source: cpio/vendor/current/gnu/obstack.h@ 1964

Last change on this file since 1964 was 1964, checked in by Silvan Scherrer, 8 years ago

cpio: update vendor to version 2.12
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1/* obstack.h - object stack macros
2 Copyright (C) 1988-2015 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU General Public
7 License as published by the Free Software Foundation; either
8 version 3 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 General Public License for more details.
14
15 You should have received a copy of the GNU General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19/* Summary:
20
21 All the apparent functions defined here are macros. The idea
22 is that you would use these pre-tested macros to solve a
23 very specific set of problems, and they would run fast.
24 Caution: no side-effects in arguments please!! They may be
25 evaluated MANY times!!
26
27 These macros operate a stack of objects. Each object starts life
28 small, and may grow to maturity. (Consider building a word syllable
29 by syllable.) An object can move while it is growing. Once it has
30 been "finished" it never changes address again. So the "top of the
31 stack" is typically an immature growing object, while the rest of the
32 stack is of mature, fixed size and fixed address objects.
33
34 These routines grab large chunks of memory, using a function you
35 supply, called 'obstack_chunk_alloc'. On occasion, they free chunks,
36 by calling 'obstack_chunk_free'. You must define them and declare
37 them before using any obstack macros.
38
39 Each independent stack is represented by a 'struct obstack'.
40 Each of the obstack macros expects a pointer to such a structure
41 as the first argument.
42
43 One motivation for this package is the problem of growing char strings
44 in symbol tables. Unless you are "fascist pig with a read-only mind"
45 --Gosper's immortal quote from HAKMEM item 154, out of context--you
46 would not like to put any arbitrary upper limit on the length of your
47 symbols.
48
49 In practice this often means you will build many short symbols and a
50 few long symbols. At the time you are reading a symbol you don't know
51 how long it is. One traditional method is to read a symbol into a
52 buffer, realloc()ating the buffer every time you try to read a symbol
53 that is longer than the buffer. This is beaut, but you still will
54 want to copy the symbol from the buffer to a more permanent
55 symbol-table entry say about half the time.
56
57 With obstacks, you can work differently. Use one obstack for all symbol
58 names. As you read a symbol, grow the name in the obstack gradually.
59 When the name is complete, finalize it. Then, if the symbol exists already,
60 free the newly read name.
61
62 The way we do this is to take a large chunk, allocating memory from
63 low addresses. When you want to build a symbol in the chunk you just
64 add chars above the current "high water mark" in the chunk. When you
65 have finished adding chars, because you got to the end of the symbol,
66 you know how long the chars are, and you can create a new object.
67 Mostly the chars will not burst over the highest address of the chunk,
68 because you would typically expect a chunk to be (say) 100 times as
69 long as an average object.
70
71 In case that isn't clear, when we have enough chars to make up
72 the object, THEY ARE ALREADY CONTIGUOUS IN THE CHUNK (guaranteed)
73 so we just point to it where it lies. No moving of chars is
74 needed and this is the second win: potentially long strings need
75 never be explicitly shuffled. Once an object is formed, it does not
76 change its address during its lifetime.
77
78 When the chars burst over a chunk boundary, we allocate a larger
79 chunk, and then copy the partly formed object from the end of the old
80 chunk to the beginning of the new larger chunk. We then carry on
81 accreting characters to the end of the object as we normally would.
82
83 A special macro is provided to add a single char at a time to a
84 growing object. This allows the use of register variables, which
85 break the ordinary 'growth' macro.
86
87 Summary:
88 We allocate large chunks.
89 We carve out one object at a time from the current chunk.
90 Once carved, an object never moves.
91 We are free to append data of any size to the currently
92 growing object.
93 Exactly one object is growing in an obstack at any one time.
94 You can run one obstack per control block.
95 You may have as many control blocks as you dare.
96 Because of the way we do it, you can "unwind" an obstack
97 back to a previous state. (You may remove objects much
98 as you would with a stack.)
99 */
100
101
102/* Don't do the contents of this file more than once. */
103
104#ifndef _OBSTACK_H
105#define _OBSTACK_H 1
106
107#ifndef _OBSTACK_INTERFACE_VERSION
108# define _OBSTACK_INTERFACE_VERSION 2
109#endif
110
111#include <stddef.h> /* For size_t and ptrdiff_t. */
112#include <string.h> /* For __GNU_LIBRARY__, and memcpy. */
113
114#if _OBSTACK_INTERFACE_VERSION == 1
115/* For binary compatibility with obstack version 1, which used "int"
116 and "long" for these two types. */
117# define _OBSTACK_SIZE_T unsigned int
118# define _CHUNK_SIZE_T unsigned long
119# define _OBSTACK_CAST(type, expr) ((type) (expr))
120#else
121/* Version 2 with sane types, especially for 64-bit hosts. */
122# define _OBSTACK_SIZE_T size_t
123# define _CHUNK_SIZE_T size_t
124# define _OBSTACK_CAST(type, expr) (expr)
125#endif
126
127/* If B is the base of an object addressed by P, return the result of
128 aligning P to the next multiple of A + 1. B and P must be of type
129 char *. A + 1 must be a power of 2. */
130
131#define __BPTR_ALIGN(B, P, A) ((B) + (((P) - (B) + (A)) & ~(A)))
132
133/* Similar to __BPTR_ALIGN (B, P, A), except optimize the common case
134 where pointers can be converted to integers, aligned as integers,
135 and converted back again. If ptrdiff_t is narrower than a
136 pointer (e.g., the AS/400), play it safe and compute the alignment
137 relative to B. Otherwise, use the faster strategy of computing the
138 alignment relative to 0. */
139
140#define __PTR_ALIGN(B, P, A) \
141 __BPTR_ALIGN (sizeof (ptrdiff_t) < sizeof (void *) ? (B) : (char *) 0, \
142 P, A)
143
144#ifndef __attribute_pure__
145# define __attribute_pure__ _GL_ATTRIBUTE_PURE
146#endif
147
148#ifdef __cplusplus
149extern "C" {
150#endif
151
152struct _obstack_chunk /* Lives at front of each chunk. */
153{
154 char *limit; /* 1 past end of this chunk */
155 struct _obstack_chunk *prev; /* address of prior chunk or NULL */
156 char contents[4]; /* objects begin here */
157};
158
159struct obstack /* control current object in current chunk */
160{
161 _CHUNK_SIZE_T chunk_size; /* preferred size to allocate chunks in */
162 struct _obstack_chunk *chunk; /* address of current struct obstack_chunk */
163 char *object_base; /* address of object we are building */
164 char *next_free; /* where to add next char to current object */
165 char *chunk_limit; /* address of char after current chunk */
166 union
167 {
168 _OBSTACK_SIZE_T i;
169 void *p;
170 } temp; /* Temporary for some macros. */
171 _OBSTACK_SIZE_T alignment_mask; /* Mask of alignment for each object. */
172
173 /* These prototypes vary based on 'use_extra_arg'. */
174 union
175 {
176 void *(*plain) (size_t);
177 void *(*extra) (void *, size_t);
178 } chunkfun;
179 union
180 {
181 void (*plain) (void *);
182 void (*extra) (void *, void *);
183 } freefun;
184
185 void *extra_arg; /* first arg for chunk alloc/dealloc funcs */
186 unsigned use_extra_arg : 1; /* chunk alloc/dealloc funcs take extra arg */
187 unsigned maybe_empty_object : 1; /* There is a possibility that the current
188 chunk contains a zero-length object. This
189 prevents freeing the chunk if we allocate
190 a bigger chunk to replace it. */
191 unsigned alloc_failed : 1; /* No longer used, as we now call the failed
192 handler on error, but retained for binary
193 compatibility. */
194};
195
196/* Declare the external functions we use; they are in obstack.c. */
197
198extern void _obstack_newchunk (struct obstack *, _OBSTACK_SIZE_T);
199extern void _obstack_free (struct obstack *, void *);
200extern int _obstack_begin (struct obstack *,
201 _OBSTACK_SIZE_T, _OBSTACK_SIZE_T,
202 void *(*) (size_t), void (*) (void *));
203extern int _obstack_begin_1 (struct obstack *,
204 _OBSTACK_SIZE_T, _OBSTACK_SIZE_T,
205 void *(*) (void *, size_t),
206 void (*) (void *, void *), void *);
207extern _OBSTACK_SIZE_T _obstack_memory_used (struct obstack *)
208 __attribute_pure__;
209
210
211/* Error handler called when 'obstack_chunk_alloc' failed to allocate
212 more memory. This can be set to a user defined function which
213 should either abort gracefully or use longjump - but shouldn't
214 return. The default action is to print a message and abort. */
215extern void (*obstack_alloc_failed_handler) (void);
216
217/* Exit value used when 'print_and_abort' is used. */
218extern int obstack_exit_failure;
219
220/* Pointer to beginning of object being allocated or to be allocated next.
221 Note that this might not be the final address of the object
222 because a new chunk might be needed to hold the final size. */
223
224#define obstack_base(h) ((void *) (h)->object_base)
225
226/* Size for allocating ordinary chunks. */
227
228#define obstack_chunk_size(h) ((h)->chunk_size)
229
230/* Pointer to next byte not yet allocated in current chunk. */
231
232#define obstack_next_free(h) ((void *) (h)->next_free)
233
234/* Mask specifying low bits that should be clear in address of an object. */
235
236#define obstack_alignment_mask(h) ((h)->alignment_mask)
237
238/* To prevent prototype warnings provide complete argument list. */
239#define obstack_init(h) \
240 _obstack_begin ((h), 0, 0, \
241 _OBSTACK_CAST (void *(*) (size_t), obstack_chunk_alloc), \
242 _OBSTACK_CAST (void (*) (void *), obstack_chunk_free))
243
244#define obstack_begin(h, size) \
245 _obstack_begin ((h), (size), 0, \
246 _OBSTACK_CAST (void *(*) (size_t), obstack_chunk_alloc), \
247 _OBSTACK_CAST (void (*) (void *), obstack_chunk_free))
248
249#define obstack_specify_allocation(h, size, alignment, chunkfun, freefun) \
250 _obstack_begin ((h), (size), (alignment), \
251 _OBSTACK_CAST (void *(*) (size_t), chunkfun), \
252 _OBSTACK_CAST (void (*) (void *), freefun))
253
254#define obstack_specify_allocation_with_arg(h, size, alignment, chunkfun, freefun, arg) \
255 _obstack_begin_1 ((h), (size), (alignment), \
256 _OBSTACK_CAST (void *(*) (void *, size_t), chunkfun), \
257 _OBSTACK_CAST (void (*) (void *, void *), freefun), arg)
258
259#define obstack_chunkfun(h, newchunkfun) \
260 ((void) ((h)->chunkfun.extra = (void *(*) (void *, size_t)) (newchunkfun)))
261
262#define obstack_freefun(h, newfreefun) \
263 ((void) ((h)->freefun.extra = (void *(*) (void *, void *)) (newfreefun)))
264
265#define obstack_1grow_fast(h, achar) ((void) (*((h)->next_free)++ = (achar)))
266
267#define obstack_blank_fast(h, n) ((void) ((h)->next_free += (n)))
268
269#define obstack_memory_used(h) _obstack_memory_used (h)
270
271#if defined __GNUC__
272# if !defined __GNUC_MINOR__ || __GNUC__ * 1000 + __GNUC_MINOR__ < 2008
273# define __extension__
274# endif
275
276/* For GNU C, if not -traditional,
277 we can define these macros to compute all args only once
278 without using a global variable.
279 Also, we can avoid using the 'temp' slot, to make faster code. */
280
281# define obstack_object_size(OBSTACK) \
282 __extension__ \
283 ({ struct obstack const *__o = (OBSTACK); \
284 (_OBSTACK_SIZE_T) (__o->next_free - __o->object_base); })
285
286/* The local variable is named __o1 to avoid a shadowed variable
287 warning when invoked from other obstack macros. */
288# define obstack_room(OBSTACK) \
289 __extension__ \
290 ({ struct obstack const *__o1 = (OBSTACK); \
291 (_OBSTACK_SIZE_T) (__o1->chunk_limit - __o1->next_free); })
292
293# define obstack_make_room(OBSTACK, length) \
294 __extension__ \
295 ({ struct obstack *__o = (OBSTACK); \
296 _OBSTACK_SIZE_T __len = (length); \
297 if (obstack_room (__o) < __len) \
298 _obstack_newchunk (__o, __len); \
299 (void) 0; })
300
301# define obstack_empty_p(OBSTACK) \
302 __extension__ \
303 ({ struct obstack const *__o = (OBSTACK); \
304 (__o->chunk->prev == 0 \
305 && __o->next_free == __PTR_ALIGN ((char *) __o->chunk, \
306 __o->chunk->contents, \
307 __o->alignment_mask)); })
308
309# define obstack_grow(OBSTACK, where, length) \
310 __extension__ \
311 ({ struct obstack *__o = (OBSTACK); \
312 _OBSTACK_SIZE_T __len = (length); \
313 if (obstack_room (__o) < __len) \
314 _obstack_newchunk (__o, __len); \
315 memcpy (__o->next_free, where, __len); \
316 __o->next_free += __len; \
317 (void) 0; })
318
319# define obstack_grow0(OBSTACK, where, length) \
320 __extension__ \
321 ({ struct obstack *__o = (OBSTACK); \
322 _OBSTACK_SIZE_T __len = (length); \
323 if (obstack_room (__o) < __len + 1) \
324 _obstack_newchunk (__o, __len + 1); \
325 memcpy (__o->next_free, where, __len); \
326 __o->next_free += __len; \
327 *(__o->next_free)++ = 0; \
328 (void) 0; })
329
330# define obstack_1grow(OBSTACK, datum) \
331 __extension__ \
332 ({ struct obstack *__o = (OBSTACK); \
333 if (obstack_room (__o) < 1) \
334 _obstack_newchunk (__o, 1); \
335 obstack_1grow_fast (__o, datum); })
336
337/* These assume that the obstack alignment is good enough for pointers
338 or ints, and that the data added so far to the current object
339 shares that much alignment. */
340
341# define obstack_ptr_grow(OBSTACK, datum) \
342 __extension__ \
343 ({ struct obstack *__o = (OBSTACK); \
344 if (obstack_room (__o) < sizeof (void *)) \
345 _obstack_newchunk (__o, sizeof (void *)); \
346 obstack_ptr_grow_fast (__o, datum); })
347
348# define obstack_int_grow(OBSTACK, datum) \
349 __extension__ \
350 ({ struct obstack *__o = (OBSTACK); \
351 if (obstack_room (__o) < sizeof (int)) \
352 _obstack_newchunk (__o, sizeof (int)); \
353 obstack_int_grow_fast (__o, datum); })
354
355# define obstack_ptr_grow_fast(OBSTACK, aptr) \
356 __extension__ \
357 ({ struct obstack *__o1 = (OBSTACK); \
358 void *__p1 = __o1->next_free; \
359 *(const void **) __p1 = (aptr); \
360 __o1->next_free += sizeof (const void *); \
361 (void) 0; })
362
363# define obstack_int_grow_fast(OBSTACK, aint) \
364 __extension__ \
365 ({ struct obstack *__o1 = (OBSTACK); \
366 void *__p1 = __o1->next_free; \
367 *(int *) __p1 = (aint); \
368 __o1->next_free += sizeof (int); \
369 (void) 0; })
370
371# define obstack_blank(OBSTACK, length) \
372 __extension__ \
373 ({ struct obstack *__o = (OBSTACK); \
374 _OBSTACK_SIZE_T __len = (length); \
375 if (obstack_room (__o) < __len) \
376 _obstack_newchunk (__o, __len); \
377 obstack_blank_fast (__o, __len); })
378
379# define obstack_alloc(OBSTACK, length) \
380 __extension__ \
381 ({ struct obstack *__h = (OBSTACK); \
382 obstack_blank (__h, (length)); \
383 obstack_finish (__h); })
384
385# define obstack_copy(OBSTACK, where, length) \
386 __extension__ \
387 ({ struct obstack *__h = (OBSTACK); \
388 obstack_grow (__h, (where), (length)); \
389 obstack_finish (__h); })
390
391# define obstack_copy0(OBSTACK, where, length) \
392 __extension__ \
393 ({ struct obstack *__h = (OBSTACK); \
394 obstack_grow0 (__h, (where), (length)); \
395 obstack_finish (__h); })
396
397/* The local variable is named __o1 to avoid a shadowed variable
398 warning when invoked from other obstack macros, typically obstack_free. */
399# define obstack_finish(OBSTACK) \
400 __extension__ \
401 ({ struct obstack *__o1 = (OBSTACK); \
402 void *__value = (void *) __o1->object_base; \
403 if (__o1->next_free == __value) \
404 __o1->maybe_empty_object = 1; \
405 __o1->next_free \
406 = __PTR_ALIGN (__o1->object_base, __o1->next_free, \
407 __o1->alignment_mask); \
408 if ((size_t) (__o1->next_free - (char *) __o1->chunk) \
409 > (size_t) (__o1->chunk_limit - (char *) __o1->chunk)) \
410 __o1->next_free = __o1->chunk_limit; \
411 __o1->object_base = __o1->next_free; \
412 __value; })
413
414# define obstack_free(OBSTACK, OBJ) \
415 __extension__ \
416 ({ struct obstack *__o = (OBSTACK); \
417 void *__obj = (void *) (OBJ); \
418 if (__obj > (void *) __o->chunk && __obj < (void *) __o->chunk_limit) \
419 __o->next_free = __o->object_base = (char *) __obj; \
420 else \
421 _obstack_free (__o, __obj); })
422
423#else /* not __GNUC__ */
424
425# define obstack_object_size(h) \
426 ((_OBSTACK_SIZE_T) ((h)->next_free - (h)->object_base))
427
428# define obstack_room(h) \
429 ((_OBSTACK_SIZE_T) ((h)->chunk_limit - (h)->next_free))
430
431# define obstack_empty_p(h) \
432 ((h)->chunk->prev == 0 \
433 && (h)->next_free == __PTR_ALIGN ((char *) (h)->chunk, \
434 (h)->chunk->contents, \
435 (h)->alignment_mask))
436
437/* Note that the call to _obstack_newchunk is enclosed in (..., 0)
438 so that we can avoid having void expressions
439 in the arms of the conditional expression.
440 Casting the third operand to void was tried before,
441 but some compilers won't accept it. */
442
443# define obstack_make_room(h, length) \
444 ((h)->temp.i = (length), \
445 ((obstack_room (h) < (h)->temp.i) \
446 ? (_obstack_newchunk (h, (h)->temp.i), 0) : 0), \
447 (void) 0)
448
449# define obstack_grow(h, where, length) \
450 ((h)->temp.i = (length), \
451 ((obstack_room (h) < (h)->temp.i) \
452 ? (_obstack_newchunk ((h), (h)->temp.i), 0) : 0), \
453 memcpy ((h)->next_free, where, (h)->temp.i), \
454 (h)->next_free += (h)->temp.i, \
455 (void) 0)
456
457# define obstack_grow0(h, where, length) \
458 ((h)->temp.i = (length), \
459 ((obstack_room (h) < (h)->temp.i + 1) \
460 ? (_obstack_newchunk ((h), (h)->temp.i + 1), 0) : 0), \
461 memcpy ((h)->next_free, where, (h)->temp.i), \
462 (h)->next_free += (h)->temp.i, \
463 *((h)->next_free)++ = 0, \
464 (void) 0)
465
466# define obstack_1grow(h, datum) \
467 (((obstack_room (h) < 1) \
468 ? (_obstack_newchunk ((h), 1), 0) : 0), \
469 obstack_1grow_fast (h, datum))
470
471# define obstack_ptr_grow(h, datum) \
472 (((obstack_room (h) < sizeof (char *)) \
473 ? (_obstack_newchunk ((h), sizeof (char *)), 0) : 0), \
474 obstack_ptr_grow_fast (h, datum))
475
476# define obstack_int_grow(h, datum) \
477 (((obstack_room (h) < sizeof (int)) \
478 ? (_obstack_newchunk ((h), sizeof (int)), 0) : 0), \
479 obstack_int_grow_fast (h, datum))
480
481# define obstack_ptr_grow_fast(h, aptr) \
482 (((const void **) ((h)->next_free += sizeof (void *)))[-1] = (aptr), \
483 (void) 0)
484
485# define obstack_int_grow_fast(h, aint) \
486 (((int *) ((h)->next_free += sizeof (int)))[-1] = (aint), \
487 (void) 0)
488
489# define obstack_blank(h, length) \
490 ((h)->temp.i = (length), \
491 ((obstack_room (h) < (h)->temp.i) \
492 ? (_obstack_newchunk ((h), (h)->temp.i), 0) : 0), \
493 obstack_blank_fast (h, (h)->temp.i))
494
495# define obstack_alloc(h, length) \
496 (obstack_blank ((h), (length)), obstack_finish ((h)))
497
498# define obstack_copy(h, where, length) \
499 (obstack_grow ((h), (where), (length)), obstack_finish ((h)))
500
501# define obstack_copy0(h, where, length) \
502 (obstack_grow0 ((h), (where), (length)), obstack_finish ((h)))
503
504# define obstack_finish(h) \
505 (((h)->next_free == (h)->object_base \
506 ? (((h)->maybe_empty_object = 1), 0) \
507 : 0), \
508 (h)->temp.p = (h)->object_base, \
509 (h)->next_free \
510 = __PTR_ALIGN ((h)->object_base, (h)->next_free, \
511 (h)->alignment_mask), \
512 (((size_t) ((h)->next_free - (char *) (h)->chunk) \
513 > (size_t) ((h)->chunk_limit - (char *) (h)->chunk)) \
514 ? ((h)->next_free = (h)->chunk_limit) : 0), \
515 (h)->object_base = (h)->next_free, \
516 (h)->temp.p)
517
518# define obstack_free(h, obj) \
519 ((h)->temp.p = (void *) (obj), \
520 (((h)->temp.p > (void *) (h)->chunk \
521 && (h)->temp.p < (void *) (h)->chunk_limit) \
522 ? (void) ((h)->next_free = (h)->object_base = (char *) (h)->temp.p) \
523 : _obstack_free ((h), (h)->temp.p)))
524
525#endif /* not __GNUC__ */
526
527#ifdef __cplusplus
528} /* C++ */
529#endif
530
531#endif /* _OBSTACK_H */
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