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

 * Copyright (C) 1995-2017 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

z_const char * const z_errmsg[10] = {

    (z_const char *)"need dictionary",     /* Z_NEED_DICT       2  */

    (z_const char *)"stream end",          /* Z_STREAM_END      1  */

    (z_const char *)"",                    /* Z_OK              0  */

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

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

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

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

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

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

    (z_const char *)""

};

const char * ZEXPORT zlibVersion(void) {

    return ZLIB_VERSION;

}

uLong ZEXPORT zlibCompileFlags(void) {

    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 ZLIB_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

#       ifdef ZLIB_INSECURE

            flags += 1L << 25;

#       else

            flags += 1L << 27;

#       endif

#       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

#       ifdef ZLIB_INSECURE

            flags += 1L << 25;

#       else

            flags += 1L << 27;

#       endif

#       ifdef HAS_sprintf_void

            flags += 1L << 26;

#       endif

#   else

#       ifdef HAS_snprintf_void

            flags += 1L << 26;

#       endif

#   endif

#endif

    return flags;

}

#ifdef ZLIB_DEBUG

#include <stdlib.h>

#  ifndef verbose

#    define verbose 0

#  endif

int ZLIB_INTERNAL z_verbose = verbose;

void ZLIB_INTERNAL 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);

}

#if defined(_WIN32_WCE) && _WIN32_WCE < 0x800

    /* The older 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(Bytef* dest, const Bytef* source, uInt len) {

    if (len == 0) return;

    do {

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

    } while (--len != 0);

}

int ZLIB_INTERNAL 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 ZLIB_INTERNAL zmemzero(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;

    ulg bsize = (ulg)items*size;

    (void)opaque;

    /* 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;

    (void)opaque;

    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;

    }

    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) {

    (void)opaque;

    return _halloc((long)items, size);

}

void ZLIB_INTERNAL zcfree(voidpf opaque, voidpf ptr) {

    (void)opaque;

    _hfree(ptr);

}

#endif /* M_I86 */

#endif /* SYS16BIT */

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

#ifndef STDC

extern voidp malloc(uInt size);

extern voidp calloc(uInt items, uInt size);

extern void free(voidpf ptr);

#endif

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

    (void)opaque;

    return sizeof(uInt) > 2 ? (voidpf)malloc(items * size) :

                              (voidpf)calloc(items, size);

}

void ZLIB_INTERNAL zcfree(voidpf opaque, voidpf ptr) {

    (void)opaque;

    free(ptr);

}

#endif /* MY_ZCALLOC */

#endif /* !Z_SOLO */

#if defined(BUILDFIXED) || defined(DYNAMIC_CRC_TABLE)

/*

  Define a z_once() function depending on the availability of atomics.

 */

/* Check for the availability of atomics. */

#if defined(__STDC__) && __STDC_VERSION__ >= 201112L && \

    !defined(__STDC_NO_ATOMICS__)

#include <stdatomic.h>

/*

  Run the provided init() function exactly once, even if multiple threads

  invoke once() at the same time. The state must be a once_t initialized with

  Z_ONCE_INIT.

 */

void z_once(z_once_t *state, void (*init)(void)) {

    if (!atomic_load(&state->done)) {

        if (atomic_flag_test_and_set(&state->begun))

            while (!atomic_load(&state->done))

                ;

        else {

            init();

            atomic_store(&state->done, 1);

        }

    }

}

#else   /* no atomics */

#warning zlib not thread-safe

/* Test and set. Alas, not atomic, but tries to limit the period of

   vulnerability. */

local int test_and_set(int volatile *flag) {

    int was;

    was = *flag;

    *flag = 1;

    return was;

}

/* Run the provided init() function once. This is not thread-safe. */

void z_once(z_once_t *state, void (*init)(void)) {

    if (!state->done) {

        if (test_and_set(&state->begun))

            while (!state->done)

                ;

        else {

            init();

            state->done = 1;

        }

    }

}

#endif

#endif