xref: /freebsd/contrib/bmake/buf.c (revision cfd6422a5217410fbd66f7a7a8a64d9d85e61229)
1 /*	$NetBSD: buf.c,v 1.47 2020/12/30 10:03:16 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 character 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 1.47 2020/12/30 10:03:16 rillig Exp $");
79 
80 /* Make space in the buffer for adding at least 16 more bytes. */
81 void
82 Buf_Expand(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 /*
139  * Get the data (usually a string) from the buffer.
140  * The returned data is valid until the next modifying operation
141  * on the buffer.
142  *
143  * Returns the data and optionally the length of the data.
144  */
145 char *
146 Buf_GetAll(Buffer *buf, size_t *out_len)
147 {
148 	if (out_len != NULL)
149 		*out_len = buf->len;
150 	return buf->data;
151 }
152 
153 /* Mark the buffer as empty, so it can be filled with data again. */
154 void
155 Buf_Empty(Buffer *buf)
156 {
157 	buf->len = 0;
158 	buf->data[0] = '\0';
159 }
160 
161 /* Initialize a buffer. */
162 void
163 Buf_InitSize(Buffer *buf, size_t cap)
164 {
165 	buf->cap = cap;
166 	buf->len = 0;
167 	buf->data = bmake_malloc(cap);
168 	buf->data[0] = '\0';
169 }
170 
171 void
172 Buf_Init(Buffer *buf)
173 {
174 	Buf_InitSize(buf, 256);
175 }
176 
177 /*
178  * Reset the buffer.
179  * If freeData is TRUE, the data from the buffer is freed as well.
180  * Otherwise it is kept and returned.
181  */
182 char *
183 Buf_Destroy(Buffer *buf, Boolean freeData)
184 {
185 	char *data = buf->data;
186 	if (freeData) {
187 		free(data);
188 		data = NULL;
189 	}
190 
191 	buf->cap = 0;
192 	buf->len = 0;
193 	buf->data = NULL;
194 
195 	return data;
196 }
197 
198 #ifndef BUF_COMPACT_LIMIT
199 # define BUF_COMPACT_LIMIT 128	/* worthwhile saving */
200 #endif
201 
202 /*
203  * Reset the buffer and return its data.
204  *
205  * If the buffer size is much greater than its content,
206  * a new buffer will be allocated and the old one freed.
207  */
208 char *
209 Buf_DestroyCompact(Buffer *buf)
210 {
211 #if BUF_COMPACT_LIMIT > 0
212 	if (buf->cap - buf->len >= BUF_COMPACT_LIMIT) {
213 		/* We trust realloc to be smart */
214 		char *data = bmake_realloc(buf->data, buf->len + 1);
215 		data[buf->len] = '\0';	/* XXX: unnecessary */
216 		Buf_Destroy(buf, FALSE);
217 		return data;
218 	}
219 #endif
220 	return Buf_Destroy(buf, FALSE);
221 }
222