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542e1629 RP |
1 | /* obstack.c - subroutines used implicitly by object stack macros |
2 | Copyright (C) 1988 Free Software Foundation, Inc. | |
3 | ||
4 | This program is free software; you can redistribute it and/or modify it | |
5 | under the terms of the GNU General Public License as published by the | |
6 | Free Software Foundation; either version 2, or (at your option) any | |
7 | later version. | |
8 | ||
9 | This program is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | GNU General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU General Public License | |
15 | along with this program; if not, write to the Free Software | |
16 | Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
17 | ||
18 | #include "obstack.h" | |
19 | ||
20 | #ifdef __STDC__ | |
21 | #define POINTER void * | |
22 | #else | |
23 | #define POINTER char * | |
24 | #endif | |
25 | ||
26 | /* Determine default alignment. */ | |
27 | struct fooalign {char x; double d;}; | |
28 | #define DEFAULT_ALIGNMENT ((char *)&((struct fooalign *) 0)->d - (char *)0) | |
29 | /* If malloc were really smart, it would round addresses to DEFAULT_ALIGNMENT. | |
30 | But in fact it might be less smart and round addresses to as much as | |
31 | DEFAULT_ROUNDING. So we prepare for it to do that. */ | |
32 | union fooround {long x; double d;}; | |
33 | #define DEFAULT_ROUNDING (sizeof (union fooround)) | |
34 | ||
35 | /* When we copy a long block of data, this is the unit to do it with. | |
36 | On some machines, copying successive ints does not work; | |
37 | in such a case, redefine COPYING_UNIT to `long' (if that works) | |
38 | or `char' as a last resort. */ | |
39 | #ifndef COPYING_UNIT | |
40 | #define COPYING_UNIT int | |
41 | #endif | |
42 | ||
43 | /* The non-GNU-C macros copy the obstack into this global variable | |
44 | to avoid multiple evaluation. */ | |
45 | ||
46 | struct obstack *_obstack; | |
47 | \f | |
48 | /* Initialize an obstack H for use. Specify chunk size SIZE (0 means default). | |
49 | Objects start on multiples of ALIGNMENT (0 means use default). | |
50 | CHUNKFUN is the function to use to allocate chunks, | |
51 | and FREEFUN the function to free them. */ | |
52 | ||
53 | void | |
54 | _obstack_begin (h, size, alignment, chunkfun, freefun) | |
55 | struct obstack *h; | |
56 | int size; | |
57 | int alignment; | |
58 | POINTER (*chunkfun) (); | |
59 | void (*freefun) (); | |
60 | { | |
61 | register struct _obstack_chunk* chunk; /* points to new chunk */ | |
62 | ||
63 | if (alignment == 0) | |
64 | alignment = DEFAULT_ALIGNMENT; | |
65 | if (size == 0) | |
66 | /* Default size is what GNU malloc can fit in a 4096-byte block. */ | |
67 | { | |
68 | /* 12 is sizeof (mhead) and 4 is EXTRA from GNU malloc. | |
69 | Use the values for range checking, because if range checking is off, | |
70 | the extra bytes won't be missed terribly, but if range checking is on | |
71 | and we used a larger request, a whole extra 4096 bytes would be | |
72 | allocated. | |
73 | ||
74 | These number are irrelevant to the new GNU malloc. I suspect it is | |
75 | less sensitive to the size of the request. */ | |
76 | int extra = ((((12 + DEFAULT_ROUNDING - 1) & ~(DEFAULT_ROUNDING - 1)) | |
77 | + 4 + DEFAULT_ROUNDING - 1) | |
78 | & ~(DEFAULT_ROUNDING - 1)); | |
79 | size = 4096 - extra; | |
80 | } | |
81 | ||
82 | h->chunkfun = (struct _obstack_chunk * (*)()) chunkfun; | |
83 | h->freefun = freefun; | |
84 | h->chunk_size = size; | |
85 | h->alignment_mask = alignment - 1; | |
86 | ||
87 | chunk = h->chunk = (*h->chunkfun) (h->chunk_size); | |
88 | h->next_free = h->object_base = chunk->contents; | |
89 | h->chunk_limit = chunk->limit | |
90 | = (char *) chunk + h->chunk_size; | |
91 | chunk->prev = 0; | |
92 | /* The initial chunk now contains no empty object. */ | |
93 | h->maybe_empty_object = 0; | |
94 | } | |
95 | ||
96 | /* Allocate a new current chunk for the obstack *H | |
97 | on the assumption that LENGTH bytes need to be added | |
98 | to the current object, or a new object of length LENGTH allocated. | |
99 | Copies any partial object from the end of the old chunk | |
100 | to the beginning of the new one. */ | |
101 | ||
102 | void | |
103 | _obstack_newchunk (h, length) | |
104 | struct obstack *h; | |
105 | int length; | |
106 | { | |
107 | register struct _obstack_chunk* old_chunk = h->chunk; | |
108 | register struct _obstack_chunk* new_chunk; | |
109 | register long new_size; | |
110 | register int obj_size = h->next_free - h->object_base; | |
111 | register int i; | |
112 | int already; | |
113 | ||
114 | /* Compute size for new chunk. */ | |
115 | new_size = (obj_size + length) + (obj_size >> 3) + 100; | |
116 | if (new_size < h->chunk_size) | |
117 | new_size = h->chunk_size; | |
118 | ||
119 | /* Allocate and initialize the new chunk. */ | |
120 | new_chunk = h->chunk = (*h->chunkfun) (new_size); | |
121 | new_chunk->prev = old_chunk; | |
122 | new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size; | |
123 | ||
124 | /* Move the existing object to the new chunk. | |
125 | Word at a time is fast and is safe if the object | |
126 | is sufficiently aligned. */ | |
127 | if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT) | |
128 | { | |
129 | for (i = obj_size / sizeof (COPYING_UNIT) - 1; | |
130 | i >= 0; i--) | |
131 | ((COPYING_UNIT *)new_chunk->contents)[i] | |
132 | = ((COPYING_UNIT *)h->object_base)[i]; | |
133 | /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT, | |
134 | but that can cross a page boundary on a machine | |
135 | which does not do strict alignment for COPYING_UNITS. */ | |
136 | already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT); | |
137 | } | |
138 | else | |
139 | already = 0; | |
140 | /* Copy remaining bytes one by one. */ | |
141 | for (i = already; i < obj_size; i++) | |
142 | new_chunk->contents[i] = h->object_base[i]; | |
143 | ||
144 | /* If the object just copied was the only data in OLD_CHUNK, | |
145 | free that chunk and remove it from the chain. | |
146 | But not if that chunk might contain an empty object. */ | |
147 | if (h->object_base == old_chunk->contents && ! h->maybe_empty_object) | |
148 | { | |
149 | new_chunk->prev = old_chunk->prev; | |
150 | (*h->freefun) (old_chunk); | |
151 | } | |
152 | ||
153 | h->object_base = new_chunk->contents; | |
154 | h->next_free = h->object_base + obj_size; | |
155 | /* The new chunk certainly contains no empty object yet. */ | |
156 | h->maybe_empty_object = 0; | |
157 | } | |
158 | ||
159 | /* Return nonzero if object OBJ has been allocated from obstack H. | |
160 | This is here for debugging. | |
161 | If you use it in a program, you are probably losing. */ | |
162 | ||
163 | int | |
164 | _obstack_allocated_p (h, obj) | |
165 | struct obstack *h; | |
166 | POINTER obj; | |
167 | { | |
168 | register struct _obstack_chunk* lp; /* below addr of any objects in this chunk */ | |
169 | register struct _obstack_chunk* plp; /* point to previous chunk if any */ | |
170 | ||
171 | lp = (h)->chunk; | |
172 | /* We use >= rather than > since the object cannot be exactly at | |
173 | the beginning of the chunk but might be an empty object exactly | |
174 | at the end of an adjacent chunk. */ | |
175 | while (lp != 0 && ((POINTER)lp >= obj || (POINTER)(lp)->limit < obj)) | |
176 | { | |
177 | plp = lp->prev; | |
178 | lp = plp; | |
179 | } | |
180 | return lp != 0; | |
181 | } | |
182 | \f | |
183 | /* Free objects in obstack H, including OBJ and everything allocate | |
184 | more recently than OBJ. If OBJ is zero, free everything in H. */ | |
185 | ||
186 | #undef obstack_free | |
187 | ||
188 | /* This function has two names with identical definitions. | |
189 | This is the first one, called from non-ANSI code. */ | |
190 | ||
191 | void | |
192 | _obstack_free (h, obj) | |
193 | struct obstack *h; | |
194 | POINTER obj; | |
195 | { | |
196 | register struct _obstack_chunk* lp; /* below addr of any objects in this chunk */ | |
197 | register struct _obstack_chunk* plp; /* point to previous chunk if any */ | |
198 | ||
199 | lp = h->chunk; | |
200 | /* We use >= because there cannot be an object at the beginning of a chunk. | |
201 | But there can be an empty object at that address | |
202 | at the end of another chunk. */ | |
203 | while (lp != 0 && ((POINTER)lp >= obj || (POINTER)(lp)->limit < obj)) | |
204 | { | |
205 | plp = lp->prev; | |
206 | (*h->freefun) (lp); | |
207 | lp = plp; | |
208 | /* If we switch chunks, we can't tell whether the new current | |
209 | chunk contains an empty object, so assume that it may. */ | |
210 | h->maybe_empty_object = 1; | |
211 | } | |
212 | if (lp) | |
213 | { | |
214 | h->object_base = h->next_free = (char *)(obj); | |
215 | h->chunk_limit = lp->limit; | |
216 | h->chunk = lp; | |
217 | } | |
218 | else if (obj != 0) | |
219 | /* obj is not in any of the chunks! */ | |
220 | abort (); | |
221 | } | |
222 | ||
223 | /* This function is used from ANSI code. */ | |
224 | ||
225 | void | |
226 | obstack_free (h, obj) | |
227 | struct obstack *h; | |
228 | POINTER obj; | |
229 | { | |
230 | register struct _obstack_chunk* lp; /* below addr of any objects in this chunk */ | |
231 | register struct _obstack_chunk* plp; /* point to previous chunk if any */ | |
232 | ||
233 | lp = h->chunk; | |
234 | /* We use >= because there cannot be an object at the beginning of a chunk. | |
235 | But there can be an empty object at that address | |
236 | at the end of another chunk. */ | |
237 | while (lp != 0 && ((POINTER)lp >= obj || (POINTER)(lp)->limit < obj)) | |
238 | { | |
239 | plp = lp->prev; | |
240 | (*h->freefun) (lp); | |
241 | lp = plp; | |
242 | /* If we switch chunks, we can't tell whether the new current | |
243 | chunk contains an empty object, so assume that it may. */ | |
244 | h->maybe_empty_object = 1; | |
245 | } | |
246 | if (lp) | |
247 | { | |
248 | h->object_base = h->next_free = (char *)(obj); | |
249 | h->chunk_limit = lp->limit; | |
250 | h->chunk = lp; | |
251 | } | |
252 | else if (obj != 0) | |
253 | /* obj is not in any of the chunks! */ | |
254 | abort (); | |
255 | } | |
256 | \f | |
257 | #if 0 | |
258 | /* These are now turned off because the applications do not use it | |
259 | and it uses bcopy via obstack_grow, which causes trouble on sysV. */ | |
260 | ||
261 | /* Now define the functional versions of the obstack macros. | |
262 | Define them to simply use the corresponding macros to do the job. */ | |
263 | ||
264 | #ifdef __STDC__ | |
265 | /* These function definitions do not work with non-ANSI preprocessors; | |
266 | they won't pass through the macro names in parentheses. */ | |
267 | ||
268 | /* The function names appear in parentheses in order to prevent | |
269 | the macro-definitions of the names from being expanded there. */ | |
270 | ||
271 | POINTER (obstack_base) (obstack) | |
272 | struct obstack *obstack; | |
273 | { | |
274 | return obstack_base (obstack); | |
275 | } | |
276 | ||
277 | POINTER (obstack_next_free) (obstack) | |
278 | struct obstack *obstack; | |
279 | { | |
280 | return obstack_next_free (obstack); | |
281 | } | |
282 | ||
283 | int (obstack_object_size) (obstack) | |
284 | struct obstack *obstack; | |
285 | { | |
286 | return obstack_object_size (obstack); | |
287 | } | |
288 | ||
289 | int (obstack_room) (obstack) | |
290 | struct obstack *obstack; | |
291 | { | |
292 | return obstack_room (obstack); | |
293 | } | |
294 | ||
295 | void (obstack_grow) (obstack, pointer, length) | |
296 | struct obstack *obstack; | |
297 | POINTER pointer; | |
298 | int length; | |
299 | { | |
300 | obstack_grow (obstack, pointer, length); | |
301 | } | |
302 | ||
303 | void (obstack_grow0) (obstack, pointer, length) | |
304 | struct obstack *obstack; | |
305 | POINTER pointer; | |
306 | int length; | |
307 | { | |
308 | obstack_grow0 (obstack, pointer, length); | |
309 | } | |
310 | ||
311 | void (obstack_1grow) (obstack, character) | |
312 | struct obstack *obstack; | |
313 | int character; | |
314 | { | |
315 | obstack_1grow (obstack, character); | |
316 | } | |
317 | ||
318 | void (obstack_blank) (obstack, length) | |
319 | struct obstack *obstack; | |
320 | int length; | |
321 | { | |
322 | obstack_blank (obstack, length); | |
323 | } | |
324 | ||
325 | void (obstack_1grow_fast) (obstack, character) | |
326 | struct obstack *obstack; | |
327 | int character; | |
328 | { | |
329 | obstack_1grow_fast (obstack, character); | |
330 | } | |
331 | ||
332 | void (obstack_blank_fast) (obstack, length) | |
333 | struct obstack *obstack; | |
334 | int length; | |
335 | { | |
336 | obstack_blank_fast (obstack, length); | |
337 | } | |
338 | ||
339 | POINTER (obstack_finish) (obstack) | |
340 | struct obstack *obstack; | |
341 | { | |
342 | return obstack_finish (obstack); | |
343 | } | |
344 | ||
345 | POINTER (obstack_alloc) (obstack, length) | |
346 | struct obstack *obstack; | |
347 | int length; | |
348 | { | |
349 | return obstack_alloc (obstack, length); | |
350 | } | |
351 | ||
352 | POINTER (obstack_copy) (obstack, pointer, length) | |
353 | struct obstack *obstack; | |
354 | POINTER pointer; | |
355 | int length; | |
356 | { | |
357 | return obstack_copy (obstack, pointer, length); | |
358 | } | |
359 | ||
360 | POINTER (obstack_copy0) (obstack, pointer, length) | |
361 | struct obstack *obstack; | |
362 | POINTER pointer; | |
363 | int length; | |
364 | { | |
365 | return obstack_copy0 (obstack, pointer, length); | |
366 | } | |
367 | ||
368 | #endif /* __STDC__ */ | |
369 | ||
370 | #endif /* 0 */ |