crc32_small.c File Reference

CRC32 calculation (size-optimized) More...

#include "check.h"

Go to the source code of this file.

Functions
static void	crc32_init (void)
void	lzma_crc32_init (void)
	LZMA_API (uint32_t)

Variables
uint32_t	lzma_crc32_table [1][256]

Detailed Description

CRC32 calculation (size-optimized)

Definition in file crc32_small.c.

Function Documentation

crc32_init()

static void crc32_init ( void  )

static

Definition at line 20 of file crc32_small.c.

{
    static const uint32_t poly32 = UINT32_C(0xEDB88320);
 
    for (size_t b = 0; b < 256; ++b) {
        uint32_t r = b;
        for (size_t i = 0; i < 8; ++i) {
            if (r & 1)
                r = (r >> 1) ^ poly32;
            else
                r >>= 1;
        }
 
        lzma_crc32_table[0][b] = r;
    }
 
    return;
}

References b, i, lzma_crc32_table, r, and UINT32_C.

Referenced by lzma_crc32_init().

LZMA_API()

LZMA_API

(

uint32_t

)

Definition at line 48 of file crc32_small.c.

{
    lzma_crc32_init();
 
    crc = ~crc;
 
    while (size != 0) {
        crc = lzma_crc32_table[0][*buf++ ^ (crc & 0xFF)] ^ (crc >> 8);
        --size;
    }
 
    return ~crc;
}

References lzma_crc32_init(), and lzma_crc32_table.

lzma_crc32_init()

void lzma_crc32_init

(

void

)

Definition at line 41 of file crc32_small.c.

{
    mythread_once(crc32_init);
    return;
}

References crc32_init(), and mythread_once.

Referenced by LZMA_API(), and lzma_lz_encoder_init().

Variable Documentation

lzma_crc32_table

uint32_t lzma_crc32_table[1][256]

lzma_crc32_table[0] is needed by LZ encoder so we need to keep the array two-dimensional.

Definition at line 16 of file crc32_small.c.

Referenced by crc32_init(), and LZMA_API().