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
  14 int 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
  30 int 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
  41 int 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
  68 int 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 }