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zlib/zutil.h
Mark Adler c267ef7306 Use atomics to build inflate fixed tables once. 
This moves the once code from crc32.c to zutil.c, and uses it also
for building the inflate fixed tables when BUILDFIXED is defined.
The fixed tables are now housed in inftrees.c, shared by inflate.c
and infback.c. The once() function is now external, and so is
renamed to z_once() to avoid name collisions.

If either BUILDFIXED or DYNAMIC_CRC_TABLE is defined, and atomics
are not available, then a warning is issued noting that zlib is not
thread-safe.
2026-01-05 15:03:04 -06:00

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/* zutil.h -- internal interface and configuration of the compression library
* Copyright (C) 1995-2024 Jean-loup Gailly, Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/* WARNING: this file should *not* be used by applications. It is
part of the implementation of the compression library and is
subject to change. Applications should only use zlib.h.
*/
/* @(#) $Id$ */
#ifndef ZUTIL_H
#define ZUTIL_H
#ifdef HAVE_HIDDEN
# define ZLIB_INTERNAL __attribute__((visibility ("hidden")))
#else
# define ZLIB_INTERNAL
#endif
#include "zlib.h"
#if defined(STDC) && !defined(Z_SOLO)
# if !(defined(_WIN32_WCE) && defined(_MSC_VER))
# include <stddef.h>
# endif
# include <string.h>
# include <stdlib.h>
#endif
#ifndef local
# define local static
#endif
/* since "static" is used to mean two completely different things in C, we
define "local" for the non-static meaning of "static", for readability
(compile with -Dlocal if your debugger can't find static symbols) */
typedef unsigned char uch;
typedef uch FAR uchf;
typedef unsigned short ush;
typedef ush FAR ushf;
typedef unsigned long ulg;
#if !defined(Z_U8) && !defined(Z_SOLO) && defined(STDC)
# include <limits.h>
# if (ULONG_MAX == 0xffffffffffffffff)
# define Z_U8 unsigned long
# elif (ULLONG_MAX == 0xffffffffffffffff)
# define Z_U8 unsigned long long
# elif (ULONG_LONG_MAX == 0xffffffffffffffff)
# define Z_U8 unsigned long long
# elif (UINT_MAX == 0xffffffffffffffff)
# define Z_U8 unsigned
# endif
#endif
extern z_const char * const z_errmsg[10]; /* indexed by 2-zlib_error */
/* (size given to avoid silly warnings with Visual C++) */
#define ERR_MSG(err) z_errmsg[(err) < -6 || (err) > 2 ? 9 : 2 - (err)]
#define ERR_RETURN(strm,err) \
return (strm->msg = ERR_MSG(err), (err))
/* To be used only when the state is known to be valid */
/* common constants */
#if MAX_WBITS < 9 || MAX_WBITS > 15
# error MAX_WBITS must be in 9..15
#endif
#ifndef DEF_WBITS
# define DEF_WBITS MAX_WBITS
#endif
/* default windowBits for decompression. MAX_WBITS is for compression only */
#if MAX_MEM_LEVEL >= 8
# define DEF_MEM_LEVEL 8
#else
# define DEF_MEM_LEVEL MAX_MEM_LEVEL
#endif
/* default memLevel */
#define STORED_BLOCK 0
#define STATIC_TREES 1
#define DYN_TREES 2
/* The three kinds of block type */
#define MIN_MATCH 3
#define MAX_MATCH 258
/* The minimum and maximum match lengths */
#define PRESET_DICT 0x20 /* preset dictionary flag in zlib header */
/* target dependencies */
#if defined(MSDOS) || (defined(WINDOWS) && !defined(WIN32))
# define OS_CODE 0x00
# ifndef Z_SOLO
# if defined(__TURBOC__) || defined(__BORLANDC__)
# if (__STDC__ == 1) && (defined(__LARGE__) || defined(__COMPACT__))
/* Allow compilation with ANSI keywords only enabled */
void _Cdecl farfree( void *block );
void *_Cdecl farmalloc( unsigned long nbytes );
# else
# include <alloc.h>
# endif
# else /* MSC or DJGPP */
# include <malloc.h>
# endif
# endif
#endif
#ifdef AMIGA
# define OS_CODE 1
#endif
#if defined(VAXC) || defined(VMS)
# define OS_CODE 2
# define F_OPEN(name, mode) \
fopen((name), (mode), "mbc=60", "ctx=stm", "rfm=fix", "mrs=512")
#endif
#ifdef __370__
# if __TARGET_LIB__ < 0x20000000
# define OS_CODE 4
# elif __TARGET_LIB__ < 0x40000000
# define OS_CODE 11
# else
# define OS_CODE 8
# endif
#endif
#if defined(ATARI) || defined(atarist)
# define OS_CODE 5
#endif
#ifdef OS2
# define OS_CODE 6
# if defined(M_I86) && !defined(Z_SOLO)
# include <malloc.h>
# endif
#endif
#if defined(MACOS)
# define OS_CODE 7
#endif
#if defined(__acorn) || defined(__riscos)
# define OS_CODE 13
#endif
#if defined(WIN32) && !defined(__CYGWIN__)
# define OS_CODE 10
#endif
#ifdef _BEOS_
# define OS_CODE 16
#endif
#ifdef __TOS_OS400__
# define OS_CODE 18
#endif
#ifdef __APPLE__
# define OS_CODE 19
#endif
#if defined(__BORLANDC__) && !defined(MSDOS)
#pragma warn -8004
#pragma warn -8008
#pragma warn -8066
#endif
/* provide prototypes for these when building zlib without LFS */
#ifndef Z_LARGE64
ZEXTERN uLong ZEXPORT adler32_combine64(uLong, uLong, z_off64_t);
ZEXTERN uLong ZEXPORT crc32_combine64(uLong, uLong, z_off64_t);
ZEXTERN uLong ZEXPORT crc32_combine_gen64(z_off64_t);
#endif
/* common defaults */
#ifndef OS_CODE
# define OS_CODE 3 /* assume Unix */
#endif
#ifndef F_OPEN
# define F_OPEN(name, mode) fopen((name), (mode))
#endif
/* functions */
#if defined(pyr) || defined(Z_SOLO)
# define NO_MEMCPY
#endif
#if defined(SMALL_MEDIUM) && !defined(_MSC_VER) && !defined(__SC__)
/* Use our own functions for small and medium model with MSC <= 5.0.
* You may have to use the same strategy for Borland C (untested).
* The __SC__ check is for Symantec.
*/
# define NO_MEMCPY
#endif
#if defined(STDC) && !defined(HAVE_MEMCPY) && !defined(NO_MEMCPY)
# define HAVE_MEMCPY
#endif
#ifdef HAVE_MEMCPY
# ifdef SMALL_MEDIUM /* MSDOS small or medium model */
# define zmemcpy _fmemcpy
# define zmemcmp _fmemcmp
# define zmemzero(dest, len) _fmemset(dest, 0, len)
# else
# define zmemcpy memcpy
# define zmemcmp memcmp
# define zmemzero(dest, len) memset(dest, 0, len)
# endif
#else
void ZLIB_INTERNAL zmemcpy(Bytef* dest, const Bytef* source, uInt len);
int ZLIB_INTERNAL zmemcmp(const Bytef* s1, const Bytef* s2, uInt len);
void ZLIB_INTERNAL zmemzero(Bytef* dest, uInt len);
#endif
/* Diagnostic functions */
#ifdef ZLIB_DEBUG
# include <stdio.h>
extern int ZLIB_INTERNAL z_verbose;
extern void ZLIB_INTERNAL z_error(char *m);
# define Assert(cond,msg) {if(!(cond)) z_error(msg);}
# define Trace(x) {if (z_verbose>=0) fprintf x ;}
# define Tracev(x) {if (z_verbose>0) fprintf x ;}
# define Tracevv(x) {if (z_verbose>1) fprintf x ;}
# define Tracec(c,x) {if (z_verbose>0 && (c)) fprintf x ;}
# define Tracecv(c,x) {if (z_verbose>1 && (c)) fprintf x ;}
#else
# define Assert(cond,msg)
# define Trace(x)
# define Tracev(x)
# define Tracevv(x)
# define Tracec(c,x)
# define Tracecv(c,x)
#endif
#ifndef Z_SOLO
voidpf ZLIB_INTERNAL zcalloc(voidpf opaque, unsigned items,
unsigned size);
void ZLIB_INTERNAL zcfree(voidpf opaque, voidpf ptr);
#endif
#define ZALLOC(strm, items, size) \
(*((strm)->zalloc))((strm)->opaque, (items), (size))
#define ZFREE(strm, addr) (*((strm)->zfree))((strm)->opaque, (voidpf)(addr))
#define TRY_FREE(s, p) {if (p) ZFREE(s, p);}
/* Reverse the bytes in a 32-bit value */
#define ZSWAP32(q) ((((q) >> 24) & 0xff) + (((q) >> 8) & 0xff00) + \
(((q) & 0xff00) << 8) + (((q) & 0xff) << 24))
#ifdef MAKEFIXED
# ifndef BUILDFIXED
# define BUILDFIXED
# endif
#endif
#if defined(BUILDFIXED) || defined(DYNAMIC_CRC_TABLE)
/* Structure for z_once(), which must be initialized with Z_ONCE_INIT. */
typedef struct z_once_s z_once_t;
void ZLIB_INTERNAL z_once(z_once_t *state, void (*init)(void));
#if defined(__STDC__) && __STDC_VERSION__ >= 201112L && \
!defined(__STDC_NO_ATOMICS__)
#include <stdatomic.h>
struct z_once_s {
atomic_flag begun;
atomic_int done;
};
#define Z_ONCE_INIT {ATOMIC_FLAG_INIT, 0}
#else /* no atomics! */
struct z_once_s {
volatile int begun;
volatile int done;
};
#define Z_ONCE_INIT {0, 0}
#endif
#endif
#endif /* ZUTIL_H */
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