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.
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.
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.
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. */
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
31 #include <stdio.h> /* Random thing to get __GNU_LIBRARY__. */
35 /* Determine default alignment. */
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. */
52 DEFAULT_ALIGNMENT = offsetof (struct fooalign, u),
53 DEFAULT_ROUNDING = sizeof (union fooround)
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. */
61 # define COPYING_UNIT int
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
71 static void print_and_abort (void);
72 void (*obstack_alloc_failed_handler) (void) = print_and_abort;
74 /* Exit value used when `print_and_abort' is used. */
76 int obstack_exit_failure = EXIT_FAILURE;
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. */
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)))
89 # define CALL_FREEFUN(h, old_chunk) \
91 if ((h) -> use_extra_arg) \
92 (*(h)->freefun) ((h)->extra_arg, (old_chunk)); \
94 (*(void (*) (void *)) (h)->freefun) ((old_chunk)); \
98 /* Initialize an obstack H for use. Specify chunk size SIZE (0 means default).
99 Objects start on multiples of ALIGNMENT (0 means use default).
100 CHUNKFUN is the function to use to allocate chunks,
101 and FREEFUN the function to free them.
103 Return nonzero if successful, calls obstack_alloc_failed_handler if
107 _obstack_begin (struct obstack *h,
108 int size, int alignment,
109 void *(*chunkfun) (long),
110 void (*freefun) (void *))
112 register struct _obstack_chunk *chunk; /* points to new chunk */
115 alignment = DEFAULT_ALIGNMENT;
117 /* Default size is what GNU malloc can fit in a 4096-byte block. */
119 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
120 Use the values for range checking, because if range checking is off,
121 the extra bytes won't be missed terribly, but if range checking is on
122 and we used a larger request, a whole extra 4096 bytes would be
125 These number are irrelevant to the new GNU malloc. I suspect it is
126 less sensitive to the size of the request. */
127 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
128 + 4 + DEFAULT_ROUNDING - 1)
129 & ~(DEFAULT_ROUNDING - 1));
133 h->chunkfun = (struct _obstack_chunk * (*)(void *, long)) chunkfun;
134 h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
135 h->chunk_size = size;
136 h->alignment_mask = alignment - 1;
137 h->use_extra_arg = 0;
139 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
141 (*obstack_alloc_failed_handler) ();
142 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
144 h->chunk_limit = chunk->limit
145 = (char *) chunk + h->chunk_size;
147 /* The initial chunk now contains no empty object. */
148 h->maybe_empty_object = 0;
154 _obstack_begin_1 (struct obstack *h, int size, int alignment,
155 void *(*chunkfun) (void *, long),
156 void (*freefun) (void *, void *),
159 register struct _obstack_chunk *chunk; /* points to new chunk */
162 alignment = DEFAULT_ALIGNMENT;
164 /* Default size is what GNU malloc can fit in a 4096-byte block. */
166 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
167 Use the values for range checking, because if range checking is off,
168 the extra bytes won't be missed terribly, but if range checking is on
169 and we used a larger request, a whole extra 4096 bytes would be
172 These number are irrelevant to the new GNU malloc. I suspect it is
173 less sensitive to the size of the request. */
174 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
175 + 4 + DEFAULT_ROUNDING - 1)
176 & ~(DEFAULT_ROUNDING - 1));
180 h->chunkfun = (struct _obstack_chunk * (*)(void *,long)) chunkfun;
181 h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
182 h->chunk_size = size;
183 h->alignment_mask = alignment - 1;
185 h->use_extra_arg = 1;
187 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
189 (*obstack_alloc_failed_handler) ();
190 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
192 h->chunk_limit = chunk->limit
193 = (char *) chunk + h->chunk_size;
195 /* The initial chunk now contains no empty object. */
196 h->maybe_empty_object = 0;
201 /* Allocate a new current chunk for the obstack *H
202 on the assumption that LENGTH bytes need to be added
203 to the current object, or a new object of length LENGTH allocated.
204 Copies any partial object from the end of the old chunk
205 to the beginning of the new one. */
208 _obstack_newchunk (struct obstack *h, int length)
210 register struct _obstack_chunk *old_chunk = h->chunk;
211 register struct _obstack_chunk *new_chunk;
212 register long new_size;
213 register long obj_size = h->next_free - h->object_base;
218 /* Compute size for new chunk. */
219 new_size = (obj_size + length) + (obj_size >> 3) + h->alignment_mask + 100;
220 if (new_size < h->chunk_size)
221 new_size = h->chunk_size;
223 /* Allocate and initialize the new chunk. */
224 new_chunk = CALL_CHUNKFUN (h, new_size);
226 (*obstack_alloc_failed_handler) ();
227 h->chunk = new_chunk;
228 new_chunk->prev = old_chunk;
229 new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size;
231 /* Compute an aligned object_base in the new chunk */
233 __PTR_ALIGN ((char *) new_chunk, new_chunk->contents, h->alignment_mask);
235 /* Move the existing object to the new chunk.
236 Word at a time is fast and is safe if the object
237 is sufficiently aligned. */
238 if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT)
240 for (i = obj_size / sizeof (COPYING_UNIT) - 1;
242 ((COPYING_UNIT *)object_base)[i]
243 = ((COPYING_UNIT *)h->object_base)[i];
244 /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT,
245 but that can cross a page boundary on a machine
246 which does not do strict alignment for COPYING_UNITS. */
247 already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT);
251 /* Copy remaining bytes one by one. */
252 for (i = already; i < obj_size; i++)
253 object_base[i] = h->object_base[i];
255 /* If the object just copied was the only data in OLD_CHUNK,
256 free that chunk and remove it from the chain.
257 But not if that chunk might contain an empty object. */
258 if (! h->maybe_empty_object
260 == __PTR_ALIGN ((char *) old_chunk, old_chunk->contents,
263 new_chunk->prev = old_chunk->prev;
264 CALL_FREEFUN (h, old_chunk);
267 h->object_base = object_base;
268 h->next_free = h->object_base + obj_size;
269 /* The new chunk certainly contains no empty object yet. */
270 h->maybe_empty_object = 0;
273 /* Return nonzero if object OBJ has been allocated from obstack H.
274 This is here for debugging.
275 If you use it in a program, you are probably losing. */
277 /* Suppress -Wmissing-prototypes warning. We don't want to declare this in
278 obstack.h because it is just for debugging. */
279 int _obstack_allocated_p (struct obstack *h, void *obj);
282 _obstack_allocated_p (struct obstack *h, void *obj)
284 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */
285 register struct _obstack_chunk *plp; /* point to previous chunk if any */
288 /* We use >= rather than > since the object cannot be exactly at
289 the beginning of the chunk but might be an empty object exactly
290 at the end of an adjacent chunk. */
291 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
299 /* Free objects in obstack H, including OBJ and everything allocate
300 more recently than OBJ. If OBJ is zero, free everything in H. */
305 obstack_free (struct obstack *h, void *obj)
307 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */
308 register struct _obstack_chunk *plp; /* point to previous chunk if any */
311 /* We use >= because there cannot be an object at the beginning of a chunk.
312 But there can be an empty object at that address
313 at the end of another chunk. */
314 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
317 CALL_FREEFUN (h, lp);
319 /* If we switch chunks, we can't tell whether the new current
320 chunk contains an empty object, so assume that it may. */
321 h->maybe_empty_object = 1;
325 h->object_base = h->next_free = (char *) (obj);
326 h->chunk_limit = lp->limit;
330 /* obj is not in any of the chunks! */
335 _obstack_memory_used (struct obstack *h)
337 register struct _obstack_chunk* lp;
338 register int nbytes = 0;
340 for (lp = h->chunk; lp != 0; lp = lp->prev)
342 nbytes += lp->limit - (char *) lp;
348 __attribute__ ((noreturn))
349 print_and_abort (void)
351 /* Don't change any of these strings. Yes, it would be possible to add
352 the newline to the string and use fputs or so. But this must not
353 happen because the "memory exhausted" message appears in other places
354 like this and the translation should be reused instead of creating
355 a very similar string which requires a separate translation. */
356 fprintf (stderr, "%s\n", "memory exhausted");
357 exit (obstack_exit_failure);