text: /* 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: zutil.c,v 1.3 2006/04/29 07:31:16 wl Exp $ */
  
  #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
  
  #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  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 */
  
  
  #ifdef DEBUG
  int z_verbose = 0;
  void z_error(char *m) {
  }
  #endif
  
  