rebase --root: fix amending root commit messages
[git.git] / compat / obstack.c
blob4d1d95beeb509b3bb159b4eaadf20deeb498e73a
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, see
18 <http://www.gnu.org/licenses/>. */
20 #include "git-compat-util.h"
21 #include <gettext.h>
22 #include "obstack.h"
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
29 /* Comment out all this code if we are using the GNU C Library, and are not
30 actually compiling the library itself, and the installed library
31 supports the same library interface we do. This code is part of the GNU
32 C Library, but also included in many other GNU distributions. Compiling
33 and linking in this code is a waste when using the GNU C library
34 (especially if it is a shared library). Rather than having every GNU
35 program understand `configure --with-gnu-libc' and omit the object
36 files, it is simpler to just do this in the source for each such file. */
38 #include <stdio.h> /* Random thing to get __GNU_LIBRARY__. */
39 #if !defined _LIBC && defined __GNU_LIBRARY__ && __GNU_LIBRARY__ > 1
40 # include <gnu-versions.h>
41 # if _GNU_OBSTACK_INTERFACE_VERSION == OBSTACK_INTERFACE_VERSION
42 # define ELIDE_CODE
43 # endif
44 #endif
46 #include <stddef.h>
48 #ifndef ELIDE_CODE
51 # if HAVE_INTTYPES_H
52 # include <inttypes.h>
53 # endif
54 # if HAVE_STDINT_H || defined _LIBC
55 # include <stdint.h>
56 # endif
58 /* Determine default alignment. */
59 union fooround
61 uintmax_t i;
62 long double d;
63 void *p;
65 struct fooalign
67 char c;
68 union fooround u;
70 /* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT.
71 But in fact it might be less smart and round addresses to as much as
72 DEFAULT_ROUNDING. So we prepare for it to do that. */
73 enum
75 DEFAULT_ALIGNMENT = offsetof (struct fooalign, u),
76 DEFAULT_ROUNDING = sizeof (union fooround)
79 /* When we copy a long block of data, this is the unit to do it with.
80 On some machines, copying successive ints does not work;
81 in such a case, redefine COPYING_UNIT to `long' (if that works)
82 or `char' as a last resort. */
83 # ifndef COPYING_UNIT
84 # define COPYING_UNIT int
85 # endif
88 /* The functions allocating more room by calling `obstack_chunk_alloc'
89 jump to the handler pointed to by `obstack_alloc_failed_handler'.
90 This can be set to a user defined function which should either
91 abort gracefully or use longjump - but shouldn't return. This
92 variable by default points to the internal function
93 `print_and_abort'. */
94 static void print_and_abort (void);
95 void (*obstack_alloc_failed_handler) (void) = print_and_abort;
97 # ifdef _LIBC
98 # if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_3_4)
99 /* A looong time ago (before 1994, anyway; we're not sure) this global variable
100 was used by non-GNU-C macros to avoid multiple evaluation. The GNU C
101 library still exports it because somebody might use it. */
102 struct obstack *_obstack_compat;
103 compat_symbol (libc, _obstack_compat, _obstack, GLIBC_2_0);
104 # endif
105 # endif
107 /* Define a macro that either calls functions with the traditional malloc/free
108 calling interface, or calls functions with the mmalloc/mfree interface
109 (that adds an extra first argument), based on the state of use_extra_arg.
110 For free, do not use ?:, since some compilers, like the MIPS compilers,
111 do not allow (expr) ? void : void. */
113 # define CALL_CHUNKFUN(h, size) \
114 (((h) -> use_extra_arg) \
115 ? (*(h)->chunkfun) ((h)->extra_arg, (size)) \
116 : (*(struct _obstack_chunk *(*) (long)) (h)->chunkfun) ((size)))
118 # define CALL_FREEFUN(h, old_chunk) \
119 do { \
120 if ((h) -> use_extra_arg) \
121 (*(h)->freefun) ((h)->extra_arg, (old_chunk)); \
122 else \
123 (*(void (*) (void *)) (h)->freefun) ((old_chunk)); \
124 } while (0)
127 /* Initialize an obstack H for use. Specify chunk size SIZE (0 means default).
128 Objects start on multiples of ALIGNMENT (0 means use default).
129 CHUNKFUN is the function to use to allocate chunks,
130 and FREEFUN the function to free them.
132 Return nonzero if successful, calls obstack_alloc_failed_handler if
133 allocation fails. */
136 _obstack_begin (struct obstack *h,
137 int size, int alignment,
138 void *(*chunkfun) (long),
139 void (*freefun) (void *))
141 register struct _obstack_chunk *chunk; /* points to new chunk */
143 if (alignment == 0)
144 alignment = DEFAULT_ALIGNMENT;
145 if (size == 0)
146 /* Default size is what GNU malloc can fit in a 4096-byte block. */
148 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
149 Use the values for range checking, because if range checking is off,
150 the extra bytes won't be missed terribly, but if range checking is on
151 and we used a larger request, a whole extra 4096 bytes would be
152 allocated.
154 These number are irrelevant to the new GNU malloc. I suspect it is
155 less sensitive to the size of the request. */
156 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
157 + 4 + DEFAULT_ROUNDING - 1)
158 & ~(DEFAULT_ROUNDING - 1));
159 size = 4096 - extra;
162 h->chunkfun = (struct _obstack_chunk * (*)(void *, long)) chunkfun;
163 h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
164 h->chunk_size = size;
165 h->alignment_mask = alignment - 1;
166 h->use_extra_arg = 0;
168 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
169 if (!chunk)
170 (*obstack_alloc_failed_handler) ();
171 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
172 alignment - 1);
173 h->chunk_limit = chunk->limit
174 = (char *) chunk + h->chunk_size;
175 chunk->prev = NULL;
176 /* The initial chunk now contains no empty object. */
177 h->maybe_empty_object = 0;
178 h->alloc_failed = 0;
179 return 1;
183 _obstack_begin_1 (struct obstack *h, int size, int alignment,
184 void *(*chunkfun) (void *, long),
185 void (*freefun) (void *, void *),
186 void *arg)
188 register struct _obstack_chunk *chunk; /* points to new chunk */
190 if (alignment == 0)
191 alignment = DEFAULT_ALIGNMENT;
192 if (size == 0)
193 /* Default size is what GNU malloc can fit in a 4096-byte block. */
195 /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc.
196 Use the values for range checking, because if range checking is off,
197 the extra bytes won't be missed terribly, but if range checking is on
198 and we used a larger request, a whole extra 4096 bytes would be
199 allocated.
201 These number are irrelevant to the new GNU malloc. I suspect it is
202 less sensitive to the size of the request. */
203 int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1))
204 + 4 + DEFAULT_ROUNDING - 1)
205 & ~(DEFAULT_ROUNDING - 1));
206 size = 4096 - extra;
209 h->chunkfun = (struct _obstack_chunk * (*)(void *,long)) chunkfun;
210 h->freefun = (void (*) (void *, struct _obstack_chunk *)) freefun;
211 h->chunk_size = size;
212 h->alignment_mask = alignment - 1;
213 h->extra_arg = arg;
214 h->use_extra_arg = 1;
216 chunk = h->chunk = CALL_CHUNKFUN (h, h -> chunk_size);
217 if (!chunk)
218 (*obstack_alloc_failed_handler) ();
219 h->next_free = h->object_base = __PTR_ALIGN ((char *) chunk, chunk->contents,
220 alignment - 1);
221 h->chunk_limit = chunk->limit
222 = (char *) chunk + h->chunk_size;
223 chunk->prev = NULL;
224 /* The initial chunk now contains no empty object. */
225 h->maybe_empty_object = 0;
226 h->alloc_failed = 0;
227 return 1;
230 /* Allocate a new current chunk for the obstack *H
231 on the assumption that LENGTH bytes need to be added
232 to the current object, or a new object of length LENGTH allocated.
233 Copies any partial object from the end of the old chunk
234 to the beginning of the new one. */
236 void
237 _obstack_newchunk (struct obstack *h, int length)
239 register struct _obstack_chunk *old_chunk = h->chunk;
240 register struct _obstack_chunk *new_chunk;
241 register long new_size;
242 register long obj_size = h->next_free - h->object_base;
243 register long i;
244 long already;
245 char *object_base;
247 /* Compute size for new chunk. */
248 new_size = (obj_size + length) + (obj_size >> 3) + h->alignment_mask + 100;
249 if (new_size < h->chunk_size)
250 new_size = h->chunk_size;
252 /* Allocate and initialize the new chunk. */
253 new_chunk = CALL_CHUNKFUN (h, new_size);
254 if (!new_chunk)
255 (*obstack_alloc_failed_handler) ();
256 h->chunk = new_chunk;
257 new_chunk->prev = old_chunk;
258 new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size;
260 /* Compute an aligned object_base in the new chunk */
261 object_base =
262 __PTR_ALIGN ((char *) new_chunk, new_chunk->contents, h->alignment_mask);
264 /* Move the existing object to the new chunk.
265 Word at a time is fast and is safe if the object
266 is sufficiently aligned. */
267 if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT)
269 for (i = obj_size / sizeof (COPYING_UNIT) - 1;
270 i >= 0; i--)
271 ((COPYING_UNIT *)object_base)[i]
272 = ((COPYING_UNIT *)h->object_base)[i];
273 /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT,
274 but that can cross a page boundary on a machine
275 which does not do strict alignment for COPYING_UNITS. */
276 already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT);
278 else
279 already = 0;
280 /* Copy remaining bytes one by one. */
281 for (i = already; i < obj_size; i++)
282 object_base[i] = h->object_base[i];
284 /* If the object just copied was the only data in OLD_CHUNK,
285 free that chunk and remove it from the chain.
286 But not if that chunk might contain an empty object. */
287 if (! h->maybe_empty_object
288 && (h->object_base
289 == __PTR_ALIGN ((char *) old_chunk, old_chunk->contents,
290 h->alignment_mask)))
292 new_chunk->prev = old_chunk->prev;
293 CALL_FREEFUN (h, old_chunk);
296 h->object_base = object_base;
297 h->next_free = h->object_base + obj_size;
298 /* The new chunk certainly contains no empty object yet. */
299 h->maybe_empty_object = 0;
301 # ifdef _LIBC
302 libc_hidden_def (_obstack_newchunk)
303 # endif
305 /* Return nonzero if object OBJ has been allocated from obstack H.
306 This is here for debugging.
307 If you use it in a program, you are probably losing. */
309 /* Suppress -Wmissing-prototypes warning. We don't want to declare this in
310 obstack.h because it is just for debugging. */
311 int _obstack_allocated_p (struct obstack *h, void *obj);
314 _obstack_allocated_p (struct obstack *h, void *obj)
316 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */
317 register struct _obstack_chunk *plp; /* point to previous chunk if any */
319 lp = (h)->chunk;
320 /* We use >= rather than > since the object cannot be exactly at
321 the beginning of the chunk but might be an empty object exactly
322 at the end of an adjacent chunk. */
323 while (lp != NULL && ((void *) lp >= obj || (void *) (lp)->limit < obj))
325 plp = lp->prev;
326 lp = plp;
328 return lp != NULL;
331 /* Free objects in obstack H, including OBJ and everything allocate
332 more recently than OBJ. If OBJ is zero, free everything in H. */
334 # undef obstack_free
336 void
337 obstack_free (struct obstack *h, void *obj)
339 register struct _obstack_chunk *lp; /* below addr of any objects in this chunk */
340 register struct _obstack_chunk *plp; /* point to previous chunk if any */
342 lp = h->chunk;
343 /* We use >= because there cannot be an object at the beginning of a chunk.
344 But there can be an empty object at that address
345 at the end of another chunk. */
346 while (lp != NULL && ((void *) lp >= obj || (void *) (lp)->limit < obj))
348 plp = lp->prev;
349 CALL_FREEFUN (h, lp);
350 lp = plp;
351 /* If we switch chunks, we can't tell whether the new current
352 chunk contains an empty object, so assume that it may. */
353 h->maybe_empty_object = 1;
355 if (lp)
357 h->object_base = h->next_free = (char *) (obj);
358 h->chunk_limit = lp->limit;
359 h->chunk = lp;
361 else if (obj != NULL)
362 /* obj is not in any of the chunks! */
363 abort ();
366 # ifdef _LIBC
367 /* Older versions of libc used a function _obstack_free intended to be
368 called by non-GCC compilers. */
369 strong_alias (obstack_free, _obstack_free)
370 # endif
373 _obstack_memory_used (struct obstack *h)
375 register struct _obstack_chunk* lp;
376 register int nbytes = 0;
378 for (lp = h->chunk; lp != NULL; lp = lp->prev)
380 nbytes += lp->limit - (char *) lp;
382 return nbytes;
385 # ifdef _LIBC
386 # include <libio/iolibio.h>
387 # endif
389 # ifndef __attribute__
390 /* This feature is available in gcc versions 2.5 and later. */
391 # if __GNUC__ < 2 || (__GNUC__ == 2 && __GNUC_MINOR__ < 5)
392 # define __attribute__(Spec) /* empty */
393 # endif
394 # endif
396 static void
397 print_and_abort (void)
399 /* Don't change any of these strings. Yes, it would be possible to add
400 the newline to the string and use fputs or so. But this must not
401 happen because the "memory exhausted" message appears in other places
402 like this and the translation should be reused instead of creating
403 a very similar string which requires a separate translation. */
404 # ifdef _LIBC
405 (void) __fxprintf (NULL, "%s\n", _("memory exhausted"));
406 # else
407 fprintf (stderr, "%s\n", _("memory exhausted"));
408 # endif
409 exit (1);
412 #endif /* !ELIDE_CODE */