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author | Karl Berry <karl@freefriends.org> | 2018-01-17 22:50:15 +0000 |
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committer | Karl Berry <karl@freefriends.org> | 2018-01-17 22:50:15 +0000 |
commit | e7dfe5ab98e759081fc73990ed6c1ac6910a105d (patch) | |
tree | 1635f79c86856a6aa57a45b8b952b651ef9fcba9 /Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/enc/context.h | |
parent | ae542350b1e3add10d4ee3d7b68f610132f31a50 (diff) |
dvisvgm 2.3.1 (patched)
git-svn-id: svn://tug.org/texlive/trunk@46352 c570f23f-e606-0410-a88d-b1316a301751
Diffstat (limited to 'Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/enc/context.h')
-rw-r--r-- | Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/enc/context.h | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/enc/context.h b/Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/enc/context.h new file mode 100644 index 00000000000..0e2e453a4b5 --- /dev/null +++ b/Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/enc/context.h @@ -0,0 +1,184 @@ +/* Copyright 2013 Google Inc. All Rights Reserved. + + Distributed under MIT license. + See file LICENSE for detail or copy at https://opensource.org/licenses/MIT +*/ + +/* Functions to map previous bytes into a context id. */ + +#ifndef BROTLI_ENC_CONTEXT_H_ +#define BROTLI_ENC_CONTEXT_H_ + +#include <brotli/port.h> +#include <brotli/types.h> + +#if defined(__cplusplus) || defined(c_plusplus) +extern "C" { +#endif + +/* Second-order context lookup table for UTF8 byte streams. + + If p1 and p2 are the previous two bytes, we calculate the context as + + context = kUTF8ContextLookup[p1] | kUTF8ContextLookup[p2 + 256]. + + If the previous two bytes are ASCII characters (i.e. < 128), this will be + equivalent to + + context = 4 * context1(p1) + context2(p2), + + where context1 is based on the previous byte in the following way: + + 0 : non-ASCII control + 1 : \t, \n, \r + 2 : space + 3 : other punctuation + 4 : " ' + 5 : % + 6 : ( < [ { + 7 : ) > ] } + 8 : , ; : + 9 : . + 10 : = + 11 : number + 12 : upper-case vowel + 13 : upper-case consonant + 14 : lower-case vowel + 15 : lower-case consonant + + and context2 is based on the second last byte: + + 0 : control, space + 1 : punctuation + 2 : upper-case letter, number + 3 : lower-case letter + + If the last byte is ASCII, and the second last byte is not (in a valid UTF8 + stream it will be a continuation byte, value between 128 and 191), the + context is the same as if the second last byte was an ASCII control or space. + + If the last byte is a UTF8 lead byte (value >= 192), then the next byte will + be a continuation byte and the context id is 2 or 3 depending on the LSB of + the last byte and to a lesser extent on the second last byte if it is ASCII. + + If the last byte is a UTF8 continuation byte, the second last byte can be: + - continuation byte: the next byte is probably ASCII or lead byte (assuming + 4-byte UTF8 characters are rare) and the context id is 0 or 1. + - lead byte (192 - 207): next byte is ASCII or lead byte, context is 0 or 1 + - lead byte (208 - 255): next byte is continuation byte, context is 2 or 3 + + The possible value combinations of the previous two bytes, the range of + context ids and the type of the next byte is summarized in the table below: + + |--------\-----------------------------------------------------------------| + | \ Last byte | + | Second \---------------------------------------------------------------| + | last byte \ ASCII | cont. byte | lead byte | + | \ (0-127) | (128-191) | (192-) | + |=============|===================|=====================|==================| + | ASCII | next: ASCII/lead | not valid | next: cont. | + | (0-127) | context: 4 - 63 | | context: 2 - 3 | + |-------------|-------------------|---------------------|------------------| + | cont. byte | next: ASCII/lead | next: ASCII/lead | next: cont. | + | (128-191) | context: 4 - 63 | context: 0 - 1 | context: 2 - 3 | + |-------------|-------------------|---------------------|------------------| + | lead byte | not valid | next: ASCII/lead | not valid | + | (192-207) | | context: 0 - 1 | | + |-------------|-------------------|---------------------|------------------| + | lead byte | not valid | next: cont. | not valid | + | (208-) | | context: 2 - 3 | | + |-------------|-------------------|---------------------|------------------| +*/ +static const uint8_t kUTF8ContextLookup[512] = { + /* Last byte. */ + /* */ + /* ASCII range. */ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 4, 0, 0, 4, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 8, 12, 16, 12, 12, 20, 12, 16, 24, 28, 12, 12, 32, 12, 36, 12, + 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 32, 32, 24, 40, 28, 12, + 12, 48, 52, 52, 52, 48, 52, 52, 52, 48, 52, 52, 52, 52, 52, 48, + 52, 52, 52, 52, 52, 48, 52, 52, 52, 52, 52, 24, 12, 28, 12, 12, + 12, 56, 60, 60, 60, 56, 60, 60, 60, 56, 60, 60, 60, 60, 60, 56, + 60, 60, 60, 60, 60, 56, 60, 60, 60, 60, 60, 24, 12, 28, 12, 0, + /* UTF8 continuation byte range. */ + 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, + 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, + 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, + 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, + /* UTF8 lead byte range. */ + 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, + 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, + 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, + 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, 2, 3, + /* Second last byte. */ + /* */ + /* ASCII range. */ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, + 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, + 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, + 1, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, + 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 1, 1, 1, 1, 0, + /* UTF8 continuation byte range. */ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + /* UTF8 lead byte range. */ + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, + 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, +}; + +/* Context lookup table for small signed integers. */ +static const uint8_t kSigned3BitContextLookup[] = { + 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, + 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, + 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, + 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, + 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, + 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, + 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, + 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, 3, + 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, + 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, + 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, + 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, + 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, + 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, + 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, + 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, +}; + +typedef enum ContextType { + CONTEXT_LSB6 = 0, + CONTEXT_MSB6 = 1, + CONTEXT_UTF8 = 2, + CONTEXT_SIGNED = 3 +} ContextType; + +static BROTLI_INLINE uint8_t Context(uint8_t p1, uint8_t p2, ContextType mode) { + switch (mode) { + case CONTEXT_LSB6: + return p1 & 0x3f; + case CONTEXT_MSB6: + return (uint8_t)(p1 >> 2); + case CONTEXT_UTF8: + return kUTF8ContextLookup[p1] | kUTF8ContextLookup[p2 + 256]; + case CONTEXT_SIGNED: + return (uint8_t)((kSigned3BitContextLookup[p1] << 3) + + kSigned3BitContextLookup[p2]); + default: + return 0; + } +} + +#if defined(__cplusplus) || defined(c_plusplus) +} /* extern "C" */ +#endif + +#endif /* BROTLI_ENC_CONTEXT_H_ */ |