This repository has been archived by the owner on Feb 11, 2021. It is now read-only.
/
SDL_test_crc32.c
165 lines (131 loc) · 3.41 KB
1
2
/*
Simple DirectMedia Layer
3
Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
/*
24
Used by the test execution component.
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
Original source code contributed by A. Schiffler for GSOC project.
*/
#include "SDL_config.h"
#include "SDL_test.h"
int SDLTest_Crc32Init(SDLTest_Crc32Context *crcContext)
{
int i,j;
CrcUint32 c;
/* Sanity check context pointer */
if (crcContext==NULL) {
return -1;
42
43
}
44
/*
45
* Build auxiliary table for parallel byte-at-a-time CRC-32
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
*/
#ifdef ORIGINAL_METHOD
for (i = 0; i < 256; ++i) {
for (c = i << 24, j = 8; j > 0; --j) {
c = c & 0x80000000 ? (c << 1) ^ CRC32_POLY : (c << 1);
}
crcContext->crc32_table[i] = c;
}
#else
for (i=0; i<256; i++) {
c = i;
for (j=8; j>0; j--) {
if (c & 1) {
c = (c >> 1) ^ CRC32_POLY;
} else {
c >>= 1;
}
}
crcContext->crc32_table[i] = c;
}
#endif
67
68
69
70
71
72
73
74
75
76
77
return 0;
}
/* Complete CRC32 calculation on a memory block */
int SDLTest_Crc32Calc(SDLTest_Crc32Context * crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
{
if (SDLTest_Crc32CalcStart(crcContext,crc32)) {
return -1;
}
78
79
80
81
if (SDLTest_Crc32CalcBuffer(crcContext, inBuf, inLen, crc32)) {
return -1;
}
82
83
84
85
if (SDLTest_Crc32CalcEnd(crcContext, crc32)) {
return -1;
}
86
87
88
89
90
91
92
93
94
95
96
97
return 0;
}
/* Start crc calculation */
int SDLTest_Crc32CalcStart(SDLTest_Crc32Context * crcContext, CrcUint32 *crc32)
{
/* Sanity check pointers */
if (crcContext==NULL) {
*crc32=0;
return -1;
98
}
99
100
/*
101
* Preload shift register, per CRC-32 spec
102
103
104
105
106
107
108
109
110
111
112
113
114
115
*/
*crc32 = 0xffffffff;
return 0;
}
/* Finish crc calculation */
int SDLTest_Crc32CalcEnd(SDLTest_Crc32Context * crcContext, CrcUint32 *crc32)
{
/* Sanity check pointers */
if (crcContext==NULL) {
*crc32=0;
return -1;
116
117
}
118
/*
119
* Return complement, per CRC-32 spec
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
*/
*crc32 = (~(*crc32));
return 0;
}
/* Include memory block in crc */
int SDLTest_Crc32CalcBuffer(SDLTest_Crc32Context * crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
{
CrcUint8 *p;
register CrcUint32 crc;
if (crcContext==NULL) {
*crc32=0;
return -1;
}
137
138
139
140
141
142
if (inBuf==NULL) {
return -1;
}
/*
143
* Calculate CRC from data
144
145
146
*/
crc = *crc32;
for (p = inBuf; inLen > 0; ++p, --inLen) {
147
#ifdef ORIGINAL_METHOD
148
149
150
crc = (crc << 8) ^ crcContext->crc32_table[(crc >> 24) ^ *p];
#else
crc = ((crc >> 8) & 0x00FFFFFF) ^ crcContext->crc32_table[ (crc ^ *p) & 0xFF ];
151
152
#endif
}
153
*crc32 = crc;
154
155
156
157
158
159
160
161
return 0;
}
int SDLTest_Crc32Done(SDLTest_Crc32Context * crcContext)
{
if (crcContext==NULL) {
return -1;
162
}
163
164
165
return 0;
}