1a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Copyright 2011 Google Inc. All Rights Reserved. 2a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// 30406ce1417f76f2034833414dcecc9f56253640cVikas Arora// Use of this source code is governed by a BSD-style license 40406ce1417f76f2034833414dcecc9f56253640cVikas Arora// that can be found in the COPYING file in the root of the source 50406ce1417f76f2034833414dcecc9f56253640cVikas Arora// tree. An additional intellectual property rights grant can be found 60406ce1417f76f2034833414dcecc9f56253640cVikas Arora// in the file PATENTS. All contributing project authors may 70406ce1417f76f2034833414dcecc9f56253640cVikas Arora// be found in the AUTHORS file in the root of the source tree. 8a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// ----------------------------------------------------------------------------- 9a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// 10a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Bit writing and boolean coder 11a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// 12a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Author: Skal (pascal.massimino@gmail.com) 13a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 14a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#ifndef WEBP_UTILS_BIT_WRITER_H_ 15a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#define WEBP_UTILS_BIT_WRITER_H_ 16a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 17a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#include "webp/types.h" 18a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 198b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora#ifdef __cplusplus 20a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroraextern "C" { 21a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#endif 22a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 23a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora//------------------------------------------------------------------------------ 24a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Bit-writing 25a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 26a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroratypedef struct VP8BitWriter VP8BitWriter; 27a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arorastruct VP8BitWriter { 28a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int32_t range_; // range-1 29a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int32_t value_; 30a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int run_; // number of outstanding bits 31a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int nb_bits_; // number of pending bits 32a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora uint8_t* buf_; // internal buffer. Re-allocated regularly. Not owned. 33a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora size_t pos_; 34a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora size_t max_pos_; 35a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int error_; // true in case of error 36a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora}; 37a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 38a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Initialize the object. Allocates some initial memory based on expected_size. 39a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroraint VP8BitWriterInit(VP8BitWriter* const bw, size_t expected_size); 40a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Finalize the bitstream coding. Returns a pointer to the internal buffer. 41a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arorauint8_t* VP8BitWriterFinish(VP8BitWriter* const bw); 42a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Release any pending memory and zeroes the object. Not a mandatory call. 43a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Only useful in case of error, when the internal buffer hasn't been grabbed! 44a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroravoid VP8BitWriterWipeOut(VP8BitWriter* const bw); 45a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 46a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroraint VP8PutBit(VP8BitWriter* const bw, int bit, int prob); 47a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroraint VP8PutBitUniform(VP8BitWriter* const bw, int bit); 48a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroravoid VP8PutValue(VP8BitWriter* const bw, int value, int nb_bits); 49a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroravoid VP8PutSignedValue(VP8BitWriter* const bw, int value, int nb_bits); 50a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 51a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Appends some bytes to the internal buffer. Data is copied. 52a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroraint VP8BitWriterAppend(VP8BitWriter* const bw, 53a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora const uint8_t* data, size_t size); 54a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 55a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// return approximate write position (in bits) 56a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arorastatic WEBP_INLINE uint64_t VP8BitWriterPos(const VP8BitWriter* const bw) { 57a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora return (uint64_t)(bw->pos_ + bw->run_) * 8 + 8 + bw->nb_bits_; 58a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} 59a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 60a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Returns a pointer to the internal buffer. 61a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arorastatic WEBP_INLINE uint8_t* VP8BitWriterBuf(const VP8BitWriter* const bw) { 62a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora return bw->buf_; 63a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} 64a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Returns the size of the internal buffer. 65a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arorastatic WEBP_INLINE size_t VP8BitWriterSize(const VP8BitWriter* const bw) { 66a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora return bw->pos_; 67a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} 68a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 69a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora//------------------------------------------------------------------------------ 70a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// VP8LBitWriter 71a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 72af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora#if defined(__x86_64__) || defined(_M_X64) // 64bit 73af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Aroratypedef uint64_t vp8l_atype_t; // accumulator type 74af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Aroratypedef uint32_t vp8l_wtype_t; // writing type 75af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora#define WSWAP HToLE32 76af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora#else 77af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Aroratypedef uint32_t vp8l_atype_t; 78af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Aroratypedef uint16_t vp8l_wtype_t; 79af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora#define WSWAP HToLE16 80af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora#endif 81a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 82af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Aroratypedef struct { 83af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora vp8l_atype_t bits_; // bit accumulator 84af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora int used_; // number of bits used in accumulator 85af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora uint8_t* buf_; // start of buffer 86af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora uint8_t* cur_; // current write position 87af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora uint8_t* end_; // end of buffer 88af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora 89af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora // After all bits are written (VP8LBitWriterFinish()), the caller must observe 90af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora // the state of error_. A value of 1 indicates that a memory allocation 91af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora // failure has happened during bit writing. A value of 0 indicates successful 92a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora // writing of bits. 93a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora int error_; 94a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} VP8LBitWriter; 95a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 96a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arorastatic WEBP_INLINE size_t VP8LBitWriterNumBytes(VP8LBitWriter* const bw) { 97af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora return (bw->cur_ - bw->buf_) + ((bw->used_ + 7) >> 3); 98a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} 99a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 100af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arorauint8_t* VP8LBitWriterFinish(VP8LBitWriter* const bw); 101a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 102a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// Returns 0 in case of memory allocation error. 103a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroraint VP8LBitWriterInit(VP8LBitWriter* const bw, size_t expected_size); 104a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 105a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroravoid VP8LBitWriterDestroy(VP8LBitWriter* const bw); 106a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 107af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora// This function writes bits into bytes in increasing addresses (little endian), 108af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora// and within a byte least-significant-bit first. 109af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora// This function can write up to 32 bits in one go, but VP8LBitReader can only 110af51b94a435132e9014c324e25fb686b3d07a8c8Vikas Arora// read 24 bits max (VP8L_MAX_NUM_BIT_READ). 111a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora// VP8LBitWriter's error_ flag is set in case of memory allocation error. 112a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Aroravoid VP8LWriteBits(VP8LBitWriter* const bw, int n_bits, uint32_t bits); 113a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 114a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora//------------------------------------------------------------------------------ 115a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 1168b720228d581a84fd173b6dcb2fa295b59db489aVikas Arora#ifdef __cplusplus 117a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora} // extern "C" 118a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#endif 119a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora 120a2415724fb3466168b2af5b08bd94ba732c0e753Vikas Arora#endif /* WEBP_UTILS_BIT_WRITER_H_ */ 121