You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
101 lines
1.5 KiB
101 lines
1.5 KiB
#include <stdint.h>
|
|
#include <stdbool.h>
|
|
#include <string.h>
|
|
#include <malloc.h>
|
|
|
|
#include "circbuf.h"
|
|
|
|
|
|
void cbuf_init(circbuf_t *inst, size_t capacity)
|
|
{
|
|
inst->buf = malloc(capacity);
|
|
inst->cap = capacity;
|
|
|
|
cbuf_clear(inst);
|
|
}
|
|
|
|
|
|
void cbuf_deinit(circbuf_t *inst)
|
|
{
|
|
if (inst->buf != NULL) {
|
|
free(inst->buf);
|
|
}
|
|
}
|
|
|
|
|
|
bool cbuf_full(circbuf_t *inst)
|
|
{
|
|
return (inst->lr == inst->nw);
|
|
}
|
|
|
|
|
|
static bool can_read_at(circbuf_t *inst, size_t i)
|
|
{
|
|
if (inst->lr < inst->nw) {
|
|
return i > inst->lr && i < inst->nw;
|
|
} else {
|
|
// NW < LR
|
|
return (i < inst->cap && i > inst->lr) || i < inst->nw;
|
|
}
|
|
}
|
|
|
|
|
|
bool cbuf_empty(circbuf_t *inst)
|
|
{
|
|
return ((inst->lr + 1) % inst->cap) == inst->nw;
|
|
}
|
|
|
|
|
|
bool cbuf_write(circbuf_t *inst, uint8_t b)
|
|
{
|
|
if (cbuf_full(inst)) return false;
|
|
|
|
inst->buf[inst->nw] = b;
|
|
|
|
// increment
|
|
inst->nw++;
|
|
if (inst->nw == inst->cap) inst->nw = 0;
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
bool cbuf_read(circbuf_t *inst, uint8_t *b)
|
|
{
|
|
if (cbuf_empty(inst)) return false;
|
|
|
|
// increment
|
|
inst->lr++;
|
|
if (inst->lr == inst->cap) inst->lr = 0;
|
|
|
|
*b = inst->buf[inst->lr];
|
|
|
|
//zero out the read byte (for debug)
|
|
inst->buf[inst->lr] = 0;
|
|
|
|
return true;
|
|
}
|
|
|
|
|
|
bool cbuf_peek(circbuf_t *inst, size_t nth, uint8_t *b)
|
|
{
|
|
// check if can read there (can't use module, could "wrap")
|
|
size_t n = inst->lr;
|
|
for (size_t i = 0; i <= nth; i++) {
|
|
// increment N
|
|
n++;
|
|
if (n == inst->cap) n = 0;
|
|
|
|
if (!can_read_at(inst, n)) return false;
|
|
}
|
|
|
|
*b = inst->buf[n];
|
|
return true;
|
|
}
|
|
|
|
|
|
void cbuf_clear(circbuf_t *inst)
|
|
{
|
|
inst->lr = inst->cap - 1;
|
|
inst->nw = 0;
|
|
}
|
|
|