macros.h File Reference

Common and handy function macros. More...

#include <cfg/compiler.h>

Go to the source code of this file.

Defines
#define	MINMAX(min, x, max)   (MIN(MAX(min, x), max))
	Bound x between min and max.
#define	SHUFFLE(array, len)
	Shuffle the content of array that counts len elements.
#define	SWAP_T(a, b, T)
	Macro to swap a with b, with explicit type T for dumb C89 compilers.
#define	BV(x)   (1<<(x))
	Convert a bit value to a binary flag.
#define	BV32(x)   ((uint32_t)1<<(x))
	Same as BV() but with 32 bit result.
#define	BV16(x)   ((uint16_t)1<<(x))
	Same as BV() but with 16 bit result.
#define	BV8(x)   ((uint8_t)1<<(x))
	Same as BV() but with 8 bit result.
#define	DIV_ROUND(dividend, divisor)   (((dividend) + (divisor) / 2) / (divisor))
	Perform an integer division rounding the result to the nearest int value.
#define	ROUND_UP2(x, pad)   (((x) + ((pad) - 1)) & ~((pad) - 1))
	Round up x to an even multiple of the 2's power pad.
#define	IS_POW2(x)   (!(bool)((x) & ((x)-1)))
	Check if x is an integer power of 2.
#define	UINT8_LOG2(x)
	Calculate a compile-time log2 for a uint8_t.
#define	UINT16_LOG2(x)   ((x < 256) ? UINT8_LOG2(x) : UINT8_LOG2((x) >> 8) + 8)
	Calculate a compile-time log2 for a uint16_t.
#define	UINT32_LOG2(x)   ((x < 65536UL) ? UINT16_LOG2(x) : UINT16_LOG2((x) >> 16) + 16)
	Calculate a compile-time log2 for a uint32_t.
#define	MAKE_ID(a, b, c, d)
	Make an id from 4 letters, useful for file formats and kfile ids.
Integer round macros.
Round x to a multiple of base. Note: If x is signed these macros generate a lot of code.
#define	ROUND_DOWN(x, base)   ( (x) - ((x) % (base)) )
#define	ROUND_UP(x, base)   ( ((x) + (base) - 1) - (((x) + (base) - 1) % (base)) )
#define	ROUND_NEAREST(x, base)   ( ((x) + (base) / 2) - (((x) + (base) / 2) % (base)) )
#define	ROTR(var, rot)   (((var) >> (rot)) | ((var) << ((sizeof(var) * 8) - (rot))))
	Macro for rotating bit left or right.
Typedefs
typedef uint32_t	id_t
	Type for id generated by MAKE_ID().

---

Detailed Description

Common and handy function macros.

Version:

Id

macros.h 2506 2009-04-15 08:29:07Z duplo

Author:

Bernie Innocenti <bernie@codewiz.org>

Giovanni Bajo <rasky@develer.com>

Definition in file macros.h.

---

Define Documentation

#define BV

(

x

)

(1<<(x))

Convert a bit value to a binary flag.

Definition at line 160 of file macros.h.

#define DIV_ROUND	(	dividend,
		divisor		)	(((dividend) + (divisor) / 2) / (divisor))

Perform an integer division rounding the result to the nearest int value.

Note:

divisor should preferibly be a costant, otherwise this macro generates 2 division. Also divisor is evaluated twice.

Definition at line 177 of file macros.h.

#define IS_POW2

(

x

)

(!(bool)((x) & ((x)-1)))

Check if x is an integer power of 2.

Definition at line 195 of file macros.h.

#define MINMAX	(	min,
		x,
		max		)	(MIN(MAX(min, x), max))

Bound x between min and max.

Definition at line 99 of file macros.h.

#define ROUND_UP2	(	x,
		pad		)	(((x) + ((pad) - 1)) & ~((pad) - 1))

Round up x to an even multiple of the 2's power pad.

Definition at line 180 of file macros.h.

#define SWAP_T	(	a,
		b,
		T		)

Value:

do { \
        T tmp; \
        ASSERT_TYPE_IS(a, T); \
        ASSERT_TYPE_IS(b, T); \
        tmp = (a); \
        (a) = (b); \
        (b) = tmp; \
    } while (0)

Macro to swap a with b, with explicit type T for dumb C89 compilers.

Note:

Arguments are evaluated multiple times.

Definition at line 147 of file macros.h.