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/*************************************************************************
* Copyright (C) 2008 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.h"
#include <pthread.h>
#include <string.h> /* For memcpy */
/* The raw implementations, which don't do any thread synchronicity */
static void dmnsn_array_get_impl(const dmnsn_array *array, size_t i, void *obj);
static void dmnsn_array_set_impl(dmnsn_array *array, size_t i, const void *obj);
/* Allocate a new array - guaranteed not to fail if it returns */
dmnsn_array *
dmnsn_new_array(size_t obj_size)
{
dmnsn_array *array = malloc(sizeof(dmnsn_array));
if (array) {
array->obj_size = obj_size;
array->length = 0;
array->capacity = 4; /* Start with capacity of 4 */
/* Allocate the memory */
array->ptr = malloc(array->capacity*array->obj_size);
if (!array->ptr) {
dmnsn_error(DMNSN_SEVERITY_HIGH, "Array allocation failed.");
}
/* Allocate the read-write lock */
array->rwlock = malloc(sizeof(pthread_rwlock_t));
if (!array->rwlock || pthread_rwlock_init(array->rwlock, NULL) != 0) {
dmnsn_error(DMNSN_SEVERITY_HIGH, "Array rwlock allocation failed.");
}
}
return array;
}
/* Delete the array */
void dmnsn_delete_array(dmnsn_array *array) {
if (array) {
if (pthread_rwlock_destroy(array->rwlock) != 0) {
dmnsn_error(DMNSN_SEVERITY_LOW, "Leaking rwlock in array deallocation.");
}
free(array->rwlock);
free(array->ptr);
free(array);
}
}
/* Push obj to the end of the array, atomically */
void
dmnsn_array_push(dmnsn_array *array, const void *obj)
{
dmnsn_array_wrlock(array);
dmnsn_array_set_impl(array, dmnsn_array_size_unlocked(array), obj);
dmnsn_array_unlock(array);
}
/* Pop obj from the end of the array, atomically */
void
dmnsn_array_pop(dmnsn_array *array, void *obj)
{
size_t size;
dmnsn_array_wrlock(array);
size = dmnsn_array_size_unlocked(array);
dmnsn_array_get_impl(array, size - 1, obj); /* Copy the object */
dmnsn_array_resize_unlocked(array, size - 1); /* Shrink the array */
dmnsn_array_unlock(array);
}
/* Get the i'th object, bailing out if i is out of range */
void
dmnsn_array_get(const dmnsn_array *array, size_t i, void *obj)
{
dmnsn_array_rdlock(array);
dmnsn_array_get_impl(array, i, obj);
dmnsn_array_unlock(array);
}
/* Set the i'th object, expanding the array if necessary */
void
dmnsn_array_set(dmnsn_array *array, size_t i, const void *obj)
{
dmnsn_array_wrlock(array);
dmnsn_array_set_impl(array, i, obj);
dmnsn_array_unlock(array);
}
/* Get the size of the array, atomically */
size_t
dmnsn_array_size(const dmnsn_array *array)
{
size_t size;
dmnsn_array_rdlock(array);
size = dmnsn_array_size_unlocked(array);
dmnsn_array_unlock(array);
return size;
}
/* Set the size of the array, atomically */
void
dmnsn_array_resize(dmnsn_array *array, size_t length)
{
dmnsn_array_wrlock(array);
dmnsn_array_resize_unlocked(array, length);
dmnsn_array_unlock(array);
}
/* Thread-unsafe range-checked element access */
void *
dmnsn_array_at(dmnsn_array *array, size_t i)
{
if (i >= dmnsn_array_size_unlocked(array)) {
dmnsn_error(DMNSN_SEVERITY_HIGH, "Array index out of bounds.");
}
return (char *)array->ptr + array->obj_size*i;
}
/* Get the size non-atomically, for manual locking */
size_t
dmnsn_array_size_unlocked(const dmnsn_array *array)
{
return array->length;
}
/* Set the size non-atomically, for manual locking */
void
dmnsn_array_resize_unlocked(dmnsn_array *array, size_t length)
{
if (length > array->capacity) {
/* Resize if we don't have enough capacity */
array->capacity = length*2; /* We are greedy */
array->ptr = realloc(array->ptr, array->obj_size*array->capacity);
if (!array->ptr) {
dmnsn_error(DMNSN_SEVERITY_HIGH, "Resizing array failed.");
}
}
array->length = length;
}
/* Set a manual read-lock */
void
dmnsn_array_rdlock(const dmnsn_array *array)
{
if (pthread_rwlock_rdlock(array->rwlock) != 0) {
/* Medium severity, because undefined behaviour is pretty likely if our
reads and writes aren't synced */
dmnsn_error(DMNSN_SEVERITY_MEDIUM,
"Couldn't acquire read-lock for array.");
}
}
/* Set a manual write-lock */
void
dmnsn_array_wrlock(dmnsn_array *array)
{
if (pthread_rwlock_wrlock(array->rwlock) != 0) {
/* Medium severity, because undefined behaviour is pretty likely if our
reads and writes aren't synced */
dmnsn_error(DMNSN_SEVERITY_MEDIUM,
"Couldn't acquire write-lock for array.");
}
}
/* Unset a manual lock */
void
dmnsn_array_unlock(const dmnsn_array *array)
{
if (pthread_rwlock_unlock(array->rwlock) != 0) {
/* Medium severity, because if the array is locked, we're likely to hang
the next time we try to read or write it */
dmnsn_error(DMNSN_SEVERITY_MEDIUM, "Couldn't unlock array.");
}
}
/* Actual "get" implementation */
static void
dmnsn_array_get_impl(const dmnsn_array *array, size_t i, void *obj)
{
if (i >= dmnsn_array_size_unlocked(array)) {
/* Range check failed */
dmnsn_error(DMNSN_SEVERITY_HIGH, "Array index out of bounds.");
}
memcpy(obj, array->ptr + array->obj_size*i, array->obj_size);
}
/* Actual "set" implementation */
static void
dmnsn_array_set_impl(dmnsn_array *array, size_t i, const void *obj)
{
if (i >= dmnsn_array_size_unlocked(array)) {
/* Resize if i is out of range */
dmnsn_array_resize_unlocked(array, i + 1);
}
memcpy(array->ptr + array->obj_size*i, obj, array->obj_size);
}
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