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;
127 static struct stackmark *markp;
134 stnewblock(int nbytes)
136 struct stack_block *sp;
139 if (nbytes < MINSIZE)
142 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
145 sp = ckmalloc(allocsize);
147 stacknxt = SPACE(sp);
148 stacknleft = allocsize - (stacknxt - (char*)sp);
149 sstrend = stacknxt + stacknleft;
160 nbytes = ALIGN(nbytes);
161 if (nbytes > stacknleft)
165 stacknleft -= nbytes;
173 if (p == NULL) { /*DEBUG */
174 write(STDERR_FILENO, "stunalloc\n", 10);
177 stacknleft += stacknxt - (char *)p;
184 setstackmark(struct stackmark *mark)
186 mark->stackp = stackp;
187 mark->stacknxt = stacknxt;
188 mark->stacknleft = stacknleft;
189 mark->marknext = markp;
195 popstackmark(struct stackmark *mark)
197 struct stack_block *sp;
200 markp = mark->marknext;
201 while (stackp != mark->stackp) {
206 stacknxt = mark->stacknxt;
207 stacknleft = mark->stacknleft;
208 sstrend = stacknxt + stacknleft;
214 * When the parser reads in a string, it wants to stick the string on the
215 * stack and only adjust the stack pointer when it knows how big the
216 * string is. Stackblock (defined in stack.h) returns a pointer to a block
217 * of space on top of the stack and stackblocklen returns the length of
218 * this block. Growstackblock will grow this space by at least one byte,
219 * possibly moving it (like realloc). Grabstackblock actually allocates the
220 * part of the block that has been used.
224 growstackblock(int min)
230 struct stack_block *sp;
231 struct stack_block *oldstackp;
232 struct stackmark *xmark;
234 if (min < stacknleft)
236 if (min >= INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
237 error("Out of space");
239 min += ALIGN(sizeof(struct stack_block));
246 if (stackp != NULL && stacknxt == SPACE(stackp)) {
249 stackp = oldstackp->prev;
250 sp = ckrealloc((pointer)oldstackp, newlen);
253 stacknxt = SPACE(sp);
254 stacknleft = newlen - (stacknxt - (char*)sp);
255 sstrend = stacknxt + stacknleft;
258 * Stack marks pointing to the start of the old block
259 * must be relocated to point to the new block
262 while (xmark != NULL && xmark->stackp == oldstackp) {
263 xmark->stackp = stackp;
264 xmark->stacknxt = stacknxt;
265 xmark->stacknleft = stacknleft;
266 xmark = xmark->marknext;
270 newlen -= ALIGN(sizeof(struct stack_block));
273 memcpy(p, oldspace, oldlen);
281 * The following routines are somewhat easier to use that the above.
282 * The user declares a variable of type STACKSTR, which may be declared
283 * to be a register. The macro STARTSTACKSTR initializes things. Then
284 * the user uses the macro STPUTC to add characters to the string. In
285 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
286 * grown as necessary. When the user is done, she can just leave the
287 * string there and refer to it using stackblock(). Or she can allocate
288 * the space for it using grabstackstr(). If it is necessary to allow
289 * someone else to use the stack temporarily and then continue to grow
290 * the string, the user should use grabstack to allocate the space, and
291 * then call ungrabstr(p) to return to the previous mode of operation.
293 * USTPUTC is like STPUTC except that it doesn't check for overflow.
294 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
295 * is space for at least one character.
299 growstrstackblock(int n, int min)
302 return stackblock() + n;
310 len = stackblocksize();
311 return (growstrstackblock(len, 0));
316 * Called from CHECKSTRSPACE.
320 makestrspace(int min, char *p)
324 len = p - stackblock();
325 return (growstrstackblock(len, min));
330 stputbin(const char *data, int len, char *p)
332 CHECKSTRSPACE(len, p);
333 memcpy(p, data, len);
338 stputs(const char *data, char *p)
340 return (stputbin(data, strlen(data), p));