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Diffstat (limited to 'gnu/usr.bin/gdb/obstack.h')
| -rw-r--r-- | gnu/usr.bin/gdb/obstack.h | 372 |
1 files changed, 372 insertions, 0 deletions
diff --git a/gnu/usr.bin/gdb/obstack.h b/gnu/usr.bin/gdb/obstack.h new file mode 100644 index 000000000000..27c017e2f253 --- /dev/null +++ b/gnu/usr.bin/gdb/obstack.h @@ -0,0 +1,372 @@ +/* obstack.h - object stack macros + Copyright (C) 1988 Free Software Foundation, Inc. + +This program is free software; you can redistribute it and/or modify it +under the terms of the GNU General Public License as published by the +Free Software Foundation; either version 1, or (at your option) any +later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with this program; if not, write to the Free Software +Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + + +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__ + +/* We use subtraction of (char *)0 instead of casting to int + because on word-addressable machines a simple cast to int + may ignore the byte-within-word field of the pointer. */ + +#ifndef __PTR_TO_INT +#define __PTR_TO_INT(P) ((P) - (char *)0) +#endif + +#ifndef __INT_TO_PTR +#define __INT_TO_PTR(P) ((P) + (char *)0) +#endif + +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. */ +}; + +#ifdef __STDC__ + +/* Do the function-declarations after the structs + but 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 * obstack_base (struct obstack *obstack); +void * obstack_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. */ + +/* 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), 0, 0, obstack_chunk_alloc, obstack_chunk_free) + +#define obstack_begin(h, size) \ + _obstack_begin ((h), (size), 0, 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 (__GNUC__) && defined (__STDC__) + +/* For GNU C, if not -traditional, + 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. */ + +#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 \ + = __INT_TO_PTR ((__PTR_TO_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 __GNUC__ or not __STDC__ */ + +/* 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 = __PTR_TO_INT ((h)->object_base), \ + (h)->next_free \ + = __INT_TO_PTR ((__PTR_TO_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, \ + __INT_TO_PTR ((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) \ + : ((obstack_free) ((h), (h)->temp + (char *) (h)->chunk), 0))) +#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 __GNUC__ or not __STDC__ */ + +#endif /* not __OBSTACKS__ */ + |