SDL  2.0
SDL_test_crc32.c
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2017 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 
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 /* un-used
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 
91 /* Start crc calculation */
92 
94 {
95  /* Sanity check pointers */
96  if (crcContext==NULL) {
97  *crc32=0;
98  return -1;
99  }
100 
101  /*
102  * Preload shift register, per CRC-32 spec
103  */
104  *crc32 = 0xffffffff;
105 
106  return 0;
107 }
108 
109 /* Finish crc calculation */
110 
112 {
113  /* Sanity check pointers */
114  if (crcContext==NULL) {
115  *crc32=0;
116  return -1;
117  }
118 
119  /*
120  * Return complement, per CRC-32 spec
121  */
122  *crc32 = (~(*crc32));
123 
124  return 0;
125 }
126 
127 /* Include memory block in crc */
128 
130 {
131  CrcUint8 *p;
132  register CrcUint32 crc;
133 
134  if (crcContext==NULL) {
135  *crc32=0;
136  return -1;
137  }
138 
139  if (inBuf==NULL) {
140  return -1;
141  }
142 
143  /*
144  * Calculate CRC from data
145  */
146  crc = *crc32;
147  for (p = inBuf; inLen > 0; ++p, --inLen) {
148 #ifdef ORIGINAL_METHOD
149  crc = (crc << 8) ^ crcContext->crc32_table[(crc >> 24) ^ *p];
150 #else
151  crc = ((crc >> 8) & 0x00FFFFFF) ^ crcContext->crc32_table[ (crc ^ *p) & 0xFF ];
152 #endif
153  }
154  *crc32 = crc;
155 
156  return 0;
157 }
158 
160 {
161  if (crcContext==NULL) {
162  return -1;
163  }
164 
165  return 0;
166 }
167 
168 /* vi: set ts=4 sw=4 expandtab: */
#define CRC32_POLY
int SDLTest_Crc32Init(SDLTest_Crc32Context *crcContext)
Initialize the CRC context.
GLfloat GLfloat p
CrcUint32 crc32_table[256]
int SDLTest_Crc32CalcEnd(SDLTest_Crc32Context *crcContext, CrcUint32 *crc32)
int SDLTest_Crc32CalcBuffer(SDLTest_Crc32Context *crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display Drawable _Xconst char unsigned int unsigned int return Display Pixmap Pixmap XColor XColor unsigned int unsigned int return Display _Xconst char char int char return Display Visual unsigned int int int char unsigned int unsigned int in i)
Definition: SDL_x11sym.h:50
const GLubyte * c
return Display return Display Bool Bool int int int return Display XEvent Bool(*) XPointer return Display return Display Drawable _Xconst char unsigned int unsigned int return Display Pixmap Pixmap XColor XColor unsigned int unsigned int return Display _Xconst char char int char return Display Visual unsigned int int int char unsigned int unsigned int int in j)
Definition: SDL_x11sym.h:50
#define NULL
Definition: begin_code.h:164
#define CrcUint32
int SDLTest_Crc32Done(SDLTest_Crc32Context *crcContext)
clean up CRC context
int SDLTest_Crc32CalcStart(SDLTest_Crc32Context *crcContext, CrcUint32 *crc32)
#define CrcUint8