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1.1     ! root        1: /* obstack.h - 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: /* Summary:
        !            19: 
        !            20: All the apparent functions defined here are macros. The idea
        !            21: is that you would use these pre-tested macros to solve a
        !            22: very specific set of problems, and they would run fast.
        !            23: Caution: no side-effects in arguments please!! They may be
        !            24: evaluated MANY times!!
        !            25: 
        !            26: These macros operate a stack of objects.  Each object starts life
        !            27: small, and may grow to maturity.  (Consider building a word syllable
        !            28: by syllable.)  An object can move while it is growing.  Once it has
        !            29: been "finished" it never changes address again.  So the "top of the
        !            30: stack" is typically an immature growing object, while the rest of the
        !            31: stack is of mature, fixed size and fixed address objects.
        !            32: 
        !            33: These routines grab large chunks of memory, using a function you
        !            34: supply, called `obstack_chunk_alloc'.  On occasion, they free chunks,
        !            35: by calling `obstack_chunk_free'.  You must define them and declare
        !            36: them before using any obstack macros.
        !            37: 
        !            38: Each independent stack is represented by a `struct obstack'.
        !            39: Each of the obstack macros expects a pointer to such a structure
        !            40: as the first argument.
        !            41: 
        !            42: One motivation for this package is the problem of growing char strings
        !            43: in symbol tables.  Unless you are "fascist pig with a read-only mind"
        !            44: [Gosper's immortal quote from HAKMEM item 154, out of context] you
        !            45: would not like to put any arbitrary upper limit on the length of your
        !            46: symbols.
        !            47: 
        !            48: In practice this often means you will build many short symbols and a
        !            49: few long symbols.  At the time you are reading a symbol you don't know
        !            50: how long it is.  One traditional method is to read a symbol into a
        !            51: buffer, realloc()ating the buffer every time you try to read a symbol
        !            52: that is longer than the buffer.  This is beaut, but you still will
        !            53: want to copy the symbol from the buffer to a more permanent
        !            54: symbol-table entry say about half the time.
        !            55: 
        !            56: With obstacks, you can work differently.  Use one obstack for all symbol
        !            57: names.  As you read a symbol, grow the name in the obstack gradually.
        !            58: When the name is complete, finalize it.  Then, if the symbol exists already,
        !            59: free the newly read name.
        !            60: 
        !            61: The way we do this is to take a large chunk, allocating memory from
        !            62: low addresses.  When you want to build a symbol in the chunk you just
        !            63: add chars above the current "high water mark" in the chunk.  When you
        !            64: have finished adding chars, because you got to the end of the symbol,
        !            65: you know how long the chars are, and you can create a new object.
        !            66: Mostly the chars will not burst over the highest address of the chunk,
        !            67: because you would typically expect a chunk to be (say) 100 times as
        !            68: long as an average object.
        !            69: 
        !            70: In case that isn't clear, when we have enough chars to make up
        !            71: the object, THEY ARE ALREADY CONTIGUOUS IN THE CHUNK (guaranteed)
        !            72: so we just point to it where it lies.  No moving of chars is
        !            73: needed and this is the second win: potentially long strings need
        !            74: never be explicitly shuffled. Once an object is formed, it does not
        !            75: change its address during its lifetime.
        !            76: 
        !            77: When the chars burst over a chunk boundary, we allocate a larger
        !            78: chunk, and then copy the partly formed object from the end of the old
        !            79: chunk to the beginning of the new larger chunk.  We then carry on
        !            80: accreting characters to the end of the object as we normally would.
        !            81: 
        !            82: A special macro is provided to add a single char at a time to a
        !            83: growing object.  This allows the use of register variables, which
        !            84: break the ordinary 'growth' macro.
        !            85: 
        !            86: Summary:
        !            87:        We allocate large chunks.
        !            88:        We carve out one object at a time from the current chunk.
        !            89:        Once carved, an object never moves.
        !            90:        We are free to append data of any size to the currently
        !            91:          growing object.
        !            92:        Exactly one object is growing in an obstack at any one time.
        !            93:        You can run one obstack per control block.
        !            94:        You may have as many control blocks as you dare.
        !            95:        Because of the way we do it, you can `unwind' a obstack
        !            96:          back to a previous state. (You may remove objects much
        !            97:          as you would with a stack.)
        !            98: */
        !            99: 
        !           100: 
        !           101: /* Don't do the contents of this file more than once.  */
        !           102: 
        !           103: #ifndef __OBSTACKS__
        !           104: #define __OBSTACKS__
        !           105: 
        !           106: /* We use subtraction of (char *)0 instead of casting to int
        !           107:    because on word-addressable machines a simple cast to int
        !           108:    may ignore the byte-within-word field of the pointer.  */
        !           109: 
        !           110: #ifndef __PTR_TO_INT
        !           111: #define __PTR_TO_INT(P) ((P) - (char *)0)
        !           112: #endif
        !           113: 
        !           114: #ifndef __INT_TO_PTR
        !           115: #define __INT_TO_PTR(P) ((P) + (char *)0)
        !           116: #endif
        !           117: 
        !           118: struct _obstack_chunk          /* Lives at front of each chunk. */
        !           119: {
        !           120:   char  *limit;                        /* 1 past end of this chunk */
        !           121:   struct _obstack_chunk *prev; /* address of prior chunk or NULL */
        !           122:   char contents[4];            /* objects begin here */
        !           123: };
        !           124: 
        !           125: struct obstack         /* control current object in current chunk */
        !           126: {
        !           127:   long chunk_size;             /* preferred size to allocate chunks in */
        !           128:   struct _obstack_chunk* chunk;        /* address of current struct obstack_chunk */
        !           129:   char *object_base;           /* address of object we are building */
        !           130:   char *next_free;             /* where to add next char to current object */
        !           131:   char *chunk_limit;           /* address of char after current chunk */
        !           132:   int  temp;                   /* Temporary for some macros.  */
        !           133:   int   alignment_mask;                /* Mask of alignment for each object. */
        !           134:   struct _obstack_chunk *(*chunkfun) (); /* User's fcn to allocate a chunk.  */
        !           135:   void (*freefun) ();          /* User's function to free a chunk.  */
        !           136:   /* Nonzero means there is a possibility the current chunk contains
        !           137:      a zero-length object.  This prevents freeing the chunk
        !           138:      if we allocate a bigger chunk to replace it.  */
        !           139:   char  maybe_empty_object;
        !           140: };
        !           141: 
        !           142: /* Declare the external functions we use; they are in obstack.c.  */
        !           143: 
        !           144: #ifdef __STDC__
        !           145: extern void _obstack_newchunk (struct obstack *, int);
        !           146: extern void _obstack_free (struct obstack *, void *);
        !           147: extern void _obstack_begin (struct obstack *, int, int,
        !           148:                            void *(*) (), void (*) ());
        !           149: #else
        !           150: extern void _obstack_newchunk ();
        !           151: extern void _obstack_free ();
        !           152: extern void _obstack_begin ();
        !           153: #endif
        !           154: 
        !           155: #ifdef __STDC__
        !           156: 
        !           157: /* Do the function-declarations after the structs
        !           158:    but before defining the macros.  */
        !           159: 
        !           160: void obstack_init (struct obstack *obstack);
        !           161: 
        !           162: void * obstack_alloc (struct obstack *obstack, int size);
        !           163: 
        !           164: void * obstack_copy (struct obstack *obstack, void *address, int size);
        !           165: void * obstack_copy0 (struct obstack *obstack, void *address, int size);
        !           166: 
        !           167: void obstack_free (struct obstack *obstack, void *block);
        !           168: 
        !           169: void obstack_blank (struct obstack *obstack, int size);
        !           170: 
        !           171: void obstack_grow (struct obstack *obstack, void *data, int size);
        !           172: void obstack_grow0 (struct obstack *obstack, void *data, int size);
        !           173: 
        !           174: void obstack_1grow (struct obstack *obstack, int data_char);
        !           175: void obstack_ptr_grow (struct obstack *obstack, void *data);
        !           176: void obstack_int_grow (struct obstack *obstack, int data);
        !           177: 
        !           178: void * obstack_finish (struct obstack *obstack);
        !           179: 
        !           180: int obstack_object_size (struct obstack *obstack);
        !           181: 
        !           182: int obstack_room (struct obstack *obstack);
        !           183: void obstack_1grow_fast (struct obstack *obstack, int data_char);
        !           184: void obstack_ptr_grow_fast (struct obstack *obstack, void *data);
        !           185: void obstack_int_grow_fast (struct obstack *obstack, int data);
        !           186: void obstack_blank_fast (struct obstack *obstack, int size);
        !           187: 
        !           188: void * obstack_base (struct obstack *obstack);
        !           189: void * obstack_next_free (struct obstack *obstack);
        !           190: int obstack_alignment_mask (struct obstack *obstack);
        !           191: int obstack_chunk_size (struct obstack *obstack);
        !           192: 
        !           193: #endif /* __STDC__ */
        !           194: 
        !           195: /* Non-ANSI C cannot really support alternative functions for these macros,
        !           196:    so we do not declare them.  */
        !           197: 
        !           198: /* Pointer to beginning of object being allocated or to be allocated next.
        !           199:    Note that this might not be the final address of the object
        !           200:    because a new chunk might be needed to hold the final size.  */
        !           201: 
        !           202: #define obstack_base(h) ((h)->object_base)
        !           203: 
        !           204: /* Size for allocating ordinary chunks.  */
        !           205: 
        !           206: #define obstack_chunk_size(h) ((h)->chunk_size)
        !           207: 
        !           208: /* Pointer to next byte not yet allocated in current chunk.  */
        !           209: 
        !           210: #define obstack_next_free(h)   ((h)->next_free)
        !           211: 
        !           212: /* Mask specifying low bits that should be clear in address of an object.  */
        !           213: 
        !           214: #define obstack_alignment_mask(h) ((h)->alignment_mask)
        !           215: 
        !           216: #define obstack_init(h) \
        !           217:   _obstack_begin ((h), 0, 0, \
        !           218:                  (void *(*) ()) obstack_chunk_alloc, obstack_chunk_free)
        !           219: 
        !           220: #define obstack_begin(h, size) \
        !           221:   _obstack_begin ((h), (size), 0, \
        !           222:                  (void *(*) ()) obstack_chunk_alloc, obstack_chunk_free)
        !           223: 
        !           224: #define obstack_1grow_fast(h,achar) (*((h)->next_free)++ = achar)
        !           225: 
        !           226: #define obstack_blank_fast(h,n) ((h)->next_free += (n))
        !           227: 
        !           228: #if defined (__GNUC__) && defined (__STDC__)
        !           229: #if __GNUC__ < 2
        !           230: #define __extension__
        !           231: #endif
        !           232: 
        !           233: /* For GNU C, if not -traditional,
        !           234:    we can define these macros to compute all args only once
        !           235:    without using a global variable.
        !           236:    Also, we can avoid using the `temp' slot, to make faster code.  */
        !           237: 
        !           238: #define obstack_object_size(OBSTACK)                                   \
        !           239:   __extension__                                                                \
        !           240:   ({ struct obstack *__o = (OBSTACK);                                  \
        !           241:      (unsigned) (__o->next_free - __o->object_base); })
        !           242: 
        !           243: #define obstack_room(OBSTACK)                                          \
        !           244:   __extension__                                                                \
        !           245:   ({ struct obstack *__o = (OBSTACK);                                  \
        !           246:      (unsigned) (__o->chunk_limit - __o->next_free); })
        !           247: 
        !           248: /* Note that the call to _obstack_newchunk is enclosed in (..., 0)
        !           249:    so that we can avoid having void expressions
        !           250:    in the arms of the conditional expression.
        !           251:    Casting the third operand to void was tried before,
        !           252:    but some compilers won't accept it.  */
        !           253: #define obstack_grow(OBSTACK,where,length)                             \
        !           254: __extension__                                                          \
        !           255: ({ struct obstack *__o = (OBSTACK);                                    \
        !           256:    int __len = (length);                                               \
        !           257:    ((__o->next_free + __len > __o->chunk_limit)                                \
        !           258:     ? (_obstack_newchunk (__o, __len), 0) : 0);                                \
        !           259:    bcopy (where, __o->next_free, __len);                               \
        !           260:    __o->next_free += __len;                                            \
        !           261:    (void) 0; })
        !           262: 
        !           263: #define obstack_grow0(OBSTACK,where,length)                            \
        !           264: __extension__                                                          \
        !           265: ({ struct obstack *__o = (OBSTACK);                                    \
        !           266:    int __len = (length);                                               \
        !           267:    ((__o->next_free + __len + 1 > __o->chunk_limit)                    \
        !           268:     ? (_obstack_newchunk (__o, __len + 1), 0) : 0),                    \
        !           269:    bcopy (where, __o->next_free, __len),                               \
        !           270:    __o->next_free += __len,                                            \
        !           271:    *(__o->next_free)++ = 0;                                            \
        !           272:    (void) 0; })
        !           273: 
        !           274: #define obstack_1grow(OBSTACK,datum)                                   \
        !           275: __extension__                                                          \
        !           276: ({ struct obstack *__o = (OBSTACK);                                    \
        !           277:    ((__o->next_free + 1 > __o->chunk_limit)                            \
        !           278:     ? (_obstack_newchunk (__o, 1), 0) : 0),                            \
        !           279:    *(__o->next_free)++ = (datum);                                      \
        !           280:    (void) 0; })
        !           281: 
        !           282: /* These assume that the obstack alignment is good enough for pointers or ints,
        !           283:    and that the data added so far to the current object
        !           284:    shares that much alignment.  */
        !           285:    
        !           286: #define obstack_ptr_grow(OBSTACK,datum)                                        \
        !           287: __extension__                                                          \
        !           288: ({ struct obstack *__o = (OBSTACK);                                    \
        !           289:    ((__o->next_free + sizeof (void *) > __o->chunk_limit)              \
        !           290:     ? (_obstack_newchunk (__o, sizeof (void *)), 0) : 0),              \
        !           291:    *((void **)__o->next_free)++ = ((void *)datum);                     \
        !           292:    (void) 0; })
        !           293: 
        !           294: #define obstack_int_grow(OBSTACK,datum)                                        \
        !           295: __extension__                                                          \
        !           296: ({ struct obstack *__o = (OBSTACK);                                    \
        !           297:    ((__o->next_free + sizeof (int) > __o->chunk_limit)                 \
        !           298:     ? (_obstack_newchunk (__o, sizeof (int)), 0) : 0),                 \
        !           299:    *((int *)__o->next_free)++ = ((int)datum);                          \
        !           300:    (void) 0; })
        !           301: 
        !           302: #define obstack_ptr_grow_fast(h,aptr) (*((void **)(h)->next_free)++ = (void *)aptr)
        !           303: #define obstack_int_grow_fast(h,aint) (*((int *)(h)->next_free)++ = (int)aint)
        !           304: 
        !           305: #define obstack_blank(OBSTACK,length)                                  \
        !           306: __extension__                                                          \
        !           307: ({ struct obstack *__o = (OBSTACK);                                    \
        !           308:    int __len = (length);                                               \
        !           309:    ((__o->chunk_limit - __o->next_free < __len)                                \
        !           310:     ? (_obstack_newchunk (__o, __len), 0) : 0);                                \
        !           311:    __o->next_free += __len;                                            \
        !           312:    (void) 0; })
        !           313: 
        !           314: #define obstack_alloc(OBSTACK,length)                                  \
        !           315: __extension__                                                          \
        !           316: ({ struct obstack *__h = (OBSTACK);                                    \
        !           317:    obstack_blank (__h, (length));                                      \
        !           318:    obstack_finish (__h); })
        !           319: 
        !           320: #define obstack_copy(OBSTACK,where,length)                             \
        !           321: __extension__                                                          \
        !           322: ({ struct obstack *__h = (OBSTACK);                                    \
        !           323:    obstack_grow (__h, (where), (length));                              \
        !           324:    obstack_finish (__h); })
        !           325: 
        !           326: #define obstack_copy0(OBSTACK,where,length)                            \
        !           327: __extension__                                                          \
        !           328: ({ struct obstack *__h = (OBSTACK);                                    \
        !           329:    obstack_grow0 (__h, (where), (length));                             \
        !           330:    obstack_finish (__h); })
        !           331: 
        !           332: /* The local variable is named __o1 to avoid a name conflict
        !           333:    when obstack_blank is called.  */
        !           334: #define obstack_finish(OBSTACK)                                        \
        !           335: __extension__                                                          \
        !           336: ({ struct obstack *__o1 = (OBSTACK);                                   \
        !           337:    void *value = (void *) __o1->object_base;                           \
        !           338:    if (__o1->next_free == value)                                       \
        !           339:      __o1->maybe_empty_object = 1;                                     \
        !           340:    __o1->next_free                                                     \
        !           341:      = __INT_TO_PTR ((__PTR_TO_INT (__o1->next_free)+__o1->alignment_mask)\
        !           342:                     & ~ (__o1->alignment_mask));                       \
        !           343:    ((__o1->next_free - (char *)__o1->chunk                             \
        !           344:      > __o1->chunk_limit - (char *)__o1->chunk)                                \
        !           345:     ? (__o1->next_free = __o1->chunk_limit) : 0);                      \
        !           346:    __o1->object_base = __o1->next_free;                                        \
        !           347:    value; })
        !           348: 
        !           349: #define obstack_free(OBSTACK, OBJ)                                     \
        !           350: __extension__                                                          \
        !           351: ({ struct obstack *__o = (OBSTACK);                                    \
        !           352:    void *__obj = (OBJ);                                                        \
        !           353:    if (__obj > (void *)__o->chunk && __obj < (void *)__o->chunk_limit)  \
        !           354:      __o->next_free = __o->object_base = __obj;                                \
        !           355:    else (obstack_free) (__o, __obj); })
        !           356: 
        !           357: #else /* not __GNUC__ or not __STDC__ */
        !           358: 
        !           359: #define obstack_object_size(h) \
        !           360:  (unsigned) ((h)->next_free - (h)->object_base)
        !           361: 
        !           362: #define obstack_room(h)                \
        !           363:  (unsigned) ((h)->chunk_limit - (h)->next_free)
        !           364: 
        !           365: #define obstack_grow(h,where,length)                                   \
        !           366: ( (h)->temp = (length),                                                        \
        !           367:   (((h)->next_free + (h)->temp > (h)->chunk_limit)                     \
        !           368:    ? (_obstack_newchunk ((h), (h)->temp), 0) : 0),                     \
        !           369:   bcopy (where, (h)->next_free, (h)->temp),                            \
        !           370:   (h)->next_free += (h)->temp)
        !           371: 
        !           372: #define obstack_grow0(h,where,length)                                  \
        !           373: ( (h)->temp = (length),                                                        \
        !           374:   (((h)->next_free + (h)->temp + 1 > (h)->chunk_limit)                 \
        !           375:    ? (_obstack_newchunk ((h), (h)->temp + 1), 0) : 0),                 \
        !           376:   bcopy (where, (h)->next_free, (h)->temp),                            \
        !           377:   (h)->next_free += (h)->temp,                                         \
        !           378:   *((h)->next_free)++ = 0)
        !           379: 
        !           380: #define obstack_1grow(h,datum)                                         \
        !           381: ( (((h)->next_free + 1 > (h)->chunk_limit)                             \
        !           382:    ? (_obstack_newchunk ((h), 1), 0) : 0),                             \
        !           383:   *((h)->next_free)++ = (datum))
        !           384: 
        !           385: #define obstack_ptr_grow(h,datum)                                      \
        !           386: ( (((h)->next_free + sizeof (char *) > (h)->chunk_limit)               \
        !           387:    ? (_obstack_newchunk ((h), sizeof (char *)), 0) : 0),               \
        !           388:   *((char **)(((h)->next_free+=sizeof(char *))-sizeof(char *))) = ((char *)datum))
        !           389: 
        !           390: #define obstack_int_grow(h,datum)                                      \
        !           391: ( (((h)->next_free + sizeof (int) > (h)->chunk_limit)                  \
        !           392:    ? (_obstack_newchunk ((h), sizeof (int)), 0) : 0),                  \
        !           393:   *((int *)(((h)->next_free+=sizeof(int))-sizeof(int))) = ((int)datum))
        !           394: 
        !           395: #define obstack_ptr_grow_fast(h,aptr) (*((char **)(h)->next_free)++ = (char *)aptr)
        !           396: #define obstack_int_grow_fast(h,aint) (*((int *)(h)->next_free)++ = (int)aint)
        !           397: 
        !           398: #define obstack_blank(h,length)                                                \
        !           399: ( (h)->temp = (length),                                                        \
        !           400:   (((h)->chunk_limit - (h)->next_free < (h)->temp)                     \
        !           401:    ? (_obstack_newchunk ((h), (h)->temp), 0) : 0),                     \
        !           402:   (h)->next_free += (h)->temp)
        !           403: 
        !           404: #define obstack_alloc(h,length)                                                \
        !           405:  (obstack_blank ((h), (length)), obstack_finish ((h)))
        !           406: 
        !           407: #define obstack_copy(h,where,length)                                   \
        !           408:  (obstack_grow ((h), (where), (length)), obstack_finish ((h)))
        !           409: 
        !           410: #define obstack_copy0(h,where,length)                                  \
        !           411:  (obstack_grow0 ((h), (where), (length)), obstack_finish ((h)))
        !           412: 
        !           413: #define obstack_finish(h)                                              \
        !           414: ( ((h)->next_free == (h)->object_base                                  \
        !           415:    ? (((h)->maybe_empty_object = 1), 0)                                        \
        !           416:    : 0),                                                               \
        !           417:   (h)->temp = __PTR_TO_INT ((h)->object_base),                         \
        !           418:   (h)->next_free                                                       \
        !           419:     = __INT_TO_PTR ((__PTR_TO_INT ((h)->next_free)+(h)->alignment_mask)        \
        !           420:                    & ~ ((h)->alignment_mask)),                         \
        !           421:   (((h)->next_free - (char *)(h)->chunk                                        \
        !           422:     > (h)->chunk_limit - (char *)(h)->chunk)                           \
        !           423:    ? ((h)->next_free = (h)->chunk_limit) : 0),                         \
        !           424:   (h)->object_base = (h)->next_free,                                   \
        !           425:   __INT_TO_PTR ((h)->temp))
        !           426: 
        !           427: #ifdef __STDC__
        !           428: #define obstack_free(h,obj)                                            \
        !           429: ( (h)->temp = (char *)(obj) - (char *) (h)->chunk,                     \
        !           430:   (((h)->temp > 0 && (h)->temp < (h)->chunk_limit - (char *) (h)->chunk)\
        !           431:    ? (int) ((h)->next_free = (h)->object_base                          \
        !           432:            = (h)->temp + (char *) (h)->chunk)                          \
        !           433:    : (((obstack_free) ((h), (h)->temp + (char *) (h)->chunk), 0), 0)))
        !           434: #else
        !           435: #define obstack_free(h,obj)                                            \
        !           436: ( (h)->temp = (char *)(obj) - (char *) (h)->chunk,                     \
        !           437:   (((h)->temp > 0 && (h)->temp < (h)->chunk_limit - (char *) (h)->chunk)\
        !           438:    ? (int) ((h)->next_free = (h)->object_base                          \
        !           439:            = (h)->temp + (char *) (h)->chunk)                          \
        !           440:    : (_obstack_free ((h), (h)->temp + (char *) (h)->chunk), 0)))
        !           441: #endif
        !           442: 
        !           443: #endif /* not __GNUC__ or not __STDC__ */
        !           444: 
        !           445: #endif /* not __OBSTACKS__ */

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