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/* dzl-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/>.
*/
#define G_LOG_DOMAIN "dzl-ring"
#include "config.h"
#include <string.h>
#include "dzl-ring.h"
#define get_element(r,i) ((r)->data + ((r)->elt_size * i))
typedef struct
{
/*< public >*/
guint8 *data; /* Pointer to real data. */
guint len; /* Length of data allocation. */
guint pos; /* Position in ring. */
/*< private >*/
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; /* Hidden Reference count. */
} DzlRingImpl;
G_DEFINE_BOXED_TYPE (DzlRing, dzl_ring, dzl_ring_ref, dzl_ring_unref)
/**
* dzl_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 #DzlRing with the given number of elements.
*
* Returns: A new #DzlRing.
*/
DzlRing*
dzl_ring_sized_new (guint element_size,
guint reserved_size,
GDestroyNotify element_destroy)
{
DzlRingImpl *ring_impl;
ring_impl = g_slice_new0 (DzlRingImpl);
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 (DzlRing *)ring_impl;
}
/**
* dzl_ring_append_vals:
* @ring: (in): A #DzlRing.
* @data: (in): A pointer to the array of values.
* @len: (in): The number of values.
*
* Appends @len values located at @data.
*
* Returns: the index of the first item.
*/
guint
dzl_ring_append_vals (DzlRing *ring,
gconstpointer data,
guint len)
{
DzlRingImpl *ring_impl = (DzlRingImpl *)ring;
gpointer idx;
gint ret = -1;
gint x;
g_return_val_if_fail (ring_impl != NULL, 0);
g_return_val_if_fail (len <= ring->len, 0);
g_return_val_if_fail (len > 0, 0);
g_return_val_if_fail (len <= G_MAXINT, 0);
for (gint i = 0; i < (gint)len; i++)
{
x = ring->pos - i;
x = (x >= 0) ? x : (gint)ring->len + x;
idx = ring->data + (ring_impl->elt_size * x);
if (ring_impl->destroy && (ring_impl->looped == TRUE))
ring_impl->destroy (idx);
if (ret == -1)
ret = x;
memcpy (idx, data, ring_impl->elt_size);
ring->pos++;
if (ring->pos >= ring->len)
ring_impl->looped = TRUE;
ring->pos %= ring->len;
data = ((guint8 *)data) + ring_impl->elt_size;
}
return (guint)ret;
}
/**
* dzl_ring_foreach:
* @ring: (in): A #DzlRing.
* @func: (in) (scope call): A #GFunc to call for each element.
* @user_data: (in): user data for @func.
*
* Calls @func for every item in the #DzlRing starting from the most recently
* inserted element to the least recently inserted.
*/
void
dzl_ring_foreach (DzlRing *ring,
GFunc func,
gpointer user_data)
{
DzlRingImpl *ring_impl = (DzlRingImpl *)ring;
gint i;
g_return_if_fail (ring_impl != NULL);
g_return_if_fail (func != NULL);
if (!ring_impl->looped)
{
for (i = 0; i < (gint)ring_impl->pos; i++)
func (get_element (ring_impl, i), user_data);
return;
}
for (i = ring_impl->pos; i < (gint)ring_impl->len; i++)
func (get_element (ring_impl, i), user_data);
for (i = 0; i < (gint)ring_impl->pos; i++)
func (get_element (ring_impl, i), user_data);
}
/**
* dzl_ring_destroy:
* @ring: (in): A #DzlRing.
*
* Cleans up after a #DzlRing that is no longer in use.
*/
void
dzl_ring_destroy (DzlRing *ring)
{
DzlRingImpl *ring_impl = (DzlRingImpl *)ring;
g_return_if_fail (ring != NULL);
g_return_if_fail (ring_impl->ref_count == 0);
if (ring_impl->destroy != NULL)
dzl_ring_foreach (ring, (GFunc)ring_impl->destroy, NULL);
g_free (ring_impl->data);
g_slice_free (DzlRingImpl, ring_impl);
}
/**
* dzl_ring_ref:
* @ring: (in): A #DzlRing.
*
* Atomically increments the reference count of @ring by one.
*
* Returns: The @ring pointer.
*/
DzlRing *
dzl_ring_ref (DzlRing *ring)
{
DzlRingImpl *ring_impl = (DzlRingImpl *)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;
}
/**
* dzl_ring_unref:
* @ring: (in): A #DzlRing.
*
* Atomically decrements the reference count of @ring by one. When the
* reference count reaches zero, the structure is freed.
*/
void
dzl_ring_unref (DzlRing *ring)
{
DzlRingImpl *ring_impl = (DzlRingImpl *)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))
dzl_ring_destroy (ring);
}
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