buffer, pipe: convert to C++

src/MusicBuffer.cxx

@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2003-2013 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "config.h"
+#include "MusicBuffer.hxx"
+#include "MusicChunk.hxx"
+#include "poison.h"
+
+#include <glib.h>
+
+#include <assert.h>
+
+struct music_buffer {
+	struct music_chunk *chunks;
+	unsigned num_chunks;
+
+	struct music_chunk *available;
+
+	/** a mutex which protects #available */
+	GMutex *mutex;
+
+#ifndef NDEBUG
+	unsigned num_allocated;
+#endif
+};
+
+struct music_buffer *
+music_buffer_new(unsigned num_chunks)
+{
+	struct music_buffer *buffer;
+	struct music_chunk *chunk;
+
+	assert(num_chunks > 0);
+
+	buffer = g_new(struct music_buffer, 1);
+
+	buffer->chunks = g_new(struct music_chunk, num_chunks);
+	buffer->num_chunks = num_chunks;
+
+	chunk = buffer->available = buffer->chunks;
+	poison_undefined(chunk, sizeof(*chunk));
+
+	for (unsigned i = 1; i < num_chunks; ++i) {
+		chunk->next = &buffer->chunks[i];
+		chunk = chunk->next;
+		poison_undefined(chunk, sizeof(*chunk));
+	}
+
+	chunk->next = NULL;
+
+	buffer->mutex = g_mutex_new();
+
+#ifndef NDEBUG
+	buffer->num_allocated = 0;
+#endif
+
+	return buffer;
+}
+
+void
+music_buffer_free(struct music_buffer *buffer)
+{
+	assert(buffer->chunks != NULL);
+	assert(buffer->num_chunks > 0);
+	assert(buffer->num_allocated == 0);
+
+	g_mutex_free(buffer->mutex);
+	g_free(buffer->chunks);
+	g_free(buffer);
+}
+
+unsigned
+music_buffer_size(const struct music_buffer *buffer)
+{
+	return buffer->num_chunks;
+}
+
+struct music_chunk *
+music_buffer_allocate(struct music_buffer *buffer)
+{
+	struct music_chunk *chunk;
+
+	g_mutex_lock(buffer->mutex);
+
+	chunk = buffer->available;
+	if (chunk != NULL) {
+		buffer->available = chunk->next;
+		music_chunk_init(chunk);
+
+#ifndef NDEBUG
+		++buffer->num_allocated;
+#endif
+	}
+
+	g_mutex_unlock(buffer->mutex);
+	return chunk;
+}
+
+void
+music_buffer_return(struct music_buffer *buffer, struct music_chunk *chunk)
+{
+	assert(buffer != NULL);
+	assert(chunk != NULL);
+
+	if (chunk->other != NULL)
+		music_buffer_return(buffer, chunk->other);
+
+	g_mutex_lock(buffer->mutex);
+
+	music_chunk_free(chunk);
+	poison_undefined(chunk, sizeof(*chunk));
+
+	chunk->next = buffer->available;
+	buffer->available = chunk;
+
+#ifndef NDEBUG
+	--buffer->num_allocated;
+#endif
+
+	g_mutex_unlock(buffer->mutex);
+}