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/* g-ring.c
*
* Copyright (C) 2010 Christian Hergert <chris@dronelabs.com>
*
* This file 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 2.1 of the License, or (at your option) any later version.
*
* This file 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 General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <string.h>
#include "g-ring.h"
#ifndef g_malloc0_n
#define g_malloc0_n(x,y) g_malloc0(x * y)
#endif
#define get_element(r,i) ((r)->data + ((r)->elt_size * i))
typedef struct _GRingImpl GRingImpl;
struct _GRingImpl
{
guint8 *data; /* Pointer to real data. */
guint len; /* Length of data allocation. */
guint pos; /* Position in ring. */
guint elt_size; /* Size of each element. */
gboolean looped; /* Have we wrapped around at least once. */
GDestroyNotify destroy; /* Destroy element callback. */
volatile gint ref_count; /* Reference count. */
};
/**
* g_ring_sized_new:
* @element_size: (in): The size per element.
* @reserved_size: (in): The number of elements to allocate.
* @element_destroy: (in): Notification called when removing an element.
*
* Creates a new instance of #GRing with the given number of elements.
*
* Returns: A new #GRing.
* Side effects: None.
*/
GRing*
g_ring_sized_new (guint element_size,
guint reserved_size,
GDestroyNotify element_destroy)
{
GRingImpl *ring_impl;
ring_impl = g_slice_new0(GRingImpl);
ring_impl->elt_size = element_size;
ring_impl->len = reserved_size;
ring_impl->data = g_malloc0_n(reserved_size, element_size);
ring_impl->destroy = element_destroy;
ring_impl->ref_count = 1;
return (GRing *)ring_impl;
}
/**
* g_ring_append_vals:
* @ring: (in): A #GRing.
* @data: (in): A pointer to the array of values.
* @len: (in): The number of values.
*
* Appends @len values located at @data.
*
* Returns: None.
* Side effects: None.
*/
void
g_ring_append_vals (GRing *ring,
gconstpointer data,
guint len)
{
GRingImpl *ring_impl = (GRingImpl *)ring;
gpointer idx;
gint x;
gint i;
g_return_if_fail(ring_impl != NULL);
for (i = 0; i < len; i++) {
x = ring->pos - i;
x = (x >= 0) ? x : ring->len + x;
idx = ring->data + (ring_impl->elt_size * x);
if (ring_impl->destroy && ring_impl->looped == TRUE) {
ring_impl->destroy(idx);
}
memcpy(idx, data, ring_impl->elt_size);
ring->pos++;
if (ring->pos >= ring->len) {
ring_impl->looped = TRUE;
}
ring->pos %= ring->len;
data += ring_impl->elt_size;
}
}
/**
* g_ring_foreach:
* @ring: (in): A #GRing.
* @func: (in): A #GFunc to call for each element.
* @user_data: (in): user data for @func.
*
* Calls @func for every item in the #GRing starting from the most recently
* inserted element to the least recently inserted.
*
* Returns: None.
* Side effects: None.
*/
void
g_ring_foreach (GRing *ring,
GFunc func,
gpointer user_data)
{
GRingImpl *ring_impl = (GRingImpl *)ring;
gint i;
g_return_if_fail(ring_impl != NULL);
g_return_if_fail(func != NULL);
for (i = ring_impl->pos - 1; i >= 0; i--) {
func(get_element(ring_impl, i), user_data);
}
for (i = ring->len - 1; i >= ring_impl->pos; i--) {
func(get_element(ring_impl, i), user_data);
}
}
/**
* g_ring_destroy:
* @ring: (in): A #GRing.
*
* Cleans up after a #GRing that is no longer in use.
*
* Returns: None.
* Side effects: None.
*/
void
g_ring_destroy (GRing *ring)
{
GRingImpl *ring_impl = (GRingImpl *)ring;
g_return_if_fail(ring != NULL);
g_return_if_fail(ring_impl->ref_count == 0);
g_free(ring_impl->data);
g_slice_free(GRingImpl, ring_impl);
}
/**
* g_ring_ref:
* @ring: (in): A #GRing.
*
* Atomically increments the reference count of @ring by one.
*
* Returns: The @ring pointer.
* Side effects: None.
*/
GRing*
g_ring_ref (GRing *ring)
{
GRingImpl *ring_impl = (GRingImpl *)ring;
g_return_val_if_fail(ring != NULL, NULL);
g_return_val_if_fail(ring_impl->ref_count > 0, NULL);
g_atomic_int_inc(&ring_impl->ref_count);
return ring;
}
/**
* g_ring_unref:
* @ring: (in): A #GRing.
*
* Atomically decrements the reference count of @ring by one. When the
* reference count reaches zero, the structure is freed.
*
* Returns: None.
* Side effects: None.
*/
void
g_ring_unref (GRing *ring)
{
GRingImpl *ring_impl = (GRingImpl *)ring;
g_return_if_fail(ring != NULL);
g_return_if_fail(ring_impl->ref_count > 0);
if (g_atomic_int_dec_and_test(&ring_impl->ref_count)) {
g_ring_destroy(ring);
}
}
/**
* g_ring_get_type:
*
* Retrieves the #GType identifier for #GRing.
*
* Returns: The #GType for #GRing.
* Side effects: The type is registered on first call.
*/
GType
g_ring_get_type (void)
{
static gsize initialized = FALSE;
static GType type_id = 0;
if (g_once_init_enter(&initialized)) {
type_id = g_boxed_type_register_static("GRing",
(GBoxedCopyFunc)g_ring_ref,
(GBoxedFreeFunc)g_ring_unref);
g_once_init_leave(&initialized, TRUE);
}
return type_id;
}
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