nasm/compiler.h
H. Peter Anvin 9656a581cd compiler.h: add offsetof() and container_of()
offsetof() is a C99 construct; provided here as an ersatz for older
systems.

container_of() is a nonstandard but highly useful construct, which
allows data structure control items like tree structures to be
embedded in larger data structures without the penalty of extra
pointers and allocations.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-30 10:54:55 -07:00

151 lines
3.9 KiB
C

/* ----------------------------------------------------------------------- *
*
* Copyright 2007-2008 The NASM Authors - All Rights Reserved
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the license given in the file "LICENSE"
* distributed in the NASM archive.
*
* ----------------------------------------------------------------------- */
/*
* compiler.h
*
* Compiler-specific macros for NASM. Feel free to add support for
* other compilers in here.
*
* This header file should be included before any other header.
*/
#ifndef NASM_COMPILER_H
#define NASM_COMPILER_H 1
#ifdef HAVE_CONFIG_H
# include "config.h"
/* autoconf doesn't define these if they are redundant, but we want to
be able to #ifdef them... */
#else
/* Default these to unsupported unless we have config.h */
# ifndef inline
# define inline
# endif
# ifndef restrict
# define restrict
# endif
#endif /* HAVE_CONFIG_H */
/* This is required to get the standard <inttypes.h> macros when compiling
with a C++ compiler. This must be defined *before* <inttypes.h> is
included, directly or indirectly. */
#define __STDC_CONSTANT_MACROS 1
#define __STDC_LIMIT_MACROS 1
#define __STDC_FORMAT_MACROS 1
#ifdef __GNUC__
# if __GNUC__ >= 4
# define HAVE_GNUC_4
# endif
# if __GNUC__ >= 3
# define HAVE_GNUC_3
# endif
#endif
#ifdef __GNUC__
# define _unused __attribute__((unused))
#else
# define _unused
#endif
/* Some versions of MSVC have these only with underscores in front */
#include <stddef.h>
#include <stdarg.h>
#include <stdio.h>
#ifndef HAVE_SNPRINTF
# ifdef HAVE__SNPRINTF
# define snprintf _snprintf
# else
int snprintf(char *, size_t, const char *, ...);
# endif
#endif
#ifndef HAVE_VSNPRINTF
# ifdef HAVE__VSNPRINT
# define vsnprintf _vsnprintf
# else
int vsnprintf(char *, size_t, const char *, va_list);
# endif
#endif
#ifndef __cplusplus /* C++ has false, true, bool as keywords */
# ifdef HAVE_STDBOOL_H
# include <stdbool.h>
# else
/* This is sort of dangerous, since casts will behave different than
casting to the standard boolean type. Always use !!, not (bool). */
typedef enum bool { false, true } bool;
# endif
#endif
/* Provide a substitute for offsetof() if we don't have one. This
variant works on most (but not *all*) systems... */
#ifndef offsetof
# define offsetof(t,m) ((size_t)&(((t *)0)->m))
#endif
/* The container_of construct: if p is a pointer to member m of
container class c, then return a pointer to the container of which
*p is a member. */
#ifndef container_of
# define container_of(p, c, m) ((c *)((char *)(p) - offsetof(c,m)))
#endif
/* Some misguided platforms hide the defs for these */
#if defined(HAVE_STRCASECMP) && !HAVE_DECL_STRCASECMP
int strcasecmp(const char *, const char *);
#endif
#if defined(HAVE_STRICMP) && !HAVE_DECL_STRICMP
int stricmp(const char *, const char *);
#endif
#if defined(HAVE_STRNCASECMP) && !HAVE_DECL_STRNCASECMP
int strncasecmp(const char *, const char *, size_t);
#endif
#if defined(HAVE_STRNICMP) && !HAVE_DECL_STRNICMP
int strnicmp(const char *, const char *, size_t);
#endif
#if defined(HAVE_STRSEP) && !HAVE_DECL_STRSEP
char *strsep(char **, const char *);
#endif
/*
* Define this to 1 for faster performance if this is a littleendian
* platform which can do unaligned memory references. It is safe
* to leave it defined to 0 even if that is true.
*/
#if defined(__386__) || defined(__i386__) || defined(__x86_64__)
# define X86_MEMORY 1
# ifndef WORDS_LITTLEENDIAN
# define WORDS_LITTLEENDIAN 1
# endif
#else
# define X86_MEMORY 0
#endif
/*
* Hints to the compiler that a particular branch of code is more or
* less likely to be taken.
*/
#if defined(__GNUC__) && __GNUC__ >= 3
# define likely(x) __builtin_expect(!!(x), 1)
# define unlikely(x) __builtin_expect(!!(x), 0)
#else
# define likely(x) (!!(x))
# define unlikely(x) (!!(x))
#endif
#endif /* NASM_COMPILER_H */