116 lines
3.9 KiB
C
116 lines
3.9 KiB
C
/* objalloc.h -- routines to allocate memory for objects
|
|
Copyright (C) 1997-2018 Free Software Foundation, Inc.
|
|
Written by Ian Lance Taylor, Cygnus Solutions.
|
|
|
|
This program is free software; you can redistribute it and/or modify it
|
|
under the terms of the GNU General Public License as published by the
|
|
Free Software Foundation; either version 2, or (at your option) any
|
|
later version.
|
|
|
|
This program 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 General Public License for more details.
|
|
|
|
You should have received a copy of the GNU General Public License
|
|
along with this program; if not, write to the Free Software
|
|
Foundation, 51 Franklin Street - Fifth Floor,
|
|
Boston, MA 02110-1301, USA. */
|
|
|
|
#ifndef OBJALLOC_H
|
|
#define OBJALLOC_H
|
|
|
|
#include "ansidecl.h"
|
|
|
|
/* These routines allocate space for an object. The assumption is
|
|
that the object will want to allocate space as it goes along, but
|
|
will never want to free any particular block. There is a function
|
|
to free a block, which also frees all more recently allocated
|
|
blocks. There is also a function to free all the allocated space.
|
|
|
|
This is essentially a specialization of obstacks. The main
|
|
difference is that a block may not be allocated a bit at a time.
|
|
Another difference is that these routines are always built on top
|
|
of malloc, and always pass an malloc failure back to the caller,
|
|
unlike more recent versions of obstacks. */
|
|
|
|
/* This is what an objalloc structure looks like. Callers should not
|
|
refer to these fields, nor should they allocate these structure
|
|
themselves. Instead, they should only create them via
|
|
objalloc_init, and only access them via the functions and macros
|
|
listed below. The structure is only defined here so that we can
|
|
access it via macros. */
|
|
|
|
struct objalloc
|
|
{
|
|
char *current_ptr;
|
|
unsigned int current_space;
|
|
void *chunks;
|
|
};
|
|
|
|
/* Work out the required alignment. */
|
|
|
|
struct objalloc_align { char x; double d; };
|
|
|
|
#if defined (__STDC__) && __STDC__
|
|
#ifndef offsetof
|
|
#include <stddef.h>
|
|
#endif
|
|
#endif
|
|
#ifndef offsetof
|
|
#define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
|
|
#endif
|
|
#define OBJALLOC_ALIGN offsetof (struct objalloc_align, d)
|
|
|
|
/* Create an objalloc structure. Returns NULL if malloc fails. */
|
|
|
|
extern struct objalloc *objalloc_create (void);
|
|
|
|
/* Allocate space from an objalloc structure. Returns NULL if malloc
|
|
fails. */
|
|
|
|
extern void *_objalloc_alloc (struct objalloc *, unsigned long);
|
|
|
|
/* The macro version of objalloc_alloc. We only define this if using
|
|
gcc, because otherwise we would have to evaluate the arguments
|
|
multiple times, or use a temporary field as obstack.h does. */
|
|
|
|
#if defined (__GNUC__) && defined (__STDC__) && __STDC__
|
|
|
|
/* NextStep 2.0 cc is really gcc 1.93 but it defines __GNUC__ = 2 and
|
|
does not implement __extension__. But that compiler doesn't define
|
|
__GNUC_MINOR__. */
|
|
#if __GNUC__ < 2 || (__NeXT__ && !__GNUC_MINOR__)
|
|
#define __extension__
|
|
#endif
|
|
|
|
#define objalloc_alloc(o, l) \
|
|
__extension__ \
|
|
({ struct objalloc *__o = (o); \
|
|
unsigned long __len = (l); \
|
|
if (__len == 0) \
|
|
__len = 1; \
|
|
__len = (__len + OBJALLOC_ALIGN - 1) &~ (OBJALLOC_ALIGN - 1); \
|
|
(__len != 0 && __len <= __o->current_space \
|
|
? (__o->current_ptr += __len, \
|
|
__o->current_space -= __len, \
|
|
(void *) (__o->current_ptr - __len)) \
|
|
: _objalloc_alloc (__o, __len)); })
|
|
|
|
#else /* ! __GNUC__ */
|
|
|
|
#define objalloc_alloc(o, l) _objalloc_alloc ((o), (l))
|
|
|
|
#endif /* ! __GNUC__ */
|
|
|
|
/* Free an entire objalloc structure. */
|
|
|
|
extern void objalloc_free (struct objalloc *);
|
|
|
|
/* Free a block allocated by objalloc_alloc. This also frees all more
|
|
recently allocated blocks. */
|
|
|
|
extern void objalloc_free_block (struct objalloc *, void *);
|
|
|
|
#endif /* OBJALLOC_H */
|