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Diffstat (limited to 'malloc/obstack.h')
| -rw-r--r-- | malloc/obstack.h | 575 |
1 files changed, 575 insertions, 0 deletions
diff --git a/malloc/obstack.h b/malloc/obstack.h new file mode 100644 index 0000000000..152fbbc655 --- /dev/null +++ b/malloc/obstack.h @@ -0,0 +1,575 @@ +/* obstack.h - object stack macros + Copyright (C) 1988,89,90,91,92,93,94,96 Free Software Foundation, Inc. + + This file is part of the GNU C Library. Its master source is NOT part of + the C library, however. The master source lives in /gd/gnu/lib. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +/* 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 "fascist 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 symbol 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 beginning of the new larger chunk. We then carry on +accreting characters to the end of the object as we normally 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' an 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 __OBSTACK_H__ +#define __OBSTACK_H__ + +/* 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 + +/* We need the type of the resulting object. In ANSI C it is ptrdiff_t + but in traditional C it is usually long. If we are in ANSI C and + don't already have ptrdiff_t get it. */ + +#if defined (__STDC__) && __STDC__ && ! defined (offsetof) +#if defined (__GNUC__) && defined (IN_GCC) +/* On Next machine, the system's stddef.h screws up if included + after we have defined just ptrdiff_t, so include all of stddef.h. + Otherwise, define just ptrdiff_t, which is all we need. */ +#ifndef __NeXT__ +#define __need_ptrdiff_t +#endif +#endif + +#include <stddef.h> +#endif + +#if defined (__STDC__) && __STDC__ +#define PTR_INT_TYPE ptrdiff_t +#else +#define PTR_INT_TYPE long +#endif + +#if defined (_LIBC) || defined (HAVE_STRING_H) +#include <string.h> +#else +#ifndef memcpy +#define memcpy(To, From, N) bcopy (From, To, N) +#endif +#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 */ + PTR_INT_TYPE temp; /* Temporary for some macros. */ + int alignment_mask; /* Mask of alignment for each object. */ +#if defined (__STDC__) && __STDC__ + /* These prototypes vary based on `use_extra_arg', and we use + casts to the prototypeless function type in all assignments, + but having prototypes here quiets -Wstrict-prototypes. */ + struct _obstack_chunk *(*chunkfun) (void *, long); + void (*freefun) (void *, struct _obstack_chunk *); + void *extra_arg; /* first arg for chunk alloc/dealloc funcs */ +#else + struct _obstack_chunk *(*chunkfun) (); /* User's fcn to allocate a chunk. */ + void (*freefun) (); /* User's function to free a chunk. */ + char *extra_arg; /* first arg for chunk alloc/dealloc funcs */ +#endif + unsigned use_extra_arg:1; /* chunk alloc/dealloc funcs take extra arg */ + unsigned maybe_empty_object:1;/* There is a possibility that the current + chunk contains a zero-length object. This + prevents freeing the chunk if we allocate + a bigger chunk to replace it. */ +}; + +/* Declare the external functions we use; they are in obstack.c. */ + +#if defined (__STDC__) && __STDC__ +extern void _obstack_newchunk (struct obstack *, int); +extern void _obstack_free (struct obstack *, void *); +extern int _obstack_begin (struct obstack *, int, int, + void *(*) (long), void (*) (void *)); +extern int _obstack_begin_1 (struct obstack *, int, int, + void *(*) (void *, long), + void (*) (void *, void *), void *); +extern int _obstack_memory_used (struct obstack *); +#else +extern void _obstack_newchunk (); +extern void _obstack_free (); +extern int _obstack_begin (); +extern int _obstack_begin_1 (); +extern int _obstack_memory_used (); +#endif + +#if defined (__STDC__) && __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_ptr_grow (struct obstack *obstack, void *data); +void obstack_int_grow (struct obstack *obstack, int data); + +void * obstack_finish (struct obstack *obstack); + +int obstack_object_size (struct obstack *obstack); + +int obstack_room (struct obstack *obstack); +void obstack_make_room (struct obstack *obstack, int size); +void obstack_1grow_fast (struct obstack *obstack, int data_char); +void obstack_ptr_grow_fast (struct obstack *obstack, void *data); +void obstack_int_grow_fast (struct obstack *obstack, int data); +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); +int obstack_memory_used (struct obstack *obstack); + +#endif /* __STDC__ */ + +/* Non-ANSI C cannot really support alternative functions for these macros, + so we do not declare them. */ + +/* Error handler called when `obstack_chunk_alloc' failed to allocate + more memory. This can be set to a user defined function. The + default action is to print a message and abort. */ +#if defined (__STDC__) && __STDC__ +extern void (*obstack_alloc_failed_handler) (void); +#else +extern void (*obstack_alloc_failed_handler) (); +#endif + +/* Exit value used when `print_and_abort' is used. */ +extern int obstack_exit_failure; + +/* 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) + +/* To prevent prototype warnings provide complete argument list in + standard C version. */ +#if defined (__STDC__) && __STDC__ + +#define obstack_init(h) \ + _obstack_begin ((h), 0, 0, \ + (void *(*) (long)) obstack_chunk_alloc, (void (*) (void *)) obstack_chunk_free) + +#define obstack_begin(h, size) \ + _obstack_begin ((h), (size), 0, \ + (void *(*) (long)) obstack_chunk_alloc, (void (*) (void *)) obstack_chunk_free) + +#define obstack_specify_allocation(h, size, alignment, chunkfun, freefun) \ + _obstack_begin ((h), (size), (alignment), \ + (void *(*) (long)) (chunkfun), (void (*) (void *)) (freefun)) + +#define obstack_specify_allocation_with_arg(h, size, alignment, chunkfun, freefun, arg) \ + _obstack_begin_1 ((h), (size), (alignment), \ + (void *(*) (long)) (chunkfun), (void (*) (void *)) (freefun), (arg)) + +#define obstack_chunkfun(h, newchunkfun) \ + ((h) -> chunkfun = (struct _obstack_chunk *(*)(long)) (newchunkfun)) + +#define obstack_freefun(h, newfreefun) \ + ((h) -> freefun = (void (*)(void *)) (newfreefun)) + +#else + +#define obstack_init(h) \ + _obstack_begin ((h), 0, 0, \ + (void *(*) ()) obstack_chunk_alloc, (void (*) ()) obstack_chunk_free) + +#define obstack_begin(h, size) \ + _obstack_begin ((h), (size), 0, \ + (void *(*) ()) obstack_chunk_alloc, (void (*) ()) obstack_chunk_free) + +#define obstack_specify_allocation(h, size, alignment, chunkfun, freefun) \ + _obstack_begin ((h), (size), (alignment), \ + (void *(*) ()) (chunkfun), (void (*) ()) (freefun)) + +#define obstack_specify_allocation_with_arg(h, size, alignment, chunkfun, freefun, arg) \ + _obstack_begin_1 ((h), (size), (alignment), \ + (void *(*) ()) (chunkfun), (void (*) ()) (freefun), (arg)) + +#define obstack_chunkfun(h, newchunkfun) \ + ((h) -> chunkfun = (struct _obstack_chunk *(*)()) (newchunkfun)) + +#define obstack_freefun(h, newfreefun) \ + ((h) -> freefun = (void (*)()) (newfreefun)) + +#endif + +#define obstack_1grow_fast(h,achar) (*((h)->next_free)++ = achar) + +#define obstack_blank_fast(h,n) ((h)->next_free += (n)) + +#define obstack_memory_used(h) _obstack_memory_used (h) + +#if defined (__GNUC__) && defined (__STDC__) && __STDC__ +/* NextStep 2.0 cc is really gcc 1.93 but it defines __GNUC__ = 2 and + does not implement __extension__. But that compiler doesn't define + __GNUC_MINOR__. */ +#if __GNUC__ < 2 || (__NeXT__ && !__GNUC_MINOR__) +#define __extension__ +#endif + +/* 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) \ + __extension__ \ + ({ struct obstack *__o = (OBSTACK); \ + (unsigned) (__o->next_free - __o->object_base); }) + +#define obstack_room(OBSTACK) \ + __extension__ \ + ({ struct obstack *__o = (OBSTACK); \ + (unsigned) (__o->chunk_limit - __o->next_free); }) + +#define obstack_make_room(OBSTACK,length) \ +__extension__ \ +({ struct obstack *__o = (OBSTACK); \ + int __len = (length); \ + if (__o->chunk_limit - __o->next_free < __len) \ + _obstack_newchunk (__o, __len); \ + (void) 0; }) + +#define obstack_grow(OBSTACK,where,length) \ +__extension__ \ +({ struct obstack *__o = (OBSTACK); \ + int __len = (length); \ + if (__o->next_free + __len > __o->chunk_limit) \ + _obstack_newchunk (__o, __len); \ + memcpy (__o->next_free, (char *) (where), __len); \ + __o->next_free += __len; \ + (void) 0; }) + +#define obstack_grow0(OBSTACK,where,length) \ +__extension__ \ +({ struct obstack *__o = (OBSTACK); \ + int __len = (length); \ + if (__o->next_free + __len + 1 > __o->chunk_limit) \ + _obstack_newchunk (__o, __len + 1); \ + memcpy (__o->next_free, (char *) (where), __len); \ + __o->next_free += __len; \ + *(__o->next_free)++ = 0; \ + (void) 0; }) + +#define obstack_1grow(OBSTACK,datum) \ +__extension__ \ +({ struct obstack *__o = (OBSTACK); \ + if (__o->next_free + 1 > __o->chunk_limit) \ + _obstack_newchunk (__o, 1); \ + *(__o->next_free)++ = (datum); \ + (void) 0; }) + +/* These assume that the obstack alignment is good enough for pointers or ints, + and that the data added so far to the current object + shares that much alignment. */ + +#define obstack_ptr_grow(OBSTACK,datum) \ +__extension__ \ +({ struct obstack *__o = (OBSTACK); \ + if (__o->next_free + sizeof (void *) > __o->chunk_limit) \ + _obstack_newchunk (__o, sizeof (void *)); \ + *((void **)__o->next_free)++ = ((void *)datum); \ + (void) 0; }) + +#define obstack_int_grow(OBSTACK,datum) \ +__extension__ \ +({ struct obstack *__o = (OBSTACK); \ + if (__o->next_free + sizeof (int) > __o->chunk_limit) \ + _obstack_newchunk (__o, sizeof (int)); \ + *((int *)__o->next_free)++ = ((int)datum); \ + (void) 0; }) + +#define obstack_ptr_grow_fast(h,aptr) (*((void **) (h)->next_free)++ = (void *)aptr) +#define obstack_int_grow_fast(h,aint) (*((int *) (h)->next_free)++ = (int) aint) + +#define obstack_blank(OBSTACK,length) \ +__extension__ \ +({ struct obstack *__o = (OBSTACK); \ + int __len = (length); \ + if (__o->chunk_limit - __o->next_free < __len) \ + _obstack_newchunk (__o, __len); \ + __o->next_free += __len; \ + (void) 0; }) + +#define obstack_alloc(OBSTACK,length) \ +__extension__ \ +({ struct obstack *__h = (OBSTACK); \ + obstack_blank (__h, (length)); \ + obstack_finish (__h); }) + +#define obstack_copy(OBSTACK,where,length) \ +__extension__ \ +({ struct obstack *__h = (OBSTACK); \ + obstack_grow (__h, (where), (length)); \ + obstack_finish (__h); }) + +#define obstack_copy0(OBSTACK,where,length) \ +__extension__ \ +({ struct obstack *__h = (OBSTACK); \ + obstack_grow0 (__h, (where), (length)); \ + obstack_finish (__h); }) + +/* The local variable is named __o1 to avoid a name conflict + when obstack_blank is called. */ +#define obstack_finish(OBSTACK) \ +__extension__ \ +({ struct obstack *__o1 = (OBSTACK); \ + void *value; \ + value = (void *) __o1->object_base; \ + if (__o1->next_free == value) \ + __o1->maybe_empty_object = 1; \ + __o1->next_free \ + = __INT_TO_PTR ((__PTR_TO_INT (__o1->next_free)+__o1->alignment_mask)\ + & ~ (__o1->alignment_mask)); \ + if (__o1->next_free - (char *)__o1->chunk \ + > __o1->chunk_limit - (char *)__o1->chunk) \ + __o1->next_free = __o1->chunk_limit; \ + __o1->object_base = __o1->next_free; \ + value; }) + +#define obstack_free(OBSTACK, OBJ) \ +__extension__ \ +({ 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__ */ + +#define obstack_object_size(h) \ + (unsigned) ((h)->next_free - (h)->object_base) + +#define obstack_room(h) \ + (unsigned) ((h)->chunk_limit - (h)->next_free) + +/* Note that the call to _obstack_newchunk is enclosed in (..., 0) + so that we can avoid having void expressions + in the arms of the conditional expression. + Casting the third operand to void was tried before, + but some compilers won't accept it. */ + +#define obstack_make_room(h,length) \ +( (h)->temp = (length), \ + (((h)->next_free + (h)->temp > (h)->chunk_limit) \ + ? (_obstack_newchunk ((h), (h)->temp), 0) : 0)) + +#define obstack_grow(h,where,length) \ +( (h)->temp = (length), \ + (((h)->next_free + (h)->temp > (h)->chunk_limit) \ + ? (_obstack_newchunk ((h), (h)->temp), 0) : 0), \ + memcpy ((h)->next_free, (char *) (where), (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) : 0), \ + memcpy ((h)->next_free, (char *) (where), (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) : 0), \ + (*((h)->next_free)++ = (datum))) + +#define obstack_ptr_grow(h,datum) \ +( (((h)->next_free + sizeof (char *) > (h)->chunk_limit) \ + ? (_obstack_newchunk ((h), sizeof (char *)), 0) : 0), \ + (*((char **) (((h)->next_free+=sizeof(char *))-sizeof(char *))) = ((char *) datum))) + +#define obstack_int_grow(h,datum) \ +( (((h)->next_free + sizeof (int) > (h)->chunk_limit) \ + ? (_obstack_newchunk ((h), sizeof (int)), 0) : 0), \ + (*((int *) (((h)->next_free+=sizeof(int))-sizeof(int))) = ((int) datum))) + +#define obstack_ptr_grow_fast(h,aptr) (*((char **) (h)->next_free)++ = (char *) aptr) +#define obstack_int_grow_fast(h,aint) (*((int *) (h)->next_free)++ = (int) aint) + +#define obstack_blank(h,length) \ +( (h)->temp = (length), \ + (((h)->chunk_limit - (h)->next_free < (h)->temp) \ + ? (_obstack_newchunk ((h), (h)->temp), 0) : 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)->next_free == (h)->object_base \ + ? (((h)->maybe_empty_object = 1), 0) \ + : 0), \ + (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)) + +#if defined (__STDC__) && __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), 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) \ + : (_obstack_free ((h), (h)->temp + (char *) (h)->chunk), 0))) +#endif + +#endif /* not __GNUC__ or not __STDC__ */ + +#endif /* not __OBSTACK_H__ */ |