries.
   field representations (see header field representation processing
   (Section 3.2.1).

3.1.3.  Reference Set

   A reference set is defined as an unordered set of references to entries of either
   within the header table or the static table.

   The initial reference set is the empty set. initially empty.

   The reference set is updated during the processing of a set of
   headers.

   Using the header
   field representations (see header field representation processing
   (Section 3.2.1).

   The reference set enables differential encoding, a whereby only
   differences between the previous header that is not present in set and the
   reference current header
   set can need to be encoded either with encoded.

   When an indexed representation
   (if the header entry is present in the header table), or with a literal
   representation (if evicted from the header is not present in table, if it was referenced
   from the header table).

   A header that reference set, its reference is to be removed from the reference set is encoded with
   an indexed representation.
   set.

3.1.4.  Header set

   A header set is a group of header fields that are Field Representation

   An encoded as a whole.
   Each header field is a (name, value) pair.

   A header set is encoded using an ordered list of zero or more header
   representations.  All the header representations describing a header
   set a grouped into a header block.

3.1.5.  Header Representation

   A header can be represented either as a literal or as
   an index.

   Literal Representation:  A literal representation defines a new
      header.
      header field.  The header field name is represented either
      literally or as a reference to an entry of the header table.  The
      header field value is represented literally.

      Three

      Two different literal representations are provided:

      *  A literal representation that does not add the header field to
         the header table (see Section 4.3.1).

      *  A literal representation that adds the header field as a new
         entry at the end beginning of the header table (see Section 4.3.2).

      *  A literal representation that uses the header to replace an
         existing entry of the header table (see Section 4.3.3).

   Indexed Representation:  The indexed representation defines a header
      field as a reference to an entry in either the header table (see or the
      static table(see Section 4.2).

3.1.6.

          <----------  Index Address Space ---------->
          <-- Header  Table -->  <-- Static  Table -->
          +---+-----------+---+  +---+-----------+---+
          | 0 |    ...    | k |  |k+1|    ...    | n |
          +---+-----------+---+  +---+-----------+---+
          ^                   |
          |                   V
   Insertion Point       Drop Point

                             Index Address Space

         Indices between 0 and len(header table)-1, inclusive, refer to
         elements in the header table, with index 0 referring to the
         beginning of the table.

         Indices between len(header table) and len(header table)+
         len(static table)-1, inclusive, refer to elements in the static
         table, where the index len(header table) refers to the first
         entry in the static table.

         Any other indices MUST be treated as erroneous, and the
         compression context considered corrupt and unusable.

3.1.5.  Header Field Emission

   The emission of a header field is the process of adding a passing that header
   field to the
   current set of headers.  Once an header is emitted, it can't be
   removed from application, so that the current set of headers.

   The concept of header emission allows a decoder to know when it application can
   pass a header safely process and
   react to a higher level on header field data.

   By emitting header fields instead of emitting header sets, the receiver side.  This
   allows a
   decoder to can be implemented in a streaming way, and as such to must only
   keep in memory the header table and the reference set.  With
   such an implementation,  This bounds
   the amount of memory used by the decoder is
   bounded, decoder, even in presence of a very
   large set of headers. header fields.  The management of memory for handling
   very large sets of headers header fields can therefore be deferred to the application, which may
   application.

   When a header field is a NULL-separated list of values, each value
   within the list MAY be able to emit emitted separately, with the same header to the wire field
   name, and thus free up memory quickly. the order of emission MUST be the order of appearance in
   the list.

3.2.  Header Set Processing Block Decoding

   The processing of an encoded a header set block to obtain a list of headers header set is defined in
   this section.  To ensure a correct that the decoding of will successfully produce
   a header set, a decoder MUST obey the following rules.

3.2.1.  Header Field Representation Processing

   All the header field representations contained in a header block are
   processed in the order in which they are presented, as specified
   below.

   An _indexed representation_ corresponding to an entry _not present_ _present_ in
   the reference set entails the following actions:

   o  The header corresponding reference to the entry is emitted.

   o  The entry is added to removed from the reference set.

   An _indexed representation_ corresponding to an entry _present_ _not present_
   in the reference set entails the following actions:

   o  The entry is removed from the reference set.

   A _literal representation_ that is _not added_ to the header table
   entails  If referencing an element of the following action:

   o static table:

      *  The header is emitted.

   A _literal representation_ that is _added_ field corresponding to the header table
   entails the following actions:

   o  The header referenced entry is
         emitted.

   o

      *  The header referenced static entry is added to the header table, at table.

      *  If the location defined
      by new entry fits within the representation. header table, a reference to
         the header table entry is added to the reference set.

   o  If referencing an element of the header table:

      *  The header field corresponding to the referenced entry is
         emitted.

      *  The referenced header table entry is added to the header table.

   A _literal representation_ that is _not added_ to the header table
   entails the following action:

   o  The header field is emitted.

   A _literal representation_ that is _added_ to the header table
   entails the following actions:

   o  The header field is inserted at the beginning of the header table.

   o  A reference to the new entry is added to the reference set.

   o  The header field is emitted.

3.2.2.  Reference Set Emission

   Once all the representations contained in a header block have been
   processed, the headers that are in common with the previous header
   set are emitted, during the reference set emission.

   For the reference set emission, each header contained fields referenced in the reference set that has which
   have not previously been emitted during the this processing of the
   header block is are emitted.

3.2.3.  Header Set Completion

   Once all of the header field representations have been processed, and
   the remaining items in the reference set have been emitted, the
   header set is complete.

3.2.4.

3.3.  Header Table Management

   The header table can be modified by either adding a new entry to it
   or by replacing an existing one.  Before doing such a modification,
   it has to be ensured that the header table size will stay lower than
   or equal to the SETTINGS_HEADER_TABLE_SIZE limit (see Section 5).

3.3.1.  Maximum Table Size

   To
   achieve this, repeatedly, limit the first entry of memory requirements on the header table is
   removed, until enough space is available for decoder side, the modification.

   A consequence size of removing one or more entries at the beginning of
   the header table is that the remaining entries are renumbered. bounded.  The first
   entry size of the header table is always associated MUST stay
   lower than or equal to the index 0.

   When value of the modification HTTP/2.0 setting
   SETTINGS_HEADER_TABLE_SIZE (see [HTTP2]).

   The size of the the header table is the replacement sum of an
   existing entry, the replaced size of its
   entries.

   The size of an entry is the one indicated in sum of its name's length in bytes (as
   defined in Section 4.1.2), of its value's length in bytes
   (Section 4.1.2) and of 32 bytes.

   The lengths are measured on the
   literal representation before any non-encoded entry name and entry
   value (for the case when a Huffman encoding is removed from used to transmit
   string values).

   The 32 bytes are an accounting for the header
   table.  If entry structure overhead.  For
   example, an entry structure using two 64-bits pointers to reference
   the name and the value and the entry, and two 64-bits integer for
   counting the number of references to these name and value would use
   32 bytes.

3.3.2.  Entry Eviction When Header Table Size Changes

   Whenever an entry is evicted from the header table, any reference to be replaced
   that entry contained by the reference set is removed removed.

   Whenever SETTINGS_HEADER_TABLE_SIZE is made smaller, entries are
   evicted from the end of the header table
   when performing until the size adjustment, the replacement entry is
   inserted at the beginning of the header table.
   table is less than or equal to SETTINGS_HEADER_TABLE_SIZE.

   The addition eviction of a new an entry with a size greater than from the
   SETTINGS_HEADER_TABLE_SIZE limit header table causes all the index of
   the entries from in the
   header static table to be dropped and the reduced by one.

3.3.3.  Entry Eviction when Adding New Entries

   Whenever a new entry not is to be added to the table, any name referenced
   by the representation is cached, and then entries are evicted from
   the end of the header table.  The replacement table until the size of an existing entry with a the header table is
   less than or equal to SETTINGS_HEADER_TABLE_SIZE - new entry
   with a size, or
   until the table is empty.

   If the size greater than of the SETTINGS_HEADER_TABLE_SIZE has new entry is less than or equal to
   SETTINGS_HEADER_TABLE_SIZE, that entry is added to the same
   consequences. table.  It is
   not an error to attempt to add an entry that is larger than
   SETTINGS_HEADER_TABLE_SIZE.

4.  Detailed Format

4.1.  Low-level representations
4.1.1.  Integer representation

   Integers are used to represent name indexes, pair indexes or string
   lengths.  To allow for optimized processing, an integer
   representation always finishes at the end of a byte.

   An integer is represented in two parts: a prefix that fills the
   current byte and an optional list of bytes that are used if the
   integer value does not fit in within the prefix.  The number of bits of
   the prefix (called N) is a parameter of the integer representation.

   The N-bit prefix allows filling the current byte.  If the value is
   small enough (strictly less than 2^N-1), it is encoded within the
   N-bit prefix.  Otherwise all the bits of the prefix are set to 1 and
   the value is encoded using an unsigned variable length integer [1]
   representation.

   The algorithm to represent an  N is always between 1 and 8 bits.  An integer
   starting at a byte-boundary will have an 8-bit prefix.

   The algorithm to represent an integer I is as follows:

   If I < 2^N - 1, encode I on N bits
   Else
       encode 2^N - 1 on N bits
       I = I - (2^N - 1)
       While I >= 128
            Encode (I % 128 + 128) on 8 bits
            I = I / 128
       encode (I) on 8 bits

   This integer representation allows for values of indefinite size.  It
   is also possible for an encoder to send a large number of zero
   values, which can waste bytes and could be used to overflow integer
   values.  Excessively large integer encodings - in value or octet
   length - MUST be treated as a decoding error.  Different limits can
   be set for each of the different uses of integers, based on
   implementation constraints.

4.1.1.1.  Example 1: Encoding 10 using a 5-bit prefix

   The value 10 is to be encoded with a 5-bit prefix.

   o  10 is less than 31 (= 2^5 - 1) and is represented using the 5-bit
      prefix.

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | X | X | X | 0 | 1 | 0 | 1 | 0 |   10 stored on 5 bits
   +---+---+---+---+---+---+---+---+

4.1.1.2.  Example 2: Encoding 1337 using a 5-bit prefix

   The value I=1337 is to be encoded with a 5-bit prefix.

      1337 is greater than 31 (= 2^5 - 1).

         The 5-bit prefix is filled with its max value (31).

      I = 1337 - (2^5 - 1) = 1306.

         I (1306) is greater than or equal to 128, the while loop body
         executes:

            I % 128 == 26

            26 + 128 == 154

            154 is encoded in 8 bits as: 10011010

            I is set to 10 (1306 / 128 == 10)

            I is no longer greater than or equal to 128, the while loop
            terminates.

         I, now 10, is encoded on 8 bits as: 00001010

      The process ends.

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | X | X | X | 1 | 1 | 1 | 1 | 1 |  Prefix = 31, I = 1306
   | 1 | 0 | 0 | 1 | 1 | 0 | 1 | 0 |  1306>=128, encode(154), I = 1306/128 I=1306/128
   | 0 | 0 | 0 | 0 | 1 | 0 | 1 | 0 |  10<128, encode(10), done
   +---+---+---+---+---+---+---+---+

4.1.2.  Header Name  String Literal Representation

   Header field names and header field values are encoded as sequences
   of ASCII characters that MUST conform to
   the following header-name ABNF construction:

     LOWERALPHA = %x61-7A
     header-char = "!" / "#" / "$" / "%" / "&" / "'" /
                   "*" / "+" / "-" / "." / "^" / "_" /
                   "`" / "|" / "~" / DIGIT / LOWERALPHA
     header-name = [":"] 1*header-char

   They are bytes.  A header field name or a header field value is encoded in two
   three parts:

   1.  The length of the text, defined as  One bit, H, indicating whether or not the bytes are huffman
       encoded.

   2.  The number of octets of
       storage bytes required to store hold the text, result of the next step,
       represented as a variable-
       length-quantity variable-length-quantity (Section 4.1.1).

   2. 4.1.1),
       starting with a 7-bit prefix immediately following the first bit.

   3.  The specific sequence of ASCII octets

4.1.3.  Header Value Representation

   Header values are encoded as sequences data of UTF-8 encoded text.  They
   are encoded in two parts: the string:

       1.  The length of  If H is true, then the text, defined as the number of octets of
       storage required to store encoded string data is the text, represented as a variable-
       length-quantity (Section 4.1.1).

   2.  The specific sequence bitwise
           concatenation of octets representing the UTF-8 text.

   Invalid UTF-8 octet sequences, "over-long" UTF-8 encodings, and UTF-8
   octets that represent invalid Unicode Codepoints MUST NOT be used.

4.2.  Indexed Header Representation

   An indexed header representation identifies an entry in canonical [CANON]huffman code [HUFF]
           corresponding to each character of the header
   table.  The entry data, followed by
           between 0-7 bits of padding.

       2.  If H is emitted and added to false, then the reference set if it encoded string is
   not currently in the reference set.  The entry bytes of the
           field value without modification.

   Padding is removed necessary when doing huffman encoding to ensure that the
   remaining bits between the actual end of the data and the next byte
   boundary are not misinterpreted as part of the input data.

   When padding for huffman encoding, use the bits from the
   reference set if it is present EOS (end-of-
   string) entry in the reference set.

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 1 |        Index (7+)         |
   +---+---------------------------+

                              Indexed Header Huffman table, starting with the MSB.  This representation starts
   entry is guaranteed to be at least 8 bits long.

   String literals sent in the client to server direction which use
   huffman encoding are encoded with the '1' 1-bit pattern, followed by codes within the index of request
   huffman code table (Appendix C) (see Request Decoding With Huffman
   Example (Appendix E.3)).

   String literals sent in the matching pair, server to client direction which use
   huffman encoding are encoded with the codes within the response
   huffman code table (Appendix D) (see Response Decoding With Huffman
   Example (Appendix E.3)).

   The EOS symbol is represented as an integer with a
   7-bit prefix.

4.3.  Literal Header Representation

   Literal header representations contain a literal header field value.
   Header field names are either provided as a literal or by reference value 256, and is used solely to an existing header table entry.

   Literal representations all result in
   signal the emission end of a header when
   decoded.

4.3.1.  Literal Header without Indexing

   An literal header without indexing causes the emission huffman-encoded key data or the end of a header
   without altering the header table.
   huffman-encoded value data.  Given that only between 0-7 bits of the
   EOS symbol is included in any huffman-encoded string, and given that
   the EOS symbol is at least 8 bits long, it is expected that it should
   never be successfully decoded.

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 | 1 | 1 |    Index (5+)  Value Length Prefix (7)  |
   +---+---+---+-------------------+
   +---+---+---+---+---+---+---+---+
   |   Value Length (8+) (0-N bytes)    |
   +-------------------------------+
   +---+---+---+---+---+---+---+---+
   ...
   +---+---+---+---+---+---+---+---+
   | Value Huffman Encoded Data  |Padding|
   +---+---+---+---+---+---+---+---+

                   String (Length octets)  |
   +-------------------------------+ Literal Header without Indexing - With Huffman Encoding

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 |  Value Length Prefix (7)  |
   +---+---+---+---+---+---+---+---+
   |   Value Length (0-N bytes)    |
   +---+---+---+---+---+---+---+---+
   ...
   +---+---+---+---+---+---+---+---+
   |  Field Bytes Without Encoding |
   +---+---+---+---+---+---+---+---+

                  String Literal Without Huffman Encoding

4.2.  Indexed Name Header Field Representation

   An indexed header field representation either identifies an entry in
   the header table or static table.  The specified entry is emitted and
   a reference to that entry is added to the reference set if it is not
   currently in the reference set.  If it is present in the reference
   set then the reference is removed and the entry is not emitted.

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 1 |        Index (7+)         |
   +---+---------------------------+

                           Indexed Header Field

   This representation starts with the '1' 1-bit pattern, followed by
   the index of the matching pair, represented as an integer with a
   7-bit prefix.

4.3.  Literal Header Field Representation

   Literal header field representations contain a literal header field
   value.  Header field names are either provided as a literal or by
   reference to an existing header table or static table entry.

   Literal representations all result in the emission of a header field
   when decoded.

4.3.1.  Literal Header Field without Indexing

   A literal header field without indexing causes the emission of a
   header field without altering the header table.

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 | 1 |      Index (6+)       |
   +---+---+---+-------------------+
   |       Value Length (8+)       |
   +-------------------------------+
   | Value String (Length octets)  |
   +-------------------------------+

           Literal Header Field without Indexing - Indexed Name

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 | 1 |           0           |
   +---+---+---+-------------------+
   |       Name Length (8+)        |
   +-------------------------------+
   |  Name String (Length octets)  |
   +-------------------------------+
   |       Value Length (8+)       |
   +-------------------------------+
   | Value String (Length octets)  |
   +-------------------------------+

             Literal Header Field without Indexing - New Name

   This representation starts with the '011' 3-bit '01' 2-bit pattern.

   If the header field name matches the header field name of a (name,
   value) pair stored in the Header Table or Static Table, the index of the pair
   that entry, increased by one (index + 1) 1), is represented as an
   integer with a 5-bit 6-bit prefix.  Note that if the index is strictly
   below 31, 63, only one byte is used. used for this representation.

   If the header field name does not match a header field name entry,
   the value 0 is represented on 5 6 bits followed by the header field
   name (Section 4.1.2).

   Header

   The header field name representation is followed by the header field
   value represented as a literal string as described in Section 4.1.3. 4.1.2.

4.3.2.  Literal Header Field with Incremental Indexing

   A literal header field with incremental indexing adds a new entry to
   the header table.

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 | 1 | 0 |      Index (5+) (6+)       |
   +---+---+---+-------------------+
   |       Value Length (8+)       |
   +-------------------------------+
   | Value String (Length octets)  |
   +-------------------------------+

             Literal Header Field with Incremental Indexing -
                               Indexed Name

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 | 1 | 0 |           0           |
   +---+---+---+-------------------+
   |       Name Length (8+)        |
   +-------------------------------+
   |  Name String (Length octets)  |
   +-------------------------------+
   |       Value Length (8+)       |
   +-------------------------------+
   | Value String (Length octets)  |
   +-------------------------------+

             Literal Header Field with Incremental Indexing -
                                 New Name

   This representation starts with the '010' 3-bit '00' 2-bit pattern.

   If the header field name matches the header field name of a (name,
   value) pair stored in the Header Table, header table or static table, the index of
   the pair increased by one (index + 1) is represented as an integer
   with a 5-bit 6-bit prefix.  Note
   that if the index is strictly below 31, one byte is used.

   If the header field name does not match a header field name entry,
   the value 0 is represented on 5 6 bits followed by the header field
   name (Section 4.1.2).

   Header

   The header field name representation is followed by the header field
   value represented as a literal string as described in Section 4.1.3.

4.3.3.  Literal Header with Substitution Indexing

   A literal header with substitution indexing replaces an existing
   header table entry.

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 | 0 |      Index (6+)       |
   +---+---+-----------------------+
   |    Substituted Index (8+)     |
   +-------------------------------+
   |       Value Length (8+)       |
   +-------------------------------+
   | Value String (Length octets)  |
   +-------------------------------+

                Literal Header with Substitution Indexing -
                               Indexed Name

     0   1   2   3   4   5   6   7
   +---+---+---+---+---+---+---+---+
   | 0 | 0 |           0           |
   +---+---+-----------------------+
   |       Name Length (8+)        |
   +-------------------------------+
   |  Name String (Length octets)  |
   +-------------------------------+
   |    Substituted Index (8+)     |
   +-------------------------------+
   |       Value Length (8+)       |
   +-------------------------------+
   | Value String (Length octets)  |
   +-------------------------------+

                Literal Header with Substitution Indexing -
                                 New Name 4.1.2.

5.  Security Considerations

   This representation starts with the '00' 2-bit pattern.

   If compressor exists to solve security issues present in stream
   compressors such as DEFLATE whereby the header name matches compression context can be
   efficiently probed to reveal secrets.  A conformant implementation of
   this specification should be fairly safe against that kind of attack,
   as the header name reaping of a (name, value) pair
   stored in any information from the Header Table, compression context
   requires more work than guessing and verifying the index of plaintext data
   directly with the pair increased by one
   (index + 1) is represented as an integer server.  As with a 6-bit prefix.  Note
   that if any secret, however, the index is strictly below 63, one byte is used.

   If longer
   the header name does not match a header name entry, length of the value 0 secret, the more difficult the secret is
   represented on 6 bits followed to guess.
   It is inadvisable to have short cookies that are relied upon to
   remain secret for any duration of time.

   A proper security-conscious implementation will also need to prevent
   timing attacks by ensuring that the header name (Section 4.1.2).

   The index amount of the substituted (name, value) pair time it takes to do
   string comparisons is inserted after the
   header name representation as always a 0-bit prefix integer.

   The index function of the substituted pair MUST correspond to a position in total length of the header table containing
   strings, and not a non-void entry.  An index for the
   substituted pair that corresponds to empty position in the header
   table MUST be treated as an error.

   This index is followed by function of the header value represented as a literal
   string as described in Section 4.1.3.

5.  Parameter Negotiation number of matched characters.

   A few parameters can be used decoder needs to accommodate client and server
   processing and memory requirements. [[anchor3: These settings are
   currently not supported as they have ensure that larger values or encodings of integers
   do not been integrated in the main
   specification.  Therefore, permit exploitation.  Decoders MUST limit the maximum buffer size for the header
   table is fixed at 4096 bytes.]]

   SETTINGS_HEADER_TABLE_SIZE (TBD):  Allows the sender to inform the
      remote endpoint of the maximum size
   integers, both in value and encoded length, that it accepts for the header
      table.
      The default value (see
   Section 4.1.1).

   Another common security problem is 4096 bytes.
      [[anchor4: Is this default value OK?  Do we need a maximum size?
      Do we want to allow infinite buffer?]]
      When the remote endpoint receives a SETTINGS frame containing a
      SETTINGS_HEADER_TABLE_SIZE setting with a value smaller than the
      one currently in use, it MUST send as soon as possible a HEADER
      frame with a stream identifier of 0x0 containing a value smaller
      than or equal to the received setting value.
      [[anchor5: This changes slightly the behaviour of the HEADERS
      frame, which should be updated as follows:]]
      A HEADER frame with a stream identifier of 0x0 indicates that the
      sender has reduced the maximum size of the header table.  The new
      maximum size of the header table is encoded on 32-bit.  The
      decoder MUST reduce its own header table by dropping entries from
      it until the size of the header table is lower than or equal to
      the transmitted maximum size.

6.  Security Considerations

   This compressor exists to solve security issues present in stream
   compressors such as DEFLATE whereby the compression context can be
   efficiently probed to reveal secrets.  A conformant implementation of
   this specification should be fairly safe against that kind of attack,
   as the reaping of any information from the compression context
   requires more work than guessing and verifying the plaintext data
   directly with the server.  As with any secret, however, the longer
   the length of the secret, the more difficult the secret is to guess.
   It is inadvisable to have short cookies that are relied upon to
   remain secret for any duration of time.

   A proper security-conscious implementation will also need to prevent
   timing attacks by ensuring that the amount of time it takes to do
   string comparisons is always a function of the total length of the
   strings, and not a function of the number of matched characters.

   Another common security problem is when when the remote endpoint
   successfully causes the local endpoint to exhaust its memory.  This
   compressor attempts to deal with the most obvious ways that this
   could occur by limiting both the peak and the steady-state amount of
   memory consumed in the compressor state, by providing ways for the
   application to consume/flush the emitted headers in header fields in small
   chunks, and by considering overhead in the state size calculation.
   Implementors must still be careful in the creation of APIs to an
   implementation of this compressor by ensuring that header field keys
   and values are either emitted as a stream, or that the compression
   implementation have a limit on the maximum size of a key or value.
   Failure to implement these kinds of safeguards may still result in a
   scenario where the local endpoint exhausts its memory.

7.  IANA Considerations

   This document registers the SETTINGS_HEADER_TABLE_SIZE setting in the
   "HTTP/2.0 Settings" registry established by [HTTP2].  The assigned
   code for this setting is TBD.

8.

6.  References

8.1.
6.1.  Normative References

   [HTTP-p1]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              draft-ietf-httpbis-p1-messaging-24 (work in progress),
              September 2013.

   [HTTP2]    Belshe, M., Peon, R., Thomson, M., and A. Melnikov,
              "Hypertext Transfer Protocol version 2.0",
              draft-ietf-httpbis-http2-06 (work in progress),
            February
              August 2013.

8.2.

6.2.  Informative References

   [CANON]    Schwartz, E. and B. Kallick, "Generating a canonical
              prefix encoding", Communications of the ACM Volume 7 Issue
              3, pp. 166-169, March 1964,
              <http://dl.acm.org/citation.cfm?id=363991>.

   [CRIME]    Rizzo, J. and T. Duong, "The Crime Attack",
              September 2012,
            <https://docs.google.com/a/twist.com/presentation/d/ <https://docs.google.com/a/twist.com/
              presentation/d/
              11eBmGiHbYcHR9gL5nDyZChu_-lCa2GizeuOfaLU2HOU/
              edit#slide=id.g1eb6c1b5_3_6>.

   [HUFF]     Huffman, D., "A Method for the Construction of Minimim
              Redundancy Codes", Proceedings of the Institute of Radio
              Engineers Volume 40, Number 9, pp. 1098-1101,
              September 1952, <http://ieeexplore.ieee.org/xpl/
              articleDetails.jsp?arnumber=4051119>.

   [PERF1]    Belshe, M., "IETF83: SPDY and What to Consider for
              HTTP/2.0", March 2012, <http://www.ietf.org/proceedings/83/
            slides/slides-83-httpbis-3>. <http://www.ietf.org/proceedings/
              83/slides/slides-83-httpbis-3>.

   [PERF2]    McManus, P., "SPDY "SPDY: What I Like About You",
              September 2011, <
            http://bitsup.blogspot.com/2011/09/ <http://bitsup.blogspot.com/2011/09/
              spdy-what-i-like-about-you.html>.

   [SPDY]     Belshe, M. and R. Peon, "SPDY Protocol",
              draft-mbelshe-httpbis-spdy-00 (work in progress),
              February 2012,
            <http://tools.ietf.org/html/draft-mbelshe-httpbis-spdy>. 2012.

URIs

   [1]  <http://en.wikipedia.org/wiki/Variable-length_quantity>

Appendix A.  Change Log (to be removed by RFC Editor before publication

A.1.  Since draft-ietf-httpbis-header-compression-03

   o  A large number of editorial changes; changed the description of
      evicting/adding new entries.

   o  Removed substitution indexing

   o  Changed 'initial headers' to 'static headers', as per issue #258

   o  Merged 'request' and 'response' static headers, as per issue #259

   o  Changed text to indicate that new headers are added at index 0 and
      expire from the largest index, as per issue #233

A.2.  Since draft-ietf-httpbis-header-compression-02

   o  Corrected error in integer encoding pseudocode.

A.3.  Since draft-ietf-httpbis-header-compression-01

   o  Refactored of Header Encoding Section: split definitions and
      processing rule.

   o  Backward incompatible change: Updated reference set management as
      per issue #214.  This changes how the interaction between the
      reference set and eviction works.  This also changes the working
      of the reference set in some specific cases.

   o  Backward incompatible change: modified initial header list, as per
      issue #188.

   o  Added example of 32 bytes entry structure (issue #191).

   o  Added Header Set Completion section.  Reflowed some text.
      Clarified some writing which was akward.  Added text about
      duplicate header entry encoding.  Clarified some language w.r.t
      Header Set. Changed x-my-header to mynewheader.  Added text in the
      HeaderEmission section indicating that the application may also be
      able to free up memory more quickly.  Added information in
      Security Considerations section.

A.2.

A.4.  Since draft-ietf-httpbis-header-compression-01

      Fixed bug/omission in integer representation algorithm.

      Changed the document title.

      Header matching text rewritten.

      Changed the definition of header emission.

      Changed the name of the setting which dictates how much memory the
      compression context should use.

      Removed "specific use cases" section

      Corrected erroneous statement about what index can be contained in
      one byte

      Added descriptions of opcodes

      Removed security claims from introduction.

Appendix B.  Initial Header Tables

   [[anchor11:  Static Table

   The static table consists of an unchangable ordered list of (name,
   value) pairs.  The first entry in the table is always represented by
   the index len(header table), and the last entry in the table is
   represented by the index len(header table)+len(static table)-1.

   [[anchor9: The ordering of these tables is currently arbitrary.  The
   tables in this section should be updated and ordered such that the
   table entries with the smallest indices are those which, based on a
   statistical analysis of header names the frequency and specific of use weighted by size,
   achieve the largest decrease in bytes transmitted subject to HTTP 2.0
   header field rules (like removal of some headers).]]
   [[anchor12: These tables are not adapted for headers contained in
   PUSH_PROMISE frames.  Either the tables can be merged, or the table
   for responses can header fields).  This set of
   header fields is currently very likely incomplete, and should be updated.]]

B.1.  Requests made
   complete.]]

   The following table lists the pre-defined headers header fields that make-up
   the
   initial static header table user to represent requests sent from a client to
   a server.

              +-------+---------------------+--------------+ table.

          +-------+-----------------------------+--------------+
          | Index | Header Name                 | Header Value |
              +-------+---------------------+--------------+
          +-------+-----------------------------+--------------+
          | 0     | :scheme :authority                  | http              |
          | 1     | :scheme :method                     | https GET          |
          | 2     | :host :method                     | POST         |
          | 3     | :path                       | /            |
          | 4     | :method :path                       | GET /index.html  |
          | 5     | accept :scheme                     | http         |
          | 6     | accept-charset :scheme                     | https        |
          | 7     | accept-encoding :status                     | 200          |
          | 8     | accept-language :status                     | 500          |
          | 9     | cookie :status                     | 404          |
          | 10    | if-modified-since :status                     | 403          |
          | 11    | user-agent :status                     | 400          |
          | 12    | referer :status                     | 401          |
          | 13    | authorization accept-charset              |              |
          | 14    | allow accept-encoding             |              |
          | 15    | cache-control accept-language             |              |
          | 16    | connection accept-ranges               |              |
          | 17    | content-length accept                      |              |
          | 18    | content-type access-control-allow-origin |              |
          | 19    | date age                         |              |
          | 20    | expect allow                       |              |
          | 21    | from authorization               |              |
          | 22    | if-match cache-control               |              |
          | 23    | if-none-match content-disposition         |              |
          | 24    | if-range content-encoding            |              |
          | 25    | if-unmodified-since content-language            |              |
          | 26    | max-forwards content-length              |              |
          | 27    | proxy-authorization content-location            |              |
          | 28    | range content-range               |              |
          | 29    | via                 |              |
              +-------+---------------------+--------------+

                Table 1: Initial Header Table for Requests

B.2.  Responses

   The following table lists the pre-defined headers that make-up the
   initial header table used to represent responses sent from a server
   to a client.  The same header table is also used to represent request
   headers sent from a server to a client in a PUSH_PROMISE frame.

          +-------+-----------------------------+--------------+
          | Index | Header Name                 | Header Value |
          +-------+-----------------------------+--------------+
          | 0     | :status content-type                | 200              |
          | 1 30    | age cookie                      |              |
          | 2 31    | cache-control date                        |              |
          | 3 32    | content-length etag                        |              |
          | 4 33    | content-type expect                      |              |
          | 5 34    | date expires                     |              |
          | 6 35    | etag from                        |              |
          | 7 36    | expires if-match                    |              |
          | 8 37    | last-modified if-modified-since           |              |
          | 9 38    | server if-none-match               |              |
          | 10 39    | set-cookie if-range                    |              |
          | 11 40    | vary if-unmodified-since         |              |
          | 12 41    | via last-modified               |              |
          | 13 42    | access-control-allow-origin link                        |              |
          | 14 43    | accept-ranges location                    |              |
          | 15 44    | allow max-forwards                |              |
          | 16 45    | connection proxy-authenticate          |              |
          | 17 46    | content-disposition proxy-authorization         |              |
          | 18 47    | content-encoding range                       |              |
          | 19 48    | content-language referer                     |              |
          | 20 49    | content-location refresh                     |              |
          | 21 50    | content-range retry-after                 |              |
          | 22 51    | link server                      |              |
          | 23 52    | location set-cookie                  |              |
          | 24 53    | proxy-authenticate strict-transport-security   |              |
          | 25 54    | refresh transfer-encoding           |              |
          | 26 55    | retry-after user-agent                  |              |
          | 27 56    | strict-transport-security vary                        |              |
          | 28 57    | transfer-encoding via                         |              |
          | 29 58    | www-authenticate            |              |
          +-------+-----------------------------+--------------+

                       Table 2: Initial Header 1: Static Table for Responses

Appendix C.  Example

   Here is an example that illustrates different representations and how
   tables are updated. [[anchor15: This section needs to be updated to
   better reflect Entries

   The table give the new processing index of header fields, and include more
   examples.]]

C.1.  First header set each entry in the static table.  The first header set full
   index of each entry, to represent be used for encoding a reference to this
   entry, is computed by adding the number of entries in the following:

   :path: /my-example/index.html
   user-agent: my-user-agent
   mynewheader: first

   The header
   table is empty, all headers are represented as literal
   headers with indexing. to this index.

Appendix C.  Huffman Codes For Requests

   The 'mynewheader' header name is not following Huffman codes are used when encoding string literals in
   the
   header name client to server direction.

   [[anchor10: This table is out of date and needs updating.  In
   particular, EOS needs to be at least 7-bits long and currently is encoded literally.  This gives the following
   representation:

   0x44      (literal header with incremental indexing, name index =
   not.]]

                aligned                                  aligned
                 to                            len        to     len
                 MSB                            in        LSB     in
          sym    as bits                       bits      as hex  bits
         (  0) |11111111|11111111|11110111|010 [27]      7ffffba [27]
         (  1) |11111111|11111111|11110111|011 [27]      7ffffbb [27]
         (  2) |11111111|11111111|11110111|100 [27]      7ffffbc [27]
         (  3)
   0x16      (header value string length = 22)
   /my-example/index.html
   0x4D      (literal header with incremental indexing, name index = |11111111|11111111|11110111|101 [27]      7ffffbd [27]
         (  4) |11111111|11111111|11110111|110 [27]      7ffffbe [27]
         (  5) |11111111|11111111|11110111|111 [27]      7ffffbf [27]
         (  6) |11111111|11111111|11111000|000 [27]      7ffffc0 [27]
         (  7) |11111111|11111111|11111000|001 [27]      7ffffc1 [27]
         (  8) |11111111|11111111|11111000|010 [27]      7ffffc2 [27]
         (  9) |11111111|11111111|11111000|011 [27]      7ffffc3 [27]
         ( 10) |11111111|11111111|11111000|100 [27]      7ffffc4 [27]
         ( 11) |11111111|11111111|11111000|101 [27]      7ffffc5 [27]
         ( 12)
   0x0D      (header value string length = |11111111|11111111|11111000|110 [27]      7ffffc6 [27]
         ( 13)
   my-user-agent
   0x40      (literal header with incremental indexing, new name)
   0x0B      (header name string length = 11)
   mynewheader
   0x05      (header value string length = 5)
   first |11111111|11111111|11111000|111 [27]      7ffffc7 [27]
         ( 14) |11111111|11111111|11111001|000 [27]      7ffffc8 [27]
         ( 15) |11111111|11111111|11111001|001 [27]      7ffffc9 [27]
         ( 16) |11111111|11111111|11111001|010 [27]      7ffffca [27]
         ( 17) |11111111|11111111|11111001|011 [27]      7ffffcb [27]
         ( 18) |11111111|11111111|11111001|100 [27]      7ffffcc [27]
         ( 19) |11111111|11111111|11111001|101 [27]      7ffffcd [27]
         ( 20) |11111111|11111111|11111001|110 [27]      7ffffce [27]
         ( 21) |11111111|11111111|11111001|111 [27]      7ffffcf [27]
         ( 22) |11111111|11111111|11111010|000 [27]      7ffffd0 [27]
         ( 23) |11111111|11111111|11111010|001 [27]      7ffffd1 [27]
         ( 24) |11111111|11111111|11111010|010 [27]      7ffffd2 [27]
         ( 25) |11111111|11111111|11111010|011 [27]      7ffffd3 [27]
         ( 26) |11111111|11111111|11111010|100 [27]      7ffffd4 [27]
         ( 27) |11111111|11111111|11111010|101 [27]      7ffffd5 [27]
         ( 28) |11111111|11111111|11111010|110 [27]      7ffffd6 [27]
         ( 29) |11111111|11111111|11111010|111 [27]      7ffffd7 [27]
         ( 30) |11111111|11111111|11111011|000 [27]      7ffffd8 [27]
         ( 31) |11111111|11111111|11111011|001 [27]      7ffffd9 [27]
     ' ' ( 32) |11101000| [8]                                  e8 [8]
     '!' ( 33) |11111111|1100 [12]                           ffc [12]
     '"' ( 34) |11111111|111010 [14]                        3ffa [14]
     '#' ( 35) |11111111|1111100 [15]                       7ffc [15]
     '$' ( 36) |11111111|1111101 [15]                       7ffd [15]
     '%' ( 37) |100100 [6]                                     24 [6]
     '&' ( 38) |1101110 [7]                                    6e [7]
     ''' ( 39) |11111111|1111110 [15]                       7ffe [15]
     '(' ( 40) |11111111|010 [11]                            7fa [11]
     ')' ( 41) |11111111|011 [11]                            7fb [11]
     '*' ( 42) |11111110|10 [10]                             3fa [10]
     '+' ( 43) |11111111|100 [11]                            7fc [11]
     ',' ( 44) |11101001| [8]                                  e9 [8]
     '-' ( 45) |100101 [6]                                     25 [6]
     '.' ( 46) |00100 [5]                                       4 [5]
     '/' ( 47) |0000 [4]                                        0 [4]
     '0' ( 48) |00101 [5]                                       5 [5]
     '1' ( 49) |00110 [5]                                       6 [5]
     '2' ( 50) |00111 [5]                                       7 [5]
     '3' ( 51) |100110 [6]                                     26 [6]
     '4' ( 52) |100111 [6]                                     27 [6]
     '5' ( 53) |101000 [6]                                     28 [6]
     '6' ( 54) |101001 [6]                                     29 [6]
     '7' ( 55) |101010 [6]                                     2a [6]
     '8' ( 56) |101011 [6]                                     2b [6]
     '9' ( 57) |101100 [6]                                     2c [6]
     ':' ( 58) |11110110|0 [9]                                1ec [9]
     ';' ( 59) |11101010| [8]                                  ea [8]
     '<' ( 60) |11111111|11111111|10 [18]                  3fffe [18]
     '=' ( 61) |101101 [6]                                     2d [6]
     '>' ( 62) |11111111|11111110|0 [17]                   1fffc [17]
     '?' ( 63) |11110110|1 [9]                                1ed [9]
     '@' ( 64) |11111111|111011 [14]                        3ffb [14]
     'A' ( 65) |1101111 [7]                                    6f [7]
     'B' ( 66) |11101011| [8]                                  eb [8]
     'C' ( 67) |11101100| [8]                                  ec [8]
     'D' ( 68) |11101101| [8]                                  ed [8]
     'E' ( 69) |11101110| [8]                                  ee [8]
     'F' ( 70) |1110000 [7]                                    70 [7]
     'G' ( 71) |11110111|0 [9]                                1ee [9]
     'H' ( 72) |11110111|1 [9]                                1ef [9]
     'I' ( 73) |11111000|0 [9]                                1f0 [9]
     'J' ( 74) |11111000|1 [9]                                1f1 [9]
     'K' ( 75) |11111110|11 [10]                             3fb [10]
     'L' ( 76) |11111001|0 [9]                                1f2 [9]
     'M' ( 77) |11101111| [8]                                  ef [8]
     'N' ( 78) |11111001|1 [9]                                1f3 [9]
     'O' ( 79) |11111010|0 [9]                                1f4 [9]
     'P' ( 80) |11111010|1 [9]                                1f5 [9]
     'Q' ( 81) |11111011|0 [9]                                1f6 [9]
     'R' ( 82) |11111011|1 [9]                                1f7 [9]
     'S' ( 83) |11110000| [8]                                  f0 [8]
     'T' ( 84) |11110001| [8]                                  f1 [8]
     'U' ( 85) |11111100|0 [9]                                1f8 [9]
     'V' ( 86) |11111100|1 [9]                                1f9 [9]
     'W' ( 87) |11111101|0 [9]                                1fa [9]
     'X' ( 88) |11111101|1 [9]                                1fb [9]
     'Y' ( 89) |11111110|0 [9]                                1fc [9]
     'Z' ( 90) |11111111|00 [10]                             3fc [10]
     '[' ( 91) |11111111|111100 [14]                        3ffc [14]
     '\' ( 92) |11111111|11111111|11111011|010 [27]      7ffffda [27]
     ']' ( 93) |11111111|11100 [13]                         1ffc [13]
     '^' ( 94) |11111111|111101 [14]                        3ffd [14]
     '_' ( 95) |101110 [6]                                     2e [6]
     '`' ( 96) |11111111|11111111|110 [19]                 7fffe [19]
     'a' ( 97) |01000 [5]                                       8 [5]
     'b' ( 98) |101111 [6]                                     2f [6]
     'c' ( 99) |01001 [5]                                       9 [5]
     'd' (100) |110000 [6]                                     30 [6]
     'e' (101) |0001 [4]                                        1 [4]
     'f' (102) |110001 [6]                                     31 [6]
     'g' (103) |110010 [6]                                     32 [6]
     'h' (104) |110011 [6]                                     33 [6]
     'i' (105) |01010 [5]                                       a [5]
     'j' (106) |1110001 [7]                                    71 [7]
     'k' (107) |1110010 [7]                                    72 [7]
     'l' (108) |01011 [5]                                       b [5]
     'm' (109) |110100 [6]                                     34 [6]
     'n' (110) |01100 [5]                                       c [5]
     'o' (111) |01101 [5]                                       d [5]
     'p' (112) |01110 [5]                                       e [5]
     'q' (113) |11110010| [8]                                  f2 [8]
     'r' (114) |01111 [5]                                       f [5]
     's' (115) |10000 [5]                                      10 [5]
     't' (116) |10001 [5]                                      11 [5]
     'u' (117) |110101 [6]                                     35 [6]
     'v' (118) |1110011 [7]                                    73 [7]
     'w' (119) |110110 [6]                                     36 [6]
     'x' (120) |11110011| [8]                                  f3 [8]
     'y' (121) |11110100| [8]                                  f4 [8]
     'z' (122) |11110101| [8]                                  f5 [8]
     '{' (123) |11111111|11111110|1 [17]                   1fffd [17]
     '|' (124) |11111111|101 [11]                            7fd [11]
     '}' (125) |11111111|11111111|0 [17]                   1fffe [17]
     '~' (126) |11111111|1101 [12]                           ffd [12]
         (127) |11111111|11111111|11111011|011 [27]      7ffffdb [27]
         (128) |11111111|11111111|11111011|100 [27]      7ffffdc [27]
         (129) |11111111|11111111|11111011|101 [27]      7ffffdd [27]
         (130) |11111111|11111111|11111011|110 [27]      7ffffde [27]
         (131) |11111111|11111111|11111011|111 [27]      7ffffdf [27]
         (132) |11111111|11111111|11111100|000 [27]      7ffffe0 [27]
         (133) |11111111|11111111|11111100|001 [27]      7ffffe1 [27]
         (134) |11111111|11111111|11111100|010 [27]      7ffffe2 [27]
         (135) |11111111|11111111|11111100|011 [27]      7ffffe3 [27]
         (136) |11111111|11111111|11111100|100 [27]      7ffffe4 [27]
         (137) |11111111|11111111|11111100|101 [27]      7ffffe5 [27]
         (138) |11111111|11111111|11111100|110 [27]      7ffffe6 [27]
         (139) |11111111|11111111|11111100|111 [27]      7ffffe7 [27]
         (140) |11111111|11111111|11111101|000 [27]      7ffffe8 [27]
         (141) |11111111|11111111|11111101|001 [27]      7ffffe9 [27]
         (142) |11111111|11111111|11111101|010 [27]      7ffffea [27]
         (143) |11111111|11111111|11111101|011 [27]      7ffffeb [27]
         (144) |11111111|11111111|11111101|100 [27]      7ffffec [27]
         (145) |11111111|11111111|11111101|101 [27]      7ffffed [27]
         (146) |11111111|11111111|11111101|110 [27]      7ffffee [27]
         (147) |11111111|11111111|11111101|111 [27]      7ffffef [27]
         (148) |11111111|11111111|11111110|000 [27]      7fffff0 [27]
         (149) |11111111|11111111|11111110|001 [27]      7fffff1 [27]
         (150) |11111111|11111111|11111110|010 [27]      7fffff2 [27]
         (151) |11111111|11111111|11111110|011 [27]      7fffff3 [27]
         (152) |11111111|11111111|11111110|100 [27]      7fffff4 [27]
         (153) |11111111|11111111|11111110|101 [27]      7fffff5 [27]
         (154) |11111111|11111111|11111110|110 [27]      7fffff6 [27]
         (155) |11111111|11111111|11111110|111 [27]      7fffff7 [27]
         (156) |11111111|11111111|11111111|000 [27]      7fffff8 [27]
         (157) |11111111|11111111|11111111|001 [27]      7fffff9 [27]
         (158) |11111111|11111111|11111111|010 [27]      7fffffa [27]
         (159) |11111111|11111111|11111111|011 [27]      7fffffb [27]
         (160) |11111111|11111111|11111111|100 [27]      7fffffc [27]
         (161) |11111111|11111111|11111111|101 [27]      7fffffd [27]
         (162) |11111111|11111111|11111111|110 [27]      7fffffe [27]
         (163) |11111111|11111111|11111111|111 [27]      7ffffff [27]
         (164) |11111111|11111111|11100000|00 [26]       3ffff80 [26]
         (165) |11111111|11111111|11100000|01 [26]       3ffff81 [26]
         (166) |11111111|11111111|11100000|10 [26]       3ffff82 [26]
         (167) |11111111|11111111|11100000|11 [26]       3ffff83 [26]
         (168) |11111111|11111111|11100001|00 [26]       3ffff84 [26]
         (169) |11111111|11111111|11100001|01 [26]       3ffff85 [26]
         (170) |11111111|11111111|11100001|10 [26]       3ffff86 [26]
         (171) |11111111|11111111|11100001|11 [26]       3ffff87 [26]
         (172) |11111111|11111111|11100010|00 [26]       3ffff88 [26]
         (173) |11111111|11111111|11100010|01 [26]       3ffff89 [26]
         (174) |11111111|11111111|11100010|10 [26]       3ffff8a [26]
         (175) |11111111|11111111|11100010|11 [26]       3ffff8b [26]
         (176) |11111111|11111111|11100011|00 [26]       3ffff8c [26]
         (177) |11111111|11111111|11100011|01 [26]       3ffff8d [26]
         (178) |11111111|11111111|11100011|10 [26]       3ffff8e [26]
         (179) |11111111|11111111|11100011|11 [26]       3ffff8f [26]
         (180) |11111111|11111111|11100100|00 [26]       3ffff90 [26]
         (181) |11111111|11111111|11100100|01 [26]       3ffff91 [26]
         (182) |11111111|11111111|11100100|10 [26]       3ffff92 [26]
         (183) |11111111|11111111|11100100|11 [26]       3ffff93 [26]
         (184) |11111111|11111111|11100101|00 [26]       3ffff94 [26]
         (185) |11111111|11111111|11100101|01 [26]       3ffff95 [26]
         (186) |11111111|11111111|11100101|10 [26]       3ffff96 [26]
         (187) |11111111|11111111|11100101|11 [26]       3ffff97 [26]
         (188) |11111111|11111111|11100110|00 [26]       3ffff98 [26]
         (189) |11111111|11111111|11100110|01 [26]       3ffff99 [26]
         (190) |11111111|11111111|11100110|10 [26]       3ffff9a [26]
         (191) |11111111|11111111|11100110|11 [26]       3ffff9b [26]
         (192) |11111111|11111111|11100111|00 [26]       3ffff9c [26]
         (193) |11111111|11111111|11100111|01 [26]       3ffff9d [26]
         (194) |11111111|11111111|11100111|10 [26]       3ffff9e [26]
         (195) |11111111|11111111|11100111|11 [26]       3ffff9f [26]
         (196) |11111111|11111111|11101000|00 [26]       3ffffa0 [26]
         (197) |11111111|11111111|11101000|01 [26]       3ffffa1 [26]
         (198) |11111111|11111111|11101000|10 [26]       3ffffa2 [26]
         (199) |11111111|11111111|11101000|11 [26]       3ffffa3 [26]
         (200) |11111111|11111111|11101001|00 [26]       3ffffa4 [26]
         (201) |11111111|11111111|11101001|01 [26]       3ffffa5 [26]
         (202) |11111111|11111111|11101001|10 [26]       3ffffa6 [26]
         (203) |11111111|11111111|11101001|11 [26]       3ffffa7 [26]
         (204) |11111111|11111111|11101010|00 [26]       3ffffa8 [26]
         (205) |11111111|11111111|11101010|01 [26]       3ffffa9 [26]
         (206) |11111111|11111111|11101010|10 [26]       3ffffaa [26]
         (207) |11111111|11111111|11101010|11 [26]       3ffffab [26]
         (208) |11111111|11111111|11101011|00 [26]       3ffffac [26]
         (209) |11111111|11111111|11101011|01 [26]       3ffffad [26]
         (210) |11111111|11111111|11101011|10 [26]       3ffffae [26]
         (211) |11111111|11111111|11101011|11 [26]       3ffffaf [26]
         (212) |11111111|11111111|11101100|00 [26]       3ffffb0 [26]
         (213) |11111111|11111111|11101100|01 [26]       3ffffb1 [26]
         (214) |11111111|11111111|11101100|10 [26]       3ffffb2 [26]
         (215) |11111111|11111111|11101100|11 [26]       3ffffb3 [26]
         (216) |11111111|11111111|11101101|00 [26]       3ffffb4 [26]
         (217) |11111111|11111111|11101101|01 [26]       3ffffb5 [26]
         (218) |11111111|11111111|11101101|10 [26]       3ffffb6 [26]
         (219) |11111111|11111111|11101101|11 [26]       3ffffb7 [26]
         (220) |11111111|11111111|11101110|00 [26]       3ffffb8 [26]
         (221) |11111111|11111111|11101110|01 [26]       3ffffb9 [26]
         (222) |11111111|11111111|11101110|10 [26]       3ffffba [26]
         (223) |11111111|11111111|11101110|11 [26]       3ffffbb [26]
         (224) |11111111|11111111|11101111|00 [26]       3ffffbc [26]
         (225) |11111111|11111111|11101111|01 [26]       3ffffbd [26]
         (226) |11111111|11111111|11101111|10 [26]       3ffffbe [26]
         (227) |11111111|11111111|11101111|11 [26]       3ffffbf [26]
         (228) |11111111|11111111|11110000|00 [26]       3ffffc0 [26]
         (229) |11111111|11111111|11110000|01 [26]       3ffffc1 [26]
         (230) |11111111|11111111|11110000|10 [26]       3ffffc2 [26]
         (231) |11111111|11111111|11110000|11 [26]       3ffffc3 [26]
         (232) |11111111|11111111|11110001|00 [26]       3ffffc4 [26]
         (233) |11111111|11111111|11110001|01 [26]       3ffffc5 [26]
         (234) |11111111|11111111|11110001|10 [26]       3ffffc6 [26]
         (235) |11111111|11111111|11110001|11 [26]       3ffffc7 [26]
         (236) |11111111|11111111|11110010|00 [26]       3ffffc8 [26]
         (237) |11111111|11111111|11110010|01 [26]       3ffffc9 [26]
         (238) |11111111|11111111|11110010|10 [26]       3ffffca [26]
         (239) |11111111|11111111|11110010|11 [26]       3ffffcb [26]
         (240) |11111111|11111111|11110011|00 [26]       3ffffcc [26]
         (241) |11111111|11111111|11110011|01 [26]       3ffffcd [26]
         (242) |11111111|11111111|11110011|10 [26]       3ffffce [26]
         (243) |11111111|11111111|11110011|11 [26]       3ffffcf [26]
         (244) |11111111|11111111|11110100|00 [26]       3ffffd0 [26]
         (245) |11111111|11111111|11110100|01 [26]       3ffffd1 [26]
         (246) |11111111|11111111|11110100|10 [26]       3ffffd2 [26]
         (247) |11111111|11111111|11110100|11 [26]       3ffffd3 [26]
         (248) |11111111|11111111|11110101|00 [26]       3ffffd4 [26]
         (249) |11111111|11111111|11110101|01 [26]       3ffffd5 [26]
         (250) |11111111|11111111|11110101|10 [26]       3ffffd6 [26]
         (251) |11111111|11111111|11110101|11 [26]       3ffffd7 [26]
         (252) |11111111|11111111|11110110|00 [26]       3ffffd8 [26]
         (253) |11111111|11111111|11110110|01 [26]       3ffffd9 [26]
         (254) |11111111|11111111|11110110|10 [26]       3ffffda [26]
         (255) |11111111|11111111|11110110|11 [26]       3ffffdb [26]
     EOS (256) |11111111|11111111|11110111|00 [26]       3ffffdc [26]

Appendix D.  Huffman Codes for Responses

   The header following Huffman codes are used when encoding string literals in
   the server to client direction.

   [[anchor11: This table is out of date and needs updating.  In
   particular, EOS needs to be at least 7-bits long and currently is
   not.]]

                aligned                                  aligned
                 to                           len         to     len
                 MSB                           in         LSB     in
          sym    as follows after the processing bits                      bits       as hex  bits
         (  0) |11111111|11111111|11011110|0 [25]        1ffffbc [25]
         (  1) |11111111|11111111|11011110|1 [25]        1ffffbd [25]
         (  2) |11111111|11111111|11011111|0 [25]        1ffffbe [25]
         (  3) |11111111|11111111|11011111|1 [25]        1ffffbf [25]
         (  4) |11111111|11111111|11100000|0 [25]        1ffffc0 [25]
         (  5) |11111111|11111111|11100000|1 [25]        1ffffc1 [25]
         (  6) |11111111|11111111|11100001|0 [25]        1ffffc2 [25]
         (  7) |11111111|11111111|11100001|1 [25]        1ffffc3 [25]
         (  8) |11111111|11111111|11100010|0 [25]        1ffffc4 [25]
         (  9) |11111111|11111111|11100010|1 [25]        1ffffc5 [25]
         ( 10) |11111111|11111111|11100011|0 [25]        1ffffc6 [25]
         ( 11) |11111111|11111111|11100011|1 [25]        1ffffc7 [25]
         ( 12) |11111111|11111111|11100100|0 [25]        1ffffc8 [25]
         ( 13) |11111111|11111111|11100100|1 [25]        1ffffc9 [25]
         ( 14) |11111111|11111111|11100101|0 [25]        1ffffca [25]
         ( 15) |11111111|11111111|11100101|1 [25]        1ffffcb [25]
         ( 16) |11111111|11111111|11100110|0 [25]        1ffffcc [25]
         ( 17) |11111111|11111111|11100110|1 [25]        1ffffcd [25]
         ( 18) |11111111|11111111|11100111|0 [25]        1ffffce [25]
         ( 19) |11111111|11111111|11100111|1 [25]        1ffffcf [25]
         ( 20) |11111111|11111111|11101000|0 [25]        1ffffd0 [25]
         ( 21) |11111111|11111111|11101000|1 [25]        1ffffd1 [25]
         ( 22) |11111111|11111111|11101001|0 [25]        1ffffd2 [25]
         ( 23) |11111111|11111111|11101001|1 [25]        1ffffd3 [25]
         ( 24) |11111111|11111111|11101010|0 [25]        1ffffd4 [25]
         ( 25) |11111111|11111111|11101010|1 [25]        1ffffd5 [25]
         ( 26) |11111111|11111111|11101011|0 [25]        1ffffd6 [25]
         ( 27) |11111111|11111111|11101011|1 [25]        1ffffd7 [25]
         ( 28) |11111111|11111111|11101100|0 [25]        1ffffd8 [25]
         ( 29) |11111111|11111111|11101100|1 [25]        1ffffd9 [25]
         ( 30) |11111111|11111111|11101101|0 [25]        1ffffda [25]
         ( 31) |11111111|11111111|11101101|1 [25]        1ffffdb [25]
     ' ' ( 32) |0000 [4]                                        0 [4]
     '!' ( 33) |11111111|1010 [12]                           ffa [12]
     '"' ( 34) |1101010 [7]                                    6a [7]
     '#' ( 35) |11111111|11010 [13]                         1ffa [13]
     '$' ( 36) |11111111|111100 [14]                        3ffc [14]
     '%' ( 37) |11110110|0 [9]                                1ec [9]
     '&' ( 38) |11111110|00 [10]                             3f8 [10]
     ''' ( 39) |11111111|11011 [13]                         1ffb [13]
     '(' ( 40) |11110110|1 [9]                                1ed [9]
     ')' ( 41) |11110111|0 [9]                                1ee [9]
     '*' ( 42) |11111111|1011 [12]                           ffb [12]
     '+' ( 43) |11111111|010 [11]                            7fa [11]
     ',' ( 44) |100010 [6]                                     22 [6]
     '-' ( 45) |100011 [6]                                     23 [6]
     '.' ( 46) |100100 [6]                                     24 [6]
     '/' ( 47) |1101011 [7]                                    6b [7]
     '0' ( 48) |0001 [4]                                        1 [4]
     '1' ( 49) |0010 [4]                                        2 [4]
     '2' ( 50) |0011 [4]                                        3 [4]
     '3' ( 51) |01000 [5]                                       8 [5]
     '4' ( 52) |01001 [5]                                       9 [5]
     '5' ( 53) |01010 [5]                                       a [5]
     '6' ( 54) |100101 [6]                                     25 [6]
     '7' ( 55) |100110 [6]                                     26 [6]
     '8' ( 56) |01011 [5]                                       b [5]
     '9' ( 57) |01100 [5]                                       c [5]
     ':' ( 58) |01101 [5]                                       d [5]
     ';' ( 59) |11110111|1 [9]                                1ef [9]
     '<' ( 60) |11111111|11111010| [16]                     fffa [16]
     '=' ( 61) |1101100 [7]                                    6c [7]
     '>' ( 62) |11111111|11100 [13]                         1ffc [13]
     '?' ( 63) |11111111|1100 [12]                           ffc [12]
     '@' ( 64) |11111111|11111011| [16]                     fffb [16]
     'A' ( 65) |1101101 [7]                                    6d [7]
     'B' ( 66) |11101010| [8]                                  ea [8]
     'C' ( 67) |11101011| [8]                                  eb [8]
     'D' ( 68) |11101100| [8]                                  ec [8]
     'E' ( 69) |11101101| [8]                                  ed [8]
     'F' ( 70) |11101110| [8]                                  ee [8]
     'G' ( 71) |100111 [6]                                     27 [6]
     'H' ( 72) |11111000|0 [9]                                1f0 [9]
     'I' ( 73) |11101111| [8]                                  ef [8]
     'J' ( 74) |11110000| [8]                                  f0 [8]
     'K' ( 75) |11111110|01 [10]                             3f9 [10]
     'L' ( 76) |11111000|1 [9]                                1f1 [9]
     'M' ( 77) |101000 [6]                                     28 [6]
     'N' ( 78) |11110001| [8]                                  f1 [8]
     'O' ( 79) |11110010| [8]                                  f2 [8]
     'P' ( 80) |11111001|0 [9]                                1f2 [9]
     'Q' ( 81) |11111110|10 [10]                             3fa [10]
     'R' ( 82) |11111001|1 [9]                                1f3 [9]
     'S' ( 83) |101001 [6]                                     29 [6]
     'T' ( 84) |01110 [5]                                       e [5]
     'U' ( 85) |11111010|0 [9]                                1f4 [9]
     'V' ( 86) |11111010|1 [9]                                1f5 [9]
     'W' ( 87) |11110011| [8]                                  f3 [8]
     'X' ( 88) |11111110|11 [10]                             3fb [10]
     'Y' ( 89) |11111011|0 [9]                                1f6 [9]
     'Z' ( 90) |11111111|00 [10]                             3fc [10]
     '[' ( 91) |11111111|011 [11]                            7fb [11]
     '\' ( 92) |11111111|11101 [13]                         1ffd [13]
     ']' ( 93) |11111111|100 [11]                            7fc [11]
     '^' ( 94) |11111111|1111100 [15]                       7ffc [15]
     '_' ( 95) |11111011|1 [9]                                1f7 [9]
     '`' ( 96) |11111111|11111111|0 [17]                   1fffe [17]
     'a' ( 97) |01111 [5]                                       f [5]
     'b' ( 98) |1101110 [7]                                    6e [7]
     'c' ( 99) |101010 [6]                                     2a [6]
     'd' (100) |101011 [6]                                     2b [6]
     'e' (101) |10000 [5]                                      10 [5]
     'f' (102) |1101111 [7]                                    6f [7]
     'g' (103) |1110000 [7]                                    70 [7]
     'h' (104) |1110001 [7]                                    71 [7]
     'i' (105) |101100 [6]                                     2c [6]
     'j' (106) |11111100|0 [9]                                1f8 [9]
     'k' (107) |11111100|1 [9]                                1f9 [9]
     'l' (108) |1110010 [7]                                    72 [7]
     'm' (109) |101101 [6]                                     2d [6]
     'n' (110) |101110 [6]                                     2e [6]
     'o' (111) |101111 [6]                                     2f [6]
     'p' (112) |110000 [6]                                     30 [6]
     'q' (113) |11111101|0 [9]                                1fa [9]
     'r' (114) |110001 [6]                                     31 [6]
     's' (115) |110010 [6]                                     32 [6]
     't' (116) |110011 [6]                                     33 [6]
     'u' (117) |110100 [6]                                     34 [6]
     'v' (118) |1110011 [7]                                    73 [7]
     'w' (119) |11110100| [8]                                  f4 [8]
     'x' (120) |1110100 [7]                                    74 [7]
     'y' (121) |11110101| [8]                                  f5 [8]
     'z' (122) |11111101|1 [9]                                1fb [9]
     '{' (123) |11111111|11111100| [16]                     fffc [16]
     '|' (124) |11111111|111101 [14]                        3ffd [14]
     '}' (125) |11111111|11111101| [16]                     fffd [16]
     '~' (126) |11111111|11111110| [16]                     fffe [16]
         (127) |11111111|11111111|11101110|0 [25]        1ffffdc [25]
         (128) |11111111|11111111|11101110|1 [25]        1ffffdd [25]
         (129) |11111111|11111111|11101111|0 [25]        1ffffde [25]
         (130) |11111111|11111111|11101111|1 [25]        1ffffdf [25]
         (131) |11111111|11111111|11110000|0 [25]        1ffffe0 [25]
         (132) |11111111|11111111|11110000|1 [25]        1ffffe1 [25]
         (133) |11111111|11111111|11110001|0 [25]        1ffffe2 [25]
         (134) |11111111|11111111|11110001|1 [25]        1ffffe3 [25]
         (135) |11111111|11111111|11110010|0 [25]        1ffffe4 [25]
         (136) |11111111|11111111|11110010|1 [25]        1ffffe5 [25]
         (137) |11111111|11111111|11110011|0 [25]        1ffffe6 [25]
         (138) |11111111|11111111|11110011|1 [25]        1ffffe7 [25]
         (139) |11111111|11111111|11110100|0 [25]        1ffffe8 [25]
         (140) |11111111|11111111|11110100|1 [25]        1ffffe9 [25]
         (141) |11111111|11111111|11110101|0 [25]        1ffffea [25]
         (142) |11111111|11111111|11110101|1 [25]        1ffffeb [25]
         (143) |11111111|11111111|11110110|0 [25]        1ffffec [25]
         (144) |11111111|11111111|11110110|1 [25]        1ffffed [25]
         (145) |11111111|11111111|11110111|0 [25]        1ffffee [25]
         (146) |11111111|11111111|11110111|1 [25]        1ffffef [25]
         (147) |11111111|11111111|11111000|0 [25]        1fffff0 [25]
         (148) |11111111|11111111|11111000|1 [25]        1fffff1 [25]
         (149) |11111111|11111111|11111001|0 [25]        1fffff2 [25]
         (150) |11111111|11111111|11111001|1 [25]        1fffff3 [25]
         (151) |11111111|11111111|11111010|0 [25]        1fffff4 [25]
         (152) |11111111|11111111|11111010|1 [25]        1fffff5 [25]
         (153) |11111111|11111111|11111011|0 [25]        1fffff6 [25]
         (154) |11111111|11111111|11111011|1 [25]        1fffff7 [25]
         (155) |11111111|11111111|11111100|0 [25]        1fffff8 [25]
         (156) |11111111|11111111|11111100|1 [25]        1fffff9 [25]
         (157) |11111111|11111111|11111101|0 [25]        1fffffa [25]
         (158) |11111111|11111111|11111101|1 [25]        1fffffb [25]
         (159) |11111111|11111111|11111110|0 [25]        1fffffc [25]
         (160) |11111111|11111111|11111110|1 [25]        1fffffd [25]
         (161) |11111111|11111111|11111111|0 [25]        1fffffe [25]
         (162) |11111111|11111111|11111111|1 [25]        1ffffff [25]
         (163) |11111111|11111111|10000000| [24]          ffff80 [24]
         (164) |11111111|11111111|10000001| [24]          ffff81 [24]
         (165) |11111111|11111111|10000010| [24]          ffff82 [24]
         (166) |11111111|11111111|10000011| [24]          ffff83 [24]
         (167) |11111111|11111111|10000100| [24]          ffff84 [24]
         (168) |11111111|11111111|10000101| [24]          ffff85 [24]
         (169) |11111111|11111111|10000110| [24]          ffff86 [24]
         (170) |11111111|11111111|10000111| [24]          ffff87 [24]
         (171) |11111111|11111111|10001000| [24]          ffff88 [24]
         (172) |11111111|11111111|10001001| [24]          ffff89 [24]
         (173) |11111111|11111111|10001010| [24]          ffff8a [24]
         (174) |11111111|11111111|10001011| [24]          ffff8b [24]
         (175) |11111111|11111111|10001100| [24]          ffff8c [24]
         (176) |11111111|11111111|10001101| [24]          ffff8d [24]
         (177) |11111111|11111111|10001110| [24]          ffff8e [24]
         (178) |11111111|11111111|10001111| [24]          ffff8f [24]
         (179) |11111111|11111111|10010000| [24]          ffff90 [24]
         (180) |11111111|11111111|10010001| [24]          ffff91 [24]
         (181) |11111111|11111111|10010010| [24]          ffff92 [24]
         (182) |11111111|11111111|10010011| [24]          ffff93 [24]
         (183) |11111111|11111111|10010100| [24]          ffff94 [24]
         (184) |11111111|11111111|10010101| [24]          ffff95 [24]
         (185) |11111111|11111111|10010110| [24]          ffff96 [24]
         (186) |11111111|11111111|10010111| [24]          ffff97 [24]
         (187) |11111111|11111111|10011000| [24]          ffff98 [24]
         (188) |11111111|11111111|10011001| [24]          ffff99 [24]
         (189) |11111111|11111111|10011010| [24]          ffff9a [24]
         (190) |11111111|11111111|10011011| [24]          ffff9b [24]
         (191) |11111111|11111111|10011100| [24]          ffff9c [24]
         (192) |11111111|11111111|10011101| [24]          ffff9d [24]
         (193) |11111111|11111111|10011110| [24]          ffff9e [24]
         (194) |11111111|11111111|10011111| [24]          ffff9f [24]
         (195) |11111111|11111111|10100000| [24]          ffffa0 [24]
         (196) |11111111|11111111|10100001| [24]          ffffa1 [24]
         (197) |11111111|11111111|10100010| [24]          ffffa2 [24]
         (198) |11111111|11111111|10100011| [24]          ffffa3 [24]
         (199) |11111111|11111111|10100100| [24]          ffffa4 [24]
         (200) |11111111|11111111|10100101| [24]          ffffa5 [24]
         (201) |11111111|11111111|10100110| [24]          ffffa6 [24]
         (202) |11111111|11111111|10100111| [24]          ffffa7 [24]
         (203) |11111111|11111111|10101000| [24]          ffffa8 [24]
         (204) |11111111|11111111|10101001| [24]          ffffa9 [24]
         (205) |11111111|11111111|10101010| [24]          ffffaa [24]
         (206) |11111111|11111111|10101011| [24]          ffffab [24]
         (207) |11111111|11111111|10101100| [24]          ffffac [24]
         (208) |11111111|11111111|10101101| [24]          ffffad [24]
         (209) |11111111|11111111|10101110| [24]          ffffae [24]
         (210) |11111111|11111111|10101111| [24]          ffffaf [24]
         (211) |11111111|11111111|10110000| [24]          ffffb0 [24]
         (212) |11111111|11111111|10110001| [24]          ffffb1 [24]
         (213) |11111111|11111111|10110010| [24]          ffffb2 [24]
         (214) |11111111|11111111|10110011| [24]          ffffb3 [24]
         (215) |11111111|11111111|10110100| [24]          ffffb4 [24]
         (216) |11111111|11111111|10110101| [24]          ffffb5 [24]
         (217) |11111111|11111111|10110110| [24]          ffffb6 [24]
         (218) |11111111|11111111|10110111| [24]          ffffb7 [24]
         (219) |11111111|11111111|10111000| [24]          ffffb8 [24]
         (220) |11111111|11111111|10111001| [24]          ffffb9 [24]
         (221) |11111111|11111111|10111010| [24]          ffffba [24]
         (222) |11111111|11111111|10111011| [24]          ffffbb [24]
         (223) |11111111|11111111|10111100| [24]          ffffbc [24]
         (224) |11111111|11111111|10111101| [24]          ffffbd [24]
         (225) |11111111|11111111|10111110| [24]          ffffbe [24]
         (226) |11111111|11111111|10111111| [24]          ffffbf [24]
         (227) |11111111|11111111|11000000| [24]          ffffc0 [24]
         (228) |11111111|11111111|11000001| [24]          ffffc1 [24]
         (229) |11111111|11111111|11000010| [24]          ffffc2 [24]
         (230) |11111111|11111111|11000011| [24]          ffffc3 [24]
         (231) |11111111|11111111|11000100| [24]          ffffc4 [24]
         (232) |11111111|11111111|11000101| [24]          ffffc5 [24]
         (233) |11111111|11111111|11000110| [24]          ffffc6 [24]
         (234) |11111111|11111111|11000111| [24]          ffffc7 [24]
         (235) |11111111|11111111|11001000| [24]          ffffc8 [24]
         (236) |11111111|11111111|11001001| [24]          ffffc9 [24]
         (237) |11111111|11111111|11001010| [24]          ffffca [24]
         (238) |11111111|11111111|11001011| [24]          ffffcb [24]
         (239) |11111111|11111111|11001100| [24]          ffffcc [24]
         (240) |11111111|11111111|11001101| [24]          ffffcd [24]
         (241) |11111111|11111111|11001110| [24]          ffffce [24]
         (242) |11111111|11111111|11001111| [24]          ffffcf [24]
         (243) |11111111|11111111|11010000| [24]          ffffd0 [24]
         (244) |11111111|11111111|11010001| [24]          ffffd1 [24]
         (245) |11111111|11111111|11010010| [24]          ffffd2 [24]
         (246) |11111111|11111111|11010011| [24]          ffffd3 [24]
         (247) |11111111|11111111|11010100| [24]          ffffd4 [24]
         (248) |11111111|11111111|11010101| [24]          ffffd5 [24]
         (249) |11111111|11111111|11010110| [24]          ffffd6 [24]
         (250) |11111111|11111111|11010111| [24]          ffffd7 [24]
         (251) |11111111|11111111|11011000| [24]          ffffd8 [24]
         (252) |11111111|11111111|11011001| [24]          ffffd9 [24]
         (253) |11111111|11111111|11011010| [24]          ffffda [24]
         (254) |11111111|11111111|11011011| [24]          ffffdb [24]
         (255) |11111111|11111111|11011100| [24]          ffffdc [24]
     EOS (256) |11111111|11111111|11011101| [24]          ffffdd [24]

Appendix E.  Examples

   A number of these headers:

   Header table
   +---------+----------------+---------------------------+
   |  Index  | Header Name    | examples are worked through here, for both requests and
   responses, and with and without huffman coding.

E.1.  Request Decoding Example With Huffman

   # Header Value              |
   +---------+----------------+---------------------------+
   |    0    | :scheme        | set to be encoded
   :method: GET
   :scheme: http                      |
   +---------+----------------+---------------------------+
   |
   :path: /
   :authority: www.foo.com
   # Hexdump of encoded data which will be decoded
   02 84 f7 77 78 ff 07 83 ce 31 77 06 81 0f 04 88 | ...wx....1w.....
   db 6d 89 8b 5a 44 b7 4f                         | .m..ZD.O

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '02'
       name_index:
           encoded: "02"
           decoded: 2
       value_data_length:
           encoded: "84"
           decoded: 4
       value_data:
           is_huffman_encoded: 1    | :scheme        | https                     |
   +---------+----------------+---------------------------+
   |   ...   | ...            | ...                       |
   +---------+----------------+---------------------------+
   |   37    | warning        |                           |
   +---------+----------------+---------------------------+
   |   38    | :path          | /my-example/index.html    | added header
   +---------+----------------+---------------------------+
   |   39    | user-agent     | my-user-agent             | added header
   +---------+----------------+---------------------------+
   |   40    | mynewheader    | first                     | added header
   +---------+----------------+---------------------------+

   As all the headers in the first
           encoded: "f77778ff"
           decoded: "GET"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '07'
       name_index:
           encoded: "07"
           decoded: 7
       value_data_length:
           encoded: "83"
           decoded: 3
       value_data:
           is_huffman_encoded: 1
           encoded: "ce3177"
           decoded: "http"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '06'
       name_index:
           encoded: "06"
           decoded: 6
       value_data_length:
           encoded: "81"
           decoded: 1
       value_data:
           is_huffman_encoded: 1
           encoded: "0f"
           decoded: "/"

   LITERAL_INCREMENTAL_OPCODE:

           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '04'
       name_index:
           encoded: "04"
           decoded: 4
       value_data_length:
           encoded: "88"
           decoded: 8
       value_data:
           is_huffman_encoded: 1
           encoded: "db6d898b5a44b74f"
           decoded: "www.foo.com"

   # Decoded header set are indexed in the header
   table, all are kept in the reference
   :authority: www.foo.com
   :method: GET
   :path: /
   :scheme: http

   #########################

   # Header set to be encoded
   :method: GET
   :scheme: https
   :path: /
   :authority: www.bar.com
   cache-control: no-cache

   # Hexdump of headers, encoded data which is:

   Reference Set:
   :path, /my-example/index.html
   user-agent, my-user-agent
   mynewheader, first

C.2.  Second will be decoded
   03 84 ce 31 74 3f 02 88 db 6d 89 7a 1e 44 b7 4f | ...1t?...m.z.D.O
   1d 86 63 65 4a 13 98 ff 83 85                   | ..ceJ.....

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '03'
       name_index:
           encoded: "03"
           decoded: 3
       value_data_length:
           encoded: "84"
           decoded: 4
       value_data:
           is_huffman_encoded: 1
           encoded: "ce31743f"
           decoded: "https"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '02'
       name_index:
           encoded: "02"
           decoded: 2
       value_data_length:
           encoded: "88"
           decoded: 8
       value_data:
           is_huffman_encoded: 1
           encoded: "db6d897a1e44b74f"
           decoded: "www.bar.com"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '1d'
       name_index:
           encoded: "1d"
           decoded: 29
       value_data_length:
           encoded: "86"
           decoded: 6
       value_data:
           is_huffman_encoded: 1
           encoded: "63654a1398ff"
           decoded: "no-cache"

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '83'
       entry_index:
           encoded: "83"
           decoded: 3

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '85'
       entry_index:
           encoded: "85"
           decoded: 5

   # Decoded header set

   The second header
   :authority: www.bar.com
   :method: GET
   :path: /
   :scheme: https
   cache-control: no-cache

   #########################

   # Header set to represent is the following: be encoded
   :method: GET
   :scheme: https
   :path: /my-example/resources/script.js
   user-agent: my-user-agent
   mynewheader: second

   Comparing this second /custom-path.css
   :authority: www.bar.com
   custom-key: custom-value

   # Hexdump of encoded data which will be decoded
   05 8b 04 eb 08 b7 49 5c 88 e6 44 c2 1f 00 88 4e | ......I\..D....N
   b0 8b 74 97 90 fa 7f 89 4e b0 8b 74 97 9a 17 a8 | ..t.....N..t....
   ff 82 86                                        | ...

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '05'
       name_index:
           encoded: "05"
           decoded: 5
       value_data_length:
           encoded: "8b"
           decoded: 11
       value_data:
           is_huffman_encoded: 1
           encoded: "04eb08b7495c88e644c21f"
           decoded: "/custom-path.css"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '00'
       name_index:
           encoded: "00"
           decoded: 0
       name_data_length:
           encoded: "88"
           decoded: 8
       name_data:
           is_huffman_encoded: 1
           encoded: "4eb08b749790fa7f"
           decoded: "custom-key"
       value_data_length:
           encoded: "89"
           decoded: 9
       value_data:

           is_huffman_encoded: 1
           encoded: "4eb08b74979a17a8ff"
           decoded: "custom-value"

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '82'
       entry_index:
           encoded: "82"
           decoded: 2

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '86'
       entry_index:
           encoded: "86"
           decoded: 6

   # Decoded header set to the reference set, the first and
   third headers are from the reference
   :authority: www.bar.com
   :method: GET
   :path: /custom-path.css
   :scheme: https
   custom-key: custom-value

   #########################

E.2.  Request Decoding Example Without Huffman

   # Header set are not present in this
   second to be encoded
   :method: GET
   :scheme: http
   :path: /
   :authority: www.foo.com

   # Hexdump of encoded data which will be decoded
   02 03 47 45 54 07 04 68 74 74 70 06 01 2f 04 0b | ..GET..http../..
   77 77 77 2e 66 6f 6f 2e 63 6f 6d                | www.foo.com

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '02'
       name_index:

           encoded: "02"
           decoded: 2
       value_data_length:
           encoded: "03"
           decoded: 3
       value_data:
           is_huffman_encoded: 0
           encoded: "474554"
           decoded: "GET"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '07'
       name_index:
           encoded: "07"
           decoded: 7
       value_data_length:
           encoded: "04"
           decoded: 4
       value_data:
           is_huffman_encoded: 0
           encoded: "68747470"
           decoded: "http"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '06'
       name_index:
           encoded: "06"
           decoded: 6
       value_data_length:
           encoded: "01"
           decoded: 1
       value_data:
           is_huffman_encoded: 0
           encoded: "2f"
           decoded: "/"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '04'
       name_index:
           encoded: "04"
           decoded: 4
       value_data_length:
           encoded: "0b"
           decoded: 11
       value_data:

           is_huffman_encoded: 0
           encoded: "7777772e666f6f2e636f6d"
           decoded: "www.foo.com"

   # Decoded header set and must be removed.  In addition, in this new set,
   the first and third headers have
   :authority: www.foo.com
   :method: GET
   :path: /
   :scheme: http

   #########################

   # Header set to be encoded.  The path header is
   represented as a literal header with substitution indexing.  The
   mynewheader encoded
   :method: GET
   :scheme: https
   :path: /
   :authority: www.bar.com
   cache-control: no-cache

   # Hexdump of encoded data which will be represented as a literal header with incremental
   indexing.

   0xa6       (indexed header, index = 38: removal from reference set)
   0xa8       (indexed header, index = 40: removal from reference set)
   0x04       (literal header, substitution indexing, name index = 3)
   0x26       (replaced entry index = 38)
   0x1f       (header value string length = 31)
   /my-example/resources/script.js
   0x5f 0x0a  (literal header, incremental indexing, name index = 40)
   0x06       (header value string length = 6)
   second

   The decoded
   03 05 68 74 74 70 73 02 0b 77 77 77 2e 62 61 72 | ..https..www.bar
   2e 63 6f 6d 1d 08 6e 6f 2d 63 61 63 68 65 83 85 | .com..no-cache..

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '03'
       name_index:
           encoded: "03"
           decoded: 3
       value_data_length:
           encoded: "05"
           decoded: 5
       value_data:
           is_huffman_encoded: 0
           encoded: "6874747073"
           decoded: "https"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '02'
       name_index:
           encoded: "02"
           decoded: 2
       value_data_length:
           encoded: "0b"
           decoded: 11

       value_data:
           is_huffman_encoded: 0
           encoded: "7777772e6261722e636f6d"
           decoded: "www.bar.com"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '1d'
       name_index:
           encoded: "1d"
           decoded: 29
       value_data_length:
           encoded: "08"
           decoded: 8
       value_data:
           is_huffman_encoded: 0
           encoded: "6e6f2d6361636865"
           decoded: "no-cache"

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '83'
       entry_index:
           encoded: "83"
           decoded: 3

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '85'
       entry_index:
           encoded: "85"
           decoded: 5

   # Decoded header table is updated as follow: set
   :authority: www.bar.com
   :method: GET
   :path: /
   :scheme: https
   cache-control: no-cache

   #########################

   # Header table
   +---------+----------------+---------------------------+ set to be encoded
   :method: GET
   :scheme: https
   :path: /custom-path.css
   :authority: www.bar.com
   custom-key: custom-value

   # Hexdump of encoded data which will be decoded
   05 10 2f 63 75 73 74 6f 6d 2d 70 61 74 68 2e 63 | ../custom-path.c
   73 73 00 0a 63 75 73 74 6f 6d 2d 6b 65 79 0c 63 | ss..custom-key.c
   75 73 74 6f 6d 2d 76 61 6c 75 65 82 86          | ustom-value..

   # Decoded opcodes
   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '05'
       name_index:
           encoded: "05"
           decoded: 5
       value_data_length:
           encoded: "10"
           decoded: 16
       value_data:
           is_huffman_encoded: 0
           encoded: "2f637573746f6d2d706174682e637373"
           decoded: "/custom-path.css"

   LITERAL_INCREMENTAL_OPCODE:
           opcodeLengthInBits: 2
           discoveredFromPeekingAtByte: '00'
       name_index:
           encoded: "00"
           decoded: 0
       name_data_length:
           encoded: "0a"
           decoded: 10
       name_data:
           is_huffman_encoded: 0
           encoded: "637573746f6d2d6b6579"
           decoded: "custom-key"
       value_data_length:
           encoded: "0c"
           decoded: 12
       value_data:
           is_huffman_encoded: 0
           encoded: "637573746f6d2d76616c7565"
           decoded: "custom-value"

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '82'
       entry_index:
           encoded: "82"
           decoded: 2

   INDEX_OPCODE:
           opcodeLengthInBits: 1
           discoveredFromPeekingAtByte: '86'
       entry_index:
           encoded: "86"
           decoded: 6

   # Decoded header set
   :authority: www.bar.com
   :method: GET
   :path: /custom-path.css
   :scheme: https
   custom-key: custom-value

   #########################

E.3.  Response Decoding Example With Huffman

# Header set to be encoded
:status: 302
cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

# Hexdump of encoded data which will be decoded
08 82 40 9f 18 86 c3 1b 39 bf 38 7f 22 92 a2 fb | ..@.....9.8."...
a2 03 20 f2 eb cc 0c 49 00 62 d2 43 4c 82 7a 1d | .. ....I.b.CL.z.
2f 91 68 71 cf 3c 32 6e bd 7e 9e 9e 92 6e 7e 32 |  Index /.hq.<2n.~...n~2
55 7d bf                                        | U}.

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '08'
    name_index:
        encoded: "08"
        decoded: 8
    value_data_length:
        encoded: "82"
        decoded: 2
    value_data:
        is_huffman_encoded: 1
        encoded: "409f"
        decoded: "302"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '18'
    name_index:
        encoded: "18"
        decoded: 24
    value_data_length:
        encoded: "86"
        decoded: 6
    value_data:
        is_huffman_encoded: 1
        encoded: "c31b39bf387f"
        decoded: "private"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '22'
    name_index:
        encoded: "22"
        decoded: 34
    value_data_length:
        encoded: "92"
        decoded: 18
    value_data:
        is_huffman_encoded: 1
        encoded: "a2fba20320f2ebcc0c490062d2434c827a1d"
        decoded: "Mon, 21 OCt 2013 20:13:21 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '2f'
    name_index:
        encoded: "2f"
        decoded: 47
    value_data_length:
        encoded: "91"
        decoded: 17
    value_data:
        is_huffman_encoded: 1
        encoded: "6871cf3c326ebd7e9e9e926e7e32557dbf"
        decoded: ": https://www.bar.com"

# Decoded header set
:status: 302
cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

#########################

# Header set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
content-encoding: gzip
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded
04 82 31 1f 03 92 a2 fb a2 03 20 f2 eb cc 0c 49 | ..1....... ....I
00 62 d2 43 4c c2 7a 1d 03 90 e3 9e 78 64 dd 7a | .b.CL.z.....xd.z
fd 3d 3d 24 dc fc 64 aa fb 7f 20 84 e1 fb b3 0f | .==$..d... .....
3d ff ee 02 df 7d fb 36 ed db b7 6e dd bb 76 ed | =....}.6...n..v.
db b7 6e dd bb 76 ed db b7 6e dd bb 76 ed db b7 | ..n..v...n..v...
6e dd bb 76 ed db b7 6e dd bb 76 ed db b7 6e dd | n..v...n..v...n.
bb 76 ed db b7 6e dd bb 76 ed db b7 6e dd bb 76 | .v...n..v...n..v
ed db b7 6e dd bb 7e 3b 69 ec f0 fe 7e 1f d7 f3 | ...n..~;i...~...
d5 fe 7f 7e 5f d7 9f 6f 97 cb bf e9 b7 fb fe bc | ...~_..o........
fb 7c bb fe 9b 7f bf 8f 87 f3 f0 fe bc fc bb 7b | .|.............{
fe 9b 7e 3f d7 9f 6f 97 7f d3 6f f7 f1 fe bb 7e | ..~?..o...o....~
9b 7f bf 8f c7 f9 f0 db 4f 67 f5 e7 db e5 f4 ef | ........Og......
db fd f8 91 a1 3f 1d b4 f6 78 7f 3f 0f eb f9 ea | .....?...x.?....
ff 3f bf 2f eb cf b7 cb e5 df f4 db fd ff 5e 7d | .?./..........^}
be 5d ff 4d bf df c7 c3 f9 f8 7f 5e 7e 5d bd ff | .].M.......^~]..
4d bf 1f eb cf b7 cb bf e9 b7 fb f8 ff 5d bf 4d | M............].M
bf df c7 e3 fc f8 6d a7 b3 fa f3 ed f2 fa 77 ed | ......m.......w.
fe fc 48 d0 9f 8e da 7b 3c 3f 9f 87 f5 fc f5 7f | ..H....{<?......
9f df 97 f5 e7 db e5 f2 ef fa 6d fe ff af 3e df | ..........m...>.
2e ff a6 df ef e3 e1 fc fc 3f af 3f 2e de ff a6 | .........?.?....
df 8f f5 e7 db e5 df f4 db fd fc 7f ae df a6 df | ................
ef e3 f1 fe 7c 36 d3 d9 fd 79 f6 f9 7d 3b f6 ff | ....|6...y..};..
7e 24 68 4f c7 6d 3d 9e 1f cf c3 fa fe 7a bf cf | ~$hO.m=......z..
ef cb fa f3 ed f2 f9 77 fd 36 ff 7f d7 9f 6f 97 | .......w.6....o.
7f d3 6f f7 f1 f0 fe 7e 1f d7 9f 97 6f 7f d3 6f | ..o....~....o..o
c7 fa f3 ed f2 ef fa 6d fe fe 3f d7 6f d3 6f f7 | .......m..?.o.o.
f1 f8 ff 3e 1b 69 ec fe bc fb 7c be 9d fb 7f bf | ...>.i....|.....

12 34 27 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f | .4'..?....?....?
cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf | ....?....?....?.
f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 | ...?....?....?..
fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc | ..?....?....?...
ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff | .?....?....?....
3f cf f3 fc ff 3f cf f3 fc ff 3f cf f0 8d 09 0b | ?....?....?.....
5f d2 37 f0 86 c4 4a 23 ef 0e 70 c7 2b 2f bb 61 | _.7...J#..p.+/.a
7f 85 86 88                                     | ....

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '04'
    name_index:
        encoded: "04"
        decoded: 4
    value_data_length:
        encoded: "82"
        decoded: 2
    value_data:
        is_huffman_encoded: 1
        encoded: "311f"
        decoded: "200"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "92"
        decoded: 18
    value_data:
        is_huffman_encoded: 1
        encoded: "a2fba20320f2ebcc0c490062d2434cc27a1d"
        decoded: "Mon, 21 OCt 2013 20:13:22 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "90"
        decoded: 16
    value_data:

        is_huffman_encoded: 1
        encoded: "e39e7864dd7afd3d3d24dcfc64aafb7f"
        decoded: "https://www.bar.com"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '20'
    name_index:
        encoded: "20"
        decoded: 32
    value_data_length:
        encoded: "84"
        decoded: 4
    value_data:
        is_huffman_encoded: 1
        encoded: "e1fbb30f"
        decoded: "gzip"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '3d'
    name_index:
        encoded: "3d"
        decoded: 61
    value_data_length:
        encoded: "ffee02"
        decoded: 493
    value_data:
        is_huffman_encoded: 1
        encoded: "df7dfb36eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76edd\
bb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddb\
b76eddbb7e3b69ecf0fe7e1fd7f3d5fe7f7e5fd79f6f97cbbfe9b7fbfebcfb7cbbfe9b7\
fbf8f87f3f0febcfcbb7bfe9b7e3fd79f6f977fd36ff7f1febb7e9b7fbf8fc7f9f0db4f\
67f5e7dbe5f4efdbfdf891a13f1db4f6787f3f0febf9eaff3fbf2febcfb7cbe5dff4dbf\
dff5e7dbe5dff4dbfdfc7c3f9f87f5e7e5dbdff4dbf1febcfb7cbbfe9b7fbf8ff5dbf4d\
bfdfc7e3fcf86da7b3faf3edf2fa77edfefc48d09f8eda7b3c3f9f87f5fcf57f9fdf97f\
5e7dbe5f2effa6dfeffaf3edf2effa6dfefe3e1fcfc3faf3f2edeffa6df8ff5e7dbe5df\
f4dbfdfc7faedfa6dfefe3f1fe7c36d3d9fd79f6f97d3bf6ff7e24684fc76d3d9e1fcfc\
3fafe7abfcfefcbfaf3edf2f977fd36ff7fd79f6f977fd36ff7f1f0fe7e1fd79f976f7f\
d36fc7faf3edf2effa6dfefe3fd76fd36ff7f1f8ff3e1b69ecfebcfb7cbe9dfb7fbf123\
427fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcf\
f3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff\
3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff08d090b5fd237f086c44a23ef0e70c7\
2b2fbb617f"
        decoded: "foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\
IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '85'
    entry_index:
        encoded: "85"
        decoded: 5

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '86'
    entry_index:
        encoded: "86"
        decoded: 6

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '88'
    entry_index:
        encoded: "88"
        decoded: 8

# Decoded header set
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

#########################

# Header Name set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
content-encoding: gzip
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded
01 ff ee 02 df 7d fb 3f cf f3 fc ff 3f cf f3 fc | .....}.?....?...
ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff | .?....?....?....
3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f | ?....?....?....?
cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf | ....?....?....?.
f3 fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 | ...?....?....?..
fc ff 3f cf f3 fc ff 3f cf f3 fc ff 3f cf f3 fc | ..?....?....?...
ff 3e 3b 69 ec f0 fe 7e 1f d7 f3 d5 fe 7f 7e 5f | .>;i...~......~_
d7 9f 6f 97 cb bf e9 b7 fb fe bc fb 7c bb fe 9b | ..o.........|...
7f bf 8f 87 f3 f0 fe bc fc bb 7b fe 9b 7e 3f d7 | ..........{..~?.
9f 6f 97 7f d3 6f f7 f1 fe bb 7e 9b 7f bf 8f c7 | .o...o....~.....
f9 f0 db 4f 67 f5 e7 db e5 f4 ef db fd f8 91 a1 | ...Og...........
3f 1d b4 f6 78 7f 3f 0f eb f9 ea ff 3f bf 2f eb | ?...x.?.....?./.
cf b7 cb e5 df f4 db fd ff 5e 7d be 5d ff 4d bf | .........^}.].M.
df c7 c3 f9 f8 7f 5e 7e 5d bd ff 4d bf 1f eb cf | ......^~]..M....
b7 cb bf e9 b7 fb f8 ff 5d bf 4d bf df c7 e3 fc | ........].M.....
f8 6d a7 b3 fa f3 ed f2 fa 77 ed fe fc 48 d0 9f | .m.......w...H..
8e da 7b 3c 3f 9f 87 f5 fc f5 7f 9f df 97 f5 e7 | ..{<?...........
db e5 f2 ef fa 6d fe ff af 3e df 2e ff a6 df ef | .....m...>......
e3 e1 fc fc 3f af 3f 2e de ff a6 df 8f f5 e7 db | ....?.?.........
e5 df f4 db fd fc 7f ae df a6 df ef e3 f1 fe 7c | ...............|
36 d3 d9 fd 79 f6 f9 7d 3b f6 ff 7e 24 68 4f c7 | 6...y..};..~$hO.
6d 3d 9e 1f cf c3 fa fe 7a bf cf ef cb fa f3 ed | m=......z.......
f2 f9 77 fd 36 ff 7f d7 9f 6f 97 7f d3 6f f7 f1 | ..w.6....o...o..
f0 fe 7e 1f d7 9f 97 6f 7f d3 6f c7 fa f3 ed f2 | ..~....o..o.....
ef fa 6d fe fe 3f d7 6f d3 6f f7 f1 f8 ff 3e 1b | ..m..?.o.o....>.
69 ec fe bc fb 7c be 9d fb 7f bf 12 34 27 6e dd | i....|......4'n.
bb 76 ed db b7 6e dd bb 76 ed db b7 6e dd bb 76 | .v...n..v...n..v
ed db b7 6e dd bb 76 ed db b7 6e dd bb 76 ed db | ...n..v...n..v..
b7 6e dd bb 76 ed db b7 6e dd bb 76 ed db b7 6e | .n..v...n..v...n
dd bb 76 ed db b7 6e dd bb 76 ed db b4 8d 09 0b | ..v...n..v......
5f d2 37 f0 86 c4 4a 23 ef 0e 70 c7 2b 2f bb 61 | _.7...J#..p.+/.a
7f 81                                           | ..

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '01'
    name_index:

        encoded: "01"
        decoded: 1
    value_data_length:
        encoded: "ffee02"
        decoded: 493
    value_data:
        is_huffman_encoded: 1
        encoded: "df7dfb3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3f\
cff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fc\
ff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3fcff3e3b69ecf\
0fe7e1fd7f3d5fe7f7e5fd79f6f97cbbfe9b7fbfebcfb7cbbfe9b7fbf8f87f3f0febcfc\
bb7bfe9b7e3fd79f6f977fd36ff7f1febb7e9b7fbf8fc7f9f0db4f67f5e7dbe5f4efdbf\
df891a13f1db4f6787f3f0febf9eaff3fbf2febcfb7cbe5dff4dbfdff5e7dbe5dff4dbf\
dfc7c3f9f87f5e7e5dbdff4dbf1febcfb7cbbfe9b7fbf8ff5dbf4dbfdfc7e3fcf86da7b\
3faf3edf2fa77edfefc48d09f8eda7b3c3f9f87f5fcf57f9fdf97f5e7dbe5f2effa6dfe\
ffaf3edf2effa6dfefe3e1fcfc3faf3f2edeffa6df8ff5e7dbe5dff4dbfdfc7faedfa6d\
fefe3f1fe7c36d3d9fd79f6f97d3bf6ff7e24684fc76d3d9e1fcfc3fafe7abfcfefcbfa\
f3edf2f977fd36ff7fd79f6f977fd36ff7f1f0fe7e1fd79f976f7fd36fc7faf3edf2eff\
a6dfefe3fd76fd36ff7f1f8ff3e1b69ecfebcfb7cbe9dfb7fbf1234276eddbb76eddbb7\
6eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76eddbb76\
eddbb76eddbb76eddbb76eddbb76eddbb76eddbb48d090b5fd237f086c44a23ef0e70c7\
2b2fbb617f"
        decoded: "foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\
IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '81'
    entry_index:
        encoded: "81"
        decoded: 1

# Decoded header set
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

#########################

E.4.  Response Decoding Example Without Huffman

# Header Value set to be encoded
:status: 302
cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

# Hexdump of encoded data which will be decoded
08 03 33 30 32 18 07 70 72 69 76 61 74 65 22 1d |
   +---------+----------------+---------------------------+ ..302..private".
4d 6f 6e 2c 20 32 31 20 4f 43 74 20 32 30 31 33 |    0 Mon, 21 OCt 2013
20 32 30 3a 31 33 3a 32 31 20 47 4d 54 2f 15 3a | :scheme  20:13:21 GMT/.:
20 68 74 74 70 73 3a 2f 2f 77 77 77 2e 62 61 72 |  https://www.bar
2e 63 6f 6d                                     | .com

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '08'
    name_index:
        encoded: "08"
        decoded: 8
    value_data_length:
        encoded: "03"
        decoded: 3
    value_data:
        is_huffman_encoded: 0
        encoded: "333032"
        decoded: "302"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '18'
    name_index:
        encoded: "18"
        decoded: 24
    value_data_length:
        encoded: "07"
        decoded: 7
    value_data:
        is_huffman_encoded: 0
        encoded: "70726976617465"
        decoded: "private"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '22'
    name_index:
        encoded: "22"
        decoded: 34
    value_data_length:
        encoded: "1d"
        decoded: 29
    value_data:
        is_huffman_encoded: 0
        encoded: "4d6f6e2c203231204f437420323031332032303a31333a3231204\
74d54"
        decoded: "Mon, 21 OCt 2013 20:13:21 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '2f'
    name_index:
        encoded: "2f"
        decoded: 47
    value_data_length:
        encoded: "15"
        decoded: 21
    value_data:
        is_huffman_encoded: 0
        encoded: "3a2068747470733a2f2f7777772e6261722e636f6d"
        decoded: ": https://www.bar.com"

# Decoded header set
:status: 302
cache-control: private
date: Mon, 21 OCt 2013 20:13:21 GMT
location: : https://www.bar.com

#########################

# Header set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
content-encoding: gzip
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded
04 03 32 30 30 03 1d 4d 6f 6e 2c 20 32 31 20 4f | http ..200..Mon, 21 O
43 74 20 32 30 31 33 20 32 30 3a 31 33 3a 32 32 |
   +---------+----------------+---------------------------+ Ct 2013 20:13:22
20 47 4d 54 03 13 68 74 74 70 73 3a 2f 2f 77 77 |  GMT..https://ww
77 2e 62 61 72 2e 63 6f 6d 20 04 67 7a 69 70 3d | w.bar.com .gzip=
7f e1 02 66 6f 6f 3d 41 41 41 41 41 41 41 41 41 |    1 ...foo=AAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | :scheme AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | https AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 |
   +---------+----------------+---------------------------+ AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 4c |   ... AAAAAAAAAAAAAAAL
41 53 44 4a 4b 48 51 4b 42 5a 58 4f 51 57 45 4f | ASDJKHQKBZXOQWEO
50 49 55 41 58 51 57 45 4f 49 55 41 58 4c 4a 4b | PIUAXQWEOIUAXLJK
48 51 57 4f 45 49 55 41 4c 51 57 45 4f 49 55 41 | ... HQWOEIUALQWEOIUA
58 4c 51 45 55 41 58 4c 4c 4b 4a 41 53 44 51 57 | XLQEUAXLLKJASDQW
45 4f 55 49 41 58 4e 31 32 33 34 4c 41 53 44 4a | EOUIAXN1234LASDJ
4b 48 51 4b 42 5a 58 4f 51 57 45 4f 50 49 55 41 | ... KHQKBZXOQWEOPIUA
58 51 57 45 4f 49 55 41 58 4c 4a 4b 48 51 57 4f | XQWEOIUAXLJKHQWO
45 49 55 41 4c 51 57 45 4f 49 55 41 58 4c 51 45 |
   +---------+----------------+---------------------------+ EIUALQWEOIUAXLQE
55 41 58 4c 4c 4b 4a 41 53 44 51 57 45 4f 55 49 |   37 UAXLLKJASDQWEOUI
41 58 4e 31 32 33 34 4c 41 53 44 4a 4b 48 51 4b | AXN1234LASDJKHQK
42 5a 58 4f 51 57 45 4f 50 49 55 41 58 51 57 45 | BZXOQWEOPIUAXQWE
4f 49 55 41 58 4c 4a 4b 48 51 57 4f 45 49 55 41 | warning OIUAXLJKHQWOEIUA
4c 51 57 45 4f 49 55 41 58 4c 51 45 55 41 58 4c | LQWEOIUAXLQEUAXL
4c 4b 4a 41 53 44 51 57 45 4f 55 49 41 58 4e 31 |
   +---------+----------------+---------------------------+ LKJASDQWEOUIAXN1
32 33 34 4c 41 53 44 4a 4b 48 51 4b 42 5a 58 4f | 234LASDJKHQKBZXO
51 57 45 4f 50 49 55 41 58 51 57 45 4f 49 55 41 |   38 QWEOPIUAXQWEOIUA
58 4c 4a 4b 48 51 57 4f 45 49 55 41 4c 51 57 45 | XLJKHQWOEIUALQWE
4f 49 55 41 58 4c 51 45 55 41 58 4c 4c 4b 4a 41 | :path OIUAXLQEUAXLLKJA
53 44 51 57 45 4f 55 49 41 58 4e 31 32 33 34 5a | SDQWEOUIAXN1234Z
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 31 32 33 34 20 6d 61 78 2d | /my-example/resources/ ZZZZZZZ1234 max-
61 67 65 3d 33 36 30 30 3b 20 76 65 72 73 69 6f | age=3600; versio
6e 3d 31 85 86 88                               | n=1...

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '04'
    name_index:
        encoded: "04"
        decoded: 4
    value_data_length:
        encoded: "03"
        decoded: 3
    value_data:
        is_huffman_encoded: 0
        encoded: "323030"
        decoded: "200"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "1d"
        decoded: 29
    value_data:
        is_huffman_encoded: 0
        encoded: "4d6f6e2c203231204f437420323031332032303a31333a3232204\
74d54"
        decoded: "Mon, 21 OCt 2013 20:13:22 GMT"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '03'
    name_index:
        encoded: "03"
        decoded: 3
    value_data_length:
        encoded: "13"
        decoded: 19
    value_data:
        is_huffman_encoded: 0
        encoded: "68747470733a2f2f7777772e6261722e636f6d"
        decoded: "https://www.bar.com"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '20'
    name_index:
        encoded: "20"
        decoded: 32
    value_data_length:
        encoded: "04"
        decoded: 4
    value_data:
        is_huffman_encoded: 0
        encoded: "677a6970"
        decoded: "gzip"

LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '3d'
    name_index:
        encoded: "3d"
        decoded: 61
    value_data_length:
        encoded: "7fe102"
        decoded: 480
    value_data:
        is_huffman_encoded: 0
        encoded: "666f6f3d414141414141414141414141414141414141414141414\
14141414141414141414141414141414141414141414141414141414141414141414141\
41414141414141414141414141414c4153444a4b48514b425a584f5157454f504955415\
85157454f495541584c4a4b4851574f454955414c5157454f495541584c51455541584c\
4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a584f5157454\
f50495541585157454f495541584c4a4b4851574f454955414c5157454f495541584c51\
455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a5\
84f5157454f50495541585157454f495541584c4a4b4851574f454955414c5157454f49\
5541584c51455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b4\
8514b425a584f5157454f50495541585157454f495541584c4a4b4851574f454955414c\
5157454f495541584c51455541584c4c4b4a4153445157454f554941584e313233345a5\
a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a\
5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a3\
1323334206d61782d6167653d333630303b2076657273696f6e3d31"
        decoded: "foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\
IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '85'
    entry_index:
        encoded: "85"
        decoded: 5

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '86'
    entry_index:
        encoded: "86"
        decoded: 6

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '88'
    entry_index:
        encoded: "88"
        decoded: 8

# Decoded header set
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAALASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ1234 max-age=3600; version=1

#########################

# Header set to be encoded
:status: 200
cache-control: private
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
content-encoding: gzip
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

# Hexdump of encoded data which will be decoded
01 7f e1 02 66 6f 6f 3d 5a 5a 5a 5a 5a 5a 5a 5a | ....foo=ZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | ZZZZZZZZZZZZZZZZ
5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a | replaced ZZZZZZZZZZZZZZZZ
4c 41 53 44 4a 4b 48 51 4b 42 5a 58 4f 51 57 45 | LASDJKHQKBZXOQWE
4f 50 49 55 41 58 51 57 45 4f 49 55 41 58 4c 4a | OPIUAXQWEOIUAXLJ
4b 48 51 57 4f 45 49 55 41 4c 51 57 45 4f 49 55 | KHQWOEIUALQWEOIU
41 58 4c 51 45 55 41 58 4c 4c 4b 4a 41 53 44 51 | AXLQEUAXLLKJASDQ
57 45 4f 55 49 41 58 4e 31 32 33 34 4c 41 53 44 | WEOUIAXN1234LASD
4a 4b 48 51 4b 42 5a 58 4f 51 57 45 4f 50 49 55 |     script.js JKHQKBZXOQWEOPIU
41 58 51 57 45 4f 49 55 41 58 4c 4a 4b 48 51 57 | AXQWEOIUAXLJKHQW
4f 45 49 55 41 4c 51 57 45 4f 49 55 41 58 4c 51 | OEIUALQWEOIUAXLQ
45 55 41 58 4c 4c 4b 4a 41 53 44 51 57 45 4f 55 | header
   +---------+----------------+---------------------------+ EUAXLLKJASDQWEOU
49 41 58 4e 31 32 33 34 4c 41 53 44 4a 4b 48 51 | IAXN1234LASDJKHQ
4b 42 5a 58 4f 51 57 45 4f 50 49 55 41 58 51 57 | KBZXOQWEOPIUAXQW
45 4f 49 55 41 58 4c 4a 4b 48 51 57 4f 45 49 55 |   39 EOIUAXLJKHQWOEIU
41 4c 51 57 45 4f 49 55 41 58 4c 51 45 55 41 58 | user-agent ALQWEOIUAXLQEUAX
4c 4c 4b 4a 41 53 44 51 57 45 4f 55 49 41 58 4e | my-user-agent LLKJASDQWEOUIAXN
31 32 33 34 4c 41 53 44 4a 4b 48 51 4b 42 5a 58 | 1234LASDJKHQKBZX
4f 51 57 45 4f 50 49 55 41 58 51 57 45 4f 49 55 |
   +---------+----------------+---------------------------+ OQWEOPIUAXQWEOIU
41 58 4c 4a 4b 48 51 57 4f 45 49 55 41 4c 51 57 | AXLJKHQWOEIUALQW
45 4f 49 55 41 58 4c 51 45 55 41 58 4c 4c 4b 4a |   40 EOIUAXLQEUAXLLKJ
41 53 44 51 57 45 4f 55 49 41 58 4e 31 32 33 34 | mynewheader ASDQWEOUIAXN1234
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | first AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 |
   +---------+----------------+---------------------------+ AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 41 | mynewheader AAAAAAAAAAAAAAAA
41 41 41 41 41 41 41 41 31 32 33 34 20 6d 61 78 | second AAAAAAAA1234 max
2d 61 67 65 3d 33 36 30 30 3b 20 76 65 72 73 69 | -age=3600; versi
6f 6e 3d 31 81                                  | added header
   +---------+----------------+---------------------------+

   All the headers in this second header set are indexed in the on=1.

# Decoded opcodes
LITERAL_INCREMENTAL_OPCODE:
        opcodeLengthInBits: 2
        discoveredFromPeekingAtByte: '01'
    name_index:
        encoded: "01"
        decoded: 1
    value_data_length:
        encoded: "7fe102"
        decoded: 480
    value_data:
        is_huffman_encoded: 0
        encoded: "666f6f3d5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5\
a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a5a\
5a5a5a5a5a5a5a5a5a5a5a5a5a5a4c4153444a4b48514b425a584f5157454f504955415\
85157454f495541584c4a4b4851574f454955414c5157454f495541584c51455541584c\
4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a584f5157454\
f50495541585157454f495541584c4a4b4851574f454955414c5157454f495541584c51\
455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b48514b425a5\
84f5157454f50495541585157454f495541584c4a4b4851574f454955414c5157454f49\
5541584c51455541584c4c4b4a4153445157454f554941584e313233344c4153444a4b4\
8514b425a584f5157454f50495541585157454f495541584c4a4b4851574f454955414c\
5157454f495541584c51455541584c4c4b4a4153445157454f554941584e31323334414\
14141414141414141414141414141414141414141414141414141414141414141414141\
41414141414141414141414141414141414141414141414141414141414141414141413\
1323334206d61782d6167653d333630303b2076657273696f6e3d31"
        decoded: "foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIU\
AXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQ\
WEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOE\
IUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJK\
HQWOEIUALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234max-age=3600; version=1\
"

INDEX_OPCODE:
        opcodeLengthInBits: 1
        discoveredFromPeekingAtByte: '81'
    entry_index:
        encoded: "81"
        decoded: 1

# Decoded header
   table, therefore, all are kept in the reference set of headers, which
   becomes:

   Reference Set:
   :path, /my-example/resources/script.js
   user-agent, my-user-agent
   mynewheader, second
:status: 200
cache-control: private
content-encoding: gzip
date: Mon, 21 OCt 2013 20:13:22 GMT
location: https://www.bar.com
set-cookie: foo=ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ\
ZZZZZZZZZZZZZZZZZLASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUAXLQEU\
AXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQWEOIUA\
XLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEIUALQW\
EOIUAXLQEUAXLLKJASDQWEOUIAXN1234LASDJKHQKBZXOQWEOPIUAXQWEOIUAXLJKHQWOEI\
UALQWEOIUAXLQEUAXLLKJASDQWEOUIAXN1234AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA\
AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA1234 max-age=3600; version=1

#########################
Authors' Addresses

   Roberto Peon
   Google, Inc

   EMail: fenix@google.com

   Herve Ruellan
   Canon CRF

   EMail: herve.ruellan@crf.canon.fr