[binutils.git] / include / objalloc.h

/* objalloc.h -- routines to allocate memory for objects
   Copyright 1997 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, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, 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;
  PTR chunks;
};

/* Work out the required alignment.  */

struct objalloc_align { char x; double d; };

#if defined (__STDC__) && __STDC__
#ifndef offsetof
#include <stddef.h>
#endif
#define OBJALLOC_ALIGN \
  ((ptrdiff_t) ((char *) &((struct objalloc_align *) 0)->d - (char *) 0))
#else
#define OBJALLOC_ALIGN \
  ((long) ((char *) &((struct objalloc_align *) 0)->d - (char *) 0))
#endif

/* Create an objalloc structure.  Returns NULL if malloc fails.  */

extern struct objalloc *objalloc_create PARAMS ((void));

/* Allocate space from an objalloc structure.  Returns NULL if malloc
   fails.  */

extern PTR _objalloc_alloc PARAMS ((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 <= __o->current_space					\
      ? (__o->current_ptr += __len,					\
	 __o->current_space -= __len,					\
	 (PTR) (__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 PARAMS ((struct objalloc *));

/* Free a block allocated by objalloc_alloc.  This also frees all more
   recently allocated blocks.  */

extern void objalloc_free_block PARAMS ((struct objalloc *, PTR));

#endif /* OBJALLOC_H */
Commit	Line	Data
252b5132 RH	1	/* objalloc.h -- routines to allocate memory for objects
	2	Copyright 1997 Free Software Foundation, Inc.
	3	Written by Ian Lance Taylor, Cygnus Solutions.
	4
	5	This program is free software; you can redistribute it and/or modify it
	6	under the terms of the GNU General Public License as published by the
	7	Free Software Foundation; either version 2, or (at your option) any
	8	later version.
	9
	10	This program is distributed in the hope that it will be useful,
	11	but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	GNU General Public License for more details.
	14
	15	You should have received a copy of the GNU General Public License
	16	along with this program; if not, write to the Free Software
	17	Foundation, 59 Temple Place - Suite 330,
	18	Boston, MA 02111-1307, USA. */
	19
	20	#ifndef OBJALLOC_H
	21	#define OBJALLOC_H
	22
	23	#include "ansidecl.h"
	24
	25	/* These routines allocate space for an object. The assumption is
	26	that the object will want to allocate space as it goes along, but
	27	will never want to free any particular block. There is a function
	28	to free a block, which also frees all more recently allocated
	29	blocks. There is also a function to free all the allocated space.
	30
	31	This is essentially a specialization of obstacks. The main
	32	difference is that a block may not be allocated a bit at a time.
	33	Another difference is that these routines are always built on top
	34	of malloc, and always pass an malloc failure back to the caller,
	35	unlike more recent versions of obstacks. */
	36
	37	/* This is what an objalloc structure looks like. Callers should not
	38	refer to these fields, nor should they allocate these structure
	39	themselves. Instead, they should only create them via
	40	objalloc_init, and only access them via the functions and macros
	41	listed below. The structure is only defined here so that we can
	42	access it via macros. */
	43
	44	struct objalloc
	45	{
	46	char *current_ptr;
	47	unsigned int current_space;
	48	PTR chunks;
	49	};
	50
	51	/* Work out the required alignment. */
	52
	53	struct objalloc_align { char x; double d; };
	54
	55	#if defined (__STDC__) && __STDC__
	56	#ifndef offsetof
	57	#include <stddef.h>
	58	#endif
	59	#define OBJALLOC_ALIGN \
	60	((ptrdiff_t) ((char ) &((struct objalloc_align ) 0)->d - (char *) 0))
	61	#else
	62	#define OBJALLOC_ALIGN \
	63	((long) ((char ) &((struct objalloc_align ) 0)->d - (char *) 0))
	64	#endif
65
66	/* Create an objalloc structure. Returns NULL if malloc fails. */
67
68	extern struct objalloc *objalloc_create PARAMS ((void));
69
70	/* Allocate space from an objalloc structure. Returns NULL if malloc
71	fails. */
72
73	extern PTR _objalloc_alloc PARAMS ((struct objalloc *, unsigned long));
74
75	/* The macro version of objalloc_alloc. We only define this if using
76	gcc, because otherwise we would have to evaluate the arguments
77	multiple times, or use a temporary field as obstack.h does. */
78
79	#if defined (__GNUC__) && defined (__STDC__) && __STDC__
80
81	/* NextStep 2.0 cc is really gcc 1.93 but it defines __GNUC__ = 2 and
82	does not implement __extension__. But that compiler doesn't define
83	__GNUC_MINOR__. */
84	#if __GNUC__ < 2 \|\| (__NeXT__ && !__GNUC_MINOR__)
85	#define __extension__
86	#endif
87
88	#define objalloc_alloc(o, l) \
89	__extension__ \
90	({ struct objalloc *__o = (o); \
91	unsigned long __len = (l); \
92	if (__len == 0) \
93	__len = 1; \
94	__len = (__len + OBJALLOC_ALIGN - 1) &~ (OBJALLOC_ALIGN - 1); \
95	(__len <= __o->current_space \
96	? (__o->current_ptr += __len, \
97	__o->current_space -= __len, \
98	(PTR) (__o->current_ptr - __len)) \
99	: _objalloc_alloc (__o, __len)); })
100
101	#else /* ! __GNUC__ */
102
103	#define objalloc_alloc(o, l) _objalloc_alloc ((o), (l))
104
105	#endif /* ! __GNUC__ */
106
107	/* Free an entire objalloc structure. */
108
109	extern void objalloc_free PARAMS ((struct objalloc *));
110
111	/* Free a block allocated by objalloc_alloc. This also frees all more
112	recently allocated blocks. */
113
114	extern void objalloc_free_block PARAMS ((struct objalloc *, PTR));
115
116	#endif /* OBJALLOC_H */