1 /* obstack.c - subroutines used implicitly by object stack macros
2 Copyright (C) 1988 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify it
5 under the terms of the GNU General Public License as published by the
6 Free Software Foundation; either version 2, or (at your option) any
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
21 #define POINTER void *
23 #define POINTER char *
26 /* Determine default alignment. */
27 struct fooalign
{char x
; double d
;};
28 #define DEFAULT_ALIGNMENT ((char *)&((struct fooalign *) 0)->d - (char *)0)
29 /* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT.
30 But in fact it might be less smart and round addresses to as much as
31 DEFAULT_ROUNDING. So we prepare for it to do that. */
32 union fooround
{long x
; double d
;};
33 #define DEFAULT_ROUNDING (sizeof (union fooround))
35 /* When we copy a long block of data, this is the unit to do it with.
36 On some machines, copying successive ints does not work;
37 in such a case, redefine COPYING_UNIT to `long' (if that works)
38 or `char' as a last resort. */
40 #define COPYING_UNIT int
43 /* The non-GNU-C macros copy the obstack into this global variable
44 to avoid multiple evaluation. */
46 struct obstack
*_obstack
;
48 /* Initialize an obstack H for use. Specify chunk size SIZE (0 means default).
49 Objects start on multiples of ALIGNMENT (0 means use default).
50 CHUNKFUN is the function to use to allocate chunks,
51 and FREEFUN the function to free them. */
54 _obstack_begin (h
, size
, alignment
, chunkfun
, freefun
)
58 POINTER (*chunkfun
) ();
61 register struct _obstack_chunk
* chunk
; /* points to new chunk */
64 alignment
= DEFAULT_ALIGNMENT
;
66 /* Default size is what GNU malloc can fit in a 4096-byte block. */
68 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
69 Use the values for range checking, because if range checking is off,
70 the extra bytes won't be missed terribly, but if range checking is on
71 and we used a larger request, a whole extra 4096 bytes would be
74 These number are irrelevant to the new GNU malloc. I suspect it is
75 less sensitive to the size of the request. */
76 int extra
= ((((12 + DEFAULT_ROUNDING
- 1) & ~(DEFAULT_ROUNDING
- 1))
77 + 4 + DEFAULT_ROUNDING
- 1)
78 & ~(DEFAULT_ROUNDING
- 1));
82 h
->chunkfun
= (struct _obstack_chunk
* (*)()) chunkfun
;
85 h
->alignment_mask
= alignment
- 1;
87 chunk
= h
->chunk
= (*h
->chunkfun
) (h
->chunk_size
);
88 h
->next_free
= h
->object_base
= chunk
->contents
;
89 h
->chunk_limit
= chunk
->limit
90 = (char *) chunk
+ h
->chunk_size
;
92 /* The initial chunk now contains no empty object. */
93 h
->maybe_empty_object
= 0;
96 /* Allocate a new current chunk for the obstack *H
97 on the assumption that LENGTH bytes need to be added
98 to the current object, or a new object of length LENGTH allocated.
99 Copies any partial object from the end of the old chunk
100 to the beginning of the new one. */
103 _obstack_newchunk (h
, length
)
107 register struct _obstack_chunk
* old_chunk
= h
->chunk
;
108 register struct _obstack_chunk
* new_chunk
;
109 register long new_size
;
110 register int obj_size
= h
->next_free
- h
->object_base
;
114 /* Compute size for new chunk. */
115 new_size
= (obj_size
+ length
) + (obj_size
>> 3) + 100;
116 if (new_size
< h
->chunk_size
)
117 new_size
= h
->chunk_size
;
119 /* Allocate and initialize the new chunk. */
120 new_chunk
= h
->chunk
= (*h
->chunkfun
) (new_size
);
121 new_chunk
->prev
= old_chunk
;
122 new_chunk
->limit
= h
->chunk_limit
= (char *) new_chunk
+ new_size
;
124 /* Move the existing object to the new chunk.
125 Word at a time is fast and is safe if the object
126 is sufficiently aligned. */
127 if (h
->alignment_mask
+ 1 >= DEFAULT_ALIGNMENT
)
129 for (i
= obj_size
/ sizeof (COPYING_UNIT
) - 1;
131 ((COPYING_UNIT
*)new_chunk
->contents
)[i
]
132 = ((COPYING_UNIT
*)h
->object_base
)[i
];
133 /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT,
134 but that can cross a page boundary on a machine
135 which does not do strict alignment for COPYING_UNITS. */
136 already
= obj_size
/ sizeof (COPYING_UNIT
) * sizeof (COPYING_UNIT
);
140 /* Copy remaining bytes one by one. */
141 for (i
= already
; i
< obj_size
; i
++)
142 new_chunk
->contents
[i
] = h
->object_base
[i
];
144 /* If the object just copied was the only data in OLD_CHUNK,
145 free that chunk and remove it from the chain.
146 But not if that chunk might contain an empty object. */
147 if (h
->object_base
== old_chunk
->contents
&& ! h
->maybe_empty_object
)
149 new_chunk
->prev
= old_chunk
->prev
;
150 (*h
->freefun
) (old_chunk
);
153 h
->object_base
= new_chunk
->contents
;
154 h
->next_free
= h
->object_base
+ obj_size
;
155 /* The new chunk certainly contains no empty object yet. */
156 h
->maybe_empty_object
= 0;
159 /* Return nonzero if object OBJ has been allocated from obstack H.
160 This is here for debugging.
161 If you use it in a program, you are probably losing. */
164 _obstack_allocated_p (h
, obj
)
168 register struct _obstack_chunk
* lp
; /* below addr of any objects in this chunk */
169 register struct _obstack_chunk
* plp
; /* point to previous chunk if any */
172 /* We use >= rather than > since the object cannot be exactly at
173 the beginning of the chunk but might be an empty object exactly
174 at the end of an adjacent chunk. */
175 while (lp
!= 0 && ((POINTER
)lp
>= obj
|| (POINTER
)(lp
)->limit
< obj
))
183 /* Free objects in obstack H, including OBJ and everything allocate
184 more recently than OBJ. If OBJ is zero, free everything in H. */
188 /* This function has two names with identical definitions.
189 This is the first one, called from non-ANSI code. */
192 _obstack_free (h
, obj
)
196 register struct _obstack_chunk
* lp
; /* below addr of any objects in this chunk */
197 register struct _obstack_chunk
* plp
; /* point to previous chunk if any */
200 /* We use >= because there cannot be an object at the beginning of a chunk.
201 But there can be an empty object at that address
202 at the end of another chunk. */
203 while (lp
!= 0 && ((POINTER
)lp
>= obj
|| (POINTER
)(lp
)->limit
< obj
))
208 /* If we switch chunks, we can't tell whether the new current
209 chunk contains an empty object, so assume that it may. */
210 h
->maybe_empty_object
= 1;
214 h
->object_base
= h
->next_free
= (char *)(obj
);
215 h
->chunk_limit
= lp
->limit
;
219 /* obj is not in any of the chunks! */
223 /* This function is used from ANSI code. */
226 obstack_free (h
, obj
)
230 register struct _obstack_chunk
* lp
; /* below addr of any objects in this chunk */
231 register struct _obstack_chunk
* plp
; /* point to previous chunk if any */
234 /* We use >= because there cannot be an object at the beginning of a chunk.
235 But there can be an empty object at that address
236 at the end of another chunk. */
237 while (lp
!= 0 && ((POINTER
)lp
>= obj
|| (POINTER
)(lp
)->limit
< obj
))
242 /* If we switch chunks, we can't tell whether the new current
243 chunk contains an empty object, so assume that it may. */
244 h
->maybe_empty_object
= 1;
248 h
->object_base
= h
->next_free
= (char *)(obj
);
249 h
->chunk_limit
= lp
->limit
;
253 /* obj is not in any of the chunks! */
258 /* These are now turned off because the applications do not use it
259 and it uses bcopy via obstack_grow, which causes trouble on sysV. */
261 /* Now define the functional versions of the obstack macros.
262 Define them to simply use the corresponding macros to do the job. */
265 /* These function definitions do not work with non-ANSI preprocessors;
266 they won't pass through the macro names in parentheses. */
268 /* The function names appear in parentheses in order to prevent
269 the macro-definitions of the names from being expanded there. */
271 POINTER (obstack_base
) (obstack
)
272 struct obstack
*obstack
;
274 return obstack_base (obstack
);
277 POINTER (obstack_next_free
) (obstack
)
278 struct obstack
*obstack
;
280 return obstack_next_free (obstack
);
283 int (obstack_object_size
) (obstack
)
284 struct obstack
*obstack
;
286 return obstack_object_size (obstack
);
289 int (obstack_room
) (obstack
)
290 struct obstack
*obstack
;
292 return obstack_room (obstack
);
295 void (obstack_grow
) (obstack
, pointer
, length
)
296 struct obstack
*obstack
;
300 obstack_grow (obstack
, pointer
, length
);
303 void (obstack_grow0
) (obstack
, pointer
, length
)
304 struct obstack
*obstack
;
308 obstack_grow0 (obstack
, pointer
, length
);
311 void (obstack_1grow
) (obstack
, character
)
312 struct obstack
*obstack
;
315 obstack_1grow (obstack
, character
);
318 void (obstack_blank
) (obstack
, length
)
319 struct obstack
*obstack
;
322 obstack_blank (obstack
, length
);
325 void (obstack_1grow_fast
) (obstack
, character
)
326 struct obstack
*obstack
;
329 obstack_1grow_fast (obstack
, character
);
332 void (obstack_blank_fast
) (obstack
, length
)
333 struct obstack
*obstack
;
336 obstack_blank_fast (obstack
, length
);
339 POINTER (obstack_finish
) (obstack
)
340 struct obstack
*obstack
;
342 return obstack_finish (obstack
);
345 POINTER (obstack_alloc
) (obstack
, length
)
346 struct obstack
*obstack
;
349 return obstack_alloc (obstack
, length
);
352 POINTER (obstack_copy
) (obstack
, pointer
, length
)
353 struct obstack
*obstack
;
357 return obstack_copy (obstack
, pointer
, length
);
360 POINTER (obstack_copy0
) (obstack
, pointer
, length
)
361 struct obstack
*obstack
;
365 return obstack_copy0 (obstack
, pointer
, length
);
368 #endif /* __STDC__ */
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