1 /*
2 * Copyright (C) 2011 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "M4OSA_Types.h"
18 #include "M4OSA_Debug.h"
19
20 #include "M4VD_Tools.h"
21
22 /**
23 ************************************************************************
24 * @file M4VD_Tools.c
25 * @brief
26 * @note This file implements helper functions for Bitstream parser
27 ************************************************************************
28 */
29
M4VD_Tools_GetBitsFromMemory(M4VS_Bitstream_ctxt * parsingCtxt,M4OSA_UInt32 nb_bits)30 M4OSA_UInt32 M4VD_Tools_GetBitsFromMemory(M4VS_Bitstream_ctxt* parsingCtxt,
31 M4OSA_UInt32 nb_bits)
32 {
33 M4OSA_UInt32 code;
34 M4OSA_UInt32 i;
35 code = 0;
36 for (i = 0; i < nb_bits; i++)
37 {
38 if (parsingCtxt->stream_index == 8)
39 {
40 //M4OSA_memcpy( (M4OSA_MemAddr8)&(parsingCtxt->stream_byte), parsingCtxt->in,
41 // sizeof(unsigned char));
42 parsingCtxt->stream_byte = (unsigned char)(parsingCtxt->in)[0];
43 parsingCtxt->in++;
44 //fread(&stream_byte, sizeof(unsigned char),1,in);
45 parsingCtxt->stream_index = 0;
46 }
47 code = (code << 1);
48 code |= ((parsingCtxt->stream_byte & 0x80) >> 7);
49
50 parsingCtxt->stream_byte = (parsingCtxt->stream_byte << 1);
51 parsingCtxt->stream_index++;
52 }
53
54 return code;
55 }
56
M4VD_Tools_WriteBitsToMemory(M4OSA_UInt32 bitsToWrite,M4OSA_MemAddr32 dest_bits,M4OSA_UInt8 offset,M4OSA_UInt8 nb_bits)57 M4OSA_ERR M4VD_Tools_WriteBitsToMemory(M4OSA_UInt32 bitsToWrite,
58 M4OSA_MemAddr32 dest_bits,
59 M4OSA_UInt8 offset, M4OSA_UInt8 nb_bits)
60 {
61 M4OSA_UInt8 i,j;
62 M4OSA_UInt32 temp_dest = 0, mask = 0, temp = 1;
63 M4OSA_UInt32 input = bitsToWrite;
64 input = (input << (32 - nb_bits - offset));
65
66 /* Put destination buffer to 0 */
67 for(j=0;j<3;j++)
68 {
69 for(i=0;i<8;i++)
70 {
71 if((j*8)+i >= offset && (j*8)+i < nb_bits + offset)
72 {
73 mask |= (temp << ((7*(j+1))-i+j));
74 }
75 }
76 }
77 mask = ~mask;
78 *dest_bits &= mask;
79
80 /* Parse input bits, and fill output buffer */
81 for(j=0;j<3;j++)
82 {
83 for(i=0;i<8;i++)
84 {
85 if((j*8)+i >= offset && (j*8)+i < nb_bits + offset)
86 {
87 temp = ((input & (0x80000000 >> offset)) >> (31-offset));
88 //*dest_bits |= (temp << (31 - i));
89 *dest_bits |= (temp << ((7*(j+1))-i+j));
90 input = (input << 1);
91 }
92 }
93 }
94
95 return M4NO_ERROR;
96 }
97
98
99
100