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__. */
34 /* Determine default alignment. */
46 /* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT.
47 But in fact it might be less smart and round addresses to as much as
48 DEFAULT_ROUNDING. So we prepare for it to do that. */
51 DEFAULT_ALIGNMENT = offsetof (struct fooalign, u),
52 DEFAULT_ROUNDING = sizeof (union fooround)
55 /* When we copy a long block of data, this is the unit to do it with.
56 On some machines, copying successive ints does not work;
57 in such a case, redefine COPYING_UNIT to `long' (if that works)
58 or `char' as a last resort. */
60 # define COPYING_UNIT int
64 /* The functions allocating more room by calling `obstack_chunk_alloc'
65 jump to the handler pointed to by `obstack_alloc_failed_handler'.
66 This can be set to a user defined function which should either
67 abort gracefully or use longjump - but shouldn't return. This
68 variable by default points to the internal function
70 static void print_and_abort (void);
71 void (*obstack_alloc_failed_handler) (void) = print_and_abort;
73 /* Exit value used when `print_and_abort' is used. */
75 int obstack_exit_failure = EXIT_FAILURE;
77 /* Define a macro that either calls functions with the traditional malloc/free
78 calling interface, or calls functions with the mmalloc/mfree interface
79 (that adds an extra first argument), based on the state of use_extra_arg.
80 For free, do not use ?:, since some compilers, like the MIPS compilers,
81 do not allow (expr) ? void : void. */
83 # define CALL_CHUNKFUN(h, size) \
84 (((h) -> use_extra_arg) \
85 ? (*(h)->chunkfun) ((h)->extra_arg, (size)) \
86 : (*(struct _obstack_chunk *(*) (long)) (h)->chunkfun) ((size)))
88 # define CALL_FREEFUN(h, old_chunk) \
90 if ((h) -> use_extra_arg) \
91 (*(h)->freefun) ((h)->extra_arg, (old_chunk)); \
93 (*(void (*) (void *)) (h)->freefun) ((old_chunk)); \
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.
102 Return nonzero if successful, calls obstack_alloc_failed_handler if
106 _obstack_begin (struct obstack *h,
107 int size, int alignment,
108 void *(*chunkfun) (long),
109 void (*freefun) (void *))
111 register struct _obstack_chunk *chunk; /* points to new chunk */
114 alignment = DEFAULT_ALIGNMENT;
116 /* Default size is what GNU malloc can fit in a 4096-byte block. */
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
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));
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;
138 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
140 (*obstack_alloc_failed_handler) ();
141 h->next_free = h->object_base = __PTR_ALIGN((char *) chunk, chunk->contents,
143 h->chunk_limit = chunk->limit
144 = (char *) chunk + h->chunk_size;
146 /* The initial chunk now contains no empty object. */
147 h->maybe_empty_object = 0;
153 _obstack_begin_1 (struct obstack *h, int size, int alignment,
154 void *(*chunkfun) (void *, long),
155 void (*freefun) (void *, void *),
158 register struct _obstack_chunk *chunk; /* points to new chunk */
161 alignment = DEFAULT_ALIGNMENT;
163 /* Default size is what GNU malloc can fit in a 4096-byte block. */
165 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
166 Use the values for range checking, because if range checking is off,
167 the extra bytes won't be missed terribly, but if range checking is on
168 and we used a larger request, a whole extra 4096 bytes would be
171 These number are irrelevant to the new GNU malloc. I suspect it is
172 less sensitive to the size of the request. */
173 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
174 + 4 + DEFAULT_ROUNDING - 1)
175 & ~(DEFAULT_ROUNDING - 1));
179 h->chunkfun = (struct _obstack_chunk * (*)(void *,long)) chunkfun;
180 h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
181 h->chunk_size = size;
182 h->alignment_mask = alignment - 1;
184 h->use_extra_arg = 1;
186 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
188 (*obstack_alloc_failed_handler) ();
189 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
191 h->chunk_limit = chunk->limit
192 = (char *) chunk + h->chunk_size;
194 /* The initial chunk now contains no empty object. */
195 h->maybe_empty_object = 0;
200 /* Allocate a new current chunk for the obstack *H
201 on the assumption that LENGTH bytes need to be added
202 to the current object, or a new object of length LENGTH allocated.
203 Copies any partial object from the end of the old chunk
204 to the beginning of the new one. */
207 _obstack_newchunk (struct obstack *h, int length)
209 register struct _obstack_chunk *old_chunk = h->chunk;
210 register struct _obstack_chunk *new_chunk;
211 register long new_size;
212 register long obj_size = h->next_free - h->object_base;
217 /* Compute size for new chunk. */
218 new_size = (obj_size + length) + (obj_size >> 3) + h->alignment_mask + 100;
219 if (new_size < h->chunk_size)
220 new_size = h->chunk_size;
222 /* Allocate and initialize the new chunk. */
223 new_chunk = CALL_CHUNKFUN (h, new_size);
225 (*obstack_alloc_failed_handler) ();
226 h->chunk = new_chunk;
227 new_chunk->prev = old_chunk;
228 new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size;
230 /* Compute an aligned object_base in the new chunk */
232 __PTR_ALIGN ((char *) new_chunk, new_chunk->contents, h->alignment_mask);
234 /* Move the existing object to the new chunk.
235 Word at a time is fast and is safe if the object
236 is sufficiently aligned. */
237 if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT)
239 for (i = obj_size / sizeof (COPYING_UNIT) - 1;
241 ((COPYING_UNIT *)object_base)[i]
242 = ((COPYING_UNIT *)h->object_base)[i];
243 /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT,
244 but that can cross a page boundary on a machine
245 which does not do strict alignment for COPYING_UNITS. */
246 already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT);
250 /* Copy remaining bytes one by one. */
251 for (i = already; i < obj_size; i++)
252 object_base[i] = h->object_base[i];
254 /* If the object just copied was the only data in OLD_CHUNK,
255 free that chunk and remove it from the chain.
256 But not if that chunk might contain an empty object. */
257 if (! h->maybe_empty_object
259 == __PTR_ALIGN ((char *) old_chunk, old_chunk->contents,
262 new_chunk->prev = old_chunk->prev;
263 CALL_FREEFUN (h, old_chunk);
266 h->object_base = object_base;
267 h->next_free = h->object_base + obj_size;
268 /* The new chunk certainly contains no empty object yet. */
269 h->maybe_empty_object = 0;
272 /* Return nonzero if object OBJ has been allocated from obstack H.
273 This is here for debugging.
274 If you use it in a program, you are probably losing. */
276 /* Suppress -Wmissing-prototypes warning. We don't want to declare this in
277 obstack.h because it is just for debugging. */
278 int _obstack_allocated_p (struct obstack *h, void *obj);
281 _obstack_allocated_p (struct obstack *h, void *obj)
283 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */
284 register struct _obstack_chunk *plp; /* point to previous chunk if any */
287 /* We use >= rather than > since the object cannot be exactly at
288 the beginning of the chunk but might be an empty object exactly
289 at the end of an adjacent chunk. */
290 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
298 /* Free objects in obstack H, including OBJ and everything allocate
299 more recently than OBJ. If OBJ is zero, free everything in H. */
304 obstack_free (struct obstack *h, void *obj)
306 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */
307 register struct _obstack_chunk *plp; /* point to previous chunk if any */
310 /* We use >= because there cannot be an object at the beginning of a chunk.
311 But there can be an empty object at that address
312 at the end of another chunk. */
313 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
316 CALL_FREEFUN (h, lp);
318 /* If we switch chunks, we can't tell whether the new current
319 chunk contains an empty object, so assume that it may. */
320 h->maybe_empty_object = 1;
324 h->object_base = h->next_free = (char *) (obj);
325 h->chunk_limit = lp->limit;
329 /* obj is not in any of the chunks! */
334 _obstack_memory_used (struct obstack *h)
336 register struct _obstack_chunk* lp;
337 register int nbytes = 0;
339 for (lp = h->chunk; lp != 0; lp = lp->prev)
341 nbytes += lp->limit - (char *) lp;
347 __attribute__ ((noreturn))
348 print_and_abort (void)
350 /* Don't change any of these strings. Yes, it would be possible to add
351 the newline to the string and use fputs or so. But this must not
352 happen because the "memory exhausted" message appears in other places
353 like this and the translation should be reused instead of creating
354 a very similar string which requires a separate translation. */
355 fprintf (stderr, "%s\n", "memory exhausted");
356 exit (obstack_exit_failure);