linux/lib/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: zutil.c,v 1.1 2004/03/15 20:35:26 as Exp $ */
   7
   8 #include <zlib/zutil.h>
   9
  10 #define MY_ZCALLOC
  11
  12 struct internal_state      {int dummy;}; /* for buggy compilers */
  13
  14 #ifndef STDC
  15 extern void exit OF((int));
  16 #endif
  17
  18 const char *z_errmsg[10] = {
  19 "need dictionary",     /* Z_NEED_DICT       2  */
  20 "stream end",          /* Z_STREAM_END      1  */
  21 "",                    /* Z_OK              0  */
  22 "file error",          /* Z_ERRNO         (-1) */
  23 "stream error",        /* Z_STREAM_ERROR  (-2) */
  24 "data error",          /* Z_DATA_ERROR    (-3) */
  25 "insufficient memory", /* Z_MEM_ERROR     (-4) */
  26 "buffer error",        /* Z_BUF_ERROR     (-5) */
  27 "incompatible version",/* Z_VERSION_ERROR (-6) */
  28 ""};
  29
  30
  31 const char * ZEXPORT zlibVersion()
  32 {
  33     return ZLIB_VERSION;
  34 }
  35
  36 #ifdef DEBUG
  37
  38 #  ifndef verbose
  39 #    define verbose 0
  40 #  endif
  41 int z_verbose = verbose;
  42
  43 void z_error (m)
  44     char *m;
  45 {
  46     fprintf(stderr, "%s\n", m);
  47     exit(1);
  48 }
  49 #endif
  50
  51 /* exported to allow conversion of error code to string for compress() and
  52  * uncompress()
  53  */
  54 const char * ZEXPORT zError(err)
  55     int err;
  56 {
  57     return ERR_MSG(err);
  58 }
  59
  60
  61 #ifndef HAVE_MEMCPY
  62
  63 void zmemcpy(dest, source, len)
  64     Bytef* dest;
  65     const Bytef* source;
  66     uInt  len;
  67 {
  68     if (len == 0) return;
  69     do {
  70         *dest++ = *source++; /* ??? to be unrolled */
  71     } while (--len != 0);
  72 }
  73
  74 int zmemcmp(s1, s2, len)
  75     const Bytef* s1;
  76     const Bytef* s2;
  77     uInt  len;
  78 {
  79     uInt j;
  80
  81     for (j = 0; j < len; j++) {
  82         if (s1[j] != s2[j]) return 2*(s1[j] > s2[j])-1;
  83     }
  84     return 0;
  85 }
  86
  87 void zmemzero(dest, len)
  88     Bytef* dest;
  89     uInt  len;
  90 {
  91     if (len == 0) return;
  92     do {
  93         *dest++ = 0;  /* ??? to be unrolled */
  94     } while (--len != 0);
  95 }
  96 #endif
  97
  98 #ifdef __TURBOC__
  99 #if (defined( __BORLANDC__) || !defined(SMALL_MEDIUM)) && !defined(__32BIT__)
 100 /* Small and medium model in Turbo C are for now limited to near allocation
 101  * with reduced MAX_WBITS and MAX_MEM_LEVEL
 102  */
 103 #  define MY_ZCALLOC
 104
 105 /* Turbo C malloc() does not allow dynamic allocation of 64K bytes
 106  * and farmalloc(64K) returns a pointer with an offset of 8, so we
 107  * must fix the pointer. Warning: the pointer must be put back to its
 108  * original form in order to free it, use zcfree().
 109  */
 110
 111 #define MAX_PTR 10
 112 /* 10*64K = 640K */
 113
 114 local int next_ptr = 0;
 115
 116 typedef struct ptr_table_s {
 117     voidpf org_ptr;
 118     voidpf new_ptr;
 119 } ptr_table;
 120
 121 local ptr_table table[MAX_PTR];
 122 /* This table is used to remember the original form of pointers
 123  * to large buffers (64K). Such pointers are normalized with a zero offset.
 124  * Since MSDOS is not a preemptive multitasking OS, this table is not
 125  * protected from concurrent access. This hack doesn't work anyway on
 126  * a protected system like OS/2. Use Microsoft C instead.
 127  */
 128
 129 voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
 130 {
 131     voidpf buf = opaque; /* just to make some compilers happy */
 132     ulg bsize = (ulg)items*size;
 133
 134     /* If we allocate less than 65520 bytes, we assume that farmalloc
 135      * will return a usable pointer which doesn't have to be normalized.
 136      */
 137     if (bsize < 65520L) {
 138         buf = farmalloc(bsize);
 139         if (*(ush*)&buf != 0) return buf;
 140     } else {
 141         buf = farmalloc(bsize + 16L);
 142     }
 143     if (buf == NULL || next_ptr >= MAX_PTR) return NULL;
 144     table[next_ptr].org_ptr = buf;
 145
 146     /* Normalize the pointer to seg:0 */
 147     *((ush*)&buf+1) += ((ush)((uch*)buf-0) + 15) >> 4;
 148     *(ush*)&buf = 0;
 149     table[next_ptr++].new_ptr = buf;
 150     return buf;
 151 }
 152
 153 void  zcfree (voidpf opaque, voidpf ptr)
 154 {
 155     int n;
 156     if (*(ush*)&ptr != 0) { /* object < 64K */
 157         farfree(ptr);
 158         return;
 159     }
 160     /* Find the original pointer */
 161     for (n = 0; n < next_ptr; n++) {
 162         if (ptr != table[n].new_ptr) continue;
 163
 164         farfree(table[n].org_ptr);
 165         while (++n < next_ptr) {
 166             table[n-1] = table[n];
 167         }
 168         next_ptr--;
 169         return;
 170     }
 171     ptr = opaque; /* just to make some compilers happy */
 172     Assert(0, "zcfree: ptr not found");
 173 }
 174 #endif
 175 #endif /* __TURBOC__ */
 176
 177
 178 #if defined(M_I86) && !defined(__32BIT__)
 179 /* Microsoft C in 16-bit mode */
 180
 181 #  define MY_ZCALLOC
 182
 183 #if (!defined(_MSC_VER) || (_MSC_VER <= 600))
 184 #  define _halloc  halloc
 185 #  define _hfree   hfree
 186 #endif
 187
 188 voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)
 189 {
 190     if (opaque) opaque = 0; /* to make compiler happy */
 191     return _halloc((long)items, size);
 192 }
 193
 194 void  zcfree (voidpf opaque, voidpf ptr)
 195 {
 196     if (opaque) opaque = 0; /* to make compiler happy */
 197     _hfree(ptr);
 198 }
 199
 200 #endif /* MSC */
 201
 202
 203 #ifndef MY_ZCALLOC /* Any system without a special alloc function */
 204
 205 #ifndef STDC
 206 extern voidp  calloc OF((uInt items, uInt size));
 207 extern void   free   OF((voidpf ptr));
 208 #endif
 209
 210 voidpf zcalloc (opaque, items, size)
 211     voidpf opaque;
 212     unsigned items;
 213     unsigned size;
 214 {
 215     if (opaque) items += size - size; /* make compiler happy */
 216     return (voidpf)calloc(items, size);
 217 }
 218
 219 void  zcfree (opaque, ptr)
 220     voidpf opaque;
 221     voidpf ptr;
 222 {
 223     free(ptr);
 224     if (opaque) return; /* make compiler happy */
 225 }
 226
 227 #endif /* MY_ZCALLOC */