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| 1 //----------------------------------------------------------------------------- |
| 2 // Low level CRC functions for use by crcmod. This version is the C |
| 3 // implementation that corresponds to the Python module _crcfunpy. This module |
| 4 // will be used by crcmod if it is built for the target platform. Otherwise, |
| 5 // the Python module is used. |
| 6 // |
| 7 // Copyright (c) 2004 Raymond L. Buvel |
| 8 // |
| 9 // Permission is hereby granted, free of charge, to any person obtaining a copy |
| 10 // of this software and associated documentation files (the "Software"), to |
| 11 // deal in the Software without restriction, including without limitation the |
| 12 // rights to use, copy, modify, merge, publish, distribute, sublicense, and/or |
| 13 // sell copies of the Software, and to permit persons to whom the Software is |
| 14 // furnished to do so, subject to the following conditions: |
| 15 // |
| 16 // The above copyright notice and this permission notice shall be included in |
| 17 // all 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 |
| 24 // FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS |
| 25 // IN THE SOFTWARE. |
| 26 //----------------------------------------------------------------------------- |
| 27 |
| 28 // Force Py_ssize_t to be used for s# conversions. |
| 29 #define PY_SSIZE_T_CLEAN |
| 30 #include <Python.h> |
| 31 |
| 32 // Make compatible with previous Python versions |
| 33 #if PY_VERSION_HEX < 0x02050000 |
| 34 typedef int Py_ssize_t; |
| 35 #define PY_SSIZE_T_MAX INT_MAX |
| 36 #define PY_SSIZE_T_MIN INT_MIN |
| 37 #endif |
| 38 |
| 39 // Note: the type declarations are set up to work on 32-bit platforms using the |
| 40 // GNU C compiler. They will need to be adjusted for other platforms. In |
| 41 // particular, the Microsoft Windows compiler uses _int64 instead of long long. |
| 42 |
| 43 // Define a few types to make it easier to port to other platforms. |
| 44 typedef unsigned char UINT8; |
| 45 typedef unsigned short UINT16; |
| 46 typedef unsigned int UINT32; |
| 47 typedef unsigned long long UINT64; |
| 48 |
| 49 // Define some macros for the data format strings. The INPUT strings are for |
| 50 // decoding the input parameters to the function which are (data, crc, table). |
| 51 |
| 52 // Note: these format strings use codes that are new in Python 2.3 so it would |
| 53 // be necessary to rewrite the code for versions earlier than 2.3. |
| 54 |
| 55 #define INPUT8 "s#Bs#" |
| 56 #define INPUT16 "s#Hs#" |
| 57 #define INPUT32 "s#Is#" |
| 58 #define INPUT64 "s#Ks#" |
| 59 |
| 60 // Define some macros that extract the specified byte from an integral value in |
| 61 // what should be a platform independent manner. |
| 62 #define BYTE0(x) ((UINT8)(x)) |
| 63 #define BYTE1(x) ((UINT8)((x) >> 8)) |
| 64 #define BYTE2(x) ((UINT8)((x) >> 16)) |
| 65 #define BYTE3(x) ((UINT8)((x) >> 24)) |
| 66 #define BYTE7(x) ((UINT8)((x) >> 56)) |
| 67 |
| 68 //----------------------------------------------------------------------------- |
| 69 // Compute a 8-bit crc over the input data. |
| 70 // Inputs: |
| 71 // data - string containing the data |
| 72 // crc - unsigned integer containing the initial crc |
| 73 // table - string containing the 8-bit table corresponding to the generator |
| 74 // polynomial. |
| 75 // Returns: |
| 76 // crc - unsigned integer containing the resulting crc |
| 77 |
| 78 static PyObject* |
| 79 _crc8(PyObject* self, PyObject* args) |
| 80 { |
| 81 UINT8 crc; |
| 82 UINT8* data; |
| 83 Py_ssize_t dataLen; |
| 84 UINT8* table; |
| 85 Py_ssize_t tableLen; |
| 86 |
| 87 if (!PyArg_ParseTuple(args, INPUT8, &data, &dataLen, &crc, |
| 88 &table, &tableLen)) |
| 89 { |
| 90 return NULL; |
| 91 } |
| 92 |
| 93 if (tableLen != 256) |
| 94 { |
| 95 PyErr_SetString(PyExc_ValueError, "invalid CRC table"); |
| 96 return NULL; |
| 97 } |
| 98 |
| 99 while (dataLen--) |
| 100 { |
| 101 crc = table[*data ^ crc]; |
| 102 data++; |
| 103 } |
| 104 |
| 105 return PyInt_FromLong((long)crc); |
| 106 } |
| 107 |
| 108 //----------------------------------------------------------------------------- |
| 109 // Compute a 8-bit crc over the input data. The data stream is bit reversed |
| 110 // during the computation. |
| 111 // Inputs: |
| 112 // data - string containing the data |
| 113 // crc - unsigned integer containing the initial crc |
| 114 // table - string containing the 8-bit table corresponding to the generator |
| 115 // polynomial. |
| 116 // Returns: |
| 117 // crc - unsigned integer containing the resulting crc |
| 118 |
| 119 static PyObject* |
| 120 _crc8r(PyObject* self, PyObject* args) |
| 121 { |
| 122 UINT8 crc; |
| 123 UINT8* data; |
| 124 Py_ssize_t dataLen; |
| 125 UINT8* table; |
| 126 Py_ssize_t tableLen; |
| 127 |
| 128 if (!PyArg_ParseTuple(args, INPUT8, &data, &dataLen, &crc, |
| 129 &table, &tableLen)) |
| 130 { |
| 131 return NULL; |
| 132 } |
| 133 |
| 134 if (tableLen != 256) |
| 135 { |
| 136 PyErr_SetString(PyExc_ValueError, "invalid CRC table"); |
| 137 return NULL; |
| 138 } |
| 139 |
| 140 while (dataLen--) |
| 141 { |
| 142 crc = table[*data ^ crc]; |
| 143 data++; |
| 144 } |
| 145 |
| 146 return PyInt_FromLong((long)crc); |
| 147 } |
| 148 |
| 149 //----------------------------------------------------------------------------- |
| 150 // Compute a 16-bit crc over the input data. |
| 151 // Inputs: |
| 152 // data - string containing the data |
| 153 // crc - unsigned integer containing the initial crc |
| 154 // table - string containing the 16-bit table corresponding to the generator |
| 155 // polynomial. |
| 156 // Returns: |
| 157 // crc - unsigned integer containing the resulting crc |
| 158 |
| 159 static PyObject* |
| 160 _crc16(PyObject* self, PyObject* args) |
| 161 { |
| 162 UINT16 crc; |
| 163 UINT8* data; |
| 164 Py_ssize_t dataLen; |
| 165 UINT16* table; |
| 166 Py_ssize_t tableLen; |
| 167 |
| 168 if (!PyArg_ParseTuple(args, INPUT16, &data, &dataLen, &crc, |
| 169 &table, &tableLen)) |
| 170 { |
| 171 return NULL; |
| 172 } |
| 173 |
| 174 if (tableLen != 256*2) |
| 175 { |
| 176 PyErr_SetString(PyExc_ValueError, "invalid CRC table"); |
| 177 return NULL; |
| 178 } |
| 179 |
| 180 while (dataLen--) |
| 181 { |
| 182 crc = table[*data ^ BYTE1(crc)] ^ (crc << 8); |
| 183 data++; |
| 184 } |
| 185 |
| 186 return PyInt_FromLong((long)crc); |
| 187 } |
| 188 |
| 189 //----------------------------------------------------------------------------- |
| 190 // Compute a 16-bit crc over the input data. The data stream is bit reversed |
| 191 // during the computation. |
| 192 // Inputs: |
| 193 // data - string containing the data |
| 194 // crc - unsigned integer containing the initial crc |
| 195 // table - string containing the 16-bit table corresponding to the generator |
| 196 // polynomial. |
| 197 // Returns: |
| 198 // crc - unsigned integer containing the resulting crc |
| 199 |
| 200 static PyObject* |
| 201 _crc16r(PyObject* self, PyObject* args) |
| 202 { |
| 203 UINT16 crc; |
| 204 UINT8* data; |
| 205 Py_ssize_t dataLen; |
| 206 UINT16* table; |
| 207 Py_ssize_t tableLen; |
| 208 |
| 209 if (!PyArg_ParseTuple(args, INPUT16, &data, &dataLen, &crc, |
| 210 &table, &tableLen)) |
| 211 { |
| 212 return NULL; |
| 213 } |
| 214 |
| 215 if (tableLen != 256*2) |
| 216 { |
| 217 PyErr_SetString(PyExc_ValueError, "invalid CRC table"); |
| 218 return NULL; |
| 219 } |
| 220 |
| 221 while (dataLen--) |
| 222 { |
| 223 crc = table[*data ^ BYTE0(crc)] ^ (crc >> 8); |
| 224 data++; |
| 225 } |
| 226 |
| 227 return PyInt_FromLong((long)crc); |
| 228 } |
| 229 |
| 230 //----------------------------------------------------------------------------- |
| 231 // Compute a 24-bit crc over the input data. |
| 232 // Inputs: |
| 233 // data - string containing the data |
| 234 // crc - unsigned integer containing the initial crc |
| 235 // table - string containing the 24-bit table corresponding to the generator |
| 236 // polynomial. |
| 237 // Returns: |
| 238 // crc - unsigned integer containing the resulting crc |
| 239 |
| 240 static PyObject* |
| 241 _crc24(PyObject* self, PyObject* args) |
| 242 { |
| 243 UINT32 crc; |
| 244 UINT8* data; |
| 245 Py_ssize_t dataLen; |
| 246 UINT32* table; |
| 247 Py_ssize_t tableLen; |
| 248 |
| 249 if (!PyArg_ParseTuple(args, INPUT32, &data, &dataLen, &crc, |
| 250 &table, &tableLen)) |
| 251 { |
| 252 return NULL; |
| 253 } |
| 254 |
| 255 if (tableLen != 256*4) |
| 256 { |
| 257 PyErr_SetString(PyExc_ValueError, "invalid CRC table"); |
| 258 return NULL; |
| 259 } |
| 260 |
| 261 while (dataLen--) |
| 262 { |
| 263 crc = table[*data ^ BYTE2(crc)] ^ (crc << 8); |
| 264 data++; |
| 265 } |
| 266 |
| 267 return PyInt_FromLong((long)(crc & 0xFFFFFFU)); |
| 268 } |
| 269 |
| 270 //----------------------------------------------------------------------------- |
| 271 // Compute a 24-bit crc over the input data. The data stream is bit reversed |
| 272 // during the computation. |
| 273 // Inputs: |
| 274 // data - string containing the data |
| 275 // crc - unsigned integer containing the initial crc |
| 276 // table - string containing the 24-bit table corresponding to the generator |
| 277 // polynomial. |
| 278 // Returns: |
| 279 // crc - unsigned integer containing the resulting crc |
| 280 |
| 281 static PyObject* |
| 282 _crc24r(PyObject* self, PyObject* args) |
| 283 { |
| 284 UINT32 crc; |
| 285 UINT8* data; |
| 286 Py_ssize_t dataLen; |
| 287 UINT32* table; |
| 288 Py_ssize_t tableLen; |
| 289 |
| 290 if (!PyArg_ParseTuple(args, INPUT32, &data, &dataLen, &crc, |
| 291 &table, &tableLen)) |
| 292 { |
| 293 return NULL; |
| 294 } |
| 295 |
| 296 if (tableLen != 256*4) |
| 297 { |
| 298 PyErr_SetString(PyExc_ValueError, "invalid CRC table"); |
| 299 return NULL; |
| 300 } |
| 301 |
| 302 crc = crc & 0xFFFFFFU; |
| 303 while (dataLen--) |
| 304 { |
| 305 crc = table[*data ^ BYTE0(crc)] ^ (crc >> 8); |
| 306 data++; |
| 307 } |
| 308 |
| 309 return PyInt_FromLong((long)crc); |
| 310 } |
| 311 |
| 312 //----------------------------------------------------------------------------- |
| 313 // Compute a 32-bit crc over the input data. |
| 314 // Inputs: |
| 315 // data - string containing the data |
| 316 // crc - unsigned integer containing the initial crc |
| 317 // table - string containing the 32-bit table corresponding to the generator |
| 318 // polynomial. |
| 319 // Returns: |
| 320 // crc - unsigned integer containing the resulting crc |
| 321 |
| 322 static PyObject* |
| 323 _crc32(PyObject* self, PyObject* args) |
| 324 { |
| 325 UINT32 crc; |
| 326 UINT8* data; |
| 327 Py_ssize_t dataLen; |
| 328 UINT32* table; |
| 329 Py_ssize_t tableLen; |
| 330 |
| 331 if (!PyArg_ParseTuple(args, INPUT32, &data, &dataLen, &crc, |
| 332 &table, &tableLen)) |
| 333 { |
| 334 return NULL; |
| 335 } |
| 336 |
| 337 if (tableLen != 256*4) |
| 338 { |
| 339 PyErr_SetString(PyExc_ValueError, "invalid CRC table"); |
| 340 return NULL; |
| 341 } |
| 342 |
| 343 while (dataLen--) |
| 344 { |
| 345 crc = table[*data ^ BYTE3(crc)] ^ (crc << 8); |
| 346 data++; |
| 347 } |
| 348 |
| 349 return PyLong_FromUnsignedLong(crc); |
| 350 } |
| 351 |
| 352 //----------------------------------------------------------------------------- |
| 353 // Compute a 32-bit crc over the input data. The data stream is bit reversed |
| 354 // during the computation. |
| 355 // Inputs: |
| 356 // data - string containing the data |
| 357 // crc - unsigned integer containing the initial crc |
| 358 // table - string containing the 32-bit table corresponding to the generator |
| 359 // polynomial. |
| 360 // Returns: |
| 361 // crc - unsigned integer containing the resulting crc |
| 362 |
| 363 static PyObject* |
| 364 _crc32r(PyObject* self, PyObject* args) |
| 365 { |
| 366 UINT32 crc; |
| 367 UINT8* data; |
| 368 Py_ssize_t dataLen; |
| 369 UINT32* table; |
| 370 Py_ssize_t tableLen; |
| 371 |
| 372 if (!PyArg_ParseTuple(args, INPUT32, &data, &dataLen, &crc, |
| 373 &table, &tableLen)) |
| 374 { |
| 375 return NULL; |
| 376 } |
| 377 |
| 378 if (tableLen != 256*4) |
| 379 { |
| 380 PyErr_SetString(PyExc_ValueError, "invalid CRC table"); |
| 381 return NULL; |
| 382 } |
| 383 |
| 384 while (dataLen--) |
| 385 { |
| 386 crc = table[*data ^ BYTE0(crc)] ^ (crc >> 8); |
| 387 data++; |
| 388 } |
| 389 |
| 390 return PyLong_FromUnsignedLong(crc); |
| 391 } |
| 392 |
| 393 //----------------------------------------------------------------------------- |
| 394 // Compute a 64-bit crc over the input data. |
| 395 // Inputs: |
| 396 // data - string containing the data |
| 397 // crc - unsigned integer containing the initial crc |
| 398 // table - string containing the 64-bit table corresponding to the generator |
| 399 // polynomial. |
| 400 // Returns: |
| 401 // crc - unsigned integer containing the resulting crc |
| 402 |
| 403 static PyObject* |
| 404 _crc64(PyObject* self, PyObject* args) |
| 405 { |
| 406 UINT64 crc; |
| 407 UINT8* data; |
| 408 Py_ssize_t dataLen; |
| 409 UINT64* table; |
| 410 Py_ssize_t tableLen; |
| 411 |
| 412 if (!PyArg_ParseTuple(args, INPUT64, &data, &dataLen, &crc, |
| 413 &table, &tableLen)) |
| 414 { |
| 415 return NULL; |
| 416 } |
| 417 |
| 418 if (tableLen != 256*8) |
| 419 { |
| 420 PyErr_SetString(PyExc_ValueError, "invalid CRC table"); |
| 421 return NULL; |
| 422 } |
| 423 |
| 424 while (dataLen--) |
| 425 { |
| 426 crc = table[*data ^ BYTE7(crc)] ^ (crc << 8); |
| 427 data++; |
| 428 } |
| 429 |
| 430 return PyLong_FromUnsignedLongLong(crc); |
| 431 } |
| 432 |
| 433 //----------------------------------------------------------------------------- |
| 434 // Compute a 64-bit crc over the input data. The data stream is bit reversed |
| 435 // during the computation. |
| 436 // Inputs: |
| 437 // data - string containing the data |
| 438 // crc - unsigned integer containing the initial crc |
| 439 // table - string containing the 64-bit table corresponding to the generator |
| 440 // polynomial. |
| 441 // Returns: |
| 442 // crc - unsigned integer containing the resulting crc |
| 443 |
| 444 static PyObject* |
| 445 _crc64r(PyObject* self, PyObject* args) |
| 446 { |
| 447 UINT64 crc; |
| 448 UINT8* data; |
| 449 Py_ssize_t dataLen; |
| 450 UINT64* table; |
| 451 Py_ssize_t tableLen; |
| 452 |
| 453 if (!PyArg_ParseTuple(args, INPUT64, &data, &dataLen, &crc, |
| 454 &table, &tableLen)) |
| 455 { |
| 456 return NULL; |
| 457 } |
| 458 |
| 459 if (tableLen != 256*8) |
| 460 { |
| 461 PyErr_SetString(PyExc_ValueError, "invalid CRC table"); |
| 462 return NULL; |
| 463 } |
| 464 |
| 465 while (dataLen--) |
| 466 { |
| 467 crc = table[*data ^ BYTE0(crc)] ^ (crc >> 8); |
| 468 data++; |
| 469 } |
| 470 |
| 471 return PyLong_FromUnsignedLongLong(crc); |
| 472 } |
| 473 |
| 474 //----------------------------------------------------------------------------- |
| 475 static PyMethodDef methodTable[] = { |
| 476 {"_crc8", _crc8, METH_VARARGS}, |
| 477 {"_crc8r", _crc8r, METH_VARARGS}, |
| 478 {"_crc16", _crc16, METH_VARARGS}, |
| 479 {"_crc16r", _crc16r, METH_VARARGS}, |
| 480 {"_crc24", _crc24, METH_VARARGS}, |
| 481 {"_crc24r", _crc24r, METH_VARARGS}, |
| 482 {"_crc32", _crc32, METH_VARARGS}, |
| 483 {"_crc32r", _crc32r, METH_VARARGS}, |
| 484 {"_crc64", _crc64, METH_VARARGS}, |
| 485 {"_crc64r", _crc64r, METH_VARARGS}, |
| 486 {NULL, NULL} |
| 487 }; |
| 488 |
| 489 //----------------------------------------------------------------------------- |
| 490 void init_crcfunext(void) |
| 491 { |
| 492 PyObject *m; |
| 493 |
| 494 if ((sizeof(UINT8) != 1) || (sizeof(UINT16) != 2) || |
| 495 (sizeof(UINT32) != 4) || (sizeof(UINT64) != 8)) |
| 496 { |
| 497 Py_FatalError("crcfunext: One of the data types is invalid"); |
| 498 } |
| 499 m = Py_InitModule("_crcfunext", methodTable); |
| 500 } |
| 501 |
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