serval-dna/asterisk_include/asterisk/time.h
2011-03-21 13:08:35 +10:30

145 lines
3.5 KiB
C

/*
* Asterisk -- An open source telephony toolkit.
*
* Copyright (C) 1999 - 2005, Digium, Inc.
*
* Mark Spencer <markster@digium.com>
*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2. See the LICENSE file
* at the top of the source tree.
*/
/*! \file
* \brief Time-related functions and macros
*/
#ifndef _ASTERISK_TIME_H
#define _ASTERISK_TIME_H
#include <sys/time.h>
#include <stdlib.h>
#include "asterisk/inline_api.h"
/* We have to let the compiler learn what types to use for the elements of a
struct timeval since on linux, it's time_t and suseconds_t, but on *BSD,
they are just a long. */
extern struct timeval tv;
typedef typeof(tv.tv_sec) ast_time_t;
typedef typeof(tv.tv_usec) ast_suseconds_t;
/*!
* \brief Computes the difference (in milliseconds) between two \c struct \c timeval instances.
* \param end end of the time period
* \param start beginning of the time period
* \return the difference in milliseconds
*/
AST_INLINE_API(
int ast_tvdiff_ms(struct timeval end, struct timeval start),
{
/* the offset by 1,000,000 below is intentional...
it avoids differences in the way that division
is handled for positive and negative numbers, by ensuring
that the divisor is always positive
*/
return ((end.tv_sec - start.tv_sec) * 1000) +
(((1000000 + end.tv_usec - start.tv_usec) / 1000) - 1000);
}
)
/*!
* \brief Returns true if the argument is 0,0
*/
AST_INLINE_API(
int ast_tvzero(const struct timeval t),
{
return (t.tv_sec == 0 && t.tv_usec == 0);
}
)
/*!
* \brief Compres two \c struct \c timeval instances returning
* -1, 0, 1 if the first arg is smaller, equal or greater to the second.
*/
AST_INLINE_API(
int ast_tvcmp(struct timeval _a, struct timeval _b),
{
if (_a.tv_sec < _b.tv_sec)
return -1;
if (_a.tv_sec > _b.tv_sec)
return 1;
/* now seconds are equal */
if (_a.tv_usec < _b.tv_usec)
return -1;
if (_a.tv_usec > _b.tv_usec)
return 1;
return 0;
}
)
/*!
* \brief Returns true if the two \c struct \c timeval arguments are equal.
*/
AST_INLINE_API(
int ast_tveq(struct timeval _a, struct timeval _b),
{
return (_a.tv_sec == _b.tv_sec && _a.tv_usec == _b.tv_usec);
}
)
/*!
* \brief Returns current timeval. Meant to replace calls to gettimeofday().
*/
AST_INLINE_API(
struct timeval ast_tvnow(void),
{
struct timeval t;
gettimeofday(&t, NULL);
return t;
}
)
/*!
* \brief Returns the sum of two timevals a + b
*/
struct timeval ast_tvadd(struct timeval a, struct timeval b);
/*!
* \brief Returns the difference of two timevals a - b
*/
struct timeval ast_tvsub(struct timeval a, struct timeval b);
/*!
* \brief Returns a timeval from sec, usec
*/
AST_INLINE_API(
struct timeval ast_tv(ast_time_t sec, ast_suseconds_t usec),
{
struct timeval t;
t.tv_sec = sec;
t.tv_usec = usec;
return t;
}
)
/*!
* \brief Returns a timeval corresponding to the duration of n samples at rate r.
* Useful to convert samples to timevals, or even milliseconds to timevals
* in the form ast_samp2tv(milliseconds, 1000)
*/
AST_INLINE_API(
struct timeval ast_samp2tv(unsigned int _nsamp, unsigned int _rate),
{
return ast_tv(_nsamp / _rate, ((_nsamp % _rate) * (4000000 / _rate)) / 4); /* this calculation is accurate up to 32000Hz. */
}
)
#endif /* _ASTERISK_TIME_H */