#include <malloc.h>
#include <string.h>
#include <stdio.h>
#include "foobuf.h"

int foobuf_init(struct foobuf **bufp, size_t len)
{
	struct foobuf *buf = *bufp;
	if (!buf) {
		buf = calloc(sizeof *buf, 1);
		if (!buf) return 1;
		*bufp = buf;
		buf->data = calloc(len, sizeof(float));
		if (!buf->data) return 1;
		buf->len = len;
	} else if (buf->len != len) {
		buf->data = realloc(buf->data, len * sizeof(float));
		if (!buf->data) return 1;
		if (len > buf->len) {
			memset(&buf->data[buf->len], 0, len - buf->len);
		} else {
			if (buf->offset >= len) buf->offset = 0;
		}
		buf->len = len;
	}
	return 0;
}

float foobuf_read(struct foobuf *buf, size_t offset)
{
	size_t len = buf->len;
	return buf->data[((buf->offset - offset) + len) % len];
}

void foobuf_write(struct foobuf *buf, float val)
{
	if (!buf || !buf->data) return;
	size_t offset = buf->offset;
	buf->data[offset] = val;
	offset++;
	if (offset == buf->len) offset = 0;
	buf->offset = offset;
}

int _struct_init(void **ptr, size_t size)
{
	if (*ptr) return 0;
	if ((*ptr = calloc(1, size))) return 0;
	return 1;
}