LXR uboot/lib/circbuf.c

   1/*
   2 * (C) Copyright 2003
   3 * Gerry Hamel, geh@ti.com, Texas Instruments
   4 *
   5 * SPDX-License-Identifier:     GPL-2.0+
   6 */
   7
   8#include <common.h>
   9#include <malloc.h>
  10
  11#include <circbuf.h>
  12
  13
  14int buf_init (circbuf_t * buf, unsigned int size)
  15{
  16        assert (buf != NULL);
  17
  18        buf->size = 0;
  19        buf->totalsize = size;
  20        buf->data = (char *) malloc (sizeof (char) * size);
  21        assert (buf->data != NULL);
  22
  23        buf->top = buf->data;
  24        buf->tail = buf->data;
  25        buf->end = &(buf->data[size]);
  26
  27        return 1;
  28}
  29
  30int buf_free (circbuf_t * buf)
  31{
  32        assert (buf != NULL);
  33        assert (buf->data != NULL);
  34
  35        free (buf->data);
  36        memset (buf, 0, sizeof (circbuf_t));
  37
  38        return 1;
  39}
  40
  41int buf_pop (circbuf_t * buf, char *dest, unsigned int len)
  42{
  43        unsigned int i;
  44        char *p = buf->top;
  45
  46        assert (buf != NULL);
  47        assert (dest != NULL);
  48
  49        /* Cap to number of bytes in buffer */
  50        if (len > buf->size)
  51                len = buf->size;
  52
  53        for (i = 0; i < len; i++) {
  54                dest[i] = *p++;
  55                /* Bounds check. */
  56                if (p == buf->end) {
  57                        p = buf->data;
  58                }
  59        }
  60
  61        /* Update 'top' pointer */
  62        buf->top = p;
  63        buf->size -= len;
  64
  65        return len;
  66}
  67
  68int buf_push (circbuf_t * buf, const char *src, unsigned int len)
  69{
  70        /* NOTE:  this function allows push to overwrite old data. */
  71        unsigned int i;
  72        char *p = buf->tail;
  73
  74        assert (buf != NULL);
  75        assert (src != NULL);
  76
  77        for (i = 0; i < len; i++) {
  78                *p++ = src[i];
  79                if (p == buf->end) {
  80                        p = buf->data;
  81                }
  82                /* Make sure pushing too much data just replaces old data */
  83                if (buf->size < buf->totalsize) {
  84                        buf->size++;
  85                } else {
  86                        buf->top++;
  87                        if (buf->top == buf->end) {
  88                                buf->top = buf->data;
  89                        }
  90                }
  91        }
  92
  93        /* Update 'tail' pointer */
  94        buf->tail = p;
  95
  96        return len;
  97}
  98