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. */
24 /* NOTE BEFORE MODIFYING THIS FILE: This version number must be
25 incremented whenever callers compiled using an old obstack.h can no
26 longer properly call the functions in this obstack.c. */
27 #define OBSTACK_INTERFACE_VERSION 1
33 /* Determine default alignment. */
45 /* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT.
46 But in fact it might be less smart and round addresses to as much as
47 DEFAULT_ROUNDING. So we prepare for it to do that. */
50 DEFAULT_ALIGNMENT = offsetof (struct fooalign, u),
51 DEFAULT_ROUNDING = sizeof (union fooround)
54 /* When we copy a long block of data, this is the unit to do it with.
55 On some machines, copying successive ints does not work;
56 in such a case, redefine COPYING_UNIT to `long' (if that works)
57 or `char' as a last resort. */
59 # define COPYING_UNIT int
63 /* The functions allocating more room by calling `obstack_chunk_alloc'
64 jump to the handler pointed to by `obstack_alloc_failed_handler'.
65 This can be set to a user defined function which should either
66 abort gracefully or use longjump - but shouldn't return. This
67 variable by default points to the internal function
69 static void print_and_abort (void);
70 void (*obstack_alloc_failed_handler) (void) = print_and_abort;
72 /* Exit value used when `print_and_abort' is used. */
74 int obstack_exit_failure = EXIT_FAILURE;
76 /* Define a macro that either calls functions with the traditional malloc/free
77 calling interface, or calls functions with the mmalloc/mfree interface
78 (that adds an extra first argument), based on the state of use_extra_arg.
79 For free, do not use ?:, since some compilers, like the MIPS compilers,
80 do not allow (expr) ? void : void. */
82 # define CALL_CHUNKFUN(h, size) \
83 (((h) -> use_extra_arg) \
84 ? (*(h)->chunkfun) ((h)->extra_arg, (size)) \
85 : (*(struct _obstack_chunk *(*) (long)) (h)->chunkfun) ((size)))
87 # define CALL_FREEFUN(h, old_chunk) \
89 if ((h) -> use_extra_arg) \
90 (*(h)->freefun) ((h)->extra_arg, (old_chunk)); \
92 (*(void (*) (void *)) (h)->freefun) ((old_chunk)); \
96 /* Initialize an obstack H for use. Specify chunk size SIZE (0 means default).
97 Objects start on multiples of ALIGNMENT (0 means use default).
98 CHUNKFUN is the function to use to allocate chunks,
99 and FREEFUN the function to free them.
101 Return nonzero if successful, calls obstack_alloc_failed_handler if
104 int _obstack_begin(struct obstack *h, int size, int alignment,
105 void *(*chunkfun)(long), void (*freefun)(void *))
107 register struct _obstack_chunk *chunk; /* points to new chunk */
110 alignment = DEFAULT_ALIGNMENT;
112 /* Default size is what GNU malloc can fit in a 4096-byte block. */
114 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
115 Use the values for range checking, because if range checking is off,
116 the extra bytes won't be missed terribly, but if range checking is on
117 and we used a larger request, a whole extra 4096 bytes would be
120 These number are irrelevant to the new GNU malloc. I suspect it is
121 less sensitive to the size of the request. */
122 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
123 + 4 + DEFAULT_ROUNDING - 1)
124 & ~(DEFAULT_ROUNDING - 1));
128 h->chunkfun = (struct _obstack_chunk * (*)(void *, long)) chunkfun;
129 h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
130 h->chunk_size = size;
131 h->alignment_mask = alignment - 1;
132 h->use_extra_arg = 0;
134 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
136 (*obstack_alloc_failed_handler) ();
137 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
139 h->chunk_limit = chunk->limit
140 = (char *) chunk + h->chunk_size;
142 /* The initial chunk now contains no empty object. */
143 h->maybe_empty_object = 0;
148 int _obstack_begin_1(struct obstack *h, int size, int alignment,
149 void *(*chunkfun) (void *, long),
150 void (*freefun) (void *, void *), void *arg)
152 register struct _obstack_chunk *chunk; /* points to new chunk */
155 alignment = DEFAULT_ALIGNMENT;
157 /* Default size is what GNU malloc can fit in a 4096-byte block. */
159 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
160 Use the values for range checking, because if range checking is off,
161 the extra bytes won't be missed terribly, but if range checking is on
162 and we used a larger request, a whole extra 4096 bytes would be
165 These number are irrelevant to the new GNU malloc. I suspect it is
166 less sensitive to the size of the request. */
167 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
168 + 4 + DEFAULT_ROUNDING - 1)
169 & ~(DEFAULT_ROUNDING - 1));
173 h->chunkfun = (struct _obstack_chunk * (*)(void *,long)) chunkfun;
174 h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
175 h->chunk_size = size;
176 h->alignment_mask = alignment - 1;
178 h->use_extra_arg = 1;
180 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
182 (*obstack_alloc_failed_handler) ();
183 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
185 h->chunk_limit = chunk->limit
186 = (char *) chunk + h->chunk_size;
188 /* The initial chunk now contains no empty object. */
189 h->maybe_empty_object = 0;
194 /* Allocate a new current chunk for the obstack *H
195 on the assumption that LENGTH bytes need to be added
196 to the current object, or a new object of length LENGTH allocated.
197 Copies any partial object from the end of the old chunk
198 to the beginning of the new one. */
200 void _obstack_newchunk(struct obstack *h, int length)
202 register struct _obstack_chunk *old_chunk = h->chunk;
203 register struct _obstack_chunk *new_chunk;
204 register long new_size;
205 register long obj_size = h->next_free - h->object_base;
210 /* Compute size for new chunk. */
211 new_size = (obj_size + length) + (obj_size >> 3) + h->alignment_mask + 100;
212 if (new_size < h->chunk_size)
213 new_size = h->chunk_size;
215 /* Allocate and initialize the new chunk. */
216 new_chunk = CALL_CHUNKFUN (h, new_size);
218 (*obstack_alloc_failed_handler) ();
219 h->chunk = new_chunk;
220 new_chunk->prev = old_chunk;
221 new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size;
223 /* Compute an aligned object_base in the new chunk */
225 __PTR_ALIGN ((char *) new_chunk, new_chunk->contents, h->alignment_mask);
227 /* Move the existing object to the new chunk.
228 Word at a time is fast and is safe if the object
229 is sufficiently aligned. */
230 if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT)
232 for (i = obj_size / sizeof (COPYING_UNIT) - 1;
234 ((COPYING_UNIT *)object_base)[i]
235 = ((COPYING_UNIT *)h->object_base)[i];
236 /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT,
237 but that can cross a page boundary on a machine
238 which does not do strict alignment for COPYING_UNITS. */
239 already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT);
243 /* Copy remaining bytes one by one. */
244 for (i = already; i < obj_size; i++)
245 object_base[i] = h->object_base[i];
247 /* If the object just copied was the only data in OLD_CHUNK,
248 free that chunk and remove it from the chain.
249 But not if that chunk might contain an empty object. */
250 if (! h->maybe_empty_object
252 == __PTR_ALIGN ((char *) old_chunk, old_chunk->contents,
255 new_chunk->prev = old_chunk->prev;
256 CALL_FREEFUN (h, old_chunk);
259 h->object_base = object_base;
260 h->next_free = h->object_base + obj_size;
261 /* The new chunk certainly contains no empty object yet. */
262 h->maybe_empty_object = 0;
265 /* Return nonzero if object OBJ has been allocated from obstack H.
266 This is here for debugging.
267 If you use it in a program, you are probably losing. */
269 /* Suppress -Wmissing-prototypes warning. We don't want to declare this in
270 obstack.h because it is just for debugging. */
271 int _obstack_allocated_p (struct obstack *h, void *obj);
273 int _obstack_allocated_p(struct obstack *h, void *obj)
275 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */
276 register struct _obstack_chunk *plp; /* point to previous chunk if any */
279 /* We use >= rather than > since the object cannot be exactly at
280 the beginning of the chunk but might be an empty object exactly
281 at the end of an adjacent chunk. */
282 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
290 /* Free objects in obstack H, including OBJ and everything allocate
291 more recently than OBJ. If OBJ is zero, free everything in H. */
295 void obstack_free(struct obstack *h, void *obj)
297 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */
298 register struct _obstack_chunk *plp; /* point to previous chunk if any */
301 /* We use >= because there cannot be an object at the beginning of a chunk.
302 But there can be an empty object at that address
303 at the end of another chunk. */
304 while (lp != 0 && ((void *) lp >= obj || (void *) (lp)->limit < obj))
307 CALL_FREEFUN (h, lp);
309 /* If we switch chunks, we can't tell whether the new current
310 chunk contains an empty object, so assume that it may. */
311 h->maybe_empty_object = 1;
315 h->object_base = h->next_free = (char *) (obj);
316 h->chunk_limit = lp->limit;
320 /* obj is not in any of the chunks! */
324 int _obstack_memory_used(struct obstack *h)
326 register struct _obstack_chunk* lp;
327 register int nbytes = 0;
329 for (lp = h->chunk; lp != 0; lp = lp->prev)
331 nbytes += lp->limit - (char *) lp;
336 static void __attribute__((noreturn)) print_and_abort(void)
338 /* Don't change any of these strings. Yes, it would be possible to add
339 the newline to the string and use fputs or so. But this must not
340 happen because the "memory exhausted" message appears in other places
341 like this and the translation should be reused instead of creating
342 a very similar string which requires a separate translation. */
343 fprintf (stderr, "%s\n", "memory exhausted");
344 exit (obstack_exit_failure);