diff options
Diffstat (limited to 'deps/node/deps/brotli/c/dec/bit_reader.h')
| -rw-r--r-- | deps/node/deps/brotli/c/dec/bit_reader.h | 309 |
1 files changed, 0 insertions, 309 deletions
diff --git a/deps/node/deps/brotli/c/dec/bit_reader.h b/deps/node/deps/brotli/c/dec/bit_reader.h deleted file mode 100644 index c06e9141..00000000 --- a/deps/node/deps/brotli/c/dec/bit_reader.h +++ /dev/null @@ -1,309 +0,0 @@ -/* Copyright 2013 Google Inc. All Rights Reserved. - - Distributed under MIT license. - See file LICENSE for detail or copy at https://opensource.org/licenses/MIT -*/ - -/* Bit reading helpers */ - -#ifndef BROTLI_DEC_BIT_READER_H_ -#define BROTLI_DEC_BIT_READER_H_ - -#include <string.h> /* memcpy */ - -#include "../common/platform.h" -#include <brotli/types.h> - -#if defined(__cplusplus) || defined(c_plusplus) -extern "C" { -#endif - -#define BROTLI_SHORT_FILL_BIT_WINDOW_READ (sizeof(brotli_reg_t) >> 1) - -static const uint32_t kBitMask[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 -}; - -static BROTLI_INLINE uint32_t BitMask(uint32_t n) { - if (BROTLI_IS_CONSTANT(n) || BROTLI_HAS_UBFX) { - /* Masking with this expression turns to a single - "Unsigned Bit Field Extract" UBFX instruction on ARM. */ - return ~((0xFFFFFFFFu) << n); - } else { - return kBitMask[n]; - } -} - -typedef struct { - brotli_reg_t val_; /* pre-fetched bits */ - uint32_t bit_pos_; /* current bit-reading position in val_ */ - const uint8_t* next_in; /* the byte we're reading from */ - size_t avail_in; -} BrotliBitReader; - -typedef struct { - brotli_reg_t val_; - uint32_t bit_pos_; - const uint8_t* next_in; - size_t avail_in; -} BrotliBitReaderState; - -/* Initializes the BrotliBitReader fields. */ -BROTLI_INTERNAL void BrotliInitBitReader(BrotliBitReader* const br); - -/* Ensures that accumulator is not empty. - May consume up to sizeof(brotli_reg_t) - 1 bytes of input. - Returns BROTLI_FALSE if data is required but there is no input available. - For BROTLI_ALIGNED_READ this function also prepares bit reader for aligned - reading. */ -BROTLI_INTERNAL BROTLI_BOOL BrotliWarmupBitReader(BrotliBitReader* const br); - -static BROTLI_INLINE void BrotliBitReaderSaveState( - BrotliBitReader* const from, BrotliBitReaderState* to) { - to->val_ = from->val_; - to->bit_pos_ = from->bit_pos_; - to->next_in = from->next_in; - to->avail_in = from->avail_in; -} - -static BROTLI_INLINE void BrotliBitReaderRestoreState( - BrotliBitReader* const to, BrotliBitReaderState* from) { - to->val_ = from->val_; - to->bit_pos_ = from->bit_pos_; - to->next_in = from->next_in; - to->avail_in = from->avail_in; -} - -static BROTLI_INLINE uint32_t BrotliGetAvailableBits( - const BrotliBitReader* br) { - return (BROTLI_64_BITS ? 64 : 32) - br->bit_pos_; -} - -/* Returns amount of unread bytes the bit reader still has buffered from the - BrotliInput, including whole bytes in br->val_. */ -static BROTLI_INLINE size_t BrotliGetRemainingBytes(BrotliBitReader* br) { - return br->avail_in + (BrotliGetAvailableBits(br) >> 3); -} - -/* Checks if there is at least |num| bytes left in the input ring-buffer - (excluding the bits remaining in br->val_). */ -static BROTLI_INLINE BROTLI_BOOL BrotliCheckInputAmount( - BrotliBitReader* const br, size_t num) { - return TO_BROTLI_BOOL(br->avail_in >= num); -} - -/* Guarantees that there are at least |n_bits| + 1 bits in accumulator. - Precondition: accumulator contains at least 1 bit. - |n_bits| should be in the range [1..24] for regular build. For portable - non-64-bit little-endian build only 16 bits are safe to request. */ -static BROTLI_INLINE void BrotliFillBitWindow( - BrotliBitReader* const br, uint32_t n_bits) { -#if (BROTLI_64_BITS) - if (!BROTLI_ALIGNED_READ && BROTLI_IS_CONSTANT(n_bits) && (n_bits <= 8)) { - if (br->bit_pos_ >= 56) { - br->val_ >>= 56; - br->bit_pos_ ^= 56; /* here same as -= 56 because of the if condition */ - br->val_ |= BROTLI_UNALIGNED_LOAD64LE(br->next_in) << 8; - br->avail_in -= 7; - br->next_in += 7; - } - } else if ( - !BROTLI_ALIGNED_READ && BROTLI_IS_CONSTANT(n_bits) && (n_bits <= 16)) { - if (br->bit_pos_ >= 48) { - br->val_ >>= 48; - br->bit_pos_ ^= 48; /* here same as -= 48 because of the if condition */ - br->val_ |= BROTLI_UNALIGNED_LOAD64LE(br->next_in) << 16; - br->avail_in -= 6; - br->next_in += 6; - } - } else { - if (br->bit_pos_ >= 32) { - br->val_ >>= 32; - br->bit_pos_ ^= 32; /* here same as -= 32 because of the if condition */ - br->val_ |= ((uint64_t)BROTLI_UNALIGNED_LOAD32LE(br->next_in)) << 32; - br->avail_in -= BROTLI_SHORT_FILL_BIT_WINDOW_READ; - br->next_in += BROTLI_SHORT_FILL_BIT_WINDOW_READ; - } - } -#else - if (!BROTLI_ALIGNED_READ && BROTLI_IS_CONSTANT(n_bits) && (n_bits <= 8)) { - if (br->bit_pos_ >= 24) { - br->val_ >>= 24; - br->bit_pos_ ^= 24; /* here same as -= 24 because of the if condition */ - br->val_ |= BROTLI_UNALIGNED_LOAD32LE(br->next_in) << 8; - br->avail_in -= 3; - br->next_in += 3; - } - } else { - if (br->bit_pos_ >= 16) { - br->val_ >>= 16; - br->bit_pos_ ^= 16; /* here same as -= 16 because of the if condition */ - br->val_ |= ((uint32_t)BROTLI_UNALIGNED_LOAD16LE(br->next_in)) << 16; - br->avail_in -= BROTLI_SHORT_FILL_BIT_WINDOW_READ; - br->next_in += BROTLI_SHORT_FILL_BIT_WINDOW_READ; - } - } -#endif -} - -/* Mostly like BrotliFillBitWindow, but guarantees only 16 bits and reads no - more than BROTLI_SHORT_FILL_BIT_WINDOW_READ bytes of input. */ -static BROTLI_INLINE void BrotliFillBitWindow16(BrotliBitReader* const br) { - BrotliFillBitWindow(br, 17); -} - -/* Tries to pull one byte of input to accumulator. - Returns BROTLI_FALSE if there is no input available. */ -static BROTLI_INLINE BROTLI_BOOL BrotliPullByte(BrotliBitReader* const br) { - if (br->avail_in == 0) { - return BROTLI_FALSE; - } - br->val_ >>= 8; -#if (BROTLI_64_BITS) - br->val_ |= ((uint64_t)*br->next_in) << 56; -#else - br->val_ |= ((uint32_t)*br->next_in) << 24; -#endif - br->bit_pos_ -= 8; - --br->avail_in; - ++br->next_in; - return BROTLI_TRUE; -} - -/* Returns currently available bits. - The number of valid bits could be calculated by BrotliGetAvailableBits. */ -static BROTLI_INLINE brotli_reg_t BrotliGetBitsUnmasked( - BrotliBitReader* const br) { - return br->val_ >> br->bit_pos_; -} - -/* Like BrotliGetBits, but does not mask the result. - The result contains at least 16 valid bits. */ -static BROTLI_INLINE uint32_t BrotliGet16BitsUnmasked( - BrotliBitReader* const br) { - BrotliFillBitWindow(br, 16); - return (uint32_t)BrotliGetBitsUnmasked(br); -} - -/* Returns the specified number of bits from |br| without advancing bit - position. */ -static BROTLI_INLINE uint32_t BrotliGetBits( - BrotliBitReader* const br, uint32_t n_bits) { - BrotliFillBitWindow(br, n_bits); - return (uint32_t)BrotliGetBitsUnmasked(br) & BitMask(n_bits); -} - -/* Tries to peek the specified amount of bits. Returns BROTLI_FALSE, if there - is not enough input. */ -static BROTLI_INLINE BROTLI_BOOL BrotliSafeGetBits( - BrotliBitReader* const br, uint32_t n_bits, uint32_t* val) { - while (BrotliGetAvailableBits(br) < n_bits) { - if (!BrotliPullByte(br)) { - return BROTLI_FALSE; - } - } - *val = (uint32_t)BrotliGetBitsUnmasked(br) & BitMask(n_bits); - return BROTLI_TRUE; -} - -/* Advances the bit pos by |n_bits|. */ -static BROTLI_INLINE void BrotliDropBits( - BrotliBitReader* const br, uint32_t n_bits) { - br->bit_pos_ += n_bits; -} - -static BROTLI_INLINE void BrotliBitReaderUnload(BrotliBitReader* br) { - uint32_t unused_bytes = BrotliGetAvailableBits(br) >> 3; - uint32_t unused_bits = unused_bytes << 3; - br->avail_in += unused_bytes; - br->next_in -= unused_bytes; - if (unused_bits == sizeof(br->val_) << 3) { - br->val_ = 0; - } else { - br->val_ <<= unused_bits; - } - br->bit_pos_ += unused_bits; -} - -/* Reads the specified number of bits from |br| and advances the bit pos. - Precondition: accumulator MUST contain at least |n_bits|. */ -static BROTLI_INLINE void BrotliTakeBits( - BrotliBitReader* const br, uint32_t n_bits, uint32_t* val) { - *val = (uint32_t)BrotliGetBitsUnmasked(br) & BitMask(n_bits); - BROTLI_LOG(("[BrotliReadBits] %d %d %d val: %6x\n", - (int)br->avail_in, (int)br->bit_pos_, (int)n_bits, (int)*val)); - BrotliDropBits(br, n_bits); -} - -/* Reads the specified number of bits from |br| and advances the bit pos. - Assumes that there is enough input to perform BrotliFillBitWindow. */ -static BROTLI_INLINE uint32_t BrotliReadBits( - BrotliBitReader* const br, uint32_t n_bits) { - if (BROTLI_64_BITS || (n_bits <= 16)) { - uint32_t val; - BrotliFillBitWindow(br, n_bits); - BrotliTakeBits(br, n_bits, &val); - return val; - } else { - uint32_t low_val; - uint32_t high_val; - BrotliFillBitWindow(br, 16); - BrotliTakeBits(br, 16, &low_val); - BrotliFillBitWindow(br, 8); - BrotliTakeBits(br, n_bits - 16, &high_val); - return low_val | (high_val << 16); - } -} - -/* Tries to read the specified amount of bits. Returns BROTLI_FALSE, if there - is not enough input. |n_bits| MUST be positive. */ -static BROTLI_INLINE BROTLI_BOOL BrotliSafeReadBits( - BrotliBitReader* const br, uint32_t n_bits, uint32_t* val) { - while (BrotliGetAvailableBits(br) < n_bits) { - if (!BrotliPullByte(br)) { - return BROTLI_FALSE; - } - } - BrotliTakeBits(br, n_bits, val); - return BROTLI_TRUE; -} - -/* Advances the bit reader position to the next byte boundary and verifies - that any skipped bits are set to zero. */ -static BROTLI_INLINE BROTLI_BOOL BrotliJumpToByteBoundary(BrotliBitReader* br) { - uint32_t pad_bits_count = BrotliGetAvailableBits(br) & 0x7; - uint32_t pad_bits = 0; - if (pad_bits_count != 0) { - BrotliTakeBits(br, pad_bits_count, &pad_bits); - } - return TO_BROTLI_BOOL(pad_bits == 0); -} - -/* Copies remaining input bytes stored in the bit reader to the output. Value - |num| may not be larger than BrotliGetRemainingBytes. The bit reader must be - warmed up again after this. */ -static BROTLI_INLINE void BrotliCopyBytes(uint8_t* dest, - BrotliBitReader* br, size_t num) { - while (BrotliGetAvailableBits(br) >= 8 && num > 0) { - *dest = (uint8_t)BrotliGetBitsUnmasked(br); - BrotliDropBits(br, 8); - ++dest; - --num; - } - memcpy(dest, br->next_in, num); - br->avail_in -= num; - br->next_in += num; -} - -#if defined(__cplusplus) || defined(c_plusplus) -} /* extern "C" */ -#endif - -#endif /* BROTLI_DEC_BIT_READER_H_ */ |