| /* objalloc.h -- routines to allocate memory for objects |
| Copyright 1997-2012 Free Software Foundation, Inc. |
| Written by Ian Lance Taylor, Cygnus Solutions. |
| |
| 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, 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, 51 Franklin Street - Fifth Floor, |
| Boston, MA 02110-1301, USA. */ |
| |
| #ifndef OBJALLOC_H |
| #define OBJALLOC_H |
| |
| #include "ansidecl.h" |
| |
| /* These routines allocate space for an object. The assumption is |
| that the object will want to allocate space as it goes along, but |
| will never want to free any particular block. There is a function |
| to free a block, which also frees all more recently allocated |
| blocks. There is also a function to free all the allocated space. |
| |
| This is essentially a specialization of obstacks. The main |
| difference is that a block may not be allocated a bit at a time. |
| Another difference is that these routines are always built on top |
| of malloc, and always pass an malloc failure back to the caller, |
| unlike more recent versions of obstacks. */ |
| |
| /* This is what an objalloc structure looks like. Callers should not |
| refer to these fields, nor should they allocate these structure |
| themselves. Instead, they should only create them via |
| objalloc_init, and only access them via the functions and macros |
| listed below. The structure is only defined here so that we can |
| access it via macros. */ |
| |
| struct objalloc |
| { |
| char *current_ptr; |
| unsigned int current_space; |
| void *chunks; |
| }; |
| |
| /* Work out the required alignment. */ |
| |
| struct objalloc_align { char x; double d; }; |
| |
| #if defined (__STDC__) && __STDC__ |
| #ifndef offsetof |
| #include <stddef.h> |
| #endif |
| #endif |
| #ifndef offsetof |
| #define offsetof(TYPE, MEMBER) ((unsigned long) &((TYPE *)0)->MEMBER) |
| #endif |
| #define OBJALLOC_ALIGN offsetof (struct objalloc_align, d) |
| |
| /* Create an objalloc structure. Returns NULL if malloc fails. */ |
| |
| extern struct objalloc *objalloc_create (void); |
| |
| /* Allocate space from an objalloc structure. Returns NULL if malloc |
| fails. */ |
| |
| extern void *_objalloc_alloc (struct objalloc *, unsigned long); |
| |
| /* The macro version of objalloc_alloc. We only define this if using |
| gcc, because otherwise we would have to evaluate the arguments |
| multiple times, or use a temporary field as obstack.h does. */ |
| |
| #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 |
| |
| #define objalloc_alloc(o, l) \ |
| __extension__ \ |
| ({ struct objalloc *__o = (o); \ |
| unsigned long __len = (l); \ |
| if (__len == 0) \ |
| __len = 1; \ |
| __len = (__len + OBJALLOC_ALIGN - 1) &~ (OBJALLOC_ALIGN - 1); \ |
| (__len != 0 && __len <= __o->current_space \ |
| ? (__o->current_ptr += __len, \ |
| __o->current_space -= __len, \ |
| (void *) (__o->current_ptr - __len)) \ |
| : _objalloc_alloc (__o, __len)); }) |
| |
| #else /* ! __GNUC__ */ |
| |
| #define objalloc_alloc(o, l) _objalloc_alloc ((o), (l)) |
| |
| #endif /* ! __GNUC__ */ |
| |
| /* Free an entire objalloc structure. */ |
| |
| extern void objalloc_free (struct objalloc *); |
| |
| /* Free a block allocated by objalloc_alloc. This also frees all more |
| recently allocated blocks. */ |
| |
| extern void objalloc_free_block (struct objalloc *, void *); |
| |
| #endif /* OBJALLOC_H */ |