FreeBSD/Linux Kernel Cross Reference
sys/contrib/xz-embedded/linux/lib/xz/xz_crc32.c

     /*
      * 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.
     */
    
    #include "xz_private.h"
    
    /*
     * STATIC_RW_DATA is used in the pre-boot environment on some architectures.
     * See <linux/decompress/mm.h> for details.
     */
    #ifndef STATIC_RW_DATA
    #       define STATIC_RW_DATA static
    #endif
    
    STATIC_RW_DATA uint32_t xz_crc32_table[256];
    
    XZ_EXTERN void xz_crc32_init(void)
    {
            const uint32_t poly = 0xEDB88320;
    
            uint32_t i;
            uint32_t j;
            uint32_t r;
    
            for (i = 0; i < 256; ++i) {
                    r = i;
                    for (j = 0; j < 8; ++j)
                            r = (r >> 1) ^ (poly & ~((r & 1) - 1));
    
                    xz_crc32_table[i] = r;
            }
    
            return;
    }
    
    XZ_EXTERN uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc)
    {
            crc = ~crc;
    
            while (size != 0) {
                    crc = xz_crc32_table[*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
                    --size;
            }
    
            return ~crc;
    }

Cache object: 4fa5de9bb433ccf1200ac95cd38f5ff9