/* Copyright 2013 The Chromium OS Authors. All rights reserved.
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

/* Handy clever tricks */

#ifndef __CROS_EC_COMPILE_TIME_MACROS_H
#define __CROS_EC_COMPILE_TIME_MACROS_H

/* Test an important condition at compile time, not run time */
#define _BA1_(cond, file, line, msg) \
	_Static_assert(cond, file ":" #line ": " msg)
#define _BA0_(c, f, l, msg) _BA1_(c, f, l, msg)
/* Pass in an option message to display after condition */
#define BUILD_ASSERT(cond, ...) _BA0_(cond, __FILE__, __LINE__, __VA_ARGS__)

/*
 * Test an important condition inside code path at run time, taking advantage of
 * -Werror=div-by-zero.
 */
#define BUILD_CHECK_INLINE(value, cond_true) ((value) / (!!(cond_true)))

/* Check that the value is an array (not a pointer) */
#define _IS_ARRAY(arr) \
	!__builtin_types_compatible_p(typeof(arr), typeof(&(arr)[0]))

/**
 * ARRAY_SIZE - Number of elements in an array.
 *
 * This version is type-safe and will not allow pointers, causing a
 * compile-time divide by zero error if a pointer is passed.
 */
#define ARRAY_SIZE(arr) \
	BUILD_CHECK_INLINE(sizeof(arr) / sizeof((arr)[0]), _IS_ARRAY(arr))

/* Make for loops that iterate over pointers to array entries more readable */
#define ARRAY_BEGIN(array)                                                   \
	({                                                                   \
		BUILD_ASSERT(_IS_ARRAY(array),                               \
			     "ARRAY_BEGIN is only compatible with arrays."); \
		(array);                                                     \
	})
#define ARRAY_END(array) ((array) + ARRAY_SIZE(array))

/* Just in case - http://gcc.gnu.org/onlinedocs/gcc/Offsetof.html */
#ifndef offsetof
#define offsetof(type, member)  __builtin_offsetof(type, member)
#endif

#define member_size(type, member) sizeof(((type *)0)->member)

/*
 * Bit operation macros.
 */
#define BIT(nr)			(1U << (nr))
#define BIT_ULL(nr)		(1ULL << (nr))

/*
 * Create a bit mask from least significant bit |l|
 * to bit |h|, inclusive.
 *
 * Examples:
 * GENMASK(31, 0) ==> 0xFF_FF_FF_FF
 * GENMASK(3, 0)  ==> 0x00_00_00_0F
 * GENMASK(7, 4)  ==> 0x00_00_00_F0
 * GENMASK(b, b)  ==> BIT(b)
 *
 * Note that we shift after using BIT() to avoid compiler
 * warnings for BIT(31+1).
 */
#define GENMASK(h, l)     (((BIT(h)<<1)     - 1) ^ (BIT(l)     - 1))
#define GENMASK_ULL(h, l) (((BIT_ULL(h)<<1) - 1) ^ (BIT_ULL(l) - 1))

#endif /* __CROS_EC_COMPILE_TIME_MACROS_H */