diff options
Diffstat (limited to 'modules/brotli/dec/decode.c')
| -rw-r--r-- | modules/brotli/dec/decode.c | 2608 |
1 files changed, 2608 insertions, 0 deletions
diff --git a/modules/brotli/dec/decode.c b/modules/brotli/dec/decode.c new file mode 100644 index 0000000000..ae5a3d3fa3 --- /dev/null +++ b/modules/brotli/dec/decode.c @@ -0,0 +1,2608 @@ +/* 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 <brotli/decode.h> + +#include <stdlib.h> /* free, malloc */ +#include <string.h> /* memcpy, memset */ + +#include "../common/constants.h" +#include "../common/context.h" +#include "../common/dictionary.h" +#include "../common/platform.h" +#include "../common/transform.h" +#include "../common/version.h" +#include "./bit_reader.h" +#include "./huffman.h" +#include "./prefix.h" +#include "./state.h" + +#if defined(BROTLI_TARGET_NEON) +#include <arm_neon.h> +#endif + +#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])) + +#define HUFFMAN_TABLE_BITS 8U +#define HUFFMAN_TABLE_MASK 0xFF + +/* 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 uint32_t kRingBufferWriteAheadSlack = 42; + +static const uint8_t kCodeLengthCodeOrder[BROTLI_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, +}; + +BROTLI_BOOL BrotliDecoderSetParameter( + BrotliDecoderState* state, BrotliDecoderParameter p, uint32_t value) { + if (state->state != BROTLI_STATE_UNINITED) return BROTLI_FALSE; + switch (p) { + case BROTLI_DECODER_PARAM_DISABLE_RING_BUFFER_REALLOCATION: + state->canny_ringbuffer_allocation = !!value ? 0 : 1; + return BROTLI_TRUE; + + case BROTLI_DECODER_PARAM_LARGE_WINDOW: + state->large_window = TO_BROTLI_BOOL(!!value); + return BROTLI_TRUE; + + default: return BROTLI_FALSE; + } +} + +BrotliDecoderState* BrotliDecoderCreateInstance( + brotli_alloc_func alloc_func, brotli_free_func free_func, void* opaque) { + BrotliDecoderState* state = 0; + if (!alloc_func && !free_func) { + state = (BrotliDecoderState*)malloc(sizeof(BrotliDecoderState)); + } else if (alloc_func && free_func) { + state = (BrotliDecoderState*)alloc_func(opaque, sizeof(BrotliDecoderState)); + } + if (state == 0) { + BROTLI_DUMP(); + return 0; + } + if (!BrotliDecoderStateInit(state, alloc_func, free_func, opaque)) { + BROTLI_DUMP(); + if (!alloc_func && !free_func) { + free(state); + } else if (alloc_func && free_func) { + free_func(opaque, state); + } + return 0; + } + return state; +} + +/* Deinitializes and frees BrotliDecoderState instance. */ +void BrotliDecoderDestroyInstance(BrotliDecoderState* state) { + if (!state) { + return; + } else { + brotli_free_func free_func = state->free_func; + void* opaque = state->memory_manager_opaque; + BrotliDecoderStateCleanup(state); + free_func(opaque, state); + } +} + +/* Saves error code and converts it to BrotliDecoderResult. */ +static BROTLI_NOINLINE BrotliDecoderResult SaveErrorCode( + BrotliDecoderState* s, BrotliDecoderErrorCode e) { + s->error_code = (int)e; + switch (e) { + case BROTLI_DECODER_SUCCESS: + return BROTLI_DECODER_RESULT_SUCCESS; + + case BROTLI_DECODER_NEEDS_MORE_INPUT: + return BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT; + + case BROTLI_DECODER_NEEDS_MORE_OUTPUT: + return BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT; + + default: + return BROTLI_DECODER_RESULT_ERROR; + } +} + +/* Decodes WBITS by reading 1 - 7 bits, or 0x11 for "Large Window Brotli". + Precondition: bit-reader accumulator has at least 8 bits. */ +static BrotliDecoderErrorCode DecodeWindowBits(BrotliDecoderState* s, + BrotliBitReader* br) { + uint32_t n; + BROTLI_BOOL large_window = s->large_window; + s->large_window = BROTLI_FALSE; + BrotliTakeBits(br, 1, &n); + if (n == 0) { + s->window_bits = 16; + return BROTLI_DECODER_SUCCESS; + } + BrotliTakeBits(br, 3, &n); + if (n != 0) { + s->window_bits = 17 + n; + return BROTLI_DECODER_SUCCESS; + } + BrotliTakeBits(br, 3, &n); + if (n == 1) { + if (large_window) { + BrotliTakeBits(br, 1, &n); + if (n == 1) { + return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_WINDOW_BITS); + } + s->large_window = BROTLI_TRUE; + return BROTLI_DECODER_SUCCESS; + } else { + return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_WINDOW_BITS); + } + } + if (n != 0) { + s->window_bits = 8 + n; + return BROTLI_DECODER_SUCCESS; + } + s->window_bits = 17; + return BROTLI_DECODER_SUCCESS; +} + +static BROTLI_INLINE void memmove16(uint8_t* dst, uint8_t* src) { +#if defined(BROTLI_TARGET_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 BrotliDecoderErrorCode DecodeVarLenUint8( + BrotliDecoderState* s, BrotliBitReader* br, uint32_t* value) { + uint32_t bits; + switch (s->substate_decode_uint8) { + case BROTLI_STATE_DECODE_UINT8_NONE: + if (BROTLI_PREDICT_FALSE(!BrotliSafeReadBits(br, 1, &bits))) { + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + if (bits == 0) { + *value = 0; + return BROTLI_DECODER_SUCCESS; + } + /* Fall through. */ + + case BROTLI_STATE_DECODE_UINT8_SHORT: + if (BROTLI_PREDICT_FALSE(!BrotliSafeReadBits(br, 3, &bits))) { + s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_SHORT; + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + if (bits == 0) { + *value = 1; + s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_NONE; + return BROTLI_DECODER_SUCCESS; + } + /* Use output value as a temporary storage. It MUST be persisted. */ + *value = bits; + /* Fall through. */ + + case BROTLI_STATE_DECODE_UINT8_LONG: + if (BROTLI_PREDICT_FALSE(!BrotliSafeReadBits(br, *value, &bits))) { + s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_LONG; + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + *value = (1U << *value) + bits; + s->substate_decode_uint8 = BROTLI_STATE_DECODE_UINT8_NONE; + return BROTLI_DECODER_SUCCESS; + + default: + return + BROTLI_FAILURE(BROTLI_DECODER_ERROR_UNREACHABLE); + } +} + +/* Decodes a metablock length and flags by reading 2 - 31 bits. */ +static BrotliDecoderErrorCode BROTLI_NOINLINE DecodeMetaBlockLength( + BrotliDecoderState* 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_DECODER_NEEDS_MORE_INPUT; + } + s->is_last_metablock = bits ? 1 : 0; + 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; + /* Fall through. */ + + case BROTLI_STATE_METABLOCK_HEADER_EMPTY: + if (!BrotliSafeReadBits(br, 1, &bits)) { + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + if (bits) { + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE; + return BROTLI_DECODER_SUCCESS; + } + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NIBBLES; + /* Fall through. */ + + case BROTLI_STATE_METABLOCK_HEADER_NIBBLES: + if (!BrotliSafeReadBits(br, 2, &bits)) { + return BROTLI_DECODER_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; + /* Fall through. */ + + case BROTLI_STATE_METABLOCK_HEADER_SIZE: + i = s->loop_counter; + for (; i < (int)s->size_nibbles; ++i) { + if (!BrotliSafeReadBits(br, 4, &bits)) { + s->loop_counter = i; + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + if (i + 1 == (int)s->size_nibbles && s->size_nibbles > 4 && + bits == 0) { + return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_EXUBERANT_NIBBLE); + } + s->meta_block_remaining_len |= (int)(bits << (i * 4)); + } + s->substate_metablock_header = + BROTLI_STATE_METABLOCK_HEADER_UNCOMPRESSED; + /* Fall through. */ + + case BROTLI_STATE_METABLOCK_HEADER_UNCOMPRESSED: + if (!s->is_last_metablock) { + if (!BrotliSafeReadBits(br, 1, &bits)) { + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + s->is_uncompressed = bits ? 1 : 0; + } + ++s->meta_block_remaining_len; + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE; + return BROTLI_DECODER_SUCCESS; + + case BROTLI_STATE_METABLOCK_HEADER_RESERVED: + if (!BrotliSafeReadBits(br, 1, &bits)) { + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + if (bits != 0) { + return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_RESERVED); + } + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_BYTES; + /* Fall through. */ + + case BROTLI_STATE_METABLOCK_HEADER_BYTES: + if (!BrotliSafeReadBits(br, 2, &bits)) { + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + if (bits == 0) { + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_NONE; + return BROTLI_DECODER_SUCCESS; + } + s->size_nibbles = (uint8_t)bits; + s->substate_metablock_header = BROTLI_STATE_METABLOCK_HEADER_METADATA; + /* Fall through. */ + + case BROTLI_STATE_METABLOCK_HEADER_METADATA: + i = s->loop_counter; + for (; i < (int)s->size_nibbles; ++i) { + if (!BrotliSafeReadBits(br, 8, &bits)) { + s->loop_counter = i; + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + if (i + 1 == (int)s->size_nibbles && s->size_nibbles > 1 && + bits == 0) { + return BROTLI_FAILURE( + BROTLI_DECODER_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_DECODER_SUCCESS; + + default: + return + BROTLI_FAILURE(BROTLI_DECODER_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) { + BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(table); + BROTLI_HC_ADJUST_TABLE_INDEX(table, bits & HUFFMAN_TABLE_MASK); + if (BROTLI_HC_FAST_LOAD_BITS(table) > HUFFMAN_TABLE_BITS) { + uint32_t nbits = BROTLI_HC_FAST_LOAD_BITS(table) - HUFFMAN_TABLE_BITS; + BrotliDropBits(br, HUFFMAN_TABLE_BITS); + BROTLI_HC_ADJUST_TABLE_INDEX(table, + BROTLI_HC_FAST_LOAD_VALUE(table) + + ((bits >> HUFFMAN_TABLE_BITS) & BitMask(nbits))); + } + BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(table)); + return BROTLI_HC_FAST_LOAD_VALUE(table); +} + +/* 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 BROTLI_BOOL SafeDecodeSymbol( + const HuffmanCode* table, BrotliBitReader* br, uint32_t* result) { + uint32_t val; + uint32_t available_bits = BrotliGetAvailableBits(br); + BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(table); + if (available_bits == 0) { + if (BROTLI_HC_FAST_LOAD_BITS(table) == 0) { + *result = BROTLI_HC_FAST_LOAD_VALUE(table); + return BROTLI_TRUE; + } + return BROTLI_FALSE; /* No valid bits at all. */ + } + val = (uint32_t)BrotliGetBitsUnmasked(br); + BROTLI_HC_ADJUST_TABLE_INDEX(table, val & HUFFMAN_TABLE_MASK); + if (BROTLI_HC_FAST_LOAD_BITS(table) <= HUFFMAN_TABLE_BITS) { + if (BROTLI_HC_FAST_LOAD_BITS(table) <= available_bits) { + BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(table)); + *result = BROTLI_HC_FAST_LOAD_VALUE(table); + return BROTLI_TRUE; + } else { + return BROTLI_FALSE; /* Not enough bits for the first level. */ + } + } + if (available_bits <= HUFFMAN_TABLE_BITS) { + return BROTLI_FALSE; /* Not enough bits to move to the second level. */ + } + + /* Speculatively drop HUFFMAN_TABLE_BITS. */ + val = (val & BitMask(BROTLI_HC_FAST_LOAD_BITS(table))) >> HUFFMAN_TABLE_BITS; + available_bits -= HUFFMAN_TABLE_BITS; + BROTLI_HC_ADJUST_TABLE_INDEX(table, BROTLI_HC_FAST_LOAD_VALUE(table) + val); + if (available_bits < BROTLI_HC_FAST_LOAD_BITS(table)) { + return BROTLI_FALSE; /* Not enough bits for the second level. */ + } + + BrotliDropBits(br, HUFFMAN_TABLE_BITS + BROTLI_HC_FAST_LOAD_BITS(table)); + *result = BROTLI_HC_FAST_LOAD_VALUE(table); + return BROTLI_TRUE; +} + +static BROTLI_INLINE BROTLI_BOOL SafeReadSymbol( + const HuffmanCode* table, BrotliBitReader* br, uint32_t* result) { + uint32_t val; + if (BROTLI_PREDICT_TRUE(BrotliSafeGetBits(br, 15, &val))) { + *result = DecodeSymbol(val, table, br); + return BROTLI_TRUE; + } + 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; + } + BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(table); + BROTLI_HC_ADJUST_TABLE_INDEX(table, BrotliGetBits(br, HUFFMAN_TABLE_BITS)); + *bits = BROTLI_HC_FAST_LOAD_BITS(table); + *value = BROTLI_HC_FAST_LOAD_VALUE(table); +} + +/* 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 (BROTLI_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)); + BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(ext); + BrotliDropBits(br, HUFFMAN_TABLE_BITS); + BROTLI_HC_ADJUST_TABLE_INDEX(ext, (val >> HUFFMAN_TABLE_BITS) & mask); + BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(ext)); + result = BROTLI_HC_FAST_LOAD_VALUE(ext); + } 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..11 bits each. + The list of symbols MUST NOT contain duplicates. */ +static BrotliDecoderErrorCode ReadSimpleHuffmanSymbols( + uint32_t alphabet_size_max, uint32_t alphabet_size_limit, + BrotliDecoderState* s) { + /* max_bits == 1..11; symbol == 0..3; 1..44 bits will be read. */ + BrotliBitReader* br = &s->br; + BrotliMetablockHeaderArena* h = &s->arena.header; + uint32_t max_bits = Log2Floor(alphabet_size_max - 1); + uint32_t i = h->sub_loop_counter; + uint32_t num_symbols = h->symbol; + while (i <= num_symbols) { + uint32_t v; + if (BROTLI_PREDICT_FALSE(!BrotliSafeReadBits(br, max_bits, &v))) { + h->sub_loop_counter = i; + h->substate_huffman = BROTLI_STATE_HUFFMAN_SIMPLE_READ; + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + if (v >= alphabet_size_limit) { + return + BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_ALPHABET); + } + h->symbols_lists_array[i] = (uint16_t)v; + BROTLI_LOG_UINT(h->symbols_lists_array[i]); + ++i; + } + + for (i = 0; i < num_symbols; ++i) { + uint32_t k = i + 1; + for (; k <= num_symbols; ++k) { + if (h->symbols_lists_array[i] == h->symbols_lists_array[k]) { + return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_SIMPLE_HUFFMAN_SAME); + } + } + } + + return BROTLI_DECODER_SUCCESS; +} + +/* Process single decoded symbol code length: + A) reset the repeat variable + B) remember code length (if it is not 0) + C) extend corresponding 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", + (int)*symbol, (int)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 BROTLI_REPEAT_PREVIOUS_CODE_LENGTH, then it is a new + symbol-skip + B) Update repeat variable + C) Check if operation is feasible (fits alphabet) + D) For each symbol do the same operations as in ProcessSingleCodeLength + + PRECONDITION: code_len == BROTLI_REPEAT_PREVIOUS_CODE_LENGTH or + code_len == BROTLI_REPEAT_ZERO_CODE_LENGTH */ +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 extra_bits = 3; /* for BROTLI_REPEAT_ZERO_CODE_LENGTH */ + uint32_t new_len = 0; /* for BROTLI_REPEAT_ZERO_CODE_LENGTH */ + if (code_len == BROTLI_REPEAT_PREVIOUS_CODE_LENGTH) { + new_len = *prev_code_len; + extra_bits = 2; + } + if (*repeat_code_len != new_len) { + *repeat = 0; + *repeat_code_len = new_len; + } + old_repeat = *repeat; + if (*repeat > 0) { + *repeat -= 2; + *repeat <<= extra_bits; + } + *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", + (int)*symbol, (int)(*symbol + repeat_delta - 1), (int)*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 BrotliDecoderErrorCode ReadSymbolCodeLengths( + uint32_t alphabet_size, BrotliDecoderState* s) { + BrotliBitReader* br = &s->br; + BrotliMetablockHeaderArena* h = &s->arena.header; + uint32_t symbol = h->symbol; + uint32_t repeat = h->repeat; + uint32_t space = h->space; + uint32_t prev_code_len = h->prev_code_len; + uint32_t repeat_code_len = h->repeat_code_len; + uint16_t* symbol_lists = h->symbol_lists; + uint16_t* code_length_histo = h->code_length_histo; + int* next_symbol = h->next_symbol; + if (!BrotliWarmupBitReader(br)) { + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + while (symbol < alphabet_size && space > 0) { + const HuffmanCode* p = h->table; + uint32_t code_len; + BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(p); + if (!BrotliCheckInputAmount(br, BROTLI_SHORT_FILL_BIT_WINDOW_READ)) { + h->symbol = symbol; + h->repeat = repeat; + h->prev_code_len = prev_code_len; + h->repeat_code_len = repeat_code_len; + h->space = space; + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + BrotliFillBitWindow16(br); + BROTLI_HC_ADJUST_TABLE_INDEX(p, BrotliGetBitsUnmasked(br) & + BitMask(BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH)); + BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(p)); /* Use 1..5 bits. */ + code_len = BROTLI_HC_FAST_LOAD_VALUE(p); /* code_len == 0..17 */ + if (code_len < BROTLI_REPEAT_PREVIOUS_CODE_LENGTH) { + 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 extra_bits = + (code_len == BROTLI_REPEAT_PREVIOUS_CODE_LENGTH) ? 2 : 3; + uint32_t repeat_delta = + (uint32_t)BrotliGetBitsUnmasked(br) & BitMask(extra_bits); + BrotliDropBits(br, extra_bits); + ProcessRepeatedCodeLength(code_len, repeat_delta, alphabet_size, + &symbol, &repeat, &space, &prev_code_len, &repeat_code_len, + symbol_lists, code_length_histo, next_symbol); + } + } + h->space = space; + return BROTLI_DECODER_SUCCESS; +} + +static BrotliDecoderErrorCode SafeReadSymbolCodeLengths( + uint32_t alphabet_size, BrotliDecoderState* s) { + BrotliBitReader* br = &s->br; + BrotliMetablockHeaderArena* h = &s->arena.header; + BROTLI_BOOL get_byte = BROTLI_FALSE; + while (h->symbol < alphabet_size && h->space > 0) { + const HuffmanCode* p = h->table; + uint32_t code_len; + uint32_t available_bits; + uint32_t bits = 0; + BROTLI_HC_MARK_TABLE_FOR_FAST_LOAD(p); + if (get_byte && !BrotliPullByte(br)) return BROTLI_DECODER_NEEDS_MORE_INPUT; + get_byte = BROTLI_FALSE; + available_bits = BrotliGetAvailableBits(br); + if (available_bits != 0) { + bits = (uint32_t)BrotliGetBitsUnmasked(br); + } + BROTLI_HC_ADJUST_TABLE_INDEX(p, + bits & BitMask(BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH)); + if (BROTLI_HC_FAST_LOAD_BITS(p) > available_bits) { + get_byte = BROTLI_TRUE; + continue; + } + code_len = BROTLI_HC_FAST_LOAD_VALUE(p); /* code_len == 0..17 */ + if (code_len < BROTLI_REPEAT_PREVIOUS_CODE_LENGTH) { + BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(p)); + ProcessSingleCodeLength(code_len, &h->symbol, &h->repeat, &h->space, + &h->prev_code_len, h->symbol_lists, h->code_length_histo, + h->next_symbol); + } else { /* code_len == 16..17, extra_bits == 2..3 */ + uint32_t extra_bits = code_len - 14U; + uint32_t repeat_delta = (bits >> BROTLI_HC_FAST_LOAD_BITS(p)) & + BitMask(extra_bits); + if (available_bits < BROTLI_HC_FAST_LOAD_BITS(p) + extra_bits) { + get_byte = BROTLI_TRUE; + continue; + } + BrotliDropBits(br, BROTLI_HC_FAST_LOAD_BITS(p) + extra_bits); + ProcessRepeatedCodeLength(code_len, repeat_delta, alphabet_size, + &h->symbol, &h->repeat, &h->space, &h->prev_code_len, + &h->repeat_code_len, h->symbol_lists, h->code_length_histo, + h->next_symbol); + } + } + return BROTLI_DECODER_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 BrotliDecoderErrorCode ReadCodeLengthCodeLengths(BrotliDecoderState* s) { + BrotliBitReader* br = &s->br; + BrotliMetablockHeaderArena* h = &s->arena.header; + uint32_t num_codes = h->repeat; + unsigned space = h->space; + uint32_t i = h->sub_loop_counter; + for (; i < BROTLI_CODE_LENGTH_CODES; ++i) { + const uint8_t code_len_idx = kCodeLengthCodeOrder[i]; + uint32_t ix; + uint32_t v; + if (BROTLI_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) { + h->sub_loop_counter = i; + h->repeat = num_codes; + h->space = space; + h->substate_huffman = BROTLI_STATE_HUFFMAN_COMPLEX; + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + } + v = kCodeLengthPrefixValue[ix]; + BrotliDropBits(br, kCodeLengthPrefixLength[ix]); + h->code_length_code_lengths[code_len_idx] = (uint8_t)v; + BROTLI_LOG_ARRAY_INDEX(h->code_length_code_lengths, code_len_idx); + if (v != 0) { + space = space - (32U >> v); + ++num_codes; + ++h->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_DECODER_ERROR_FORMAT_CL_SPACE); + } + return BROTLI_DECODER_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 - 49 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 BrotliDecoderErrorCode ReadHuffmanCode(uint32_t alphabet_size_max, + uint32_t alphabet_size_limit, + HuffmanCode* table, + uint32_t* opt_table_size, + BrotliDecoderState* s) { + BrotliBitReader* br = &s->br; + BrotliMetablockHeaderArena* h = &s->arena.header; + /* State machine. */ + for (;;) { + switch (h->substate_huffman) { + case BROTLI_STATE_HUFFMAN_NONE: + if (!BrotliSafeReadBits(br, 2, &h->sub_loop_counter)) { + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + BROTLI_LOG_UINT(h->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 (h->sub_loop_counter != 1) { + h->space = 32; + h->repeat = 0; /* num_codes */ + memset(&h->code_length_histo[0], 0, sizeof(h->code_length_histo[0]) * + (BROTLI_HUFFMAN_MAX_CODE_LENGTH_CODE_LENGTH + 1)); + memset(&h->code_length_code_lengths[0], 0, + sizeof(h->code_length_code_lengths)); + h->substate_huffman = BROTLI_STATE_HUFFMAN_COMPLEX; + continue; + } + /* Fall through. */ + + case BROTLI_STATE_HUFFMAN_SIMPLE_SIZE: + /* Read symbols, codes & code lengths directly. */ + if (!BrotliSafeReadBits(br, 2, &h->symbol)) { /* num_symbols */ + h->substate_huffman = BROTLI_STATE_HUFFMAN_SIMPLE_SIZE; + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + h->sub_loop_counter = 0; + /* Fall through. */ + + case BROTLI_STATE_HUFFMAN_SIMPLE_READ: { + BrotliDecoderErrorCode result = + ReadSimpleHuffmanSymbols(alphabet_size_max, alphabet_size_limit, s); + if (result != BROTLI_DECODER_SUCCESS) { + return result; + } + } + /* Fall through. */ + + case BROTLI_STATE_HUFFMAN_SIMPLE_BUILD: { + uint32_t table_size; + if (h->symbol == 3) { + uint32_t bits; + if (!BrotliSafeReadBits(br, 1, &bits)) { + h->substate_huffman = BROTLI_STATE_HUFFMAN_SIMPLE_BUILD; + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + h->symbol += bits; + } + BROTLI_LOG_UINT(h->symbol); + table_size = BrotliBuildSimpleHuffmanTable( + table, HUFFMAN_TABLE_BITS, h->symbols_lists_array, h->symbol); + if (opt_table_size) { + *opt_table_size = table_size; + } + h->substate_huffman = BROTLI_STATE_HUFFMAN_NONE; + return BROTLI_DECODER_SUCCESS; + } + + /* Decode Huffman-coded code lengths. */ + case BROTLI_STATE_HUFFMAN_COMPLEX: { + uint32_t i; + BrotliDecoderErrorCode result = ReadCodeLengthCodeLengths(s); + if (result != BROTLI_DECODER_SUCCESS) { + return result; + } + BrotliBuildCodeLengthsHuffmanTable(h->table, + h->code_length_code_lengths, + h->code_length_histo); + memset(&h->code_length_histo[0], 0, sizeof(h->code_length_histo)); + for (i = 0; i <= BROTLI_HUFFMAN_MAX_CODE_LENGTH; ++i) { + h->next_symbol[i] = (int)i - (BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1); + h->symbol_lists[h->next_symbol[i]] = 0xFFFF; + } + + h->symbol = 0; + h->prev_code_len = BROTLI_INITIAL_REPEATED_CODE_LENGTH; + h->repeat = 0; + h->repeat_code_len = 0; + h->space = 32768; + h->substate_huffman = BROTLI_STATE_HUFFMAN_LENGTH_SYMBOLS; + } + /* Fall through. */ + + case BROTLI_STATE_HUFFMAN_LENGTH_SYMBOLS: { + uint32_t table_size; + BrotliDecoderErrorCode result = ReadSymbolCodeLengths( + alphabet_size_limit, s); + if (result == BROTLI_DECODER_NEEDS_MORE_INPUT) { + result = SafeReadSymbolCodeLengths(alphabet_size_limit, s); + } + if (result != BROTLI_DECODER_SUCCESS) { + return result; + } + + if (h->space != 0) { + BROTLI_LOG(("[ReadHuffmanCode] space = %d\n", (int)h->space)); + return BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_HUFFMAN_SPACE); + } + table_size = BrotliBuildHuffmanTable( + table, HUFFMAN_TABLE_BITS, h->symbol_lists, h->code_length_histo); + if (opt_table_size) { + *opt_table_size = table_size; + } + h->substate_huffman = BROTLI_STATE_HUFFMAN_NONE; + return BROTLI_DECODER_SUCCESS; + } + + default: + return + BROTLI_FAILURE(BROTLI_DECODER_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 = _kBrotliPrefixCodeRanges[code].nbits; /* nbits == 2..24 */ + return _kBrotliPrefixCodeRanges[code].offset + BrotliReadBits24(br, nbits); +} + +/* WARNING: if state is not BROTLI_STATE_READ_BLOCK_LENGTH_NONE, then + reading can't be continued with ReadBlockLength. */ +static BROTLI_INLINE BROTLI_BOOL SafeReadBlockLength( + BrotliDecoderState* 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 BROTLI_FALSE; + } + } else { + index = s->block_length_index; + } + { + uint32_t bits; + uint32_t nbits = _kBrotliPrefixCodeRanges[index].nbits; + uint32_t offset = _kBrotliPrefixCodeRanges[index].offset; + if (!BrotliSafeReadBits(br, nbits, &bits)) { + s->block_length_index = index; + s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_SUFFIX; + return BROTLI_FALSE; + } + *result = offset + bits; + s->substate_read_block_length = BROTLI_STATE_READ_BLOCK_LENGTH_NONE; + return BROTLI_TRUE; + } +} + +/* 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, BrotliDecoderState* state) { + /* Reinitialize elements that could have been changed. */ + uint32_t i = 1; + uint32_t upper_bound = state->mtf_upper_bound; + uint32_t* mtf = &state->mtf[1]; /* Make mtf[-1] addressable. */ + uint8_t* mtf_u8 = (uint8_t*)mtf; + /* 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. */ + mtf[0] = pattern; + do { + pattern += 0x04040404; /* Advance all 4 values by 4. */ + mtf[i] = pattern; + i++; + } 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_u8[index]; + upper_bound |= v[i]; + v[i] = value; + mtf_u8[-1] = value; + do { + index--; + mtf_u8[index + 1] = mtf_u8[index]; + } while (index >= 0); + } + /* Remember amount of elements to be reinitialized. */ + state->mtf_upper_bound = upper_bound >> 2; +} + +/* Decodes a series of Huffman table using ReadHuffmanCode function. */ +static BrotliDecoderErrorCode HuffmanTreeGroupDecode( + HuffmanTreeGroup* group, BrotliDecoderState* s) { + BrotliMetablockHeaderArena* h = &s->arena.header; + if (h->substate_tree_group != BROTLI_STATE_TREE_GROUP_LOOP) { + h->next = group->codes; + h->htree_index = 0; + h->substate_tree_group = BROTLI_STATE_TREE_GROUP_LOOP; + } + while (h->htree_index < group->num_htrees) { + uint32_t table_size; + BrotliDecoderErrorCode result = ReadHuffmanCode(group->alphabet_size_max, + group->alphabet_size_limit, h->next, &table_size, s); + if (result != BROTLI_DECODER_SUCCESS) return result; + group->htrees[h->htree_index] = h->next; + h->next += table_size; + ++h->htree_index; + } + h->substate_tree_group = BROTLI_STATE_TREE_GROUP_NONE; + return BROTLI_DECODER_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 BrotliDecoderErrorCode DecodeContextMap(uint32_t context_map_size, + uint32_t* num_htrees, + uint8_t** context_map_arg, + BrotliDecoderState* s) { + BrotliBitReader* br = &s->br; + BrotliDecoderErrorCode result = BROTLI_DECODER_SUCCESS; + BrotliMetablockHeaderArena* h = &s->arena.header; + + switch ((int)h->substate_context_map) { + case BROTLI_STATE_CONTEXT_MAP_NONE: + result = DecodeVarLenUint8(s, br, num_htrees); + if (result != BROTLI_DECODER_SUCCESS) { + return result; + } + (*num_htrees)++; + h->context_index = 0; + BROTLI_LOG_UINT(context_map_size); + BROTLI_LOG_UINT(*num_htrees); + *context_map_arg = + (uint8_t*)BROTLI_DECODER_ALLOC(s, (size_t)context_map_size); + if (*context_map_arg == 0) { + return BROTLI_FAILURE(BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MAP); + } + if (*num_htrees <= 1) { + memset(*context_map_arg, 0, (size_t)context_map_size); + return BROTLI_DECODER_SUCCESS; + } + h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_READ_PREFIX; + /* Fall through. */ + + 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_DECODER_NEEDS_MORE_INPUT; + } + if ((bits & 1) != 0) { /* Use RLE for zeros. */ + h->max_run_length_prefix = (bits >> 1) + 1; + BrotliDropBits(br, 5); + } else { + h->max_run_length_prefix = 0; + BrotliDropBits(br, 1); + } + BROTLI_LOG_UINT(h->max_run_length_prefix); + h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_HUFFMAN; + } + /* Fall through. */ + + case BROTLI_STATE_CONTEXT_MAP_HUFFMAN: { + uint32_t alphabet_size = *num_htrees + h->max_run_length_prefix; + result = ReadHuffmanCode(alphabet_size, alphabet_size, + h->context_map_table, NULL, s); + if (result != BROTLI_DECODER_SUCCESS) return result; + h->code = 0xFFFF; + h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_DECODE; + } + /* Fall through. */ + + case BROTLI_STATE_CONTEXT_MAP_DECODE: { + uint32_t context_index = h->context_index; + uint32_t max_run_length_prefix = h->max_run_length_prefix; + uint8_t* context_map = *context_map_arg; + uint32_t code = h->code; + BROTLI_BOOL skip_preamble = (code != 0xFFFF); + while (context_index < context_map_size || skip_preamble) { + if (!skip_preamble) { + if (!SafeReadSymbol(h->context_map_table, br, &code)) { + h->code = 0xFFFF; + h->context_index = context_index; + return BROTLI_DECODER_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; + } + } else { + skip_preamble = BROTLI_FALSE; + } + /* RLE sub-stage. */ + { + uint32_t reps; + if (!BrotliSafeReadBits(br, code, &reps)) { + h->code = code; + h->context_index = context_index; + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + reps += 1U << code; + BROTLI_LOG_UINT(reps); + if (context_index + reps > context_map_size) { + return + BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_CONTEXT_MAP_REPEAT); + } + do { + context_map[context_index++] = 0; + } while (--reps); + } + } + } + /* Fall through. */ + + case BROTLI_STATE_CONTEXT_MAP_TRANSFORM: { + uint32_t bits; + if (!BrotliSafeReadBits(br, 1, &bits)) { + h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_TRANSFORM; + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + if (bits != 0) { + InverseMoveToFrontTransform(*context_map_arg, context_map_size, s); + } + h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_NONE; + return BROTLI_DECODER_SUCCESS; + } + + default: + return + BROTLI_FAILURE(BROTLI_DECODER_ERROR_UNREACHABLE); + } +} + +/* Decodes a command or literal and updates block type ring-buffer. + Reads 3..54 bits. */ +static BROTLI_INLINE BROTLI_BOOL DecodeBlockTypeAndLength( + int safe, BrotliDecoderState* 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; + if (max_block_type <= 1) { + return BROTLI_FALSE; + } + + /* 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 BROTLI_FALSE; + 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 BROTLI_FALSE; + } + } + + 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 BROTLI_TRUE; +} + +static BROTLI_INLINE void DetectTrivialLiteralBlockTypes( + BrotliDecoderState* 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 << BROTLI_LITERAL_CONTEXT_BITS; + size_t error = 0; + size_t sample = s->context_map[offset]; + size_t j; + for (j = 0; j < (1u << BROTLI_LITERAL_CONTEXT_BITS);) { + 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(BrotliDecoderState* s) { + uint8_t context_mode; + size_t trivial; + uint32_t block_type = s->block_type_rb[1]; + uint32_t context_offset = block_type << BROTLI_LITERAL_CONTEXT_BITS; + 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] & 3; + s->context_lookup = BROTLI_CONTEXT_LUT(context_mode); +} + +/* Decodes the block type and updates the state for literal context. + Reads 3..54 bits. */ +static BROTLI_INLINE BROTLI_BOOL DecodeLiteralBlockSwitchInternal( + int safe, BrotliDecoderState* s) { + if (!DecodeBlockTypeAndLength(safe, s, 0)) { + return BROTLI_FALSE; + } + PrepareLiteralDecoding(s); + return BROTLI_TRUE; +} + +static void BROTLI_NOINLINE DecodeLiteralBlockSwitch(BrotliDecoderState* s) { + DecodeLiteralBlockSwitchInternal(0, s); +} + +static BROTLI_BOOL BROTLI_NOINLINE SafeDecodeLiteralBlockSwitch( + BrotliDecoderState* s) { + return DecodeLiteralBlockSwitchInternal(1, s); +} + +/* Block switch for insert/copy length. + Reads 3..54 bits. */ +static BROTLI_INLINE BROTLI_BOOL DecodeCommandBlockSwitchInternal( + int safe, BrotliDecoderState* s) { + if (!DecodeBlockTypeAndLength(safe, s, 1)) { + return BROTLI_FALSE; + } + s->htree_command = s->insert_copy_hgroup.htrees[s->block_type_rb[3]]; + return BROTLI_TRUE; +} + +static void BROTLI_NOINLINE DecodeCommandBlockSwitch(BrotliDecoderState* s) { + DecodeCommandBlockSwitchInternal(0, s); +} + +static BROTLI_BOOL BROTLI_NOINLINE SafeDecodeCommandBlockSwitch( + BrotliDecoderState* s) { + return DecodeCommandBlockSwitchInternal(1, s); +} + +/* Block switch for distance codes. + Reads 3..54 bits. */ +static BROTLI_INLINE BROTLI_BOOL DecodeDistanceBlockSwitchInternal( + int safe, BrotliDecoderState* s) { + if (!DecodeBlockTypeAndLength(safe, s, 2)) { + return BROTLI_FALSE; + } + s->dist_context_map_slice = s->dist_context_map + + (s->block_type_rb[5] << BROTLI_DISTANCE_CONTEXT_BITS); + s->dist_htree_index = s->dist_context_map_slice[s->distance_context]; + return BROTLI_TRUE; +} + +static void BROTLI_NOINLINE DecodeDistanceBlockSwitch(BrotliDecoderState* s) { + DecodeDistanceBlockSwitchInternal(0, s); +} + +static BROTLI_BOOL BROTLI_NOINLINE SafeDecodeDistanceBlockSwitch( + BrotliDecoderState* s) { + return DecodeDistanceBlockSwitchInternal(1, s); +} + +static size_t UnwrittenBytes(const BrotliDecoderState* s, BROTLI_BOOL wrap) { + size_t pos = wrap && s->pos > s->ringbuffer_size ? + (size_t)s->ringbuffer_size : (size_t)(s->pos); + size_t partial_pos_rb = (s->rb_roundtrips * (size_t)s->ringbuffer_size) + pos; + return partial_pos_rb - s->partial_pos_out; +} + +/* Dumps output. + Returns BROTLI_DECODER_NEEDS_MORE_OUTPUT only if there is more output to push + and either ring-buffer is as big as window size, or |force| is true. */ +static BrotliDecoderErrorCode BROTLI_NOINLINE WriteRingBuffer( + BrotliDecoderState* s, size_t* available_out, uint8_t** next_out, + size_t* total_out, BROTLI_BOOL force) { + uint8_t* start = + s->ringbuffer + (s->partial_pos_out & (size_t)s->ringbuffer_mask); + size_t to_write = UnwrittenBytes(s, BROTLI_TRUE); + 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_DECODER_ERROR_FORMAT_BLOCK_LENGTH_1); + } + if (next_out && !*next_out) { + *next_out = start; + } else { + if (next_out) { + 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) { + if (s->ringbuffer_size == (1 << s->window_bits) || force) { + return BROTLI_DECODER_NEEDS_MORE_OUTPUT; + } else { + return BROTLI_DECODER_SUCCESS; + } + } + /* Wrap ring buffer only if it has reached its maximal size. */ + if (s->ringbuffer_size == (1 << s->window_bits) && + s->pos >= s->ringbuffer_size) { + s->pos -= s->ringbuffer_size; + s->rb_roundtrips++; + s->should_wrap_ringbuffer = (size_t)s->pos != 0 ? 1 : 0; + } + return BROTLI_DECODER_SUCCESS; +} + +static void BROTLI_NOINLINE WrapRingBuffer(BrotliDecoderState* s) { + if (s->should_wrap_ringbuffer) { + memcpy(s->ringbuffer, s->ringbuffer_end, (size_t)s->pos); + s->should_wrap_ringbuffer = 0; + } +} + +/* Allocates ring-buffer. + + s->ringbuffer_size MUST be updated by BrotliCalculateRingBufferSize before + this function is called. + + Last two bytes of ring-buffer are initialized to 0, so context calculation + could be done uniformly for the first two and all other positions. */ +static BROTLI_BOOL BROTLI_NOINLINE BrotliEnsureRingBuffer( + BrotliDecoderState* s) { + uint8_t* old_ringbuffer = s->ringbuffer; + if (s->ringbuffer_size == s->new_ringbuffer_size) { + return BROTLI_TRUE; + } + + s->ringbuffer = (uint8_t*)BROTLI_DECODER_ALLOC(s, + (size_t)(s->new_ringbuffer_size) + kRingBufferWriteAheadSlack); + if (s->ringbuffer == 0) { + /* Restore previous value. */ + s->ringbuffer = old_ringbuffer; + return BROTLI_FALSE; + } + s->ringbuffer[s->new_ringbuffer_size - 2] = 0; + s->ringbuffer[s->new_ringbuffer_size - 1] = 0; + + if (!!old_ringbuffer) { + memcpy(s->ringbuffer, old_ringbuffer, (size_t)s->pos); + BROTLI_DECODER_FREE(s, old_ringbuffer); + } + + s->ringbuffer_size = s->new_ringbuffer_size; + s->ringbuffer_mask = s->new_ringbuffer_size - 1; + s->ringbuffer_end = s->ringbuffer + s->ringbuffer_size; + + return BROTLI_TRUE; +} + +static BrotliDecoderErrorCode BROTLI_NOINLINE CopyUncompressedBlockToOutput( + size_t* available_out, uint8_t** next_out, size_t* total_out, + BrotliDecoderState* s) { + /* TODO: avoid allocation for single uncompressed block. */ + if (!BrotliEnsureRingBuffer(s)) { + return BROTLI_FAILURE(BROTLI_DECODER_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 ring-buffer. */ + BrotliCopyBytes(&s->ringbuffer[s->pos], &s->br, (size_t)nbytes); + s->pos += nbytes; + s->meta_block_remaining_len -= nbytes; + if (s->pos < 1 << s->window_bits) { + if (s->meta_block_remaining_len == 0) { + return BROTLI_DECODER_SUCCESS; + } + return BROTLI_DECODER_NEEDS_MORE_INPUT; + } + s->substate_uncompressed = BROTLI_STATE_UNCOMPRESSED_WRITE; + } + /* Fall through. */ + + case BROTLI_STATE_UNCOMPRESSED_WRITE: { + BrotliDecoderErrorCode result; + result = WriteRingBuffer( + s, available_out, next_out, total_out, BROTLI_FALSE); + if (result != BROTLI_DECODER_SUCCESS) { + return result; + } + if (s->ringbuffer_size == 1 << s->window_bits) { + s->max_distance = s->max_backward_distance; + } + s->substate_uncompressed = BROTLI_STATE_UNCOMPRESSED_NONE; + break; + } + } + } + BROTLI_DCHECK(0); /* Unreachable */ +} + +/* Calculates the smallest feasible ring buffer. + + If we know the data size is small, do not allocate more ring buffer + size than needed to reduce memory usage. + + When this method is called, metablock size and flags MUST be decoded. */ +static void BROTLI_NOINLINE BrotliCalculateRingBufferSize( + BrotliDecoderState* s) { + int window_size = 1 << s->window_bits; + int new_ringbuffer_size = window_size; + /* We need at least 2 bytes of ring buffer size to get the last two + bytes for context from there */ + int min_size = s->ringbuffer_size ? s->ringbuffer_size : 1024; + int output_size; + + /* If maximum is already reached, no further extension is retired. */ + if (s->ringbuffer_size == window_size) { + return; + } + + /* Metadata blocks does not touch ring buffer. */ + if (s->is_metadata) { + return; + } + + if (!s->ringbuffer) { + output_size = 0; + } else { + output_size = s->pos; + } + output_size += s->meta_block_remaining_len; + min_size = min_size < output_size ? output_size : min_size; + + if (!!s->canny_ringbuffer_allocation) { + /* Reduce ring buffer size to save memory when server is unscrupulous. + In worst case memory usage might be 1.5x bigger for a short period of + ring buffer reallocation. */ + while ((new_ringbuffer_size >> 1) >= min_size) { + new_ringbuffer_size >>= 1; + } + } + + s->new_ringbuffer_size = new_ringbuffer_size; +} + +/* Reads 1..256 2-bit context modes. */ +static BrotliDecoderErrorCode ReadContextModes(BrotliDecoderState* 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_DECODER_NEEDS_MORE_INPUT; + } + s->context_modes[i] = (uint8_t)bits; + BROTLI_LOG_ARRAY_INDEX(s->context_modes, i); + i++; + } + return BROTLI_DECODER_SUCCESS; +} + +static BROTLI_INLINE void TakeDistanceFromRingBuffer(BrotliDecoderState* s) { + int offset = s->distance_code - 3; + if (s->distance_code <= 3) { + /* Compensate double distance-ring-buffer roll for dictionary items. */ + s->distance_context = 1 >> s->distance_code; + s->distance_code = s->dist_rb[(s->dist_rb_idx - offset) & 3]; + s->dist_rb_idx -= s->distance_context; + } else { + int index_delta = 3; + int delta; + int base = s->distance_code - 10; + if (s->distance_code < 10) { + base = s->distance_code - 4; + } else { + index_delta = 2; + } + /* Unpack one of six 4-bit values. */ + delta = ((0x605142 >> (4 * base)) & 0xF) - 3; + s->distance_code = s->dist_rb[(s->dist_rb_idx + index_delta) & 0x3] + delta; + 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 = 0x7FFFFFFF; + } + } +} + +static BROTLI_INLINE BROTLI_BOOL 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 BROTLI_TRUE; + } +} + +static BROTLI_INLINE BROTLI_BOOL SafeReadBits32( + BrotliBitReader* const br, uint32_t n_bits, uint32_t* val) { + if (n_bits != 0) { + return BrotliSafeReadBits32(br, n_bits, val); + } else { + *val = 0; + return BROTLI_TRUE; + } +} + +/* + RFC 7932 Section 4 with "..." shortenings and "[]" emendations. + + Each distance ... is represented with a pair <distance code, extra bits>... + The distance code is encoded using a prefix code... The number of extra bits + can be 0..24... Two additional parameters: NPOSTFIX (0..3), and ... + NDIRECT (0..120) ... are encoded in the meta-block header... + + The first 16 distance symbols ... reference past distances... ring buffer ... + Next NDIRECT distance symbols ... represent distances from 1 to NDIRECT... + [For] distance symbols 16 + NDIRECT and greater ... the number of extra bits + ... is given by the following formula: + + [ xcode = dcode - NDIRECT - 16 ] + ndistbits = 1 + [ xcode ] >> (NPOSTFIX + 1) + + ... +*/ + +/* + RFC 7932 Section 9.2 with "..." shortenings and "[]" emendations. + + ... to get the actual value of the parameter NDIRECT, left-shift this + four-bit number by NPOSTFIX bits ... +*/ + +/* Remaining formulas from RFC 7932 Section 4 could be rewritten as following: + + alphabet_size = 16 + NDIRECT + (max_distbits << (NPOSTFIX + 1)) + + half = ((xcode >> NPOSTFIX) & 1) << ndistbits + postfix = xcode & ((1 << NPOSTFIX) - 1) + range_start = 2 * (1 << ndistbits - 1 - 1) + + distance = (range_start + half + extra) << NPOSTFIX + postfix + NDIRECT + 1 + + NB: ndistbits >= 1 -> range_start >= 0 + NB: range_start has factor 2, as the range is covered by 2 "halves" + NB: extra -1 offset in range_start formula covers the absence of + ndistbits = 0 case + NB: when NPOSTFIX = 0, NDIRECT is not greater than 15 + + In other words, xcode has the following binary structure - XXXHPPP: + - XXX represent the number of extra distance bits + - H selects upper / lower range of distances + - PPP represent "postfix" + + "Regular" distance encoding has NPOSTFIX = 0; omitting the postfix part + simplifies distance calculation. + + Using NPOSTFIX > 0 allows cheaper encoding of regular structures, e.g. where + most of distances have the same reminder of division by 2/4/8. For example, + the table of int32_t values that come from different sources; if it is likely + that 3 highest bytes of values from the same source are the same, then + copy distance often looks like 4x + y. + + Distance calculation could be rewritten to: + + ndistbits = NDISTBITS(NDIRECT, NPOSTFIX)[dcode] + distance = OFFSET(NDIRECT, NPOSTFIX)[dcode] + extra << NPOSTFIX + + NDISTBITS and OFFSET could be pre-calculated, as NDIRECT and NPOSTFIX could + change only once per meta-block. +*/ + +/* Calculates distance lookup table. + NB: it is possible to have all 64 tables precalculated. */ +static void CalculateDistanceLut(BrotliDecoderState* s) { + BrotliMetablockBodyArena* b = &s->arena.body; + uint32_t npostfix = s->distance_postfix_bits; + uint32_t ndirect = s->num_direct_distance_codes; + uint32_t alphabet_size_limit = s->distance_hgroup.alphabet_size_limit; + uint32_t postfix = 1u << npostfix; + uint32_t j; + uint32_t bits = 1; + uint32_t half = 0; + + /* Skip short codes. */ + uint32_t i = BROTLI_NUM_DISTANCE_SHORT_CODES; + + /* Fill direct codes. */ + for (j = 0; j < ndirect; ++j) { + b->dist_extra_bits[i] = 0; + b->dist_offset[i] = j + 1; + ++i; + } + + /* Fill regular distance codes. */ + while (i < alphabet_size_limit) { + uint32_t base = ndirect + ((((2 + half) << bits) - 4) << npostfix) + 1; + /* Always fill the complete group. */ + for (j = 0; j < postfix; ++j) { + b->dist_extra_bits[i] = (uint8_t)bits; + b->dist_offset[i] = base + j; + ++i; + } + bits = bits + half; + half = half ^ 1; + } +} + +/* Precondition: s->distance_code < 0. */ +static BROTLI_INLINE BROTLI_BOOL ReadDistanceInternal( + int safe, BrotliDecoderState* s, BrotliBitReader* br) { + BrotliMetablockBodyArena* b = &s->arena.body; + uint32_t code; + uint32_t bits; + BrotliBitReaderState memento; + HuffmanCode* distance_tree = s->distance_hgroup.htrees[s->dist_htree_index]; + if (!safe) { + code = ReadSymbol(distance_tree, br); + } else { + BrotliBitReaderSaveState(br, &memento); + if (!SafeReadSymbol(distance_tree, br, &code)) { + return BROTLI_FALSE; + } + } + --s->block_length[2]; + /* Convert the distance code to the actual distance by possibly + looking up past distances from the s->dist_rb. */ + s->distance_context = 0; + if ((code & ~0xFu) == 0) { + s->distance_code = (int)code; + TakeDistanceFromRingBuffer(s); + return BROTLI_TRUE; + } + if (!safe) { + bits = BrotliReadBits32(br, b->dist_extra_bits[code]); + } else { + if (!SafeReadBits32(br, b->dist_extra_bits[code], &bits)) { + ++s->block_length[2]; + BrotliBitReaderRestoreState(br, &memento); + return BROTLI_FALSE; + } + } + s->distance_code = + (int)(b->dist_offset[code] + (bits << s->distance_postfix_bits)); + return BROTLI_TRUE; +} + +static BROTLI_INLINE void ReadDistance( + BrotliDecoderState* s, BrotliBitReader* br) { + ReadDistanceInternal(0, s, br); +} + +static BROTLI_INLINE BROTLI_BOOL SafeReadDistance( + BrotliDecoderState* s, BrotliBitReader* br) { + return ReadDistanceInternal(1, s, br); +} + +static BROTLI_INLINE BROTLI_BOOL ReadCommandInternal( + int safe, BrotliDecoderState* 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 BROTLI_FALSE; + } + } + 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 (BROTLI_PREDICT_FALSE(v.insert_len_extra_bits != 0)) { + insert_len_extra = BrotliReadBits24(br, v.insert_len_extra_bits); + } + copy_length = BrotliReadBits24(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 BROTLI_FALSE; + } + } + s->copy_length = (int)copy_length + v.copy_len_offset; + --s->block_length[1]; + *insert_length += (int)insert_len_extra; + return BROTLI_TRUE; +} + +static BROTLI_INLINE void ReadCommand( + BrotliDecoderState* s, BrotliBitReader* br, int* insert_length) { + ReadCommandInternal(0, s, br, insert_length); +} + +static BROTLI_INLINE BROTLI_BOOL SafeReadCommand( + BrotliDecoderState* s, BrotliBitReader* br, int* insert_length) { + return ReadCommandInternal(1, s, br, insert_length); +} + +static BROTLI_INLINE BROTLI_BOOL CheckInputAmount( + int safe, BrotliBitReader* const br, size_t num) { + if (safe) { + return BROTLI_TRUE; + } + return BrotliCheckInputAmount(br, num); +} + +#define BROTLI_SAFE(METHOD) \ + { \ + if (safe) { \ + if (!Safe##METHOD) { \ + result = BROTLI_DECODER_NEEDS_MORE_INPUT; \ + goto saveStateAndReturn; \ + } \ + } else { \ + METHOD; \ + } \ + } + +static BROTLI_INLINE BrotliDecoderErrorCode ProcessCommandsInternal( + int safe, BrotliDecoderState* s) { + int pos = s->pos; + int i = s->loop_counter; + BrotliDecoderErrorCode result = BROTLI_DECODER_SUCCESS; + BrotliBitReader* br = &s->br; + + if (!CheckInputAmount(safe, br, 28)) { + result = BROTLI_DECODER_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_DECODER_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_DECODER_NEEDS_MORE_INPUT; + goto saveStateAndReturn; + } + if (BROTLI_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_DECODER_NEEDS_MORE_INPUT; + goto saveStateAndReturn; + } + if (BROTLI_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_DECODER_NEEDS_MORE_INPUT; + goto saveStateAndReturn; + } + s->ringbuffer[pos] = (uint8_t)literal; + } + --s->block_length[0]; + BROTLI_LOG_ARRAY_INDEX(s->ringbuffer, pos); + ++pos; + if (BROTLI_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_DECODER_NEEDS_MORE_INPUT; + goto saveStateAndReturn; + } + if (BROTLI_PREDICT_FALSE(s->block_length[0] == 0)) { + BROTLI_SAFE(DecodeLiteralBlockSwitch(s)); + if (s->trivial_literal_context) goto CommandInner; + } + context = BROTLI_CONTEXT(p1, p2, s->context_lookup); + 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_DECODER_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 (BROTLI_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 (BROTLI_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) { + /* Implicit distance case. */ + s->distance_context = s->distance_code ? 0 : 1; + --s->dist_rb_idx; + s->distance_code = s->dist_rb[s->dist_rb_idx & 3]; + } else { + /* Read distance code in the command, unless it was implicitly zero. */ + if (BROTLI_PREDICT_FALSE(s->block_length[2] == 0)) { + BROTLI_SAFE(DecodeDistanceBlockSwitch(s)); + } + BROTLI_SAFE(ReadDistance(s, br)); + } + BROTLI_LOG(("[ProcessCommandsInternal] pos = %d distance = %d\n", + pos, s->distance_code)); + if (s->max_distance != s->max_backward_distance) { + s->max_distance = + (pos < s->max_backward_distance) ? pos : 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) { + /* The maximum allowed distance is BROTLI_MAX_ALLOWED_DISTANCE = 0x7FFFFFFC. + With this choice, no signed overflow can occur after decoding + a special distance code (e.g., after adding 3 to the last distance). */ + if (s->distance_code > BROTLI_MAX_ALLOWED_DISTANCE) { + 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_DECODER_ERROR_FORMAT_DISTANCE); + } + if (i >= BROTLI_MIN_DICTIONARY_WORD_LENGTH && + i <= BROTLI_MAX_DICTIONARY_WORD_LENGTH) { + int address = s->distance_code - s->max_distance - 1; + const BrotliDictionary* words = s->dictionary; + const BrotliTransforms* transforms = s->transforms; + int offset = (int)s->dictionary->offsets_by_length[i]; + uint32_t shift = s->dictionary->size_bits_by_length[i]; + + int mask = (int)BitMask(shift); + int word_idx = address & mask; + int transform_idx = address >> shift; + /* Compensate double distance-ring-buffer roll. */ + s->dist_rb_idx += s->distance_context; + offset += word_idx * i; + if (BROTLI_PREDICT_FALSE(!words->data)) { + return BROTLI_FAILURE(BROTLI_DECODER_ERROR_DICTIONARY_NOT_SET); + } + if (transform_idx < (int)transforms->num_transforms) { + const uint8_t* word = &words->data[offset]; + int len = i; + if (transform_idx == transforms->cutOffTransforms[0]) { + memcpy(&s->ringbuffer[pos], word, (size_t)len); + BROTLI_LOG(("[ProcessCommandsInternal] dictionary word: [%.*s]\n", + len, word)); + } else { + len = BrotliTransformDictionaryWord(&s->ringbuffer[pos], word, len, + transforms, transform_idx); + BROTLI_LOG(("[ProcessCommandsInternal] dictionary word: [%.*s]," + " transform_idx = %d, transformed: [%.*s]\n", + i, word, transform_idx, len, &s->ringbuffer[pos])); + } + pos += len; + s->meta_block_remaining_len -= len; + if (pos >= 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_DECODER_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_DECODER_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 ring-buffer allocation. + Also, we have 16 short codes, that make these 16 bytes irrelevant + in the ring-buffer. 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 (BROTLI_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 BrotliDecoderErrorCode ProcessCommands( + BrotliDecoderState* s) { + return ProcessCommandsInternal(0, s); +} + +static BROTLI_NOINLINE BrotliDecoderErrorCode SafeProcessCommands( + BrotliDecoderState* s) { + return ProcessCommandsInternal(1, s); +} + +BrotliDecoderResult BrotliDecoderDecompress( + size_t encoded_size, const uint8_t* encoded_buffer, size_t* decoded_size, + uint8_t* decoded_buffer) { + BrotliDecoderState s; + BrotliDecoderResult 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; + if (!BrotliDecoderStateInit(&s, 0, 0, 0)) { + return BROTLI_DECODER_RESULT_ERROR; + } + result = BrotliDecoderDecompressStream( + &s, &available_in, &next_in, &available_out, &next_out, &total_out); + *decoded_size = total_out; + BrotliDecoderStateCleanup(&s); + if (result != BROTLI_DECODER_RESULT_SUCCESS) { + result = BROTLI_DECODER_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 least 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 held on enter */ +BrotliDecoderResult BrotliDecoderDecompressStream( + BrotliDecoderState* s, size_t* available_in, const uint8_t** next_in, + size_t* available_out, uint8_t** next_out, size_t* total_out) { + BrotliDecoderErrorCode result = BROTLI_DECODER_SUCCESS; + BrotliBitReader* br = &s->br; + /* Ensure that |total_out| is set, even if no data will ever be pushed out. */ + if (total_out) { + *total_out = s->partial_pos_out; + } + /* Do not try to process further in a case of unrecoverable error. */ + if ((int)s->error_code < 0) { + return BROTLI_DECODER_RESULT_ERROR; + } + if (*available_out && (!next_out || !*next_out)) { + return SaveErrorCode( + s, BROTLI_FAILURE(BROTLI_DECODER_ERROR_INVALID_ARGUMENTS)); + } + if (!*available_out) next_out = 0; + 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_DECODER_NEEDS_MORE_INPUT; + br->next_in = &s->buffer.u8[0]; + } + /* State machine */ + for (;;) { + if (result != BROTLI_DECODER_SUCCESS) { + /* Error, needs more input/output. */ + if (result == BROTLI_DECODER_NEEDS_MORE_INPUT) { + if (s->ringbuffer != 0) { /* Pro-actively push output. */ + BrotliDecoderErrorCode intermediate_result = WriteRingBuffer(s, + available_out, next_out, total_out, BROTLI_TRUE); + /* WriteRingBuffer checks s->meta_block_remaining_len validity. */ + if ((int)intermediate_result < 0) { + result = intermediate_result; + break; + } + } + if (s->buffer_length != 0) { /* Used with internal buffer. */ + if (br->avail_in == 0) { + /* Successfully finished read transaction. + Accumulator 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_DECODER_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_DECODER_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 accumulator, so it is safe to + return unused accumulator 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_DECODER_NEEDS_MORE_INPUT; + break; + } + /* Decode window size. */ + result = DecodeWindowBits(s, br); /* Reads 1..8 bits. */ + if (result != BROTLI_DECODER_SUCCESS) { + break; + } + if (s->large_window) { + s->state = BROTLI_STATE_LARGE_WINDOW_BITS; + break; + } + s->state = BROTLI_STATE_INITIALIZE; + break; + + case BROTLI_STATE_LARGE_WINDOW_BITS: + if (!BrotliSafeReadBits(br, 6, &s->window_bits)) { + result = BROTLI_DECODER_NEEDS_MORE_INPUT; + break; + } + if (s->window_bits < BROTLI_LARGE_MIN_WBITS || + s->window_bits > BROTLI_LARGE_MAX_WBITS) { + result = BROTLI_FAILURE(BROTLI_DECODER_ERROR_FORMAT_WINDOW_BITS); + break; + } + s->state = BROTLI_STATE_INITIALIZE; + /* Fall through. */ + + case BROTLI_STATE_INITIALIZE: + BROTLI_LOG_UINT(s->window_bits); + /* Maximum distance, see section 9.1. of the spec. */ + s->max_backward_distance = (1 << s->window_bits) - BROTLI_WINDOW_GAP; + + /* Allocate memory for both block_type_trees and block_len_trees. */ + s->block_type_trees = (HuffmanCode*)BROTLI_DECODER_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_DECODER_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; + /* Fall through. */ + + case BROTLI_STATE_METABLOCK_BEGIN: + BrotliDecoderStateMetablockBegin(s); + BROTLI_LOG_UINT(s->pos); + s->state = BROTLI_STATE_METABLOCK_HEADER; + /* Fall through. */ + + case BROTLI_STATE_METABLOCK_HEADER: + result = DecodeMetaBlockLength(s, br); /* Reads 2 - 31 bits. */ + if (result != BROTLI_DECODER_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_DECODER_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; + } + BrotliCalculateRingBufferSize(s); + if (s->is_uncompressed) { + s->state = BROTLI_STATE_UNCOMPRESSED; + break; + } + s->state = BROTLI_STATE_BEFORE_COMPRESSED_METABLOCK_HEADER; + /* Fall through. */ + + case BROTLI_STATE_BEFORE_COMPRESSED_METABLOCK_HEADER: { + BrotliMetablockHeaderArena* h = &s->arena.header; + s->loop_counter = 0; + /* Initialize compressed metablock header arena. */ + h->sub_loop_counter = 0; + /* Make small negative indexes addressable. */ + h->symbol_lists = + &h->symbols_lists_array[BROTLI_HUFFMAN_MAX_CODE_LENGTH + 1]; + h->substate_huffman = BROTLI_STATE_HUFFMAN_NONE; + h->substate_tree_group = BROTLI_STATE_TREE_GROUP_NONE; + h->substate_context_map = BROTLI_STATE_CONTEXT_MAP_NONE; + s->state = BROTLI_STATE_HUFFMAN_CODE_0; + } + /* Fall through. */ + + 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_DECODER_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; + /* Fall through. */ + + case BROTLI_STATE_HUFFMAN_CODE_1: { + uint32_t alphabet_size = s->num_block_types[s->loop_counter] + 2; + int tree_offset = s->loop_counter * BROTLI_HUFFMAN_MAX_SIZE_258; + result = ReadHuffmanCode(alphabet_size, alphabet_size, + &s->block_type_trees[tree_offset], NULL, s); + if (result != BROTLI_DECODER_SUCCESS) break; + s->state = BROTLI_STATE_HUFFMAN_CODE_2; + } + /* Fall through. */ + + case BROTLI_STATE_HUFFMAN_CODE_2: { + uint32_t alphabet_size = BROTLI_NUM_BLOCK_LEN_SYMBOLS; + int tree_offset = s->loop_counter * BROTLI_HUFFMAN_MAX_SIZE_26; + result = ReadHuffmanCode(alphabet_size, alphabet_size, + &s->block_len_trees[tree_offset], NULL, s); + if (result != BROTLI_DECODER_SUCCESS) break; + s->state = BROTLI_STATE_HUFFMAN_CODE_3; + } + /* Fall through. */ + + 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_DECODER_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_UNCOMPRESSED: { + result = CopyUncompressedBlockToOutput( + available_out, next_out, total_out, s); + if (result != BROTLI_DECODER_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_DECODER_NEEDS_MORE_INPUT; + break; + } + } + if (result == BROTLI_DECODER_SUCCESS) { + s->state = BROTLI_STATE_METABLOCK_DONE; + } + break; + + case BROTLI_STATE_METABLOCK_HEADER_2: { + uint32_t bits; + if (!BrotliSafeReadBits(br, 6, &bits)) { + result = BROTLI_DECODER_NEEDS_MORE_INPUT; + break; + } + s->distance_postfix_bits = bits & BitMask(2); + bits >>= 2; + s->num_direct_distance_codes = bits << s->distance_postfix_bits; + BROTLI_LOG_UINT(s->num_direct_distance_codes); + BROTLI_LOG_UINT(s->distance_postfix_bits); + s->context_modes = + (uint8_t*)BROTLI_DECODER_ALLOC(s, (size_t)s->num_block_types[0]); + if (s->context_modes == 0) { + result = BROTLI_FAILURE(BROTLI_DECODER_ERROR_ALLOC_CONTEXT_MODES); + break; + } + s->loop_counter = 0; + s->state = BROTLI_STATE_CONTEXT_MODES; + } + /* Fall through. */ + + case BROTLI_STATE_CONTEXT_MODES: + result = ReadContextModes(s); + if (result != BROTLI_DECODER_SUCCESS) { + break; + } + s->state = BROTLI_STATE_CONTEXT_MAP_1; + /* Fall through. */ + + case BROTLI_STATE_CONTEXT_MAP_1: + result = DecodeContextMap( + s->num_block_types[0] << BROTLI_LITERAL_CONTEXT_BITS, + &s->num_literal_htrees, &s->context_map, s); + if (result != BROTLI_DECODER_SUCCESS) { + break; + } + DetectTrivialLiteralBlockTypes(s); + s->state = BROTLI_STATE_CONTEXT_MAP_2; + /* Fall through. */ + + case BROTLI_STATE_CONTEXT_MAP_2: { + uint32_t npostfix = s->distance_postfix_bits; + uint32_t ndirect = s->num_direct_distance_codes; + uint32_t distance_alphabet_size_max = BROTLI_DISTANCE_ALPHABET_SIZE( + npostfix, ndirect, BROTLI_MAX_DISTANCE_BITS); + uint32_t distance_alphabet_size_limit = distance_alphabet_size_max; + BROTLI_BOOL allocation_success = BROTLI_TRUE; + if (s->large_window) { + BrotliDistanceCodeLimit limit = BrotliCalculateDistanceCodeLimit( + BROTLI_MAX_ALLOWED_DISTANCE, npostfix, ndirect); + distance_alphabet_size_max = BROTLI_DISTANCE_ALPHABET_SIZE( + npostfix, ndirect, BROTLI_LARGE_MAX_DISTANCE_BITS); + distance_alphabet_size_limit = limit.max_alphabet_size; + } + result = DecodeContextMap( + s->num_block_types[2] << BROTLI_DISTANCE_CONTEXT_BITS, + &s->num_dist_htrees, &s->dist_context_map, s); + if (result != BROTLI_DECODER_SUCCESS) { + break; + } + allocation_success &= BrotliDecoderHuffmanTreeGroupInit( + s, &s->literal_hgroup, BROTLI_NUM_LITERAL_SYMBOLS, + BROTLI_NUM_LITERAL_SYMBOLS, s->num_literal_htrees); + allocation_success &= BrotliDecoderHuffmanTreeGroupInit( + s, &s->insert_copy_hgroup, BROTLI_NUM_COMMAND_SYMBOLS, + BROTLI_NUM_COMMAND_SYMBOLS, s->num_block_types[1]); + allocation_success &= BrotliDecoderHuffmanTreeGroupInit( + s, &s->distance_hgroup, distance_alphabet_size_max, + distance_alphabet_size_limit, s->num_dist_htrees); + if (!allocation_success) { + return SaveErrorCode(s, + BROTLI_FAILURE(BROTLI_DECODER_ERROR_ALLOC_TREE_GROUPS)); + } + s->loop_counter = 0; + s->state = BROTLI_STATE_TREE_GROUP; + } + /* Fall through. */ + + 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_DECODER_ERROR_UNREACHABLE)); + } + result = HuffmanTreeGroupDecode(hgroup, s); + if (result != BROTLI_DECODER_SUCCESS) break; + s->loop_counter++; + if (s->loop_counter < 3) { + break; + } + s->state = BROTLI_STATE_BEFORE_COMPRESSED_METABLOCK_BODY; + } + /* Fall through. */ + + case BROTLI_STATE_BEFORE_COMPRESSED_METABLOCK_BODY: + PrepareLiteralDecoding(s); + s->dist_context_map_slice = s->dist_context_map; + s->htree_command = s->insert_copy_hgroup.htrees[0]; + if (!BrotliEnsureRingBuffer(s)) { + result = BROTLI_FAILURE(BROTLI_DECODER_ERROR_ALLOC_RING_BUFFER_2); + break; + } + CalculateDistanceLut(s); + s->state = BROTLI_STATE_COMMAND_BEGIN; + /* Fall through. */ + + case BROTLI_STATE_COMMAND_BEGIN: + /* Fall through. */ + case BROTLI_STATE_COMMAND_INNER: + /* Fall through. */ + case BROTLI_STATE_COMMAND_POST_DECODE_LITERALS: + /* Fall through. */ + case BROTLI_STATE_COMMAND_POST_WRAP_COPY: + result = ProcessCommands(s); + if (result == BROTLI_DECODER_NEEDS_MORE_INPUT) { + result = SafeProcessCommands(s); + } + break; + + case BROTLI_STATE_COMMAND_INNER_WRITE: + /* Fall through. */ + case BROTLI_STATE_COMMAND_POST_WRITE_1: + /* Fall through. */ + case BROTLI_STATE_COMMAND_POST_WRITE_2: + result = WriteRingBuffer( + s, available_out, next_out, total_out, BROTLI_FALSE); + if (result != BROTLI_DECODER_SUCCESS) { + break; + } + WrapRingBuffer(s); + if (s->ringbuffer_size == 1 << s->window_bits) { + s->max_distance = s->max_backward_distance; + } + if (s->state == BROTLI_STATE_COMMAND_POST_WRITE_1) { + 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_DECODER_ERROR_FORMAT_BLOCK_LENGTH_2); + break; + } + BrotliDecoderStateCleanupAfterMetablock(s); + if (!s->is_last_metablock) { + s->state = BROTLI_STATE_METABLOCK_BEGIN; + break; + } + if (!BrotliJumpToByteBoundary(br)) { + result = BROTLI_FAILURE(BROTLI_DECODER_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; + /* Fall through. */ + + case BROTLI_STATE_DONE: + if (s->ringbuffer != 0) { + result = WriteRingBuffer( + s, available_out, next_out, total_out, BROTLI_TRUE); + if (result != BROTLI_DECODER_SUCCESS) { + break; + } + } + return SaveErrorCode(s, result); + } + } + return SaveErrorCode(s, result); +} + +BROTLI_BOOL BrotliDecoderHasMoreOutput(const BrotliDecoderState* s) { + /* After unrecoverable error remaining output is considered nonsensical. */ + if ((int)s->error_code < 0) { + return BROTLI_FALSE; + } + return TO_BROTLI_BOOL( + s->ringbuffer != 0 && UnwrittenBytes(s, BROTLI_FALSE) != 0); +} + +const uint8_t* BrotliDecoderTakeOutput(BrotliDecoderState* s, size_t* size) { + uint8_t* result = 0; + size_t available_out = *size ? *size : 1u << 24; + size_t requested_out = available_out; + BrotliDecoderErrorCode status; + if ((s->ringbuffer == 0) || ((int)s->error_code < 0)) { + *size = 0; + return 0; + } + WrapRingBuffer(s); + status = WriteRingBuffer(s, &available_out, &result, 0, BROTLI_TRUE); + /* Either WriteRingBuffer returns those "success" codes... */ + if (status == BROTLI_DECODER_SUCCESS || + status == BROTLI_DECODER_NEEDS_MORE_OUTPUT) { + *size = requested_out - available_out; + } else { + /* ... or stream is broken. Normally this should be caught by + BrotliDecoderDecompressStream, this is just a safeguard. */ + if ((int)status < 0) SaveErrorCode(s, status); + *size = 0; + result = 0; + } + return result; +} + +BROTLI_BOOL BrotliDecoderIsUsed(const BrotliDecoderState* s) { + return TO_BROTLI_BOOL(s->state != BROTLI_STATE_UNINITED || + BrotliGetAvailableBits(&s->br) != 0); +} + +BROTLI_BOOL BrotliDecoderIsFinished(const BrotliDecoderState* s) { + return TO_BROTLI_BOOL(s->state == BROTLI_STATE_DONE) && + !BrotliDecoderHasMoreOutput(s); +} + +BrotliDecoderErrorCode BrotliDecoderGetErrorCode(const BrotliDecoderState* s) { + return (BrotliDecoderErrorCode)s->error_code; +} + +const char* BrotliDecoderErrorString(BrotliDecoderErrorCode c) { + switch (c) { +#define BROTLI_ERROR_CODE_CASE_(PREFIX, NAME, CODE) \ + case BROTLI_DECODER ## PREFIX ## NAME: return #NAME; +#define BROTLI_NOTHING_ + BROTLI_DECODER_ERROR_CODES_LIST(BROTLI_ERROR_CODE_CASE_, BROTLI_NOTHING_) +#undef BROTLI_ERROR_CODE_CASE_ +#undef BROTLI_NOTHING_ + default: return "INVALID"; + } +} + +uint32_t BrotliDecoderVersion() { + return BROTLI_VERSION; +} + +#if defined(__cplusplus) || defined(c_plusplus) +} /* extern "C" */ +#endif |