1e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard/* 2e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** Copyright 2003-2010, VisualOn, Inc. 3e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** 4e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** Licensed under the Apache License, Version 2.0 (the "License"); 5e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** you may not use this file except in compliance with the License. 6e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** You may obtain a copy of the License at 7e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** 8e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** http://www.apache.org/licenses/LICENSE-2.0 9e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** 10e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** Unless required by applicable law or agreed to in writing, software 11e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** distributed under the License is distributed on an "AS IS" BASIS, 12e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** See the License for the specific language governing permissions and 14e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard ** limitations under the License. 15e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard */ 16e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard/******************************************************************************* 17e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard File: bitbuffer.c 18e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 19e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard Content: Bit Buffer Management functions 20e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard 21956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong*******************************************************************************/ 22956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 23956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong#include "bitbuffer.h" 24956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 25956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong/***************************************************************************** 26956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 27956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* function name: CreateBitBuffer 28956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* description: create and init Bit Buffer Management 29956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 30956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong*****************************************************************************/ 31956c553ab0ce72f8074ad0fda2ffd66a0305700cJames DongHANDLE_BIT_BUF CreateBitBuffer(HANDLE_BIT_BUF hBitBuf, 32956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong UWord8 *pBitBufBase, 33956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong Word16 bitBufSize) 34956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong{ 35956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong assert(bitBufSize*8 <= 32768); 36956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 37b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->pBitBufBase = pBitBufBase; 38b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->pBitBufEnd = pBitBufBase + bitBufSize - 1; 39956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 40b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->pWriteNext = pBitBufBase; 41956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 42956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong hBitBuf->cache = 0; 43b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard 44b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->wBitPos = 0; 45b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->cntBits = 0; 46b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard 47b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->size = (bitBufSize << 3); 48b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->isValid = 1; 49956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 50956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong return hBitBuf; 51956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong} 52956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 53956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong/***************************************************************************** 54956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 55956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* function name: DeleteBitBuffer 56956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* description: uninit Bit Buffer Management 57956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 58956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong*****************************************************************************/ 59956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dongvoid DeleteBitBuffer(HANDLE_BIT_BUF *hBitBuf) 60956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong{ 61e2e838afcf03e603a41a0455846eaf9614537c16Mans Rullgard if(*hBitBuf) 62b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard (*hBitBuf)->isValid = 0; 63b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard *hBitBuf = NULL; 64956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong} 65956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 66956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong/***************************************************************************** 67956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 68956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* function name: ResetBitBuf 69956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* description: reset Bit Buffer Management 70956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 71956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong*****************************************************************************/ 72956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dongvoid ResetBitBuf(HANDLE_BIT_BUF hBitBuf, 73956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong UWord8 *pBitBufBase, 74956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong Word16 bitBufSize) 75956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong{ 76b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->pBitBufBase = pBitBufBase; 77b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->pBitBufEnd = pBitBufBase + bitBufSize - 1; 78b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard 79956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 80b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->pWriteNext = pBitBufBase; 81b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard 82b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->wBitPos = 0; 83b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->cntBits = 0; 84956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 85956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong hBitBuf->cache = 0; 86956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong} 87956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 88956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong/***************************************************************************** 89956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 90956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* function name: CopyBitBuf 91956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* description: copy Bit Buffer Management 92956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 93956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong*****************************************************************************/ 94956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dongvoid CopyBitBuf(HANDLE_BIT_BUF hBitBufSrc, 95956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong HANDLE_BIT_BUF hBitBufDst) 96956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong{ 97b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard *hBitBufDst = *hBitBufSrc; 98956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong} 99956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 100956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong/***************************************************************************** 101956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 102956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* function name: GetBitsAvail 103956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* description: get available bits 104956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 105956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong*****************************************************************************/ 106956c553ab0ce72f8074ad0fda2ffd66a0305700cJames DongWord16 GetBitsAvail(HANDLE_BIT_BUF hBitBuf) 107956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong{ 108956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong return hBitBuf->cntBits; 109956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong} 110956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 111956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong/***************************************************************************** 112956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 113956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* function name: WriteBits 114956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* description: write bits to the buffer 115956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong* 116956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong*****************************************************************************/ 117956c553ab0ce72f8074ad0fda2ffd66a0305700cJames DongWord16 WriteBits(HANDLE_BIT_BUF hBitBuf, 1185e9afe434d8207fb0af6e191cca671ab74cfe878Martin Storsjo UWord32 writeValue, 119956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong Word16 noBitsToWrite) 120956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong{ 121956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong Word16 wBitPos; 122956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 123956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong assert(noBitsToWrite <= (Word16)sizeof(Word32)*8); 124956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 125956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong if(noBitsToWrite == 0) 126956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong return noBitsToWrite; 127956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 128b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard hBitBuf->cntBits += noBitsToWrite; 129956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong 130956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong wBitPos = hBitBuf->wBitPos; 131956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong wBitPos += noBitsToWrite; 1323989d5c21ce6d1f3492c9e5484d610d5d66abd9eMartin Storsjo writeValue &= ~(0xffffffff << noBitsToWrite); // Mask out everything except the lowest noBitsToWrite bits 133b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard writeValue <<= 32 - wBitPos; 134956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong writeValue |= hBitBuf->cache; 135b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard 136b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard while (wBitPos >= 8) 137956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong { 138956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong UWord8 tmp; 139956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong tmp = (UWord8)((writeValue >> 24) & 0xFF); 140b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard 141b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard *hBitBuf->pWriteNext++ = tmp; 142956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong writeValue <<= 8; 143956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong wBitPos -= 8; 144956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong } 145b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard 146956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong hBitBuf->wBitPos = wBitPos; 147956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong hBitBuf->cache = writeValue; 148b676a05348e4c516fa8b57e33b10548e6142c3f8Mans Rullgard 149956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong return noBitsToWrite; 150956c553ab0ce72f8074ad0fda2ffd66a0305700cJames Dong} 151