    /* zutil.c -- target dependent utility functions for the compression library
     * Copyright (C) 1995-2005, 2010, 2011, 2012 Jean-loup Gailly.
     * For conditions of distribution and use, see copyright notice in zlib.h
     */

    /* @(#) $Id$ */

    #include "zutil.h"
    #ifndef Z_SOLO
    #  include "gzguts.h"
    #endif

    #ifndef NO_DUMMY_DECL
    struct internal_state      {int dummy;}; /* for buggy compilers */
    #endif

    z_const char * const 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;
    }

    uLong ZEXPORT zlibCompileFlags()
    {
        uLong flags;

        flags = 0;
        switch ((int)(sizeof(uInt))) {
        case 2:     break;
        case 4:     flags += 1;     break;
        case 8:     flags += 2;     break;
        default:    flags += 3;
        }
        switch ((int)(sizeof(uLong))) {
        case 2:     break;
        case 4:     flags += 1 << 2;        break;
        case 8:     flags += 2 << 2;        break;
        default:    flags += 3 << 2;
        }
        switch ((int)(sizeof(voidpf))) {
        case 2:     break;
        case 4:     flags += 1 << 4;        break;
        case 8:     flags += 2 << 4;        break;
        default:    flags += 3 << 4;
        }
        switch ((int)(sizeof(z_off_t))) {
        case 2:     break;
        case 4:     flags += 1 << 6;        break;
        case 8:     flags += 2 << 6;        break;
        default:    flags += 3 << 6;
        }
    #ifdef DEBUG
        flags += 1 << 8;
    #endif
    #if defined(ASMV) || defined(ASMINF)
        flags += 1 << 9;
    #endif
    #ifdef ZLIB_WINAPI
        flags += 1 << 10;
    #endif
    #ifdef BUILDFIXED
        flags += 1 << 12;
    #endif
    #ifdef DYNAMIC_CRC_TABLE
        flags += 1 << 13;
    #endif
    #ifdef NO_GZCOMPRESS
        flags += 1L << 16;
    #endif
    #ifdef NO_GZIP
        flags += 1L << 17;
    #endif
    #ifdef PKZIP_BUG_WORKAROUND
        flags += 1L << 20;
    #endif
    #ifdef FASTEST
        flags += 1L << 21;
    #endif
    #if defined(STDC) || defined(Z_HAVE_STDARG_H)
    #  ifdef NO_vsnprintf
        flags += 1L << 25;
    #    ifdef HAS_vsprintf_void
        flags += 1L << 26;
    #    endif
    #  else
    #    ifdef HAS_vsnprintf_void
        flags += 1L << 26;
    #    endif
    #  endif
    #else
        flags += 1L << 24;
    #  ifdef NO_snprintf
        flags += 1L << 25;
    #    ifdef HAS_sprintf_void
        flags += 1L << 26;
    #    endif
    #  else
    #    ifdef HAS_snprintf_void
        flags += 1L << 26;
    #    endif
    #  endif
    #endif
        return flags;
    }

    #ifdef DEBUG

    #  ifndef verbose
    #    define verbose 0
    #  endif
    int ZLIB_INTERNAL z_verbose = verbose;

    void ZLIB_INTERNAL z_error (m)
        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(err)
        int err;
    {
        return ERR_MSG(err);
    }

    #if defined(_WIN32_WCE)
        /* The Microsoft C Run-Time Library for Windows CE doesn't have
         * errno.  We define it as a global variable to simplify porting.
         * Its value is always 0 and should not be used.
         */
        int errno = 0;
    #endif

    #ifndef HAVE_MEMCPY

    void ZLIB_INTERNAL 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 ZLIB_INTERNAL 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 ZLIB_INTERNAL zmemzero(dest, len)
        Bytef* dest;
        uInt  len;
    {
        if (len == 0) return;
        do {
            *dest++ = 0;  /* ??? to be unrolled */
        } while (--len != 0);
    }
    #endif

    #ifndef Z_SOLO

    #ifdef SYS16BIT

    #ifdef __TURBOC__
    /* Turbo C in 16-bit mode */

    #  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 ZLIB_INTERNAL 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 ZLIB_INTERNAL 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 /* __TURBOC__ */

    #ifdef M_I86
    /* Microsoft C in 16-bit mode */

    #  define MY_ZCALLOC

    #if (!defined(_MSC_VER) || (_MSC_VER <= 600))
    #  define _halloc  halloc
    #  define _hfree   hfree
    #endif

    voidpf ZLIB_INTERNAL zcalloc (voidpf opaque, uInt items, uInt size)
    {
        if (opaque) opaque = 0; /* to make compiler happy */
        return _halloc((long)items, size);
    }

    void ZLIB_INTERNAL zcfree (voidpf opaque, voidpf ptr)
    {
        if (opaque) opaque = 0; /* to make compiler happy */
        _hfree(ptr);
    }

    #endif /* M_I86 */

    #endif /* SYS16BIT */

    #ifndef MY_ZCALLOC /* Any system without a special alloc function */

    #ifndef STDC
    extern voidp  malloc OF((uInt size));
    extern voidp  calloc OF((uInt items, uInt size));
    extern void   free   OF((voidpf ptr));
    #endif

    voidpf ZLIB_INTERNAL zcalloc (opaque, items, size)
        voidpf opaque;
        unsigned items;
        unsigned size;
    {
        if (opaque) items += size - size; /* make compiler happy */
        return sizeof(uInt) > 2 ? (voidpf)malloc(items * size) :
                                  (voidpf)calloc(items, size);
    }

    void ZLIB_INTERNAL zcfree (opaque, ptr)
        voidpf opaque;
        voidpf ptr;
    {
        free(ptr);
        if (opaque) return; /* make compiler happy */
    }

    #endif /* MY_ZCALLOC */

    #endif /* !Z_SOLO */