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37 static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
40 #include <sys/cdefs.h>
41 #include <sys/param.h>
52 badalloc(const char *message)
54 write(2, message, strlen(message));
59 * Like malloc, but returns an error when out of space.
63 ckmalloc(size_t nbytes)
68 badalloc("Unsafe ckmalloc() call\n");
71 error("Out of space");
81 ckrealloc(pointer p, int nbytes)
84 badalloc("Unsafe ckrealloc() call\n");
85 p = realloc(p, nbytes);
87 error("Out of space");
95 badalloc("Unsafe ckfree() call\n");
101 * Make a copy of a string in safe storage.
105 savestr(const char *s)
111 p = ckmalloc(len + 1);
112 memcpy(p, s, len + 1);
118 * Parse trees for commands are allocated in lifo order, so we use a stack
119 * to make this more efficient, and also to avoid all sorts of exception
120 * handling code to handle interrupts in the middle of a parse.
122 * The size 496 was chosen because with 16-byte alignment the total size
123 * for the allocated block is 512.
126 #define MINSIZE 496 /* minimum size of a block. */
130 struct stack_block *prev;
133 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block)))
135 static struct stack_block *stackp;
142 stnewblock(int nbytes)
144 struct stack_block *sp;
147 if (nbytes < MINSIZE)
150 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
153 sp = ckmalloc(allocsize);
155 stacknxt = SPACE(sp);
156 stacknleft = allocsize - (stacknxt - (char*)sp);
157 sstrend = stacknxt + stacknleft;
168 nbytes = ALIGN(nbytes);
169 if (nbytes > stacknleft)
173 stacknleft -= nbytes;
181 if (p == NULL) { /*DEBUG */
182 write(STDERR_FILENO, "stunalloc\n", 10);
185 stacknleft += stacknxt - (char *)p;
191 stsavestr(const char *s)
197 p = stalloc(len + 1);
198 memcpy(p, s, len + 1);
204 setstackmark(struct stackmark *mark)
206 mark->stackp = stackp;
207 mark->stacknxt = stacknxt;
208 mark->stacknleft = stacknleft;
209 /* Ensure this block stays in place. */
210 if (stackp != NULL && stacknxt == SPACE(stackp))
216 popstackmark(struct stackmark *mark)
218 struct stack_block *sp;
221 while (stackp != mark->stackp) {
226 stacknxt = mark->stacknxt;
227 stacknleft = mark->stacknleft;
229 sstrend = stacknxt + stacknleft;
237 * When the parser reads in a string, it wants to stick the string on the
238 * stack and only adjust the stack pointer when it knows how big the
239 * string is. Stackblock (defined in stack.h) returns a pointer to a block
240 * of space on top of the stack and stackblocklen returns the length of
241 * this block. Growstackblock will grow this space by at least one byte,
242 * possibly moving it (like realloc). Grabstackblock actually allocates the
243 * part of the block that has been used.
247 growstackblock(int min)
253 struct stack_block *sp;
254 struct stack_block *oldstackp;
256 if (min < stacknleft)
258 if ((unsigned int)min >=
259 INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
260 error("Out of space");
262 min += ALIGN(sizeof(struct stack_block));
269 if (stackp != NULL && stacknxt == SPACE(stackp)) {
272 stackp = oldstackp->prev;
273 sp = ckrealloc((pointer)oldstackp, newlen);
276 stacknxt = SPACE(sp);
277 stacknleft = newlen - (stacknxt - (char*)sp);
278 sstrend = stacknxt + stacknleft;
281 newlen -= ALIGN(sizeof(struct stack_block));
284 memcpy(p, oldspace, oldlen);
292 * The following routines are somewhat easier to use that the above.
293 * The user declares a variable of type STACKSTR, which may be declared
294 * to be a register. The macro STARTSTACKSTR initializes things. Then
295 * the user uses the macro STPUTC to add characters to the string. In
296 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
297 * grown as necessary. When the user is done, she can just leave the
298 * string there and refer to it using stackblock(). Or she can allocate
299 * the space for it using grabstackstr(). If it is necessary to allow
300 * someone else to use the stack temporarily and then continue to grow
301 * the string, the user should use grabstack to allocate the space, and
302 * then call ungrabstr(p) to return to the previous mode of operation.
304 * USTPUTC is like STPUTC except that it doesn't check for overflow.
305 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
306 * is space for at least one character.
310 growstrstackblock(int n, int min)
313 return stackblock() + n;
321 len = stackblocksize();
322 return (growstrstackblock(len, 0));
327 * Called from CHECKSTRSPACE.
331 makestrspace(int min, char *p)
335 len = p - stackblock();
336 return (growstrstackblock(len, min));
341 stputbin(const char *data, size_t len, char *p)
343 CHECKSTRSPACE(len, p);
344 memcpy(p, data, len);
349 stputs(const char *data, char *p)
351 return (stputbin(data, strlen(data), p));