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6df334d6 C |
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 1, 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 | } | |
93 | ||
94 | /* Allocate a new current chunk for the obstack *H | |
95 | on the assumption that LENGTH bytes need to be added | |
96 | to the current object, or a new object of length LENGTH allocated. | |
97 | Copies any partial object from the end of the old chunk | |
98 | to the beginning of the new one. */ | |
99 | ||
100 | void | |
101 | _obstack_newchunk (h, length) | |
102 | struct obstack *h; | |
103 | int length; | |
104 | { | |
105 | register struct _obstack_chunk* old_chunk = h->chunk; | |
106 | register struct _obstack_chunk* new_chunk; | |
107 | register long new_size; | |
108 | register int obj_size = h->next_free - h->object_base; | |
109 | register int i; | |
110 | int already; | |
111 | ||
112 | /* Compute size for new chunk. */ | |
113 | new_size = (obj_size + length) + (obj_size >> 3) + 100; | |
114 | if (new_size < h->chunk_size) | |
115 | new_size = h->chunk_size; | |
116 | ||
117 | /* Allocate and initialize the new chunk. */ | |
118 | new_chunk = h->chunk = (*h->chunkfun) (new_size); | |
119 | new_chunk->prev = old_chunk; | |
120 | new_chunk->limit = h->chunk_limit = (char *) new_chunk + new_size; | |
121 | ||
122 | /* Move the existing object to the new chunk. | |
123 | Word at a time is fast and is safe if the object | |
124 | is sufficiently aligned. */ | |
125 | if (h->alignment_mask + 1 >= DEFAULT_ALIGNMENT) | |
126 | { | |
127 | for (i = obj_size / sizeof (COPYING_UNIT) - 1; | |
128 | i >= 0; i--) | |
129 | ((COPYING_UNIT *)new_chunk->contents)[i] | |
130 | = ((COPYING_UNIT *)h->object_base)[i]; | |
131 | /* We used to copy the odd few remaining bytes as one extra COPYING_UNIT, | |
132 | but that can cross a page boundary on a machine | |
133 | which does not do strict alignment for COPYING_UNITS. */ | |
134 | already = obj_size / sizeof (COPYING_UNIT) * sizeof (COPYING_UNIT); | |
135 | } | |
136 | else | |
137 | already = 0; | |
138 | /* Copy remaining bytes one by one. */ | |
139 | for (i = already; i < obj_size; i++) | |
140 | new_chunk->contents[i] = h->object_base[i]; | |
141 | ||
142 | /* If the object just copied was the only data in OLD_CHUNK, | |
143 | free that chunk and remove it from the chain. */ | |
144 | if (h->object_base == old_chunk->contents) | |
145 | { | |
146 | new_chunk->prev = old_chunk->prev; | |
147 | (*h->freefun) (old_chunk); | |
148 | } | |
149 | ||
150 | h->object_base = new_chunk->contents; | |
151 | h->next_free = h->object_base + obj_size; | |
152 | } | |
153 | ||
154 | /* Return nonzero if object OBJ has been allocated from obstack H. | |
155 | This is here for debugging. | |
156 | If you use it in a program, you are probably losing. */ | |
157 | ||
158 | int | |
159 | _obstack_allocated_p (h, obj) | |
160 | struct obstack *h; | |
161 | POINTER obj; | |
162 | { | |
163 | register struct _obstack_chunk* lp; /* below addr of any objects in this chunk */ | |
164 | register struct _obstack_chunk* plp; /* point to previous chunk if any */ | |
165 | ||
166 | lp = (h)->chunk; | |
167 | while (lp != 0 && ((POINTER)lp > obj || (POINTER)(lp)->limit < obj)) | |
168 | { | |
169 | plp = lp -> prev; | |
170 | lp = plp; | |
171 | } | |
172 | return lp != 0; | |
173 | } | |
174 | ||
175 | /* Free objects in obstack H, including OBJ and everything allocate | |
176 | more recently than OBJ. If OBJ is zero, free everything in H. */ | |
177 | ||
178 | void | |
179 | #ifdef __STDC__ | |
180 | #undef obstack_free | |
181 | obstack_free (struct obstack *h, POINTER obj) | |
182 | #else | |
183 | _obstack_free (h, obj) | |
184 | struct obstack *h; | |
185 | POINTER obj; | |
186 | #endif | |
187 | { | |
188 | register struct _obstack_chunk* lp; /* below addr of any objects in this chunk */ | |
189 | register struct _obstack_chunk* plp; /* point to previous chunk if any */ | |
190 | ||
191 | lp = (h)->chunk; | |
192 | /* We use >= because there cannot be an object at the beginning of a chunk. | |
193 | But there can be an empty object at that address | |
194 | at the end of another chunk. */ | |
195 | while (lp != 0 && ((POINTER)lp >= obj || (POINTER)(lp)->limit < obj)) | |
196 | { | |
197 | plp = lp -> prev; | |
198 | (*h->freefun) (lp); | |
199 | lp = plp; | |
200 | } | |
201 | if (lp) | |
202 | { | |
203 | (h)->object_base = (h)->next_free = (char *)(obj); | |
204 | (h)->chunk_limit = lp->limit; | |
205 | (h)->chunk = lp; | |
206 | } | |
207 | else if (obj != 0) | |
208 | /* obj is not in any of the chunks! */ | |
209 | abort (); | |
210 | } | |
211 | ||
212 | /* Let same .o link with output of gcc and other compilers. */ | |
213 | ||
214 | #ifdef __STDC__ | |
215 | void | |
216 | _obstack_free (h, obj) | |
217 | struct obstack *h; | |
218 | POINTER obj; | |
219 | { | |
220 | obstack_free (h, obj); | |
221 | } | |
222 | #endif | |
223 | \f | |
224 | #if 0 | |
225 | /* These are now turned off because the applications do not use it | |
226 | and it uses bcopy via obstack_grow, which causes trouble on sysV. */ | |
227 | ||
228 | /* Now define the functional versions of the obstack macros. | |
229 | Define them to simply use the corresponding macros to do the job. */ | |
230 | ||
231 | #ifdef __STDC__ | |
232 | /* These function definitions do not work with non-ANSI preprocessors; | |
233 | they won't pass through the macro names in parentheses. */ | |
234 | ||
235 | /* The function names appear in parentheses in order to prevent | |
236 | the macro-definitions of the names from being expanded there. */ | |
237 | ||
238 | POINTER (obstack_base) (obstack) | |
239 | struct obstack *obstack; | |
240 | { | |
241 | return obstack_base (obstack); | |
242 | } | |
243 | ||
244 | POINTER (obstack_next_free) (obstack) | |
245 | struct obstack *obstack; | |
246 | { | |
247 | return obstack_next_free (obstack); | |
248 | } | |
249 | ||
250 | int (obstack_object_size) (obstack) | |
251 | struct obstack *obstack; | |
252 | { | |
253 | return obstack_object_size (obstack); | |
254 | } | |
255 | ||
256 | int (obstack_room) (obstack) | |
257 | struct obstack *obstack; | |
258 | { | |
259 | return obstack_room (obstack); | |
260 | } | |
261 | ||
262 | void (obstack_grow) (obstack, pointer, length) | |
263 | struct obstack *obstack; | |
264 | POINTER pointer; | |
265 | int length; | |
266 | { | |
267 | obstack_grow (obstack, pointer, length); | |
268 | } | |
269 | ||
270 | void (obstack_grow0) (obstack, pointer, length) | |
271 | struct obstack *obstack; | |
272 | POINTER pointer; | |
273 | int length; | |
274 | { | |
275 | obstack_grow0 (obstack, pointer, length); | |
276 | } | |
277 | ||
278 | void (obstack_1grow) (obstack, character) | |
279 | struct obstack *obstack; | |
280 | int character; | |
281 | { | |
282 | obstack_1grow (obstack, character); | |
283 | } | |
284 | ||
285 | void (obstack_blank) (obstack, length) | |
286 | struct obstack *obstack; | |
287 | int length; | |
288 | { | |
289 | obstack_blank (obstack, length); | |
290 | } | |
291 | ||
292 | void (obstack_1grow_fast) (obstack, character) | |
293 | struct obstack *obstack; | |
294 | int character; | |
295 | { | |
296 | obstack_1grow_fast (obstack, character); | |
297 | } | |
298 | ||
299 | void (obstack_blank_fast) (obstack, length) | |
300 | struct obstack *obstack; | |
301 | int length; | |
302 | { | |
303 | obstack_blank_fast (obstack, length); | |
304 | } | |
305 | ||
306 | POINTER (obstack_finish) (obstack) | |
307 | struct obstack *obstack; | |
308 | { | |
309 | return obstack_finish (obstack); | |
310 | } | |
311 | ||
312 | POINTER (obstack_alloc) (obstack, length) | |
313 | struct obstack *obstack; | |
314 | int length; | |
315 | { | |
316 | return obstack_alloc (obstack, length); | |
317 | } | |
318 | ||
319 | POINTER (obstack_copy) (obstack, pointer, length) | |
320 | struct obstack *obstack; | |
321 | POINTER pointer; | |
322 | int length; | |
323 | { | |
324 | return obstack_copy (obstack, pointer, length); | |
325 | } | |
326 | ||
327 | POINTER (obstack_copy0) (obstack, pointer, length) | |
328 | struct obstack *obstack; | |
329 | POINTER pointer; | |
330 | int length; | |
331 | { | |
332 | return obstack_copy0 (obstack, pointer, length); | |
333 | } | |
334 | ||
335 | #endif /* __STDC__ */ | |
336 | ||
337 | #endif /* 0 */ |