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Diffstat (limited to 'Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/enc/prefix.h')
-rw-r--r-- | Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/enc/prefix.h | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/enc/prefix.h b/Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/enc/prefix.h new file mode 100644 index 00000000000..e279ffe7f88 --- /dev/null +++ b/Build/source/texk/dvisvgm/dvisvgm-src/libs/brotli/enc/prefix.h @@ -0,0 +1,54 @@ +/* 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 for encoding of integers into prefix codes the amount of extra + bits, and the actual values of the extra bits. */ + +#ifndef BROTLI_ENC_PREFIX_H_ +#define BROTLI_ENC_PREFIX_H_ + +#include "../common/constants.h" +#include <brotli/port.h> +#include <brotli/types.h> +#include "./fast_log.h" + +#if defined(__cplusplus) || defined(c_plusplus) +extern "C" { +#endif + +/* Here distance_code is an intermediate code, i.e. one of the special codes or + the actual distance increased by BROTLI_NUM_DISTANCE_SHORT_CODES - 1. */ +static BROTLI_INLINE void PrefixEncodeCopyDistance(size_t distance_code, + size_t num_direct_codes, + size_t postfix_bits, + uint16_t* code, + uint32_t* extra_bits) { + if (distance_code < BROTLI_NUM_DISTANCE_SHORT_CODES + num_direct_codes) { + *code = (uint16_t)distance_code; + *extra_bits = 0; + return; + } else { + size_t dist = ((size_t)1 << (postfix_bits + 2u)) + + (distance_code - BROTLI_NUM_DISTANCE_SHORT_CODES - num_direct_codes); + size_t bucket = Log2FloorNonZero(dist) - 1; + size_t postfix_mask = (1u << postfix_bits) - 1; + size_t postfix = dist & postfix_mask; + size_t prefix = (dist >> bucket) & 1; + size_t offset = (2 + prefix) << bucket; + size_t nbits = bucket - postfix_bits; + *code = (uint16_t)( + (BROTLI_NUM_DISTANCE_SHORT_CODES + num_direct_codes + + ((2 * (nbits - 1) + prefix) << postfix_bits) + postfix)); + *extra_bits = (uint32_t)( + (nbits << 24) | ((dist - offset) >> postfix_bits)); + } +} + +#if defined(__cplusplus) || defined(c_plusplus) +} /* extern "C" */ +#endif + +#endif /* BROTLI_ENC_PREFIX_H_ */ |