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/*
Copyright (C) 1988 Free Software Foundation
written by Doug Lea (dl@rocky.oswego.edu)
This file is part of the GNU C++ Library. This library is free
software; you can redistribute it and/or modify it under the terms of
the GNU Library General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your
option) any later version. This library is distributed in the hope
that it will be useful, but WITHOUT ANY WARRANTY; without even the
implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the GNU Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with this library; if not, write to the Free Software
Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifdef __GNUG__
#pragma implementation
#endif
#include <limits.h>
#include <builtin.h>
#include <Obstack.h>
#include <new.h>
/* We use subtraction of (char *)0 instead of casting to int
because on word-addressable machines a simple cast to int
may ignore the byte-within-word field of the pointer. */
#ifndef __PTR_TO_INT
#define __PTR_TO_INT(P) ((P) - (char *)0)
#endif
#ifndef __INT_TO_PTR
#define __INT_TO_PTR(P) ((P) + (char *)0)
#endif
Obstack::Obstack(int size, int alignment)
{
alignmentmask = alignment - 1;
chunksize = size;
chunk = 0;
nextfree = objectbase = 0;
chunklimit = 0;
}
void Obstack::_free(void* obj)
{
_obstack_chunk* lp;
_obstack_chunk* plp;
lp = chunk;
while (lp != 0 && ((void*)lp > obj || (void*)(lp)->limit < obj))
{
plp = lp -> prev;
delete [] (char*)lp;
lp = plp;
}
if (lp)
{
objectbase = nextfree = (char *)(obj);
chunklimit = lp->limit;
chunk = lp;
}
else if (obj != 0)
(*lib_error_handler)("Obstack", "deletion of nonexistent obj");
}
void Obstack::newchunk(int size)
{
_obstack_chunk* old_chunk = chunk;
_obstack_chunk* new_chunk;
long new_size;
int obj_size = nextfree - objectbase;
new_size = (obj_size + size) << 1;
if (new_size < chunksize)
new_size = chunksize;
new_chunk = chunk = new (operator new (new_size)) _obstack_chunk;
new_chunk->prev = old_chunk;
new_chunk->limit = chunklimit = (char *) new_chunk + new_size;
memcpy((void*)new_chunk->contents, (void*)objectbase, obj_size);
objectbase = new_chunk->contents;
nextfree = objectbase + obj_size;
}
void* Obstack::finish()
{
void* value = (void*) objectbase;
nextfree = __INT_TO_PTR (__PTR_TO_INT (nextfree + alignmentmask)
& ~alignmentmask);
if (nextfree - (char*)chunk > chunklimit - (char*)chunk)
nextfree = chunklimit;
objectbase = nextfree;
return value;
}
int Obstack::contains(void* obj) // true if obj somewhere in Obstack
{
_obstack_chunk* ch;
for (ch = chunk;
ch != 0 && (obj < (void*)ch || obj >= (void*)(ch->limit));
ch = ch->prev);
return ch != 0;
}
int Obstack::OK()
{
int v = chunksize > 0; // valid size
v &= alignmentmask != 0; // and alignment
v &= chunk != 0;
v &= objectbase >= chunk->contents;
v &= nextfree >= objectbase;
v &= nextfree <= chunklimit;
v &= chunklimit == chunk->limit;
_obstack_chunk* p = chunk;
// allow lots of chances to find bottom!
long x = LONG_MAX;
while (p != 0 && x != 0) { --x; p = p->prev; }
v &= x > 0;
if (!v)
(*lib_error_handler)("Obstack", "invariant failure");
return v;
}
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