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/*************************************************************************
* Copyright (C) 2009-2010 Tavian Barnes <tavianator@gmail.com> *
* *
* This file is part of The Dimension Library. *
* *
* The Dimension 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 Dimension 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 "dimension-impl.h"
#include <pthread.h>
/* A single element in an array for dmnsn_progress. Progress of this item is
progress/total. */
typedef struct {
unsigned int progress, total;
} dmnsn_progress_element;
/* For thread synchronization */
static void dmnsn_progress_rdlock(const dmnsn_progress *progress);
static void dmnsn_progress_wrlock(dmnsn_progress *progress);
static void dmnsn_progress_unlock(const dmnsn_progress *progress);
/* Allocate a new dmnsn_progress* */
dmnsn_progress *
dmnsn_new_progress()
{
dmnsn_progress *progress = dmnsn_malloc(sizeof(dmnsn_progress));
progress->elements = dmnsn_new_array(sizeof(dmnsn_progress_element));
dmnsn_progress_element element = { .progress = 0, .total = 1 };
dmnsn_array_push(progress->elements, &element);
/* Initialize the rwlock, condition variable, and mutex */
progress->rwlock = dmnsn_malloc(sizeof(pthread_rwlock_t));
if (pthread_rwlock_init(progress->rwlock, NULL) != 0) {
dmnsn_error(DMNSN_SEVERITY_HIGH, "Couldn't initialize read-write lock.");
}
progress->cond = dmnsn_malloc(sizeof(pthread_cond_t));
if (pthread_cond_init(progress->cond, NULL) != 0) {
dmnsn_error(DMNSN_SEVERITY_HIGH, "Couldn't initialize condition variable.");
}
progress->mutex = dmnsn_malloc(sizeof(pthread_mutex_t));
if (pthread_mutex_init(progress->mutex, NULL) != 0) {
dmnsn_error(DMNSN_SEVERITY_HIGH, "Couldn't initialize mutex.");
}
progress->min_wait = 1.0;
progress->min_waitp = &progress->min_wait;
return progress;
}
/* Join the worker thread and delete `progress'. */
int
dmnsn_finish_progress(dmnsn_progress *progress)
{
void *ptr;
int retval = -1;
if (progress) {
/* Get the thread's return value */
if (pthread_join(progress->thread, &ptr) != 0) {
/* Medium severity because an unjoined thread likely means that the thread
is incomplete or invalid */
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Joining worker thread failed.");
} else if (ptr) {
retval = *(int *)ptr;
dmnsn_free(ptr);
}
/* Free the progress object */
if (pthread_rwlock_destroy(progress->rwlock) != 0) {
dmnsn_error(DMNSN_SEVERITY_LOW, "Leaking rwlock.");
}
if (pthread_mutex_destroy(progress->mutex) != 0) {
dmnsn_error(DMNSN_SEVERITY_LOW, "Leaking mutex.");
}
if (pthread_cond_destroy(progress->cond) != 0) {
dmnsn_error(DMNSN_SEVERITY_LOW, "Leaking condition variable.");
}
dmnsn_free(progress->rwlock);
dmnsn_free(progress->mutex);
dmnsn_free(progress->cond);
dmnsn_delete_array(progress->elements);
dmnsn_free(progress);
}
return retval;
}
/* Get the current progress of the worker thread, in [0.0, 1.0] */
double
dmnsn_get_progress(const dmnsn_progress *progress)
{
dmnsn_progress_element *element;
double prog = 0.0;
dmnsn_progress_rdlock(progress);
size_t size = dmnsn_array_size(progress->elements);
for (size_t i = 0; i < size; ++i) {
element = dmnsn_array_at(progress->elements, size - i - 1);
prog += element->progress;
prog /= element->total;
}
dmnsn_progress_unlock(progress);
return prog;
}
/* Wait until dmnsn_get_progress(progress) >= prog */
void
dmnsn_wait_progress(const dmnsn_progress *progress, double prog)
{
if (pthread_mutex_lock(progress->mutex) != 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't lock condition mutex.");
/* Busy-wait if we can't use the condition variable */
while (dmnsn_get_progress(progress) < prog);
} else {
while (dmnsn_get_progress(progress) < prog) {
/* Set the minimum waited-on value */
if (prog < progress->min_wait)
*progress->min_waitp = prog;
if (pthread_cond_wait(progress->cond, progress->mutex) != 0) {
dmnsn_error(DMNSN_SEVERITY_LOW,
"Couldn't wait on condition variable.");
}
}
if (pthread_mutex_unlock(progress->mutex) != 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't unlock condition mutex.");
}
}
}
/* Start a new level of algorithmic nesting */
void
dmnsn_new_progress_element(dmnsn_progress *progress, unsigned int total)
{
dmnsn_progress_element element = { .progress = 0, .total = total };
dmnsn_progress_wrlock(progress);
dmnsn_array_push(progress->elements, &element);
dmnsn_progress_unlock(progress);
}
/* Only the innermost loop needs to call this function - it handles the rest
upon loop completion (progress == total) */
void
dmnsn_increment_progress(dmnsn_progress *progress)
{
dmnsn_progress_element *element;
dmnsn_progress_wrlock(progress);
size_t size = dmnsn_array_size(progress->elements);
element = dmnsn_array_at(progress->elements, size - 1);
++element->progress; /* Increment the last element */
while (element->progress >= element->total && size > 1) {
/* As long as the last element is complete, pop it */
--size;
dmnsn_array_resize(progress->elements, size);
element = dmnsn_array_at(progress->elements, size - 1);
++element->progress; /* Increment the next element */
}
dmnsn_progress_unlock(progress);
if (pthread_mutex_lock(progress->mutex) != 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't lock condition mutex.");
}
if (dmnsn_get_progress(progress) >= progress->min_wait) {
progress->min_wait = 1.0;
if (pthread_cond_broadcast(progress->cond) != 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't signal condition variable.");
}
}
if (pthread_mutex_unlock(progress->mutex) != 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't unlock condition mutex.");
}
}
/* Immediately set to 100% completion */
void
dmnsn_done_progress(dmnsn_progress *progress)
{
dmnsn_progress_element *element;
dmnsn_progress_wrlock(progress);
dmnsn_array_resize(progress->elements, 1);
element = dmnsn_array_at(progress->elements, 0);
element->progress = element->total;
dmnsn_progress_unlock(progress);
if (pthread_mutex_lock(progress->mutex) != 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't lock condition mutex.");
}
if (pthread_cond_broadcast(progress->cond) != 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't signal condition variable.");
}
if (pthread_mutex_unlock(progress->mutex) != 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't unlock condition mutex.");
}
}
/* Thread synchronization */
static void
dmnsn_progress_rdlock(const dmnsn_progress *progress)
{
if (pthread_rwlock_rdlock(progress->rwlock) != 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't acquire read-lock.");
}
}
static void
dmnsn_progress_wrlock(dmnsn_progress *progress)
{
if (pthread_rwlock_wrlock(progress->rwlock) != 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't acquire write-lock.");
}
}
static void
dmnsn_progress_unlock(const dmnsn_progress *progress)
{
if (pthread_rwlock_unlock(progress->rwlock) != 0) {
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't unlock read-write lock.");
}
}
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