1 /* $NetBSD: buffer.h,v 1.4 2008/04/28 20:24:12 martin 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 <err.h>
36
37 #define BUF_SIZE BUFSIZ
38 struct buffer {
39 char *ptr;
40 char *bptr;
41 char *eptr;
42 };
43
44 static void
buf_init(struct buffer * buf)45 buf_init(struct buffer *buf)
46 {
47 buf->ptr = buf->bptr = malloc(BUF_SIZE);
48 if (buf->ptr == NULL)
49 err(1, "Cannot allocate buffer");
50 buf->eptr = buf->ptr + BUF_SIZE;
51 }
52
53 static void
buf_end(struct buffer * buf)54 buf_end(struct buffer *buf)
55 {
56 free(buf->bptr);
57 }
58
59 static void
buf_grow(struct buffer * buf,size_t minsize)60 buf_grow(struct buffer *buf, size_t minsize)
61 {
62 ptrdiff_t diff;
63 size_t len = (buf->eptr - buf->bptr) +
64 (minsize > BUF_SIZE ? minsize : BUF_SIZE);
65 char *nptr = realloc(buf->bptr, len);
66
67 if (nptr == NULL)
68 err(1, "Cannot grow buffer");
69
70 if (nptr == buf->bptr) {
71 buf->eptr = buf->bptr + len;
72 return;
73 }
74
75 diff = nptr - buf->bptr;
76 buf->bptr += diff;
77 buf->eptr = buf->bptr + len;
78 buf->ptr += diff;
79 }
80
81 static inline void
buf_putc(struct buffer * buf,char c)82 buf_putc(struct buffer *buf, char c)
83 {
84 if (buf->ptr >= buf->eptr)
85 buf_grow(buf, 1);
86 *buf->ptr++ = c;
87 }
88
89 static inline void
buf_reset(struct buffer * buf)90 buf_reset(struct buffer *buf)
91 {
92 buf->ptr = buf->bptr;
93 }
94
95 static inline char
buf_unputc(struct buffer * buf)96 buf_unputc(struct buffer *buf)
97 {
98 return buf->ptr > buf->bptr ? *--buf->ptr : '\0';
99 }
100