ref: cb4a943bc4d24d48eeb5d1515c5acd880c4a82ab
dir: /src/gzip/zutil.c/
/* zutil.c -- target dependent utility functions for the compression library
* Copyright (C) 1995-2002 Jean-loup Gailly.
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/* @(#) $Id$ */
#include "zutil.h"
#ifndef STDC
extern void exit OF((int));
#endif
#ifndef HAVE_MEMCPY
void zmemcpy(dest, source, len)
Bytef* dest;
const Bytef* source;
uInt len;
{
if (len == 0) return;
do {
*dest++ = *source++; /* ??? to be unrolled */
} while (--len != 0);
}
int zmemcmp(s1, s2, len)
const Bytef* s1;
const Bytef* s2;
uInt len;
{
uInt j;
for (j = 0; j < len; j++) {
if (s1[j] != s2[j]) return 2*(s1[j] > s2[j])-1;
}
return 0;
}
void zmemzero(dest, len)
Bytef* dest;
uInt len;
{
if (len == 0) return;
do {
*dest++ = 0; /* ??? to be unrolled */
} while (--len != 0);
}
#endif
#if defined( MSDOS ) && defined( __TURBOC__ ) && !defined( MY_ZCALLOC )
#if (defined( __BORLANDC__) || !defined(SMALL_MEDIUM)) && !defined(__32BIT__)
/* Small and medium model in Turbo C are for now limited to near allocation
* with reduced MAX_WBITS and MAX_MEM_LEVEL
*/
# define MY_ZCALLOC
/* Turbo C malloc() does not allow dynamic allocation of 64K bytes
* and farmalloc(64K) returns a pointer with an offset of 8, so we
* must fix the pointer. Warning: the pointer must be put back to its
* original form in order to free it, use zcfree().
*/
#define MAX_PTR 10
/* 10*64K = 640K */
local int next_ptr = 0;
typedef struct ptr_table_s {
voidpf org_ptr;
voidpf new_ptr;
} ptr_table;
local ptr_table table[MAX_PTR];
/* This table is used to remember the original form of pointers
* to large buffers (64K). Such pointers are normalized with a zero offset.
* Since MSDOS is not a preemptive multitasking OS, this table is not
* protected from concurrent access. This hack doesn't work anyway on
* a protected system like OS/2. Use Microsoft C instead.
*/
voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
{
voidpf buf = opaque; /* just to make some compilers happy */
ulg bsize = (ulg)items*size;
/* If we allocate less than 65520 bytes, we assume that farmalloc
* will return a usable pointer which doesn't have to be normalized.
*/
if (bsize < 65520L) {
buf = farmalloc(bsize);
if (*(ush*)&buf != 0) return buf;
} else {
buf = farmalloc(bsize + 16L);
}
if (buf == NULL || next_ptr >= MAX_PTR) return NULL;
table[next_ptr].org_ptr = buf;
/* Normalize the pointer to seg:0 */
*((ush*)&buf+1) += ((ush)((uch*)buf-0) + 15) >> 4;
*(ush*)&buf = 0;
table[next_ptr++].new_ptr = buf;
return buf;
}
void zcfree (voidpf opaque, voidpf ptr)
{
int n;
if (*(ush*)&ptr != 0) { /* object < 64K */
farfree(ptr);
return;
}
/* Find the original pointer */
for (n = 0; n < next_ptr; n++) {
if (ptr != table[n].new_ptr) continue;
farfree(table[n].org_ptr);
while (++n < next_ptr) {
table[n-1] = table[n];
}
next_ptr--;
return;
}
ptr = opaque; /* just to make some compilers happy */
Assert(0, "zcfree: ptr not found");
}
#endif
#endif /* MSDOS && __TURBOC__ */
#if defined(M_I86) && !defined(__32BIT__) && !defined( MY_ZCALLOC )
/* Microsoft C in 16-bit mode */
# define MY_ZCALLOC
#if (!defined(_MSC_VER) || (_MSC_VER <= 600))
# define _halloc halloc
# define _hfree hfree
#endif
voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
{
if (opaque) opaque = 0; /* to make compiler happy */
return _halloc((long)items, size);
}
void zcfree (voidpf opaque, voidpf ptr)
{
if (opaque) opaque = 0; /* to make compiler happy */
_hfree(ptr);
}
#endif /* MSC */
#ifndef MY_ZCALLOC /* Any system without a special alloc function */
#ifndef STDC
extern voidp ft_scalloc OF((uInt items, uInt size));
extern void ft_sfree OF((voidpf ptr));
#endif
voidpf zcalloc (opaque, items, size)
voidpf opaque;
unsigned items;
unsigned size;
{
if (opaque) items += size - size; /* make compiler happy */
return (voidpf)ft_scalloc(items, size);
}
void zcfree (opaque, ptr)
voidpf opaque;
voidpf ptr;
{
ft_sfree(ptr);
if (opaque) return; /* make compiler happy */
}
#endif /* MY_ZCALLOC */