buf.c revision 236769 
1/*	$NetBSD: buf.c,v 1.25 2012/04/24 20:26:58 sjg 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#ifndef MAKE_NATIVE
73static char rcsid[] = "$NetBSD: buf.c,v 1.25 2012/04/24 20:26:58 sjg Exp $";
74#else
75#include <sys/cdefs.h>
76#ifndef lint
77#if 0
78static char sccsid[] = "@(#)buf.c	8.1 (Berkeley) 6/6/93";
79#else
80__RCSID("$NetBSD: buf.c,v 1.25 2012/04/24 20:26:58 sjg Exp $");
81#endif
82#endif /* not lint */
83#endif
84
85/*-
86 * buf.c --
87 *	Functions for automatically-expanded buffers.
88 */
89
90#include    "make.h"
91#include    "buf.h"
92
93#ifndef max
94#define max(a,b)  ((a) > (b) ? (a) : (b))
95#endif
96
97#define BUF_DEF_SIZE	256 	/* Default buffer size */
98
99/*-
100 *-----------------------------------------------------------------------
101 * Buf_Expand_1 --
102 *	Extend buffer for single byte add.
103 *
104 *-----------------------------------------------------------------------
105 */
106void
107Buf_Expand_1(Buffer *bp)
108{
109    bp->size += max(bp->size, 16);
110    bp->buffer = bmake_realloc(bp->buffer, bp->size);
111}
112
113/*-
114 *-----------------------------------------------------------------------
115 * Buf_AddBytes --
116 *	Add a number of bytes to the buffer.
117 *
118 * Results:
119 *	None.
120 *
121 * Side Effects:
122 *	Guess what?
123 *
124 *-----------------------------------------------------------------------
125 */
126void
127Buf_AddBytes(Buffer *bp, int numBytes, const Byte *bytesPtr)
128{
129    int count = bp->count;
130    Byte *ptr;
131
132    if (__predict_false(count + numBytes >= bp->size)) {
133	bp->size += max(bp->size, numBytes + 16);
134	bp->buffer = bmake_realloc(bp->buffer, bp->size);
135    }
136
137    ptr = bp->buffer + count;
138    bp->count = count + numBytes;
139    ptr[numBytes] = 0;
140    memcpy(ptr, bytesPtr, numBytes);
141}
142
143/*-
144 *-----------------------------------------------------------------------
145 * Buf_GetAll --
146 *	Get all the available data at once.
147 *
148 * Results:
149 *	A pointer to the data and the number of bytes available.
150 *
151 * Side Effects:
152 *	None.
153 *
154 *-----------------------------------------------------------------------
155 */
156Byte *
157Buf_GetAll(Buffer *bp, int *numBytesPtr)
158{
159
160    if (numBytesPtr != NULL)
161	*numBytesPtr = bp->count;
162
163    return (bp->buffer);
164}
165
166/*-
167 *-----------------------------------------------------------------------
168 * Buf_Empty --
169 *	Throw away bytes in a buffer.
170 *
171 * Results:
172 *	None.
173 *
174 * Side Effects:
175 *	The bytes are discarded.
176 *
177 *-----------------------------------------------------------------------
178 */
179void
180Buf_Empty(Buffer *bp)
181{
182
183    bp->count = 0;
184    *bp->buffer = 0;
185}
186
187/*-
188 *-----------------------------------------------------------------------
189 * Buf_Init --
190 *	Initialize a buffer. If no initial size is given, a reasonable
191 *	default is used.
192 *
193 * Input:
194 *	size		Initial size for the buffer
195 *
196 * Results:
197 *	A buffer to be given to other functions in this library.
198 *
199 * Side Effects:
200 *	The buffer is created, the space allocated and pointers
201 *	initialized.
202 *
203 *-----------------------------------------------------------------------
204 */
205void
206Buf_Init(Buffer *bp, int size)
207{
208    if (size <= 0) {
209	size = BUF_DEF_SIZE;
210    }
211    bp->size = size;
212    bp->count = 0;
213    bp->buffer = bmake_malloc(size);
214    *bp->buffer = 0;
215}
216
217/*-
218 *-----------------------------------------------------------------------
219 * Buf_Destroy --
220 *	Nuke a buffer and all its resources.
221 *
222 * Input:
223 *	buf		Buffer to destroy
224 *	freeData	TRUE if the data should be destroyed
225 *
226 * Results:
227 *	Data buffer, NULL if freed
228 *
229 * Side Effects:
230 *	The buffer is freed.
231 *
232 *-----------------------------------------------------------------------
233 */
234Byte *
235Buf_Destroy(Buffer *buf, Boolean freeData)
236{
237    Byte *data;
238
239    data = buf->buffer;
240    if (freeData) {
241	free(data);
242	data = NULL;
243    }
244
245    buf->size = 0;
246    buf->count = 0;
247    buf->buffer = NULL;
248
249    return data;
250}
251
252
253/*-
254 *-----------------------------------------------------------------------
255 * Buf_DestroyCompact --
256 *	Nuke a buffer and return its data.
257 *
258 * Input:
259 *	buf		Buffer to destroy
260 *
261 * Results:
262 *	Data buffer
263 *
264 * Side Effects:
265 *	If the buffer size is much greater than its content,
266 *	a new buffer will be allocated and the old one freed.
267 *
268 *-----------------------------------------------------------------------
269 */
270#ifndef BUF_COMPACT_LIMIT
271# define BUF_COMPACT_LIMIT 128          /* worthwhile saving */
272#endif
273
274Byte *
275Buf_DestroyCompact(Buffer *buf)
276{
277#if BUF_COMPACT_LIMIT > 0
278    Byte *data;
279
280    if (buf->size - buf->count >= BUF_COMPACT_LIMIT) {
281	/* We trust realloc to be smart */
282	data = bmake_realloc(buf->buffer, buf->count + 1);
283	if (data) {
284	    data[buf->count] = 0;
285	    Buf_Destroy(buf, FALSE);
286	    return data;
287	}
288    }
289#endif
290    return Buf_Destroy(buf, FALSE);
291}
292