Files
Cescal/core/tokbuf.c
T
2026-05-23 02:57:50 -04:00

63 lines
1.0 KiB
C

/*
* Copyright (c) 2026, Chloe M.
* Provided under the BSD-3 clause
*/
#include <sys/types.h>
#include <stdint.h>
#include <stddef.h>
#include <string.h>
#include <errno.h>
#include "cescal/tokbuf.h"
int
tokbuf_init(struct tokbuf *tokbuf)
{
if (tokbuf == NULL) {
errno = EINVAL;
return -1;
}
memset(tokbuf->buf, 0, sizeof(tokbuf->buf));
tokbuf->head = 0;
return 0;
}
int
tokbuf_push(struct tokbuf *tokbuf, struct token *tok)
{
if (tokbuf == NULL || tok == NULL) {
return -1;
}
if ((tokbuf->head++) >= TOKBUF_CAP) {
tokbuf->head = 0;
}
tokbuf->buf[tokbuf->head] = *tok;
return 0;
}
int
tokbuf_noff(struct tokbuf *tokbuf, size_t noff, struct token *res)
{
ssize_t off;
if (tokbuf == NULL || res == NULL) {
errno = EINVAL;
return -1;
}
if (noff == 0) {
*res = tokbuf->buf[tokbuf->head + 1];
return 0;
}
if ((off = (tokbuf->head - noff + 1)) < 0) {
off = 0;
}
*res = tokbuf->buf[off];
return 0;
}