lib/circbuf.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * (C) Copyright 2003
   4  * Gerry Hamel, geh@ti.com, Texas Instruments
   5  */
   6
   7 #include <common.h>
   8 #include <malloc.h>
   9
  10 #include <circbuf.h>
  11
  12
  13 int buf_init (circbuf_t * buf, unsigned int size)
  14 {
  15         assert (buf != NULL);
  16
  17         buf->size = 0;
  18         buf->totalsize = size;
  19         buf->data = (char *) malloc (sizeof (char) * size);
  20         assert (buf->data != NULL);
  21
  22         buf->top = buf->data;
  23         buf->tail = buf->data;
  24         buf->end = &(buf->data[size]);
  25
  26         return 1;
  27 }
  28
  29 int buf_free (circbuf_t * buf)
  30 {
  31         assert (buf != NULL);
  32         assert (buf->data != NULL);
  33
  34         free (buf->data);
  35         memset (buf, 0, sizeof (circbuf_t));
  36
  37         return 1;
  38 }
  39
  40 int buf_pop (circbuf_t * buf, char *dest, unsigned int len)
  41 {
  42         unsigned int i;
  43         char *p;
  44
  45         assert (buf != NULL);
  46         assert (dest != NULL);
  47
  48         p = buf->top;
  49
  50         /* Cap to number of bytes in buffer */
  51         if (len > buf->size)
  52                 len = buf->size;
  53
  54         for (i = 0; i < len; i++) {
  55                 dest[i] = *p++;
  56                 /* Bounds check. */
  57                 if (p == buf->end) {
  58                         p = buf->data;
  59                 }
  60         }
  61
  62         /* Update 'top' pointer */
  63         buf->top = p;
  64         buf->size -= len;
  65
  66         return len;
  67 }
  68
  69 int buf_push (circbuf_t * buf, const char *src, unsigned int len)
  70 {
  71         /* NOTE:  this function allows push to overwrite old data. */
  72         unsigned int i;
  73         char *p;
  74
  75         assert (buf != NULL);
  76         assert (src != NULL);
  77
  78         p = buf->tail;
  79
  80         for (i = 0; i < len; i++) {
  81                 *p++ = src[i];
  82                 if (p == buf->end) {
  83                         p = buf->data;
  84                 }
  85                 /* Make sure pushing too much data just replaces old data */
  86                 if (buf->size < buf->totalsize) {
  87                         buf->size++;
  88                 } else {
  89                         buf->top++;
  90                         if (buf->top == buf->end) {
  91                                 buf->top = buf->data;
  92                         }
  93                 }
  94         }
  95
  96         /* Update 'tail' pointer */
  97         buf->tail = p;
  98
  99         return len;
 100 }