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/*************************************************************************
* Copyright (C) 2008 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of The Sandglass Library. *
* *
* The Sandglass Library is free software; you can redistribute it *
* and/or modify it under the terms of the GNU Lesser General Public *
* License as published by the Free Software Foundation; either version *
* 3 of the License, or (at your option) any later version. *
* *
* The Sandglass Library is distributed in the hope that it will be *
* useful, but WITHOUT ANY WARRANTY; without even the implied warranty *
* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU *
* Lesser General Public License for more details. *
* *
* You should have received a copy of the GNU Lesser General Public *
* License along with this program. If not, see *
* <http://www.gnu.org/licenses/>. *
*************************************************************************/
#include "sandglass_impl.h"
#include "sandglass.h"
#include <unistd.h>
#include <time.h>
#include <errno.h>
int
sandglass_init_introspective(sandglass_t *sandglass, sandglass_resolution_t res)
{
switch (res) {
case SANDGLASS_CPUTIME:
if (sysconf(_SC_THREAD_CPUTIME) > 0 || sysconf(_SC_CPUTIME) > 0) {
sandglass->freq = 1e9;
sandglass->loops = 1;
} else {
errno = ENOTSUP;
return -1;
}
break;
case SANDGLASS_SYSTEM:
sandglass->freq = CLOCKS_PER_SEC;
sandglass->loops = 1;
break;
default:
errno = EINVAL;
return -1;
}
sandglass->incrementation = SANDGLASS_INTROSPECTIVE;
sandglass->resolution = res;
return 0;
}
int
sandglass_init_monotonic(sandglass_t *sandglass, sandglass_resolution_t res)
{
switch (res) {
case SANDGLASS_CPUTIME:
#ifdef SANDGLASS_TSC
sandglass->freq = sandglass_tsc_freq();
sandglass->loops = sandglass_tsc_loops();
break;
#else
errno = ENOTSUP;
return -1;
#endif
case SANDGLASS_SYSTEM:
sandglass->freq = 1e9;
sandglass->loops = 1;
break;
default:
errno = EINVAL;
return -1;
}
sandglass->incrementation = SANDGLASS_MONOTONIC;
sandglass->resolution = res;
return 0;
}
/* Store a timer value in sandglass->grains */
static int sandglass_real_gettime(sandglass_t *sandglass);
/* Start timing */
int
sandglass_begin(sandglass_t *sandglass)
{
return sandglass_real_gettime(sandglass);
}
/* Finish timing */
int
sandglass_elapse(sandglass_t *sandglass)
{
long oldgrains = sandglass->grains;
if (sandglass_real_gettime(sandglass))
return -1;
sandglass->grains -= oldgrains;
if (sandglass->grains < 0)
/* Magical correction for timespec-based grains */
sandglass->grains += sandglass->adjustment;
return 0;
}
/* Store a timer value in sandglass->grains */
static int
sandglass_real_gettime(sandglass_t *sandglass)
{
struct timespec ts;
clock_t clock_ticks;
switch (sandglass->incrementation) {
case SANDGLASS_MONOTONIC:
switch (sandglass->resolution) {
case SANDGLASS_CPUTIME:
#ifdef SANDGLASS_TSC
sandglass->grains = sandglass_get_tsc();
break;
#else
errno = ENOTSUP;
return -1;
#endif
case SANDGLASS_SYSTEM:
if (sysconf(_SC_MONOTONIC_CLOCK) > 0) {
if (clock_gettime(CLOCK_MONOTONIC, &ts) != 0)
return -1;
} else {
if (clock_gettime(CLOCK_REALTIME, &ts) != 0)
return -1;
}
sandglass->grains = ts.tv_nsec;
sandglass->adjustment = 1000000000L;
break;
default:
errno = EINVAL;
return -1;
}
break;
case SANDGLASS_INTROSPECTIVE:
switch (sandglass->resolution) {
case SANDGLASS_CPUTIME:
if (sysconf(_SC_THREAD_CPUTIME) > 0) {
if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &ts) != 0)
return -1;
} else if (sysconf(_SC_CPUTIME) > 0) {
if (clock_gettime(CLOCK_PROCESS_CPUTIME_ID, &ts) != 0)
return -1;
} else {
errno = EINVAL;
return -1;
}
sandglass->grains = ts.tv_nsec;
sandglass->adjustment = 1000000000L;
break;
case SANDGLASS_SYSTEM:
if ((clock_ticks = clock()) == -1)
return -1;
sandglass->grains = clock_ticks;
break;
default:
errno = EINVAL;
return -1;
}
break;
default:
errno = EINVAL;
return -1;
}
return 0;
}
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