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-rw-r--r--lib/circbuf.c110
1 files changed, 110 insertions, 0 deletions
diff --git a/lib/circbuf.c b/lib/circbuf.c
new file mode 100644
index 00000000000..2332c63717d
--- /dev/null
+++ b/lib/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;
+}