/* zutil.c -- target dependent utility functions for the compression library

  * Copyright (C) 1995-1998 Jean-loup Gailly.

  * For conditions of distribution and use, see copyright notice in zlib.h 

  */

 /* @(#) $Id$ */

 #include "zutil.h"

 struct internal_state      {int dummy;}; /* for buggy compilers */

 #ifndef STDC

 extern void exit OF((int));

 #endif

 const char *z_errmsg[10] = {

 "need dictionary",     /* Z_NEED_DICT       2  */

 "stream end",          /* Z_STREAM_END      1  */

 "",                    /* Z_OK              0  */

 "file error",          /* Z_ERRNO         (-1) */

 "stream error",        /* Z_STREAM_ERROR  (-2) */

 "data error",          /* Z_DATA_ERROR    (-3) */

 "insufficient memory", /* Z_MEM_ERROR     (-4) */

 "buffer error",        /* Z_BUF_ERROR     (-5) */

 "incompatible version",/* Z_VERSION_ERROR (-6) */

 ""};

 const char * ZEXPORT zlibVersion()

 {

     return ZLIB_VERSION;

 }

 #ifdef DEBUG

 #  ifndef verbose

 #    define verbose 0

 #  endif

 int z_verbose = verbose;

 void z_error (char *m)

 {

     fprintf(stderr, "%s\n", m);

     exit(1);

 }

 #endif

 /* exported to allow conversion of error code to string for compress() and

  * uncompress()

  */

 const char * ZEXPORT zError(int err)

 {

     return ERR_MSG(err);

 }

 #ifndef HAVE_MEMCPY

 void zmemcpy(Bytef* dest, const Bytef* source, uInt len)

 {

     if (len == 0) return;

     do {

         *dest++ = *source++; /* ??? to be unrolled */

     } while (--len != 0);

 }

 int zmemcmp(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(Bytef* dest, uInt len)

 {

     if (len == 0) return;

     do {

         *dest++ = 0;  /* ??? to be unrolled */

     } while (--len != 0);

 }

 #endif

 #ifdef __TURBOC__

 #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 /* __TURBOC__ */

 #if defined(M_I86) && !defined(__32BIT__)

 /* 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  calloc OF((uInt items, uInt size));

 extern void   free   OF((voidpf ptr));

 #endif

 voidpf zcalloc (voidpf opaque, unsigned items, unsigned size)

 {

     if (opaque) items += size - size; /* make compiler happy */

     return (voidpf)calloc(items, size);

 }

 void  zcfree (voidpf opaque,voidpf ptr)

 {

     free(ptr);

     if (opaque) return; /* make compiler happy */

 }

 #endif /* MY_ZCALLOC */