| * CRC32 using the polynomial from IEEE-802.3 |
| * Authors: Lasse Collin <lasse.collin@tukaani.org> |
| * Igor Pavlov <https://7-zip.org/> |
| * This file has been put into the public domain. |
| * You can do whatever you want with this file. |
| * This is not the fastest implementation, but it is pretty compact. |
| * The fastest versions of xz_crc32() on modern CPUs without hardware |
| * accelerated CRC instruction are 3-5 times as fast as this version, |
| * but they are bigger and use more memory for the lookup table. |
| * STATIC_RW_DATA is used in the pre-boot environment on some architectures. |
| * See <linux/decompress/mm.h> for details. |
| # define STATIC_RW_DATA static |
| STATIC_RW_DATA uint32_t xz_crc32_table[256]; |
| XZ_EXTERN void xz_crc32_init(void) |
| const uint32_t poly = CRC32_POLY_LE; |
| for (i = 0; i < 256; ++i) { |
| r = (r >> 1) ^ (poly & ~((r & 1) - 1)); |
| XZ_EXTERN uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc) |
| crc = xz_crc32_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8); |