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1 /* zutil.c -- target dependent utility functions for the compression library
2  * Copyright (C) 1995-2002 Jean-loup Gailly.
3  * For conditions of distribution and use, see copyright notice in zlib.h
4  */
5 
6 /* @(#) $Id$ */
7 
8 #include "zutil.h"
9 
10 #ifndef STDC
11 extern void exit OF((int));
12 #endif
13 
14 
15 #ifndef HAVE_MEMCPY
16 
zmemcpy(dest,source,len)17 void zmemcpy(dest, source, len)
18     Bytef* dest;
19     const Bytef* source;
20     uInt  len;
21 {
22     if (len == 0) return;
23     do {
24         *dest++ = *source++; /* ??? to be unrolled */
25     } while (--len != 0);
26 }
27 
zmemcmp(s1,s2,len)28 int zmemcmp(s1, s2, len)
29     const Bytef* s1;
30     const Bytef* s2;
31     uInt  len;
32 {
33     uInt j;
34 
35     for (j = 0; j < len; j++) {
36         if (s1[j] != s2[j]) return 2*(s1[j] > s2[j])-1;
37     }
38     return 0;
39 }
40 
zmemzero(dest,len)41 void zmemzero(dest, len)
42     Bytef* dest;
43     uInt  len;
44 {
45     if (len == 0) return;
46     do {
47         *dest++ = 0;  /* ??? to be unrolled */
48     } while (--len != 0);
49 }
50 #endif
51 
52 #if defined( MSDOS ) && defined( __TURBOC__ ) && !defined( MY_ZCALLOC )
53 #if (defined( __BORLANDC__) || !defined(SMALL_MEDIUM)) && !defined(__32BIT__)
54 /* Small and medium model in Turbo C are for now limited to near allocation
55  * with reduced MAX_WBITS and MAX_MEM_LEVEL
56  */
57 #  define MY_ZCALLOC
58 
59 /* Turbo C malloc() does not allow dynamic allocation of 64K bytes
60  * and farmalloc(64K) returns a pointer with an offset of 8, so we
61  * must fix the pointer. Warning: the pointer must be put back to its
62  * original form in order to free it, use zcfree().
63  */
64 
65 #define MAX_PTR 10
66 /* 10*64K = 640K */
67 
68 local int next_ptr = 0;
69 
70 typedef struct ptr_table_s {
71     voidpf org_ptr;
72     voidpf new_ptr;
73 } ptr_table;
74 
75 local ptr_table table[MAX_PTR];
76 /* This table is used to remember the original form of pointers
77  * to large buffers (64K). Such pointers are normalized with a zero offset.
78  * Since MSDOS is not a preemptive multitasking OS, this table is not
79  * protected from concurrent access. This hack doesn't work anyway on
80  * a protected system like OS/2. Use Microsoft C instead.
81  */
82 
zcalloc(voidpf opaque,unsigned items,unsigned size)83 voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
84 {
85     voidpf buf = opaque; /* just to make some compilers happy */
86     ulg bsize = (ulg)items*size;
87 
88     /* If we allocate less than 65520 bytes, we assume that farmalloc
89      * will return a usable pointer which doesn't have to be normalized.
90      */
91     if (bsize < 65520L) {
92         buf = farmalloc(bsize);
93         if (*(ush*)&buf != 0) return buf;
94     } else {
95         buf = farmalloc(bsize + 16L);
96     }
97     if (buf == NULL || next_ptr >= MAX_PTR) return NULL;
98     table[next_ptr].org_ptr = buf;
99 
100     /* Normalize the pointer to seg:0 */
101     *((ush*)&buf+1) += ((ush)((uch*)buf-0) + 15) >> 4;
102     *(ush*)&buf = 0;
103     table[next_ptr++].new_ptr = buf;
104     return buf;
105 }
106 
zcfree(voidpf opaque,voidpf ptr)107 void  zcfree (voidpf opaque, voidpf ptr)
108 {
109     int n;
110     if (*(ush*)&ptr != 0) { /* object < 64K */
111         farfree(ptr);
112         return;
113     }
114     /* Find the original pointer */
115     for (n = 0; n < next_ptr; n++) {
116         if (ptr != table[n].new_ptr) continue;
117 
118         farfree(table[n].org_ptr);
119         while (++n < next_ptr) {
120             table[n-1] = table[n];
121         }
122         next_ptr--;
123         return;
124     }
125     ptr = opaque; /* just to make some compilers happy */
126     Assert(0, "zcfree: ptr not found");
127 }
128 #endif
129 #endif /* MSDOS && __TURBOC__ */
130 
131 
132 #if defined(M_I86) && !defined(__32BIT__) && !defined( MY_ZCALLOC )
133 /* Microsoft C in 16-bit mode */
134 
135 #  define MY_ZCALLOC
136 
137 #if (!defined(_MSC_VER) || (_MSC_VER <= 600))
138 #  define _halloc  halloc
139 #  define _hfree   hfree
140 #endif
141 
zcalloc(voidpf opaque,unsigned items,unsigned size)142 voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
143 {
144     if (opaque) opaque = 0; /* to make compiler happy */
145     return _halloc((long)items, size);
146 }
147 
zcfree(voidpf opaque,voidpf ptr)148 void  zcfree (voidpf opaque, voidpf ptr)
149 {
150     if (opaque) opaque = 0; /* to make compiler happy */
151     _hfree(ptr);
152 }
153 
154 #endif /* MSC */
155 
156 
157 #ifndef MY_ZCALLOC /* Any system without a special alloc function */
158 
159 #ifndef STDC
160 extern voidp  ft_scalloc OF((uInt items, uInt size));
161 extern void   ft_sfree   OF((voidpf ptr));
162 #endif
163 
zcalloc(opaque,items,size)164 voidpf zcalloc (opaque, items, size)
165     voidpf opaque;
166     unsigned items;
167     unsigned size;
168 {
169     if (opaque) items += size - size; /* make compiler happy */
170     return (voidpf)ft_scalloc(items, size);
171 }
172 
zcfree(opaque,ptr)173 void  zcfree (opaque, ptr)
174     voidpf opaque;
175     voidpf ptr;
176 {
177     ft_sfree(ptr);
178     if (opaque) return; /* make compiler happy */
179 }
180 
181 #endif /* MY_ZCALLOC */
182