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/*-
 *   BSD LICENSE
 * 
 *   Copyright(c) 2010-2013 Intel Corporation. All rights reserved.
 *   All rights reserved.
 * 
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 * 
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 * 
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "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 COPYRIGHT
 *   OWNER OR CONTRIBUTORS 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.
 */

#ifndef _RTE_COMMON_H_
#define _RTE_COMMON_H_

/**
 * @file
 *
 * Generic, commonly-used macro and inline function definitions
 * for Intel DPDK.
 */

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>
#include <stdlib.h>
#include <ctype.h>
#include <errno.h>

/*********** Macros to eliminate unused variable warnings ********/

/**
 * short definition to mark a function parameter unused
 */
#define __rte_unused __attribute__((__unused__))

/**
 * definition to mark a variable or function parameter as used so
 * as to avoid a compiler warning
 */
#define RTE_SET_USED(x) (void)(x)

/*********** Macros for pointer arithmetic ********/

/**
 * add a byte-value offset from a pointer
 */
#define RTE_PTR_ADD(ptr, x) ((typeof(ptr))((uintptr_t)ptr + (x)))

/**
 * subtract a byte-value offset from a pointer
 */
#define RTE_PTR_SUB(ptr, x) ((typeof(ptr))((uintptr_t)ptr - (x)))

/**
 * get the difference between two pointer values, i.e. how far apart
 * in bytes are the locations they point two. It is assumed that
 * ptr1 is greater than ptr2.
 */
#define RTE_PTR_DIFF(ptr1, ptr2) ((uintptr_t)(ptr1) - (uintptr_t)(ptr2))

/*********** Macros/static functions for doing alignment ********/

/**
 * Function which rounds an unsigned int down to a given power-of-two value.
 * Takes uintptr_t types as parameters, as this type of operation is most
 * commonly done for pointer alignment. (See also RTE_ALIGN_FLOOR,
 * RTE_ALIGN_CEIL, RTE_ALIGN, RTE_PTR_ALIGN_FLOOR, RTE_PTR_ALIGN_CEL,
 * RTE_PTR_ALIGN macros)
 * @param ptr
 *   The value to be rounded down
 * @param align
 *   The power-of-two of which the result must be a multiple.
 * @return
 *   Function returns a properly aligned value where align is a power-of-two.
 *   If align is not a power-of-two, result will be incorrect.
 */
static inline uintptr_t
rte_align_floor_int(uintptr_t ptr, uintptr_t align)
{
	return (ptr & ~(align - 1));
}

/**
 * Macro to align a pointer to a given power-of-two. The resultant
 * pointer will be a pointer of the same type as the first parameter, and
 * point to an address no higher than the first parameter. Second parameter
 * must be a power-of-two value.
 */
#define RTE_PTR_ALIGN_FLOOR(ptr, align) \
	(typeof(ptr))rte_align_floor_int((uintptr_t)ptr, align)

/**
 * Macro to align a value to a given power-of-two. The resultant value
 * will be of the same type as the first parameter, and will be no
 * bigger than the first parameter. Second parameter must be a
 * power-of-two value.
 */
#define RTE_ALIGN_FLOOR(val, align) \
	(typeof(val))((val) & (~((typeof(val))((align) - 1))))

/**
 * Macro to align a pointer to a given power-of-two. The resultant
 * pointer will be a pointer of the same type as the first parameter, and
 * point to an address no lower than the first parameter. Second parameter
 * must be a power-of-two value.
 */
#define RTE_PTR_ALIGN_CEIL(ptr, align) \
	RTE_PTR_ALIGN_FLOOR(RTE_PTR_ADD(ptr, (align) - 1), align)

/**
 * Macro to align a value to a given power-of-two. The resultant value
 * will be of the same type as the first parameter, and will be no lower
 * than the first parameter. Second parameter must be a power-of-two
 * value.
 */
#define RTE_ALIGN_CEIL(val, align) \
	RTE_ALIGN_FLOOR(((val) + ((typeof(val)) (align) - 1)), align)

/**
 * Macro to align a pointer to a given power-of-two. The resultant
 * pointer will be a pointer of the same type as the first parameter, and
 * point to an address no lower than the first parameter. Second parameter
 * must be a power-of-two value.
 * This function is the same as RTE_PTR_ALIGN_CEIL
 */
#define RTE_PTR_ALIGN(ptr, align) RTE_PTR_ALIGN_CEIL(ptr, align)

/**
 * Macro to align a value to a given power-of-two. The resultant
 * value will be of the same type as the first parameter, and
 * will be no lower than the first parameter. Second parameter
 * must be a power-of-two value.
 * This function is the same as RTE_ALIGN_CEIL
 */
#define RTE_ALIGN(val, align) RTE_ALIGN_CEIL(val, align)

/**
 * Checks if a pointer is aligned to a given power-of-two value
 *
 * @param ptr
 *   The pointer whose alignment is to be checked
 * @param align
 *   The power-of-two value to which the ptr should be aligned
 *
 * @return
 *   True(1) where the pointer is correctly aligned, false(0) otherwise
 */
static inline int
rte_is_aligned(void *ptr, unsigned align)
{
	return RTE_PTR_ALIGN(ptr, align) == ptr;
}

/*********** Macros for compile type checks ********/

/**
 * Triggers an error at compilation time if the condition is true.
 */
#ifndef __OPTIMIZE__
#define RTE_BUILD_BUG_ON(condition) ((void)sizeof(char[1 - 2*!!(condition)]))
#else
extern int RTE_BUILD_BUG_ON_detected_error;
#define RTE_BUILD_BUG_ON(condition) do {             \
	((void)sizeof(char[1 - 2*!!(condition)]));   \
	if (condition)                               \
		RTE_BUILD_BUG_ON_detected_error = 1; \
} while(0)
#endif

/*********** Macros to work with powers of 2 ********/

/**
 * Returns true if n is a power of 2
 * @param n
 *     Number to check
 * @return 1 if true, 0 otherwise
 */
static inline int
rte_is_power_of_2(uint32_t n)
{
	return ((n-1) & n) == 0;
}

/**
 * Aligns input parameter to the next power of 2
 *
 * @param x
 *   The integer value to algin
 *
 * @return
 *   Input parameter aligned to the next power of 2
 */
static inline uint32_t
rte_align32pow2(uint32_t x)
{
	x--;
	x |= x >> 1;
	x |= x >> 2;
	x |= x >> 4;
	x |= x >> 8;
	x |= x >> 16;

	return x + 1;
}

/*********** Macros for calculating min and max **********/

/**
 * Macro to return the minimum of two numbers
 */
#define RTE_MIN(a, b) ({ \
		typeof (a) _a = (a); \
		typeof (b) _b = (b); \
		_a < _b ? _a : _b; \
	})

/**
 * Macro to return the maximum of two numbers
 */
#define RTE_MAX(a, b) ({ \
		typeof (a) _a = (a); \
		typeof (b) _b = (b); \
		_a > _b ? _a : _b; \
	})

/*********** Other general functions / macros ********/

#ifdef __SSE2__
#include <emmintrin.h>
/**
 * PAUSE instruction for tight loops (avoid busy waiting)
 */
static inline void
rte_pause (void)
{
	_mm_pause();
}
#else
static inline void
rte_pause(void) {}
#endif

/**
 * Searches the input parameter for the least significant set bit
 * (starting from zero).
 * If a least significant 1 bit is found, its bit index is returned.
 * If the content of the input parameter is zero, then the content of the return
 * value is undefined.
 * @param v
 *     input parameter, should not be zero.
 * @return
 *     least significant set bit in the input parameter.
 */
static inline uint32_t
rte_bsf32(uint32_t v)
{
	return (__builtin_ctz(v));
}

#ifndef offsetof
/** Return the offset of a field in a structure. */
#define offsetof(TYPE, MEMBER)  __builtin_offsetof (TYPE, MEMBER)
#endif

#define _RTE_STR(x) #x
/** Take a macro value and get a string version of it */
#define RTE_STR(x) _RTE_STR(x)

/**
 * Converts a numeric string to the equivalent uint64_t value.
 * As well as straight number conversion, also recognises the suffixes
 * k, m and g for kilobytes, megabytes and gigabytes respectively.
 *
 * If a negative number is passed in  i.e. a string with the first non-black
 * character being "-", zero is returned. Zero is also returned in the case of
 * an error with the strtoull call in the function.
 *
 * @param str
 *     String containing number to convert.
 * @return
 *     Number.
 */
static inline uint64_t
rte_str_to_size(const char *str)
{
	char *endptr;
	unsigned long long size;

	while (isspace((int)*str))
		str++;
	if (*str == '-')
		return 0;

	errno = 0;
	size = strtoull(str, &endptr, 0);
	if (errno)
		return 0;

	if (*endptr == ' ')
		endptr++; /* allow 1 space gap */

	switch (*endptr){
	case 'G': case 'g': size *= 1024; /* fall-through */
	case 'M': case 'm': size *= 1024; /* fall-through */
	case 'K': case 'k': size *= 1024; /* fall-through */
	default:
		break;
	}
	return size;
}

/**
 * Function to terminate the application immediately, printing an error
 * message and returning the exit_code back to the shell.
 *
 * This function never returns
 *
 * @param exit_code
 *     The exit code to be returned by the application
 * @param format
 *     The format string to be used for printing the message. This can include
 *     printf format characters which will be expanded using any further parameters
 *     to the function.
 */
void
rte_exit(int exit_code, const char *format, ...)
	__attribute__((noreturn))
	__attribute__((format(printf, 2, 3)));

#ifdef __cplusplus
}
#endif

#endif