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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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)
102 p = ckmalloc(strlen(s) + 1);
109 * Parse trees for commands are allocated in lifo order, so we use a stack
110 * to make this more efficient, and also to avoid all sorts of exception
111 * handling code to handle interrupts in the middle of a parse.
113 * The size 496 was chosen because with 16-byte alignment the total size
114 * for the allocated block is 512.
117 #define MINSIZE 496 /* minimum size of a block. */
121 struct stack_block *prev;
124 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block)))
126 static struct stack_block *stackp;
133 stnewblock(int nbytes)
135 struct stack_block *sp;
138 if (nbytes < MINSIZE)
141 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
144 sp = ckmalloc(allocsize);
146 stacknxt = SPACE(sp);
147 stacknleft = allocsize - (stacknxt - (char*)sp);
148 sstrend = stacknxt + stacknleft;
159 nbytes = ALIGN(nbytes);
160 if (nbytes > stacknleft)
164 stacknleft -= nbytes;
172 if (p == NULL) { /*DEBUG */
173 write(STDERR_FILENO, "stunalloc\n", 10);
176 stacknleft += stacknxt - (char *)p;
183 setstackmark(struct stackmark *mark)
185 mark->stackp = stackp;
186 mark->stacknxt = stacknxt;
187 mark->stacknleft = stacknleft;
188 /* Ensure this block stays in place. */
189 if (stackp != NULL && stacknxt == SPACE(stackp))
195 popstackmark(struct stackmark *mark)
197 struct stack_block *sp;
200 while (stackp != mark->stackp) {
205 stacknxt = mark->stacknxt;
206 stacknleft = mark->stacknleft;
207 sstrend = stacknxt + stacknleft;
213 * When the parser reads in a string, it wants to stick the string on the
214 * stack and only adjust the stack pointer when it knows how big the
215 * string is. Stackblock (defined in stack.h) returns a pointer to a block
216 * of space on top of the stack and stackblocklen returns the length of
217 * this block. Growstackblock will grow this space by at least one byte,
218 * possibly moving it (like realloc). Grabstackblock actually allocates the
219 * part of the block that has been used.
223 growstackblock(int min)
229 struct stack_block *sp;
230 struct stack_block *oldstackp;
232 if (min < stacknleft)
234 if ((unsigned int)min >=
235 INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
236 error("Out of space");
238 min += ALIGN(sizeof(struct stack_block));
245 if (stackp != NULL && stacknxt == SPACE(stackp)) {
248 stackp = oldstackp->prev;
249 sp = ckrealloc((pointer)oldstackp, newlen);
252 stacknxt = SPACE(sp);
253 stacknleft = newlen - (stacknxt - (char*)sp);
254 sstrend = stacknxt + stacknleft;
257 newlen -= ALIGN(sizeof(struct stack_block));
260 memcpy(p, oldspace, oldlen);
268 * The following routines are somewhat easier to use that the above.
269 * The user declares a variable of type STACKSTR, which may be declared
270 * to be a register. The macro STARTSTACKSTR initializes things. Then
271 * the user uses the macro STPUTC to add characters to the string. In
272 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
273 * grown as necessary. When the user is done, she can just leave the
274 * string there and refer to it using stackblock(). Or she can allocate
275 * the space for it using grabstackstr(). If it is necessary to allow
276 * someone else to use the stack temporarily and then continue to grow
277 * the string, the user should use grabstack to allocate the space, and
278 * then call ungrabstr(p) to return to the previous mode of operation.
280 * USTPUTC is like STPUTC except that it doesn't check for overflow.
281 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
282 * is space for at least one character.
286 growstrstackblock(int n, int min)
289 return stackblock() + n;
297 len = stackblocksize();
298 return (growstrstackblock(len, 0));
303 * Called from CHECKSTRSPACE.
307 makestrspace(int min, char *p)
311 len = p - stackblock();
312 return (growstrstackblock(len, min));
317 stputbin(const char *data, size_t len, char *p)
319 CHECKSTRSPACE(len, p);
320 memcpy(p, data, len);
325 stputs(const char *data, char *p)
327 return (stputbin(data, strlen(data), p));