diff options
Diffstat (limited to 'modules/brotli/dec/bit_reader.c')
| -rw-r--r-- | modules/brotli/dec/bit_reader.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/modules/brotli/dec/bit_reader.c b/modules/brotli/dec/bit_reader.c index 722fd906d..7f7b256a4 100644 --- a/modules/brotli/dec/bit_reader.c +++ b/modules/brotli/dec/bit_reader.c @@ -15,6 +15,17 @@ extern "C" { #endif +const uint32_t kBrotliBitMask[33] = { 0x00000000, + 0x00000001, 0x00000003, 0x00000007, 0x0000000F, + 0x0000001F, 0x0000003F, 0x0000007F, 0x000000FF, + 0x000001FF, 0x000003FF, 0x000007FF, 0x00000FFF, + 0x00001FFF, 0x00003FFF, 0x00007FFF, 0x0000FFFF, + 0x0001FFFF, 0x0003FFFF, 0x0007FFFF, 0x000FFFFF, + 0x001FFFFF, 0x003FFFFF, 0x007FFFFF, 0x00FFFFFF, + 0x01FFFFFF, 0x03FFFFFF, 0x07FFFFFF, 0x0FFFFFFF, + 0x1FFFFFFF, 0x3FFFFFFF, 0x7FFFFFFF, 0xFFFFFFFF +}; + void BrotliInitBitReader(BrotliBitReader* const br) { br->val_ = 0; br->bit_pos_ = sizeof(br->val_) << 3; @@ -43,6 +54,23 @@ BROTLI_BOOL BrotliWarmupBitReader(BrotliBitReader* const br) { return BROTLI_TRUE; } +BROTLI_BOOL BrotliSafeReadBits32Slow(BrotliBitReader* const br, + uint32_t n_bits, uint32_t* val) { + uint32_t low_val; + uint32_t high_val; + BrotliBitReaderState memento; + BROTLI_DCHECK(n_bits <= 32); + BROTLI_DCHECK(n_bits > 24); + BrotliBitReaderSaveState(br, &memento); + if (!BrotliSafeReadBits(br, 16, &low_val) || + !BrotliSafeReadBits(br, n_bits - 16, &high_val)) { + BrotliBitReaderRestoreState(br, &memento); + return BROTLI_FALSE; + } + *val = low_val | (high_val << 16); + return BROTLI_TRUE; +} + #if defined(__cplusplus) || defined(c_plusplus) } /* extern "C" */ #endif |