/*
 * Copyright (c) 2003, Adam Dunkels.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above
 *    copyright notice, this list of conditions and the following
 *    disclaimer in the documentation and/or other materials provided
 *    with the distribution.
 * 3. The name of the author may not be used to endorse or promote
 *    products derived from this software without specific prior
 *    written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This file is part of the Contiki desktop OS
 *
 *
 */

/**
 * \file
 * Default definitions of C compiler quirk work-arounds.
 * \author Adam Dunkels <adam@dunkels.com>
 *
 * This file is used for making use of extra functionality of some C
 * compilers used for Contiki, and defining work-arounds for various
 * quirks and problems with some other C compilers.
 */

#ifndef CC_H_
#define CC_H_

#include "contiki-conf.h"
#include "sys/cc-gcc.h"

/**
 * Configure if the C compiler supports the "register" keyword for
 * function arguments.
 */
#if CC_CONF_REGISTER_ARGS
#define CC_REGISTER_ARG register
#else /* CC_CONF_REGISTER_ARGS */
#define CC_REGISTER_ARG
#endif /* CC_CONF_REGISTER_ARGS */

/**
 * Configure if the C compiler supports the arguments for function
 * pointers.
 */
#if CC_CONF_FUNCTION_POINTER_ARGS
#define CC_FUNCTION_POINTER_ARGS 1
#else /* CC_CONF_FUNCTION_POINTER_ARGS */
#define CC_FUNCTION_POINTER_ARGS 0
#endif /* CC_CONF_FUNCTION_POINTER_ARGS */

/**
 * Configure if the C compiler have problems with const function pointers
 */
#ifdef CC_CONF_CONST_FUNCTION_BUG
#define CC_CONST_FUNCTION
#else /* CC_CONF_CONST_FUNCTION_BUG */
#define CC_CONST_FUNCTION const
#endif /* CC_CONF_CONST_FUNCTION_BUG */

/**
 * Configure work-around for unsigned char bugs with sdcc.
 */
#if CC_CONF_UNSIGNED_CHAR_BUGS
#define CC_UNSIGNED_CHAR_BUGS 1
#else /* CC_CONF_UNSIGNED_CHAR_BUGS */
#define CC_UNSIGNED_CHAR_BUGS 0
#endif /* CC_CONF_UNSIGNED_CHAR_BUGS */

/**
 * Configure if C compiler supports double hash marks in C macros.
 */
#if CC_CONF_DOUBLE_HASH
#define CC_DOUBLE_HASH 1
#else /* CC_CONF_DOUBLE_HASH */
#define CC_DOUBLE_HASH 0
#endif /* CC_CONF_DOUBLE_HASH */

#ifdef CC_CONF_INLINE
#define CC_INLINE CC_CONF_INLINE
#else /* CC_CONF_INLINE */
#define CC_INLINE
#endif /* CC_CONF_INLINE */

#ifdef CC_CONF_ALIGN
#define CC_ALIGN(n) CC_CONF_ALIGN(n)
#endif /* CC_CONF_INLINE */

/**
 * Configure if the C compiler supports functions that are not meant to return
 * e.g. with __attribute__((__noreturn__))
 */
#ifdef CC_CONF_NORETURN
#define CC_NORETURN CC_CONF_NORETURN
#else
#define CC_NORETURN
#endif /* CC_CONF_NORETURN */


#ifdef CC_CONF_UNUSED
#define CC_UNUSED CC_CONF_UNUSED
#else /* CC_CONF_UNUSED */
#define CC_UNUSED
#endif /* CC_CONF_UNUSED */

#ifdef CC_CONF_WEAK
#define CC_WEAK CC_CONF_WEAK
#else /* CC_CONF_WEAK */
#define CC_WEAK
#endif /* CC_CONF_WEAK */


/**
 * Configure if the C compiler supports marking functions as deprecated
 * e.g. with __attribute__((deprecated))
 */
#ifdef CC_CONF_DEPRECATED
#define CC_DEPRECATED(msg) CC_CONF_DEPRECATED(msg)
#else
#define CC_DEPRECATED(msg)
#endif /* CC_CONF_DEPRECATED */

/**
 * Configure if the C compiler supports the assignment of struct value.
 */
#ifdef CC_CONF_ASSIGN_AGGREGATE
#define CC_ASSIGN_AGGREGATE(dest, src)	CC_CONF_ASSIGN_AGGREGATE(dest, src)
#else /* CC_CONF_ASSIGN_AGGREGATE */
#define CC_ASSIGN_AGGREGATE(dest, src)	*dest = *src
#endif /* CC_CONF_ASSIGN_AGGREGATE */

#if CC_CONF_NO_VA_ARGS
#define CC_NO_VA_ARGS CC_CONF_VA_ARGS
#endif

/** \def CC_ACCESS_NOW(x)
 * This macro ensures that the access to a non-volatile variable can
 * not be reordered or optimized by the compiler.
 * See also https://lwn.net/Articles/508991/ - In Linux the macro is
 * called ACCESS_ONCE
 * The type must be passed, because the typeof-operator is a gcc
 * extension
 */

#define CC_ACCESS_NOW(type, variable) (*(volatile type *)&(variable))

#ifndef NULL
#define NULL 0
#endif /* NULL */

#ifndef MAX
#define MAX(a,b)             \
({                           \
    __typeof__ (a) _a = (a); \
    __typeof__ (b) _b = (b); \
    _a > _b ? _a : _b;       \
})
#endif

#ifndef MIN
#define MIN(a,b)             \
({                           \
    __typeof__ (a) _a = (a); \
    __typeof__ (b) _b = (b); \
    _a < _b ? _a : _b;       \
})
#endif

#ifndef ABS
#define ABS(a)              \
({                           \
    __typeof__ (a) _a = (a); \
    _a >= 0 ? _a : -_a;      \
})
#endif


#define CC_CONCAT2(s1, s2) s1##s2
/**
 * A C preprocessing macro for concatenating two preprocessor tokens.
 *
 * We need use two macros (CC_CONCAT and CC_CONCAT2) in order to allow
 * concatenation of two \#defined macros.
 */
#define CC_CONCAT(s1, s2) CC_CONCAT2(s1, s2)
#define CC_CONCAT_EXT_2(s1, s2) CC_CONCAT2(s1, s2)

/**
 * A C preprocessing macro for concatenating three preprocessor tokens.
 */
#define CC_CONCAT3(s1, s2, s3) s1##s2##s3
#define CC_CONCAT_EXT_3(s1, s2, s3) CC_CONCAT3(s1, s2, s3)

#endif /* CC_H_ */
