mirror of https://github.com/vitalif/e2fsprogs
124 lines
2.7 KiB
C
124 lines
2.7 KiB
C
#include <stdio.h>
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#include "crc32c_defs.h"
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#include <inttypes.h>
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#define ENTRIES_PER_LINE 4
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#if CRC_LE_BITS <= 8
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#define LE_TABLE_SIZE (1 << CRC_LE_BITS)
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#else
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#define LE_TABLE_SIZE 256
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#endif
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#if CRC_BE_BITS <= 8
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#define BE_TABLE_SIZE (1 << CRC_BE_BITS)
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#else
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#define BE_TABLE_SIZE 256
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#endif
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static uint32_t crc32ctable_le[8][256];
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static uint32_t crc32ctable_be[8][256];
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/**
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* crc32cinit_le() - allocate and initialize LE table data
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*
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* crc is the crc of the byte i; other entries are filled in based on the
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* fact that crctable[i^j] = crctable[i] ^ crctable[j].
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*
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*/
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static void crc32cinit_le(void)
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{
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unsigned i, j;
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uint32_t crc = 1;
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crc32ctable_le[0][0] = 0;
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for (i = LE_TABLE_SIZE >> 1; i; i >>= 1) {
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crc = (crc >> 1) ^ ((crc & 1) ? CRCPOLY_LE : 0);
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for (j = 0; j < LE_TABLE_SIZE; j += 2 * i)
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crc32ctable_le[0][i + j] = crc ^ crc32ctable_le[0][j];
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}
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for (i = 0; i < LE_TABLE_SIZE; i++) {
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crc = crc32ctable_le[0][i];
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for (j = 1; j < 8; j++) {
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crc = crc32ctable_le[0][crc & 0xff] ^ (crc >> 8);
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crc32ctable_le[j][i] = crc;
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}
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}
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}
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/**
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* crc32cinit_be() - allocate and initialize BE table data
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*/
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static void crc32cinit_be(void)
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{
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unsigned i, j;
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uint32_t crc = 0x80000000;
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crc32ctable_be[0][0] = 0;
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for (i = 1; i < BE_TABLE_SIZE; i <<= 1) {
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crc = (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE : 0);
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for (j = 0; j < i; j++)
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crc32ctable_be[0][i + j] = crc ^ crc32ctable_be[0][j];
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}
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for (i = 0; i < BE_TABLE_SIZE; i++) {
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crc = crc32ctable_be[0][i];
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for (j = 1; j < 8; j++) {
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crc = crc32ctable_be[0][(crc >> 24) & 0xff] ^
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(crc << 8);
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crc32ctable_be[j][i] = crc;
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}
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}
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}
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static void output_table(uint32_t table[8][256], int len, char trans)
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{
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int i, j;
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for (j = 0 ; j < 8; j++) {
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printf("static const uint32_t t%d_%ce[] = {", j, trans);
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for (i = 0; i < len - 1; i++) {
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if ((i % ENTRIES_PER_LINE) == 0)
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printf("\n");
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printf("to%ce(0x%8.8xL),", trans, table[j][i]);
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if ((i % ENTRIES_PER_LINE) != (ENTRIES_PER_LINE - 1))
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printf(" ");
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}
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printf("to%ce(0x%8.8xL)};\n\n", trans, table[j][len - 1]);
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if (trans == 'l') {
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if ((j+1)*8 >= CRC_LE_BITS)
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break;
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} else {
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if ((j+1)*8 >= CRC_BE_BITS)
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break;
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}
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}
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}
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int main(int argc, char **argv)
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{
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printf("/*\n");
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printf(" * crc32ctable.h - CRC32c tables\n");
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printf(" * this file is generated - do not edit\n");
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printf(" * # gen_crc32ctable > crc32c_table.h\n");
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printf(" * with\n");
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printf(" * CRC_LE_BITS = %d\n", CRC_LE_BITS);
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printf(" * CRC_BE_BITS = %d\n", CRC_BE_BITS);
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printf(" */\n");
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printf("#include <stdint.h>\n");
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if (CRC_LE_BITS > 1) {
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crc32cinit_le();
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output_table(crc32ctable_le, LE_TABLE_SIZE, 'l');
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}
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if (CRC_BE_BITS > 1) {
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crc32cinit_be();
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output_table(crc32ctable_be, BE_TABLE_SIZE, 'b');
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}
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return 0;
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}
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