diff options
Diffstat (limited to 'modules/brotli/dec/decode.c')
| -rw-r--r-- | modules/brotli/dec/decode.c | 2262 |
1 files changed, 2262 insertions, 0 deletions
diff --git a/modules/brotli/dec/decode.c b/modules/brotli/dec/decode.c new file mode 100644 index 000000000..d184f24cb --- /dev/null +++ b/modules/brotli/dec/decode.c @@ -0,0 +1,2262 @@ +/* Copyright 2013 Google Inc. All Rights Reserved. + + Distributed under MIT license. + See file LICENSE for detail or copy at https://opensource.org/licenses/MIT +*/ + +#include "./decode.h" + +#ifdef __ARM_NEON__ +#include <arm_neon.h> +#endif + +#include <stdlib.h> /* free, malloc */ +#include <string.h> /* memcpy, memset */ + +#include "./bit_reader.h" +#include "./context.h" +#include "./dictionary.h" +#include "./huffman.h" +#include "./port.h" +#include "./prefix.h" +#include "./state.h" +#include "./transform.h" + +#if defined(__cplusplus) || defined(c_plusplus) +extern "C" { +#endif + +#define BROTLI_FAILURE(CODE) (BROTLI_DUMP(), CODE) + +#define BROTLI_LOG_UINT(name) \ + BROTLI_LOG(("[%s] %s = %lu\n", __func__, #name, (unsigned long)(name))) +#define BROTLI_LOG_ARRAY_INDEX(array_name, idx) \ + BROTLI_LOG(("[%s] %s[%lu] = %lu\n", __func__, #array_name, \ + (unsigned long)(idx), (unsigned long)array_name[idx])) + +static const uint32_t kDefaultCodeLength = 8; +static const uint32_t kCodeLengthRepeatCode = 16; +static const uint32_t kNumLiteralCodes = 256; +static const uint32_t kNumInsertAndCopyCodes = 704; +static const uint32_t kNumBlockLengthCodes = 26; +static const int kLiteralContextBits = 6; +static const int kDistanceContextBits = 2; + +#define HUFFMAN_TABLE_BITS 8U +#define HUFFMAN_TABLE_MASK 0xff + +#define CODE_LENGTH_CODES 18 +static const uint8_t kCodeLengthCodeOrder[CODE_LENGTH_CODES] = { + 1, 2, 3, 4, 0, 5, 17, 6, 16, 7, 8, 9, 10, 11, 12, 13, 14, 15, +}; + +/* Static prefix code for the complex code length code lengths. */ +static const uint8_t kCodeLengthPrefixLength[16] = { + 2, 2, 2, 3, 2, 2, 2, 4, 2, 2, 2, 3, 2, 2, 2, 4, +}; + +static const uint8_t kCodeLengthPrefixValue[16] = { + 0, 4, 3, 2, 0, 4, 3, 1, 0, 4, 3, 2, 0, 4, 3, 5, +}; + +#define NUM_DISTANCE_SHORT_CODES 16 + +BrotliState* BrotliCreateState( + brotli_alloc_func alloc_func, brotli_free_func free_func, void* opaque) { + BrotliState* state = 0; + if (!alloc_func && !free_func) { + state = (BrotliState*)malloc(sizeof(BrotliState)); + } else if (alloc_func && free_func) { + state = (BrotliState*)alloc_func(opaque, sizeof(BrotliState)); + } + if (state == 0) { + BROTLI_DUMP(); + return 0; + } + BrotliStateInitWithCustomAllocators(state, alloc_func, free_func, opaque); + state->error_code = BROTLI_NO_ERROR; + return state; +} + +/* Deinitializes and frees BrotliState instance. */ +void BrotliDestroyState(BrotliState* state) { + if (!state) { + return; + } else { + brotli_free_func free_func = state->free_func; + void* opaque = state->memory_manager_opaque; + BrotliStateCleanup(state); + free_func(opaque, state); + } +} + +/* Saves error code and converts it to BrotliResult */ +static BROTLI_NOINLINE BrotliResult SaveErrorCode( + BrotliState* s, BrotliErrorCode e) { + s->error_code = (int)e; + switch (e) { + case BROTLI_SUCCESS: return BROTLI_RESULT_SUCCESS; + case BROTLI_NEEDS_MORE_INPUT: return BROTLI_RESULT_NEEDS_MORE_INPUT; + case BROTLI_NEEDS_MORE_OUTPUT: return BROTLI_RESULT_NEEDS_MORE_OUTPUT; + default: return BROTLI_RESULT_ERROR; + } +} + +/* Decodes a number in the range [9..24], by reading 1 - 7 bits. + Precondition: bit-reader accumulator has at least 7 bits. */ +static uint32_t DecodeWindowBits(BrotliBitReader* br) { + uint32_t n; + BrotliTakeBits(br, 1, &n); + if (n == 0) { + return 16; + } + BrotliTakeBits(br, 3, &n); + if (n != 0) { + return 17 + n; + } + BrotliTakeBits(br, 3, &n); + if (n != 0) { + return 8 + n; + } + return 17; +} + +static BROTLI_INLINE void memmove16(uint8_t* dst, uint8_t* src) { +#if defined(__ARM_NEON__) + vst1q_u8(dst, vld1q_u8(src)); +#else + uint32_t buffer[4]; + memcpy(buffer, src, 16); + memcpy(dst, buffer, 16); +#endif +} + +/* Decodes a number in the range [0..255], by reading 1 - 11 bits. */ +static BROTLI_NOINLINE BrotliErrorCode DecodeVarLenUint8(BrotliState* s, + BrotliBitReader* br, uint32_t* value) { + uint32_t bits; + switch (s->substate_decode_uint8) { + case BROTLI_STATE_DECODE_UINT8_NONE: + if (PREDICT_FALSE(!BrotliSafeReadBits(br, 1, &bits))) { + return BROTLI_NEEDS_MORE_INPUT; + } + if (bits == 0) { + *value = 0; + return BROTLI_SUCCESS; + } + /* No break, transit to the next state. */ + + case BROTLI_STATE_DECODE_UINT8_SHORT: + if (PREDICT_FALSE(!BrotliSafeReadBits(br, 3, &bits))) { + s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_SHORT; + return BROTLI_NEEDS_MORE_INPUT; + } + if (bits == 0) { + *value = 1; + s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_NONE; + return BROTLI_SUCCESS; + } + /* Use output value as a temporary storage. It MUST be persisted. */ + *value = bits; + /* No break, transit to the next state. */ + + case BROTLI_STATE_DECODE_UINT8_LONG: + if (PREDICT_FALSE(!BrotliSafeReadBits(br, *value, &bits))) { + s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_LONG; + return BROTLI_NEEDS_MORE_INPUT; + } + *value = (1U << *value) + bits; + s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_NONE; + return BROTLI_SUCCESS; + + default: + return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE); + } +} + +/* Decodes a metablock length and flags by reading 2 - 31 bits. */ +static BrotliErrorCode BROTLI_NOINLINE DecodeMetaBlockLength( + BrotliState* s, BrotliBitReader* br) { + uint32_t bits; + int i; + for (;;) { + switch (s->substate_metablock_header) { + case BROTLI_STATE_METABLOCK_HEADER_NONE: + if (!BrotliSafeReadBits(br, 1, &bits)) { + return BROTLI_NEEDS_MORE_INPUT; + } + s->is_last_metablock = (uint8_t)bits; + s->meta_block_remaining_len = 0; + s->is_uncompressed = 0; + s->is_metadata = 0; + if (!s->is_last_metablock) { + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NIBBLES; + break; + } + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_EMPTY; + /* No break, transit to the next state. */ + + case BROTLI_STATE_METABLOCK_HEADER_EMPTY: + if (!BrotliSafeReadBits(br, 1, &bits)) { + return BROTLI_NEEDS_MORE_INPUT; + } + if (bits) { + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE; + return BROTLI_SUCCESS; + } + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NIBBLES; + /* No break, transit to the next state. */ + + case BROTLI_STATE_METABLOCK_HEADER_NIBBLES: + if (!BrotliSafeReadBits(br, 2, &bits)) { + return BROTLI_NEEDS_MORE_INPUT; + } + s->size_nibbles = (uint8_t)(bits + 4); + s->loop_counter = 0; + if (bits == 3) { + s->is_metadata = 1; + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_RESERVED; + break; + } + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_SIZE; + /* No break, transit to the next state. */ + + case BROTLI_STATE_METABLOCK_HEADER_SIZE: + i = s->loop_counter; + for (; i < s->size_nibbles; ++i) { + if (!BrotliSafeReadBits(br, 4, &bits)) { + s->loop_counter = i; + return BROTLI_NEEDS_MORE_INPUT; + } + if (i + 1 == s->size_nibbles && s->size_nibbles > 4 && bits == 0) { + return BROTLI_FAILURE(BROTLI_ERROR_FORMAT_EXUBERANT_NIBBLE); + } + s->meta_block_remaining_len |= (int)(bits << (i * 4)); + } + s->substate_metablock_header = + BROTLI_STATE_METABLOCK_HEADER_UNCOMPRESSED; + /* No break, transit to the next state. */ + + case BROTLI_STATE_METABLOCK_HEADER_UNCOMPRESSED: + if (!s->is_last_metablock) { + if (!BrotliSafeReadBits(br, 1, &bits)) { + return BROTLI_NEEDS_MORE_INPUT; + } + s->is_uncompressed = (uint8_t)bits; + } + ++s->meta_block_remaining_len; + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE; + return BROTLI_SUCCESS; + + case BROTLI_STATE_METABLOCK_HEADER_RESERVED: + if (!BrotliSafeReadBits(br, 1, &bits)) { + return BROTLI_NEEDS_MORE_INPUT; + } + if (bits != 0) { + return BROTLI_FAILURE(BROTLI_ERROR_FORMAT_RESERVED); + } + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_BYTES; + /* No break, transit to the next state. */ + + case BROTLI_STATE_METABLOCK_HEADER_BYTES: + if (!BrotliSafeReadBits(br, 2, &bits)) { + return BROTLI_NEEDS_MORE_INPUT; + } + if (bits == 0) { + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE; + return BROTLI_SUCCESS; + } + s->size_nibbles = (uint8_t)bits; + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_METADATA; + /* No break, transit to the next state. */ + + case BROTLI_STATE_METABLOCK_HEADER_METADATA: + i = s->loop_counter; + for (; i < s->size_nibbles; ++i) { + if (!BrotliSafeReadBits(br, 8, &bits)) { + s->loop_counter = i; + return BROTLI_NEEDS_MORE_INPUT; + } + if (i + 1 == s->size_nibbles && s->size_nibbles > 1 && bits == 0) { + return BROTLI_FAILURE(BROTLI_ERROR_FORMAT_EXUBERANT_META_NIBBLE); + } + s->meta_block_remaining_len |= (int)(bits << (i * 8)); + } + ++s->meta_block_remaining_len; + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE; + return BROTLI_SUCCESS; + + default: + return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE); + } + } +} + +/* Decodes the Huffman code. + This method doesn't read data from the bit reader, BUT drops the amount of + bits that correspond to the decoded symbol. + bits MUST contain at least 15 (BROTLI_HUFFMAN_MAX_CODE_LENGTH) valid bits. */ +static BROTLI_INLINE uint32_t DecodeSymbol(uint32_t bits, + const HuffmanCode* table, + BrotliBitReader* br) { + table += bits & HUFFMAN_TABLE_MASK; + if (table->bits > HUFFMAN_TABLE_BITS) { + uint32_t nbits = table->bits - HUFFMAN_TABLE_BITS; + BrotliDropBits(br, HUFFMAN_TABLE_BITS); + table += table->value; + table += (bits >> HUFFMAN_TABLE_BITS) & BitMask(nbits); + } + BrotliDropBits(br, table->bits); + return table->value; +} + +/* Reads and decodes the next Huffman code from bit-stream. + This method peeks 16 bits of input and drops 0 - 15 of them. */ +static BROTLI_INLINE uint32_t ReadSymbol(const HuffmanCode* table, + BrotliBitReader* br) { + return DecodeSymbol(BrotliGet16BitsUnmasked(br), table, br); +} + +/* Same as DecodeSymbol, but it is known that there is less than 15 bits of + input are currently available. */ +static BROTLI_NOINLINE int SafeDecodeSymbol(const HuffmanCode* table, + BrotliBitReader* br, + uint32_t* result) { + uint32_t val; + uint32_t available_bits = BrotliGetAvailableBits(br); + if (available_bits == 0) { + if (table->bits == 0) { + *result = table->value; + return 1; + } + return 0; /* No valid bits at all. */ + } + val = (uint32_t)BrotliGetBitsUnmasked(br); + table += val & HUFFMAN_TABLE_MASK; + if (table->bits <= HUFFMAN_TABLE_BITS) { + if (table->bits <= available_bits) { + BrotliDropBits(br, table->bits); + *result = table->value; + return 1; + } else { + return 0; /* Not enough bits for the first level. */ + } + } + if (available_bits <= HUFFMAN_TABLE_BITS) { + return 0; /* Not enough bits to move to the second level. */ + } + + /* Speculatively drop HUFFMAN_TABLE_BITS. */ + val = (val & BitMask(table->bits)) >> HUFFMAN_TABLE_BITS; + available_bits -= HUFFMAN_TABLE_BITS; + table += table->value + val; + if (available_bits < table->bits) { + return 0; /* Not enough bits for the second level. */ + } + + BrotliDropBits(br, HUFFMAN_TABLE_BITS + table->bits); + *result = table->value; + return 1; +} + +static BROTLI_INLINE int SafeReadSymbol(const HuffmanCode* table, + BrotliBitReader* br, + uint32_t* result) { + uint32_t val; + if (PREDICT_TRUE(BrotliSafeGetBits(br, 15, &val))) { + *result = DecodeSymbol(val, table, br); + return 1; + } + return SafeDecodeSymbol(table, br, result); +} + +/* Makes a look-up in first level Huffman table. Peeks 8 bits. */ +static BROTLI_INLINE void PreloadSymbol(int safe, + const HuffmanCode* table, + BrotliBitReader* br, + uint32_t* bits, + uint32_t* value) { + if (safe) { + return; + } + table += BrotliGetBits(br, HUFFMAN_TABLE_BITS); + *bits = table->bits; + *value = table->value; +} + +/* Decodes the next Huffman code using data prepared by PreloadSymbol. + Reads 0 - 15 bits. Also peeks 8 following bits. */ +static BROTLI_INLINE uint32_t ReadPreloadedSymbol(const HuffmanCode* table, + BrotliBitReader* br, + uint32_t* bits, + uint32_t* value) { + uint32_t result = *value; + if (PREDICT_FALSE(*bits > HUFFMAN_TABLE_BITS)) { + uint32_t val = BrotliGet16BitsUnmasked(br); + const HuffmanCode* ext = table + (val & HUFFMAN_TABLE_MASK) + *value; + uint32_t mask = BitMask((*bits - HUFFMAN_TABLE_BITS)); + BrotliDropBits(br, HUFFMAN_TABLE_BITS); + ext += (val >> HUFFMAN_TABLE_BITS) & mask; + BrotliDropBits(br, ext->bits); + result = ext->value; + } else { + BrotliDropBits(br, *bits); + } + PreloadSymbol(0, table, br, bits, value); + return result; +} + +static BROTLI_INLINE uint32_t Log2Floor(uint32_t x) { + uint32_t result = 0; + while (x) { + x >>= 1; + ++result; + } + return result; +} + +/* Reads (s->symbol + 1) symbols. + Totally 1..4 symbols are read, 1..10 bits each. + The list of symbols MUST NOT contain duplicates. + */ +static BrotliErrorCode ReadSimpleHuffmanSymbols(uint32_t alphabet_size, + BrotliState* s) { + /* max_bits == 1..10; symbol == 0..3; 1..40 bits will be read. */ + BrotliBitReader* br = &s->br; + uint32_t max_bits = Log2Floor(alphabet_size - 1); + uint32_t i = s->sub_loop_counter; + uint32_t num_symbols = s->symbol; + while (i <= num_symbols) { + uint32_t v; + if (PREDICT_FALSE(!BrotliSafeReadBits(br, max_bits, &v))) { + s->sub_loop_counter = i; + s->substate_huffman = BROTLI_STATE_HUFFMAN_SIMPLE_READ; + return BROTLI_NEEDS_MORE_INPUT; + } + if (v >= alphabet_size) { + return BROTLI_FAILURE(BROTLI_ERROR_FORMAT_SIMPLE_HUFFMAN_ALPHABET); + } + s->symbols_lists_array[i] = (uint16_t)v; + BROTLI_LOG_UINT(s->symbols_lists_array[i]); + ++i; + } + + for (i = 0; i < num_symbols; ++i) { + uint32_t k = i + 1; + for (; k <= num_symbols; ++k) { + if (s->symbols_lists_array[i] == s->symbols_lists_array[k]) { + return BROTLI_FAILURE(BROTLI_ERROR_FORMAT_SIMPLE_HUFFMAN_SAME); + } + } + } + + return BROTLI_SUCCESS; +} + +/* Process single decoded symbol code length: + A) reset the repeat variable + B) remember code length (if it is not 0) + C) extend corredponding index-chain + D) reduce the huffman space + E) update the histogram + */ +static BROTLI_INLINE void ProcessSingleCodeLength(uint32_t code_len, + uint32_t* symbol, uint32_t* repeat, uint32_t* space, + uint32_t* prev_code_len, uint16_t* symbol_lists, + uint16_t* code_length_histo, int* next_symbol) { + *repeat = 0; + if (code_len != 0) { /* code_len == 1..15 */ + symbol_lists[next_symbol[code_len]] = (uint16_t)(*symbol); + next_symbol[code_len] = (int)(*symbol); + *prev_code_len = code_len; + *space -= 32768U >> code_len; + code_length_histo[code_len]++; + BROTLI_LOG(("[ReadHuffmanCode] code_length[%d] = %d\n", *symbol, code_len)); + } + (*symbol)++; +} + +/* Process repeated symbol code length. + A) Check if it is the extension of previous repeat sequence; if the decoded + value is not kCodeLengthRepeatCode, then it is a new symbol-skip + B) Update repeat variable + C) Check if operation is feasible (fits alphapet) + D) For each symbol do the same operations as in ProcessSingleCodeLength + + PRECONDITION: code_len == kCodeLengthRepeatCode or kCodeLengthRepeatCode + 1 + */ +static BROTLI_INLINE void ProcessRepeatedCodeLength(uint32_t code_len, + uint32_t repeat_delta, uint32_t alphabet_size, uint32_t* symbol, + uint32_t* repeat, uint32_t* space, uint32_t* prev_code_len, + uint32_t* repeat_code_len, uint16_t* symbol_lists, + uint16_t* code_length_histo, int* next_symbol) { + uint32_t old_repeat; + uint32_t new_len = 0; + if (code_len == kCodeLengthRepeatCode) { + new_len = *prev_code_len; + } + if (*repeat_code_len != new_len) { + *repeat = 0; + *repeat_code_len = new_len; + } + old_repeat = *repeat; + if (*repeat > 0) { + *repeat -= 2; + *repeat <<= code_len - 14U; + } + *repeat += repeat_delta + 3U; + repeat_delta = *repeat - old_repeat; + if (*symbol + repeat_delta > alphabet_size) { + BROTLI_DUMP(); + *symbol = alphabet_size; + *space = 0xFFFFF; + return; + } + BROTLI_LOG(("[ReadHuffmanCode] code_length[%d..%d] = %d\n", + *symbol, *symbol + repeat_delta - 1, *repeat_code_len)); + if (*repeat_code_len != 0) { + unsigned last = *symbol + repeat_delta; + int next = next_symbol[*repeat_code_len]; + do { + symbol_lists[next] = (uint16_t)*symbol; + next = (int)*symbol; + } while (++(*symbol) != last); + next_symbol[*repeat_code_len] = next; + *space -= repeat_delta << (15 - *repeat_code_len); + code_length_histo[*repeat_code_len] = + (uint16_t)(code_length_histo[*repeat_code_len] + repeat_delta); + } else { + *symbol += repeat_delta; + } +} + +/* Reads and decodes symbol codelengths. */ +static BrotliErrorCode ReadSymbolCodeLengths( + uint32_t alphabet_size, BrotliState* s) { + BrotliBitReader* br = &s->br; + uint32_t symbol = s->symbol; + uint32_t repeat = s->repeat; + uint32_t space = s->space; + uint32_t prev_code_len = s->prev_code_len; + uint32_t repeat_code_len = s->repeat_code_len; + uint16_t* symbol_lists = s->symbol_lists; + uint16_t* code_length_histo = s->code_length_histo; + int* next_symbol = s->next_symbol; + if (!BrotliWarmupBitReader(br)) { + return BROTLI_NEEDS_MORE_INPUT; + } + while (symbol < alphabet_size && space > 0) { + const HuffmanCode* p = s->table; + uint32_t code_len; + if (!BrotliCheckInputAmount(br, BROTLI_SHORT_FILL_BIT_WINDOW_READ)) { + s->symbol = symbol; + s->repeat = repeat; + s->prev_code_len = prev_code_len; + s->repeat_code_len = repeat_code_len; + s->space = space; + return BROTLI_NEEDS_MORE_INPUT; + } + BrotliFillBitWindow16(br); + p += BrotliGetBitsUnmasked(br) & + BitMask(BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH); + BrotliDropBits(br, p->bits); /* Use 1..5 bits */ + code_len = p->value; /* code_len == 0..17 */ + if (code_len < kCodeLengthRepeatCode) { + ProcessSingleCodeLength(code_len, &symbol, &repeat, &space, + &prev_code_len, symbol_lists, code_length_histo, next_symbol); + } else { /* code_len == 16..17, extra_bits == 2..3 */ + uint32_t repeat_delta = + (uint32_t)BrotliGetBitsUnmasked(br) & BitMask(code_len - 14U); + BrotliDropBits(br, code_len - 14U); + ProcessRepeatedCodeLength(code_len, repeat_delta, alphabet_size, + &symbol, &repeat, &space, &prev_code_len, &repeat_code_len, + symbol_lists, code_length_histo, next_symbol); + } + } + s->space = space; + return BROTLI_SUCCESS; +} + +static BrotliErrorCode SafeReadSymbolCodeLengths( + uint32_t alphabet_size, BrotliState* s) { + BrotliBitReader* br = &s->br; + while (s->symbol < alphabet_size && s->space > 0) { + const HuffmanCode* p = s->table; + uint32_t code_len; + uint32_t bits = 0; + uint32_t available_bits = BrotliGetAvailableBits(br); + if (available_bits != 0) { + bits = (uint32_t)BrotliGetBitsUnmasked(br); + } + p += bits & BitMask(BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH); + if (p->bits > available_bits) goto pullMoreInput; + code_len = p->value; /* code_len == 0..17 */ + if (code_len < kCodeLengthRepeatCode) { + BrotliDropBits(br, p->bits); + ProcessSingleCodeLength(code_len, &s->symbol, &s->repeat, &s->space, + &s->prev_code_len, s->symbol_lists, s->code_length_histo, + s->next_symbol); + } else { /* code_len == 16..17, extra_bits == 2..3 */ + uint32_t extra_bits = code_len - 14U; + uint32_t repeat_delta = (bits >> p->bits) & BitMask(extra_bits); + if (available_bits < p->bits + extra_bits) goto pullMoreInput; + BrotliDropBits(br, p->bits + extra_bits); + ProcessRepeatedCodeLength(code_len, repeat_delta, alphabet_size, + &s->symbol, &s->repeat, &s->space, &s->prev_code_len, + &s->repeat_code_len, s->symbol_lists, s->code_length_histo, + s->next_symbol); + } + continue; + +pullMoreInput: + if (!BrotliPullByte(br)) { + return BROTLI_NEEDS_MORE_INPUT; + } + } + return BROTLI_SUCCESS; +} + +/* Reads and decodes 15..18 codes using static prefix code. + Each code is 2..4 bits long. In total 30..72 bits are used. */ +static BrotliErrorCode ReadCodeLengthCodeLengths(BrotliState* s) { + BrotliBitReader* br = &s->br; + uint32_t num_codes = s->repeat; + unsigned space = s->space; + uint32_t i = s->sub_loop_counter; + for (; i < CODE_LENGTH_CODES; ++i) { + const uint8_t code_len_idx = kCodeLengthCodeOrder[i]; + uint32_t ix; + uint32_t v; + if (PREDICT_FALSE(!BrotliSafeGetBits(br, 4, &ix))) { + uint32_t available_bits = BrotliGetAvailableBits(br); + if (available_bits != 0) { + ix = BrotliGetBitsUnmasked(br) & 0xF; + } else { + ix = 0; + } + if (kCodeLengthPrefixLength[ix] > available_bits) { + s->sub_loop_counter = i; + s->repeat = num_codes; + s->space = space; + s->substate_huffman = BROTLI_STATE_HUFFMAN_COMPLEX; + return BROTLI_NEEDS_MORE_INPUT; + } + } + v = kCodeLengthPrefixValue[ix]; + BrotliDropBits(br, kCodeLengthPrefixLength[ix]); + s->code_length_code_lengths[code_len_idx] = (uint8_t)v; + BROTLI_LOG_ARRAY_INDEX(s->code_length_code_lengths, code_len_idx); + if (v != 0) { + space = space - (32U >> v); + ++num_codes; + ++s->code_length_histo[v]; + if (space - 1U >= 32U) { + /* space is 0 or wrapped around */ + break; + } + } + } + if (!(num_codes == 1 || space == 0)) { + return BROTLI_FAILURE(BROTLI_ERROR_FORMAT_CL_SPACE); + } + return BROTLI_SUCCESS; +} + +/* Decodes the Huffman tables. + There are 2 scenarios: + A) Huffman code contains only few symbols (1..4). Those symbols are read + directly; their code lengths are defined by the number of symbols. + For this scenario 4 - 45 bits will be read. + + B) 2-phase decoding: + B.1) Small Huffman table is decoded; it is specified with code lengths + encoded with predefined entropy code. 32 - 74 bits are used. + B.2) Decoded table is used to decode code lengths of symbols in resulting + Huffman table. In worst case 3520 bits are read. +*/ +static BrotliErrorCode ReadHuffmanCode(uint32_t alphabet_size, + HuffmanCode* table, + uint32_t* opt_table_size, + BrotliState* s) { + BrotliBitReader* br = &s->br; + /* Unnecessary masking, but might be good for safety. */ + alphabet_size &= 0x3ff; + /* State machine */ + switch (s->substate_huffman) { + case BROTLI_STATE_HUFFMAN_NONE: + if (!BrotliSafeReadBits(br, 2, &s->sub_loop_counter)) { + return BROTLI_NEEDS_MORE_INPUT; + } + BROTLI_LOG_UINT(s->sub_loop_counter); + /* The value is used as follows: + 1 for simple code; + 0 for no skipping, 2 skips 2 code lengths, 3 skips 3 code lengths */ + if (s->sub_loop_counter != 1) { + s->space = 32; + s->repeat = 0; /* num_codes */ + memset(&s->code_length_histo[0], 0, sizeof(s->code_length_histo[0]) * + (BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH + 1)); + memset(&s->code_length_code_lengths[0], 0, + sizeof(s->code_length_code_lengths)); + s->substate_huffman = BROTLI_STATE_HUFFMAN_COMPLEX; + goto Complex; + } + /* No break, transit to the next state. */ + + case BROTLI_STATE_HUFFMAN_SIMPLE_SIZE: + /* Read symbols, codes & code lengths directly. */ + if (!BrotliSafeReadBits(br, 2, &s->symbol)) { /* num_symbols */ + s->substate_huffman = BROTLI_STATE_HUFFMAN_SIMPLE_SIZE; + return BROTLI_NEEDS_MORE_INPUT; + } + s->sub_loop_counter = 0; + /* No break, transit to the next state. */ + case BROTLI_STATE_HUFFMAN_SIMPLE_READ: { + BrotliErrorCode result = ReadSimpleHuffmanSymbols(alphabet_size, s); + if (result != BROTLI_SUCCESS) { + return result; + } + /* No break, transit to the next state. */ + } + case BROTLI_STATE_HUFFMAN_SIMPLE_BUILD: { + uint32_t table_size; + if (s->symbol == 3) { + uint32_t bits; + if (!BrotliSafeReadBits(br, 1, &bits)) { + s->substate_huffman = BROTLI_STATE_HUFFMAN_SIMPLE_BUILD; + return BROTLI_NEEDS_MORE_INPUT; + } + s->symbol += bits; + } + BROTLI_LOG_UINT(s->symbol); + table_size = BrotliBuildSimpleHuffmanTable( + table, HUFFMAN_TABLE_BITS, s->symbols_lists_array, s->symbol); + if (opt_table_size) { + *opt_table_size = table_size; + } + s->substate_huffman = BROTLI_STATE_HUFFMAN_NONE; + return BROTLI_SUCCESS; + } + +Complex: /* Decode Huffman-coded code lengths. */ + case BROTLI_STATE_HUFFMAN_COMPLEX: { + uint32_t i; + BrotliErrorCode result = ReadCodeLengthCodeLengths(s); + if (result != BROTLI_SUCCESS) { + return result; + } + BrotliBuildCodeLengthsHuffmanTable(s->table, + s->code_length_code_lengths, + s->code_length_histo); + memset(&s->code_length_histo[0], 0, sizeof(s->code_length_histo)); + for (i = 0; i <= BROTLI_HUFFMAN_MAX_CODE_LENGTH; ++i) { + s->next_symbol[i] = (int)i - (BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1); + s->symbol_lists[(int)i - (BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1)] = 0xFFFF; + } + + s->symbol = 0; + s->prev_code_len = kDefaultCodeLength; + s->repeat = 0; + s->repeat_code_len = 0; + s->space = 32768; + s->substate_huffman = BROTLI_STATE_HUFFMAN_LENGTH_SYMBOLS; + /* No break, transit to the next state. */ + } + case BROTLI_STATE_HUFFMAN_LENGTH_SYMBOLS: { + uint32_t table_size; + BrotliErrorCode result = ReadSymbolCodeLengths(alphabet_size, s); + if (result == BROTLI_NEEDS_MORE_INPUT) { + result = SafeReadSymbolCodeLengths(alphabet_size, s); + } + if (result != BROTLI_SUCCESS) { + return result; + } + + if (s->space != 0) { + BROTLI_LOG(("[ReadHuffmanCode] space = %d\n", s->space)); + return BROTLI_FAILURE(BROTLI_ERROR_FORMAT_HUFFMAN_SPACE); + } + table_size = BrotliBuildHuffmanTable( + table, HUFFMAN_TABLE_BITS, s->symbol_lists, s->code_length_histo); + if (opt_table_size) { + *opt_table_size = table_size; + } + s->substate_huffman = BROTLI_STATE_HUFFMAN_NONE; + return BROTLI_SUCCESS; + } + + default: + return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE); + } +} + +/* Decodes a block length by reading 3..39 bits. */ +static BROTLI_INLINE uint32_t ReadBlockLength(const HuffmanCode* table, + BrotliBitReader* br) { + uint32_t code; + uint32_t nbits; + code = ReadSymbol(table, br); + nbits = kBlockLengthPrefixCode[code].nbits; /* nbits == 2..24 */ + return kBlockLengthPrefixCode[code].offset + BrotliReadBits(br, nbits); +} + +/* WARNING: if state is not BROTLI_STATE_READ_BLOCK_LENGTH_NONE, then + reading can't be continued with ReadBlockLength. */ +static BROTLI_INLINE int SafeReadBlockLength(BrotliState* s, + uint32_t* result, + const HuffmanCode* table, + BrotliBitReader* br) { + uint32_t index; + if (s->substate_read_block_length == BROTLI_STATE_READ_BLOCK_LENGTH_NONE) { + if (!SafeReadSymbol(table, br, &index)) { + return 0; + } + } else { + index = s->block_length_index; + } + { + uint32_t bits; + uint32_t nbits = kBlockLengthPrefixCode[index].nbits; /* nbits == 2..24 */ + if (!BrotliSafeReadBits(br, nbits, &bits)) { + s->block_length_index = index; + s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_SUFFIX; + return 0; + } + *result = kBlockLengthPrefixCode[index].offset + bits; + s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_NONE; + return 1; + } +} + +/* Transform: + 1) initialize list L with values 0, 1,... 255 + 2) For each input element X: + 2.1) let Y = L[X] + 2.2) remove X-th element from L + 2.3) prepend Y to L + 2.4) append Y to output + + In most cases max(Y) <= 7, so most of L remains intact. + To reduce the cost of initialization, we reuse L, remember the upper bound + of Y values, and reinitialize only first elements in L. + + Most of input values are 0 and 1. To reduce number of branches, we replace + inner for loop with do-while. + */ +static BROTLI_NOINLINE void InverseMoveToFrontTransform(uint8_t* v, + uint32_t v_len, BrotliState* state) { + /* Reinitialize elements that could have been changed. */ + uint32_t i = 4; + uint32_t upper_bound = state->mtf_upper_bound; + uint8_t* mtf = &state->mtf[4]; /* Make mtf[-1] addressable. */ + /* Load endian-aware constant. */ + const uint8_t b0123[4] = {0, 1, 2, 3}; + uint32_t pattern; + memcpy(&pattern, &b0123, 4); + + /* Initialize list using 4 consequent values pattern. */ + *(uint32_t*)mtf = pattern; + do { + pattern += 0x04040404; /* Advance all 4 values by 4. */ + *(uint32_t*)(mtf + i) = pattern; + i += 4; + } while (i <= upper_bound); + + /* Transform the input. */ + upper_bound = 0; + for (i = 0; i < v_len; ++i) { + int index = v[i]; + uint8_t value = mtf[index]; + upper_bound |= v[i]; + v[i] = value; + mtf[-1] = value; + do { + index--; + mtf[index + 1] = mtf[index]; + } while (index >= 0); + } + /* Remember amount of elements to be reinitialized. */ + state->mtf_upper_bound = upper_bound; +} + +/* Decodes a series of Huffman table using ReadHuffmanCode function. */ +static BrotliErrorCode HuffmanTreeGroupDecode(HuffmanTreeGroup* group, + BrotliState* s) { + if (s->substate_tree_group != BROTLI_STATE_TREE_GROUP_LOOP) { + s->next = group->codes; + s->htree_index = 0; + s->substate_tree_group = BROTLI_STATE_TREE_GROUP_LOOP; + } + while (s->htree_index < group->num_htrees) { + uint32_t table_size; + BrotliErrorCode result = + ReadHuffmanCode(group->alphabet_size, s->next, &table_size, s); + if (result != BROTLI_SUCCESS) return result; + group->htrees[s->htree_index] = s->next; + s->next += table_size; + ++s->htree_index; + } + s->substate_tree_group = BROTLI_STATE_TREE_GROUP_NONE; + return BROTLI_SUCCESS; +} + +/* Decodes a context map. + Decoding is done in 4 phases: + 1) Read auxiliary information (6..16 bits) and allocate memory. + In case of trivial context map, decoding is finished at this phase. + 2) Decode Huffman table using ReadHuffmanCode function. + This table will be used for reading context map items. + 3) Read context map items; "0" values could be run-length encoded. + 4) Optionally, apply InverseMoveToFront transform to the resulting map. + */ +static BrotliErrorCode DecodeContextMap(uint32_t context_map_size, + uint32_t* num_htrees, + uint8_t** context_map_arg, + BrotliState* s) { + BrotliBitReader* br = &s->br; + BrotliErrorCode result = BROTLI_SUCCESS; + + switch ((int)s->substate_context_map) { + case BROTLI_STATE_CONTEXT_MAP_NONE: + result = DecodeVarLenUint8(s, br, num_htrees); + if (result != BROTLI_SUCCESS) { + return result; + } + (*num_htrees)++; + s->context_index = 0; + BROTLI_LOG_UINT(context_map_size); + BROTLI_LOG_UINT(*num_htrees); + *context_map_arg = (uint8_t*)BROTLI_ALLOC(s, (size_t)context_map_size); + if (*context_map_arg == 0) { + return BROTLI_FAILURE(BROTLI_ERROR_ALLOC_CONTEXT_MAP); + } + if (*num_htrees <= 1) { + memset(*context_map_arg, 0, (size_t)context_map_size); + return BROTLI_SUCCESS; + } + s->substate_context_map = BROTLI_STATE_CONTEXT_MAP_READ_PREFIX; + /* No break, continue to next state. */ + case BROTLI_STATE_CONTEXT_MAP_READ_PREFIX: { + uint32_t bits; + /* In next stage ReadHuffmanCode uses at least 4 bits, so it is safe + to peek 4 bits ahead. */ + if (!BrotliSafeGetBits(br, 5, &bits)) { + return BROTLI_NEEDS_MORE_INPUT; + } + if ((bits & 1) != 0) { /* Use RLE for zeroes. */ + s->max_run_length_prefix = (bits >> 1) + 1; + BrotliDropBits(br, 5); + } else { + s->max_run_length_prefix = 0; + BrotliDropBits(br, 1); + } + BROTLI_LOG_UINT(s->max_run_length_prefix); + s->substate_context_map = BROTLI_STATE_CONTEXT_MAP_HUFFMAN; + /* No break, continue to next state. */ + } + case BROTLI_STATE_CONTEXT_MAP_HUFFMAN: + result = ReadHuffmanCode(*num_htrees + s->max_run_length_prefix, + s->context_map_table, NULL, s); + if (result != BROTLI_SUCCESS) return result; + s->code = 0xFFFF; + s->substate_context_map = BROTLI_STATE_CONTEXT_MAP_DECODE; + /* No break, continue to next state. */ + case BROTLI_STATE_CONTEXT_MAP_DECODE: { + uint32_t context_index = s->context_index; + uint32_t max_run_length_prefix = s->max_run_length_prefix; + uint8_t* context_map = *context_map_arg; + uint32_t code = s->code; + if (code != 0xFFFF) { + goto rleCode; + } + while (context_index < context_map_size) { + if (!SafeReadSymbol(s->context_map_table, br, &code)) { + s->code = 0xFFFF; + s->context_index = context_index; + return BROTLI_NEEDS_MORE_INPUT; + } + BROTLI_LOG_UINT(code); + + if (code == 0) { + context_map[context_index++] = 0; + continue; + } + if (code > max_run_length_prefix) { + context_map[context_index++] = + (uint8_t)(code - max_run_length_prefix); + continue; + } +rleCode: + { + uint32_t reps; + if (!BrotliSafeReadBits(br, code, &reps)) { + s->code = code; + s->context_index = context_index; + return BROTLI_NEEDS_MORE_INPUT; + } + reps += 1U << code; + BROTLI_LOG_UINT(reps); + if (context_index + reps > context_map_size) { + return BROTLI_FAILURE(BROTLI_ERROR_FORMAT_CONTEXT_MAP_REPEAT); + } + do { + context_map[context_index++] = 0; + } while (--reps); + } + } + /* No break, continue to next state. */ + } + case BROTLI_STATE_CONTEXT_MAP_TRANSFORM: { + uint32_t bits; + if (!BrotliSafeReadBits(br, 1, &bits)) { + s->substate_context_map = BROTLI_STATE_CONTEXT_MAP_TRANSFORM; + return BROTLI_NEEDS_MORE_INPUT; + } + if (bits != 0) { + InverseMoveToFrontTransform(*context_map_arg, context_map_size, s); + } + s->substate_context_map = BROTLI_STATE_CONTEXT_MAP_NONE; + return BROTLI_SUCCESS; + } + default: + return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE); + } +} + +/* Decodes a command or literal and updates block type ringbuffer. + Reads 3..54 bits. */ +static BROTLI_INLINE int DecodeBlockTypeAndLength(int safe, + BrotliState* s, int tree_type) { + uint32_t max_block_type = s->num_block_types[tree_type]; + const HuffmanCode* type_tree = &s->block_type_trees[ + tree_type * BROTLI_HUFFMAN_MAX_SIZE_258]; + const HuffmanCode* len_tree = &s->block_len_trees[ + tree_type * BROTLI_HUFFMAN_MAX_SIZE_26]; + BrotliBitReader* br = &s->br; + uint32_t* ringbuffer = &s->block_type_rb[tree_type * 2]; + uint32_t block_type; + + /* Read 0..15 + 3..39 bits */ + if (!safe) { + block_type = ReadSymbol(type_tree, br); + s->block_length[tree_type] = ReadBlockLength(len_tree, br); + } else { + BrotliBitReaderState memento; + BrotliBitReaderSaveState(br, &memento); + if (!SafeReadSymbol(type_tree, br, &block_type)) return 0; + if (!SafeReadBlockLength(s, &s->block_length[tree_type], len_tree, br)) { + s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_NONE; + BrotliBitReaderRestoreState(br, &memento); + return 0; + } + } + + if (block_type == 1) { + block_type = ringbuffer[1] + 1; + } else if (block_type == 0) { + block_type = ringbuffer[0]; + } else { + block_type -= 2; + } + if (block_type >= max_block_type) { + block_type -= max_block_type; + } + ringbuffer[0] = ringbuffer[1]; + ringbuffer[1] = block_type; + return 1; +} + +static BROTLI_INLINE void DetectTrivialLiteralBlockTypes(BrotliState* s) { + size_t i; + for (i = 0; i < 8; ++i) s->trivial_literal_contexts[i] = 0; + for (i = 0; i < s->num_block_types[0]; i++) { + size_t offset = i << kLiteralContextBits; + size_t error = 0; + size_t sample = s->context_map[offset]; + size_t j; + for (j = 0; j < (1u << kLiteralContextBits);) { + BROTLI_REPEAT(4, error |= s->context_map[offset + j++] ^ sample;) + } + if (error == 0) { + s->trivial_literal_contexts[i >> 5] |= 1u << (i & 31); + } + } +} + +static BROTLI_INLINE void PrepareLiteralDecoding(BrotliState* s) { + uint8_t context_mode; + size_t trivial; + uint32_t block_type = s->block_type_rb[1]; + uint32_t context_offset = block_type << kLiteralContextBits; + s->context_map_slice = s->context_map + context_offset; + trivial = s->trivial_literal_contexts[block_type >> 5]; + s->trivial_literal_context = (trivial >> (block_type & 31)) & 1; + s->literal_htree = s->literal_hgroup.htrees[s->context_map_slice[0]]; + context_mode = s->context_modes[block_type]; + s->context_lookup1 = &kContextLookup[kContextLookupOffsets[context_mode]]; + s->context_lookup2 = &kContextLookup[kContextLookupOffsets[context_mode + 1]]; +} + +/* Decodes the block type and updates the state for literal context. + Reads 3..54 bits. */ +static BROTLI_INLINE int DecodeLiteralBlockSwitchInternal(int safe, + BrotliState* s) { + if (!DecodeBlockTypeAndLength(safe, s, 0)) { + return 0; + } + PrepareLiteralDecoding(s); + return 1; +} + +static void BROTLI_NOINLINE DecodeLiteralBlockSwitch(BrotliState* s) { + DecodeLiteralBlockSwitchInternal(0, s); +} + +static int BROTLI_NOINLINE SafeDecodeLiteralBlockSwitch(BrotliState* s) { + return DecodeLiteralBlockSwitchInternal(1, s); +} + +/* Block switch for insert/copy length. + Reads 3..54 bits. */ +static BROTLI_INLINE int DecodeCommandBlockSwitchInternal(int safe, + BrotliState* s) { + if (!DecodeBlockTypeAndLength(safe, s, 1)) { + return 0; + } + s->htree_command = s->insert_copy_hgroup.htrees[s->block_type_rb[3]]; + return 1; +} + +static void BROTLI_NOINLINE DecodeCommandBlockSwitch(BrotliState* s) { + DecodeCommandBlockSwitchInternal(0, s); +} +static int BROTLI_NOINLINE SafeDecodeCommandBlockSwitch(BrotliState* s) { + return DecodeCommandBlockSwitchInternal(1, s); +} + +/* Block switch for distance codes. + Reads 3..54 bits. */ +static BROTLI_INLINE int DecodeDistanceBlockSwitchInternal(int safe, + BrotliState* s) { + if (!DecodeBlockTypeAndLength(safe, s, 2)) { + return 0; + } + s->dist_context_map_slice = + s->dist_context_map + (s->block_type_rb[5] << kDistanceContextBits); + s->dist_htree_index = s->dist_context_map_slice[s->distance_context]; + return 1; +} + +static void BROTLI_NOINLINE DecodeDistanceBlockSwitch(BrotliState* s) { + DecodeDistanceBlockSwitchInternal(0, s); +} + +static int BROTLI_NOINLINE SafeDecodeDistanceBlockSwitch(BrotliState* s) { + return DecodeDistanceBlockSwitchInternal(1, s); +} + +static BrotliErrorCode BROTLI_NOINLINE WriteRingBuffer(size_t* available_out, + uint8_t** next_out, size_t* total_out, BrotliState* s) { + size_t pos = (s->pos > s->ringbuffer_size) ? (size_t)s->ringbuffer_size + : (size_t)(s->pos); + uint8_t* start = + s->ringbuffer + (s->partial_pos_out & (size_t)s->ringbuffer_mask); + size_t partial_pos_rb = (s->rb_roundtrips * (size_t)s->ringbuffer_size) + pos; + size_t to_write = (partial_pos_rb - s->partial_pos_out); + size_t num_written = *available_out; + if (num_written > to_write) { + num_written = to_write; + } + if (s->meta_block_remaining_len < 0) { + return BROTLI_FAILURE(BROTLI_ERROR_FORMAT_BLOCK_LENGTH_1); + } + memcpy(*next_out, start, num_written); + *next_out += num_written; + *available_out -= num_written; + BROTLI_LOG_UINT(to_write); + BROTLI_LOG_UINT(num_written); + s->partial_pos_out += num_written; + if (total_out) *total_out = s->partial_pos_out; + if (num_written < to_write) { + return BROTLI_NEEDS_MORE_OUTPUT; + } + + if (s->pos >= s->ringbuffer_size) { + s->pos -= s->ringbuffer_size; + s->rb_roundtrips++; + } + return BROTLI_SUCCESS; +} + +/* Allocates ringbuffer. + + s->ringbuffer_size MUST be updated by BrotliCalculateRingBufferSize before + this function is called. + + Last two bytes of ringbuffer are initialized to 0, so context calculation + could be done uniformly for the first two and all other positions. + + Custom dictionary, if any, is copied to the end of ringbuffer. +*/ +static int BROTLI_NOINLINE BrotliAllocateRingBuffer(BrotliState* s) { + /* We need the slack region for the following reasons: + - doing up to two 16-byte copies for fast backward copying + - inserting transformed dictionary word (5 prefix + 24 base + 8 suffix) */ + static const int kRingBufferWriteAheadSlack = 42; + s->ringbuffer = (uint8_t*)BROTLI_ALLOC(s, (size_t)(s->ringbuffer_size + + kRingBufferWriteAheadSlack)); + if (s->ringbuffer == 0) { + return 0; + } + + s->ringbuffer_end = s->ringbuffer + s->ringbuffer_size; + + s->ringbuffer[s->ringbuffer_size - 2] = 0; + s->ringbuffer[s->ringbuffer_size - 1] = 0; + + if (s->custom_dict) { + memcpy(&s->ringbuffer[(-s->custom_dict_size) & s->ringbuffer_mask], + s->custom_dict, (size_t)s->custom_dict_size); + } + + return 1; +} + +static BrotliErrorCode BROTLI_NOINLINE CopyUncompressedBlockToOutput( + size_t* available_out, uint8_t** next_out, size_t* total_out, + BrotliState* s) { + /* TODO: avoid allocation for single uncompressed block. */ + if (!s->ringbuffer && !BrotliAllocateRingBuffer(s)) { + return BROTLI_FAILURE(BROTLI_ERROR_ALLOC_RING_BUFFER_1); + } + + /* State machine */ + for (;;) { + switch (s->substate_uncompressed) { + case BROTLI_STATE_UNCOMPRESSED_NONE: { + int nbytes = (int)BrotliGetRemainingBytes(&s->br); + if (nbytes > s->meta_block_remaining_len) { + nbytes = s->meta_block_remaining_len; + } + if (s->pos + nbytes > s->ringbuffer_size) { + nbytes = s->ringbuffer_size - s->pos; + } + /* Copy remaining bytes from s->br.buf_ to ringbuffer. */ + BrotliCopyBytes(&s->ringbuffer[s->pos], &s->br, (size_t)nbytes); + s->pos += nbytes; + s->meta_block_remaining_len -= nbytes; + if (s->pos < s->ringbuffer_size) { + if (s->meta_block_remaining_len == 0) { + return BROTLI_SUCCESS; + } + return BROTLI_NEEDS_MORE_INPUT; + } + s->substate_uncompressed = BROTLI_STATE_UNCOMPRESSED_WRITE; + /* No break, continue to next state */ + } + case BROTLI_STATE_UNCOMPRESSED_WRITE: { + BrotliErrorCode result = + WriteRingBuffer(available_out, next_out, total_out, s); + if (result != BROTLI_SUCCESS) { + return result; + } + s->max_distance = s->max_backward_distance; + s->substate_uncompressed = BROTLI_STATE_UNCOMPRESSED_NONE; + break; + } + } + } + BROTLI_DCHECK(0); /* Unreachable */ +} + +int BrotliDecompressedSize(size_t encoded_size, + const uint8_t* encoded_buffer, + size_t* decoded_size) { + BrotliState s; + int next_block_header; + BrotliStateInit(&s); + s.br.next_in = encoded_buffer; + s.br.avail_in = encoded_size; + if (!BrotliWarmupBitReader(&s.br)) { + return 0; + } + DecodeWindowBits(&s.br); + if (DecodeMetaBlockLength(&s, &s.br) != BROTLI_SUCCESS) { + return 0; + } + *decoded_size = (size_t)s.meta_block_remaining_len; + if (s.is_last_metablock) { + return 1; + } + if (!s.is_uncompressed || !BrotliJumpToByteBoundary(&s.br)) { + return 0; + } + next_block_header = BrotliPeekByte(&s.br, (size_t)s.meta_block_remaining_len); + return (next_block_header != -1) && ((next_block_header & 3) == 3); +} + +/* Calculates the smallest feasible ring buffer. + + If we know the data size is small, do not allocate more ringbuffer + size than needed to reduce memory usage. + + When this method is called, metablock size and flags MUST be decoded. +*/ +static void BROTLI_NOINLINE BrotliCalculateRingBufferSize(BrotliState* s, + BrotliBitReader* br) { + int is_last = s->is_last_metablock; + int window_size = 1 << s->window_bits; + s->ringbuffer_size = window_size; + + if (s->is_uncompressed) { + int next_block_header = + BrotliPeekByte(br, (size_t)s->meta_block_remaining_len); + if (next_block_header != -1) { /* Peek succeeded */ + if ((next_block_header & 3) == 3) { /* ISLAST and ISEMPTY */ + is_last = 1; + } + } + } + + /* We need at least 2 bytes of ring buffer size to get the last two + bytes for context from there */ + if (is_last) { + int min_size_x2 = (s->meta_block_remaining_len + s->custom_dict_size) * 2; + while (s->ringbuffer_size >= min_size_x2 && s->ringbuffer_size > 32) { + s->ringbuffer_size >>= 1; + } + } + + s->ringbuffer_mask = s->ringbuffer_size - 1; +} + +/* Reads 1..256 2-bit context modes. */ +static BrotliErrorCode ReadContextModes(BrotliState* s) { + BrotliBitReader* br = &s->br; + int i = s->loop_counter; + + while (i < (int)s->num_block_types[0]) { + uint32_t bits; + if (!BrotliSafeReadBits(br, 2, &bits)) { + s->loop_counter = i; + return BROTLI_NEEDS_MORE_INPUT; + } + s->context_modes[i] = (uint8_t)(bits << 1); + BROTLI_LOG_ARRAY_INDEX(s->context_modes, i); + i++; + } + return BROTLI_SUCCESS; +} + +static BROTLI_INLINE void TakeDistanceFromRingBuffer(BrotliState* s) { + if (s->distance_code == 0) { + --s->dist_rb_idx; + s->distance_code = s->dist_rb[s->dist_rb_idx & 3]; + } else { + int distance_code = s->distance_code << 1; + /* kDistanceShortCodeIndexOffset has 2-bit values from LSB: */ + /* 3, 2, 1, 0, 3, 3, 3, 3, 3, 3, 2, 2, 2, 2, 2, 2 */ + const uint32_t kDistanceShortCodeIndexOffset = 0xaaafff1b; + /* kDistanceShortCodeValueOffset has 2-bit values from LSB: */ + /*-0, 0,-0, 0,-1, 1,-2, 2,-3, 3,-1, 1,-2, 2,-3, 3 */ + const uint32_t kDistanceShortCodeValueOffset = 0xfa5fa500; + int v = (s->dist_rb_idx + + (int)(kDistanceShortCodeIndexOffset >> distance_code)) & 0x3; + s->distance_code = s->dist_rb[v]; + v = (int)(kDistanceShortCodeValueOffset >> distance_code) & 0x3; + if ((distance_code & 0x3) != 0) { + s->distance_code += v; + } else { + s->distance_code -= v; + if (s->distance_code <= 0) { + /* A huge distance will cause a BROTLI_FAILURE() soon. */ + /* This is a little faster than failing here. */ + s->distance_code = 0x0fffffff; + } + } + } +} + +static BROTLI_INLINE int SafeReadBits( + BrotliBitReader* const br, uint32_t n_bits, uint32_t* val) { + if (n_bits != 0) { + return BrotliSafeReadBits(br, n_bits, val); + } else { + *val = 0; + return 1; + } +} + +/* Precondition: s->distance_code < 0 */ +static BROTLI_INLINE int ReadDistanceInternal(int safe, + BrotliState* s, BrotliBitReader* br) { + int distval; + BrotliBitReaderState memento; + HuffmanCode* distance_tree = s->distance_hgroup.htrees[s->dist_htree_index]; + if (!safe) { + s->distance_code = (int)ReadSymbol(distance_tree, br); + } else { + uint32_t code; + BrotliBitReaderSaveState(br, &memento); + if (!SafeReadSymbol(distance_tree, br, &code)) { + return 0; + } + s->distance_code = (int)code; + } + /* Convert the distance code to the actual distance by possibly */ + /* looking up past distances from the s->ringbuffer. */ + if ((s->distance_code & ~0xf) == 0) { + TakeDistanceFromRingBuffer(s); + --s->block_length[2]; + return 1; + } + distval = s->distance_code - (int)s->num_direct_distance_codes; + if (distval >= 0) { + uint32_t nbits; + int postfix; + int offset; + if (!safe && (s->distance_postfix_bits == 0)) { + nbits = ((uint32_t)distval >> 1) + 1; + offset = ((2 + (distval & 1)) << nbits) - 4; + s->distance_code = (int)s->num_direct_distance_codes + offset + + (int)BrotliReadBits(br, nbits); + } else { + /* This branch also works well when s->distance_postfix_bits == 0 */ + uint32_t bits; + postfix = distval & s->distance_postfix_mask; + distval >>= s->distance_postfix_bits; + nbits = ((uint32_t)distval >> 1) + 1; + if (safe) { + if (!SafeReadBits(br, nbits, &bits)) { + s->distance_code = -1; /* Restore precondition. */ + BrotliBitReaderRestoreState(br, &memento); + return 0; + } + } else { + bits = BrotliReadBits(br, nbits); + } + offset = ((2 + (distval & 1)) << nbits) - 4; + s->distance_code = (int)s->num_direct_distance_codes + + ((offset + (int)bits) << s->distance_postfix_bits) + postfix; + } + } + s->distance_code = s->distance_code - NUM_DISTANCE_SHORT_CODES + 1; + --s->block_length[2]; + return 1; +} + +static BROTLI_INLINE void ReadDistance(BrotliState* s, BrotliBitReader* br) { + ReadDistanceInternal(0, s, br); +} + +static BROTLI_INLINE int SafeReadDistance(BrotliState* s, BrotliBitReader* br) { + return ReadDistanceInternal(1, s, br); +} + +static BROTLI_INLINE int ReadCommandInternal(int safe, + BrotliState* s, BrotliBitReader* br, int* insert_length) { + uint32_t cmd_code; + uint32_t insert_len_extra = 0; + uint32_t copy_length; + CmdLutElement v; + BrotliBitReaderState memento; + if (!safe) { + cmd_code = ReadSymbol(s->htree_command, br); + } else { + BrotliBitReaderSaveState(br, &memento); + if (!SafeReadSymbol(s->htree_command, br, &cmd_code)) { + return 0; + } + } + v = kCmdLut[cmd_code]; + s->distance_code = v.distance_code; + s->distance_context = v.context; + s->dist_htree_index = s->dist_context_map_slice[s->distance_context]; + *insert_length = v.insert_len_offset; + if (!safe) { + if (PREDICT_FALSE(v.insert_len_extra_bits != 0)) { + insert_len_extra = BrotliReadBits(br, v.insert_len_extra_bits); + } + copy_length = BrotliReadBits(br, v.copy_len_extra_bits); + } else { + if (!SafeReadBits(br, v.insert_len_extra_bits, &insert_len_extra) || + !SafeReadBits(br, v.copy_len_extra_bits, ©_length)) { + BrotliBitReaderRestoreState(br, &memento); + return 0; + } + } + s->copy_length = (int)copy_length + v.copy_len_offset; + --s->block_length[1]; + *insert_length += (int)insert_len_extra; + return 1; +} + +static BROTLI_INLINE void ReadCommand(BrotliState* s, BrotliBitReader* br, + int* insert_length) { + ReadCommandInternal(0, s, br, insert_length); +} + +static BROTLI_INLINE int SafeReadCommand(BrotliState* s, BrotliBitReader* br, + int* insert_length) { + return ReadCommandInternal(1, s, br, insert_length); +} + +static BROTLI_INLINE int CheckInputAmount(int safe, + BrotliBitReader* const br, size_t num) { + if (safe) { + return 1; + } + return BrotliCheckInputAmount(br, num); +} + +#define BROTLI_SAFE(METHOD) \ + { \ + if (safe) { \ + if (!Safe##METHOD) { \ + result = BROTLI_NEEDS_MORE_INPUT; \ + goto saveStateAndReturn; \ + } \ + } else { \ + METHOD; \ + } \ + } + +static BROTLI_INLINE BrotliErrorCode ProcessCommandsInternal(int safe, + BrotliState* s) { + int pos = s->pos; + int i = s->loop_counter; + BrotliErrorCode result = BROTLI_SUCCESS; + BrotliBitReader* br = &s->br; + + if (!CheckInputAmount(safe, br, 28)) { + result = BROTLI_NEEDS_MORE_INPUT; + goto saveStateAndReturn; + } + if (!safe) { + BROTLI_UNUSED(BrotliWarmupBitReader(br)); + } + + /* Jump into state machine. */ + if (s->state == BROTLI_STATE_COMMAND_BEGIN) { + goto CommandBegin; + } else if (s->state == BROTLI_STATE_COMMAND_INNER) { + goto CommandInner; + } else if (s->state == BROTLI_STATE_COMMAND_POST_DECODE_LITERALS) { + goto CommandPostDecodeLiterals; + } else if (s->state == BROTLI_STATE_COMMAND_POST_WRAP_COPY) { + goto CommandPostWrapCopy; + } else { + return BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE); + } + +CommandBegin: + if (safe) { + s->state = BROTLI_STATE_COMMAND_BEGIN; + } + if (!CheckInputAmount(safe, br, 28)) { /* 156 bits + 7 bytes */ + s->state = BROTLI_STATE_COMMAND_BEGIN; + result = BROTLI_NEEDS_MORE_INPUT; + goto saveStateAndReturn; + } + if (PREDICT_FALSE(s->block_length[1] == 0)) { + BROTLI_SAFE(DecodeCommandBlockSwitch(s)); + goto CommandBegin; + } + /* Read the insert/copy length in the command */ + BROTLI_SAFE(ReadCommand(s, br, &i)); + BROTLI_LOG(("[ProcessCommandsInternal] pos = %d insert = %d copy = %d\n", + pos, i, s->copy_length)); + if (i == 0) { + goto CommandPostDecodeLiterals; + } + s->meta_block_remaining_len -= i; + +CommandInner: + if (safe) { + s->state = BROTLI_STATE_COMMAND_INNER; + } + /* Read the literals in the command */ + if (s->trivial_literal_context) { + uint32_t bits; + uint32_t value; + PreloadSymbol(safe, s->literal_htree, br, &bits, &value); + do { + if (!CheckInputAmount(safe, br, 28)) { /* 162 bits + 7 bytes */ + s->state = BROTLI_STATE_COMMAND_INNER; + result = BROTLI_NEEDS_MORE_INPUT; + goto saveStateAndReturn; + } + if (PREDICT_FALSE(s->block_length[0] == 0)) { + BROTLI_SAFE(DecodeLiteralBlockSwitch(s)); + PreloadSymbol(safe, s->literal_htree, br, &bits, &value); + if (!s->trivial_literal_context) goto CommandInner; + } + if (!safe) { + s->ringbuffer[pos] = + (uint8_t)ReadPreloadedSymbol(s->literal_htree, br, &bits, &value); + } else { + uint32_t literal; + if (!SafeReadSymbol(s->literal_htree, br, &literal)) { + result = BROTLI_NEEDS_MORE_INPUT; + goto saveStateAndReturn; + } + s->ringbuffer[pos] = (uint8_t)literal; + } + --s->block_length[0]; + BROTLI_LOG_ARRAY_INDEX(s->ringbuffer, pos); + ++pos; + if (PREDICT_FALSE(pos == s->ringbuffer_size)) { + s->state = BROTLI_STATE_COMMAND_INNER_WRITE; + --i; + goto saveStateAndReturn; + } + } while (--i != 0); + } else { + uint8_t p1 = s->ringbuffer[(pos - 1) & s->ringbuffer_mask]; + uint8_t p2 = s->ringbuffer[(pos - 2) & s->ringbuffer_mask]; + do { + const HuffmanCode* hc; + uint8_t context; + if (!CheckInputAmount(safe, br, 28)) { /* 162 bits + 7 bytes */ + s->state = BROTLI_STATE_COMMAND_INNER; + result = BROTLI_NEEDS_MORE_INPUT; + goto saveStateAndReturn; + } + if (PREDICT_FALSE(s->block_length[0] == 0)) { + BROTLI_SAFE(DecodeLiteralBlockSwitch(s)); + if (s->trivial_literal_context) goto CommandInner; + } + context = s->context_lookup1[p1] | s->context_lookup2[p2]; + BROTLI_LOG_UINT(context); + hc = s->literal_hgroup.htrees[s->context_map_slice[context]]; + p2 = p1; + if (!safe) { + p1 = (uint8_t)ReadSymbol(hc, br); + } else { + uint32_t literal; + if (!SafeReadSymbol(hc, br, &literal)) { + result = BROTLI_NEEDS_MORE_INPUT; + goto saveStateAndReturn; + } + p1 = (uint8_t)literal; + } + s->ringbuffer[pos] = p1; + --s->block_length[0]; + BROTLI_LOG_UINT(s->context_map_slice[context]); + BROTLI_LOG_ARRAY_INDEX(s->ringbuffer, pos & s->ringbuffer_mask); + ++pos; + if (PREDICT_FALSE(pos == s->ringbuffer_size)) { + s->state = BROTLI_STATE_COMMAND_INNER_WRITE; + --i; + goto saveStateAndReturn; + } + } while (--i != 0); + } + BROTLI_LOG_UINT(s->meta_block_remaining_len); + if (PREDICT_FALSE(s->meta_block_remaining_len <= 0)) { + s->state = BROTLI_STATE_METABLOCK_DONE; + goto saveStateAndReturn; + } + +CommandPostDecodeLiterals: + if (safe) { + s->state = BROTLI_STATE_COMMAND_POST_DECODE_LITERALS; + } + if (s->distance_code >= 0) { + --s->dist_rb_idx; + s->distance_code = s->dist_rb[s->dist_rb_idx & 3]; + goto postReadDistance; /* We already have the implicit distance */ + } + /* Read distance code in the command, unless it was implicitly zero. */ + if (PREDICT_FALSE(s->block_length[2] == 0)) { + BROTLI_SAFE(DecodeDistanceBlockSwitch(s)); + } + BROTLI_SAFE(ReadDistance(s, br)); +postReadDistance: + BROTLI_LOG(("[ProcessCommandsInternal] pos = %d distance = %d\n", + pos, s->distance_code)); + if (s->max_distance != s->max_backward_distance) { + if (pos < s->max_backward_distance_minus_custom_dict_size) { + s->max_distance = pos + s->custom_dict_size; + } else { + s->max_distance = s->max_backward_distance; + } + } + i = s->copy_length; + /* Apply copy of LZ77 back-reference, or static dictionary reference if + the distance is larger than the max LZ77 distance */ + if (s->distance_code > s->max_distance) { + if (i >= kBrotliMinDictionaryWordLength && + i <= kBrotliMaxDictionaryWordLength) { + int offset = (int)kBrotliDictionaryOffsetsByLength[i]; + int word_id = s->distance_code - s->max_distance - 1; + uint32_t shift = kBrotliDictionarySizeBitsByLength[i]; + int mask = (int)BitMask(shift); + int word_idx = word_id & mask; + int transform_idx = word_id >> shift; + offset += word_idx * i; + if (transform_idx < kNumTransforms) { + const uint8_t* word = &kBrotliDictionary[offset]; + int len = i; + if (transform_idx == 0) { + memcpy(&s->ringbuffer[pos], word, (size_t)len); + } else { + len = TransformDictionaryWord( + &s->ringbuffer[pos], word, len, transform_idx); + } + pos += len; + s->meta_block_remaining_len -= len; + if (pos >= s->ringbuffer_size) { + /*s->partial_pos_rb += (size_t)s->ringbuffer_size;*/ + s->state = BROTLI_STATE_COMMAND_POST_WRITE_1; + goto saveStateAndReturn; + } + } else { + BROTLI_LOG(("Invalid backward reference. pos: %d distance: %d " + "len: %d bytes left: %d\n", + pos, s->distance_code, i, s->meta_block_remaining_len)); + return BROTLI_FAILURE(BROTLI_ERROR_FORMAT_TRANSFORM); + } + } else { + BROTLI_LOG(("Invalid backward reference. pos: %d distance: %d " + "len: %d bytes left: %d\n", + pos, s->distance_code, i, s->meta_block_remaining_len)); + return BROTLI_FAILURE(BROTLI_ERROR_FORMAT_DICTIONARY); + } + } else { + int src_start = (pos - s->distance_code) & s->ringbuffer_mask; + uint8_t* copy_dst = &s->ringbuffer[pos]; + uint8_t* copy_src = &s->ringbuffer[src_start]; + int dst_end = pos + i; + int src_end = src_start + i; + /* update the recent distances cache */ + s->dist_rb[s->dist_rb_idx & 3] = s->distance_code; + ++s->dist_rb_idx; + s->meta_block_remaining_len -= i; + /* There are 32+ bytes of slack in the ringbuffer allocation. + Also, we have 16 short codes, that make these 16 bytes irrelevant + in the ringbuffer. Let's copy over them as a first guess. + */ + memmove16(copy_dst, copy_src); + if (src_end > pos && dst_end > src_start) { + /* Regions intersect. */ + goto CommandPostWrapCopy; + } + if (dst_end >= s->ringbuffer_size || src_end >= s->ringbuffer_size) { + /* At least one region wraps. */ + goto CommandPostWrapCopy; + } + pos += i; + if (i > 16) { + if (i > 32) { + memcpy(copy_dst + 16, copy_src + 16, (size_t)(i - 16)); + } else { + /* This branch covers about 45% cases. + Fixed size short copy allows more compiler optimizations. */ + memmove16(copy_dst + 16, copy_src + 16); + } + } + } + BROTLI_LOG_UINT(s->meta_block_remaining_len); + if (s->meta_block_remaining_len <= 0) { + /* Next metablock, if any */ + s->state = BROTLI_STATE_METABLOCK_DONE; + goto saveStateAndReturn; + } else { + goto CommandBegin; + } +CommandPostWrapCopy: + { + int wrap_guard = s->ringbuffer_size - pos; + while (--i >= 0) { + s->ringbuffer[pos] = + s->ringbuffer[(pos - s->distance_code) & s->ringbuffer_mask]; + ++pos; + if (PREDICT_FALSE(--wrap_guard == 0)) { + s->state = BROTLI_STATE_COMMAND_POST_WRITE_2; + goto saveStateAndReturn; + } + } + } + if (s->meta_block_remaining_len <= 0) { + /* Next metablock, if any */ + s->state = BROTLI_STATE_METABLOCK_DONE; + goto saveStateAndReturn; + } else { + goto CommandBegin; + } + +saveStateAndReturn: + s->pos = pos; + s->loop_counter = i; + return result; +} + +#undef BROTLI_SAFE + +static BROTLI_NOINLINE BrotliErrorCode ProcessCommands(BrotliState* s) { + return ProcessCommandsInternal(0, s); +} + +static BROTLI_NOINLINE BrotliErrorCode SafeProcessCommands(BrotliState* s) { + return ProcessCommandsInternal(1, s); +} + +BrotliResult BrotliDecompressBuffer(size_t encoded_size, + const uint8_t* encoded_buffer, + size_t* decoded_size, + uint8_t* decoded_buffer) { + BrotliState s; + BrotliResult result; + size_t total_out = 0; + size_t available_in = encoded_size; + const uint8_t* next_in = encoded_buffer; + size_t available_out = *decoded_size; + uint8_t* next_out = decoded_buffer; + BrotliStateInit(&s); + result = BrotliDecompressStream(&available_in, &next_in, &available_out, + &next_out, &total_out, &s); + *decoded_size = total_out; + BrotliStateCleanup(&s); + if (result != BROTLI_RESULT_SUCCESS) { + result = BROTLI_RESULT_ERROR; + } + return result; +} + +/* Invariant: input stream is never overconsumed: + * invalid input implies that the whole stream is invalid -> any amount of + input could be read and discarded + * when result is "needs more input", then at leat one more byte is REQUIRED + to complete decoding; all input data MUST be consumed by decoder, so + client could swap the input buffer + * when result is "needs more output" decoder MUST ensure that it doesn't + hold more than 7 bits in bit reader; this saves client from swapping input + buffer ahead of time + * when result is "success" decoder MUST return all unused data back to input + buffer; this is possible because the invariant is hold on enter +*/ +BrotliResult BrotliDecompressStream(size_t* available_in, + const uint8_t** next_in, size_t* available_out, uint8_t** next_out, + size_t* total_out, BrotliState* s) { + BrotliErrorCode result = BROTLI_SUCCESS; + BrotliBitReader* br = &s->br; + if (s->buffer_length == 0) { /* Just connect bit reader to input stream. */ + br->avail_in = *available_in; + br->next_in = *next_in; + } else { + /* At least one byte of input is required. More than one byte of input may + be required to complete the transaction -> reading more data must be + done in a loop -> do it in a main loop. */ + result = BROTLI_NEEDS_MORE_INPUT; + br->next_in = &s->buffer.u8[0]; + } + /* State machine */ + for (;;) { + if (result != BROTLI_SUCCESS) { /* Error | needs more input/output */ + if (result == BROTLI_NEEDS_MORE_INPUT) { + if (s->ringbuffer != 0) { /* Proactively push output. */ + WriteRingBuffer(available_out, next_out, total_out, s); + } + if (s->buffer_length != 0) { /* Used with internal buffer. */ + if (br->avail_in == 0) { /* Successfully finished read transaction. */ + /* Accamulator contains less than 8 bits, because internal buffer + is expanded byte-by-byte until it is enough to complete read. */ + s->buffer_length = 0; + /* Switch to input stream and restart. */ + result = BROTLI_SUCCESS; + br->avail_in = *available_in; + br->next_in = *next_in; + continue; + } else if (*available_in != 0) { + /* Not enough data in buffer, but can take one more byte from + input stream. */ + result = BROTLI_SUCCESS; + s->buffer.u8[s->buffer_length] = **next_in; + s->buffer_length++; + br->avail_in = s->buffer_length; + (*next_in)++; + (*available_in)--; + /* Retry with more data in buffer. */ + continue; + } + /* Can't finish reading and no more input.*/ + break; + } else { /* Input stream doesn't contain enough input. */ + /* Copy tail to internal buffer and return. */ + *next_in = br->next_in; + *available_in = br->avail_in; + while (*available_in) { + s->buffer.u8[s->buffer_length] = **next_in; + s->buffer_length++; + (*next_in)++; + (*available_in)--; + } + break; + } + /* Unreachable. */ + } + + /* Fail or needs more output. */ + + if (s->buffer_length != 0) { + /* Just consumed the buffered input and produced some output. Otherwise + it would result in "needs more input". Reset internal buffer.*/ + s->buffer_length = 0; + } else { + /* Using input stream in last iteration. When decoder switches to input + stream it has less than 8 bits in accamulator, so it is safe to + return unused accamulator bits there. */ + BrotliBitReaderUnload(br); + *available_in = br->avail_in; + *next_in = br->next_in; + } + break; + } + switch (s->state) { + case BROTLI_STATE_UNINITED: + /* Prepare to the first read. */ + if (!BrotliWarmupBitReader(br)) { + result = BROTLI_NEEDS_MORE_INPUT; + break; + } + /* Decode window size. */ + s->window_bits = DecodeWindowBits(br); /* Reads 1..7 bits. */ + BROTLI_LOG_UINT(s->window_bits); + if (s->window_bits == 9) { + /* Value 9 is reserved for future use. */ + result = BROTLI_FAILURE(BROTLI_ERROR_FORMAT_WINDOW_BITS); + break; + } + /* Maximum distance, see section 9.1. of the spec. */ + s->max_backward_distance = (1 << s->window_bits) - 16; + /* Limit custom dictionary size. */ + if (s->custom_dict_size >= s->max_backward_distance) { + s->custom_dict += s->custom_dict_size - s->max_backward_distance; + s->custom_dict_size = s->max_backward_distance; + } + s->max_backward_distance_minus_custom_dict_size = + s->max_backward_distance - s->custom_dict_size; + + /* Allocate memory for both block_type_trees and block_len_trees. */ + s->block_type_trees = (HuffmanCode*)BROTLI_ALLOC(s, + sizeof(HuffmanCode) * 3 * + (BROTLI_HUFFMAN_MAX_SIZE_258 + BROTLI_HUFFMAN_MAX_SIZE_26)); + if (s->block_type_trees == 0) { + result = BROTLI_FAILURE(BROTLI_ERROR_ALLOC_BLOCK_TYPE_TREES); + break; + } + s->block_len_trees = + s->block_type_trees + 3 * BROTLI_HUFFMAN_MAX_SIZE_258; + + s->state = BROTLI_STATE_METABLOCK_BEGIN; + /* No break, continue to next state */ + case BROTLI_STATE_METABLOCK_BEGIN: + BrotliStateMetablockBegin(s); + BROTLI_LOG_UINT(s->pos); + s->state = BROTLI_STATE_METABLOCK_HEADER; + /* No break, continue to next state */ + case BROTLI_STATE_METABLOCK_HEADER: + result = DecodeMetaBlockLength(s, br); /* Reads 2 - 31 bits. */ + if (result != BROTLI_SUCCESS) { + break; + } + BROTLI_LOG_UINT(s->is_last_metablock); + BROTLI_LOG_UINT(s->meta_block_remaining_len); + BROTLI_LOG_UINT(s->is_metadata); + BROTLI_LOG_UINT(s->is_uncompressed); + if (s->is_metadata || s->is_uncompressed) { + if (!BrotliJumpToByteBoundary(br)) { + result = BROTLI_FAILURE(BROTLI_ERROR_FORMAT_PADDING_1); + break; + } + } + if (s->is_metadata) { + s->state = BROTLI_STATE_METADATA; + break; + } + if (s->meta_block_remaining_len == 0) { + s->state = BROTLI_STATE_METABLOCK_DONE; + break; + } + if (!s->ringbuffer) { + BrotliCalculateRingBufferSize(s, br); + } + if (s->is_uncompressed) { + s->state = BROTLI_STATE_UNCOMPRESSED; + break; + } + s->loop_counter = 0; + s->state = BROTLI_STATE_HUFFMAN_CODE_0; + break; + case BROTLI_STATE_UNCOMPRESSED: { + int bytes_copied = s->meta_block_remaining_len; + result = CopyUncompressedBlockToOutput( + available_out, next_out, total_out, s); + bytes_copied -= s->meta_block_remaining_len; + if (result != BROTLI_SUCCESS) { + break; + } + s->state = BROTLI_STATE_METABLOCK_DONE; + break; + } + case BROTLI_STATE_METADATA: + for (; s->meta_block_remaining_len > 0; --s->meta_block_remaining_len) { + uint32_t bits; + /* Read one byte and ignore it. */ + if (!BrotliSafeReadBits(br, 8, &bits)) { + result = BROTLI_NEEDS_MORE_INPUT; + break; + } + } + if (result == BROTLI_SUCCESS) { + s->state = BROTLI_STATE_METABLOCK_DONE; + } + break; + case BROTLI_STATE_HUFFMAN_CODE_0: + if (s->loop_counter >= 3) { + s->state = BROTLI_STATE_METABLOCK_HEADER_2; + break; + } + /* Reads 1..11 bits. */ + result = DecodeVarLenUint8(s, br, &s->num_block_types[s->loop_counter]); + if (result != BROTLI_SUCCESS) { + break; + } + s->num_block_types[s->loop_counter]++; + BROTLI_LOG_UINT(s->num_block_types[s->loop_counter]); + if (s->num_block_types[s->loop_counter] < 2) { + s->loop_counter++; + break; + } + s->state = BROTLI_STATE_HUFFMAN_CODE_1; + /* No break, continue to next state */ + case BROTLI_STATE_HUFFMAN_CODE_1: { + int tree_offset = s->loop_counter * BROTLI_HUFFMAN_MAX_SIZE_258; + result = ReadHuffmanCode(s->num_block_types[s->loop_counter] + 2, + &s->block_type_trees[tree_offset], NULL, s); + if (result != BROTLI_SUCCESS) break; + s->state = BROTLI_STATE_HUFFMAN_CODE_2; + /* No break, continue to next state */ + } + case BROTLI_STATE_HUFFMAN_CODE_2: { + int tree_offset = s->loop_counter * BROTLI_HUFFMAN_MAX_SIZE_26; + result = ReadHuffmanCode(kNumBlockLengthCodes, + &s->block_len_trees[tree_offset], NULL, s); + if (result != BROTLI_SUCCESS) break; + s->state = BROTLI_STATE_HUFFMAN_CODE_3; + /* No break, continue to next state */ + } + case BROTLI_STATE_HUFFMAN_CODE_3: { + int tree_offset = s->loop_counter * BROTLI_HUFFMAN_MAX_SIZE_26; + if (!SafeReadBlockLength(s, &s->block_length[s->loop_counter], + &s->block_len_trees[tree_offset], br)) { + result = BROTLI_NEEDS_MORE_INPUT; + break; + } + BROTLI_LOG_UINT(s->block_length[s->loop_counter]); + s->loop_counter++; + s->state = BROTLI_STATE_HUFFMAN_CODE_0; + break; + } + case BROTLI_STATE_METABLOCK_HEADER_2: { + uint32_t bits; + if (!BrotliSafeReadBits(br, 6, &bits)) { + result = BROTLI_NEEDS_MORE_INPUT; + break; + } + s->distance_postfix_bits = bits & BitMask(2); + bits >>= 2; + s->num_direct_distance_codes = + NUM_DISTANCE_SHORT_CODES + (bits << s->distance_postfix_bits); + BROTLI_LOG_UINT(s->num_direct_distance_codes); + BROTLI_LOG_UINT(s->distance_postfix_bits); + s->distance_postfix_mask = (int)BitMask(s->distance_postfix_bits); + s->context_modes = + (uint8_t*)BROTLI_ALLOC(s, (size_t)s->num_block_types[0]); + if (s->context_modes == 0) { + result = BROTLI_FAILURE(BROTLI_ERROR_ALLOC_CONTEXT_MODES); + break; + } + s->loop_counter = 0; + s->state = BROTLI_STATE_CONTEXT_MODES; + /* No break, continue to next state */ + } + case BROTLI_STATE_CONTEXT_MODES: + result = ReadContextModes(s); + if (result != BROTLI_SUCCESS) { + break; + } + s->state = BROTLI_STATE_CONTEXT_MAP_1; + /* No break, continue to next state */ + case BROTLI_STATE_CONTEXT_MAP_1: + result = DecodeContextMap( + s->num_block_types[0] << kLiteralContextBits, + &s->num_literal_htrees, &s->context_map, s); + if (result != BROTLI_SUCCESS) { + break; + } + DetectTrivialLiteralBlockTypes(s); + s->state = BROTLI_STATE_CONTEXT_MAP_2; + /* No break, continue to next state */ + case BROTLI_STATE_CONTEXT_MAP_2: + { + uint32_t num_distance_codes = + s->num_direct_distance_codes + (48U << s->distance_postfix_bits); + result = DecodeContextMap( + s->num_block_types[2] << kDistanceContextBits, + &s->num_dist_htrees, &s->dist_context_map, s); + if (result != BROTLI_SUCCESS) { + break; + } + BrotliHuffmanTreeGroupInit(s, &s->literal_hgroup, kNumLiteralCodes, + s->num_literal_htrees); + BrotliHuffmanTreeGroupInit(s, &s->insert_copy_hgroup, + kNumInsertAndCopyCodes, + s->num_block_types[1]); + BrotliHuffmanTreeGroupInit(s, &s->distance_hgroup, num_distance_codes, + s->num_dist_htrees); + if (s->literal_hgroup.codes == 0 || + s->insert_copy_hgroup.codes == 0 || + s->distance_hgroup.codes == 0) { + return SaveErrorCode(s, + BROTLI_FAILURE(BROTLI_ERROR_ALLOC_TREE_GROUPS)); + } + } + s->loop_counter = 0; + s->state = BROTLI_STATE_TREE_GROUP; + /* No break, continue to next state */ + case BROTLI_STATE_TREE_GROUP: + { + HuffmanTreeGroup* hgroup = NULL; + switch (s->loop_counter) { + case 0: + hgroup = &s->literal_hgroup; + break; + case 1: + hgroup = &s->insert_copy_hgroup; + break; + case 2: + hgroup = &s->distance_hgroup; + break; + default: + return SaveErrorCode(s, + BROTLI_FAILURE(BROTLI_ERROR_UNREACHABLE)); + } + result = HuffmanTreeGroupDecode(hgroup, s); + } + if (result != BROTLI_SUCCESS) break; + s->loop_counter++; + if (s->loop_counter >= 3) { + PrepareLiteralDecoding(s); + s->dist_context_map_slice = s->dist_context_map; + s->htree_command = s->insert_copy_hgroup.htrees[0]; + if (!s->ringbuffer && !BrotliAllocateRingBuffer(s)) { + result = BROTLI_FAILURE(BROTLI_ERROR_ALLOC_RING_BUFFER_2); + break; + } + s->state = BROTLI_STATE_COMMAND_BEGIN; + } + break; + case BROTLI_STATE_COMMAND_BEGIN: + case BROTLI_STATE_COMMAND_INNER: + case BROTLI_STATE_COMMAND_POST_DECODE_LITERALS: + case BROTLI_STATE_COMMAND_POST_WRAP_COPY: + result = ProcessCommands(s); + if (result == BROTLI_NEEDS_MORE_INPUT) { + result = SafeProcessCommands(s); + } + break; + case BROTLI_STATE_COMMAND_INNER_WRITE: + case BROTLI_STATE_COMMAND_POST_WRITE_1: + case BROTLI_STATE_COMMAND_POST_WRITE_2: + result = WriteRingBuffer(available_out, next_out, total_out, s); + if (result != BROTLI_SUCCESS) { + break; + } + s->max_distance = s->max_backward_distance; + if (s->state == BROTLI_STATE_COMMAND_POST_WRITE_1) { + memcpy(s->ringbuffer, s->ringbuffer_end, (size_t)s->pos); + if (s->meta_block_remaining_len == 0) { + /* Next metablock, if any */ + s->state = BROTLI_STATE_METABLOCK_DONE; + } else { + s->state = BROTLI_STATE_COMMAND_BEGIN; + } + break; + } else if (s->state == BROTLI_STATE_COMMAND_POST_WRITE_2) { + s->state = BROTLI_STATE_COMMAND_POST_WRAP_COPY; + } else { /* BROTLI_STATE_COMMAND_INNER_WRITE */ + if (s->loop_counter == 0) { + if (s->meta_block_remaining_len == 0) { + s->state = BROTLI_STATE_METABLOCK_DONE; + } else { + s->state = BROTLI_STATE_COMMAND_POST_DECODE_LITERALS; + } + break; + } + s->state = BROTLI_STATE_COMMAND_INNER; + } + break; + case BROTLI_STATE_METABLOCK_DONE: + if (s->meta_block_remaining_len < 0) { + result = BROTLI_FAILURE(BROTLI_ERROR_FORMAT_BLOCK_LENGTH_2); + break; + } + BrotliStateCleanupAfterMetablock(s); + if (!s->is_last_metablock) { + s->state = BROTLI_STATE_METABLOCK_BEGIN; + break; + } + if (!BrotliJumpToByteBoundary(br)) { + result = BROTLI_FAILURE(BROTLI_ERROR_FORMAT_PADDING_2); + break; + } + if (s->buffer_length == 0) { + BrotliBitReaderUnload(br); + *available_in = br->avail_in; + *next_in = br->next_in; + } + s->state = BROTLI_STATE_DONE; + /* No break, continue to next state */ + case BROTLI_STATE_DONE: + if (s->ringbuffer != 0) { + result = WriteRingBuffer(available_out, next_out, total_out, s); + if (result != BROTLI_SUCCESS) { + break; + } + } + return SaveErrorCode(s, result); + } + } + return SaveErrorCode(s, result); +} + +void BrotliSetCustomDictionary( + size_t size, const uint8_t* dict, BrotliState* s) { + if (size > (1u << 24)) { + return; + } + s->custom_dict = dict; + s->custom_dict_size = (int)size; +} + +BrotliErrorCode BrotliGetErrorCode(const BrotliState* s) { + return (BrotliErrorCode)s->error_code; +} + +const char* BrotliErrorString(BrotliErrorCode c) { + switch (c) { +#define _BROTLI_ERROR_CODE_CASE(PREFIX, NAME, CODE) \ + case BROTLI ## PREFIX ## NAME: return #NAME; +#define _BROTLI_NOTHING + BROTLI_ERROR_CODES_LIST(_BROTLI_ERROR_CODE_CASE, _BROTLI_NOTHING) +#undef _BROTLI_ERROR_CODE_CASE +#undef _BROTLI_NOTHING + default: return "INVALID"; + } +} + +#if defined(__cplusplus) || defined(c_plusplus) +} /* extern "C" */ +#endif |