circbuf: Move to lib_generic and conditionally compile

circbuf could be used as a generic library and is only currently
needed when CONFIG_USB_TTY is defined.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>

1 files changed, 110 insertions, 0 deletions

diff --git a/lib_generic/circbuf.c b/lib_generic/circbuf.c
new file mode 100644
index 0000000..2332c63
--- /dev/null
+++ b/lib_generic/circbuf.c
@@ -0,0 +1,110 @@
+/*
+ * (C) Copyright 2003
+ * Gerry Hamel, geh@ti.com, Texas Instruments
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307	 USA
+ *
+ */
+
+#include <common.h>
+#include <malloc.h>
+
+#include <circbuf.h>
+
+
+int buf_init (circbuf_t * buf, unsigned int size)
+{
+	assert (buf != NULL);
+
+	buf->size = 0;
+	buf->totalsize = size;
+	buf->data = (char *) malloc (sizeof (char) * size);
+	assert (buf->data != NULL);
+
+	buf->top = buf->data;
+	buf->tail = buf->data;
+	buf->end = &(buf->data[size]);
+
+	return 1;
+}
+
+int buf_free (circbuf_t * buf)
+{
+	assert (buf != NULL);
+	assert (buf->data != NULL);
+
+	free (buf->data);
+	memset (buf, 0, sizeof (circbuf_t));
+
+	return 1;
+}
+
+int buf_pop (circbuf_t * buf, char *dest, unsigned int len)
+{
+	unsigned int i;
+	char *p = buf->top;
+
+	assert (buf != NULL);
+	assert (dest != NULL);
+
+	/* Cap to number of bytes in buffer */
+	if (len > buf->size)
+		len = buf->size;
+
+	for (i = 0; i < len; i++) {
+		dest[i] = *p++;
+		/* Bounds check. */
+		if (p == buf->end) {
+			p = buf->data;
+		}
+	}
+
+	/* Update 'top' pointer */
+	buf->top = p;
+	buf->size -= len;
+
+	return len;
+}
+
+int buf_push (circbuf_t * buf, const char *src, unsigned int len)
+{
+	/* NOTE:  this function allows push to overwrite old data. */
+	unsigned int i;
+	char *p = buf->tail;
+
+	assert (buf != NULL);
+	assert (src != NULL);
+
+	for (i = 0; i < len; i++) {
+		*p++ = src[i];
+		if (p == buf->end) {
+			p = buf->data;
+		}
+		/* Make sure pushing too much data just replaces old data */
+		if (buf->size < buf->totalsize) {
+			buf->size++;
+		} else {
+			buf->top++;
+			if (buf->top == buf->end) {
+				buf->top = buf->data;
+			}
+		}
+	}
+
+	/* Update 'tail' pointer */
+	buf->tail = p;
+
+	return len;
+}