/*
 * Copyright (c) 2004-2005 The Trustees of Indiana University.
 *                         All rights reserved.
 * Copyright (c) 2004-2005 The Trustees of the University of Tennessee.
 *                         All rights reserved.
 * Copyright (c) 2004-2005 High Performance Computing Center Stuttgart, 
 *                         University of Stuttgart.  All rights reserved.
 * Copyright (c) 2004-2005 The Regents of the University of California.
 *                         All rights reserved.
 * $COPYRIGHT$
 * 
 * Additional copyrights may follow
 * 
 * $HEADER$
 */

#include "ompi_config.h"

#include "opal/mca/timer/timer.h"
#include "opal/mca/timer/linux/timer_linux.h"
#include "opal/include/constants.h"

opal_timer_t opal_timer_linux_freq;

static int opal_timer_linux_open(void);

const opal_timer_base_component_1_0_0_t mca_timer_linux_component = {
    /* First, the mca_component_t struct containing meta information
       about the component itself */
    {
        /* Indicate that we are a timer v1.0.0 component (which also
           implies a specific MCA version) */
        OPAL_TIMER_BASE_VERSION_1_0_0,

        /* Component name and version */
        "linux",
        OPAL_MAJOR_VERSION,
        OPAL_MINOR_VERSION,
        OPAL_RELEASE_VERSION,

        /* Component open and close functions */
        opal_timer_linux_open,
        NULL
    },

    /* Next the MCA v1.0.0 component meta data */
    {
        /* Whether the component is checkpointable or not */
        true
    },
};

static char *
find_info(FILE* fp, char *str, char *buf, size_t buflen)
{
    char *tmp;

    while (NULL != fgets(buf, 1024, fp)) {
        if (strncmp(buf, str, strlen(str)) == 0) {
            /* we found the line.  Now eat everything up to,
               including, and one past the : */
            for (tmp = buf ; (*tmp != '\0') && (*tmp != ':') ; ++tmp) ;
            for ( ++tmp ; *tmp == ' ' ; ++tmp);
            if (NULL != tmp && '\0' != *tmp) {
                return tmp;
            }
        }
    }

    return NULL;
}

int
opal_timer_linux_open(void)
{
    FILE *fp;
    char *loc;
    float cpu_f;
    int ret;
    char buf[1024];

    fp = fopen("/proc/cpuinfo", "r");
    if (NULL == fp) {
        return OPAL_ERR_IN_ERRNO;
    }

    loc = find_info(fp, "cpu MHz", buf, 1024);
    if (NULL == loc) {
        return OPAL_ERR_NOT_FOUND;
    }

    ret = sscanf(loc, "%f", &cpu_f);
    if (1 != ret) return OPAL_ERR_NOT_FOUND;

    /* numer is in MHz - convert to Hz and make an integer */
    opal_timer_linux_freq = (opal_timer_t) cpu_f * 1000000;

    return OPAL_SUCCESS;
}