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/*
* Copyright © 2015 Samsung Electronics Co., Ltd
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef WESTON_HELPERS_H
#define WESTON_HELPERS_H
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
/**
* @file
* Simple misc helper macros.
*/
/**
* Compile-time computation of number of items in a hardcoded array.
*
* @param a the array being measured.
* @return the number of items hardcoded into the array.
*/
#ifndef ARRAY_LENGTH
#define ARRAY_LENGTH(a) (sizeof (a) / sizeof (a)[0])
#endif
/**
* Compile-time copy of hardcoded arrays.
*
* @param dst the array to copy to.
* @param src the source array.
*/
#ifndef ARRAY_COPY
#define ARRAY_COPY(dst, src) \
do { \
static_assert(ARRAY_LENGTH(src) == ARRAY_LENGTH(dst), \
"src and dst sizes must match"); \
static_assert(sizeof(src) == sizeof(dst), \
"src and dst sizes must match"); \
memcpy((dst), (src), sizeof(src)); \
} while (0)
#endif
/**
* Returns the smaller of two values.
*
* @param x the first item to compare.
* @param y the second item to compare.
* @return the value that evaluates to lesser than the other.
*/
#ifndef MIN
#define MIN(x,y) (((x) < (y)) ? (x) : (y))
#endif
/**
* Returns the bigger of two values.
*
* @param x the first item to compare.
* @param y the second item to compare.
* @return the value that evaluates to more than the other.
*/
#ifndef MAX
#define MAX(x,y) (((x) > (y)) ? (x) : (y))
#endif
/**
* Clips the value to the maximum to the first item provided.
*
* @param c the first item to compare.
* @param x the second item to compare.
* @param y the third item to compare.
* @return the value that evaluates to lesser than the maximum of
* the two other parameters.
*/
#ifndef CLIP
#define CLIP(c, x, y) MIN(MAX(c, x), y)
#endif
/**
* Divides two integers, rounding up.
*
* @param n the numerator to divide.
* @param d the denominator to divide by.
* @return the rounded up result of the division n / d.
*/
#define DIV_ROUND_UP(n, d) \
({ typeof(d) tmp = (d); ((n) + tmp - 1) / tmp; })
/**
* Returns a pointer to the containing struct of a given member item.
*
* To demonstrate, the following example retrieves a pointer to
* `example_container` given only its `destroy_listener` member:
*
* @code
* struct example_container {
* struct wl_listener destroy_listener;
* // other members...
* };
*
* void example_container_destroy(struct wl_listener *listener, void *data)
* {
* struct example_container *ctr;
*
* ctr = wl_container_of(listener, ctr, destroy_listener);
* // destroy ctr...
* }
* @endcode
*
* @param ptr A valid pointer to the contained item.
*
* @param type A pointer to the type of content that the list item
* stores. Type does not need be a valid pointer; a null or
* an uninitialised pointer will suffice.
*
* @param member The named location of ptr within the sample type.
*
* @return The container for the specified pointer.
*/
#ifndef container_of
#define container_of(ptr, type, member) ({ \
const __typeof__( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})
#endif
/**
* Build-time static assertion support
*
* A build-time equivalent to assert(), will generate a compilation error
* if the supplied condition does not evaluate true.
*
* The following example demonstrates use of static_assert to ensure that
* arrays which are supposed to mirror each other have a consistent
* size.
*
* This is only a fallback definition; support must be provided by the
* compiler itself.
*
* @code
* int small[4];
* long expanded[4];
*
* static_assert(ARRAY_LENGTH(small) == ARRAY_LENGTH(expanded),
* "size mismatch between small and expanded arrays");
* for (i = 0; i < ARRAY_LENGTH(small); i++)
* expanded[i] = small[4];
* @endcode
*
* @param cond Expression to check for truth
* @param msg Message to print on failure
*/
#ifndef static_assert
# ifdef _Static_assert
# define static_assert(cond, msg) _Static_assert(cond, msg)
# else
# define static_assert(cond, msg)
# endif
#endif
/** Ensure argument is of given type */
#ifndef TYPEVERIFY
#define TYPEVERIFY(type, arg) ({ \
typeof(arg) tmp___ = (arg); \
(void)((type)0 == tmp___); \
tmp___; })
#endif
/** Private symbol export for tests
*
* Symbols tagged with this are private libweston functions that are exported
* only for the test suite to allow unit testing. Nothing else internal or
* external to libweston is allowed to use these exports.
*
* Therefore, the ABI exported with this tag is completely unversioned, and
* is allowed to break at any time without any indication or version bump.
* This may happen in all git branches, including stable release branches.
*/
#define WESTON_EXPORT_FOR_TESTS __attribute__ ((visibility("default")))
static inline uint64_t
u64_from_u32s(uint32_t hi, uint32_t lo)
{
return ((uint64_t)hi << 32) + lo;
}
#ifndef __has_builtin
# define __has_builtin(x) 0
#endif
#if defined(HAVE_UNREACHABLE) || __has_builtin(__builtin_unreachable)
#define unreachable(str) \
do { \
assert(!str); \
__builtin_unreachable(); \
} while (0)
#elif defined (_MSC_VER)
#define unreachable(str) \
do { \
assert(!str); \
__assume(0); \
} while (0)
#else
#define unreachable(str) assert(!str)
#endif
#ifdef __cplusplus
}
#endif
#endif /* WESTON_HELPERS_H */
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