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32 * @(#)memalloc.c 8.3 (Berkeley) 5/4/95
33 * $FreeBSD: head/bin/sh/memalloc.c 250527 2013-05-11 20:51:00Z jilles $
36 #include <sys/param.h>
47 * Like malloc, but returns an error when out of space.
51 ckmalloc(size_t nbytes)
59 error("Out of space");
69 ckrealloc(pointer p, int nbytes)
72 p = realloc(p, nbytes);
75 error("Out of space");
89 * Make a copy of a string in safe storage.
93 savestr(const char *s)
97 p = ckmalloc(strlen(s) + 1);
104 * Parse trees for commands are allocated in lifo order, so we use a stack
105 * to make this more efficient, and also to avoid all sorts of exception
106 * handling code to handle interrupts in the middle of a parse.
108 * The size 496 was chosen because with 16-byte alignment the total size
109 * for the allocated block is 512.
112 #define MINSIZE 496 /* minimum size of a block. */
116 struct stack_block *prev;
119 #define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block)))
121 static struct stack_block *stackp;
128 stnewblock(int nbytes)
130 struct stack_block *sp;
133 if (nbytes < MINSIZE)
136 allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
139 sp = ckmalloc(allocsize);
141 stacknxt = SPACE(sp);
142 stacknleft = allocsize - (stacknxt - (char*)sp);
143 sstrend = stacknxt + stacknleft;
154 nbytes = ALIGN(nbytes);
155 if (nbytes > stacknleft)
159 stacknleft -= nbytes;
167 if (p == NULL) { /*DEBUG */
168 write(STDERR_FILENO, "stunalloc\n", 10);
171 stacknleft += stacknxt - (char *)p;
178 setstackmark(struct stackmark *mark)
180 mark->stackp = stackp;
181 mark->stacknxt = stacknxt;
182 mark->stacknleft = stacknleft;
183 /* Ensure this block stays in place. */
184 if (stackp != NULL && stacknxt == SPACE(stackp))
190 popstackmark(struct stackmark *mark)
192 struct stack_block *sp;
195 while (stackp != mark->stackp) {
200 stacknxt = mark->stacknxt;
201 stacknleft = mark->stacknleft;
202 sstrend = stacknxt + stacknleft;
208 * When the parser reads in a string, it wants to stick the string on the
209 * stack and only adjust the stack pointer when it knows how big the
210 * string is. Stackblock (defined in stack.h) returns a pointer to a block
211 * of space on top of the stack and stackblocklen returns the length of
212 * this block. Growstackblock will grow this space by at least one byte,
213 * possibly moving it (like realloc). Grabstackblock actually allocates the
214 * part of the block that has been used.
218 growstackblock(int min)
224 struct stack_block *sp;
225 struct stack_block *oldstackp;
227 if (min < stacknleft)
229 if ((unsigned int)min >=
230 INT_MAX / 2 - ALIGN(sizeof(struct stack_block)))
231 error("Out of space");
233 min += ALIGN(sizeof(struct stack_block));
240 if (stackp != NULL && stacknxt == SPACE(stackp)) {
243 stackp = oldstackp->prev;
244 sp = ckrealloc((pointer)oldstackp, newlen);
247 stacknxt = SPACE(sp);
248 stacknleft = newlen - (stacknxt - (char*)sp);
249 sstrend = stacknxt + stacknleft;
252 newlen -= ALIGN(sizeof(struct stack_block));
255 memcpy(p, oldspace, oldlen);
263 * The following routines are somewhat easier to use that the above.
264 * The user declares a variable of type STACKSTR, which may be declared
265 * to be a register. The macro STARTSTACKSTR initializes things. Then
266 * the user uses the macro STPUTC to add characters to the string. In
267 * effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
268 * grown as necessary. When the user is done, she can just leave the
269 * string there and refer to it using stackblock(). Or she can allocate
270 * the space for it using grabstackstr(). If it is necessary to allow
271 * someone else to use the stack temporarily and then continue to grow
272 * the string, the user should use grabstack to allocate the space, and
273 * then call ungrabstr(p) to return to the previous mode of operation.
275 * USTPUTC is like STPUTC except that it doesn't check for overflow.
276 * CHECKSTACKSPACE can be called before USTPUTC to ensure that there
277 * is space for at least one character.
281 growstrstackblock(int n, int min)
284 return stackblock() + n;
292 len = stackblocksize();
293 return (growstrstackblock(len, 0));
298 * Called from CHECKSTRSPACE.
302 makestrspace(int min, char *p)
306 len = p - stackblock();
307 return (growstrstackblock(len, min));
312 stputbin(const char *data, size_t len, char *p)
314 CHECKSTRSPACE(len, p);
315 memcpy(p, data, len);
320 stputs(const char *data, char *p)
322 return (stputbin(data, strlen(data), p));