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| -rw-r--r-- | web/server/h2o/libh2o/deps/brotli/enc/encode.h | 211 |
1 files changed, 211 insertions, 0 deletions
diff --git a/web/server/h2o/libh2o/deps/brotli/enc/encode.h b/web/server/h2o/libh2o/deps/brotli/enc/encode.h new file mode 100644 index 00000000..167235c9 --- /dev/null +++ b/web/server/h2o/libh2o/deps/brotli/enc/encode.h @@ -0,0 +1,211 @@ +/* Copyright 2013 Google Inc. All Rights Reserved. + + Distributed under MIT license. + See file LICENSE for detail or copy at https://opensource.org/licenses/MIT +*/ + +// API for Brotli compression + +#ifndef BROTLI_ENC_ENCODE_H_ +#define BROTLI_ENC_ENCODE_H_ + +#include <string> +#include <vector> +#include "./command.h" +#include "./hash.h" +#include "./ringbuffer.h" +#include "./static_dict.h" +#include "./streams.h" +#include "./types.h" + +namespace brotli { + +static const int kMaxWindowBits = 24; +static const int kMinWindowBits = 10; +static const int kMinInputBlockBits = 16; +static const int kMaxInputBlockBits = 24; + +struct BrotliParams { + BrotliParams() + : mode(MODE_GENERIC), + quality(11), + lgwin(22), + lgblock(0), + enable_dictionary(true), + enable_transforms(false), + greedy_block_split(false), + enable_context_modeling(true) {} + + enum Mode { + // Default compression mode. The compressor does not know anything in + // advance about the properties of the input. + MODE_GENERIC = 0, + // Compression mode for UTF-8 format text input. + MODE_TEXT = 1, + // Compression mode used in WOFF 2.0. + MODE_FONT = 2 + }; + Mode mode; + + // Controls the compression-speed vs compression-density tradeoffs. The higher + // the quality, the slower the compression. Range is 0 to 11. + int quality; + // Base 2 logarithm of the sliding window size. Range is 10 to 24. + int lgwin; + // Base 2 logarithm of the maximum input block size. Range is 16 to 24. + // If set to 0, the value will be set based on the quality. + int lgblock; + + // These settings are deprecated and will be ignored. + // All speed vs. size compromises are controlled by the quality param. + bool enable_dictionary; + bool enable_transforms; + bool greedy_block_split; + bool enable_context_modeling; +}; + +// An instance can not be reused for multiple brotli streams. +class BrotliCompressor { + public: + explicit BrotliCompressor(BrotliParams params); + ~BrotliCompressor(); + + // The maximum input size that can be processed at once. + size_t input_block_size() const { return size_t(1) << params_.lgblock; } + + // Encodes the data in input_buffer as a meta-block and writes it to + // encoded_buffer (*encoded_size should be set to the size of + // encoded_buffer) and sets *encoded_size to the number of bytes that + // was written. The input_size must be <= input_block_size(). + // Returns 0 if there was an error and 1 otherwise. + bool WriteMetaBlock(const size_t input_size, + const uint8_t* input_buffer, + const bool is_last, + size_t* encoded_size, + uint8_t* encoded_buffer); + + // Writes a metadata meta-block containing the given input to encoded_buffer. + // *encoded_size should be set to the size of the encoded_buffer. + // Sets *encoded_size to the number of bytes that was written. + // Note that the given input data will not be part of the sliding window and + // thus no backward references can be made to this data from subsequent + // metablocks. + bool WriteMetadata(const size_t input_size, + const uint8_t* input_buffer, + const bool is_last, + size_t* encoded_size, + uint8_t* encoded_buffer); + + // Writes a zero-length meta-block with end-of-input bit set to the + // internal output buffer and copies the output buffer to encoded_buffer + // (*encoded_size should be set to the size of encoded_buffer) and sets + // *encoded_size to the number of bytes written. Returns false if there was + // an error and true otherwise. + bool FinishStream(size_t* encoded_size, uint8_t* encoded_buffer); + + // Copies the given input data to the internal ring buffer of the compressor. + // No processing of the data occurs at this time and this function can be + // called multiple times before calling WriteBrotliData() to process the + // accumulated input. At most input_block_size() bytes of input data can be + // copied to the ring buffer, otherwise the next WriteBrotliData() will fail. + void CopyInputToRingBuffer(const size_t input_size, + const uint8_t* input_buffer); + + // Processes the accumulated input data and sets *out_size to the length of + // the new output meta-block, or to zero if no new output meta-block was + // created (in this case the processed input data is buffered internally). + // If *out_size is positive, *output points to the start of the output data. + // If is_last or force_flush is true, an output meta-block is always created. + // Returns false if the size of the input data is larger than + // input_block_size(). + bool WriteBrotliData(const bool is_last, const bool force_flush, + size_t* out_size, uint8_t** output); + + // Fills the new state with a dictionary for LZ77, warming up the ringbuffer, + // e.g. for custom static dictionaries for data formats. + // Not to be confused with the built-in transformable dictionary of Brotli. + // To decode, use BrotliSetCustomDictionary of the decoder with the same + // dictionary. + void BrotliSetCustomDictionary(size_t size, const uint8_t* dict); + + // No-op, but we keep it here for API backward-compatibility. + void WriteStreamHeader() {} + + private: + uint8_t* GetBrotliStorage(size_t size); + + // Allocates and clears a hash table using memory in "*this", + // stores the number of buckets in "*table_size" and returns a pointer to + // the base of the hash table. + int* GetHashTable(int quality, + size_t input_size, size_t* table_size); + + void WriteMetaBlockInternal(const bool is_last, + size_t* out_size, + uint8_t** output); + + BrotliParams params_; + Hashers* hashers_; + int hash_type_; + uint64_t input_pos_; + RingBuffer* ringbuffer_; + size_t cmd_alloc_size_; + Command* commands_; + size_t num_commands_; + size_t num_literals_; + size_t last_insert_len_; + uint64_t last_flush_pos_; + uint64_t last_processed_pos_; + int dist_cache_[4]; + int saved_dist_cache_[4]; + uint8_t last_byte_; + uint8_t last_byte_bits_; + uint8_t prev_byte_; + uint8_t prev_byte2_; + size_t storage_size_; + uint8_t* storage_; + // Hash table for quality 0 mode. + int small_table_[1 << 10]; // 2KB + int* large_table_; // Allocated only when needed + // Command and distance prefix codes (each 64 symbols, stored back-to-back) + // used for the next block in quality 0. The command prefix code is over a + // smaller alphabet with the following 64 symbols: + // 0 - 15: insert length code 0, copy length code 0 - 15, same distance + // 16 - 39: insert length code 0, copy length code 0 - 23 + // 40 - 63: insert length code 0 - 23, copy length code 0 + // Note that symbols 16 and 40 represent the same code in the full alphabet, + // but we do not use either of them in quality 0. + uint8_t cmd_depths_[128]; + uint16_t cmd_bits_[128]; + // The compressed form of the command and distance prefix codes for the next + // block in quality 0. + uint8_t cmd_code_[512]; + size_t cmd_code_numbits_; + // Command and literal buffers for quality 1. + uint32_t* command_buf_; + uint8_t* literal_buf_; +}; + +// Compresses the data in input_buffer into encoded_buffer, and sets +// *encoded_size to the compressed length. +// Returns 0 if there was an error and 1 otherwise. +int BrotliCompressBuffer(BrotliParams params, + size_t input_size, + const uint8_t* input_buffer, + size_t* encoded_size, + uint8_t* encoded_buffer); + +// Same as above, but uses the specified input and output classes instead +// of reading from and writing to pre-allocated memory buffers. +int BrotliCompress(BrotliParams params, BrotliIn* in, BrotliOut* out); + +// Before compressing the data, sets a custom LZ77 dictionary with +// BrotliCompressor::BrotliSetCustomDictionary. +int BrotliCompressWithCustomDictionary(size_t dictsize, const uint8_t* dict, + BrotliParams params, + BrotliIn* in, BrotliOut* out); + + +} // namespace brotli + +#endif // BROTLI_ENC_ENCODE_H_ |