crc32.c File Reference

#include "unarr-imp.h"

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Functions
uint32_t	ar_crc32 (uint32_t crc32, const unsigned char *data, size_t data_len)

Variables
static bool	crc_table_ready = false
static uint32_t	crc_table [256]

Function Documentation

uint32_t ar_crc32	(	uint32_t	crc32,
		const unsigned char *	data,
		size_t	data_len
	)

Definition at line 13 of file crc32.c.

{
    if (!crc_table_ready) {
        uint32_t i, j;
        uint32_t h = 1;
        crc_table[0] = 0;
        for (i = 128; i; i >>= 1) {
            h = (h >> 1) ^ ((h & 1) ? 0xEDB88320 : 0);
            for (j = 0; j < 256; j += 2 * i) {
                crc_table[i + j] = crc_table[j] ^ h;
            }
        }
        crc_table_ready = true;
    }

    crc32 = crc32 ^ 0xFFFFFFFF;
    while (data_len-- > 0) {
        crc32 = (crc32 >> 8) ^ crc_table[(crc32 ^ *data++) & 0xFF];
    }
    return crc32 ^ 0xFFFFFFFF;
}

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Variable Documentation

uint32_t crc_table[256]

static

Definition at line 11 of file crc32.c.

bool crc_table_ready = false

static

Definition at line 10 of file crc32.c.