weston/shared/helpers.h
Leandro Ribeiro 58393ca733 shared/helpers: fix ARRAY_COPY macro
In commit "backend-drm: simplify compile time array copy", the macro
ARRAY_COPY was introduced.

The macro STRING was accidentally introduced in the same commit, and as
it is completely unnecessary, remove it.

Also, memcpy was copying from src to dst, and it should do the opposite.
So fix it.

Signed-off-by: Leandro Ribeiro <leandro.ribeiro@collabora.com>
2021-04-28 11:35:28 -03:00

167 lines
4.5 KiB
C

/*
* 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
#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
/**
* 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
#ifdef __cplusplus
}
#endif
#endif /* WESTON_HELPERS_H */