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      1 #include <stdio.h>
      2 #include "crc32c_defs.h"
      3 #include <inttypes.h>
      4 
      5 #define ENTRIES_PER_LINE 4
      6 
      7 #if CRC_LE_BITS > 8
      8 # define LE_TABLE_ROWS (CRC_LE_BITS/8)
      9 # define LE_TABLE_SIZE 256
     10 #else
     11 # define LE_TABLE_ROWS 1
     12 # define LE_TABLE_SIZE (1 << CRC_LE_BITS)
     13 #endif
     14 
     15 #if CRC_BE_BITS > 8
     16 # define BE_TABLE_ROWS (CRC_BE_BITS/8)
     17 # define BE_TABLE_SIZE 256
     18 #else
     19 # define BE_TABLE_ROWS 1
     20 # define BE_TABLE_SIZE (1 << CRC_BE_BITS)
     21 #endif
     22 
     23 static uint32_t crc32table_be[BE_TABLE_ROWS][256];
     24 static uint32_t crc32ctable_le[LE_TABLE_ROWS][256];
     25 
     26 /**
     27  * crc32init_le() - allocate and initialize LE table data
     28  *
     29  * crc is the crc of the byte i; other entries are filled in based on the
     30  * fact that crctable[i^j] = crctable[i] ^ crctable[j].
     31  *
     32  */
     33 static void crc32cinit_le(void)
     34 {
     35 	unsigned i, j;
     36 	uint32_t crc = 1;
     37 
     38 	crc32ctable_le[0][0] = 0;
     39 
     40 	for (i = LE_TABLE_SIZE >> 1; i; i >>= 1) {
     41 		crc = (crc >> 1) ^ ((crc & 1) ? CRC32C_POLY_LE : 0);
     42 		for (j = 0; j < LE_TABLE_SIZE; j += 2 * i)
     43 			crc32ctable_le[0][i + j] = crc ^ crc32ctable_le[0][j];
     44 	}
     45 	for (i = 0; i < LE_TABLE_SIZE; i++) {
     46 		crc = crc32ctable_le[0][i];
     47 		for (j = 1; j < LE_TABLE_ROWS; j++) {
     48 			crc = crc32ctable_le[0][crc & 0xff] ^ (crc >> 8);
     49 			crc32ctable_le[j][i] = crc;
     50 		}
     51 	}
     52 }
     53 
     54 /**
     55  * crc32init_be() - allocate and initialize BE table data
     56  */
     57 static void crc32init_be(void)
     58 {
     59 	unsigned i, j;
     60 	uint32_t crc = 0x80000000;
     61 
     62 	crc32table_be[0][0] = 0;
     63 
     64 	for (i = 1; i < BE_TABLE_SIZE; i <<= 1) {
     65 		crc = (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE : 0);
     66 		for (j = 0; j < i; j++)
     67 			crc32table_be[0][i + j] = crc ^ crc32table_be[0][j];
     68 	}
     69 	for (i = 0; i < BE_TABLE_SIZE; i++) {
     70 		crc = crc32table_be[0][i];
     71 		for (j = 1; j < BE_TABLE_ROWS; j++) {
     72 			crc = crc32table_be[0][(crc >> 24) & 0xff] ^ (crc << 8);
     73 			crc32table_be[j][i] = crc;
     74 		}
     75 	}
     76 }
     77 
     78 static void output_table(uint32_t (*table)[256], int rows, int len, char *trans)
     79 {
     80 	int i, j;
     81 
     82 	for (j = 0 ; j < rows; j++) {
     83 		printf("{");
     84 		for (i = 0; i < len - 1; i++) {
     85 			if (i % ENTRIES_PER_LINE == 0)
     86 				printf("\n");
     87 			printf("%s(0x%8.8xL), ", trans, table[j][i]);
     88 		}
     89 		printf("%s(0x%8.8xL)},\n", trans, table[j][len - 1]);
     90 	}
     91 }
     92 
     93 int main(int argc, char **argv)
     94 {
     95 	printf("/* this file is generated - do not edit */\n\n");
     96 
     97 	if (CRC_BE_BITS > 1) {
     98 		crc32init_be();
     99 		printf("static const uint32_t "
    100 		       "crc32table_be[%d][%d] = {",
    101 		       BE_TABLE_ROWS, BE_TABLE_SIZE);
    102 		output_table(crc32table_be, LE_TABLE_ROWS,
    103 			     BE_TABLE_SIZE, "tobe");
    104 		printf("};\n");
    105 	}
    106 	if (CRC_LE_BITS > 1) {
    107 		crc32cinit_le();
    108 		printf("static const uint32_t "
    109 		       "crc32ctable_le[%d][%d] = {",
    110 		       LE_TABLE_ROWS, LE_TABLE_SIZE);
    111 		output_table(crc32ctable_le, LE_TABLE_ROWS,
    112 			     LE_TABLE_SIZE, "tole");
    113 		printf("};\n");
    114 	}
    115 
    116 	return 0;
    117 }
    118