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1.1 root 1: /* obstack.h - object stack macros
2: Copyright (C) 1988 Free Software Foundation, Inc.
3:
4: NO WARRANTY
5:
6: BECAUSE THIS PROGRAM IS LICENSED FREE OF CHARGE, WE PROVIDE ABSOLUTELY
7: NO WARRANTY, TO THE EXTENT PERMITTED BY APPLICABLE STATE LAW. EXCEPT
8: WHEN OTHERWISE STATED IN WRITING, FREE SOFTWARE FOUNDATION, INC,
9: RICHARD M. STALLMAN AND/OR OTHER PARTIES PROVIDE THIS PROGRAM "AS IS"
10: WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
11: BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
12: FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY
13: AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE
14: DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR
15: CORRECTION.
16:
17: IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW WILL RICHARD M.
18: STALLMAN, THE FREE SOFTWARE FOUNDATION, INC., AND/OR ANY OTHER PARTY
19: WHO MAY MODIFY AND REDISTRIBUTE THIS PROGRAM AS PERMITTED BELOW, BE
20: LIABLE TO YOU FOR DAMAGES, INCLUDING ANY LOST PROFITS, LOST MONIES, OR
21: OTHER SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
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24: A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS) THIS
25: PROGRAM, EVEN IF YOU HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH
26: DAMAGES, OR FOR ANY CLAIM BY ANY OTHER PARTY.
27:
28: GENERAL PUBLIC LICENSE TO COPY
29:
30: 1. You may copy and distribute verbatim copies of this source file
31: as you receive it, in any medium, provided that you conspicuously and
32: appropriately publish on each copy a valid copyright notice "Copyright
33: (C) 1988 Free Software Foundation, Inc."; and include following the
34: copyright notice a verbatim copy of the above disclaimer of warranty
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36: physical act of transferring a copy.
37:
38: 2. You may modify your copy or copies of this source file or
39: any portion of it, and copy and distribute such modifications under
40: the terms of Paragraph 1 above, provided that you also do the following:
41:
42: a) cause the modified files to carry prominent notices stating
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44:
45: b) cause the whole of any work that you distribute or publish,
46: that in whole or in part contains or is a derivative of this
47: program or any part thereof, to be licensed at no charge to all
48: third parties on terms identical to those contained in this
49: License Agreement (except that you may choose to grant more extensive
50: warranty protection to some or all third parties, at your option).
51:
52: c) You may charge a distribution fee for the physical act of
53: transferring a copy, and you may at your option offer warranty
54: protection in exchange for a fee.
55:
56: Mere aggregation of another unrelated program with this program (or its
57: derivative) on a volume of a storage or distribution medium does not bring
58: the other program under the scope of these terms.
59:
60: 3. You may copy and distribute this program or any portion of it in
61: compiled, executable or object code form under the terms of Paragraphs
62: 1 and 2 above provided that you do the following:
63:
64: a) accompany it with the complete corresponding machine-readable
65: source code, which must be distributed under the terms of
66: Paragraphs 1 and 2 above; or,
67:
68: b) accompany it with a written offer, valid for at least three
69: years, to give any third party free (except for a nominal
70: shipping charge) a complete machine-readable copy of the
71: corresponding source code, to be distributed under the terms of
72: Paragraphs 1 and 2 above; or,
73:
74: c) accompany it with the information you received as to where the
75: corresponding source code may be obtained. (This alternative is
76: allowed only for noncommercial distribution and only if you
77: received the program in object code or executable form alone.)
78:
79: For an executable file, complete source code means all the source code for
80: all modules it contains; but, as a special exception, it need not include
81: source code for modules which are standard libraries that accompany the
82: operating system on which the executable file runs.
83:
84: 4. You may not copy, sublicense, distribute or transfer this program
85: except as expressly provided under this License Agreement. Any attempt
86: otherwise to copy, sublicense, distribute or transfer this program is void and
87: your rights to use the program under this License agreement shall be
88: automatically terminated. However, parties who have received computer
89: software programs from you with this License Agreement will not have
90: their licenses terminated so long as such parties remain in full compliance.
91:
92: 5. If you wish to incorporate parts of this program into other free
93: programs whose distribution conditions are different, write to the Free
94: Software Foundation at 675 Mass Ave, Cambridge, MA 02139. We have not yet
95: worked out a simple rule that can be stated here, but we will often permit
96: this. We will be guided by the two goals of preserving the free status of
97: all derivatives our free software and of promoting the sharing and reuse of
98: software.
99:
100:
101: In other words, you are welcome to use, share and improve this program.
102: You are forbidden to forbid anyone else to use, share and improve
103: what you give them. Help stamp out software-hoarding! */
104:
105:
106: /* Summary:
107:
108: All the apparent functions defined here are macros. The idea
109: is that you would use these pre-tested macros to solve a
110: very specific set of problems, and they would run fast.
111: Caution: no side-effects in arguments please!! They may be
112: evaluated MANY times!!
113:
114: These macros operate a stack of objects. Each object starts life
115: small, and may grow to maturity. (Consider building a word syllable
116: by syllable.) An object can move while it is growing. Once it has
117: been "finished" it never changes address again. So the "top of the
118: stack" is typically an immature growing object, while the rest of the
119: stack is of mature, fixed size and fixed address objects.
120:
121: These routines grab large chunks of memory, using a function you
122: supply, called `obstack_chunk_alloc'. On occasion, they free chunks,
123: by calling `obstack_chunk_free'. You must define them and declare
124: them before using any obstack macros.
125:
126: Each independent stack is represented by a `struct obstack'.
127: Each of the obstack macros expects a pointer to such a structure
128: as the first argument.
129:
130: One motivation for this package is the problem of growing char strings
131: in symbol tables. Unless you are "facist pig with a read-only mind"
132: [Gosper's immortal quote from HAKMEM item 154, out of context] you
133: would not like to put any arbitrary upper limit on the length of your
134: symbols.
135:
136: In practice this often means you will build many short symbols and a
137: few long symbols. At the time you are reading a symbol you don't know
138: how long it is. One traditional method is to read a symbol into a
139: buffer, realloc()ating the buffer every time you try to read a symbol
140: that is longer than the buffer. This is beaut, but you still will
141: want to copy the symbol from the buffer to a more permanent
142: symbol-table entry say about half the time.
143:
144: With obstacks, you can work differently. Use one obstack for all symbol
145: names. As you read a symbol, grow the name in the obstack gradually.
146: When the name is complete, finalize it. Then, if the symbol exists already,
147: free the newly read name.
148:
149: The way we do this is to take a large chunk, allocating memory from
150: low addresses. When you want to build a aymbol in the chunk you just
151: add chars above the current "high water mark" in the chunk. When you
152: have finished adding chars, because you got to the end of the symbol,
153: you know how long the chars are, and you can create a new object.
154: Mostly the chars will not burst over the highest address of the chunk,
155: because you would typically expect a chunk to be (say) 100 times as
156: long as an average object.
157:
158: In case that isn't clear, when we have enough chars to make up
159: the object, THEY ARE ALREADY CONTIGUOUS IN THE CHUNK (guaranteed)
160: so we just point to it where it lies. No moving of chars is
161: needed and this is the second win: potentially long strings need
162: never be explicitly shuffled. Once an object is formed, it does not
163: change its address during its lifetime.
164:
165: When the chars burst over a chunk boundary, we allocate a larger
166: chunk, and then copy the partly formed object from the end of the old
167: chunk to the beggining of the new larger chunk. We then carry on
168: accreting characters to the end of the object as we normaly would.
169:
170: A special macro is provided to add a single char at a time to a
171: growing object. This allows the use of register variables, which
172: break the ordinary 'growth' macro.
173:
174: Summary:
175: We allocate large chunks.
176: We carve out one object at a time from the current chunk.
177: Once carved, an object never moves.
178: We are free to append data of any size to the currently
179: growing object.
180: Exactly one object is growing in an obstack at any one time.
181: You can run one obstack per control block.
182: You may have as many control blocks as you dare.
183: Because of the way we do it, you can `unwind' a obstack
184: back to a previous state. (You may remove objects much
185: as you would with a stack.)
186: */
187:
188:
189: /* Don't do the contents of this file more than once. */
190:
191: #ifndef __OBSTACKS__
192: #define __OBSTACKS__
193:
194: struct _obstack_chunk /* Lives at front of each chunk. */
195: {
196: char *limit; /* 1 past end of this chunk */
197: struct _obstack_chunk *prev; /* address of prior chunk or NULL */
198: char contents[4]; /* objects begin here */
199: };
200:
201: struct obstack /* control current object in current chunk */
202: {
203: long chunk_size; /* preferred size to allocate chunks in */
204: struct _obstack_chunk* chunk; /* address of current struct obstack_chunk */
205: char *object_base; /* address of object we are building */
206: char *next_free; /* where to add next char to current object */
207: char *chunk_limit; /* address of char after current chunk */
208: int temp; /* Temporary for some macros. */
209: int alignment_mask; /* Mask of alignment for each object. */
210: struct _obstack_chunk *(*chunkfun) (); /* User's fcn to allocate a chunk. */
211: void (*freefun) (); /* User's function to free a chunk. */
212: };
213:
214: #ifdef __STDC__
215:
216: /* Do the function-declarations after the structs
217: but before defining the macros. */
218:
219: void obstack_init (struct obstack *obstack);
220:
221: void * obstack_alloc (struct obstack *obstack, int size);
222:
223: void * obstack_copy (struct obstack *obstack, void *address, int size);
224: void * obstack_copy0 (struct obstack *obstack, void *address, int size);
225:
226: void obstack_free (struct obstack *obstack, void *block);
227:
228: void obstack_blank (struct obstack *obstack, int size);
229:
230: void obstack_grow (struct obstack *obstack, void *data, int size);
231: void obstack_grow0 (struct obstack *obstack, void *data, int size);
232:
233: void obstack_1grow (struct obstack *obstack, int data_char);
234:
235: void * obstack_finish (struct obstack *obstack);
236:
237: int obstack_object_size (struct obstack *obstack);
238:
239: int obstack_room (struct obstack *obstack);
240: void obstack_1grow_fast (struct obstack *obstack, int data_char);
241: void obstack_blank_fast (struct obstack *obstack, int size);
242:
243: void * obstack_base (struct obstack *obstack);
244: void * obstack_next_free (struct obstack *obstack);
245: int obstack_alignment_mask (struct obstack *obstack);
246: int obstack_chunk_size (struct obstack *obstack);
247:
248: #endif /* __STDC__ */
249:
250: /* Non-ANSI C cannot really support alternative functions for these macros,
251: so we do not declare them. */
252:
253: /* Pointer to beginning of object being allocated or to be allocated next.
254: Note that this might not be the final address of the object
255: because a new chunk might be needed to hold the final size. */
256:
257: #define obstack_base(h) ((h)->object_base)
258:
259: /* Size for allocating ordinary chunks. */
260:
261: #define obstack_chunk_size(h) ((h)->chunk_size)
262:
263: /* Pointer to next byte not yet allocated in current chunk. */
264:
265: #define obstack_next_free(h) ((h)->next_free)
266:
267: /* Mask specifying low bits that should be clear in address of an object. */
268:
269: #define obstack_alignment_mask(h) ((h)->alignment_mask)
270:
271: #define obstack_init(h) \
272: _obstack_begin ((h), 4096 - 4, 0, obstack_chunk_alloc, obstack_chunk_free)
273:
274: #define obstack_begin(h, size) \
275: _obstack_begin ((h), (size), 0, obstack_chunk_alloc, obstack_chunk_free)
276:
277: #define obstack_1grow_fast(h,achar) (*((h)->next_free)++ = achar)
278:
279: #define obstack_blank_fast(h,n) ((h)->next_free += (n))
280:
281: #ifdef __GNUC__
282:
283: /* For GNU C we can define these macros to compute all args only once
284: without using a global variable.
285: Also, we can avoid using the `temp' slot, to make faster code. */
286:
287: #define obstack_object_size(OBSTACK) \
288: ({ struct obstack *__o = (OBSTACK); \
289: (unsigned) (__o->next_free - __o->object_base); })
290:
291: #define obstack_room(OBSTACK) \
292: ({ struct obstack *__o = (OBSTACK); \
293: (unsigned) (__o->chunk_limit - __o->next_free); })
294:
295: #define obstack_grow(OBSTACK,where,length) \
296: ({ struct obstack *__o = (OBSTACK); \
297: int __len = (length); \
298: ((__o->next_free + __len > __o->chunk_limit) \
299: ? _obstack_newchunk (__o, __len) : 0); \
300: bcopy (where, __o->next_free, __len); \
301: __o->next_free += __len; \
302: (void) 0; })
303:
304: #define obstack_grow0(OBSTACK,where,length) \
305: ({ struct obstack *__o = (OBSTACK); \
306: int __len = (length); \
307: ((__o->next_free + __len + 1 > __o->chunk_limit) \
308: ? _obstack_newchunk (__o, __len + 1) : 0), \
309: bcopy (where, __o->next_free, __len), \
310: __o->next_free += __len, \
311: *(__o->next_free)++ = 0; \
312: (void) 0; })
313:
314: #define obstack_1grow(OBSTACK,datum) \
315: ({ struct obstack *__o = (OBSTACK); \
316: ((__o->next_free + 1 > __o->chunk_limit) \
317: ? _obstack_newchunk (__o, 1) : 0), \
318: *(__o->next_free)++ = (datum); \
319: (void) 0; })
320:
321: #define obstack_blank(OBSTACK,length) \
322: ({ struct obstack *__o = (OBSTACK); \
323: int __len = (length); \
324: ((__o->next_free + __len > __o->chunk_limit) \
325: ? _obstack_newchunk (__o, __len) : 0); \
326: __o->next_free += __len; \
327: (void) 0; })
328:
329: #define obstack_alloc(OBSTACK,length) \
330: ({ struct obstack *__h = (OBSTACK); \
331: obstack_blank (__h, (length)); \
332: obstack_finish (__h); })
333:
334: #define obstack_copy(OBSTACK,where,length) \
335: ({ struct obstack *__h = (OBSTACK); \
336: obstack_grow (__h, (where), (length)); \
337: obstack_finish (__h); })
338:
339: #define obstack_copy0(OBSTACK,where,length) \
340: ({ struct obstack *__h = (OBSTACK); \
341: obstack_grow0 (__h, (where), (length)); \
342: obstack_finish (__h); })
343:
344: #define obstack_finish(OBSTACK) \
345: ({ struct obstack *__o = (OBSTACK); \
346: void *value = (void *) __o->object_base; \
347: __o->next_free \
348: = (char*)((int)(__o->next_free+__o->alignment_mask) \
349: & ~ (__o->alignment_mask)); \
350: ((__o->next_free - (char *)__o->chunk \
351: > __o->chunk_limit - (char *)__o->chunk) \
352: ? __o->next_free = __o->chunk_limit : 0); \
353: __o->object_base = __o->next_free; \
354: value; })
355:
356: #define obstack_free(OBSTACK, OBJ) \
357: ({ struct obstack *__o = (OBSTACK); \
358: void *__obj = (OBJ); \
359: if (__obj >= (void *)__o->chunk && __obj < (void *)__o->chunk_limit) \
360: __o->next_free = __o->object_base = __obj; \
361: else (obstack_free) (__o, __obj); })
362:
363: #else /* not __GNUC__ */
364:
365: /* The non-GNU macros copy the obstack-pointer into this global variable
366: to avoid multiple evaluation. */
367:
368: extern struct obstack *_obstack;
369:
370: #define obstack_object_size(h) \
371: (unsigned) (_obstack = (h), (h)->next_free - (h)->object_base)
372:
373: #define obstack_room(h) \
374: (unsigned) (_obstack = (h), (h)->chunk_limit - (h)->next_free)
375:
376: #define obstack_grow(h,where,length) \
377: ( (h)->temp = (length), \
378: (((h)->next_free + (h)->temp > (h)->chunk_limit) \
379: ? _obstack_newchunk ((h), (h)->temp) : 0), \
380: bcopy (where, (h)->next_free, (h)->temp), \
381: (h)->next_free += (h)->temp)
382:
383: #define obstack_grow0(h,where,length) \
384: ( (h)->temp = (length), \
385: (((h)->next_free + (h)->temp + 1 > (h)->chunk_limit) \
386: ? _obstack_newchunk ((h), (h)->temp + 1) : 0), \
387: bcopy (where, (h)->next_free, (h)->temp), \
388: (h)->next_free += (h)->temp, \
389: *((h)->next_free)++ = 0)
390:
391: #define obstack_1grow(h,datum) \
392: ( (((h)->next_free + 1 > (h)->chunk_limit) \
393: ? _obstack_newchunk ((h), 1) : 0), \
394: *((h)->next_free)++ = (datum))
395:
396: #define obstack_blank(h,length) \
397: ( (h)->temp = (length), \
398: (((h)->next_free + (h)->temp > (h)->chunk_limit) \
399: ? _obstack_newchunk ((h), (h)->temp) : 0), \
400: (h)->next_free += (h)->temp)
401:
402: #define obstack_alloc(h,length) \
403: (obstack_blank ((h), (length)), obstack_finish ((h)))
404:
405: #define obstack_copy(h,where,length) \
406: (obstack_grow ((h), (where), (length)), obstack_finish ((h)))
407:
408: #define obstack_copy0(h,where,length) \
409: (obstack_grow0 ((h), (where), (length)), obstack_finish ((h)))
410:
411: #define obstack_finish(h) \
412: ( (h)->temp = (int) (h)->object_base, \
413: (h)->next_free \
414: = (char*)((int)((h)->next_free+(h)->alignment_mask) \
415: & ~ ((h)->alignment_mask)), \
416: (((h)->next_free - (char *)(h)->chunk \
417: > (h)->chunk_limit - (char *)(h)->chunk) \
418: ? ((h)->next_free = (h)->chunk_limit) : 0), \
419: (h)->object_base = (h)->next_free, \
420: (char *) (h)->temp)
421:
422: #ifdef __STDC__
423: #define obstack_free(h,obj) \
424: ( (h)->temp = (char *)(obj) - (char *) (h)->chunk, \
425: (((h)->temp >= 0 && (h)->temp < (h)->chunk_limit - (char *) (h)->chunk)\
426: ? (int) ((h)->next_free = (h)->object_base \
427: = (h)->temp + (char *) (h)->chunk) \
428: : ((obstack_free) ((h), (h)->temp + (char *) (h)->chunk), 0)))
429: #else
430: #define obstack_free(h,obj) \
431: ( (h)->temp = (char *)(obj) - (char *) (h)->chunk, \
432: (((h)->temp >= 0 && (h)->temp < (h)->chunk_limit - (char *) (h)->chunk)\
433: ? (int) ((h)->next_free = (h)->object_base \
434: = (h)->temp + (char *) (h)->chunk) \
435: : (int) _obstack_free ((h), (h)->temp + (char *) (h)->chunk)))
436: #endif
437:
438: #endif /* not __GNUC__ */
439:
440: #endif /* not __OBSTACKS__ */
441:
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