crc32.cc File Reference

#include "zutil.h"
#include "crc32.h"

Go to the source code of this file.

Macros
#define	local   static
#define	TBLS   1
#define	DO1   crc = crc_table[0][((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8)
#define	DO8   DO1; DO1; DO1; DO1; DO1; DO1; DO1; DO1

Functions
const unsigned long FAR *ZEXPORT	get_crc_table ()
unsigned long ZEXPORT	crc32 (unsigned long crc, const unsigned char FAR *buf, unsigned len)

Macro Definition Documentation

DO1

#define DO1   crc = crc_table[0][((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8)

Definition at line 209 of file crc32.cc.

DO8

#define DO8   DO1; DO1; DO1; DO1; DO1; DO1; DO1; DO1

Definition at line 210 of file crc32.cc.

local

#define local   static

Definition at line 31 of file crc32.cc.

TBLS

#define TBLS   1

Definition at line 64 of file crc32.cc.

Function Documentation

crc32()

unsigned long ZEXPORT crc32	(	unsigned long	crc,
		const unsigned char FAR *	buf,
		unsigned	len
	)

Definition at line 213 of file crc32.cc.

{
    if (buf == Z_NULL) return 0UL;
 
#ifdef DYNAMIC_CRC_TABLE
    if (crc_table_empty)
        make_crc_table();
#endif /* DYNAMIC_CRC_TABLE */
 
#ifdef BYFOUR
    if (sizeof(void *) == sizeof(ptrdiff_t)) {
        u4 endian;
 
        endian = 1;
        if (*((unsigned char *)(&endian)))
            return crc32_little(crc, buf, len);
        else
            return crc32_big(crc, buf, len);
    }
#endif /* BYFOUR */
    crc = crc ^ 0xffffffffUL;
    while (len >= 8) {
        DO8;
        len -= 8;
    }
    if (len) do {
        DO1;
    } while (--len);
    return crc ^ 0xffffffffUL;
}

Referenced by deflate(), deflateReset(), and read_buf().

get_crc_table()

const unsigned long FAR *ZEXPORT get_crc_table

(

)

Definition at line 199 of file crc32.cc.

{
#ifdef DYNAMIC_CRC_TABLE
    if (crc_table_empty)
        make_crc_table();
#endif /* DYNAMIC_CRC_TABLE */
    return (const unsigned long FAR *)crc_table;
}