aboutsummaryrefslogtreecommitdiff
path: root/gdb/obstack.h
blob: 069afc6a1e95d708772740e9c1d66e9a140a0136 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
/* obstack.h - object stack macros
   Copyright (C) 1986, 1988 Free Software Foundation, Inc.

		       NO WARRANTY

  BECAUSE THIS PROGRAM IS LICENSED FREE OF CHARGE, WE PROVIDE ABSOLUTELY
NO WARRANTY, TO THE EXTENT PERMITTED BY APPLICABLE STATE LAW.  EXCEPT
WHEN OTHERWISE STATED IN WRITING, FREE SOFTWARE FOUNDATION, INC,
RICHARD M. STALLMAN AND/OR OTHER PARTIES PROVIDE THIS PROGRAM "AS IS"
WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY
AND PERFORMANCE OF THE PROGRAM IS WITH YOU.  SHOULD THE PROGRAM PROVE
DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR
CORRECTION.

 IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW WILL RICHARD M.
STALLMAN, THE FREE SOFTWARE FOUNDATION, INC., AND/OR ANY OTHER PARTY
WHO MAY MODIFY AND REDISTRIBUTE THIS PROGRAM AS PERMITTED BELOW, BE
LIABLE TO YOU FOR DAMAGES, INCLUDING ANY LOST PROFITS, LOST MONIES, OR
OTHER SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
USE OR INABILITY TO USE (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR
DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY THIRD PARTIES OR
A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS) THIS
PROGRAM, EVEN IF YOU HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES, OR FOR ANY CLAIM BY ANY OTHER PARTY.

		GENERAL PUBLIC LICENSE TO COPY

  1. You may copy and distribute verbatim copies of this source file
as you receive it, in any medium, provided that you conspicuously and
appropriately publish on each copy a valid copyright notice "Copyright
(C) 1988 Free Software Foundation, Inc."; and include following the
copyright notice a verbatim copy of the above disclaimer of warranty
and of this License.  You may charge a distribution fee for the
physical act of transferring a copy.

  2. You may modify your copy or copies of this source file or
any portion of it, and copy and distribute such modifications under
the terms of Paragraph 1 above, provided that you also do the following:

    a) cause the modified files to carry prominent notices stating
    that you changed the files and the date of any change; and

    b) cause the whole of any work that you distribute or publish,
    that in whole or in part contains or is a derivative of this
    program or any part thereof, to be licensed at no charge to all
    third parties on terms identical to those contained in this
    License Agreement (except that you may choose to grant more extensive
    warranty protection to some or all third parties, at your option).

    c) You may charge a distribution fee for the physical act of
    transferring a copy, and you may at your option offer warranty
    protection in exchange for a fee.

Mere aggregation of another unrelated program with this program (or its
derivative) on a volume of a storage or distribution medium does not bring
the other program under the scope of these terms.

  3. You may copy and distribute this program (or a portion or derivative
of it, under Paragraph 2) in object code or executable form under the terms
of Paragraphs 1 and 2 above provided that you also do one of the following:

    a) accompany it with the complete corresponding machine-readable
    source code, which must be distributed under the terms of
    Paragraphs 1 and 2 above; or,

    b) accompany it with a written offer, valid for at least three
    years, to give any third party free (except for a nominal
    shipping charge) a complete machine-readable copy of the
    corresponding source code, to be distributed under the terms of
    Paragraphs 1 and 2 above; or,

    c) accompany it with the information you received as to where the
    corresponding source code may be obtained.  (This alternative is
    allowed only for noncommercial distribution and only if you
    received the program in object code or executable form alone.)

For an executable file, complete source code means all the source code for
all modules it contains; but, as a special exception, it need not include
source code for modules which are standard libraries that accompany the
operating system on which the executable file runs.

  4. You may not copy, sublicense, distribute or transfer this program
except as expressly provided under this License Agreement.  Any attempt
otherwise to copy, sublicense, distribute or transfer this program is void and
your rights to use the program under this License agreement shall be
automatically terminated.  However, parties who have received computer
software programs from you with this License Agreement will not have
their licenses terminated so long as such parties remain in full compliance.

  5. If you wish to incorporate parts of this program into other free
programs whose distribution conditions are different, write to the Free
Software Foundation at 675 Mass Ave, Cambridge, MA 02139.  We have not yet
worked out a simple rule that can be stated here, but we will often permit
this.  We will be guided by the two goals of preserving the free status of
all derivatives our free software and of promoting the sharing and reuse of
software.


In other words, you are welcome to use, share and improve this program.
You are forbidden to forbid anyone else to use, share and improve
what you give them.   Help stamp out software-hoarding!  */


/* Summary:

All the apparent functions defined here are macros. The idea
is that you would use these pre-tested macros to solve a
very specific set of problems, and they would run fast.
Caution: no side-effects in arguments please!! They may be
evaluated MANY times!!

These macros operate a stack of objects.  Each object starts life
small, and may grow to maturity.  (Consider building a word syllable
by syllable.)  An object can move while it is growing.  Once it has
been "finished" it never changes address again.  So the "top of the
stack" is typically an immature growing object, while the rest of the
stack is of mature, fixed size and fixed address objects.

These routines grab large chunks of memory, using a function you
supply, called `obstack_chunk_alloc'.  On occasion, they free chunks,
by calling `obstack_chunk_free'.  You must define them and declare
them before using any obstack macros.

Each independent stack is represented by a `struct obstack'.
Each of the obstack macros expects a pointer to such a structure
as the first argument.

One motivation for this package is the problem of growing char strings
in symbol tables.  Unless you are "facist pig with a read-only mind"
[Gosper's immortal quote from HAKMEM item 154, out of context] you
would not like to put any arbitrary upper limit on the length of your
symbols.

In practice this often means you will build many short symbols and a
few long symbols.  At the time you are reading a symbol you don't know
how long it is.  One traditional method is to read a symbol into a
buffer, realloc()ating the buffer every time you try to read a symbol
that is longer than the buffer.  This is beaut, but you still will
want to copy the symbol from the buffer to a more permanent
symbol-table entry say about half the time.

With obstacks, you can work differently.  Use one obstack for all symbol
names.  As you read a symbol, grow the name in the obstack gradually.
When the name is complete, finalize it.  Then, if the symbol exists already,
free the newly read name.

The way we do this is to take a large chunk, allocating memory from
low addresses.  When you want to build a aymbol in the chunk you just
add chars above the current "high water mark" in the chunk.  When you
have finished adding chars, because you got to the end of the symbol,
you know how long the chars are, and you can create a new object.
Mostly the chars will not burst over the highest address of the chunk,
because you would typically expect a chunk to be (say) 100 times as
long as an average object.

In case that isn't clear, when we have enough chars to make up
the object, THEY ARE ALREADY CONTIGUOUS IN THE CHUNK (guaranteed)
so we just point to it where it lies.  No moving of chars is
needed and this is the second win: potentially long strings need
never be explicitly shuffled. Once an object is formed, it does not
change its address during its lifetime.

When the chars burst over a chunk boundary, we allocate a larger
chunk, and then copy the partly formed object from the end of the old
chunk to the beggining of the new larger chunk.  We then carry on
accreting characters to the end of the object as we normaly would.

A special macro is provided to add a single char at a time to a
growing object.  This allows the use of register variables, which
break the ordinary 'growth' macro.

Summary:
	We allocate large chunks.
	We carve out one object at a time from the current chunk.
	Once carved, an object never moves.
	We are free to append data of any size to the currently
	  growing object.
	Exactly one object is growing in an obstack at any one time.
	You can run one obstack per control block.
	You may have as many control blocks as you dare.
	Because of the way we do it, you can `unwind' a obstack
	  back to a previous state. (You may remove objects much
	  as you would with a stack.)
*/


/* Don't do the contents of this file more than once.  */

#ifndef __OBSTACKS__
#define __OBSTACKS__

#ifdef __STDC__

/* Do the function-declarations before defining the macros.  */

void obstack_init (struct obstack *obstack);

void * obstack_alloc (struct obstack *obstack, int size);

void * obstack_copy (struct obstack *obstack, void *address, int size);
void * obstack_copy0 (struct obstack *obstack, void *address, int size);

void obstack_free (struct obstack *obstack, void *block);

void obstack_blank (struct obstack *obstack, int size);

void obstack_grow (struct obstack *obstack, void *data, int size);
void obstack_grow0 (struct obstack *obstack, void *data, int size);

void obstack_1grow (struct obstack *obstack, int data_char);

void * obstack_finish (struct obstack *obstack);

int obstack_object_size (struct obstack *obstack);

int obstack_room (struct obstack *obstack);
void obstack_1grow_fast (struct obstack *obstack, int data_char);
void obstack_blank_fast (struct obstack *obstack, int size);

void * object_base (struct obstack *obstack);
void * object_next_free (struct obstack *obstack);
int obstack_alignment_mask (struct obstack *obstack);
int obstack_chunk_size (struct obstack *obstack);

#endif /* __STDC__ */

/* Non-ANSI C cannot really support alternative functions for these macros,
   so we do not declare them.  */

struct _obstack_chunk		/* Lives at front of each chunk. */
{
  char  *limit;			/* 1 past end of this chunk */
  struct _obstack_chunk *prev;	/* address of prior chunk or NULL */
  char	contents[4];		/* objects begin here */
};

struct obstack		/* control current object in current chunk */
{
  long	chunk_size;		/* preferred size to allocate chunks in */
  struct _obstack_chunk* chunk;	/* address of current struct obstack_chunk */
  char	*object_base;		/* address of object we are building */
  char	*next_free;		/* where to add next char to current object */
  char	*chunk_limit;		/* address of char after current chunk */
  int	temp;			/* Temporary for some macros.  */
  int   alignment_mask;		/* Mask of alignment for each object. */
  struct _obstack_chunk *(*chunkfun) (); /* User's fcn to allocate a chunk.  */
  void (*freefun) ();		/* User's function to free a chunk.  */
};

/* Pointer to beginning of object being allocated or to be allocated next.
   Note that this might not be the final address of the object
   because a new chunk might be needed to hold the final size.  */

#define obstack_base(h) ((h)->object_base)

/* Size for allocating ordinary chunks.  */

#define obstack_chunk_size(h) ((h)->chunk_size)

/* Pointer to next byte not yet allocated in current chunk.  */

#define obstack_next_free(h)	((h)->next_free)

/* Mask specifying low bits that should be clear in address of an object.  */

#define obstack_alignment_mask(h) ((h)->alignment_mask)

#define obstack_init(h) \
  _obstack_begin ((h), 4096 - 4, 4, obstack_chunk_alloc, obstack_chunk_free)

#define obstack_begin(h, size) \
  _obstack_begin ((h), (size), 4, obstack_chunk_alloc, obstack_chunk_free)

#define obstack_1grow_fast(h,achar) (*((h)->next_free)++ = achar)

#define obstack_blank_fast(h,n) ((h)->next_free += (n))

#if defined (__GNU__) && defined (__STDC__)

/* For GNU C we can define these macros to compute all args only once
   without using a global variable.
   Also, we can avoid using the `temp' slot, to make faster code.

   By checking both __GNU__ and __STDC__, we can make sure
   both GNU language extensions and ANSI preprocessing are available.  */

#define obstack_object_size(OBSTACK)					\
  ({ struct obstack *__o = (OBSTACK);					\
     (unsigned) (__o->next_free - __o->object_base); })

#define obstack_room(OBSTACK)						\
  ({ struct obstack *__o = (OBSTACK);					\
     (unsigned) (__o->chunk_limit - __o->next_free); })

#define obstack_grow(OBSTACK,where,length)				\
({ struct obstack *__o = (OBSTACK);					\
   int __len = (length);						\
   ((__o->next_free + __len > __o->chunk_limit)				\
    ? _obstack_newchunk (__o, __len) : 0);				\
   bcopy (where, __o->next_free, __len);				\
   __o->next_free += __len;						\
   (void) 0; })

#define obstack_grow0(OBSTACK,where,length)				\
({ struct obstack *__o = (OBSTACK);					\
   int __len = (length);						\
   ((__o->next_free + __len + 1 > __o->chunk_limit)			\
    ? _obstack_newchunk (__o, __len + 1) : 0),				\
   bcopy (where, __o->next_free, __len),				\
   __o->next_free += __len,						\
   *(__o->next_free)++ = 0;						\
   (void) 0; })

#define obstack_1grow(OBSTACK,datum)					\
({ struct obstack *__o = (OBSTACK);					\
   ((__o->next_free + 1 > __o->chunk_limit)				\
    ? _obstack_newchunk (__o, 1) : 0),					\
   *(__o->next_free)++ = (datum);					\
   (void) 0; })

#define obstack_blank(OBSTACK,length)					\
({ struct obstack *__o = (OBSTACK);					\
   int __len = (length);						\
   ((__o->next_free + __len > __o->chunk_limit)				\
    ? _obstack_newchunk (__o, __len) : 0);				\
   __o->next_free += __len;						\
   (void) 0; })

#define obstack_alloc(OBSTACK,length)					\
({ struct obstack *__h = (OBSTACK);					\
   obstack_blank (__h, (length));					\
   obstack_finish (__h); })

#define obstack_copy(OBSTACK,where,length)				\
({ struct obstack *__h = (OBSTACK);					\
   obstack_grow (__h, (where), (length));				\
   obstack_finish (__h); })

#define obstack_copy0(OBSTACK,where,length)				\
({ struct obstack *__h = (OBSTACK);					\
   obstack_grow0 (__h, (where), (length));				\
   obstack_finish (__h); })

#define obstack_finish(OBSTACK)  					\
({ struct obstack *__o = (OBSTACK);					\
   void *value = (void *) __o->object_base;				\
   __o->next_free							\
     = (char*)((int)(__o->next_free+__o->alignment_mask)		\
	       & ~ (__o->alignment_mask));				\
   ((__o->next_free - (char *)__o->chunk				\
     > __o->chunk_limit - (char *)__o->chunk)				\
    ? __o->next_free = __o->chunk_limit : 0);				\
   __o->object_base = __o->next_free;					\
   value; })

#define obstack_free(OBSTACK, OBJ)					\
({ struct obstack *__o = (OBSTACK);					\
   void *__obj = (OBJ);							\
   if (__obj >= (void *)__o->chunk && __obj < (void *)__o->chunk_limit) \
     __o->next_free = __o->object_base = __obj;				\
   else (obstack_free) (__o, __obj); })

#else /* not __GNU__ */

/* The non-GNU macros copy the obstack-pointer into this global variable
   to avoid multiple evaluation.  */

extern struct obstack *_obstack;

#define obstack_object_size(h) \
 (unsigned) (_obstack = (h), (h)->next_free - (h)->object_base)

#define obstack_room(h)		\
 (unsigned) (_obstack = (h), (h)->chunk_limit - (h)->next_free)

#define obstack_grow(h,where,length)					\
( (h)->temp = (length),							\
  (((h)->next_free + (h)->temp > (h)->chunk_limit)			\
   ? _obstack_newchunk ((h), (h)->temp) : 0),				\
  bcopy (where, (h)->next_free, (h)->temp),				\
  (h)->next_free += (h)->temp)

#define obstack_grow0(h,where,length)					\
( (h)->temp = (length),							\
  (((h)->next_free + (h)->temp + 1 > (h)->chunk_limit)			\
   ? _obstack_newchunk ((h), (h)->temp + 1) : 0),				\
  bcopy (where, (h)->next_free, (h)->temp),				\
  (h)->next_free += (h)->temp,						\
  *((h)->next_free)++ = 0)

#define obstack_1grow(h,datum)						\
( (((h)->next_free + 1 > (h)->chunk_limit)				\
   ? _obstack_newchunk ((h), 1) : 0),					\
  *((h)->next_free)++ = (datum))

#define obstack_blank(h,length)						\
( (h)->temp = (length),							\
  (((h)->next_free + (h)->temp > (h)->chunk_limit)			\
   ? _obstack_newchunk ((h), (h)->temp) : 0),				\
  (h)->next_free += (h)->temp)

#define obstack_alloc(h,length)						\
 (obstack_blank ((h), (length)), obstack_finish ((h)))

#define obstack_copy(h,where,length)					\
 (obstack_grow ((h), (where), (length)), obstack_finish ((h)))

#define obstack_copy0(h,where,length)					\
 (obstack_grow0 ((h), (where), (length)), obstack_finish ((h)))

#define obstack_finish(h)  						\
( (h)->temp = (int) (h)->object_base,					\
  (h)->next_free							\
    = (char*)((int)((h)->next_free+(h)->alignment_mask)			\
	      & ~ ((h)->alignment_mask)),				\
  (((h)->next_free - (char *)(h)->chunk					\
    > (h)->chunk_limit - (char *)(h)->chunk)				\
   ? (h)->next_free = (h)->chunk_limit : 0),				\
  (h)->object_base = (h)->next_free,					\
  (char *) (h)->temp)

#ifdef __STDC__
#define obstack_free(h,obj)						\
( (h)->temp = (char *)(obj) - (char *) (h)->chunk,			\
  (((h)->temp >= 0 && (h)->temp < (h)->chunk_limit - (char *) (h)->chunk)\
   ? (int) ((h)->next_free = (h)->object_base				\
	    = (h)->temp + (char *) (h)->chunk)				\
   : (int) (obstack_free) ((h), (h)->temp + (char *) (h)->chunk)))
#else
#define obstack_free(h,obj)						\
( (h)->temp = (char *)(obj) - (char *) (h)->chunk,			\
  (((h)->temp >= 0 && (h)->temp < (h)->chunk_limit - (char *) (h)->chunk)\
   ? (int) ((h)->next_free = (h)->object_base				\
	    = (h)->temp + (char *) (h)->chunk)				\
   : (int) _obstack_free ((h), (h)->temp + (char *) (h)->chunk)))
#endif

#endif /* not __GNU__ */

#endif /* not __OBSTACKS__ */