120 строки
3.0 KiB
C
120 строки
3.0 KiB
C
|
/* zutil.h -- internal interface and configuration of the compression library
|
||
|
|
* Copyright (C) 1995-1998 Jean-loup Gailly.
|
||
|
|
* For conditions of distribution and use, see copyright notice in zlib.h
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* WARNING: this file should *not* be used by applications. It is
|
||
|
|
part of the implementation of the compression library and is
|
||
|
|
subject to change. Applications should only use zlib.h.
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* @(#) $Id: zutil.h,v 1.1 2000/01/01 03:32:23 davem Exp $ */
|
||
|
|
|
||
|
|
#ifndef _Z_UTIL_H
|
||
|
|
#define _Z_UTIL_H
|
||
|
|
|
||
|
|
#include <linux/zlib.h>
|
||
|
|
#include <linux/string.h>
|
||
|
|
#include <linux/errno.h>
|
||
|
|
#include <linux/kernel.h>
|
||
|
|
|
||
|
|
typedef unsigned char uch;
|
||
|
|
typedef unsigned short ush;
|
||
|
|
typedef unsigned long ulg;
|
||
|
|
|
||
|
|
/* common constants */
|
||
|
|
|
||
|
|
#ifndef DEF_WBITS
|
||
|
|
# define DEF_WBITS MAX_WBITS
|
||
|
|
#endif
|
||
|
|
/* default windowBits for decompression. MAX_WBITS is for compression only */
|
||
|
|
|
||
|
|
#if MAX_MEM_LEVEL >= 8
|
||
|
|
# define DEF_MEM_LEVEL 8
|
||
|
|
#else
|
||
|
|
# define DEF_MEM_LEVEL MAX_MEM_LEVEL
|
||
|
|
#endif
|
||
|
|
/* default memLevel */
|
||
|
|
|
||
|
|
#define STORED_BLOCK 0
|
||
|
|
#define STATIC_TREES 1
|
||
|
|
#define DYN_TREES 2
|
||
|
|
/* The three kinds of block type */
|
||
|
|
|
||
|
|
#define MIN_MATCH 3
|
||
|
|
#define MAX_MATCH 258
|
||
|
|
/* The minimum and maximum match lengths */
|
||
|
|
|
||
|
|
#define PRESET_DICT 0x20 /* preset dictionary flag in zlib header */
|
||
|
|
|
||
|
|
/* target dependencies */
|
||
|
|
|
||
|
|
/* Common defaults */
|
||
|
|
|
||
|
|
#ifndef OS_CODE
|
||
|
|
# define OS_CODE 0x03 /* assume Unix */
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/* functions */
|
||
|
|
|
||
|
|
typedef uLong (*check_func) (uLong check, const Byte *buf,
|
||
|
|
uInt len);
|
||
|
|
|
||
|
|
|
||
|
|
/* checksum functions */
|
||
|
|
|
||
|
|
#define BASE 65521L /* largest prime smaller than 65536 */
|
||
|
|
#define NMAX 5552
|
||
|
|
/* NMAX is the largest n such that 255n(n+1)/2 + (n+1)(BASE-1) <= 2^32-1 */
|
||
|
|
|
||
|
|
#define DO1(buf,i) {s1 += buf[i]; s2 += s1;}
|
||
|
|
#define DO2(buf,i) DO1(buf,i); DO1(buf,i+1);
|
||
|
|
#define DO4(buf,i) DO2(buf,i); DO2(buf,i+2);
|
||
|
|
#define DO8(buf,i) DO4(buf,i); DO4(buf,i+4);
|
||
|
|
#define DO16(buf) DO8(buf,0); DO8(buf,8);
|
||
|
|
|
||
|
|
/* ========================================================================= */
|
||
|
|
/*
|
||
|
|
Update a running Adler-32 checksum with the bytes buf[0..len-1] and
|
||
|
|
return the updated checksum. If buf is NULL, this function returns
|
||
|
|
the required initial value for the checksum.
|
||
|
|
An Adler-32 checksum is almost as reliable as a CRC32 but can be computed
|
||
|
|
much faster. Usage example:
|
||
|
|
|
||
|
|
uLong adler = adler32(0L, NULL, 0);
|
||
|
|
|
||
|
|
while (read_buffer(buffer, length) != EOF) {
|
||
|
|
adler = adler32(adler, buffer, length);
|
||
|
|
}
|
||
|
|
if (adler != original_adler) error();
|
||
|
|
*/
|
||
|
|
static inline uLong zlib_adler32(uLong adler,
|
||
|
|
const Byte *buf,
|
||
|
|
uInt len)
|
||
|
|
{
|
||
|
|
unsigned long s1 = adler & 0xffff;
|
||
|
|
unsigned long s2 = (adler >> 16) & 0xffff;
|
||
|
|
int k;
|
||
|
|
|
||
|
|
if (buf == NULL) return 1L;
|
||
|
|
|
||
|
|
while (len > 0) {
|
||
|
|
k = len < NMAX ? len : NMAX;
|
||
|
|
len -= k;
|
||
|
|
while (k >= 16) {
|
||
|
|
DO16(buf);
|
||
|
|
buf += 16;
|
||
|
|
k -= 16;
|
||
|
|
}
|
||
|
|
if (k != 0) do {
|
||
|
|
s1 += *buf++;
|
||
|
|
s2 += s1;
|
||
|
|
} while (--k);
|
||
|
|
s1 %= BASE;
|
||
|
|
s2 %= BASE;
|
||
|
|
}
|
||
|
|
return (s2 << 16) | s1;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* _Z_UTIL_H */
|