/*

 * Copyright (c) 2011, 2012, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

#include <sys/time.h>

#include <mach/mach.h>

#include <mach/task_info.h>

JNIEXPORT jdouble JNICALL

(JNIEnv *env, jobject dummy)

{

    // This code is influenced by the darwin top source

    kern_return_t kr;

    mach_msg_type_number_t count;

    host_cpu_load_info_data_t load;

    static jlong last_used  = 0;

    static jlong last_total = 0;

    count = HOST_CPU_LOAD_INFO_COUNT;

    kr = host_statistics(mach_host_self(), HOST_CPU_LOAD_INFO, (host_info_t)&load, &count);

    if (kr != KERN_SUCCESS) {

        return -1;

    }

    jlong used  = load.cpu_ticks[CPU_STATE_USER] + load.cpu_ticks[CPU_STATE_NICE] + load.cpu_ticks[CPU_STATE_SYSTEM];

    jlong total = used + load.cpu_ticks[CPU_STATE_IDLE];

    if (last_used == 0 || last_total == 0) {

        // First call, just set the last values

        last_used  = used;

        last_total = total;

        // return 0 since we have no data, not -1 which indicates error

        return 0;

    }

    jlong used_delta  = used - last_used;

    jlong total_delta = total - last_total;

    jdouble cpu = (jdouble) used_delta / total_delta;

    last_used  = used;

    last_total = total;

    return cpu;

}

#define TIME_VALUE_TO_TIMEVAL(a, r) do {  \

     (r)->tv_sec = (a)->seconds;          \

     (r)->tv_usec = (a)->microseconds;    \

} while (0)

#define TIME_VALUE_TO_MICROSECONDS(TV) \

     ((TV).tv_sec * 1000 * 1000 + (TV).tv_usec)

JNIEXPORT jdouble JNICALL

(JNIEnv *env, jobject dummy)

{

    // This code is influenced by the darwin top source

    struct task_basic_info_64 task_info_data;

    struct task_thread_times_info thread_info_data;

    struct timeval user_timeval, system_timeval, task_timeval;

    struct timeval now;

    mach_port_t task = mach_task_self();

    kern_return_t kr;

    static jlong last_task_time = 0;

    static jlong last_time      = 0;

    mach_msg_type_number_t thread_info_count = TASK_THREAD_TIMES_INFO_COUNT;

    kr = task_info(task,

            TASK_THREAD_TIMES_INFO,

            (task_info_t)&thread_info_data,

            &thread_info_count);

    if (kr != KERN_SUCCESS) {

        // Most likely cause: |task| is a zombie.

        return -1;

    }

    mach_msg_type_number_t count = TASK_BASIC_INFO_64_COUNT;

    kr = task_info(task,

            TASK_BASIC_INFO_64,

            (task_info_t)&task_info_data,

            &count);

    if (kr != KERN_SUCCESS) {

        // Most likely cause: |task| is a zombie.

        return -1;

    }

    /* Set total_time. */

    // thread info contains live time...

    TIME_VALUE_TO_TIMEVAL(&thread_info_data.user_time, &user_timeval);

    TIME_VALUE_TO_TIMEVAL(&thread_info_data.system_time, &system_timeval);

    timeradd(&user_timeval, &system_timeval, &task_timeval);

    // ... task info contains terminated time.

    TIME_VALUE_TO_TIMEVAL(&task_info_data.user_time, &user_timeval);

    TIME_VALUE_TO_TIMEVAL(&task_info_data.system_time, &system_timeval);

    timeradd(&user_timeval, &task_timeval, &task_timeval);

    timeradd(&system_timeval, &task_timeval, &task_timeval);

    if (gettimeofday(&now, NULL) < 0) {

       return -1;

    }

    jint ncpus      = JVM_ActiveProcessorCount();

    jlong time      = TIME_VALUE_TO_MICROSECONDS(now) * ncpus;

    jlong task_time = TIME_VALUE_TO_MICROSECONDS(task_timeval);

    if ((last_task_time == 0) || (last_time == 0)) {

        // First call, just set the last values.

        last_task_time = task_time;

        last_time      = time;

        // return 0 since we have no data, not -1 which indicates error

        return 0;

    }

    jlong task_time_delta = task_time - last_task_time;

    jlong time_delta      = time - last_time;

    if (time_delta == 0) {

        return -1;

    }

    jdouble cpu = (jdouble) task_time_delta / time_delta;

    last_task_time = task_time;

    last_time      = time;

    return cpu;

 }