xref: /netbsd-src/usr.bin/make/buf.c (revision 9fd8799cb5ceb66c69f2eb1a6d26a1d587ba1f1e)
1 /*	$NetBSD: buf.c,v 1.45 2020/11/23 19:07:12 rillig Exp $	*/
2 
3 /*
4  * Copyright (c) 1988, 1989, 1990 The Regents of the University of California.
5  * All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Adam de Boor.
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  * 3. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 /*
36  * Copyright (c) 1988, 1989 by Adam de Boor
37  * Copyright (c) 1989 by Berkeley Softworks
38  * All rights reserved.
39  *
40  * This code is derived from software contributed to Berkeley by
41  * Adam de Boor.
42  *
43  * Redistribution and use in source and binary forms, with or without
44  * modification, are permitted provided that the following conditions
45  * are met:
46  * 1. Redistributions of source code must retain the above copyright
47  *    notice, this list of conditions and the following disclaimer.
48  * 2. Redistributions in binary form must reproduce the above copyright
49  *    notice, this list of conditions and the following disclaimer in the
50  *    documentation and/or other materials provided with the distribution.
51  * 3. All advertising materials mentioning features or use of this software
52  *    must display the following acknowledgement:
53  *	This product includes software developed by the University of
54  *	California, Berkeley and its contributors.
55  * 4. Neither the name of the University nor the names of its contributors
56  *    may be used to endorse or promote products derived from this software
57  *    without specific prior written permission.
58  *
59  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
60  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
61  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
62  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
63  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
64  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
65  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
66  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
67  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
68  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
69  * SUCH DAMAGE.
70  */
71 
72 /* Automatically-expanding null-terminated buffers. */
73 
74 #include <limits.h>
75 #include "make.h"
76 
77 /*	"@(#)buf.c	8.1 (Berkeley) 6/6/93"	*/
78 MAKE_RCSID("$NetBSD: buf.c,v 1.45 2020/11/23 19:07:12 rillig Exp $");
79 
80 /* Make space in the buffer for adding a single byte. */
81 void
82 Buf_Expand_1(Buffer *buf)
83 {
84 	buf->cap += buf->cap > 16 ? buf->cap : 16;
85 	buf->data = bmake_realloc(buf->data, buf->cap);
86 }
87 
88 /* Add the bytes to the buffer. */
89 void
90 Buf_AddBytes(Buffer *buf, const char *bytes, size_t bytes_len)
91 {
92 	size_t old_len = buf->len;
93 	char *end;
94 
95 	if (__predict_false(old_len + bytes_len >= buf->cap)) {
96 		size_t minIncr = bytes_len + 16;
97 		buf->cap += buf->cap > minIncr ? buf->cap : minIncr;
98 		buf->data = bmake_realloc(buf->data, buf->cap);
99 	}
100 
101 	end = buf->data + old_len;
102 	buf->len = old_len + bytes_len;
103 	memcpy(end, bytes, bytes_len);
104 	end[bytes_len] = '\0';
105 }
106 
107 /* Add the bytes between start and end to the buffer. */
108 void
109 Buf_AddBytesBetween(Buffer *buf, const char *start, const char *end)
110 {
111 	Buf_AddBytes(buf, start, (size_t)(end - start));
112 }
113 
114 /* Add the string to the buffer. */
115 void
116 Buf_AddStr(Buffer *buf, const char *str)
117 {
118 	Buf_AddBytes(buf, str, strlen(str));
119 }
120 
121 /* Add the number to the buffer. */
122 void
123 Buf_AddInt(Buffer *buf, int n)
124 {
125 	enum {
126 		bits = sizeof(int) * CHAR_BIT,
127 		max_octal_digits = (bits + 2) / 3,
128 		max_decimal_digits = /* at most */ max_octal_digits,
129 		max_sign_chars = 1,
130 		str_size = max_sign_chars + max_decimal_digits + 1
131 	};
132 	char str[str_size];
133 
134 	size_t len = (size_t)snprintf(str, sizeof str, "%d", n);
135 	Buf_AddBytes(buf, str, len);
136 }
137 
138 /* Get the data (usually a string) from the buffer.
139  * The returned data is valid until the next modifying operation
140  * on the buffer.
141  *
142  * Returns the data and optionally the length of the data. */
143 char *
144 Buf_GetAll(Buffer *buf, size_t *out_len)
145 {
146 	if (out_len != NULL)
147 		*out_len = buf->len;
148 	return buf->data;
149 }
150 
151 /* Mark the buffer as empty, so it can be filled with data again. */
152 void
153 Buf_Empty(Buffer *buf)
154 {
155 	buf->len = 0;
156 	buf->data[0] = '\0';
157 }
158 
159 /* Initialize a buffer. */
160 void
161 Buf_InitSize(Buffer *buf, size_t cap)
162 {
163 	buf->cap = cap;
164 	buf->len = 0;
165 	buf->data = bmake_malloc(cap);
166 	buf->data[0] = '\0';
167 }
168 
169 void
170 Buf_Init(Buffer *buf)
171 {
172 	Buf_InitSize(buf, 256);
173 }
174 
175 /* Reset the buffer.
176  * If freeData is TRUE, the data from the buffer is freed as well.
177  * Otherwise it is kept and returned. */
178 char *
179 Buf_Destroy(Buffer *buf, Boolean freeData)
180 {
181 	char *data = buf->data;
182 	if (freeData) {
183 		free(data);
184 		data = NULL;
185 	}
186 
187 	buf->cap = 0;
188 	buf->len = 0;
189 	buf->data = NULL;
190 
191 	return data;
192 }
193 
194 #ifndef BUF_COMPACT_LIMIT
195 # define BUF_COMPACT_LIMIT 128	/* worthwhile saving */
196 #endif
197 
198 /* Reset the buffer and return its data.
199  *
200  * If the buffer size is much greater than its content,
201  * a new buffer will be allocated and the old one freed. */
202 char *
203 Buf_DestroyCompact(Buffer *buf)
204 {
205 #if BUF_COMPACT_LIMIT > 0
206 	if (buf->cap - buf->len >= BUF_COMPACT_LIMIT) {
207 		/* We trust realloc to be smart */
208 		char *data = bmake_realloc(buf->data, buf->len + 1);
209 		data[buf->len] = '\0';	/* XXX: unnecessary */
210 		Buf_Destroy(buf, FALSE);
211 		return data;
212 	}
213 #endif
214 	return Buf_Destroy(buf, FALSE);
215 }
216