[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Changes to obstack.h [branch-1_4]
|
From: |
Eric Blake |
|
Subject: |
Changes to obstack.h [branch-1_4] |
|
Date: |
Thu, 15 Jun 2006 13:13:29 +0000 |
CVSROOT: /sources/m4
Module name: m4
Branch: branch-1_4
Changes by: Eric Blake <ericb> 06/06/15 13:13:26
Index: obstack.h
===================================================================
RCS file: obstack.h
diff -N obstack.h
--- obstack.h 1 May 2005 11:54:12 -0000 1.1.1.1.2.1
+++ /dev/null 1 Jan 1970 00:00:00 -0000
@@ -1,520 +0,0 @@
-/* obstack.h - object stack macros
-
- Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1994
- 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 2 of the License, 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, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- 02110-1301 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
-
-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. */
- 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 */
- 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. */
- unsigned alloc_failed:1; /* chunk alloc func returned 0 */
-};
-
-/* 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 *(*) (), void (*) ());
-extern int _obstack_begin_1 (struct obstack *, int, int,
- void *(*) (), void (*) (), void *);
-#else
-extern void _obstack_newchunk ();
-extern void _obstack_free ();
-extern int _obstack_begin ();
-extern int _obstack_begin_1 ();
-#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_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);
-
-#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)->alloc_failed ? 0 : (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)->alloc_failed ? 0 : (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, \
- (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))
-
-#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__)
-/* 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); \
- __o->alloc_failed ? 0 : \
- (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_grow(OBSTACK,where,length) \
-__extension__ \
-({ struct obstack *__o = (OBSTACK); \
- int __len = (length); \
- if (__o->next_free + __len > __o->chunk_limit) \
- _obstack_newchunk (__o, __len); \
- if (!__o->alloc_failed) \
- { \
- bcopy ((char *) (where), __o->next_free, __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); \
- if (!__o->alloc_failed) \
- { \
- bcopy ((char *) (where), __o->next_free, __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); \
- if (!__o->alloc_failed) \
- *(__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 *)); \
- if (!__o->alloc_failed) \
- *((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)); \
- if (!__o->alloc_failed) \
- *((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); \
- if (!__o->alloc_failed) \
- __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;
\
- if (__o1->alloc_failed) \
- value = 0;
\
- else
\
- { \
- 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)->alloc_failed ? 0 : (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_grow(h,where,length) \
-( (h)->temp = (length),
\
- (((h)->next_free + (h)->temp > (h)->chunk_limit) \
- ? (_obstack_newchunk ((h), (h)->temp), 0) : 0), \
- ((h)->alloc_failed ? 0 : \
- (bcopy ((char *) (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) : 0), \
- ((h)->alloc_failed ? 0 : \
- (bcopy ((char *) (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) : 0), \
- ((h)->alloc_failed ? 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), \
- ((h)->alloc_failed ? 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), \
- ((h)->alloc_failed ? 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)->alloc_failed ? 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)->alloc_failed ? 0 : \
- (((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__ */
| [Prev in Thread] |
Current Thread |
[Next in Thread] |
- Changes to obstack.h [branch-1_4],
Eric Blake <=