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#include <stdlib.h>
#include <string.h>
#include "rb.h"
#define MAX(_x1, _x2) (((_x1) > (_x2)) ? (_x1) : (_x2))
#define MIN(_x1, _x2) (((_x1) < (_x2)) ? (_x1) : (_x2))
int rb_init(rb_t *rb)
{
rb->off_r = 0;
rb->off_w = 0;
rb->size_filled = 0;
return 0;
}
rb_t *rb_new(void)
{
rb_t *rb;
if ((rb = malloc(sizeof(rb_t))) == NULL) {
return NULL;
}
rb_init(rb);
return rb;
}
void rb_delete(rb_t **rb)
{
free(*rb);
*rb = NULL;
}
rb_t *rb_put(rb_t *rb, const void *src, size_t n)
{
size_t size;
size = rb_get_size(rb);
if (n >= size) {
/* we will override the whole ring buffer */
/* the first bytes of src will not be copied, anyway */
src += (n - size);
memcpy(rb->buffer, src , size);
/* hardcode the values */
rb->size_filled = size;
rb->off_w = 0;
rb->off_r = 0;
return rb;
}
/* loop until n bytes of src have been written */
while (n != 0) {
size = MIN(n, rb_get_size(rb) - rb->off_w);
memcpy(&rb->buffer[rb->off_w], src, size);
/* if we overrided the data to read, we need to move off_r */
if (rb->off_w < rb->off_r && rb->off_w + size > rb->off_r) {
rb->off_r = (rb->off_w + size) % rb_get_size(rb);
} else if (rb->off_r == rb->off_w
&& rb->size_filled == rb_get_size(rb))
{
rb->off_r = (rb->off_w + size) % rb_get_size(rb);
}
/* this will put the offset back to 0 if we reached the end */
rb->off_w = (rb->off_w + size) % rb_get_size(rb);
n -= size;
src += size;
rb->size_filled += size;
rb->size_filled = MIN(rb->size_filled, rb_get_size(rb));
}
return rb;
}
size_t rb_get(rb_t *rb, void *dest, size_t n)
{
size_t size = rb_peek(rb, dest, n);
rb->size_filled -= size;
rb->off_r = (rb->off_r + size) % rb_get_size(rb);
if (rb->size_filled == 0) {
/* optimize space */
rb->off_w = rb->off_r = 0;
}
return size;
}
size_t rb_peek(const rb_t *rb, void *dest, size_t n)
{
uint16_t offset;
size_t size;
size_t size2;
if (rb->size_filled == 0 || n == 0) {
return 0;
}
size = 0;
if (rb->off_r >= rb->off_w) {
/* do not try to retrieve too much data */
size = MIN(n, rb_get_size(rb) - rb->off_r);
if (dest != NULL) {
memcpy(dest, &rb->buffer[rb->off_r], size);
}
dest += size;
n -= size;
}
offset = (rb->off_r + size) % rb_get_size(rb);
size2 = MIN(n, (size_t)(rb->off_w - offset));
if (dest != NULL) {
memcpy(dest, &rb->buffer[offset], size2);
}
return size + size2;
}
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