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Diffstat (limited to 'modules/brotli/enc/encode.c')
| -rw-r--r-- | modules/brotli/enc/encode.c | 1862 |
1 files changed, 1862 insertions, 0 deletions
diff --git a/modules/brotli/enc/encode.c b/modules/brotli/enc/encode.c new file mode 100644 index 000000000..141e70aa2 --- /dev/null +++ b/modules/brotli/enc/encode.c @@ -0,0 +1,1862 @@ +/* Copyright 2013 Google Inc. All Rights Reserved. + + Distributed under MIT license. + See file LICENSE for detail or copy at https://opensource.org/licenses/MIT +*/ + +/* Implementation of Brotli compressor. */ + +#include <brotli/encode.h> + +#include <stdlib.h> /* free, malloc */ +#include <string.h> /* memcpy, memset */ + +#include "../common/constants.h" +#include "../common/context.h" +#include "../common/platform.h" +#include "../common/version.h" +#include "./backward_references.h" +#include "./backward_references_hq.h" +#include "./bit_cost.h" +#include "./brotli_bit_stream.h" +#include "./compress_fragment.h" +#include "./compress_fragment_two_pass.h" +#include "./encoder_dict.h" +#include "./entropy_encode.h" +#include "./fast_log.h" +#include "./hash.h" +#include "./histogram.h" +#include "./memory.h" +#include "./metablock.h" +#include "./prefix.h" +#include "./quality.h" +#include "./ringbuffer.h" +#include "./utf8_util.h" +#include "./write_bits.h" + +#if defined(__cplusplus) || defined(c_plusplus) +extern "C" { +#endif + +#define COPY_ARRAY(dst, src) memcpy(dst, src, sizeof(src)); + +typedef enum BrotliEncoderStreamState { + /* Default state. */ + BROTLI_STREAM_PROCESSING = 0, + /* Intermediate state; after next block is emitted, byte-padding should be + performed before getting back to default state. */ + BROTLI_STREAM_FLUSH_REQUESTED = 1, + /* Last metablock was produced; no more input is acceptable. */ + BROTLI_STREAM_FINISHED = 2, + /* Flushing compressed block and writing meta-data block header. */ + BROTLI_STREAM_METADATA_HEAD = 3, + /* Writing metadata block body. */ + BROTLI_STREAM_METADATA_BODY = 4 +} BrotliEncoderStreamState; + +typedef struct BrotliEncoderStateStruct { + BrotliEncoderParams params; + + MemoryManager memory_manager_; + + HasherHandle hasher_; + 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_[BROTLI_NUM_DISTANCE_SHORT_CODES]; + int saved_dist_cache_[4]; + uint16_t last_bytes_; + uint8_t last_bytes_bits_; + uint8_t prev_byte_; + uint8_t prev_byte2_; + size_t storage_size_; + uint8_t* storage_; + /* Hash table for FAST_ONE_PASS_COMPRESSION_QUALITY mode. */ + int small_table_[1 << 10]; /* 4KiB */ + int* large_table_; /* Allocated only when needed */ + size_t large_table_size_; + /* Command and distance prefix codes (each 64 symbols, stored back-to-back) + used for the next block in FAST_ONE_PASS_COMPRESSION_QUALITY. 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 FAST_ONE_PASS_COMPRESSION_QUALITY. */ + 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 FAST_ONE_PASS_COMPRESSION_QUALITY. */ + uint8_t cmd_code_[512]; + size_t cmd_code_numbits_; + /* Command and literal buffers for FAST_TWO_PASS_COMPRESSION_QUALITY. */ + uint32_t* command_buf_; + uint8_t* literal_buf_; + + uint8_t* next_out_; + size_t available_out_; + size_t total_out_; + /* Temporary buffer for padding flush bits or metadata block header / body. */ + union { + uint64_t u64[2]; + uint8_t u8[16]; + } tiny_buf_; + uint32_t remaining_metadata_bytes_; + BrotliEncoderStreamState stream_state_; + + BROTLI_BOOL is_last_block_emitted_; + BROTLI_BOOL is_initialized_; +} BrotliEncoderStateStruct; + +static BROTLI_BOOL EnsureInitialized(BrotliEncoderState* s); + +static size_t InputBlockSize(BrotliEncoderState* s) { + return (size_t)1 << s->params.lgblock; +} + +static uint64_t UnprocessedInputSize(BrotliEncoderState* s) { + return s->input_pos_ - s->last_processed_pos_; +} + +static size_t RemainingInputBlockSize(BrotliEncoderState* s) { + const uint64_t delta = UnprocessedInputSize(s); + size_t block_size = InputBlockSize(s); + if (delta >= block_size) return 0; + return block_size - (size_t)delta; +} + +BROTLI_BOOL BrotliEncoderSetParameter( + BrotliEncoderState* state, BrotliEncoderParameter p, uint32_t value) { + /* Changing parameters on the fly is not implemented yet. */ + if (state->is_initialized_) return BROTLI_FALSE; + /* TODO: Validate/clamp parameters here. */ + switch (p) { + case BROTLI_PARAM_MODE: + state->params.mode = (BrotliEncoderMode)value; + return BROTLI_TRUE; + + case BROTLI_PARAM_QUALITY: + state->params.quality = (int)value; + return BROTLI_TRUE; + + case BROTLI_PARAM_LGWIN: + state->params.lgwin = (int)value; + return BROTLI_TRUE; + + case BROTLI_PARAM_LGBLOCK: + state->params.lgblock = (int)value; + return BROTLI_TRUE; + + case BROTLI_PARAM_DISABLE_LITERAL_CONTEXT_MODELING: + if ((value != 0) && (value != 1)) return BROTLI_FALSE; + state->params.disable_literal_context_modeling = TO_BROTLI_BOOL(!!value); + return BROTLI_TRUE; + + case BROTLI_PARAM_SIZE_HINT: + state->params.size_hint = value; + return BROTLI_TRUE; + + case BROTLI_PARAM_LARGE_WINDOW: + state->params.large_window = TO_BROTLI_BOOL(!!value); + return BROTLI_TRUE; + + case BROTLI_PARAM_NPOSTFIX: + state->params.dist.distance_postfix_bits = value; + return BROTLI_TRUE; + + case BROTLI_PARAM_NDIRECT: + state->params.dist.num_direct_distance_codes = value; + return BROTLI_TRUE; + + default: return BROTLI_FALSE; + } +} + +/* Wraps 64-bit input position to 32-bit ring-buffer position preserving + "not-a-first-lap" feature. */ +static uint32_t WrapPosition(uint64_t position) { + uint32_t result = (uint32_t)position; + uint64_t gb = position >> 30; + if (gb > 2) { + /* Wrap every 2GiB; The first 3GB are continuous. */ + result = (result & ((1u << 30) - 1)) | ((uint32_t)((gb - 1) & 1) + 1) << 30; + } + return result; +} + +static uint8_t* GetBrotliStorage(BrotliEncoderState* s, size_t size) { + MemoryManager* m = &s->memory_manager_; + if (s->storage_size_ < size) { + BROTLI_FREE(m, s->storage_); + s->storage_ = BROTLI_ALLOC(m, uint8_t, size); + if (BROTLI_IS_OOM(m)) return NULL; + s->storage_size_ = size; + } + return s->storage_; +} + +static size_t HashTableSize(size_t max_table_size, size_t input_size) { + size_t htsize = 256; + while (htsize < max_table_size && htsize < input_size) { + htsize <<= 1; + } + return htsize; +} + +static int* GetHashTable(BrotliEncoderState* s, int quality, + size_t input_size, size_t* table_size) { + /* Use smaller hash table when input.size() is smaller, since we + fill the table, incurring O(hash table size) overhead for + compression, and if the input is short, we won't need that + many hash table entries anyway. */ + MemoryManager* m = &s->memory_manager_; + const size_t max_table_size = MaxHashTableSize(quality); + size_t htsize = HashTableSize(max_table_size, input_size); + int* table; + BROTLI_DCHECK(max_table_size >= 256); + if (quality == FAST_ONE_PASS_COMPRESSION_QUALITY) { + /* Only odd shifts are supported by fast-one-pass. */ + if ((htsize & 0xAAAAA) == 0) { + htsize <<= 1; + } + } + + if (htsize <= sizeof(s->small_table_) / sizeof(s->small_table_[0])) { + table = s->small_table_; + } else { + if (htsize > s->large_table_size_) { + s->large_table_size_ = htsize; + BROTLI_FREE(m, s->large_table_); + s->large_table_ = BROTLI_ALLOC(m, int, htsize); + if (BROTLI_IS_OOM(m)) return 0; + } + table = s->large_table_; + } + + *table_size = htsize; + memset(table, 0, htsize * sizeof(*table)); + return table; +} + +static void EncodeWindowBits(int lgwin, BROTLI_BOOL large_window, + uint16_t* last_bytes, uint8_t* last_bytes_bits) { + if (large_window) { + *last_bytes = (uint16_t)(((lgwin & 0x3F) << 8) | 0x11); + *last_bytes_bits = 14; + } else { + if (lgwin == 16) { + *last_bytes = 0; + *last_bytes_bits = 1; + } else if (lgwin == 17) { + *last_bytes = 1; + *last_bytes_bits = 7; + } else if (lgwin > 17) { + *last_bytes = (uint16_t)(((lgwin - 17) << 1) | 0x01); + *last_bytes_bits = 4; + } else { + *last_bytes = (uint16_t)(((lgwin - 8) << 4) | 0x01); + *last_bytes_bits = 7; + } + } +} + +/* Initializes the command and distance prefix codes for the first block. */ +static void InitCommandPrefixCodes(uint8_t cmd_depths[128], + uint16_t cmd_bits[128], + uint8_t cmd_code[512], + size_t* cmd_code_numbits) { + static const uint8_t kDefaultCommandDepths[128] = { + 0, 4, 4, 5, 6, 6, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, + 0, 0, 0, 4, 4, 4, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, + 7, 7, 10, 10, 10, 10, 10, 10, 0, 4, 4, 5, 5, 5, 6, 6, + 7, 8, 8, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, + 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 6, 6, 6, 6, 6, 6, 5, 5, 5, 5, 5, 5, 4, 4, 4, 4, + 4, 4, 4, 5, 5, 5, 5, 5, 5, 6, 6, 7, 7, 7, 8, 10, + 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, + }; + static const uint16_t kDefaultCommandBits[128] = { + 0, 0, 8, 9, 3, 35, 7, 71, + 39, 103, 23, 47, 175, 111, 239, 31, + 0, 0, 0, 4, 12, 2, 10, 6, + 13, 29, 11, 43, 27, 59, 87, 55, + 15, 79, 319, 831, 191, 703, 447, 959, + 0, 14, 1, 25, 5, 21, 19, 51, + 119, 159, 95, 223, 479, 991, 63, 575, + 127, 639, 383, 895, 255, 767, 511, 1023, + 14, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, + 27, 59, 7, 39, 23, 55, 30, 1, 17, 9, 25, 5, 0, 8, 4, 12, + 2, 10, 6, 21, 13, 29, 3, 19, 11, 15, 47, 31, 95, 63, 127, 255, + 767, 2815, 1791, 3839, 511, 2559, 1535, 3583, 1023, 3071, 2047, 4095, + }; + static const uint8_t kDefaultCommandCode[] = { + 0xff, 0x77, 0xd5, 0xbf, 0xe7, 0xde, 0xea, 0x9e, 0x51, 0x5d, 0xde, 0xc6, + 0x70, 0x57, 0xbc, 0x58, 0x58, 0x58, 0xd8, 0xd8, 0x58, 0xd5, 0xcb, 0x8c, + 0xea, 0xe0, 0xc3, 0x87, 0x1f, 0x83, 0xc1, 0x60, 0x1c, 0x67, 0xb2, 0xaa, + 0x06, 0x83, 0xc1, 0x60, 0x30, 0x18, 0xcc, 0xa1, 0xce, 0x88, 0x54, 0x94, + 0x46, 0xe1, 0xb0, 0xd0, 0x4e, 0xb2, 0xf7, 0x04, 0x00, + }; + static const size_t kDefaultCommandCodeNumBits = 448; + COPY_ARRAY(cmd_depths, kDefaultCommandDepths); + COPY_ARRAY(cmd_bits, kDefaultCommandBits); + + /* Initialize the pre-compressed form of the command and distance prefix + codes. */ + COPY_ARRAY(cmd_code, kDefaultCommandCode); + *cmd_code_numbits = kDefaultCommandCodeNumBits; +} + +/* Decide about the context map based on the ability of the prediction + ability of the previous byte UTF8-prefix on the next byte. The + prediction ability is calculated as Shannon entropy. Here we need + Shannon entropy instead of 'BitsEntropy' since the prefix will be + encoded with the remaining 6 bits of the following byte, and + BitsEntropy will assume that symbol to be stored alone using Huffman + coding. */ +static void ChooseContextMap(int quality, + uint32_t* bigram_histo, + size_t* num_literal_contexts, + const uint32_t** literal_context_map) { + static const uint32_t kStaticContextMapContinuation[64] = { + 1, 1, 2, 2, 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, + }; + static const uint32_t kStaticContextMapSimpleUTF8[64] = { + 0, 0, 1, 1, 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, + }; + + uint32_t monogram_histo[3] = { 0 }; + uint32_t two_prefix_histo[6] = { 0 }; + size_t total; + size_t i; + size_t dummy; + double entropy[4]; + for (i = 0; i < 9; ++i) { + monogram_histo[i % 3] += bigram_histo[i]; + two_prefix_histo[i % 6] += bigram_histo[i]; + } + entropy[1] = ShannonEntropy(monogram_histo, 3, &dummy); + entropy[2] = (ShannonEntropy(two_prefix_histo, 3, &dummy) + + ShannonEntropy(two_prefix_histo + 3, 3, &dummy)); + entropy[3] = 0; + for (i = 0; i < 3; ++i) { + entropy[3] += ShannonEntropy(bigram_histo + 3 * i, 3, &dummy); + } + + total = monogram_histo[0] + monogram_histo[1] + monogram_histo[2]; + BROTLI_DCHECK(total != 0); + entropy[0] = 1.0 / (double)total; + entropy[1] *= entropy[0]; + entropy[2] *= entropy[0]; + entropy[3] *= entropy[0]; + + if (quality < MIN_QUALITY_FOR_HQ_CONTEXT_MODELING) { + /* 3 context models is a bit slower, don't use it at lower qualities. */ + entropy[3] = entropy[1] * 10; + } + /* If expected savings by symbol are less than 0.2 bits, skip the + context modeling -- in exchange for faster decoding speed. */ + if (entropy[1] - entropy[2] < 0.2 && + entropy[1] - entropy[3] < 0.2) { + *num_literal_contexts = 1; + } else if (entropy[2] - entropy[3] < 0.02) { + *num_literal_contexts = 2; + *literal_context_map = kStaticContextMapSimpleUTF8; + } else { + *num_literal_contexts = 3; + *literal_context_map = kStaticContextMapContinuation; + } +} + +/* Decide if we want to use a more complex static context map containing 13 + context values, based on the entropy reduction of histograms over the + first 5 bits of literals. */ +static BROTLI_BOOL ShouldUseComplexStaticContextMap(const uint8_t* input, + size_t start_pos, size_t length, size_t mask, int quality, size_t size_hint, + size_t* num_literal_contexts, const uint32_t** literal_context_map) { + static const uint32_t kStaticContextMapComplexUTF8[64] = { + 11, 11, 12, 12, /* 0 special */ + 0, 0, 0, 0, /* 4 lf */ + 1, 1, 9, 9, /* 8 space */ + 2, 2, 2, 2, /* !, first after space/lf and after something else. */ + 1, 1, 1, 1, /* " */ + 8, 3, 3, 3, /* % */ + 1, 1, 1, 1, /* ({[ */ + 2, 2, 2, 2, /* }]) */ + 8, 4, 4, 4, /* :; */ + 8, 7, 4, 4, /* . */ + 8, 0, 0, 0, /* > */ + 3, 3, 3, 3, /* [0..9] */ + 5, 5, 10, 5, /* [A-Z] */ + 5, 5, 10, 5, + 6, 6, 6, 6, /* [a-z] */ + 6, 6, 6, 6, + }; + BROTLI_UNUSED(quality); + /* Try the more complex static context map only for long data. */ + if (size_hint < (1 << 20)) { + return BROTLI_FALSE; + } else { + const size_t end_pos = start_pos + length; + /* To make entropy calculations faster and to fit on the stack, we collect + histograms over the 5 most significant bits of literals. One histogram + without context and 13 additional histograms for each context value. */ + uint32_t combined_histo[32] = { 0 }; + uint32_t context_histo[13][32] = { { 0 } }; + uint32_t total = 0; + double entropy[3]; + size_t dummy; + size_t i; + ContextLut utf8_lut = BROTLI_CONTEXT_LUT(CONTEXT_UTF8); + for (; start_pos + 64 <= end_pos; start_pos += 4096) { + const size_t stride_end_pos = start_pos + 64; + uint8_t prev2 = input[start_pos & mask]; + uint8_t prev1 = input[(start_pos + 1) & mask]; + size_t pos; + /* To make the analysis of the data faster we only examine 64 byte long + strides at every 4kB intervals. */ + for (pos = start_pos + 2; pos < stride_end_pos; ++pos) { + const uint8_t literal = input[pos & mask]; + const uint8_t context = (uint8_t)kStaticContextMapComplexUTF8[ + BROTLI_CONTEXT(prev1, prev2, utf8_lut)]; + ++total; + ++combined_histo[literal >> 3]; + ++context_histo[context][literal >> 3]; + prev2 = prev1; + prev1 = literal; + } + } + entropy[1] = ShannonEntropy(combined_histo, 32, &dummy); + entropy[2] = 0; + for (i = 0; i < 13; ++i) { + entropy[2] += ShannonEntropy(&context_histo[i][0], 32, &dummy); + } + entropy[0] = 1.0 / (double)total; + entropy[1] *= entropy[0]; + entropy[2] *= entropy[0]; + /* The triggering heuristics below were tuned by compressing the individual + files of the silesia corpus. If we skip this kind of context modeling + for not very well compressible input (i.e. entropy using context modeling + is 60% of maximal entropy) or if expected savings by symbol are less + than 0.2 bits, then in every case when it triggers, the final compression + ratio is improved. Note however that this heuristics might be too strict + for some cases and could be tuned further. */ + if (entropy[2] > 3.0 || entropy[1] - entropy[2] < 0.2) { + return BROTLI_FALSE; + } else { + *num_literal_contexts = 13; + *literal_context_map = kStaticContextMapComplexUTF8; + return BROTLI_TRUE; + } + } +} + +static void DecideOverLiteralContextModeling(const uint8_t* input, + size_t start_pos, size_t length, size_t mask, int quality, size_t size_hint, + size_t* num_literal_contexts, const uint32_t** literal_context_map) { + if (quality < MIN_QUALITY_FOR_CONTEXT_MODELING || length < 64) { + return; + } else if (ShouldUseComplexStaticContextMap( + input, start_pos, length, mask, quality, size_hint, + num_literal_contexts, literal_context_map)) { + /* Context map was already set, nothing else to do. */ + } else { + /* Gather bi-gram data of the UTF8 byte prefixes. To make the analysis of + UTF8 data faster we only examine 64 byte long strides at every 4kB + intervals. */ + const size_t end_pos = start_pos + length; + uint32_t bigram_prefix_histo[9] = { 0 }; + for (; start_pos + 64 <= end_pos; start_pos += 4096) { + static const int lut[4] = { 0, 0, 1, 2 }; + const size_t stride_end_pos = start_pos + 64; + int prev = lut[input[start_pos & mask] >> 6] * 3; + size_t pos; + for (pos = start_pos + 1; pos < stride_end_pos; ++pos) { + const uint8_t literal = input[pos & mask]; + ++bigram_prefix_histo[prev + lut[literal >> 6]]; + prev = lut[literal >> 6] * 3; + } + } + ChooseContextMap(quality, &bigram_prefix_histo[0], num_literal_contexts, + literal_context_map); + } +} + +static BROTLI_BOOL ShouldCompress( + const uint8_t* data, const size_t mask, const uint64_t last_flush_pos, + const size_t bytes, const size_t num_literals, const size_t num_commands) { + /* TODO: find more precise minimal block overhead. */ + if (bytes <= 2) return BROTLI_FALSE; + if (num_commands < (bytes >> 8) + 2) { + if (num_literals > 0.99 * (double)bytes) { + uint32_t literal_histo[256] = { 0 }; + static const uint32_t kSampleRate = 13; + static const double kMinEntropy = 7.92; + const double bit_cost_threshold = + (double)bytes * kMinEntropy / kSampleRate; + size_t t = (bytes + kSampleRate - 1) / kSampleRate; + uint32_t pos = (uint32_t)last_flush_pos; + size_t i; + for (i = 0; i < t; i++) { + ++literal_histo[data[pos & mask]]; + pos += kSampleRate; + } + if (BitsEntropy(literal_histo, 256) > bit_cost_threshold) { + return BROTLI_FALSE; + } + } + } + return BROTLI_TRUE; +} + +/* Chooses the literal context mode for a metablock */ +static ContextType ChooseContextMode(const BrotliEncoderParams* params, + const uint8_t* data, const size_t pos, const size_t mask, + const size_t length) { + /* We only do the computation for the option of something else than + CONTEXT_UTF8 for the highest qualities */ + if (params->quality >= MIN_QUALITY_FOR_HQ_BLOCK_SPLITTING && + !BrotliIsMostlyUTF8(data, pos, mask, length, kMinUTF8Ratio)) { + return CONTEXT_SIGNED; + } + return CONTEXT_UTF8; +} + +static void WriteMetaBlockInternal(MemoryManager* m, + const uint8_t* data, + const size_t mask, + const uint64_t last_flush_pos, + const size_t bytes, + const BROTLI_BOOL is_last, + ContextType literal_context_mode, + const BrotliEncoderParams* params, + const uint8_t prev_byte, + const uint8_t prev_byte2, + const size_t num_literals, + const size_t num_commands, + Command* commands, + const int* saved_dist_cache, + int* dist_cache, + size_t* storage_ix, + uint8_t* storage) { + const uint32_t wrapped_last_flush_pos = WrapPosition(last_flush_pos); + uint16_t last_bytes; + uint8_t last_bytes_bits; + ContextLut literal_context_lut = BROTLI_CONTEXT_LUT(literal_context_mode); + BrotliEncoderParams block_params = *params; + + if (bytes == 0) { + /* Write the ISLAST and ISEMPTY bits. */ + BrotliWriteBits(2, 3, storage_ix, storage); + *storage_ix = (*storage_ix + 7u) & ~7u; + return; + } + + if (!ShouldCompress(data, mask, last_flush_pos, bytes, + num_literals, num_commands)) { + /* Restore the distance cache, as its last update by + CreateBackwardReferences is now unused. */ + memcpy(dist_cache, saved_dist_cache, 4 * sizeof(dist_cache[0])); + BrotliStoreUncompressedMetaBlock(is_last, data, + wrapped_last_flush_pos, mask, bytes, + storage_ix, storage); + return; + } + + BROTLI_DCHECK(*storage_ix <= 14); + last_bytes = (uint16_t)((storage[1] << 8) | storage[0]); + last_bytes_bits = (uint8_t)(*storage_ix); + if (params->quality <= MAX_QUALITY_FOR_STATIC_ENTROPY_CODES) { + BrotliStoreMetaBlockFast(m, data, wrapped_last_flush_pos, + bytes, mask, is_last, params, + commands, num_commands, + storage_ix, storage); + if (BROTLI_IS_OOM(m)) return; + } else if (params->quality < MIN_QUALITY_FOR_BLOCK_SPLIT) { + BrotliStoreMetaBlockTrivial(m, data, wrapped_last_flush_pos, + bytes, mask, is_last, params, + commands, num_commands, + storage_ix, storage); + if (BROTLI_IS_OOM(m)) return; + } else { + MetaBlockSplit mb; + InitMetaBlockSplit(&mb); + if (params->quality < MIN_QUALITY_FOR_HQ_BLOCK_SPLITTING) { + size_t num_literal_contexts = 1; + const uint32_t* literal_context_map = NULL; + if (!params->disable_literal_context_modeling) { + DecideOverLiteralContextModeling( + data, wrapped_last_flush_pos, bytes, mask, params->quality, + params->size_hint, &num_literal_contexts, + &literal_context_map); + } + BrotliBuildMetaBlockGreedy(m, data, wrapped_last_flush_pos, mask, + prev_byte, prev_byte2, literal_context_lut, num_literal_contexts, + literal_context_map, commands, num_commands, &mb); + if (BROTLI_IS_OOM(m)) return; + } else { + BrotliBuildMetaBlock(m, data, wrapped_last_flush_pos, mask, &block_params, + prev_byte, prev_byte2, + commands, num_commands, + literal_context_mode, + &mb); + if (BROTLI_IS_OOM(m)) return; + } + if (params->quality >= MIN_QUALITY_FOR_OPTIMIZE_HISTOGRAMS) { + /* The number of distance symbols effectively used for distance + histograms. It might be less than distance alphabet size + for "Large Window Brotli" (32-bit). */ + uint32_t num_effective_dist_codes = block_params.dist.alphabet_size; + if (num_effective_dist_codes > BROTLI_NUM_HISTOGRAM_DISTANCE_SYMBOLS) { + num_effective_dist_codes = BROTLI_NUM_HISTOGRAM_DISTANCE_SYMBOLS; + } + BrotliOptimizeHistograms(num_effective_dist_codes, &mb); + } + BrotliStoreMetaBlock(m, data, wrapped_last_flush_pos, bytes, mask, + prev_byte, prev_byte2, + is_last, + &block_params, + literal_context_mode, + commands, num_commands, + &mb, + storage_ix, storage); + if (BROTLI_IS_OOM(m)) return; + DestroyMetaBlockSplit(m, &mb); + } + if (bytes + 4 < (*storage_ix >> 3)) { + /* Restore the distance cache and last byte. */ + memcpy(dist_cache, saved_dist_cache, 4 * sizeof(dist_cache[0])); + storage[0] = (uint8_t)last_bytes; + storage[1] = (uint8_t)(last_bytes >> 8); + *storage_ix = last_bytes_bits; + BrotliStoreUncompressedMetaBlock(is_last, data, + wrapped_last_flush_pos, mask, + bytes, storage_ix, storage); + } +} + +static void ChooseDistanceParams(BrotliEncoderParams* params) { + uint32_t distance_postfix_bits = 0; + uint32_t num_direct_distance_codes = 0; + + if (params->quality >= MIN_QUALITY_FOR_NONZERO_DISTANCE_PARAMS) { + uint32_t ndirect_msb; + if (params->mode == BROTLI_MODE_FONT) { + distance_postfix_bits = 1; + num_direct_distance_codes = 12; + } else { + distance_postfix_bits = params->dist.distance_postfix_bits; + num_direct_distance_codes = params->dist.num_direct_distance_codes; + } + ndirect_msb = (num_direct_distance_codes >> distance_postfix_bits) & 0x0F; + if (distance_postfix_bits > BROTLI_MAX_NPOSTFIX || + num_direct_distance_codes > BROTLI_MAX_NDIRECT || + (ndirect_msb << distance_postfix_bits) != num_direct_distance_codes) { + distance_postfix_bits = 0; + num_direct_distance_codes = 0; + } + } + + BrotliInitDistanceParams( + params, distance_postfix_bits, num_direct_distance_codes); +} + +static BROTLI_BOOL EnsureInitialized(BrotliEncoderState* s) { + if (BROTLI_IS_OOM(&s->memory_manager_)) return BROTLI_FALSE; + if (s->is_initialized_) return BROTLI_TRUE; + + s->last_bytes_bits_ = 0; + s->last_bytes_ = 0; + s->remaining_metadata_bytes_ = BROTLI_UINT32_MAX; + + SanitizeParams(&s->params); + s->params.lgblock = ComputeLgBlock(&s->params); + ChooseDistanceParams(&s->params); + + RingBufferSetup(&s->params, &s->ringbuffer_); + + /* Initialize last byte with stream header. */ + { + int lgwin = s->params.lgwin; + if (s->params.quality == FAST_ONE_PASS_COMPRESSION_QUALITY || + s->params.quality == FAST_TWO_PASS_COMPRESSION_QUALITY) { + lgwin = BROTLI_MAX(int, lgwin, 18); + } + EncodeWindowBits(lgwin, s->params.large_window, + &s->last_bytes_, &s->last_bytes_bits_); + } + + if (s->params.quality == FAST_ONE_PASS_COMPRESSION_QUALITY) { + InitCommandPrefixCodes(s->cmd_depths_, s->cmd_bits_, + s->cmd_code_, &s->cmd_code_numbits_); + } + + s->is_initialized_ = BROTLI_TRUE; + return BROTLI_TRUE; +} + +static void BrotliEncoderInitParams(BrotliEncoderParams* params) { + params->mode = BROTLI_DEFAULT_MODE; + params->large_window = BROTLI_FALSE; + params->quality = BROTLI_DEFAULT_QUALITY; + params->lgwin = BROTLI_DEFAULT_WINDOW; + params->lgblock = 0; + params->size_hint = 0; + params->disable_literal_context_modeling = BROTLI_FALSE; + BrotliInitEncoderDictionary(¶ms->dictionary); + params->dist.distance_postfix_bits = 0; + params->dist.num_direct_distance_codes = 0; + params->dist.alphabet_size = + BROTLI_DISTANCE_ALPHABET_SIZE(0, 0, BROTLI_MAX_DISTANCE_BITS); + params->dist.max_distance = BROTLI_MAX_DISTANCE; +} + +static void BrotliEncoderInitState(BrotliEncoderState* s) { + BrotliEncoderInitParams(&s->params); + s->input_pos_ = 0; + s->num_commands_ = 0; + s->num_literals_ = 0; + s->last_insert_len_ = 0; + s->last_flush_pos_ = 0; + s->last_processed_pos_ = 0; + s->prev_byte_ = 0; + s->prev_byte2_ = 0; + s->storage_size_ = 0; + s->storage_ = 0; + s->hasher_ = NULL; + s->large_table_ = NULL; + s->large_table_size_ = 0; + s->cmd_code_numbits_ = 0; + s->command_buf_ = NULL; + s->literal_buf_ = NULL; + s->next_out_ = NULL; + s->available_out_ = 0; + s->total_out_ = 0; + s->stream_state_ = BROTLI_STREAM_PROCESSING; + s->is_last_block_emitted_ = BROTLI_FALSE; + s->is_initialized_ = BROTLI_FALSE; + + RingBufferInit(&s->ringbuffer_); + + s->commands_ = 0; + s->cmd_alloc_size_ = 0; + + /* Initialize distance cache. */ + s->dist_cache_[0] = 4; + s->dist_cache_[1] = 11; + s->dist_cache_[2] = 15; + s->dist_cache_[3] = 16; + /* Save the state of the distance cache in case we need to restore it for + emitting an uncompressed block. */ + memcpy(s->saved_dist_cache_, s->dist_cache_, sizeof(s->saved_dist_cache_)); +} + +BrotliEncoderState* BrotliEncoderCreateInstance( + brotli_alloc_func alloc_func, brotli_free_func free_func, void* opaque) { + BrotliEncoderState* state = 0; + if (!alloc_func && !free_func) { + state = (BrotliEncoderState*)malloc(sizeof(BrotliEncoderState)); + } else if (alloc_func && free_func) { + state = (BrotliEncoderState*)alloc_func(opaque, sizeof(BrotliEncoderState)); + } + if (state == 0) { + /* BROTLI_DUMP(); */ + return 0; + } + BrotliInitMemoryManager( + &state->memory_manager_, alloc_func, free_func, opaque); + BrotliEncoderInitState(state); + return state; +} + +static void BrotliEncoderCleanupState(BrotliEncoderState* s) { + MemoryManager* m = &s->memory_manager_; + if (BROTLI_IS_OOM(m)) { + BrotliWipeOutMemoryManager(m); + return; + } + BROTLI_FREE(m, s->storage_); + BROTLI_FREE(m, s->commands_); + RingBufferFree(m, &s->ringbuffer_); + DestroyHasher(m, &s->hasher_); + BROTLI_FREE(m, s->large_table_); + BROTLI_FREE(m, s->command_buf_); + BROTLI_FREE(m, s->literal_buf_); +} + +/* Deinitializes and frees BrotliEncoderState instance. */ +void BrotliEncoderDestroyInstance(BrotliEncoderState* state) { + if (!state) { + return; + } else { + MemoryManager* m = &state->memory_manager_; + brotli_free_func free_func = m->free_func; + void* opaque = m->opaque; + BrotliEncoderCleanupState(state); + free_func(opaque, state); + } +} + +/* + 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. + */ +static void CopyInputToRingBuffer(BrotliEncoderState* s, + const size_t input_size, + const uint8_t* input_buffer) { + RingBuffer* ringbuffer_ = &s->ringbuffer_; + MemoryManager* m = &s->memory_manager_; + RingBufferWrite(m, input_buffer, input_size, ringbuffer_); + if (BROTLI_IS_OOM(m)) return; + s->input_pos_ += input_size; + + /* TL;DR: If needed, initialize 7 more bytes in the ring buffer to make the + hashing not depend on uninitialized data. This makes compression + deterministic and it prevents uninitialized memory warnings in Valgrind. + Even without erasing, the output would be valid (but nondeterministic). + + Background information: The compressor stores short (at most 8 bytes) + substrings of the input already read in a hash table, and detects + repetitions by looking up such substrings in the hash table. If it + can find a substring, it checks whether the substring is really there + in the ring buffer (or it's just a hash collision). Should the hash + table become corrupt, this check makes sure that the output is + still valid, albeit the compression ratio would be bad. + + The compressor populates the hash table from the ring buffer as it's + reading new bytes from the input. However, at the last few indexes of + the ring buffer, there are not enough bytes to build full-length + substrings from. Since the hash table always contains full-length + substrings, we erase with dummy zeros here to make sure that those + substrings will contain zeros at the end instead of uninitialized + data. + + Please note that erasing is not necessary (because the + memory region is already initialized since he ring buffer + has a `tail' that holds a copy of the beginning,) so we + skip erasing if we have already gone around at least once in + the ring buffer. + + Only clear during the first round of ring-buffer writes. On + subsequent rounds data in the ring-buffer would be affected. */ + if (ringbuffer_->pos_ <= ringbuffer_->mask_) { + /* This is the first time when the ring buffer is being written. + We clear 7 bytes just after the bytes that have been copied from + the input buffer. + + The ring-buffer has a "tail" that holds a copy of the beginning, + but only once the ring buffer has been fully written once, i.e., + pos <= mask. For the first time, we need to write values + in this tail (where index may be larger than mask), so that + we have exactly defined behavior and don't read uninitialized + memory. Due to performance reasons, hashing reads data using a + LOAD64, which can go 7 bytes beyond the bytes written in the + ring-buffer. */ + memset(ringbuffer_->buffer_ + ringbuffer_->pos_, 0, 7); + } +} + +/* Marks all input as processed. + Returns true if position wrapping occurs. */ +static BROTLI_BOOL UpdateLastProcessedPos(BrotliEncoderState* s) { + uint32_t wrapped_last_processed_pos = WrapPosition(s->last_processed_pos_); + uint32_t wrapped_input_pos = WrapPosition(s->input_pos_); + s->last_processed_pos_ = s->input_pos_; + return TO_BROTLI_BOOL(wrapped_input_pos < wrapped_last_processed_pos); +} + +static void ExtendLastCommand(BrotliEncoderState* s, uint32_t* bytes, + uint32_t* wrapped_last_processed_pos) { + Command* last_command = &s->commands_[s->num_commands_ - 1]; + const uint8_t* data = s->ringbuffer_.buffer_; + const uint32_t mask = s->ringbuffer_.mask_; + uint64_t max_backward_distance = + (((uint64_t)1) << s->params.lgwin) - BROTLI_WINDOW_GAP; + uint64_t last_copy_len = last_command->copy_len_ & 0x1FFFFFF; + uint64_t last_processed_pos = s->last_processed_pos_ - last_copy_len; + uint64_t max_distance = last_processed_pos < max_backward_distance ? + last_processed_pos : max_backward_distance; + uint64_t cmd_dist = (uint64_t)s->dist_cache_[0]; + uint32_t distance_code = CommandRestoreDistanceCode(last_command, + &s->params.dist); + if (distance_code < BROTLI_NUM_DISTANCE_SHORT_CODES || + distance_code - (BROTLI_NUM_DISTANCE_SHORT_CODES - 1) == cmd_dist) { + if (cmd_dist <= max_distance) { + while (*bytes != 0 && data[*wrapped_last_processed_pos & mask] == + data[(*wrapped_last_processed_pos - cmd_dist) & mask]) { + last_command->copy_len_++; + (*bytes)--; + (*wrapped_last_processed_pos)++; + } + } + /* The copy length is at most the metablock size, and thus expressible. */ + GetLengthCode(last_command->insert_len_, + (size_t)((int)(last_command->copy_len_ & 0x1FFFFFF) + + (int)(last_command->copy_len_ >> 25)), + TO_BROTLI_BOOL((last_command->dist_prefix_ & 0x3FF) == 0), + &last_command->cmd_prefix_); + } +} + +/* + 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 has been + 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 BROTLI_TRUE, an output meta-block is + always created. However, until |is_last| is BROTLI_TRUE encoder may retain up + to 7 bits of the last byte of output. To force encoder to dump the remaining + bits use WriteMetadata() to append an empty meta-data block. + Returns BROTLI_FALSE if the size of the input data is larger than + input_block_size(). + */ +static BROTLI_BOOL EncodeData( + BrotliEncoderState* s, const BROTLI_BOOL is_last, + const BROTLI_BOOL force_flush, size_t* out_size, uint8_t** output) { + const uint64_t delta = UnprocessedInputSize(s); + uint32_t bytes = (uint32_t)delta; + uint32_t wrapped_last_processed_pos = WrapPosition(s->last_processed_pos_); + uint8_t* data; + uint32_t mask; + MemoryManager* m = &s->memory_manager_; + ContextType literal_context_mode; + + data = s->ringbuffer_.buffer_; + mask = s->ringbuffer_.mask_; + + /* Adding more blocks after "last" block is forbidden. */ + if (s->is_last_block_emitted_) return BROTLI_FALSE; + if (is_last) s->is_last_block_emitted_ = BROTLI_TRUE; + + if (delta > InputBlockSize(s)) { + return BROTLI_FALSE; + } + if (s->params.quality == FAST_TWO_PASS_COMPRESSION_QUALITY && + !s->command_buf_) { + s->command_buf_ = + BROTLI_ALLOC(m, uint32_t, kCompressFragmentTwoPassBlockSize); + s->literal_buf_ = + BROTLI_ALLOC(m, uint8_t, kCompressFragmentTwoPassBlockSize); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + } + + if (s->params.quality == FAST_ONE_PASS_COMPRESSION_QUALITY || + s->params.quality == FAST_TWO_PASS_COMPRESSION_QUALITY) { + uint8_t* storage; + size_t storage_ix = s->last_bytes_bits_; + size_t table_size; + int* table; + + if (delta == 0 && !is_last) { + /* We have no new input data and we don't have to finish the stream, so + nothing to do. */ + *out_size = 0; + return BROTLI_TRUE; + } + storage = GetBrotliStorage(s, 2 * bytes + 503); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + storage[0] = (uint8_t)s->last_bytes_; + storage[1] = (uint8_t)(s->last_bytes_ >> 8); + table = GetHashTable(s, s->params.quality, bytes, &table_size); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + if (s->params.quality == FAST_ONE_PASS_COMPRESSION_QUALITY) { + BrotliCompressFragmentFast( + m, &data[wrapped_last_processed_pos & mask], + bytes, is_last, + table, table_size, + s->cmd_depths_, s->cmd_bits_, + &s->cmd_code_numbits_, s->cmd_code_, + &storage_ix, storage); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + } else { + BrotliCompressFragmentTwoPass( + m, &data[wrapped_last_processed_pos & mask], + bytes, is_last, + s->command_buf_, s->literal_buf_, + table, table_size, + &storage_ix, storage); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + } + s->last_bytes_ = (uint16_t)(storage[storage_ix >> 3]); + s->last_bytes_bits_ = storage_ix & 7u; + UpdateLastProcessedPos(s); + *output = &storage[0]; + *out_size = storage_ix >> 3; + return BROTLI_TRUE; + } + + { + /* Theoretical max number of commands is 1 per 2 bytes. */ + size_t newsize = s->num_commands_ + bytes / 2 + 1; + if (newsize > s->cmd_alloc_size_) { + Command* new_commands; + /* Reserve a bit more memory to allow merging with a next block + without reallocation: that would impact speed. */ + newsize += (bytes / 4) + 16; + s->cmd_alloc_size_ = newsize; + new_commands = BROTLI_ALLOC(m, Command, newsize); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + if (s->commands_) { + memcpy(new_commands, s->commands_, sizeof(Command) * s->num_commands_); + BROTLI_FREE(m, s->commands_); + } + s->commands_ = new_commands; + } + } + + InitOrStitchToPreviousBlock(m, &s->hasher_, data, mask, &s->params, + wrapped_last_processed_pos, bytes, is_last); + + literal_context_mode = ChooseContextMode( + &s->params, data, WrapPosition(s->last_flush_pos_), + mask, (size_t)(s->input_pos_ - s->last_flush_pos_)); + + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + + if (s->num_commands_ && s->last_insert_len_ == 0) { + ExtendLastCommand(s, &bytes, &wrapped_last_processed_pos); + } + + if (s->params.quality == ZOPFLIFICATION_QUALITY) { + BROTLI_DCHECK(s->params.hasher.type == 10); + BrotliCreateZopfliBackwardReferences(m, bytes, wrapped_last_processed_pos, + data, mask, &s->params, s->hasher_, s->dist_cache_, + &s->last_insert_len_, &s->commands_[s->num_commands_], + &s->num_commands_, &s->num_literals_); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + } else if (s->params.quality == HQ_ZOPFLIFICATION_QUALITY) { + BROTLI_DCHECK(s->params.hasher.type == 10); + BrotliCreateHqZopfliBackwardReferences(m, bytes, wrapped_last_processed_pos, + data, mask, &s->params, s->hasher_, s->dist_cache_, + &s->last_insert_len_, &s->commands_[s->num_commands_], + &s->num_commands_, &s->num_literals_); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + } else { + BrotliCreateBackwardReferences(bytes, wrapped_last_processed_pos, + data, mask, &s->params, s->hasher_, s->dist_cache_, + &s->last_insert_len_, &s->commands_[s->num_commands_], + &s->num_commands_, &s->num_literals_); + } + + { + const size_t max_length = MaxMetablockSize(&s->params); + const size_t max_literals = max_length / 8; + const size_t max_commands = max_length / 8; + const size_t processed_bytes = (size_t)(s->input_pos_ - s->last_flush_pos_); + /* If maximal possible additional block doesn't fit metablock, flush now. */ + /* TODO: Postpone decision until next block arrives? */ + const BROTLI_BOOL next_input_fits_metablock = TO_BROTLI_BOOL( + processed_bytes + InputBlockSize(s) <= max_length); + /* If block splitting is not used, then flush as soon as there is some + amount of commands / literals produced. */ + const BROTLI_BOOL should_flush = TO_BROTLI_BOOL( + s->params.quality < MIN_QUALITY_FOR_BLOCK_SPLIT && + s->num_literals_ + s->num_commands_ >= MAX_NUM_DELAYED_SYMBOLS); + if (!is_last && !force_flush && !should_flush && + next_input_fits_metablock && + s->num_literals_ < max_literals && + s->num_commands_ < max_commands) { + /* Merge with next input block. Everything will happen later. */ + if (UpdateLastProcessedPos(s)) { + HasherReset(s->hasher_); + } + *out_size = 0; + return BROTLI_TRUE; + } + } + + /* Create the last insert-only command. */ + if (s->last_insert_len_ > 0) { + InitInsertCommand(&s->commands_[s->num_commands_++], s->last_insert_len_); + s->num_literals_ += s->last_insert_len_; + s->last_insert_len_ = 0; + } + + if (!is_last && s->input_pos_ == s->last_flush_pos_) { + /* We have no new input data and we don't have to finish the stream, so + nothing to do. */ + *out_size = 0; + return BROTLI_TRUE; + } + BROTLI_DCHECK(s->input_pos_ >= s->last_flush_pos_); + BROTLI_DCHECK(s->input_pos_ > s->last_flush_pos_ || is_last); + BROTLI_DCHECK(s->input_pos_ - s->last_flush_pos_ <= 1u << 24); + { + const uint32_t metablock_size = + (uint32_t)(s->input_pos_ - s->last_flush_pos_); + uint8_t* storage = GetBrotliStorage(s, 2 * metablock_size + 503); + size_t storage_ix = s->last_bytes_bits_; + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + storage[0] = (uint8_t)s->last_bytes_; + storage[1] = (uint8_t)(s->last_bytes_ >> 8); + WriteMetaBlockInternal( + m, data, mask, s->last_flush_pos_, metablock_size, is_last, + literal_context_mode, &s->params, s->prev_byte_, s->prev_byte2_, + s->num_literals_, s->num_commands_, s->commands_, s->saved_dist_cache_, + s->dist_cache_, &storage_ix, storage); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + s->last_bytes_ = (uint16_t)(storage[storage_ix >> 3]); + s->last_bytes_bits_ = storage_ix & 7u; + s->last_flush_pos_ = s->input_pos_; + if (UpdateLastProcessedPos(s)) { + HasherReset(s->hasher_); + } + if (s->last_flush_pos_ > 0) { + s->prev_byte_ = data[((uint32_t)s->last_flush_pos_ - 1) & mask]; + } + if (s->last_flush_pos_ > 1) { + s->prev_byte2_ = data[(uint32_t)(s->last_flush_pos_ - 2) & mask]; + } + s->num_commands_ = 0; + s->num_literals_ = 0; + /* Save the state of the distance cache in case we need to restore it for + emitting an uncompressed block. */ + memcpy(s->saved_dist_cache_, s->dist_cache_, sizeof(s->saved_dist_cache_)); + *output = &storage[0]; + *out_size = storage_ix >> 3; + return BROTLI_TRUE; + } +} + +/* Dumps remaining output bits and metadata header to |header|. + Returns number of produced bytes. + REQUIRED: |header| should be 8-byte aligned and at least 16 bytes long. + REQUIRED: |block_size| <= (1 << 24). */ +static size_t WriteMetadataHeader( + BrotliEncoderState* s, const size_t block_size, uint8_t* header) { + size_t storage_ix; + storage_ix = s->last_bytes_bits_; + header[0] = (uint8_t)s->last_bytes_; + header[1] = (uint8_t)(s->last_bytes_ >> 8); + s->last_bytes_ = 0; + s->last_bytes_bits_ = 0; + + BrotliWriteBits(1, 0, &storage_ix, header); + BrotliWriteBits(2, 3, &storage_ix, header); + BrotliWriteBits(1, 0, &storage_ix, header); + if (block_size == 0) { + BrotliWriteBits(2, 0, &storage_ix, header); + } else { + uint32_t nbits = (block_size == 1) ? 0 : + (Log2FloorNonZero((uint32_t)block_size - 1) + 1); + uint32_t nbytes = (nbits + 7) / 8; + BrotliWriteBits(2, nbytes, &storage_ix, header); + BrotliWriteBits(8 * nbytes, block_size - 1, &storage_ix, header); + } + return (storage_ix + 7u) >> 3; +} + +static BROTLI_BOOL BrotliCompressBufferQuality10( + int lgwin, size_t input_size, const uint8_t* input_buffer, + size_t* encoded_size, uint8_t* encoded_buffer) { + MemoryManager memory_manager; + MemoryManager* m = &memory_manager; + + const size_t mask = BROTLI_SIZE_MAX >> 1; + int dist_cache[4] = { 4, 11, 15, 16 }; + int saved_dist_cache[4] = { 4, 11, 15, 16 }; + BROTLI_BOOL ok = BROTLI_TRUE; + const size_t max_out_size = *encoded_size; + size_t total_out_size = 0; + uint16_t last_bytes; + uint8_t last_bytes_bits; + HasherHandle hasher = NULL; + + const size_t hasher_eff_size = BROTLI_MIN(size_t, + input_size, BROTLI_MAX_BACKWARD_LIMIT(lgwin) + BROTLI_WINDOW_GAP); + + BrotliEncoderParams params; + + const int lgmetablock = BROTLI_MIN(int, 24, lgwin + 1); + size_t max_block_size; + const size_t max_metablock_size = (size_t)1 << lgmetablock; + const size_t max_literals_per_metablock = max_metablock_size / 8; + const size_t max_commands_per_metablock = max_metablock_size / 8; + size_t metablock_start = 0; + uint8_t prev_byte = 0; + uint8_t prev_byte2 = 0; + + BrotliEncoderInitParams(¶ms); + params.quality = 10; + params.lgwin = lgwin; + if (lgwin > BROTLI_MAX_WINDOW_BITS) { + params.large_window = BROTLI_TRUE; + } + SanitizeParams(¶ms); + params.lgblock = ComputeLgBlock(¶ms); + ChooseDistanceParams(¶ms); + max_block_size = (size_t)1 << params.lgblock; + + BrotliInitMemoryManager(m, 0, 0, 0); + + BROTLI_DCHECK(input_size <= mask + 1); + EncodeWindowBits(lgwin, params.large_window, &last_bytes, &last_bytes_bits); + InitOrStitchToPreviousBlock(m, &hasher, input_buffer, mask, ¶ms, + 0, hasher_eff_size, BROTLI_TRUE); + if (BROTLI_IS_OOM(m)) goto oom; + + while (ok && metablock_start < input_size) { + const size_t metablock_end = + BROTLI_MIN(size_t, input_size, metablock_start + max_metablock_size); + const size_t expected_num_commands = + (metablock_end - metablock_start) / 12 + 16; + Command* commands = 0; + size_t num_commands = 0; + size_t last_insert_len = 0; + size_t num_literals = 0; + size_t metablock_size = 0; + size_t cmd_alloc_size = 0; + BROTLI_BOOL is_last; + uint8_t* storage; + size_t storage_ix; + + ContextType literal_context_mode = ChooseContextMode(¶ms, + input_buffer, metablock_start, mask, metablock_end - metablock_start); + + size_t block_start; + for (block_start = metablock_start; block_start < metablock_end; ) { + size_t block_size = + BROTLI_MIN(size_t, metablock_end - block_start, max_block_size); + ZopfliNode* nodes = BROTLI_ALLOC(m, ZopfliNode, block_size + 1); + size_t path_size; + size_t new_cmd_alloc_size; + if (BROTLI_IS_OOM(m)) goto oom; + BrotliInitZopfliNodes(nodes, block_size + 1); + StitchToPreviousBlockH10(hasher, block_size, block_start, + input_buffer, mask); + path_size = BrotliZopfliComputeShortestPath(m, block_size, block_start, + input_buffer, mask, ¶ms, dist_cache, hasher, + nodes); + if (BROTLI_IS_OOM(m)) goto oom; + /* We allocate a command buffer in the first iteration of this loop that + will be likely big enough for the whole metablock, so that for most + inputs we will not have to reallocate in later iterations. We do the + allocation here and not before the loop, because if the input is small, + this will be allocated after the Zopfli cost model is freed, so this + will not increase peak memory usage. + TODO: If the first allocation is too small, increase command + buffer size exponentially. */ + new_cmd_alloc_size = BROTLI_MAX(size_t, expected_num_commands, + num_commands + path_size + 1); + if (cmd_alloc_size != new_cmd_alloc_size) { + Command* new_commands = BROTLI_ALLOC(m, Command, new_cmd_alloc_size); + if (BROTLI_IS_OOM(m)) goto oom; + cmd_alloc_size = new_cmd_alloc_size; + if (commands) { + memcpy(new_commands, commands, sizeof(Command) * num_commands); + BROTLI_FREE(m, commands); + } + commands = new_commands; + } + BrotliZopfliCreateCommands(block_size, block_start, &nodes[0], dist_cache, + &last_insert_len, ¶ms, &commands[num_commands], &num_literals); + num_commands += path_size; + block_start += block_size; + metablock_size += block_size; + BROTLI_FREE(m, nodes); + if (num_literals > max_literals_per_metablock || + num_commands > max_commands_per_metablock) { + break; + } + } + + if (last_insert_len > 0) { + InitInsertCommand(&commands[num_commands++], last_insert_len); + num_literals += last_insert_len; + } + + is_last = TO_BROTLI_BOOL(metablock_start + metablock_size == input_size); + storage = NULL; + storage_ix = last_bytes_bits; + + if (metablock_size == 0) { + /* Write the ISLAST and ISEMPTY bits. */ + storage = BROTLI_ALLOC(m, uint8_t, 16); + if (BROTLI_IS_OOM(m)) goto oom; + storage[0] = (uint8_t)last_bytes; + storage[1] = (uint8_t)(last_bytes >> 8); + BrotliWriteBits(2, 3, &storage_ix, storage); + storage_ix = (storage_ix + 7u) & ~7u; + } else if (!ShouldCompress(input_buffer, mask, metablock_start, + metablock_size, num_literals, num_commands)) { + /* Restore the distance cache, as its last update by + CreateBackwardReferences is now unused. */ + memcpy(dist_cache, saved_dist_cache, 4 * sizeof(dist_cache[0])); + storage = BROTLI_ALLOC(m, uint8_t, metablock_size + 16); + if (BROTLI_IS_OOM(m)) goto oom; + storage[0] = (uint8_t)last_bytes; + storage[1] = (uint8_t)(last_bytes >> 8); + BrotliStoreUncompressedMetaBlock(is_last, input_buffer, + metablock_start, mask, metablock_size, + &storage_ix, storage); + } else { + MetaBlockSplit mb; + BrotliEncoderParams block_params = params; + InitMetaBlockSplit(&mb); + BrotliBuildMetaBlock(m, input_buffer, metablock_start, mask, + &block_params, + prev_byte, prev_byte2, + commands, num_commands, + literal_context_mode, + &mb); + if (BROTLI_IS_OOM(m)) goto oom; + { + /* The number of distance symbols effectively used for distance + histograms. It might be less than distance alphabet size + for "Large Window Brotli" (32-bit). */ + uint32_t num_effective_dist_codes = block_params.dist.alphabet_size; + if (num_effective_dist_codes > BROTLI_NUM_HISTOGRAM_DISTANCE_SYMBOLS) { + num_effective_dist_codes = BROTLI_NUM_HISTOGRAM_DISTANCE_SYMBOLS; + } + BrotliOptimizeHistograms(num_effective_dist_codes, &mb); + } + storage = BROTLI_ALLOC(m, uint8_t, 2 * metablock_size + 503); + if (BROTLI_IS_OOM(m)) goto oom; + storage[0] = (uint8_t)last_bytes; + storage[1] = (uint8_t)(last_bytes >> 8); + BrotliStoreMetaBlock(m, input_buffer, metablock_start, metablock_size, + mask, prev_byte, prev_byte2, + is_last, + &block_params, + literal_context_mode, + commands, num_commands, + &mb, + &storage_ix, storage); + if (BROTLI_IS_OOM(m)) goto oom; + if (metablock_size + 4 < (storage_ix >> 3)) { + /* Restore the distance cache and last byte. */ + memcpy(dist_cache, saved_dist_cache, 4 * sizeof(dist_cache[0])); + storage[0] = (uint8_t)last_bytes; + storage[1] = (uint8_t)(last_bytes >> 8); + storage_ix = last_bytes_bits; + BrotliStoreUncompressedMetaBlock(is_last, input_buffer, + metablock_start, mask, + metablock_size, &storage_ix, storage); + } + DestroyMetaBlockSplit(m, &mb); + } + last_bytes = (uint16_t)(storage[storage_ix >> 3]); + last_bytes_bits = storage_ix & 7u; + metablock_start += metablock_size; + if (metablock_start < input_size) { + prev_byte = input_buffer[metablock_start - 1]; + prev_byte2 = input_buffer[metablock_start - 2]; + } + /* Save the state of the distance cache in case we need to restore it for + emitting an uncompressed block. */ + memcpy(saved_dist_cache, dist_cache, 4 * sizeof(dist_cache[0])); + + { + const size_t out_size = storage_ix >> 3; + total_out_size += out_size; + if (total_out_size <= max_out_size) { + memcpy(encoded_buffer, storage, out_size); + encoded_buffer += out_size; + } else { + ok = BROTLI_FALSE; + } + } + BROTLI_FREE(m, storage); + BROTLI_FREE(m, commands); + } + + *encoded_size = total_out_size; + DestroyHasher(m, &hasher); + return ok; + +oom: + BrotliWipeOutMemoryManager(m); + return BROTLI_FALSE; +} + +size_t BrotliEncoderMaxCompressedSize(size_t input_size) { + /* [window bits / empty metadata] + N * [uncompressed] + [last empty] */ + size_t num_large_blocks = input_size >> 14; + size_t overhead = 2 + (4 * num_large_blocks) + 3 + 1; + size_t result = input_size + overhead; + if (input_size == 0) return 2; + return (result < input_size) ? 0 : result; +} + +/* Wraps data to uncompressed brotli stream with minimal window size. + |output| should point at region with at least BrotliEncoderMaxCompressedSize + addressable bytes. + Returns the length of stream. */ +static size_t MakeUncompressedStream( + const uint8_t* input, size_t input_size, uint8_t* output) { + size_t size = input_size; + size_t result = 0; + size_t offset = 0; + if (input_size == 0) { + output[0] = 6; + return 1; + } + output[result++] = 0x21; /* window bits = 10, is_last = false */ + output[result++] = 0x03; /* empty metadata, padding */ + while (size > 0) { + uint32_t nibbles = 0; + uint32_t chunk_size; + uint32_t bits; + chunk_size = (size > (1u << 24)) ? (1u << 24) : (uint32_t)size; + if (chunk_size > (1u << 16)) nibbles = (chunk_size > (1u << 20)) ? 2 : 1; + bits = + (nibbles << 1) | ((chunk_size - 1) << 3) | (1u << (19 + 4 * nibbles)); + output[result++] = (uint8_t)bits; + output[result++] = (uint8_t)(bits >> 8); + output[result++] = (uint8_t)(bits >> 16); + if (nibbles == 2) output[result++] = (uint8_t)(bits >> 24); + memcpy(&output[result], &input[offset], chunk_size); + result += chunk_size; + offset += chunk_size; + size -= chunk_size; + } + output[result++] = 3; + return result; +} + +BROTLI_BOOL BrotliEncoderCompress( + int quality, int lgwin, BrotliEncoderMode mode, size_t input_size, + const uint8_t* input_buffer, size_t* encoded_size, + uint8_t* encoded_buffer) { + BrotliEncoderState* s; + size_t out_size = *encoded_size; + const uint8_t* input_start = input_buffer; + uint8_t* output_start = encoded_buffer; + size_t max_out_size = BrotliEncoderMaxCompressedSize(input_size); + if (out_size == 0) { + /* Output buffer needs at least one byte. */ + return BROTLI_FALSE; + } + if (input_size == 0) { + /* Handle the special case of empty input. */ + *encoded_size = 1; + *encoded_buffer = 6; + return BROTLI_TRUE; + } + if (quality == 10) { + /* TODO: Implement this direct path for all quality levels. */ + const int lg_win = BROTLI_MIN(int, BROTLI_LARGE_MAX_WINDOW_BITS, + BROTLI_MAX(int, 16, lgwin)); + int ok = BrotliCompressBufferQuality10(lg_win, input_size, input_buffer, + encoded_size, encoded_buffer); + if (!ok || (max_out_size && *encoded_size > max_out_size)) { + goto fallback; + } + return BROTLI_TRUE; + } + + s = BrotliEncoderCreateInstance(0, 0, 0); + if (!s) { + return BROTLI_FALSE; + } else { + size_t available_in = input_size; + const uint8_t* next_in = input_buffer; + size_t available_out = *encoded_size; + uint8_t* next_out = encoded_buffer; + size_t total_out = 0; + BROTLI_BOOL result = BROTLI_FALSE; + BrotliEncoderSetParameter(s, BROTLI_PARAM_QUALITY, (uint32_t)quality); + BrotliEncoderSetParameter(s, BROTLI_PARAM_LGWIN, (uint32_t)lgwin); + BrotliEncoderSetParameter(s, BROTLI_PARAM_MODE, (uint32_t)mode); + BrotliEncoderSetParameter(s, BROTLI_PARAM_SIZE_HINT, (uint32_t)input_size); + if (lgwin > BROTLI_MAX_WINDOW_BITS) { + BrotliEncoderSetParameter(s, BROTLI_PARAM_LARGE_WINDOW, BROTLI_TRUE); + } + result = BrotliEncoderCompressStream(s, BROTLI_OPERATION_FINISH, + &available_in, &next_in, &available_out, &next_out, &total_out); + if (!BrotliEncoderIsFinished(s)) result = 0; + *encoded_size = total_out; + BrotliEncoderDestroyInstance(s); + if (!result || (max_out_size && *encoded_size > max_out_size)) { + goto fallback; + } + return BROTLI_TRUE; + } +fallback: + *encoded_size = 0; + if (!max_out_size) return BROTLI_FALSE; + if (out_size >= max_out_size) { + *encoded_size = + MakeUncompressedStream(input_start, input_size, output_start); + return BROTLI_TRUE; + } + return BROTLI_FALSE; +} + +static void InjectBytePaddingBlock(BrotliEncoderState* s) { + uint32_t seal = s->last_bytes_; + size_t seal_bits = s->last_bytes_bits_; + uint8_t* destination; + s->last_bytes_ = 0; + s->last_bytes_bits_ = 0; + /* is_last = 0, data_nibbles = 11, reserved = 0, meta_nibbles = 00 */ + seal |= 0x6u << seal_bits; + seal_bits += 6; + /* If we have already created storage, then append to it. + Storage is valid until next block is being compressed. */ + if (s->next_out_) { + destination = s->next_out_ + s->available_out_; + } else { + destination = s->tiny_buf_.u8; + s->next_out_ = destination; + } + destination[0] = (uint8_t)seal; + if (seal_bits > 8) destination[1] = (uint8_t)(seal >> 8); + if (seal_bits > 16) destination[2] = (uint8_t)(seal >> 16); + s->available_out_ += (seal_bits + 7) >> 3; +} + +/* Injects padding bits or pushes compressed data to output. + Returns false if nothing is done. */ +static BROTLI_BOOL InjectFlushOrPushOutput(BrotliEncoderState* s, + size_t* available_out, uint8_t** next_out, size_t* total_out) { + if (s->stream_state_ == BROTLI_STREAM_FLUSH_REQUESTED && + s->last_bytes_bits_ != 0) { + InjectBytePaddingBlock(s); + return BROTLI_TRUE; + } + + if (s->available_out_ != 0 && *available_out != 0) { + size_t copy_output_size = + BROTLI_MIN(size_t, s->available_out_, *available_out); + memcpy(*next_out, s->next_out_, copy_output_size); + *next_out += copy_output_size; + *available_out -= copy_output_size; + s->next_out_ += copy_output_size; + s->available_out_ -= copy_output_size; + s->total_out_ += copy_output_size; + if (total_out) *total_out = s->total_out_; + return BROTLI_TRUE; + } + + return BROTLI_FALSE; +} + +static void CheckFlushComplete(BrotliEncoderState* s) { + if (s->stream_state_ == BROTLI_STREAM_FLUSH_REQUESTED && + s->available_out_ == 0) { + s->stream_state_ = BROTLI_STREAM_PROCESSING; + s->next_out_ = 0; + } +} + +static BROTLI_BOOL BrotliEncoderCompressStreamFast( + BrotliEncoderState* s, BrotliEncoderOperation op, size_t* available_in, + const uint8_t** next_in, size_t* available_out, uint8_t** next_out, + size_t* total_out) { + const size_t block_size_limit = (size_t)1 << s->params.lgwin; + const size_t buf_size = BROTLI_MIN(size_t, kCompressFragmentTwoPassBlockSize, + BROTLI_MIN(size_t, *available_in, block_size_limit)); + uint32_t* tmp_command_buf = NULL; + uint32_t* command_buf = NULL; + uint8_t* tmp_literal_buf = NULL; + uint8_t* literal_buf = NULL; + MemoryManager* m = &s->memory_manager_; + if (s->params.quality != FAST_ONE_PASS_COMPRESSION_QUALITY && + s->params.quality != FAST_TWO_PASS_COMPRESSION_QUALITY) { + return BROTLI_FALSE; + } + if (s->params.quality == FAST_TWO_PASS_COMPRESSION_QUALITY) { + if (!s->command_buf_ && buf_size == kCompressFragmentTwoPassBlockSize) { + s->command_buf_ = + BROTLI_ALLOC(m, uint32_t, kCompressFragmentTwoPassBlockSize); + s->literal_buf_ = + BROTLI_ALLOC(m, uint8_t, kCompressFragmentTwoPassBlockSize); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + } + if (s->command_buf_) { + command_buf = s->command_buf_; + literal_buf = s->literal_buf_; + } else { + tmp_command_buf = BROTLI_ALLOC(m, uint32_t, buf_size); + tmp_literal_buf = BROTLI_ALLOC(m, uint8_t, buf_size); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + command_buf = tmp_command_buf; + literal_buf = tmp_literal_buf; + } + } + + while (BROTLI_TRUE) { + if (InjectFlushOrPushOutput(s, available_out, next_out, total_out)) { + continue; + } + + /* Compress block only when internal output buffer is empty, stream is not + finished, there is no pending flush request, and there is either + additional input or pending operation. */ + if (s->available_out_ == 0 && + s->stream_state_ == BROTLI_STREAM_PROCESSING && + (*available_in != 0 || op != BROTLI_OPERATION_PROCESS)) { + size_t block_size = BROTLI_MIN(size_t, block_size_limit, *available_in); + BROTLI_BOOL is_last = + (*available_in == block_size) && (op == BROTLI_OPERATION_FINISH); + BROTLI_BOOL force_flush = + (*available_in == block_size) && (op == BROTLI_OPERATION_FLUSH); + size_t max_out_size = 2 * block_size + 503; + BROTLI_BOOL inplace = BROTLI_TRUE; + uint8_t* storage = NULL; + size_t storage_ix = s->last_bytes_bits_; + size_t table_size; + int* table; + + if (force_flush && block_size == 0) { + s->stream_state_ = BROTLI_STREAM_FLUSH_REQUESTED; + continue; + } + if (max_out_size <= *available_out) { + storage = *next_out; + } else { + inplace = BROTLI_FALSE; + storage = GetBrotliStorage(s, max_out_size); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + } + storage[0] = (uint8_t)s->last_bytes_; + storage[1] = (uint8_t)(s->last_bytes_ >> 8); + table = GetHashTable(s, s->params.quality, block_size, &table_size); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + + if (s->params.quality == FAST_ONE_PASS_COMPRESSION_QUALITY) { + BrotliCompressFragmentFast(m, *next_in, block_size, is_last, table, + table_size, s->cmd_depths_, s->cmd_bits_, &s->cmd_code_numbits_, + s->cmd_code_, &storage_ix, storage); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + } else { + BrotliCompressFragmentTwoPass(m, *next_in, block_size, is_last, + command_buf, literal_buf, table, table_size, + &storage_ix, storage); + if (BROTLI_IS_OOM(m)) return BROTLI_FALSE; + } + *next_in += block_size; + *available_in -= block_size; + if (inplace) { + size_t out_bytes = storage_ix >> 3; + BROTLI_DCHECK(out_bytes <= *available_out); + BROTLI_DCHECK((storage_ix & 7) == 0 || out_bytes < *available_out); + *next_out += out_bytes; + *available_out -= out_bytes; + s->total_out_ += out_bytes; + if (total_out) *total_out = s->total_out_; + } else { + size_t out_bytes = storage_ix >> 3; + s->next_out_ = storage; + s->available_out_ = out_bytes; + } + s->last_bytes_ = (uint16_t)(storage[storage_ix >> 3]); + s->last_bytes_bits_ = storage_ix & 7u; + + if (force_flush) s->stream_state_ = BROTLI_STREAM_FLUSH_REQUESTED; + if (is_last) s->stream_state_ = BROTLI_STREAM_FINISHED; + continue; + } + break; + } + BROTLI_FREE(m, tmp_command_buf); + BROTLI_FREE(m, tmp_literal_buf); + CheckFlushComplete(s); + return BROTLI_TRUE; +} + +static BROTLI_BOOL ProcessMetadata( + BrotliEncoderState* s, size_t* available_in, const uint8_t** next_in, + size_t* available_out, uint8_t** next_out, size_t* total_out) { + if (*available_in > (1u << 24)) return BROTLI_FALSE; + /* Switch to metadata block workflow, if required. */ + if (s->stream_state_ == BROTLI_STREAM_PROCESSING) { + s->remaining_metadata_bytes_ = (uint32_t)*available_in; + s->stream_state_ = BROTLI_STREAM_METADATA_HEAD; + } + if (s->stream_state_ != BROTLI_STREAM_METADATA_HEAD && + s->stream_state_ != BROTLI_STREAM_METADATA_BODY) { + return BROTLI_FALSE; + } + + while (BROTLI_TRUE) { + if (InjectFlushOrPushOutput(s, available_out, next_out, total_out)) { + continue; + } + if (s->available_out_ != 0) break; + + if (s->input_pos_ != s->last_flush_pos_) { + BROTLI_BOOL result = EncodeData(s, BROTLI_FALSE, BROTLI_TRUE, + &s->available_out_, &s->next_out_); + if (!result) return BROTLI_FALSE; + continue; + } + + if (s->stream_state_ == BROTLI_STREAM_METADATA_HEAD) { + s->next_out_ = s->tiny_buf_.u8; + s->available_out_ = + WriteMetadataHeader(s, s->remaining_metadata_bytes_, s->next_out_); + s->stream_state_ = BROTLI_STREAM_METADATA_BODY; + continue; + } else { + /* Exit workflow only when there is no more input and no more output. + Otherwise client may continue producing empty metadata blocks. */ + if (s->remaining_metadata_bytes_ == 0) { + s->remaining_metadata_bytes_ = BROTLI_UINT32_MAX; + s->stream_state_ = BROTLI_STREAM_PROCESSING; + break; + } + if (*available_out) { + /* Directly copy input to output. */ + uint32_t copy = (uint32_t)BROTLI_MIN( + size_t, s->remaining_metadata_bytes_, *available_out); + memcpy(*next_out, *next_in, copy); + *next_in += copy; + *available_in -= copy; + s->remaining_metadata_bytes_ -= copy; + *next_out += copy; + *available_out -= copy; + } else { + /* This guarantees progress in "TakeOutput" workflow. */ + uint32_t copy = BROTLI_MIN(uint32_t, s->remaining_metadata_bytes_, 16); + s->next_out_ = s->tiny_buf_.u8; + memcpy(s->next_out_, *next_in, copy); + *next_in += copy; + *available_in -= copy; + s->remaining_metadata_bytes_ -= copy; + s->available_out_ = copy; + } + continue; + } + } + + return BROTLI_TRUE; +} + +static void UpdateSizeHint(BrotliEncoderState* s, size_t available_in) { + if (s->params.size_hint == 0) { + uint64_t delta = UnprocessedInputSize(s); + uint64_t tail = available_in; + uint32_t limit = 1u << 30; + uint32_t total; + if ((delta >= limit) || (tail >= limit) || ((delta + tail) >= limit)) { + total = limit; + } else { + total = (uint32_t)(delta + tail); + } + s->params.size_hint = total; + } +} + +BROTLI_BOOL BrotliEncoderCompressStream( + BrotliEncoderState* s, BrotliEncoderOperation op, size_t* available_in, + const uint8_t** next_in, size_t* available_out,uint8_t** next_out, + size_t* total_out) { + if (!EnsureInitialized(s)) return BROTLI_FALSE; + + /* Unfinished metadata block; check requirements. */ + if (s->remaining_metadata_bytes_ != BROTLI_UINT32_MAX) { + if (*available_in != s->remaining_metadata_bytes_) return BROTLI_FALSE; + if (op != BROTLI_OPERATION_EMIT_METADATA) return BROTLI_FALSE; + } + + if (op == BROTLI_OPERATION_EMIT_METADATA) { + UpdateSizeHint(s, 0); /* First data metablock might be emitted here. */ + return ProcessMetadata( + s, available_in, next_in, available_out, next_out, total_out); + } + + if (s->stream_state_ == BROTLI_STREAM_METADATA_HEAD || + s->stream_state_ == BROTLI_STREAM_METADATA_BODY) { + return BROTLI_FALSE; + } + + if (s->stream_state_ != BROTLI_STREAM_PROCESSING && *available_in != 0) { + return BROTLI_FALSE; + } + if (s->params.quality == FAST_ONE_PASS_COMPRESSION_QUALITY || + s->params.quality == FAST_TWO_PASS_COMPRESSION_QUALITY) { + return BrotliEncoderCompressStreamFast(s, op, available_in, next_in, + available_out, next_out, total_out); + } + while (BROTLI_TRUE) { + size_t remaining_block_size = RemainingInputBlockSize(s); + + if (remaining_block_size != 0 && *available_in != 0) { + size_t copy_input_size = + BROTLI_MIN(size_t, remaining_block_size, *available_in); + CopyInputToRingBuffer(s, copy_input_size, *next_in); + *next_in += copy_input_size; + *available_in -= copy_input_size; + continue; + } + + if (InjectFlushOrPushOutput(s, available_out, next_out, total_out)) { + continue; + } + + /* Compress data only when internal output buffer is empty, stream is not + finished and there is no pending flush request. */ + if (s->available_out_ == 0 && + s->stream_state_ == BROTLI_STREAM_PROCESSING) { + if (remaining_block_size == 0 || op != BROTLI_OPERATION_PROCESS) { + BROTLI_BOOL is_last = TO_BROTLI_BOOL( + (*available_in == 0) && op == BROTLI_OPERATION_FINISH); + BROTLI_BOOL force_flush = TO_BROTLI_BOOL( + (*available_in == 0) && op == BROTLI_OPERATION_FLUSH); + BROTLI_BOOL result; + UpdateSizeHint(s, *available_in); + result = EncodeData(s, is_last, force_flush, + &s->available_out_, &s->next_out_); + if (!result) return BROTLI_FALSE; + if (force_flush) s->stream_state_ = BROTLI_STREAM_FLUSH_REQUESTED; + if (is_last) s->stream_state_ = BROTLI_STREAM_FINISHED; + continue; + } + } + break; + } + CheckFlushComplete(s); + return BROTLI_TRUE; +} + +BROTLI_BOOL BrotliEncoderIsFinished(BrotliEncoderState* s) { + return TO_BROTLI_BOOL(s->stream_state_ == BROTLI_STREAM_FINISHED && + !BrotliEncoderHasMoreOutput(s)); +} + +BROTLI_BOOL BrotliEncoderHasMoreOutput(BrotliEncoderState* s) { + return TO_BROTLI_BOOL(s->available_out_ != 0); +} + +const uint8_t* BrotliEncoderTakeOutput(BrotliEncoderState* s, size_t* size) { + size_t consumed_size = s->available_out_; + uint8_t* result = s->next_out_; + if (*size) { + consumed_size = BROTLI_MIN(size_t, *size, s->available_out_); + } + if (consumed_size) { + s->next_out_ += consumed_size; + s->available_out_ -= consumed_size; + s->total_out_ += consumed_size; + CheckFlushComplete(s); + *size = consumed_size; + } else { + *size = 0; + result = 0; + } + return result; +} + +uint32_t BrotliEncoderVersion(void) { + return BROTLI_VERSION; +} + +#if defined(__cplusplus) || defined(c_plusplus) +} /* extern "C" */ +#endif |