zlib/zutil.c

   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 struct internal_state      {int dummy;}; /* for buggy compilers */
  11
  12 #ifndef STDC
  13 extern void exit OF((int));
  14 #endif
  15
  16 const char *z_errmsg[10] = {
  17 "need dictionary",     /* Z_NEED_DICT       2  */
  18 "stream end",          /* Z_STREAM_END      1  */
  19 "",                    /* Z_OK              0  */
  20 "file error",          /* Z_ERRNO         (-1) */
  21 "stream error",        /* Z_STREAM_ERROR  (-2) */
  22 "data error",          /* Z_DATA_ERROR    (-3) */
  23 "insufficient memory", /* Z_MEM_ERROR     (-4) */
  24 "buffer error",        /* Z_BUF_ERROR     (-5) */
  25 "incompatible version",/* Z_VERSION_ERROR (-6) */
  26 ""};
  27
  28
  29 const char * ZEXPORT zlibVersion()
  30 {
  31     return ZLIB_VERSION;
  32 }
  33
  34 #ifdef DEBUG
  35
  36 #  ifndef verbose
  37 #    define verbose 0
  38 #  endif
  39 int z_verbose = verbose;
  40
  41 void z_error (m)
  42     char *m;
  43 {
  44     fprintf(stderr, "%s\n", m);
  45     exit(1);
  46 }
  47 #endif
  48
  49 /* exported to allow conversion of error code to string for compress() and
  50  * uncompress()
  51  */
  52 const char * ZEXPORT zError(err)
  53     int err;
  54 {
  55     return ERR_MSG(err);
  56 }
  57
  58
  59 #ifndef HAVE_MEMCPY
  60
  61 void zmemcpy(dest, source, len)
  62     Bytef* dest;
  63     const Bytef* source;
  64     uInt  len;
  65 {
  66     if (len == 0) return;
  67     do {
  68         *dest++ = *source++; /* ??? to be unrolled */
  69     } while (--len != 0);
  70 }
  71
  72 int zmemcmp(s1, s2, len)
  73     const Bytef* s1;
  74     const Bytef* s2;
  75     uInt  len;
  76 {
  77     uInt j;
  78
  79     for (j = 0; j < len; j++) {
  80         if (s1[j] != s2[j]) return 2*(s1[j] > s2[j])-1;
  81     }
  82     return 0;
  83 }
  84
  85 void zmemzero(dest, len)
  86     Bytef* dest;
  87     uInt  len;
  88 {
  89     if (len == 0) return;
  90     do {
  91         *dest++ = 0;  /* ??? to be unrolled */
  92     } while (--len != 0);
  93 }
  94 #endif
  95
  96 #ifdef __TURBOC__
  97 #if (defined( __BORLANDC__) || !defined(SMALL_MEDIUM)) && !defined(__32BIT__)
  98 /* Small and medium model in Turbo C are for now limited to near allocation
  99  * with reduced MAX_WBITS and MAX_MEM_LEVEL
 100  */
 101 #  define MY_ZCALLOC
 102
 103 /* Turbo C malloc() does not allow dynamic allocation of 64K bytes
 104  * and farmalloc(64K) returns a pointer with an offset of 8, so we
 105  * must fix the pointer. Warning: the pointer must be put back to its
 106  * original form in order to free it, use zcfree().
 107  */
 108
 109 #define MAX_PTR 10
 110 /* 10*64K = 640K */
 111
 112 local int next_ptr = 0;
 113
 114 typedef struct ptr_table_s {
 115     voidpf org_ptr;
 116     voidpf new_ptr;
 117 } ptr_table;
 118
 119 local ptr_table table[MAX_PTR];
 120 /* This table is used to remember the original form of pointers
 121  * to large buffers (64K). Such pointers are normalized with a zero offset.
 122  * Since MSDOS is not a preemptive multitasking OS, this table is not
 123  * protected from concurrent access. This hack doesn't work anyway on
 124  * a protected system like OS/2. Use Microsoft C instead.
 125  */
 126
 127 voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
 128 {
 129     voidpf buf = opaque; /* just to make some compilers happy */
 130     ulg bsize = (ulg)items*size;
 131
 132     /* If we allocate less than 65520 bytes, we assume that farmalloc
 133      * will return a usable pointer which doesn't have to be normalized.
 134      */
 135     if (bsize < 65520L) {
 136         buf = farmalloc(bsize);
 137         if (*(ush*)&buf != 0) return buf;
 138     } else {
 139         buf = farmalloc(bsize + 16L);
 140     }
 141     if (buf == NULL || next_ptr >= MAX_PTR) return NULL;
 142     table[next_ptr].org_ptr = buf;
 143
 144     /* Normalize the pointer to seg:0 */
 145     *((ush*)&buf+1) += ((ush)((uch*)buf-0) + 15) >> 4;
 146     *(ush*)&buf = 0;
 147     table[next_ptr++].new_ptr = buf;
 148     return buf;
 149 }
 150
 151 void  zcfree (voidpf opaque, voidpf ptr)
 152 {
 153     int n;
 154     if (*(ush*)&ptr != 0) { /* object < 64K */
 155         farfree(ptr);
 156         return;
 157     }
 158     /* Find the original pointer */
 159     for (n = 0; n < next_ptr; n++) {
 160         if (ptr != table[n].new_ptr) continue;
 161
 162         farfree(table[n].org_ptr);
 163         while (++n < next_ptr) {
 164             table[n-1] = table[n];
 165         }
 166         next_ptr--;
 167         return;
 168     }
 169     ptr = opaque; /* just to make some compilers happy */
 170     Assert(0, "zcfree: ptr not found");
 171 }
 172 #endif
 173 #endif /* __TURBOC__ */
 174
 175
 176 #if defined(M_I86) && !defined(__32BIT__)
 177 /* Microsoft C in 16-bit mode */
 178
 179 #  define MY_ZCALLOC
 180
 181 #if (!defined(_MSC_VER) || (_MSC_VER <= 600))
 182 #  define _halloc  halloc
 183 #  define _hfree   hfree
 184 #endif
 185
 186 voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
 187 {
 188     if (opaque) opaque = 0; /* to make compiler happy */
 189     return _halloc((long)items, size);
 190 }
 191
 192 void  zcfree (voidpf opaque, voidpf ptr)
 193 {
 194     if (opaque) opaque = 0; /* to make compiler happy */
 195     _hfree(ptr);
 196 }
 197
 198 #endif /* MSC */
 199
 200
 201 #ifndef MY_ZCALLOC /* Any system without a special alloc function */
 202
 203 voidpf zcalloc (opaque, items, size)
 204     voidpf opaque;
 205     unsigned items;
 206     unsigned size;
 207 {
 208     if (opaque) items += size - size; /* make compiler happy */
 209     return (voidpf)calloc(items, size);
 210 }
 211
 212 void  zcfree (opaque, ptr)
 213     voidpf opaque;
 214     voidpf ptr;
 215 {
 216     free(ptr);
 217     if (opaque) return; /* make compiler happy */
 218 }
 219
 220 #endif /* MY_ZCALLOC */