1/*	$NetBSD: buffer.h,v 1.5 2017/10/13 00:11:56 christos Exp $	*/
2
3/*-
4 * Copyright (c) 2005 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Christos Zoulas.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include <stddef.h>
33#include <stdio.h>
34#include <stdlib.h>
35#include <wchar.h>
36#include <err.h>
37
38#define BUF_SIZE	BUFSIZ
39struct buffer {
40	wchar_t *ptr;
41	wchar_t *bptr;
42	wchar_t *eptr;
43};
44
45static void
46buf_init(struct buffer *buf)
47{
48	buf->ptr = buf->bptr = calloc(BUF_SIZE, sizeof(*buf->ptr));
49	if (buf->ptr == NULL)
50		err(1, "Cannot allocate buffer");
51	buf->eptr = buf->ptr + BUF_SIZE;
52}
53
54static void
55buf_end(struct buffer *buf)
56{
57	free(buf->bptr);
58}
59
60static void
61buf_grow(struct buffer *buf, size_t minsize)
62{
63	ptrdiff_t diff;
64	size_t len = (buf->eptr - buf->bptr) +
65	    (minsize > BUF_SIZE ? minsize : BUF_SIZE);
66	wchar_t *nptr = realloc(buf->bptr, len * sizeof(*buf->ptr));
67
68	if (nptr == NULL)
69		err(1, "Cannot grow buffer");
70
71	if (nptr == buf->bptr) {
72		buf->eptr = buf->bptr + len;
73		return;
74	}
75
76	diff = nptr - buf->bptr;
77	buf->bptr += diff;
78	buf->eptr = buf->bptr + len;
79	buf->ptr += diff;
80}
81
82static inline void
83buf_putc(struct buffer *buf, wchar_t c)
84{
85	if (buf->ptr >= buf->eptr)
86		buf_grow(buf, 1);
87	*buf->ptr++ = c;
88}
89
90static inline void
91buf_reset(struct buffer *buf)
92{
93	buf->ptr = buf->bptr;
94}
95
96static inline wchar_t
97buf_unputc(struct buffer *buf)
98{
99	return buf->ptr > buf->bptr ? *--buf->ptr : '\0';
100}
101