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
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9 * modification, are permitted provided that the following conditions
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12 * notice, this list of conditions and the following disclaimer.
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15 * documentation and/or other materials provided with the distribution.
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20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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35 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 #include <sys/param.h>
52 * Like malloc, but returns an error when out of space.
56 ckmalloc(size_t nbytes)
64 error("Out of space");
74 ckrealloc(pointer p, int nbytes)
77 p = realloc(p, nbytes);
80 error("Out of space");
94 * Make a copy of a string in safe storage.
98 savestr(const char *s)
104 p = ckmalloc(len + 1);
105 memcpy(p, s, len + 1);
111 * Parse trees for commands are allocated in lifo order, so we use a stack
112 * to make this more efficient, and also to avoid all sorts of exception
113 * handling code to handle interrupts in the middle of a parse.
115 * The size 496 was chosen because with 16-byte alignment the total size
116 * for the allocated block is 512.
119 #define MINSIZE 496 /* minimum size of a block. */
123 struct stack_block *prev;
126 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block)))
128 static struct stack_block *stackp;
135 stnewblock(int nbytes)
137 struct stack_block *sp;
140 if (nbytes < MINSIZE)
143 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
146 sp = ckmalloc(allocsize);
148 stacknxt = SPACE(sp);
149 stacknleft = allocsize - (stacknxt - (char*)sp);
150 sstrend = stacknxt + stacknleft;
161 nbytes = ALIGN(nbytes);
162 if (nbytes > stacknleft)
166 stacknleft -= nbytes;
174 if (p == NULL) { /*DEBUG */
175 write(STDERR_FILENO, "stunalloc\n", 10);
178 stacknleft += stacknxt - (char *)p;
184 stsavestr(const char *s)
190 p = stalloc(len + 1);
191 memcpy(p, s, len + 1);
197 setstackmark(struct stackmark *mark)
199 mark->stackp = stackp;
200 mark->stacknxt = stacknxt;
201 mark->stacknleft = stacknleft;
202 /* Ensure this block stays in place. */
203 if (stackp != NULL && stacknxt == SPACE(stackp))
209 popstackmark(struct stackmark *mark)
211 struct stack_block *sp;
214 while (stackp != mark->stackp) {
219 stacknxt = mark->stacknxt;
220 stacknleft = mark->stacknleft;
221 sstrend = stacknxt + stacknleft;
227 * When the parser reads in a string, it wants to stick the string on the
228 * stack and only adjust the stack pointer when it knows how big the
229 * string is. Stackblock (defined in stack.h) returns a pointer to a block
230 * of space on top of the stack and stackblocklen returns the length of
231 * this block. Growstackblock will grow this space by at least one byte,
232 * possibly moving it (like realloc). Grabstackblock actually allocates the
233 * part of the block that has been used.
237 growstackblock(int min)
243 struct stack_block *sp;
244 struct stack_block *oldstackp;
246 if (min < stacknleft)
248 if ((unsigned int)min >=
249 INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
250 error("Out of space");
252 min += ALIGN(sizeof(struct stack_block));
259 if (stackp != NULL && stacknxt == SPACE(stackp)) {
262 stackp = oldstackp->prev;
263 sp = ckrealloc((pointer)oldstackp, newlen);
266 stacknxt = SPACE(sp);
267 stacknleft = newlen - (stacknxt - (char*)sp);
268 sstrend = stacknxt + stacknleft;
271 newlen -= ALIGN(sizeof(struct stack_block));
274 memcpy(p, oldspace, oldlen);
282 * The following routines are somewhat easier to use that the above.
283 * The user declares a variable of type STACKSTR, which may be declared
284 * to be a register. The macro STARTSTACKSTR initializes things. Then
285 * the user uses the macro STPUTC to add characters to the string. In
286 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
287 * grown as necessary. When the user is done, she can just leave the
288 * string there and refer to it using stackblock(). Or she can allocate
289 * the space for it using grabstackstr(). If it is necessary to allow
290 * someone else to use the stack temporarily and then continue to grow
291 * the string, the user should use grabstack to allocate the space, and
292 * then call ungrabstr(p) to return to the previous mode of operation.
294 * USTPUTC is like STPUTC except that it doesn't check for overflow.
295 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
296 * is space for at least one character.
300 growstrstackblock(int n, int min)
303 return stackblock() + n;
311 len = stackblocksize();
312 return (growstrstackblock(len, 0));
317 * Called from CHECKSTRSPACE.
321 makestrspace(int min, char *p)
325 len = p - stackblock();
326 return (growstrstackblock(len, min));
331 stputbin(const char *data, size_t len, char *p)
333 CHECKSTRSPACE(len, p);
334 memcpy(p, data, len);
339 stputs(const char *data, char *p)
341 return (stputbin(data, strlen(data), p));