source: trunk/libs/newlib/src/include/objalloc.h @ 666

Last change on this file since 666 was 444, checked in by satin@…, 6 years ago

add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc

File size: 3.9 KB
Line 
1/* objalloc.h -- routines to allocate memory for objects
2   Copyright (C) 1997-2015 Free Software Foundation, Inc.
3   Written by Ian Lance Taylor, Cygnus Solutions.
4
5This program is free software; you can redistribute it and/or modify it
6under the terms of the GNU General Public License as published by the
7Free Software Foundation; either version 2, or (at your option) any
8later version.
9
10This program is distributed in the hope that it will be useful,
11but WITHOUT ANY WARRANTY; without even the implied warranty of
12MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13GNU General Public License for more details.
14
15You should have received a copy of the GNU General Public License
16along with this program; if not, write to the Free Software
17Foundation, 51 Franklin Street - Fifth Floor,
18Boston, MA 02110-1301, 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
44struct objalloc
45{
46  char *current_ptr;
47  unsigned int current_space;
48  void *chunks;
49};
50
51/* Work out the required alignment.  */
52
53struct objalloc_align { char x; double d; };
54
55#if defined (__STDC__) && __STDC__
56#ifndef offsetof
57#include <stddef.h>
58#endif
59#endif
60#ifndef offsetof
61#define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER)
62#endif
63#define OBJALLOC_ALIGN offsetof (struct objalloc_align, d)
64
65/* Create an objalloc structure.  Returns NULL if malloc fails.  */
66
67extern struct objalloc *objalloc_create (void);
68
69/* Allocate space from an objalloc structure.  Returns NULL if malloc
70   fails.  */
71
72extern void *_objalloc_alloc (struct objalloc *, unsigned long);
73
74/* The macro version of objalloc_alloc.  We only define this if using
75   gcc, because otherwise we would have to evaluate the arguments
76   multiple times, or use a temporary field as obstack.h does.  */
77
78#if defined (__GNUC__) && defined (__STDC__) && __STDC__
79
80/* NextStep 2.0 cc is really gcc 1.93 but it defines __GNUC__ = 2 and
81   does not implement __extension__.  But that compiler doesn't define
82   __GNUC_MINOR__.  */
83#if __GNUC__ < 2 || (__NeXT__ && !__GNUC_MINOR__)
84#define __extension__
85#endif
86
87#define objalloc_alloc(o, l)                                            \
88  __extension__                                                         \
89  ({ struct objalloc *__o = (o);                                        \
90     unsigned long __len = (l);                                         \
91     if (__len == 0)                                                    \
92       __len = 1;                                                       \
93     __len = (__len + OBJALLOC_ALIGN - 1) &~ (OBJALLOC_ALIGN - 1);      \
94     (__len != 0 && __len <= __o->current_space                         \
95      ? (__o->current_ptr += __len,                                     \
96         __o->current_space -= __len,                                   \
97         (void *) (__o->current_ptr - __len))                           \
98      : _objalloc_alloc (__o, __len)); })
99
100#else /* ! __GNUC__ */
101
102#define objalloc_alloc(o, l) _objalloc_alloc ((o), (l))
103
104#endif /* ! __GNUC__ */
105
106/* Free an entire objalloc structure.  */
107
108extern void objalloc_free (struct objalloc *);
109
110/* Free a block allocated by objalloc_alloc.  This also frees all more
111   recently allocated blocks.  */
112
113extern void objalloc_free_block (struct objalloc *, void *);
114
115#endif /* OBJALLOC_H */
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