1/* obstack.c - subroutines used implicitly by object stack macros
2 Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1996, 1997, 1998,
3 1999, 2000, 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
19 Boston, MA 02110-1301, USA. */
20#ifdef HAVE_CONFIG_H
21# include <config.h>
22#endif
23
24#include "obstack.h"
25
26/* NOTE BEFORE MODIFYING THIS FILE: This version number must be
27 incremented whenever callers compiled using an old obstack.h can no
28 longer properly call the functions in this obstack.c. */
29#define OBSTACK_INTERFACE_VERSION 1
30
31#include <stdio.h> /* Random thing to get __GNU_LIBRARY__. */
32#include <stddef.h>
33#include <stdint.h>
34
35/* Determine default alignment. */
36union fooround
37{
38 uintmax_t i;
39 long double d;
40 void *p;
41};
42struct fooalign
43{
44 char c;
45 union fooround u;
46};
47/* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT.
48 But in fact it might be less smart and round addresses to as much as
49 DEFAULT_ROUNDING. So we prepare for it to do that. */
50enum
51 {
52 DEFAULT_ALIGNMENT = offsetof (struct fooalign, u),
53 DEFAULT_ROUNDING = sizeof (union fooround)
54 };
55
56/* When we copy a long block of data, this is the unit to do it with.
57 On some machines, copying successive ints does not work;
58 in such a case, redefine COPYING_UNIT to `long' (if that works)
59 or `char' as a last resort. */
60# ifndef COPYING_UNIT
61# define COPYING_UNIT int
62# endif
63
64
65/* The functions allocating more room by calling `obstack_chunk_alloc'
66 jump to the handler pointed to by `obstack_alloc_failed_handler'.
67 This can be set to a user defined function which should either
68 abort gracefully or use longjump - but shouldn't return. This
69 variable by default points to the internal function
70 `print_and_abort'. */
71static void print_and_abort (void);
72void (*obstack_alloc_failed_handler) (void) = print_and_abort;
73
74/* Exit value used when `print_and_abort' is used. */
75# include <stdlib.h>
76int obstack_exit_failure = EXIT_FAILURE;
77
78/* Define a macro that either calls functions with the traditional malloc/free
79 calling interface, or calls functions with the mmalloc/mfree interface
80 (that adds an extra first argument), based on the state of use_extra_arg.
81 For free, do not use ?:, since some compilers, like the MIPS compilers,
82 do not allow (expr) ? void : void. */
83
84# define CALL_CHUNKFUN(h, size) \
85 (((h) -> use_extra_arg) \
86 ? (*(h)->chunkfun) ((h)->extra_arg, (size)) \
87 : (*(struct _obstack_chunk *(*) (long)) (h)->chunkfun) ((size)))
88
89# define CALL_FREEFUN(h, old_chunk) \
90 do { \
91 if ((h) -> use_extra_arg) \
92 (*(h)->freefun) ((h)->extra_arg, (old_chunk)); \
93 else \
94 (*(void (*) (void *)) (h)->freefun) ((old_chunk)); \
95 } while (0)
96
97/* Initialize an obstack H for use. Specify chunk size SIZE (0 means default).
98 Objects start on multiples of ALIGNMENT (0 means use default).
99 CHUNKFUN is the function to use to allocate chunks,
100 and FREEFUN the function to free them.
101
102 Return nonzero if successful, calls obstack_alloc_failed_handler if
103 allocation fails. */
104
105int
106_obstack_begin (struct obstack *h,
107 int size, int alignment,
108 void *(*chunkfun) (long),
109 void (*freefun) (void *))
110{
111 register struct _obstack_chunk *chunk; /* points to new chunk */
112
113 if (alignment == 0)
114 alignment = DEFAULT_ALIGNMENT;
115 if (size == 0)
116 /* Default size is what GNU malloc can fit in a 4096-byte block. */
117 {
118 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
119 Use the values for range checking, because if range checking is off,
120 the extra bytes won't be missed terribly, but if range checking is on
121 and we used a larger request, a whole extra 4096 bytes would be
122 allocated.
123
124 These number are irrelevant to the new GNU malloc. I suspect it is
125 less sensitive to the size of the request. */
126 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
127 + 4 + DEFAULT_ROUNDING - 1)
128 & ~(DEFAULT_ROUNDING - 1));
129 size = 4096 - extra;
130 }
131
132 h->chunkfun = (struct _obstack_chunk * (*)(void *, long)) chunkfun;
133 h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
134 h->chunk_size = size;
135 h->alignment_mask = alignment - 1;
136 h->use_extra_arg = 0;
137
138 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
139 if (!chunk) {
140 (*obstack_alloc_failed_handler) ();
141 return 0;
142 }
143 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
144 alignment - 1);
145 h->chunk_limit = chunk->limit
146 = (char *) chunk + h->chunk_size;
147 chunk->prev = 0;
148 /* The initial chunk now contains no empty object. */
149 h->maybe_empty_object = 0;
150 h->alloc_failed = 0;
151 return 1;
152}
153
154int
155_obstack_begin_1 (struct obstack *h, int size, int alignment,
156 void *(*chunkfun) (void *, long),
157 void (*freefun) (void *, void *),
158 void *arg)
159{
160 register struct _obstack_chunk *chunk; /* points to new chunk */
161
162 if (alignment == 0)
163 alignment = DEFAULT_ALIGNMENT;
164 if (size == 0)
165 /* Default size is what GNU malloc can fit in a 4096-byte block. */
166 {
167 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
168 Use the values for range checking, because if range checking is off,
169 the extra bytes won't be missed terribly, but if range checking is on
170 and we used a larger request, a whole extra 4096 bytes would be
171 allocated.
172
173 These number are irrelevant to the new GNU malloc. I suspect it is
174 less sensitive to the size of the request. */
175 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
176 + 4 + DEFAULT_ROUNDING - 1)
177 & ~(DEFAULT_ROUNDING - 1));
178 size = 4096 - extra;
179 }
180
181 h->chunkfun = (struct _obstack_chunk * (*)(void *,long)) chunkfun;
182 h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
183 h->chunk_size = size;
184 h->alignment_mask = alignment - 1;
185 h->extra_arg = arg;
186 h->use_extra_arg = 1;
187
188 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
189 if (!chunk)
190 (*obstack_alloc_failed_handler) ();
191 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
192 alignment - 1);
193 h->chunk_limit = chunk->limit
194 = (char *) chunk + h->chunk_size;
195 chunk->prev = 0;
196 /* The initial chunk now contains no empty object. */
197 h->maybe_empty_object = 0;
198 h->alloc_failed = 0;
199 return 1;
200}
201
202/* Allocate a new current chunk for the obstack *H
203 on the assumption that LENGTH bytes need to be added
204 to the current object, or a new object of length LENGTH allocated.
205 Copies any partial object from the end of the old chunk
206 to the beginning of the new one. */
207
208void
209_obstack_newchunk (struct obstack *h, int length)
210{
211 register struct _obstack_chunk *old_chunk = h->chunk;
212 register struct _obstack_chunk *new_chunk;
213 register long new_size;
214 register long obj_size = h->next_free - h->object_base;
215 register long i;
216 long already;
217 char *object_base;
218
219 /* Compute size for new chunk. */
220 new_size = (obj_size + length) + (obj_size >> 3) + h->alignment_mask + 100;
221 if (new_size < h->chunk_size)
222 new_size = h->chunk_size;
223
224 /* Allocate and initialize the new chunk. */
225 new_chunk = CALL_CHUNKFUN (h, new_size);
226 if (!new_chunk) {
227 (*obstack_alloc_failed_handler) ();
228 return;
229 }
230 h->chunk = new_chunk;
231 new_chunk->prev = old_chunk;
232 new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size;
233
234 /* Compute an aligned object_base in the new chunk */
235 object_base =
236 __PTR_ALIGN ((char *) new_chunk, new_chunk->contents, h->alignment_mask);
237
238 /* Move the existing object to the new chunk.
239 Word at a time is fast and is safe if the object
240 is sufficiently aligned. */
241 if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT)
242 {
243 for (i = obj_size / sizeof (COPYING_UNIT) - 1;
244 i >= 0; i--)
245 ((COPYING_UNIT *)object_base)[i]
246 = ((COPYING_UNIT *)h->object_base)[i];
247 /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT,
248 but that can cross a page boundary on a machine
249 which does not do strict alignment for COPYING_UNITS. */
250 already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT);
251 }
252 else
253 already = 0;
254 /* Copy remaining bytes one by one. */
255 for (i = already; i < obj_size; i++)
256 object_base[i] = h->object_base[i];
257
258 /* If the object just copied was the only data in OLD_CHUNK,
259 free that chunk and remove it from the chain.
260 But not if that chunk might contain an empty object. */
261 if (! h->maybe_empty_object
262 && (h->object_base
263 == __PTR_ALIGN ((char *) old_chunk, old_chunk->contents,
264 h->alignment_mask)))
265 {
266 new_chunk->prev = old_chunk->prev;
267 CALL_FREEFUN (h, old_chunk);
268 }
269
270 h->object_base = object_base;
271 h->next_free = h->object_base + obj_size;
272 /* The new chunk certainly contains no empty object yet. */
273 h->maybe_empty_object = 0;
274}
275
276/* Return nonzero if object OBJ has been allocated from obstack H.
277 This is here for debugging.
278 If you use it in a program, you are probably losing. */
279
280/* Suppress -Wmissing-prototypes warning. We don't want to declare this in
281 obstack.h because it is just for debugging. */
282int _obstack_allocated_p (struct obstack *h, void *obj);
283
284int
285_obstack_allocated_p (struct obstack *h, void *obj)
286{
287 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */
288 register struct _obstack_chunk *plp; /* point to previous chunk if any */
289
290 lp = (h)->chunk;
291 /* We use >= rather than > since the object cannot be exactly at
292 the beginning of the chunk but might be an empty object exactly
293 at the end of an adjacent chunk. */
294 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
295 {
296 plp = lp->prev;
297 lp = plp;
298 }
299 return lp != 0;
300}
301
302/* Free objects in obstack H, including OBJ and everything allocate
303 more recently than OBJ. If OBJ is zero, free everything in H. */
304
305# undef obstack_free
306
307void
308obstack_free (struct obstack *h, void *obj)
309{
310 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */
311 register struct _obstack_chunk *plp; /* point to previous chunk if any */
312
313 lp = h->chunk;
314 /* We use >= because there cannot be an object at the beginning of a chunk.
315 But there can be an empty object at that address
316 at the end of another chunk. */
317 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
318 {
319 plp = lp->prev;
320 CALL_FREEFUN (h, lp);
321 lp = plp;
322 /* If we switch chunks, we can't tell whether the new current
323 chunk contains an empty object, so assume that it may. */
324 h->maybe_empty_object = 1;
325 }
326 if (lp)
327 {
328 h->object_base = h->next_free = (char *) (obj);
329 h->chunk_limit = lp->limit;
330 h->chunk = lp;
331 }
332 else if (obj != 0)
333 /* obj is not in any of the chunks! */
334 abort ();
335}
336
337int
338_obstack_memory_used (struct obstack *h)
339{
340 register struct _obstack_chunk* lp;
341 register int nbytes = 0;
342
343 for (lp = h->chunk; lp != 0; lp = lp->prev)
344 {
345 nbytes += lp->limit - (char *) lp;
346 }
347 return nbytes;
348}
349
350static void
351#ifndef WIN32
352__attribute__ ((noreturn))
353#endif
354print_and_abort (void)
355{
356 /* Don't change any of these strings. Yes, it would be possible to add
357 the newline to the string and use fputs or so. But this must not
358 happen because the "memory exhausted" message appears in other places
359 like this and the translation should be reused instead of creating
360 a very similar string which requires a separate translation. */
361 fprintf (stderr, "%s\n", "memory exhausted");
362 exit (obstack_exit_failure);
363}
364
365