libs: New growing-only queue.

This is a queue which has the same API as GQueue, except that:
* It uses an array, instead of a doubled-linked-list
* The array can only grow.

This code is not-threadsafe. It is up to the owner to make sure the
proper locking is taken before calling this API.

libs/gst/base/Makefile.am

@@ -13,7 +13,8 @@ libgstbase_@GST_API_VERSION@_la_SOURCES = \
 	gstbytewriter.c         \
 	gstcollectpads.c	\
 	gstpushsrc.c		\
-	gsttypefindhelper.c
+	gsttypefindhelper.c	\
+	gstqueuearray.c
 
 libgstbase_@GST_API_VERSION@_la_CFLAGS = $(GST_OBJ_CFLAGS)
 libgstbase_@GST_API_VERSION@_la_LIBADD = $(GST_OBJ_LIBS)
@@ -33,7 +34,8 @@ libgstbase_@GST_API_VERSION@include_HEADERS =	\
 	gstbytewriter.h         \
 	gstcollectpads.h	\
 	gstpushsrc.h		\
-	gsttypefindhelper.h
+	gsttypefindhelper.h	\
+	gstqueuearray.h
 
 noinst_HEADERS = \
 	gstbytereader-docs.h \

libs/gst/base/gstqueuearray.c

@@ -0,0 +1,162 @@
+/* GStreamer
+ * Copyright (C) 2009 Edward Hervey <bilboed@bilboed.com>
+ *
+ * gstqueuearray.c:
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <string.h>
+#include <gst/gst.h>
+#include "gstqueuearray.h"
+
+GstQueueArray *
+gst_queue_array_new (guint initial_size)
+{
+  GstQueueArray *array = g_malloc (sizeof (GstQueueArray));
+
+  array->size = initial_size;
+  array->array = g_new0 (gpointer, initial_size);
+  array->head = 0;
+  array->tail = 0;
+  array->length = 0;
+
+  return array;
+}
+
+gpointer
+gst_queue_array_pop_head (GstQueueArray * array)
+{
+  gpointer ret;
+
+  /* empty array */
+  if (G_UNLIKELY (array->length == 0))
+    return NULL;
+  ret = array->array[array->head];
+  array->head++;
+  array->head %= array->size;
+  array->length--;
+  return ret;
+}
+
+void
+gst_queue_array_push_tail (GstQueueArray * array, gpointer data)
+{
+  /* Check if we need to make room */
+  if (G_UNLIKELY (array->length == array->size)) {
+    /* newsize is 50% bigger */
+    guint newsize = (3 * array->size) / 2;
+
+    /* copy over data */
+    if (array->tail != 0) {
+      gpointer *array2 = g_new0 (gpointer, newsize);
+      guint t1 = array->head;
+      guint t2 = array->size - array->head;
+
+      /* [0-----TAIL][HEAD------SIZE]
+       *
+       * We want to end up with
+       * [HEAD------------------TAIL][----FREEDATA------NEWSIZE]
+       *
+       * 1) move [HEAD-----SIZE] part to beginning of new array
+       * 2) move [0-------TAIL] part new array, after previous part
+       */
+
+      memcpy (array2, &array->array[array->head], t2 * sizeof (gpointer));
+      memcpy (&array2[t2], array->array, t1 * sizeof (gpointer));
+
+      g_free (array->array);
+      array->array = array2;
+      array->head = 0;
+    } else {
+      /* Fast path, we just need to grow the array */
+      array->array = g_renew (gpointer, array->array, newsize);
+    }
+    array->tail = array->size;
+    array->size = newsize;
+  }
+
+  array->array[array->tail] = data;
+  array->tail++;
+  array->tail %= array->size;
+  array->length++;
+}
+
+gboolean
+gst_queue_array_is_empty (GstQueueArray * array)
+{
+  return (array->length == 0);
+}
+
+void
+gst_queue_array_free (GstQueueArray * array)
+{
+  g_free (array->array);
+  g_free (array);
+}
+
+void
+gst_queue_array_drop_element (GstQueueArray * array, guint idx)
+{
+  if (idx == array->head) {
+    /* just move the head */
+    array->head++;
+    array->head %= array->size;
+    return;
+  }
+  if (idx == array->tail - 1) {
+    /* just move the tail */
+    array->tail = (array->tail - 1 + array->size) % array->size;
+    return;
+  }
+  /* drop the element #idx... and readjust the array */
+  if (array->head < array->tail) {
+    /* Make sure it's within the boundaries */
+    g_assert (array->head < idx && idx <= array->tail);
+    /* ends not wrapped */
+    /* move head-idx to head+1 */
+    memcpy (&array->array[array->head + 1],
+        &array->array[array->head], (idx - array->head) * sizeof (gpointer));
+    array->tail--;
+  } else {
+    /* ends are wrapped */
+    if (idx < array->tail) {
+      /* move idx-tail backwards one */
+      memcpy (&array->array[idx - 1],
+          &array->array[idx], (array->tail - idx) * sizeof (gpointer));
+      array->tail--;
+    } else if (idx >= array->head) {
+      /* move head-idx forwards one */
+      memcpy (&array->array[array->head],
+          &array->array[array->head + 1],
+          (idx - array->head) * sizeof (gpointer));
+      array->head++;
+    } else
+      g_assert_not_reached ();
+  }
+}
+
+guint
+gst_queue_array_find (GstQueueArray * array, GCompareFunc func, gpointer data)
+{
+  guint i;
+
+  /* Scan from head to tail */
+  for (i = array->head; i < array->length; i = (i + 1) % array->size)
+    if (func (array->array[i], data) == 0)
+      return i;
+  return -1;
+}

libs/gst/base/gstqueuearray.h

@@ -0,0 +1,48 @@
+/* GStreamer
+ * Copyright (C) 2009-2010 Edward Hervey <bilboed@bilboed.com>
+ *
+ * gstqueuearray.h:
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <glib.h>
+
+#ifndef __GST_QUEUE_ARRAY_H__
+#define __GST_QUEUE_ARRAY_H__
+
+typedef struct _GstQueueArray GstQueueArray;
+
+struct _GstQueueArray
+{
+  gpointer *array;
+  guint size;
+  guint head;
+  guint tail;
+  guint length;
+};
+
+GstQueueArray *gst_queue_array_new (guint initial_size);
+gpointer gst_queue_array_pop_head (GstQueueArray * array);
+void gst_queue_array_push_tail (GstQueueArray * array, gpointer data);
+gboolean gst_queue_array_is_empty (GstQueueArray * array);
+void gst_queue_array_free (GstQueueArray * array);
+
+void gst_queue_array_drop_element (GstQueueArray * array, guint idx);
+guint gst_queue_array_find (GstQueueArray * array, GCompareFunc func,
+    gpointer data);
+
+#endif

win32/common/libgstbase.def

@@ -237,6 +237,11 @@ EXPORTS
 	gst_collect_pads_stop
 	gst_collect_pads_take_buffer
 	gst_push_src_get_type
+	gst_queue_array_free
+	gst_queue_array_is_empty
+	gst_queue_array_new
+	gst_queue_array_pop_head
+	gst_queue_array_push_tail
 	gst_type_find_helper
 	gst_type_find_helper_for_buffer
 	gst_type_find_helper_for_data