xref: /freebsd/usr.bin/mail/strings.c (revision 4b9d6057)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1980, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 /*
33  * Mail -- a mail program
34  *
35  * String allocation routines.
36  * Strings handed out here are reclaimed at the top of the command
37  * loop each time, so they need not be freed.
38  */
39 
40 #include "rcv.h"
41 #include "extern.h"
42 
43 struct strings stringdope[NSPACE];
44 
45 /*
46  * Allocate size more bytes of space and return the address of the
47  * first byte to the caller.  An even number of bytes are always
48  * allocated so that the space will always be on a word boundary.
49  * The string spaces are of exponentially increasing size, to satisfy
50  * the occasional user with enormous string size requests.
51  */
52 
53 char *
54 salloc(int size)
55 {
56 	char *t;
57 	int s, index;
58 	struct strings *sp;
59 
60 	s = size;
61 	s += (sizeof(char *) - 1);
62 	s &= ~(sizeof(char *) - 1);
63 	index = 0;
64 	for (sp = &stringdope[0]; sp < &stringdope[NSPACE]; sp++) {
65 		if (sp->s_topFree == NULL && (STRINGSIZE << index) >= s)
66 			break;
67 		if (sp->s_nleft >= s)
68 			break;
69 		index++;
70 	}
71 	if (sp >= &stringdope[NSPACE])
72 		errx(1, "String too large");
73 	if (sp->s_topFree == NULL) {
74 		index = sp - &stringdope[0];
75 		if ((sp->s_topFree = malloc(STRINGSIZE << index)) == NULL)
76 			err(1, "No room for space %d", index);
77 		sp->s_nextFree = sp->s_topFree;
78 		sp->s_nleft = STRINGSIZE << index;
79 	}
80 	sp->s_nleft -= s;
81 	t = sp->s_nextFree;
82 	sp->s_nextFree += s;
83 	return (t);
84 }
85 
86 /*
87  * Reset the string area to be empty.
88  * Called to free all strings allocated
89  * since last reset.
90  */
91 void
92 sreset(void)
93 {
94 	struct strings *sp;
95 	int index;
96 
97 	if (noreset)
98 		return;
99 	index = 0;
100 	for (sp = &stringdope[0]; sp < &stringdope[NSPACE]; sp++) {
101 		if (sp->s_topFree == NULL)
102 			continue;
103 		sp->s_nextFree = sp->s_topFree;
104 		sp->s_nleft = STRINGSIZE << index;
105 		index++;
106 	}
107 }
108 
109 /*
110  * Make the string area permanent.
111  * Meant to be called in main, after initialization.
112  */
113 void
114 spreserve(void)
115 {
116 	struct strings *sp;
117 
118 	for (sp = &stringdope[0]; sp < &stringdope[NSPACE]; sp++)
119 		sp->s_topFree = NULL;
120 }
121