0402932766
immediately written into the stack after the call. Instead let the caller
manage the "space left".
Previously, growstackstr()'s assumption causes problems with STACKSTRNUL()
where we want to be able to turn a stack into a C string, and later
pretend the NUL is not there.
This fixes a bug in STACKSTRNUL() (that grew the stack) where:
1. STADJUST() called after a STACKSTRNUL() results in an improper adjust.
This can be seen in ${var%pattern} and ${var%%pattern} evaluation.
2. Memory leak in STPUTC() called after a STACKSTRNUL().
Reviewed by: jilles
343 lines
7.4 KiB
C
343 lines
7.4 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Kenneth Almquist.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)memalloc.c 8.3 (Berkeley) 5/4/95";
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#endif
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#endif /* not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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#include "shell.h"
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#include "output.h"
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#include "memalloc.h"
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#include "error.h"
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#include "mystring.h"
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#include "expand.h"
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#include <stdlib.h>
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#include <unistd.h>
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/*
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* Like malloc, but returns an error when out of space.
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*/
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pointer
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ckmalloc(size_t nbytes)
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{
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pointer p;
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INTOFF;
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p = malloc(nbytes);
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INTON;
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if (p == NULL)
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error("Out of space");
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return p;
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}
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/*
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* Same for realloc.
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*/
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pointer
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ckrealloc(pointer p, int nbytes)
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{
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INTOFF;
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p = realloc(p, nbytes);
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INTON;
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if (p == NULL)
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error("Out of space");
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return p;
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}
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void
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ckfree(pointer p)
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{
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INTOFF;
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free(p);
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INTON;
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}
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/*
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* Make a copy of a string in safe storage.
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*/
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char *
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savestr(const char *s)
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{
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char *p;
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p = ckmalloc(strlen(s) + 1);
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scopy(s, p);
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return p;
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}
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/*
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* Parse trees for commands are allocated in lifo order, so we use a stack
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* to make this more efficient, and also to avoid all sorts of exception
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* handling code to handle interrupts in the middle of a parse.
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*
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* The size 496 was chosen because with 16-byte alignment the total size
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* for the allocated block is 512.
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*/
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#define MINSIZE 496 /* minimum size of a block. */
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struct stack_block {
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struct stack_block *prev;
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/* Data follows */
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};
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#define SPACE(sp) ((char*)(sp) + ALIGN(sizeof(struct stack_block)))
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static struct stack_block *stackp;
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static struct stackmark *markp;
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char *stacknxt;
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int stacknleft;
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int sstrnleft;
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int herefd = -1;
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static void
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stnewblock(int nbytes)
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{
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struct stack_block *sp;
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int allocsize;
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if (nbytes < MINSIZE)
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nbytes = MINSIZE;
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allocsize = ALIGN(sizeof(struct stack_block)) + ALIGN(nbytes);
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INTOFF;
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sp = ckmalloc(allocsize);
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sp->prev = stackp;
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stacknxt = SPACE(sp);
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stacknleft = allocsize - (stacknxt - (char*)sp);
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stackp = sp;
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INTON;
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}
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pointer
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stalloc(int nbytes)
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{
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char *p;
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nbytes = ALIGN(nbytes);
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if (nbytes > stacknleft)
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stnewblock(nbytes);
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p = stacknxt;
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stacknxt += nbytes;
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stacknleft -= nbytes;
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return p;
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}
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void
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stunalloc(pointer p)
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{
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if (p == NULL) { /*DEBUG */
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write(STDERR_FILENO, "stunalloc\n", 10);
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abort();
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}
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stacknleft += stacknxt - (char *)p;
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stacknxt = p;
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}
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void
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setstackmark(struct stackmark *mark)
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{
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mark->stackp = stackp;
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mark->stacknxt = stacknxt;
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mark->stacknleft = stacknleft;
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mark->marknext = markp;
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markp = mark;
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}
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void
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popstackmark(struct stackmark *mark)
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{
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struct stack_block *sp;
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INTOFF;
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markp = mark->marknext;
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while (stackp != mark->stackp) {
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sp = stackp;
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stackp = sp->prev;
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ckfree(sp);
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}
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stacknxt = mark->stacknxt;
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stacknleft = mark->stacknleft;
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INTON;
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}
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/*
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* When the parser reads in a string, it wants to stick the string on the
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* stack and only adjust the stack pointer when it knows how big the
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* string is. Stackblock (defined in stack.h) returns a pointer to a block
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* of space on top of the stack and stackblocklen returns the length of
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* this block. Growstackblock will grow this space by at least one byte,
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* possibly moving it (like realloc). Grabstackblock actually allocates the
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* part of the block that has been used.
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*/
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void
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growstackblock(void)
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{
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char *p;
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int newlen;
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char *oldspace;
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int oldlen;
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struct stack_block *sp;
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struct stack_block *oldstackp;
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struct stackmark *xmark;
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newlen = (stacknleft == 0) ? MINSIZE : stacknleft * 2 + 100;
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newlen = ALIGN(newlen);
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oldspace = stacknxt;
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oldlen = stacknleft;
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if (stackp != NULL && stacknxt == SPACE(stackp)) {
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INTOFF;
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oldstackp = stackp;
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stackp = oldstackp->prev;
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sp = ckrealloc((pointer)oldstackp, newlen);
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sp->prev = stackp;
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stackp = sp;
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stacknxt = SPACE(sp);
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stacknleft = newlen - (stacknxt - (char*)sp);
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/*
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* Stack marks pointing to the start of the old block
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* must be relocated to point to the new block
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*/
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xmark = markp;
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while (xmark != NULL && xmark->stackp == oldstackp) {
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xmark->stackp = stackp;
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xmark->stacknxt = stacknxt;
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xmark->stacknleft = stacknleft;
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xmark = xmark->marknext;
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}
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INTON;
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} else {
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p = stalloc(newlen);
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if (oldlen != 0)
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memcpy(p, oldspace, oldlen);
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stunalloc(p);
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}
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}
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void
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grabstackblock(int len)
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{
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len = ALIGN(len);
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stacknxt += len;
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stacknleft -= len;
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}
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/*
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* The following routines are somewhat easier to use that the above.
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* The user declares a variable of type STACKSTR, which may be declared
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* to be a register. The macro STARTSTACKSTR initializes things. Then
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* the user uses the macro STPUTC to add characters to the string. In
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* effect, STPUTC(c, p) is the same as *p++ = c except that the stack is
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* grown as necessary. When the user is done, she can just leave the
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* string there and refer to it using stackblock(). Or she can allocate
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* the space for it using grabstackstr(). If it is necessary to allow
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* someone else to use the stack temporarily and then continue to grow
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* the string, the user should use grabstack to allocate the space, and
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* then call ungrabstr(p) to return to the previous mode of operation.
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*
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* USTPUTC is like STPUTC except that it doesn't check for overflow.
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* CHECKSTACKSPACE can be called before USTPUTC to ensure that there
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* is space for at least one character.
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*/
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static char *
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growstrstackblock(int n)
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{
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growstackblock();
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sstrnleft = stackblocksize() - n;
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return stackblock() + n;
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}
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char *
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growstackstr(void)
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{
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int len;
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len = stackblocksize();
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if (herefd >= 0 && len >= 1024) {
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xwrite(herefd, stackblock(), len);
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sstrnleft = len;
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return stackblock();
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}
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return growstrstackblock(len);
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}
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/*
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* Called from CHECKSTRSPACE.
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*/
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char *
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makestrspace(void)
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{
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int len;
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len = stackblocksize() - sstrnleft;
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return growstrstackblock(len);
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}
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void
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ungrabstackstr(char *s, char *p)
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{
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stacknleft += stacknxt - s;
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stacknxt = s;
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sstrnleft = stacknleft - (p - s);
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}
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