[mirror_edk2.git] / BaseTools / Source / C / BrotliCompress / common / context.h

/* Copyright 2013 Google Inc. All Rights Reserved.\r
\r
   Distributed under MIT license.\r
   See file LICENSE for detail or copy at https://opensource.org/licenses/MIT\r
*/\r
\r
/* Lookup table to map the previous two bytes to a context id.\r
\r
  There are four different context modeling modes defined here:\r
    CONTEXT_LSB6: context id is the least significant 6 bits of the last byte,\r
    CONTEXT_MSB6: context id is the most significant 6 bits of the last byte,\r
    CONTEXT_UTF8: second-order context model tuned for UTF8-encoded text,\r
    CONTEXT_SIGNED: second-order context model tuned for signed integers.\r
\r
  If |p1| and |p2| are the previous two bytes, and |mode| is current context\r
  mode, we calculate the context as:\r
\r
    context = ContextLut(mode)[p1] | ContextLut(mode)[p2 + 256].\r
\r
  For CONTEXT_UTF8 mode, if the previous two bytes are ASCII characters\r
  (i.e. < 128), this will be equivalent to\r
\r
    context = 4 * context1(p1) + context2(p2),\r
\r
  where context1 is based on the previous byte in the following way:\r
\r
    0  : non-ASCII control\r
    1  : \t, \n, \r\r
    2  : space\r
    3  : other punctuation\r
    4  : " '\r
    5  : %\r
    6  : ( < [ {\r
    7  : ) > ] }\r
    8  : , ; :\r
    9  : .\r
    10 : =\r
    11 : number\r
    12 : upper-case vowel\r
    13 : upper-case consonant\r
    14 : lower-case vowel\r
    15 : lower-case consonant\r
\r
  and context2 is based on the second last byte:\r
\r
    0 : control, space\r
    1 : punctuation\r
    2 : upper-case letter, number\r
    3 : lower-case letter\r
\r
  If the last byte is ASCII, and the second last byte is not (in a valid UTF8\r
  stream it will be a continuation byte, value between 128 and 191), the\r
  context is the same as if the second last byte was an ASCII control or space.\r
\r
  If the last byte is a UTF8 lead byte (value >= 192), then the next byte will\r
  be a continuation byte and the context id is 2 or 3 depending on the LSB of\r
  the last byte and to a lesser extent on the second last byte if it is ASCII.\r
\r
  If the last byte is a UTF8 continuation byte, the second last byte can be:\r
    - continuation byte: the next byte is probably ASCII or lead byte (assuming\r
      4-byte UTF8 characters are rare) and the context id is 0 or 1.\r
    - lead byte (192 - 207): next byte is ASCII or lead byte, context is 0 or 1\r
    - lead byte (208 - 255): next byte is continuation byte, context is 2 or 3\r
\r
  The possible value combinations of the previous two bytes, the range of\r
  context ids and the type of the next byte is summarized in the table below:\r
\r
  |--------\-----------------------------------------------------------------|\r
  |         \                         Last byte                              |\r
  | Second   \---------------------------------------------------------------|\r
  | last byte \    ASCII            |   cont. byte        |   lead byte      |\r
  |            \   (0-127)          |   (128-191)         |   (192-)         |\r
  |=============|===================|=====================|==================|\r
  |  ASCII      | next: ASCII/lead  |  not valid          |  next: cont.     |\r
  |  (0-127)    | context: 4 - 63   |                     |  context: 2 - 3  |\r
  |-------------|-------------------|---------------------|------------------|\r
  |  cont. byte | next: ASCII/lead  |  next: ASCII/lead   |  next: cont.     |\r
  |  (128-191)  | context: 4 - 63   |  context: 0 - 1     |  context: 2 - 3  |\r
  |-------------|-------------------|---------------------|------------------|\r
  |  lead byte  | not valid         |  next: ASCII/lead   |  not valid       |\r
  |  (192-207)  |                   |  context: 0 - 1     |                  |\r
  |-------------|-------------------|---------------------|------------------|\r
  |  lead byte  | not valid         |  next: cont.        |  not valid       |\r
  |  (208-)     |                   |  context: 2 - 3     |                  |\r
  |-------------|-------------------|---------------------|------------------|\r
*/\r
\r
#ifndef BROTLI_COMMON_CONTEXT_H_\r
#define BROTLI_COMMON_CONTEXT_H_\r
\r
#include <brotli/types.h>\r
\r
typedef enum ContextType {\r
  CONTEXT_LSB6 = 0,\r
  CONTEXT_MSB6 = 1,\r
  CONTEXT_UTF8 = 2,\r
  CONTEXT_SIGNED = 3\r
} ContextType;\r
\r
/* Common context lookup table for all context modes. */\r
static const uint8_t kContextLookup[2048] = {\r
  /* CONTEXT_LSB6, last byte. */\r
   0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,\r
  16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,\r
  32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,\r
  48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,\r
   0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,\r
  16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,\r
  32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,\r
  48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,\r
   0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,\r
  16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,\r
  32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,\r
  48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,\r
   0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15,\r
  16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,\r
  32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,\r
  48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,\r
\r
  /* CONTEXT_LSB6, second last byte, */\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
\r
  /* CONTEXT_MSB6, last byte. */\r
   0,  0,  0,  0,  1,  1,  1,  1,  2,  2,  2,  2,  3,  3,  3,  3,\r
   4,  4,  4,  4,  5,  5,  5,  5,  6,  6,  6,  6,  7,  7,  7,  7,\r
   8,  8,  8,  8,  9,  9,  9,  9, 10, 10, 10, 10, 11, 11, 11, 11,\r
  12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15,\r
  16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19,\r
  20, 20, 20, 20, 21, 21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23,\r
  24, 24, 24, 24, 25, 25, 25, 25, 26, 26, 26, 26, 27, 27, 27, 27,\r
  28, 28, 28, 28, 29, 29, 29, 29, 30, 30, 30, 30, 31, 31, 31, 31,\r
  32, 32, 32, 32, 33, 33, 33, 33, 34, 34, 34, 34, 35, 35, 35, 35,\r
  36, 36, 36, 36, 37, 37, 37, 37, 38, 38, 38, 38, 39, 39, 39, 39,\r
  40, 40, 40, 40, 41, 41, 41, 41, 42, 42, 42, 42, 43, 43, 43, 43,\r
  44, 44, 44, 44, 45, 45, 45, 45, 46, 46, 46, 46, 47, 47, 47, 47,\r
  48, 48, 48, 48, 49, 49, 49, 49, 50, 50, 50, 50, 51, 51, 51, 51,\r
  52, 52, 52, 52, 53, 53, 53, 53, 54, 54, 54, 54, 55, 55, 55, 55,\r
  56, 56, 56, 56, 57, 57, 57, 57, 58, 58, 58, 58, 59, 59, 59, 59,\r
  60, 60, 60, 60, 61, 61, 61, 61, 62, 62, 62, 62, 63, 63, 63, 63,\r
\r
  /* CONTEXT_MSB6, second last byte, */\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
\r
  /* CONTEXT_UTF8, last byte. */\r
  /* ASCII range. */\r
   0,  0,  0,  0,  0,  0,  0,  0,  0,  4,  4,  0,  0,  4,  0,  0,\r
   0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,\r
   8, 12, 16, 12, 12, 20, 12, 16, 24, 28, 12, 12, 32, 12, 36, 12,\r
  44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 32, 32, 24, 40, 28, 12,\r
  12, 48, 52, 52, 52, 48, 52, 52, 52, 48, 52, 52, 52, 52, 52, 48,\r
  52, 52, 52, 52, 52, 48, 52, 52, 52, 52, 52, 24, 12, 28, 12, 12,\r
  12, 56, 60, 60, 60, 56, 60, 60, 60, 56, 60, 60, 60, 60, 60, 56,\r
  60, 60, 60, 60, 60, 56, 60, 60, 60, 60, 60, 24, 12, 28, 12,  0,\r
  /* UTF8 continuation byte range. */\r
  0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,\r
  0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,\r
  0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,\r
  0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,\r
  /* UTF8 lead byte range. */\r
  2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,\r
  2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,\r
  2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,\r
  2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,\r
\r
  /* CONTEXT_UTF8 second last byte. */\r
  /* ASCII range. */\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,\r
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1,\r
  1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1,\r
  1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,\r
  3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, 0,\r
  /* UTF8 continuation byte range. */\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  /* UTF8 lead byte range. */\r
  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
\r
  /* CONTEXT_SIGNED, last byte, same as the above values shifted by 3 bits. */\r
   0, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,\r
  16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,\r
  16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,\r
  16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,\r
  24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,\r
  24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,\r
  24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,\r
  24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,\r
  32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,\r
  32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,\r
  32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,\r
  32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,\r
  40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,\r
  40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,\r
  40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,\r
  48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 56,\r
\r
  /* CONTEXT_SIGNED, second last byte. */\r
  0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,\r
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
  2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
  3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,\r
  3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,\r
  3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,\r
  3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,\r
  4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,\r
  4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,\r
  4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,\r
  4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,\r
  5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,\r
  5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,\r
  5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,\r
  6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7,\r
};\r
\r
typedef const uint8_t* ContextLut;\r
\r
/* typeof(MODE) == ContextType; returns ContextLut */\r
#define BROTLI_CONTEXT_LUT(MODE) (&kContextLookup[(MODE) << 9])\r
\r
/* typeof(LUT) == ContextLut */\r
#define BROTLI_CONTEXT(P1, P2, LUT) ((LUT)[P1] | ((LUT) + 256)[P2])\r
\r
#endif  /* BROTLI_COMMON_CONTEXT_H_ */\r
Commit	Line	Data
11b7501a SB	1	/* Copyright 2013 Google Inc. All Rights Reserved.\r
	2	\r
	3	Distributed under MIT license.\r
	4	See file LICENSE for detail or copy at https://opensource.org/licenses/MIT\r
	5	*/\r
	6	\r
	7	/* Lookup table to map the previous two bytes to a context id.\r
	8	\r
dd4f667e LG	9	There are four different context modeling modes defined here:\r
	10	CONTEXT_LSB6: context id is the least significant 6 bits of the last byte,\r
	11	CONTEXT_MSB6: context id is the most significant 6 bits of the last byte,\r
	12	CONTEXT_UTF8: second-order context model tuned for UTF8-encoded text,\r
	13	CONTEXT_SIGNED: second-order context model tuned for signed integers.\r
	14	\r
	15	If \|p1\| and \|p2\| are the previous two bytes, and \|mode\| is current context\r
	16	mode, we calculate the context as:\r
	17	\r
	18	context = ContextLut(mode)[p1] \| ContextLut(mode)[p2 + 256].\r
	19	\r
	20	For CONTEXT_UTF8 mode, if the previous two bytes are ASCII characters\r
	21	(i.e. < 128), this will be equivalent to\r
	22	\r
	23	context = 4 * context1(p1) + context2(p2),\r
	24	\r
	25	where context1 is based on the previous byte in the following way:\r
	26	\r
	27	0 : non-ASCII control\r
	28	1 : \t, \n, \r\r
	29	2 : space\r
	30	3 : other punctuation\r
	31	4 : " '\r
	32	5 : %\r
	33	6 : ( < [ {\r
	34	7 : ) > ] }\r
	35	8 : , ; :\r
	36	9 : .\r
	37	10 : =\r
	38	11 : number\r
	39	12 : upper-case vowel\r
	40	13 : upper-case consonant\r
	41	14 : lower-case vowel\r
	42	15 : lower-case consonant\r
	43	\r
	44	and context2 is based on the second last byte:\r
	45	\r
	46	0 : control, space\r
	47	1 : punctuation\r
	48	2 : upper-case letter, number\r
	49	3 : lower-case letter\r
	50	\r
	51	If the last byte is ASCII, and the second last byte is not (in a valid UTF8\r
	52	stream it will be a continuation byte, value between 128 and 191), the\r
	53	context is the same as if the second last byte was an ASCII control or space.\r
	54	\r
	55	If the last byte is a UTF8 lead byte (value >= 192), then the next byte will\r
	56	be a continuation byte and the context id is 2 or 3 depending on the LSB of\r
	57	the last byte and to a lesser extent on the second last byte if it is ASCII.\r
	58	\r
	59	If the last byte is a UTF8 continuation byte, the second last byte can be:\r
	60	- continuation byte: the next byte is probably ASCII or lead byte (assuming\r
	61	4-byte UTF8 characters are rare) and the context id is 0 or 1.\r
	62	- lead byte (192 - 207): next byte is ASCII or lead byte, context is 0 or 1\r
	63	- lead byte (208 - 255): next byte is continuation byte, context is 2 or 3\r
	64	\r
	65	The possible value combinations of the previous two bytes, the range of\r
	66	context ids and the type of the next byte is summarized in the table below:\r
	67	\r
	68	\|--------\-----------------------------------------------------------------\|\r
	69	\| \ Last byte \|\r
	70	\| Second \---------------------------------------------------------------\|\r
	71	\| last byte \ ASCII \| cont. byte \| lead byte \|\r
	72	\| \ (0-127) \| (128-191) \| (192-) \|\r
73	\|=============\|===================\|=====================\|==================\|\r
74	\| ASCII \| next: ASCII/lead \| not valid \| next: cont. \|\r
75	\| (0-127) \| context: 4 - 63 \| \| context: 2 - 3 \|\r
76	\|-------------\|-------------------\|---------------------\|------------------\|\r
77	\| cont. byte \| next: ASCII/lead \| next: ASCII/lead \| next: cont. \|\r
78	\| (128-191) \| context: 4 - 63 \| context: 0 - 1 \| context: 2 - 3 \|\r
79	\|-------------\|-------------------\|---------------------\|------------------\|\r
80	\| lead byte \| not valid \| next: ASCII/lead \| not valid \|\r
81	\| (192-207) \| \| context: 0 - 1 \| \|\r
82	\|-------------\|-------------------\|---------------------\|------------------\|\r
83	\| lead byte \| not valid \| next: cont. \| not valid \|\r
84	\| (208-) \| \| context: 2 - 3 \| \|\r
85	\|-------------\|-------------------\|---------------------\|------------------\|\r
11b7501a SB	86	*/\r
11b7501a SB	87	\r
dd4f667e LG	88	#ifndef BROTLI_COMMON_CONTEXT_H_\r
dd4f667e LG	89	#define BROTLI_COMMON_CONTEXT_H_\r
11b7501a	90	\r
dd4f667e	91	#include <brotli/types.h>\r
11b7501a	92	\r
dd4f667e	93	typedef enum ContextType {\r
11b7501a SB	94	CONTEXT_LSB6 = 0,\r
	95	CONTEXT_MSB6 = 1,\r
	96	CONTEXT_UTF8 = 2,\r
	97	CONTEXT_SIGNED = 3\r
dd4f667e	98	} ContextType;\r
11b7501a SB	99	\r
11b7501a SB	100	/* Common context lookup table for all context modes. */\r
dd4f667e LG	101	static const uint8_t kContextLookup[2048] = {\r
	102	/* CONTEXT_LSB6, last byte. */\r
	103	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,\r
	104	16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,\r
	105	32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,\r
	106	48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,\r
	107	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,\r
	108	16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,\r
	109	32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,\r
	110	48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,\r
	111	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,\r
	112	16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,\r
	113	32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,\r
	114	48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,\r
	115	0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,\r
	116	16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31,\r
	117	32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47,\r
	118	48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,\r
	119	\r
	120	/* CONTEXT_LSB6, second last byte, */\r
	121	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	122	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	123	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	124	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	125	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	126	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	127	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	128	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	129	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	130	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	131	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	132	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	133	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	134	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	135	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	136	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	137	\r
	138	/* CONTEXT_MSB6, last byte. */\r
	139	0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3,\r
	140	4, 4, 4, 4, 5, 5, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7,\r
	141	8, 8, 8, 8, 9, 9, 9, 9, 10, 10, 10, 10, 11, 11, 11, 11,\r
	142	12, 12, 12, 12, 13, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15,\r
	143	16, 16, 16, 16, 17, 17, 17, 17, 18, 18, 18, 18, 19, 19, 19, 19,\r
	144	20, 20, 20, 20, 21, 21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23,\r
	145	24, 24, 24, 24, 25, 25, 25, 25, 26, 26, 26, 26, 27, 27, 27, 27,\r
	146	28, 28, 28, 28, 29, 29, 29, 29, 30, 30, 30, 30, 31, 31, 31, 31,\r
	147	32, 32, 32, 32, 33, 33, 33, 33, 34, 34, 34, 34, 35, 35, 35, 35,\r
	148	36, 36, 36, 36, 37, 37, 37, 37, 38, 38, 38, 38, 39, 39, 39, 39,\r
	149	40, 40, 40, 40, 41, 41, 41, 41, 42, 42, 42, 42, 43, 43, 43, 43,\r
	150	44, 44, 44, 44, 45, 45, 45, 45, 46, 46, 46, 46, 47, 47, 47, 47,\r
	151	48, 48, 48, 48, 49, 49, 49, 49, 50, 50, 50, 50, 51, 51, 51, 51,\r
	152	52, 52, 52, 52, 53, 53, 53, 53, 54, 54, 54, 54, 55, 55, 55, 55,\r
	153	56, 56, 56, 56, 57, 57, 57, 57, 58, 58, 58, 58, 59, 59, 59, 59,\r
	154	60, 60, 60, 60, 61, 61, 61, 61, 62, 62, 62, 62, 63, 63, 63, 63,\r
	155	\r
	156	/* CONTEXT_MSB6, second last byte, */\r
	157	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	158	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	159	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	160	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	161	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	162	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	163	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	164	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
165	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
166	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
167	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
168	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
169	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
170	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
171	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
172	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
173	\r
11b7501a SB	174	/* CONTEXT_UTF8, last byte. */\r
	175	/* ASCII range. */\r
	176	0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 0, 4, 0, 0,\r
	177	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	178	8, 12, 16, 12, 12, 20, 12, 16, 24, 28, 12, 12, 32, 12, 36, 12,\r
	179	44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 32, 32, 24, 40, 28, 12,\r
	180	12, 48, 52, 52, 52, 48, 52, 52, 52, 48, 52, 52, 52, 52, 52, 48,\r
	181	52, 52, 52, 52, 52, 48, 52, 52, 52, 52, 52, 24, 12, 28, 12, 12,\r
	182	12, 56, 60, 60, 60, 56, 60, 60, 60, 56, 60, 60, 60, 60, 60, 56,\r
	183	60, 60, 60, 60, 60, 56, 60, 60, 60, 60, 60, 24, 12, 28, 12, 0,\r
	184	/* UTF8 continuation byte range. */\r
	185	0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,\r
	186	0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,\r
	187	0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,\r
	188	0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1,\r
	189	/* UTF8 lead byte range. */\r
	190	2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,\r
	191	2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,\r
	192	2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,\r
	193	2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3,\r
dd4f667e	194	\r
11b7501a SB	195	/* CONTEXT_UTF8 second last byte. */\r
	196	/* ASCII range. */\r
	197	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	198	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	199	0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,\r
	200	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1,\r
	201	1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
	202	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1,\r
	203	1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,\r
	204	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, 0,\r
	205	/* UTF8 continuation byte range. */\r
	206	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	207	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	208	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	209	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	210	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	211	/* UTF8 lead byte range. */\r
	212	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,\r
	213	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
	214	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
dd4f667e	215	\r
11b7501a SB	216	/* CONTEXT_SIGNED, last byte, same as the above values shifted by 3 bits. */\r
	217	0, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,\r
	218	16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,\r
	219	16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,\r
	220	16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,\r
	221	24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,\r
	222	24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,\r
	223	24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,\r
	224	24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,\r
	225	32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,\r
	226	32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,\r
	227	32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,\r
	228	32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32,\r
	229	40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,\r
	230	40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,\r
	231	40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40, 40,\r
	232	48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 56,\r
11b7501a	233	\r
dd4f667e LG	234	/* CONTEXT_SIGNED, second last byte. */\r
	235	0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,\r
	236	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
	237	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
	238	2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,\r
	239	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,\r
	240	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,\r
	241	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,\r
	242	3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3,\r
	243	4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,\r
	244	4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,\r
	245	4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,\r
	246	4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,\r
	247	5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,\r
	248	5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,\r
	249	5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,\r
	250	6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7,\r
11b7501a SB	251	};\r
11b7501a SB	252	\r
dd4f667e LG	253	typedef const uint8_t* ContextLut;\r
	254	\r
	255	/* typeof(MODE) == ContextType; returns ContextLut */\r
	256	#define BROTLI_CONTEXT_LUT(MODE) (&kContextLookup[(MODE) << 9])\r
	257	\r
	258	/* typeof(LUT) == ContextLut */\r
	259	#define BROTLI_CONTEXT(P1, P2, LUT) ((LUT)[P1] \| ((LUT) + 256)[P2])\r
	260	\r
	261	#endif /* BROTLI_COMMON_CONTEXT_H_ */\r