full directory structure

main/buffer.c

@@ -0,0 +1,115 @@
+/* 
+ *  Squeezelite - lightweight headless squeezebox emulator
+ *
+ *  (c) Adrian Smith 2012-2015, triode1@btinternet.com
+ *      Ralph Irving 2015-2017, ralph_irving@hotmail.com
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+// fifo bufffers 
+
+#define _GNU_SOURCE
+
+#include "squeezelite.h"
+
+// _* called with muxtex locked
+
+inline unsigned _buf_used(struct buffer *buf) {
+	return buf->writep >= buf->readp ? buf->writep - buf->readp : buf->size - (buf->readp - buf->writep);
+}
+
+unsigned _buf_space(struct buffer *buf) {
+	return buf->size - _buf_used(buf) - 1; // reduce by one as full same as empty otherwise
+}
+
+unsigned _buf_cont_read(struct buffer *buf) {
+	return buf->writep >= buf->readp ? buf->writep - buf->readp : buf->wrap - buf->readp;
+}
+
+unsigned _buf_cont_write(struct buffer *buf) {
+	return buf->writep >= buf->readp ? buf->wrap - buf->writep : buf->readp - buf->writep;
+}
+
+void _buf_inc_readp(struct buffer *buf, unsigned by) {
+	buf->readp += by;
+	if (buf->readp >= buf->wrap) {
+		buf->readp -= buf->size;
+	}
+}
+
+void _buf_inc_writep(struct buffer *buf, unsigned by) {
+	buf->writep += by;
+	if (buf->writep >= buf->wrap) {
+		buf->writep -= buf->size;
+	}
+}
+
+void buf_flush(struct buffer *buf) {
+	mutex_lock(buf->mutex);
+	buf->readp  = buf->buf;
+	buf->writep = buf->buf;
+	mutex_unlock(buf->mutex);
+}
+
+// adjust buffer to multiple of mod bytes so reading in multiple always wraps on frame boundary
+void buf_adjust(struct buffer *buf, size_t mod) {
+	size_t size;
+	mutex_lock(buf->mutex);
+	size = ((unsigned)(buf->base_size / mod)) * mod;
+	buf->readp  = buf->buf;
+	buf->writep = buf->buf;
+	buf->wrap   = buf->buf + size;
+	buf->size   = size;
+	mutex_unlock(buf->mutex);
+}
+
+// called with mutex locked to resize, does not retain contents, reverts to original size if fails
+void _buf_resize(struct buffer *buf, size_t size) {
+	free(buf->buf);
+	buf->buf = malloc(size);
+	if (!buf->buf) {
+		size    = buf->size;
+		buf->buf= malloc(size);
+		if (!buf->buf) {
+			size = 0;
+		}
+	}
+	buf->readp  = buf->buf;
+	buf->writep = buf->buf;
+	buf->wrap   = buf->buf + size;
+	buf->size   = size;
+	buf->base_size = size;
+}
+
+void buf_init(struct buffer *buf, size_t size) {
+	buf->buf    = malloc(size);
+	buf->readp  = buf->buf;
+	buf->writep = buf->buf;
+	buf->wrap   = buf->buf + size;
+	buf->size   = size;
+	buf->base_size = size;
+	mutex_create_p(buf->mutex);
+}
+
+void buf_destroy(struct buffer *buf) {
+	if (buf->buf) {
+		free(buf->buf);
+		buf->buf = NULL;
+		buf->size = 0;
+		buf->base_size = 0;
+		mutex_destroy(buf->mutex);
+	}
+}