2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
39 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
41 static const char rcsid[] =
42 "$Id: memalloc.c,v 1.11 1998/09/10 14:51:06 cracauer Exp $";
56 * Like malloc, but returns an error when out of space.
65 if ((p = malloc(nbytes)) == NULL)
66 error("Out of space");
81 if ((p = realloc(p, nbytes)) == NULL)
82 error("Out of space");
88 * Make a copy of a string in safe storage.
97 p = ckmalloc(strlen(s) + 1);
104 * Parse trees for commands are allocated in lifo order, so we use a stack
105 * to make this more efficient, and also to avoid all sorts of exception
106 * handling code to handle interrupts in the middle of a parse.
108 * The size 504 was chosen because the Ultrix malloc handles that size
112 #define MINSIZE 504 /* minimum size of a block */
116 struct stack_block *prev;
120 struct stack_block stackbase;
121 struct stack_block *stackp = &stackbase;
122 char *stacknxt = stackbase.space;
123 int stacknleft = MINSIZE;
135 nbytes = ALIGN(nbytes);
136 if (nbytes > stacknleft) {
138 struct stack_block *sp;
141 if (blocksize < MINSIZE)
144 sp = ckmalloc(sizeof(struct stack_block) - MINSIZE + blocksize);
146 stacknxt = sp->space;
147 stacknleft = blocksize;
153 stacknleft -= nbytes;
162 if (p == NULL) { /*DEBUG */
163 write(2, "stunalloc\n", 10);
166 stacknleft += stacknxt - (char *)p;
174 struct stackmark *mark;
176 mark->stackp = stackp;
177 mark->stacknxt = stacknxt;
178 mark->stacknleft = stacknleft;
184 struct stackmark *mark;
186 struct stack_block *sp;
189 while (stackp != mark->stackp) {
194 stacknxt = mark->stacknxt;
195 stacknleft = mark->stacknleft;
201 * When the parser reads in a string, it wants to stick the string on the
202 * stack and only adjust the stack pointer when it knows how big the
203 * string is. Stackblock (defined in stack.h) returns a pointer to a block
204 * of space on top of the stack and stackblocklen returns the length of
205 * this block. Growstackblock will grow this space by at least one byte,
206 * possibly moving it (like realloc). Grabstackblock actually allocates the
207 * part of the block that has been used.
213 int newlen = ALIGN(stacknleft * 2 + 100);
214 char *oldspace = stacknxt;
215 int oldlen = stacknleft;
216 struct stack_block *sp;
218 if (stacknxt == stackp->space && stackp != &stackbase) {
222 sp = ckrealloc((pointer)sp, sizeof(struct stack_block) - MINSIZE + newlen);
225 stacknxt = sp->space;
230 memcpy(p, oldspace, oldlen);
231 stacknxt = p; /* free the space */
232 stacknleft += newlen; /* we just allocated */
250 * The following routines are somewhat easier to use that the above.
251 * The user declares a variable of type STACKSTR, which may be declared
252 * to be a register. The macro STARTSTACKSTR initializes things. Then
253 * the user uses the macro STPUTC to add characters to the string. In
254 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
255 * grown as necessary. When the user is done, she can just leave the
256 * string there and refer to it using stackblock(). Or she can allocate
257 * the space for it using grabstackstr(). If it is necessary to allow
258 * someone else to use the stack temporarily and then continue to grow
259 * the string, the user should use grabstack to allocate the space, and
260 * then call ungrabstr(p) to return to the previous mode of operation.
262 * USTPUTC is like STPUTC except that it doesn't check for overflow.
263 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
264 * is space for at least one character.
270 int len = stackblocksize();
271 if (herefd >= 0 && len >= 1024) {
272 xwrite(herefd, stackblock(), len);
277 sstrnleft = stackblocksize() - len - 1;
278 return stackblock() + len;
283 * Called from CHECKSTRSPACE.
288 int len = stackblocksize() - sstrnleft;
290 sstrnleft = stackblocksize() - len;
291 return stackblock() + len;
301 stacknleft += stacknxt - s;
303 sstrnleft = stacknleft - (p - s);