1 /*!
2 * \copy
3 * Copyright (c) 2009-2013, Cisco Systems
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * * Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 *
13 * * Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in
15 * the documentation and/or other materials provided with the
16 * distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
21 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
22 * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
24 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
25 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
26 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
28 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 *
31 *
32 * \file bit_stream.cpp
33 *
34 * \brief Reading / writing bit-stream
35 *
36 * \date 03/10/2009 Created
37 *
38 *************************************************************************************
39 */
40 #include "bit_stream.h"
41 #include "error_code.h"
42
43 namespace WelsDec {
44
GetValue4Bytes(uint8_t * pDstNal)45 inline uint32_t GetValue4Bytes (uint8_t* pDstNal) {
46 uint32_t uiValue = 0;
47 uiValue = (pDstNal[0] << 24) | (pDstNal[1] << 16) | (pDstNal[2] << 8) | (pDstNal[3]);
48 return uiValue;
49 }
50
InitReadBits(PBitStringAux pBitString,intX_t iEndOffset)51 int32_t InitReadBits (PBitStringAux pBitString, intX_t iEndOffset) {
52 if (pBitString->pCurBuf >= (pBitString->pEndBuf - iEndOffset)) {
53 return ERR_INFO_INVALID_ACCESS;
54 }
55 pBitString->uiCurBits = GetValue4Bytes (pBitString->pCurBuf);
56 pBitString->pCurBuf += 4;
57 pBitString->iLeftBits = -16;
58 return ERR_NONE;
59 }
60
61 /*!
62 * \brief input bits for decoder or initialize bitstream writing in encoder
63 *
64 * \param pBitString Bit string auxiliary pointer
65 * \param kpBuf bit-stream buffer
66 * \param kiSize size in bits for decoder; size in bytes for encoder
67 *
68 * \return 0: success, other: fail
69 */
DecInitBits(PBitStringAux pBitString,const uint8_t * kpBuf,const int32_t kiSize)70 int32_t DecInitBits (PBitStringAux pBitString, const uint8_t* kpBuf, const int32_t kiSize) {
71 const int32_t kiSizeBuf = (kiSize + 7) >> 3;
72 uint8_t* pTmp = (uint8_t*)kpBuf;
73
74 if (NULL == pTmp)
75 return ERR_INFO_INVALID_ACCESS;
76
77 pBitString->pStartBuf = pTmp; // buffer to start position
78 pBitString->pEndBuf = pTmp + kiSizeBuf; // buffer + length
79 pBitString->iBits = kiSize; // count bits of overall bitstreaming inputindex;
80 pBitString->pCurBuf = pBitString->pStartBuf;
81 int32_t iErr = InitReadBits (pBitString, 0);
82 if (iErr) {
83 return iErr;
84 }
85 return ERR_NONE;
86 }
87
RBSP2EBSP(uint8_t * pDstBuf,uint8_t * pSrcBuf,const int32_t kiSize)88 void RBSP2EBSP (uint8_t* pDstBuf, uint8_t* pSrcBuf, const int32_t kiSize) {
89 uint8_t* pSrcPointer = pSrcBuf;
90 uint8_t* pDstPointer = pDstBuf;
91 uint8_t* pSrcEnd = pSrcBuf + kiSize;
92 int32_t iZeroCount = 0;
93
94 while (pSrcPointer < pSrcEnd) {
95 if (iZeroCount == 2 && *pSrcPointer <= 3) {
96 //add the code 0x03
97 *pDstPointer++ = 3;
98 iZeroCount = 0;
99 }
100 if (*pSrcPointer == 0) {
101 ++ iZeroCount;
102 } else {
103 iZeroCount = 0;
104 }
105 *pDstPointer++ = *pSrcPointer++;
106 }
107 }
108
109 } // namespace WelsDec
110
111