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)
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;
185 setstackmark(struct stackmark *mark)
187 mark->stackp = stackp;
188 mark->stacknxt = stacknxt;
189 mark->stacknleft = stacknleft;
190 /* Ensure this block stays in place. */
191 if (stackp != NULL && stacknxt == SPACE(stackp))
197 popstackmark(struct stackmark *mark)
199 struct stack_block *sp;
202 while (stackp != mark->stackp) {
207 stacknxt = mark->stacknxt;
208 stacknleft = mark->stacknleft;
209 sstrend = stacknxt + stacknleft;
215 * When the parser reads in a string, it wants to stick the string on the
216 * stack and only adjust the stack pointer when it knows how big the
217 * string is. Stackblock (defined in stack.h) returns a pointer to a block
218 * of space on top of the stack and stackblocklen returns the length of
219 * this block. Growstackblock will grow this space by at least one byte,
220 * possibly moving it (like realloc). Grabstackblock actually allocates the
221 * part of the block that has been used.
225 growstackblock(int min)
231 struct stack_block *sp;
232 struct stack_block *oldstackp;
234 if (min < stacknleft)
236 if ((unsigned int)min >=
237 INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
238 error("Out of space");
240 min += ALIGN(sizeof(struct stack_block));
247 if (stackp != NULL && stacknxt == SPACE(stackp)) {
250 stackp = oldstackp->prev;
251 sp = ckrealloc((pointer)oldstackp, newlen);
254 stacknxt = SPACE(sp);
255 stacknleft = newlen - (stacknxt - (char*)sp);
256 sstrend = stacknxt + stacknleft;
259 newlen -= ALIGN(sizeof(struct stack_block));
262 memcpy(p, oldspace, oldlen);
270 * The following routines are somewhat easier to use that the above.
271 * The user declares a variable of type STACKSTR, which may be declared
272 * to be a register. The macro STARTSTACKSTR initializes things. Then
273 * the user uses the macro STPUTC to add characters to the string. In
274 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
275 * grown as necessary. When the user is done, she can just leave the
276 * string there and refer to it using stackblock(). Or she can allocate
277 * the space for it using grabstackstr(). If it is necessary to allow
278 * someone else to use the stack temporarily and then continue to grow
279 * the string, the user should use grabstack to allocate the space, and
280 * then call ungrabstr(p) to return to the previous mode of operation.
282 * USTPUTC is like STPUTC except that it doesn't check for overflow.
283 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
284 * is space for at least one character.
288 growstrstackblock(int n, int min)
291 return stackblock() + n;
299 len = stackblocksize();
300 return (growstrstackblock(len, 0));
305 * Called from CHECKSTRSPACE.
309 makestrspace(int min, char *p)
313 len = p - stackblock();
314 return (growstrstackblock(len, min));
319 stputbin(const char *data, size_t len, char *p)
321 CHECKSTRSPACE(len, p);
322 memcpy(p, data, len);
327 stputs(const char *data, char *p)
329 return (stputbin(data, strlen(data), p));