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/* objalloc.h -- routines to allocate memory for objects |
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Copyright (C) 1997-2021 Free Software Foundation, Inc. |
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Written by Ian Lance Taylor, Cygnus Solutions. |
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|
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This program is free software; you can redistribute it and/or modify it |
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under the terms of the GNU General Public License as published by the |
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Free Software Foundation; either version 2, or (at your option) any |
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later version. |
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|
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with this program; if not, write to the Free Software |
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Foundation, 51 Franklin Street - Fifth Floor, |
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Boston, MA 02110-1301, USA. */ |
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|
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#ifndef OBJALLOC_H |
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#define OBJALLOC_H |
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|
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#include "ansidecl.h" |
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|
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/* These routines allocate space for an object. The assumption is |
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that the object will want to allocate space as it goes along, but |
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will never want to free any particular block. There is a function |
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to free a block, which also frees all more recently allocated |
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blocks. There is also a function to free all the allocated space. |
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|
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This is essentially a specialization of obstacks. The main |
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difference is that a block may not be allocated a bit at a time. |
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Another difference is that these routines are always built on top |
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of malloc, and always pass an malloc failure back to the caller, |
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unlike more recent versions of obstacks. */ |
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|
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/* This is what an objalloc structure looks like. Callers should not |
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refer to these fields, nor should they allocate these structure |
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themselves. Instead, they should only create them via |
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objalloc_init, and only access them via the functions and macros |
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listed below. The structure is only defined here so that we can |
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access it via macros. */ |
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|
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struct objalloc |
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{ |
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char *current_ptr; |
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unsigned int current_space; |
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void *chunks; |
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}; |
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|
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/* Work out the required alignment. */ |
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|
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struct objalloc_align { char x; double d; }; |
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#if defined (__STDC__) && __STDC__ |
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#ifndef offsetof |
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#include <stddef.h> |
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#endif |
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#endif |
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#ifndef offsetof |
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#define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER) |
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#endif |
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#define OBJALLOC_ALIGN offsetof (struct objalloc_align, d) |
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|
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/* Create an objalloc structure. Returns NULL if malloc fails. */ |
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|
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extern struct objalloc *objalloc_create (void); |
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|
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/* Allocate space from an objalloc structure. Returns NULL if malloc |
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fails. */ |
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|
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extern void *_objalloc_alloc (struct objalloc *, unsigned long); |
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|
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/* The macro version of objalloc_alloc. We only define this if using |
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gcc, because otherwise we would have to evaluate the arguments |
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multiple times, or use a temporary field as obstack.h does. */ |
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|
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#if defined (__GNUC__) && defined (__STDC__) && __STDC__ |
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|
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/* NextStep 2.0 cc is really gcc 1.93 but it defines __GNUC__ = 2 and |
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does not implement __extension__. But that compiler doesn't define |
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__GNUC_MINOR__. */ |
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#if __GNUC__ < 2 || (__NeXT__ && !__GNUC_MINOR__) |
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#define __extension__ |
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#endif |
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|
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#define objalloc_alloc(o, l) \ |
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__extension__ \ |
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({ struct objalloc *__o = (o); \ |
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unsigned long __len = (l); \ |
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if (__len == 0) \ |
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__len = 1; \ |
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__len = (__len + OBJALLOC_ALIGN - 1) &~ (OBJALLOC_ALIGN - 1); \ |
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(__len != 0 && __len <= __o->current_space \ |
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? (__o->current_ptr += __len, \ |
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__o->current_space -= __len, \ |
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(void *) (__o->current_ptr - __len)) \ |
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: _objalloc_alloc (__o, __len)); }) |
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|
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#else /* ! __GNUC__ */ |
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|
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#define objalloc_alloc(o, l) _objalloc_alloc ((o), (l)) |
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#endif /* ! __GNUC__ */ |
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|
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/* Free an entire objalloc structure. */ |
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extern void objalloc_free (struct objalloc *); |
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/* Free a block allocated by objalloc_alloc. This also frees all more |
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recently allocated blocks. */ |
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|
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extern void objalloc_free_block (struct objalloc *, void *); |
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|
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#endif /* OBJALLOC_H */ |
