circbuf.c
2.26 KB
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/*
* (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;
}