1/* ------------------------------------------------------------------
2 * Copyright (C) 1998-2009 PacketVideo
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
13 * express or implied.
14 * See the License for the specific language governing permissions
15 * and limitations under the License.
16 * -------------------------------------------------------------------
17 */
18/*
19 * File:    crccheck.cpp
20 * Author:  Russell Hayashida (rhayashida@packetvideo.com)
21 * Date:    February 13, 2002
22 * Comment: CRC procedures
23 */
24
25#include "crccheck_cpp.h"
26#include <limits.h>
27
28#define CRC_X8 0xe0     /* X8+X2+X+1( 0x107 <-> 0xe0 ) */
29#define CRC_X 0x8408U   /* X16+X12+X5+1 ( 0x11021 <-> 0x8408 )  */
30
31
32//Initialize both tables.
33OSCL_EXPORT_REF CRC::CRC()
34{
35    int i;
36    uint8 j, Crc;
37
38    for (i = 0 ; i <= (int) UCHAR_MAX ; i ++)
39    {
40        Crc = (uint8) i;
41        for (j =  0 ; j < CHAR_BIT ; j ++)
42        {
43            if (Crc & 1)
44                Crc = (uint8)((Crc >> 1) ^ CRC_X8);        /* Generator Polynomial          */
45            else
46                Crc >>= 1;
47        }
48        CrcTbl8[i] = Crc;
49    }
50
51
52    uint16  n, m, Crc16;
53
54    for (n = 0 ; n <= UCHAR_MAX ; n++)
55    {
56        Crc16 = n;
57        for (m =  0 ; m < CHAR_BIT ; m++)
58        {
59            if (Crc16 & 1)
60                Crc16 = (uint16)((Crc16 >> 1) ^ CRC_X);            /* Genarator Polynomial          */
61            else
62                Crc16 >>= 1;
63        }
64        CrcTbl16[ n ] = Crc16;          /* CRC Infomaiton Set           */
65    }
66}
67
68
69OSCL_EXPORT_REF uint8 CRC::Crc8Check(uint8 *pAlPdu, int16 Size)
70{
71    uint8   crc;
72
73    crc = 0;
74    while (--Size >= 0)
75    {
76        crc = (uint8)((crc >> CHAR_BIT) ^ CrcTbl8[ crc ^ *pAlPdu++ ]);
77    }
78    return (uint8)(crc & 0xffU);
79}
80
81OSCL_EXPORT_REF uint8 CRC::Crc8Check(Packet *pPkt)
82{
83    uint8   crc;
84    uint8   *pData = NULL;
85    int32   fragIdx, curSize, dataSize;
86    BufferFragment* frag = NULL;
87
88    crc = 0;
89    fragIdx = 0;
90    dataSize = pPkt->GetMediaSize();
91    curSize = 0;
92    while (--dataSize >= 0)
93    {
94
95        if ((--curSize) <= 0)
96        {
97            frag = pPkt->GetMediaFragment(fragIdx);
98            fragIdx++;
99            curSize = frag->len;
100            pData = (uint8 *) frag->ptr;
101        }
102        crc = (uint8)((crc >> CHAR_BIT) ^ CrcTbl8[ crc ^ *pData++ ]);
103    }
104    return (uint8)(crc & 0xffU);
105}
106
107OSCL_EXPORT_REF uint8 CRC::Crc8Check(OsclSharedPtr<PVMFMediaDataImpl>& mediaData, bool hasCRC)
108{
109    uint8   crc;
110    uint8   *pData = NULL;
111    int32   fragIdx, curSize, dataSize;
112    OsclRefCounterMemFrag frag;
113
114    crc = 0;
115    fragIdx = 0;
116    //Don't include CRC field in calculation
117    if (hasCRC)
118    {
119        dataSize = mediaData->getFilledSize() - 1;
120    }
121    else
122    {
123        dataSize = mediaData->getFilledSize();
124    }
125    curSize = 0;
126    while (--dataSize >= 0)
127    {
128
129        if ((--curSize) <= 0)
130        {
131            mediaData->getMediaFragment(fragIdx, frag);
132            fragIdx++;
133            curSize = frag.getMemFragSize();
134            pData = (uint8 *) frag.getMemFragPtr();
135        }
136        crc = (uint8)((crc >> CHAR_BIT) ^ CrcTbl8[ crc ^ *pData++ ]);
137    }
138    return (uint8)(crc & 0xffU);
139}
140
141
142OSCL_EXPORT_REF uint16 CRC::Crc16Check(uint8 *pAlPdu, int16 Size)
143{
144    uint16  crc;
145
146    crc = 0xffffU;
147    while (--Size >= 0)
148    {
149        crc = (uint16)((crc >> CHAR_BIT) ^ CrcTbl16[(uint8)crc ^ *pAlPdu++ ]);
150    }
151    return (uint16)(crc ^ 0xffffU);
152    /*
153    crc ^= 0xffffU;
154    crc = (crc&0xff)<<8 | crc>>8;
155    return crc;
156    */
157}
158
159OSCL_EXPORT_REF uint16 CRC::Crc16Check(Packet *pPkt)
160{
161    uint16  crc;
162    uint8   *pData = NULL;
163    int32   fragIdx, curSize, dataSize;
164    BufferFragment* frag = NULL;
165
166    crc = 0xffffU;
167    fragIdx = 0;
168    dataSize = pPkt->GetMediaSize();
169    curSize = 0;
170    while (--dataSize >= 0)
171    {
172
173        if ((--curSize) <= 0)
174        {
175            frag = pPkt->GetMediaFragment(fragIdx);
176            fragIdx++;
177            curSize = frag->len;
178            pData = (uint8 *) frag->ptr;
179        }
180        crc = (uint16)((crc >> CHAR_BIT) ^ CrcTbl16[(uint8)crc ^ *pData++ ]);
181    }
182    return (uint16)(crc ^ 0xffffU);
183    /*
184    crc ^= 0xffffU;
185    crc = (crc&0xff)<<8 | crc>>8;
186    return crc;
187    */
188
189}
190
191OSCL_EXPORT_REF uint16 CRC::Crc16Check(OsclSharedPtr<PVMFMediaDataImpl>& mediaData, bool hasCRC)
192{
193    uint16  crc;
194    uint8   *pData = NULL;
195    int32   fragIdx, curSize, dataSize;
196    OsclRefCounterMemFrag frag;
197
198    crc = 0xffffU;
199    fragIdx = 0;
200    //Don't include CRC field in calculation
201    if (hasCRC)
202    {
203        dataSize = mediaData->getFilledSize() - 2;
204    }
205    else
206    {
207        dataSize = mediaData->getFilledSize();
208    }
209    curSize = 0;
210
211    while (--dataSize >= 0)
212    {
213
214        if ((--curSize) <= 0)
215        {
216            mediaData->getMediaFragment(fragIdx, frag);
217            fragIdx++;
218            curSize = frag.getMemFragSize();
219            pData = (uint8 *) frag.getMemFragPtr();
220        }
221        crc = (uint16)((crc >> CHAR_BIT) ^ CrcTbl16[(uint8)crc ^ *pData++ ]);
222    }
223    return (uint16)(crc ^ 0xffffU);
224}
225