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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 02:57:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-19 02:57:58 +0000 |
commit | be1c7e50e1e8809ea56f2c9d472eccd8ffd73a97 (patch) | |
tree | 9754ff1ca740f6346cf8483ec915d4054bc5da2d /web/server/h2o/libh2o/deps/brotli/enc/command.h | |
parent | Initial commit. (diff) | |
download | netdata-be1c7e50e1e8809ea56f2c9d472eccd8ffd73a97.tar.xz netdata-be1c7e50e1e8809ea56f2c9d472eccd8ffd73a97.zip |
Adding upstream version 1.44.3.upstream/1.44.3upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'web/server/h2o/libh2o/deps/brotli/enc/command.h')
-rw-r--r-- | web/server/h2o/libh2o/deps/brotli/enc/command.h | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/web/server/h2o/libh2o/deps/brotli/enc/command.h b/web/server/h2o/libh2o/deps/brotli/enc/command.h new file mode 100644 index 00000000..afb014be --- /dev/null +++ b/web/server/h2o/libh2o/deps/brotli/enc/command.h @@ -0,0 +1,136 @@ +/* Copyright 2013 Google Inc. All Rights Reserved. + + Distributed under MIT license. + See file LICENSE for detail or copy at https://opensource.org/licenses/MIT +*/ + +// This class models a sequence of literals and a backward reference copy. + +#ifndef BROTLI_ENC_COMMAND_H_ +#define BROTLI_ENC_COMMAND_H_ + +#include "./fast_log.h" +#include "./prefix.h" +#include "./types.h" + +namespace brotli { + +static uint32_t kInsBase[] = { 0, 1, 2, 3, 4, 5, 6, 8, 10, 14, 18, 26, 34, 50, + 66, 98, 130, 194, 322, 578, 1090, 2114, 6210, 22594 }; +static uint32_t kInsExtra[] = { 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, + 5, 5, 6, 7, 8, 9, 10, 12, 14, 24 }; +static uint32_t kCopyBase[] = { 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 18, 22, 30, + 38, 54, 70, 102, 134, 198, 326, 582, 1094, 2118 }; +static uint32_t kCopyExtra[] = { 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 2, 2, 3, 3, + 4, 4, 5, 5, 6, 7, 8, 9, 10, 24 }; + +static inline uint16_t GetInsertLengthCode(size_t insertlen) { + if (insertlen < 6) { + return static_cast<uint16_t>(insertlen); + } else if (insertlen < 130) { + insertlen -= 2; + uint32_t nbits = Log2FloorNonZero(insertlen) - 1u; + return static_cast<uint16_t>((nbits << 1) + (insertlen >> nbits) + 2); + } else if (insertlen < 2114) { + return static_cast<uint16_t>(Log2FloorNonZero(insertlen - 66) + 10); + } else if (insertlen < 6210) { + return 21u; + } else if (insertlen < 22594) { + return 22u; + } else { + return 23u; + } +} + +static inline uint16_t GetCopyLengthCode(size_t copylen) { + if (copylen < 10) { + return static_cast<uint16_t>(copylen - 2); + } else if (copylen < 134) { + copylen -= 6; + uint32_t nbits = Log2FloorNonZero(copylen) - 1u; + return static_cast<uint16_t>((nbits << 1) + (copylen >> nbits) + 4); + } else if (copylen < 2118) { + return static_cast<uint16_t>(Log2FloorNonZero(copylen - 70) + 12); + } else { + return 23u; + } +} + +static inline uint16_t CombineLengthCodes( + uint16_t inscode, uint16_t copycode, bool use_last_distance) { + uint16_t bits64 = + static_cast<uint16_t>((copycode & 0x7u) | ((inscode & 0x7u) << 3)); + if (use_last_distance && inscode < 8 && copycode < 16) { + return (copycode < 8) ? bits64 : (bits64 | 64); + } else { + // "To convert an insert-and-copy length code to an insert length code and + // a copy length code, the following table can be used" + static const uint16_t cells[9] = { 128u, 192u, 384u, 256u, 320u, 512u, + 448u, 576u, 640u }; + return cells[(copycode >> 3) + 3 * (inscode >> 3)] | bits64; + } +} + +static inline void GetLengthCode(size_t insertlen, size_t copylen, + bool use_last_distance, + uint16_t* code, uint64_t* extra) { + uint16_t inscode = GetInsertLengthCode(insertlen); + uint16_t copycode = GetCopyLengthCode(copylen); + uint64_t insnumextra = kInsExtra[inscode]; + uint64_t numextra = insnumextra + kCopyExtra[copycode]; + uint64_t insextraval = insertlen - kInsBase[inscode]; + uint64_t copyextraval = copylen - kCopyBase[copycode]; + *code = CombineLengthCodes(inscode, copycode, use_last_distance); + *extra = (numextra << 48) | (copyextraval << insnumextra) | insextraval; +} + +struct Command { + // distance_code is e.g. 0 for same-as-last short code, or 16 for offset 1. + Command(size_t insertlen, size_t copylen, size_t copylen_code, + size_t distance_code) + : insert_len_(static_cast<uint32_t>(insertlen)) + , copy_len_(static_cast<uint32_t>(copylen)) { + // The distance prefix and extra bits are stored in this Command as if + // npostfix and ndirect were 0, they are only recomputed later after the + // clustering if needed. + PrefixEncodeCopyDistance(distance_code, 0, 0, &dist_prefix_, &dist_extra_); + GetLengthCode(insertlen, copylen_code, dist_prefix_ == 0, + &cmd_prefix_, &cmd_extra_); + } + + explicit Command(size_t insertlen) + : insert_len_(static_cast<uint32_t>(insertlen)) + , copy_len_(0), dist_extra_(0), dist_prefix_(16) { + GetLengthCode(insertlen, 4, dist_prefix_ == 0, &cmd_prefix_, &cmd_extra_); + } + + uint32_t DistanceCode() const { + if (dist_prefix_ < 16) { + return dist_prefix_; + } + uint32_t nbits = dist_extra_ >> 24; + uint32_t extra = dist_extra_ & 0xffffff; + uint32_t prefix = dist_prefix_ - 12 - 2 * nbits; + return (prefix << nbits) + extra + 12; + } + + uint32_t DistanceContext() const { + uint32_t r = cmd_prefix_ >> 6; + uint32_t c = cmd_prefix_ & 7; + if ((r == 0 || r == 2 || r == 4 || r == 7) && (c <= 2)) { + return c; + } + return 3; + } + + uint32_t insert_len_; + uint32_t copy_len_; + uint64_t cmd_extra_; + uint32_t dist_extra_; + uint16_t cmd_prefix_; + uint16_t dist_prefix_; +}; + +} // namespace brotli + +#endif // BROTLI_ENC_COMMAND_H_ |