SDL  2.0
SDL_test_crc32.c
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1 /*
2  Simple DirectMedia Layer
3  Copyright (C) 1997-2016 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 
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 
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 
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 
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 
159 {
160  if (crcContext==NULL) {
161  return -1;
162  }
163 
164  return 0;
165 }
#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)
int SDLTest_Crc32Calc(SDLTest_Crc32Context *crcContext, CrcUint8 *inBuf, CrcUint32 inLen, CrcUint32 *crc32)
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 in i)
Definition: SDL_x11sym.h:42
#define NULL
Definition: begin_code.h:143
#define CrcUint32
int SDLTest_Crc32Done(SDLTest_Crc32Context *crcContext)
clean up CRC context
int SDLTest_Crc32CalcStart(SDLTest_Crc32Context *crcContext, CrcUint32 *crc32)
#define CrcUint8
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:42