diff options
Diffstat (limited to 'drivers/webp/utils/bit_writer.h')
| -rw-r--r-- | drivers/webp/utils/bit_writer.h | 106 |
1 files changed, 64 insertions, 42 deletions
diff --git a/drivers/webp/utils/bit_writer.h b/drivers/webp/utils/bit_writer.h index 57f39b11b1..867a5ee055 100644 --- a/drivers/webp/utils/bit_writer.h +++ b/drivers/webp/utils/bit_writer.h @@ -1,8 +1,10 @@ // Copyright 2011 Google Inc. All Rights Reserved. // -// This code is licensed under the same terms as WebM: -// Software License Agreement: http://www.webmproject.org/license/software/ -// Additional IP Rights Grant: http://www.webmproject.org/license/additional/ +// Use of this source code is governed by a BSD-style license +// that can be found in the COPYING file in the root of the source +// tree. An additional intellectual property rights grant can be found +// in the file PATENTS. All contributing project authors may +// be found in the AUTHORS file in the root of the source tree. // ----------------------------------------------------------------------------- // // Bit writing and boolean coder @@ -12,9 +14,9 @@ #ifndef WEBP_UTILS_BIT_WRITER_H_ #define WEBP_UTILS_BIT_WRITER_H_ -#include "../types.h" +#include "webp/types.h" -#if defined(__cplusplus) || defined(c_plusplus) +#ifdef __cplusplus extern "C" { #endif @@ -43,8 +45,8 @@ void VP8BitWriterWipeOut(VP8BitWriter* const bw); int VP8PutBit(VP8BitWriter* const bw, int bit, int prob); int VP8PutBitUniform(VP8BitWriter* const bw, int bit); -void VP8PutValue(VP8BitWriter* const bw, int value, int nb_bits); -void VP8PutSignedValue(VP8BitWriter* const bw, int value, int nb_bits); +void VP8PutBits(VP8BitWriter* const bw, uint32_t value, int nb_bits); +void VP8PutSignedBits(VP8BitWriter* const bw, int value, int nb_bits); // Appends some bytes to the internal buffer. Data is copied. int VP8BitWriterAppend(VP8BitWriter* const bw, @@ -66,57 +68,77 @@ static WEBP_INLINE size_t VP8BitWriterSize(const VP8BitWriter* const bw) { //------------------------------------------------------------------------------ // VP8LBitWriter -// TODO(vikasa): VP8LBitWriter is copied as-is from lossless code. There's scope -// of re-using VP8BitWriter. Will evaluate once basic lossless encoder is -// implemented. -typedef struct { - uint8_t* buf_; - size_t bit_pos_; - size_t max_bytes_; +#if defined(__x86_64__) || defined(_M_X64) // 64bit +typedef uint64_t vp8l_atype_t; // accumulator type +typedef uint32_t vp8l_wtype_t; // writing type +#define WSWAP HToLE32 +#define VP8L_WRITER_BYTES 4 // sizeof(vp8l_wtype_t) +#define VP8L_WRITER_BITS 32 // 8 * sizeof(vp8l_wtype_t) +#define VP8L_WRITER_MAX_BITS 64 // 8 * sizeof(vp8l_atype_t) +#else +typedef uint32_t vp8l_atype_t; +typedef uint16_t vp8l_wtype_t; +#define WSWAP HToLE16 +#define VP8L_WRITER_BYTES 2 +#define VP8L_WRITER_BITS 16 +#define VP8L_WRITER_MAX_BITS 32 +#endif - // After all bits are written, the caller must observe the state of - // error_. A value of 1 indicates that a memory allocation failure - // has happened during bit writing. A value of 0 indicates successful +typedef struct { + vp8l_atype_t bits_; // bit accumulator + int used_; // number of bits used in accumulator + uint8_t* buf_; // start of buffer + uint8_t* cur_; // current write position + uint8_t* end_; // end of buffer + + // After all bits are written (VP8LBitWriterFinish()), the caller must observe + // the state of error_. A value of 1 indicates that a memory allocation + // failure has happened during bit writing. A value of 0 indicates successful // writing of bits. int error_; } VP8LBitWriter; static WEBP_INLINE size_t VP8LBitWriterNumBytes(VP8LBitWriter* const bw) { - return (bw->bit_pos_ + 7) >> 3; -} - -static WEBP_INLINE uint8_t* VP8LBitWriterFinish(VP8LBitWriter* const bw) { - return bw->buf_; + return (bw->cur_ - bw->buf_) + ((bw->used_ + 7) >> 3); } -// Returns 0 in case of memory allocation error. +// Returns false in case of memory allocation error. int VP8LBitWriterInit(VP8LBitWriter* const bw, size_t expected_size); +// Finalize the bitstream coding. Returns a pointer to the internal buffer. +uint8_t* VP8LBitWriterFinish(VP8LBitWriter* const bw); +// Release any pending memory and zeroes the object. +void VP8LBitWriterWipeOut(VP8LBitWriter* const bw); -void VP8LBitWriterDestroy(VP8LBitWriter* const bw); +// Internal function for VP8LPutBits flushing 32 bits from the written state. +void VP8LPutBitsFlushBits(VP8LBitWriter* const bw); -// This function writes bits into bytes in increasing addresses, and within -// a byte least-significant-bit first. -// -// The function can write up to 16 bits in one go with WriteBits -// Example: let's assume that 3 bits (Rs below) have been written already: -// -// BYTE-0 BYTE+1 BYTE+2 -// -// 0000 0RRR 0000 0000 0000 0000 -// -// Now, we could write 5 or less bits in MSB by just sifting by 3 -// and OR'ing to BYTE-0. -// -// For n bits, we take the last 5 bytes, OR that with high bits in BYTE-0, -// and locate the rest in BYTE+1 and BYTE+2. -// +// PutBits internal function used in the 16 bit vp8l_wtype_t case. +void VP8LPutBitsInternal(VP8LBitWriter* const bw, uint32_t bits, int n_bits); + +// This function writes bits into bytes in increasing addresses (little endian), +// and within a byte least-significant-bit first. +// This function can write up to 32 bits in one go, but VP8LBitReader can only +// read 24 bits max (VP8L_MAX_NUM_BIT_READ). // VP8LBitWriter's error_ flag is set in case of memory allocation error. -void VP8LWriteBits(VP8LBitWriter* const bw, int n_bits, uint32_t bits); +static WEBP_INLINE void VP8LPutBits(VP8LBitWriter* const bw, + uint32_t bits, int n_bits) { + if (sizeof(vp8l_wtype_t) == 4) { + if (n_bits > 0) { + if (bw->used_ >= 32) { + VP8LPutBitsFlushBits(bw); + } + bw->bits_ |= (vp8l_atype_t)bits << bw->used_; + bw->used_ += n_bits; + } + } else { + VP8LPutBitsInternal(bw, bits, n_bits); + } +} //------------------------------------------------------------------------------ -#if defined(__cplusplus) || defined(c_plusplus) +#ifdef __cplusplus } // extern "C" #endif |