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SDL_test_crc32.c
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1 /*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
4
5 This software is provided 'as-is', without any express or implied
6 warranty. In no event will the authors be held liable for any damages
7 arising from the use of this software.
8
9 Permission is granted to anyone to use this software for any purpose,
10 including commercial applications, and to alter it and redistribute it
11 freely, subject to the following restrictions:
12
13 1. The origin of this software must not be misrepresented; you must not
14 claim that you wrote the original software. If you use this software
15 in a product, an acknowledgment in the product documentation would be
16 appreciated but is not required.
17 2. Altered source versions must be plainly marked as such, and must not be
18 misrepresented as being the original software.
19 3. This notice may not be removed or altered from any source distribution.
20 */
21
22 /*
23
24 Used by the test execution component.
25 Original source code contributed by A. Schiffler for GSOC project.
26
27 */
28
29 #include "SDL_config.h"
30
31 #include "SDL_test.h"
32
33
34 int SDLTest_Crc32Init(SDLTest_Crc32Context *crcContext)
35 {
36 int i,j;
37 CrcUint32 c;
38
39 /* Sanity check context pointer */
40 if (crcContext==NULL) {
41 return -1;
42 }
43
44 /*
45 * Build auxiliary table for parallel byte-at-a-time CRC-32
46 */
47 #ifdef ORIGINAL_METHOD
48 for (i = 0; i < 256; ++i) {
49 for (c = i << 24, j = 8; j > 0; --j) {
50 c = c & 0x80000000 ? (c << 1) ^ CRC32_POLY : (c << 1);
51 }
52 crcContext->crc32_table[i] = c;
53 }
54 #else
55 for (i=0; i<256; i++) {
56 c = i;
57 for (j=8; j>0; j--) {
58 if (c & 1) {
59 c = (c >> 1) ^ CRC32_POLY;
60 } else {
61 c >>= 1;
62 }
63 }
64 crcContext->crc32_table[i] = c;
65 }
66 #endif
67
68 return 0;
69 }
70
71 /* Complete CRC32 calculation on a memory block */
72
73 int SDLTest_Crc32Calc(SDLTest_Crc32Context * crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
74 {
75 if (SDLTest_Crc32CalcStart(crcContext,crc32)) {
76 return -1;
77 }
78
79 if (SDLTest_Crc32CalcBuffer(crcContext, inBuf, inLen, crc32)) {
80 return -1;
81 }
82
83 if (SDLTest_Crc32CalcEnd(crcContext, crc32)) {
84 return -1;
85 }
86
87 return 0;
88 }
89
90 /* Start crc calculation */
91
92 int SDLTest_Crc32CalcStart(SDLTest_Crc32Context * crcContext, CrcUint32 *crc32)
93 {
94 /* Sanity check pointers */
95 if (crcContext==NULL) {
96 *crc32=0;
97 return -1;
98 }
99
100 /*
101 * Preload shift register, per CRC-32 spec
102 */
103 *crc32 = 0xffffffff;
104
105 return 0;
106 }
107
108 /* Finish crc calculation */
109
110 int SDLTest_Crc32CalcEnd(SDLTest_Crc32Context * crcContext, CrcUint32 *crc32)
111 {
112 /* Sanity check pointers */
113 if (crcContext==NULL) {
114 *crc32=0;
115 return -1;
116 }
117
118 /*
119 * Return complement, per CRC-32 spec
120 */
121 *crc32 = (~(*crc32));
122
123 return 0;
124 }
125
126 /* Include memory block in crc */
127
128 int SDLTest_Crc32CalcBuffer(SDLTest_Crc32Context * crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
129 {
130 CrcUint8 *p;
131 register CrcUint32 crc;
132
133 if (crcContext==NULL) {
134 *crc32=0;
135 return -1;
136 }
137
138 if (inBuf==NULL) {
139 return -1;
140 }
141
142 /*
143 * Calculate CRC from data
144 */
145 crc = *crc32;
146 for (p = inBuf; inLen > 0; ++p, --inLen) {
147 #ifdef ORIGINAL_METHOD
148 crc = (crc << 8) ^ crcContext->crc32_table[(crc >> 24) ^ *p];
149 #else
150 crc = ((crc >> 8) & 0x00FFFFFF) ^ crcContext->crc32_table[ (crc ^ *p) & 0xFF ];
151 #endif
152 }
153 *crc32 = crc;
154
155 return 0;
156 }
157
158 int SDLTest_Crc32Done(SDLTest_Crc32Context * crcContext)
159 {
160 if (crcContext==NULL) {
161 return -1;
162 }
163
164 return 0;
165 }
CRC32_POLY
#define CRC32_POLY
Definition: SDL_test_crc32.h:60
SDL_test.h
SDLTest_Crc32Done
int SDLTest_Crc32Done(SDLTest_Crc32Context *crcContext)
Definition: SDL_test_crc32.c:158
NULL
#define NULL
Definition: ftobjs.h:61
j
int32_t j
Definition: e_log.c:102
SDLTest_Crc32Context::crc32_table
CrcUint32 crc32_table[256]
Definition: SDL_test_crc32.h:67
SDL_config.h
SDLTest_Crc32Calc
int SDLTest_Crc32Calc(SDLTest_Crc32Context *crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
Definition: SDL_test_crc32.c:73
p
GLfloat GLfloat p
Definition: glew.h:14938
c
const GLfloat * c
Definition: glew.h:14913
crc32
unsigned long ZEXPORT crc32(unsigned long crc, const unsigned char FAR *buf, uInt len)
Definition: crc32.c:221
SDLTest_Crc32CalcStart
int SDLTest_Crc32CalcStart(SDLTest_Crc32Context *crcContext, CrcUint32 *crc32)
Definition: SDL_test_crc32.c:92
SDLTest_Crc32CalcEnd
int SDLTest_Crc32CalcEnd(SDLTest_Crc32Context *crcContext, CrcUint32 *crc32)
Definition: SDL_test_crc32.c:110
SDLTest_Crc32Init
int SDLTest_Crc32Init(SDLTest_Crc32Context *crcContext)
Definition: SDL_test_crc32.c:34
SDLTest_Crc32CalcBuffer
int SDLTest_Crc32CalcBuffer(SDLTest_Crc32Context *crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
Definition: SDL_test_crc32.c:128
SDLTest_Crc32Context
Definition: SDL_test_crc32.h:66
CrcUint32
#define CrcUint32
Definition: SDL_test_crc32.h:51
i
int i
Definition: pngrutil.c:1377
CrcUint8
#define CrcUint8
Definition: SDL_test_crc32.h:54