/[dtapublic]/projs/trunk/shared_source/c_datd/crchashfuncs.c
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1 //$Header$
2 //-------------------------------------------------------------------------------------------------
3 //This file is part of "David T. Ashley's Shared Source Code", a set of shared components
4 //integrated into many of David T. Ashley's projects.
5 //-------------------------------------------------------------------------------------------------
6 //This source code and any program in which it is compiled/used is provided under the MIT License,
7 //reproduced below.
8 //-------------------------------------------------------------------------------------------------
9 //Permission is hereby granted, free of charge, to any person obtaining a copy of
10 //this software and associated documentation files(the "Software"), to deal in the
11 //Software without restriction, including without limitation the rights to use,
12 //copy, modify, merge, publish, distribute, sublicense, and / or sell copies of the
13 //Software, and to permit persons to whom the Software is furnished to do so,
14 //subject to the following conditions :
15 //
16 //The above copyright notice and this permission notice shall be included in all
17 //copies or substantial portions of the Software.
18 //
19 //THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20 //IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21 //FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
22 //AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23 //LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24 //OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
25 //SOFTWARE.
26 //-------------------------------------------------------------------------------------------------
27 #define MODULE_CRCHASHFUNCS
28
29 #include <assert.h>
30 #include <stdio.h>
31 #include <string.h>
32
33 #include "crchashfuncs.h"
34
35
36 //This is the data table used to generate CRC-32 values. The code to
37 //generate these values isn't reproduced here (it was discarded after
38 //the values were generated), but this code originally came from a
39 //web page by Richard A. Ellingson. I do not at this time understand
40 //the math behind the generation or usage of this table.
41 static const unsigned CRCHASHFUNCS_crc32tab[256] =
42 {
43 /* [000] */ 0x00000000,
44 /* [001] */ 0x77073096,
45 /* [002] */ 0xEE0E612C,
46 /* [003] */ 0x990951BA,
47 /* [004] */ 0x076DC419,
48 /* [005] */ 0x706AF48F,
49 /* [006] */ 0xE963A535,
50 /* [007] */ 0x9E6495A3,
51 /* [008] */ 0x0EDB8832,
52 /* [009] */ 0x79DCB8A4,
53 /* [010] */ 0xE0D5E91E,
54 /* [011] */ 0x97D2D988,
55 /* [012] */ 0x09B64C2B,
56 /* [013] */ 0x7EB17CBD,
57 /* [014] */ 0xE7B82D07,
58 /* [015] */ 0x90BF1D91,
59 /* [016] */ 0x1DB71064,
60 /* [017] */ 0x6AB020F2,
61 /* [018] */ 0xF3B97148,
62 /* [019] */ 0x84BE41DE,
63 /* [020] */ 0x1ADAD47D,
64 /* [021] */ 0x6DDDE4EB,
65 /* [022] */ 0xF4D4B551,
66 /* [023] */ 0x83D385C7,
67 /* [024] */ 0x136C9856,
68 /* [025] */ 0x646BA8C0,
69 /* [026] */ 0xFD62F97A,
70 /* [027] */ 0x8A65C9EC,
71 /* [028] */ 0x14015C4F,
72 /* [029] */ 0x63066CD9,
73 /* [030] */ 0xFA0F3D63,
74 /* [031] */ 0x8D080DF5,
75 /* [032] */ 0x3B6E20C8,
76 /* [033] */ 0x4C69105E,
77 /* [034] */ 0xD56041E4,
78 /* [035] */ 0xA2677172,
79 /* [036] */ 0x3C03E4D1,
80 /* [037] */ 0x4B04D447,
81 /* [038] */ 0xD20D85FD,
82 /* [039] */ 0xA50AB56B,
83 /* [040] */ 0x35B5A8FA,
84 /* [041] */ 0x42B2986C,
85 /* [042] */ 0xDBBBC9D6,
86 /* [043] */ 0xACBCF940,
87 /* [044] */ 0x32D86CE3,
88 /* [045] */ 0x45DF5C75,
89 /* [046] */ 0xDCD60DCF,
90 /* [047] */ 0xABD13D59,
91 /* [048] */ 0x26D930AC,
92 /* [049] */ 0x51DE003A,
93 /* [050] */ 0xC8D75180,
94 /* [051] */ 0xBFD06116,
95 /* [052] */ 0x21B4F4B5,
96 /* [053] */ 0x56B3C423,
97 /* [054] */ 0xCFBA9599,
98 /* [055] */ 0xB8BDA50F,
99 /* [056] */ 0x2802B89E,
100 /* [057] */ 0x5F058808,
101 /* [058] */ 0xC60CD9B2,
102 /* [059] */ 0xB10BE924,
103 /* [060] */ 0x2F6F7C87,
104 /* [061] */ 0x58684C11,
105 /* [062] */ 0xC1611DAB,
106 /* [063] */ 0xB6662D3D,
107 /* [064] */ 0x76DC4190,
108 /* [065] */ 0x01DB7106,
109 /* [066] */ 0x98D220BC,
110 /* [067] */ 0xEFD5102A,
111 /* [068] */ 0x71B18589,
112 /* [069] */ 0x06B6B51F,
113 /* [070] */ 0x9FBFE4A5,
114 /* [071] */ 0xE8B8D433,
115 /* [072] */ 0x7807C9A2,
116 /* [073] */ 0x0F00F934,
117 /* [074] */ 0x9609A88E,
118 /* [075] */ 0xE10E9818,
119 /* [076] */ 0x7F6A0DBB,
120 /* [077] */ 0x086D3D2D,
121 /* [078] */ 0x91646C97,
122 /* [079] */ 0xE6635C01,
123 /* [080] */ 0x6B6B51F4,
124 /* [081] */ 0x1C6C6162,
125 /* [082] */ 0x856530D8,
126 /* [083] */ 0xF262004E,
127 /* [084] */ 0x6C0695ED,
128 /* [085] */ 0x1B01A57B,
129 /* [086] */ 0x8208F4C1,
130 /* [087] */ 0xF50FC457,
131 /* [088] */ 0x65B0D9C6,
132 /* [089] */ 0x12B7E950,
133 /* [090] */ 0x8BBEB8EA,
134 /* [091] */ 0xFCB9887C,
135 /* [092] */ 0x62DD1DDF,
136 /* [093] */ 0x15DA2D49,
137 /* [094] */ 0x8CD37CF3,
138 /* [095] */ 0xFBD44C65,
139 /* [096] */ 0x4DB26158,
140 /* [097] */ 0x3AB551CE,
141 /* [098] */ 0xA3BC0074,
142 /* [099] */ 0xD4BB30E2,
143 /* [100] */ 0x4ADFA541,
144 /* [101] */ 0x3DD895D7,
145 /* [102] */ 0xA4D1C46D,
146 /* [103] */ 0xD3D6F4FB,
147 /* [104] */ 0x4369E96A,
148 /* [105] */ 0x346ED9FC,
149 /* [106] */ 0xAD678846,
150 /* [107] */ 0xDA60B8D0,
151 /* [108] */ 0x44042D73,
152 /* [109] */ 0x33031DE5,
153 /* [110] */ 0xAA0A4C5F,
154 /* [111] */ 0xDD0D7CC9,
155 /* [112] */ 0x5005713C,
156 /* [113] */ 0x270241AA,
157 /* [114] */ 0xBE0B1010,
158 /* [115] */ 0xC90C2086,
159 /* [116] */ 0x5768B525,
160 /* [117] */ 0x206F85B3,
161 /* [118] */ 0xB966D409,
162 /* [119] */ 0xCE61E49F,
163 /* [120] */ 0x5EDEF90E,
164 /* [121] */ 0x29D9C998,
165 /* [122] */ 0xB0D09822,
166 /* [123] */ 0xC7D7A8B4,
167 /* [124] */ 0x59B33D17,
168 /* [125] */ 0x2EB40D81,
169 /* [126] */ 0xB7BD5C3B,
170 /* [127] */ 0xC0BA6CAD,
171 /* [128] */ 0xEDB88320,
172 /* [129] */ 0x9ABFB3B6,
173 /* [130] */ 0x03B6E20C,
174 /* [131] */ 0x74B1D29A,
175 /* [132] */ 0xEAD54739,
176 /* [133] */ 0x9DD277AF,
177 /* [134] */ 0x04DB2615,
178 /* [135] */ 0x73DC1683,
179 /* [136] */ 0xE3630B12,
180 /* [137] */ 0x94643B84,
181 /* [138] */ 0x0D6D6A3E,
182 /* [139] */ 0x7A6A5AA8,
183 /* [140] */ 0xE40ECF0B,
184 /* [141] */ 0x9309FF9D,
185 /* [142] */ 0x0A00AE27,
186 /* [143] */ 0x7D079EB1,
187 /* [144] */ 0xF00F9344,
188 /* [145] */ 0x8708A3D2,
189 /* [146] */ 0x1E01F268,
190 /* [147] */ 0x6906C2FE,
191 /* [148] */ 0xF762575D,
192 /* [149] */ 0x806567CB,
193 /* [150] */ 0x196C3671,
194 /* [151] */ 0x6E6B06E7,
195 /* [152] */ 0xFED41B76,
196 /* [153] */ 0x89D32BE0,
197 /* [154] */ 0x10DA7A5A,
198 /* [155] */ 0x67DD4ACC,
199 /* [156] */ 0xF9B9DF6F,
200 /* [157] */ 0x8EBEEFF9,
201 /* [158] */ 0x17B7BE43,
202 /* [159] */ 0x60B08ED5,
203 /* [160] */ 0xD6D6A3E8,
204 /* [161] */ 0xA1D1937E,
205 /* [162] */ 0x38D8C2C4,
206 /* [163] */ 0x4FDFF252,
207 /* [164] */ 0xD1BB67F1,
208 /* [165] */ 0xA6BC5767,
209 /* [166] */ 0x3FB506DD,
210 /* [167] */ 0x48B2364B,
211 /* [168] */ 0xD80D2BDA,
212 /* [169] */ 0xAF0A1B4C,
213 /* [170] */ 0x36034AF6,
214 /* [171] */ 0x41047A60,
215 /* [172] */ 0xDF60EFC3,
216 /* [173] */ 0xA867DF55,
217 /* [174] */ 0x316E8EEF,
218 /* [175] */ 0x4669BE79,
219 /* [176] */ 0xCB61B38C,
220 /* [177] */ 0xBC66831A,
221 /* [178] */ 0x256FD2A0,
222 /* [179] */ 0x5268E236,
223 /* [180] */ 0xCC0C7795,
224 /* [181] */ 0xBB0B4703,
225 /* [182] */ 0x220216B9,
226 /* [183] */ 0x5505262F,
227 /* [184] */ 0xC5BA3BBE,
228 /* [185] */ 0xB2BD0B28,
229 /* [186] */ 0x2BB45A92,
230 /* [187] */ 0x5CB36A04,
231 /* [188] */ 0xC2D7FFA7,
232 /* [189] */ 0xB5D0CF31,
233 /* [190] */ 0x2CD99E8B,
234 /* [191] */ 0x5BDEAE1D,
235 /* [192] */ 0x9B64C2B0,
236 /* [193] */ 0xEC63F226,
237 /* [194] */ 0x756AA39C,
238 /* [195] */ 0x026D930A,
239 /* [196] */ 0x9C0906A9,
240 /* [197] */ 0xEB0E363F,
241 /* [198] */ 0x72076785,
242 /* [199] */ 0x05005713,
243 /* [200] */ 0x95BF4A82,
244 /* [201] */ 0xE2B87A14,
245 /* [202] */ 0x7BB12BAE,
246 /* [203] */ 0x0CB61B38,
247 /* [204] */ 0x92D28E9B,
248 /* [205] */ 0xE5D5BE0D,
249 /* [206] */ 0x7CDCEFB7,
250 /* [207] */ 0x0BDBDF21,
251 /* [208] */ 0x86D3D2D4,
252 /* [209] */ 0xF1D4E242,
253 /* [210] */ 0x68DDB3F8,
254 /* [211] */ 0x1FDA836E,
255 /* [212] */ 0x81BE16CD,
256 /* [213] */ 0xF6B9265B,
257 /* [214] */ 0x6FB077E1,
258 /* [215] */ 0x18B74777,
259 /* [216] */ 0x88085AE6,
260 /* [217] */ 0xFF0F6A70,
261 /* [218] */ 0x66063BCA,
262 /* [219] */ 0x11010B5C,
263 /* [220] */ 0x8F659EFF,
264 /* [221] */ 0xF862AE69,
265 /* [222] */ 0x616BFFD3,
266 /* [223] */ 0x166CCF45,
267 /* [224] */ 0xA00AE278,
268 /* [225] */ 0xD70DD2EE,
269 /* [226] */ 0x4E048354,
270 /* [227] */ 0x3903B3C2,
271 /* [228] */ 0xA7672661,
272 /* [229] */ 0xD06016F7,
273 /* [230] */ 0x4969474D,
274 /* [231] */ 0x3E6E77DB,
275 /* [232] */ 0xAED16A4A,
276 /* [233] */ 0xD9D65ADC,
277 /* [234] */ 0x40DF0B66,
278 /* [235] */ 0x37D83BF0,
279 /* [236] */ 0xA9BCAE53,
280 /* [237] */ 0xDEBB9EC5,
281 /* [238] */ 0x47B2CF7F,
282 /* [239] */ 0x30B5FFE9,
283 /* [240] */ 0xBDBDF21C,
284 /* [241] */ 0xCABAC28A,
285 /* [242] */ 0x53B39330,
286 /* [243] */ 0x24B4A3A6,
287 /* [244] */ 0xBAD03605,
288 /* [245] */ 0xCDD70693,
289 /* [246] */ 0x54DE5729,
290 /* [247] */ 0x23D967BF,
291 /* [248] */ 0xB3667A2E,
292 /* [249] */ 0xC4614AB8,
293 /* [250] */ 0x5D681B02,
294 /* [251] */ 0x2A6F2B94,
295 /* [252] */ 0xB40BBE37,
296 /* [253] */ 0xC30C8EA1,
297 /* [254] */ 0x5A05DF1B,
298 /* [255] */ 0x2D02EF8D
299 };
300
301 //It is known that the XOR of all of the table values above is 0,
302 //and that the sum is 0xFFFFFF80. This is used to check the table
303 //for corruption on demand.
304 #define CRCHASHFUNCS_CRC32TABLE_XOR (0x00000000)
305 #define CRCHASHFUNCS_CRC32TABLE_SUM (0xFFFFFF80)
306
307
308 //Rotates an unsigned int left with wraparound.
309 static unsigned CRCHASHFUNCS_Crc32RotateLeftWithWrap(unsigned arg)
310 {
311 if (arg & 0x80000000)
312 {
313 arg <<= 1;
314 arg |= (unsigned)1;
315 }
316 else
317 {
318 arg <<= 1;
319 arg &= 0xFFFFFFFE;
320 }
321
322 return(arg);
323 }
324
325
326 //Appears to swap the bits in a data value, bit 0 for bit 7, bit 1
327 //for bit 6, etc. Obtained from the Internet (Richard A. Ellingson).
328 static unsigned CRCHASHFUNCS_Crc32Reflect(unsigned ref,
329 unsigned char ch)
330 {
331 unsigned i;
332 unsigned value;
333
334 value = 0;
335
336 for (i=1; i<((unsigned)(ch+1)); i++)
337 {
338 if (ref & 1)
339 {
340 value |= (1 << (ch-i));
341 }
342 ref >>= 1;
343 }
344
345 return(value);
346 }
347
348
349 //Returns !=0 if the internal table is alright.
350 int CRCHASHFUNCS_Crc32TableCheck(void)
351 {
352 int i;
353 unsigned xor_val;
354 unsigned sum_val;
355
356 xor_val = sum_val = 0;
357
358 for (i=0; i<256; i++)
359 {
360 xor_val ^= CRCHASHFUNCS_crc32tab[i];
361 sum_val += CRCHASHFUNCS_crc32tab[i];
362 }
363
364 return((xor_val == CRCHASHFUNCS_CRC32TABLE_XOR) &&
365 (sum_val == CRCHASHFUNCS_CRC32TABLE_SUM));
366 }
367
368
369 //Initializes a CRC state struct. This will be added to, the CRC will be
370 //extracted, and the data structure will finally be closed.
371 void CRCHASHFUNCS_Crc32StateStructOpen(struct CRCHASHFUNCS_Crc32StateStruct *arg)
372 {
373 arg->crc = 0xFFFFFFFF;
374 }
375
376
377 //Adds data to the data structure.
378 void CRCHASHFUNCS_Crc32StateStructAddData(struct CRCHASHFUNCS_Crc32StateStruct *arg,
379 void *data,
380 unsigned len)
381 {
382 assert(arg != NULL);
383 assert(data != NULL);
384
385 while (len--)
386 {
387 arg->crc = (arg->crc >> 8) ^ CRCHASHFUNCS_crc32tab[((arg->crc & 0xFF) ^ *((unsigned char *)data)) & 0xFF];
388 data = (unsigned char *)data + 1;
389 }
390 }
391
392
393 unsigned CRCHASHFUNCS_Crc32Extract(struct CRCHASHFUNCS_Crc32StateStruct *arg)
394 {
395 assert(arg != NULL);
396
397 return(arg->crc ^ 0xFFFFFFFF);
398 }
399
400
401 void CRCHASHFUNCS_Crc32StateStructClose(struct CRCHASHFUNCS_Crc32StateStruct *arg)
402 {
403 assert(arg != NULL);
404
405 //Do nothing at this time.
406 }
407
408
409 //Returns version control string for file.
410 //
411 const char *CRCHASHFUNCS_cvcinfo(void)
412 {
413 return ("$Header$");
414 }
415
416
417 //Returns version control string for associated .H file.
418 //
419 const char *CRCHASHFUNCS_hvcinfo(void)
420 {
421 return (CRCHASHFUNCS_H_VERSION);
422 }
423
424 //End of crchashfuncs.c.

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