From ab48b5d2be4a3c576205aa25e8332ff102db8378 Mon Sep 17 00:00:00 2001
From: Thomas White <taw@bitwiz.org.uk>
Date: Wed, 15 Feb 2012 00:36:32 +0100
Subject: Make stuff work

---
 fifo.c | 99 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)
 create mode 100644 fifo.c

(limited to 'fifo.c')

diff --git a/fifo.c b/fifo.c
new file mode 100644
index 0000000..245fb8e
--- /dev/null
+++ b/fifo.c
@@ -0,0 +1,99 @@
+/*
+ * fifo.c
+ *
+ * (c) 2012 Thomas White <taw@bitwiz.org.uk>
+ *
+ * This file is part of MIDInator.
+ *
+ * MIDInator 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.
+ *
+ * MIDInator 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 MIDInator.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <stdlib.h>
+#include <pthread.h>
+
+#include "fifo.h"
+
+struct _fifo
+{
+	pthread_mutex_t lock;
+
+	unsigned char *buf;
+	size_t sz;
+	size_t n_used;
+
+	size_t r;  /* Read pointer */
+	size_t w;  /* Write pointer */
+};
+
+
+FIFO *fifo_new()
+{
+	FIFO *f;
+
+	f = malloc(sizeof(struct _fifo));
+	if ( f == NULL ) return NULL;
+
+	f->sz = 64*1024;
+	f->buf = malloc(f->sz);
+	if ( f->buf == NULL ) {
+		free(f);
+		return NULL;
+	}
+
+	f->r = 0;
+	f->w = 0;
+	f->n_used = 0;
+
+	pthread_mutex_init(&f->lock, NULL);
+
+	return f;
+}
+
+
+void fifo_push(FIFO *f, unsigned char c)
+{
+	pthread_mutex_lock(&f->lock);
+
+	f->buf[f->w++] = c;
+	f->n_used++;
+
+	if ( f->w == f->sz ) {
+		f->w = 0;
+	}
+
+	pthread_mutex_unlock(&f->lock);
+}
+
+
+unsigned char fifo_pop(FIFO *f, int *err)
+{
+	unsigned char c;
+
+	pthread_mutex_lock(&f->lock);
+
+	if ( f->n_used == 0 ) {
+		pthread_mutex_unlock(&f->lock);
+		*err = 1;
+		return 0;
+	}
+
+	*err = 0;
+	c = f->buf[f->r++];
+	f->n_used--;
+
+	pthread_mutex_unlock(&f->lock);
+
+	return c;
+}
-- 
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