gecko-dev/lib/libpics/htmemory.h
1998-03-28 03:38:53 +00:00

181 lines
6.9 KiB
C

/* W3 Copyright statement
Copyright 1995 by: Massachusetts Institute of Technology (MIT), INRIA</H2>
This W3C software is being provided by the copyright holders under the
following license. By obtaining, using and/or copying this software,
you agree that you have read, understood, and will comply with the
following terms and conditions:
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee or royalty is hereby
granted, provided that the full text of this NOTICE appears on
<EM>ALL</EM> copies of the software and documentation or portions
thereof, including modifications, that you make.
<B>THIS SOFTWARE IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE NO
REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE,
BUT NOT LIMITATION, COPYRIGHT HOLDERS MAKE NO REPRESENTATIONS OR
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR
THAT THE USE OF THE SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY
THIRD PARTY PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS.
COPYRIGHT HOLDERS WILL BEAR NO LIABILITY FOR ANY USE OF THIS SOFTWARE
OR DOCUMENTATION.
The name and trademarks of copyright holders may NOT be used
in advertising or publicity pertaining to the software without
specific, written prior permission. Title to copyright in this
software and any associated documentation will at all times remain
with copyright holders.
*/
/* W3C Reference Library libwww Dynamic Memory Handlers
DYNAMIC MEMORY HANDLERS
*/
/*
** (c) COPYRIGHT MIT 1995.
** Please first read the full copyright statement in the file COPYRIGH.
*/
/*
This module defines any memory handler to be used by libwww for allocating and
de-allocating dynamic memory. As dynamic memory may be a scarce resource, it is
required that an application can handle memory exhaustion gracefully. This module
provides an interface that covers the following situations:
Handling of allocation, reallocation and de-allocation of dynamic memory
Recovering from temporary lack of available memory
Panic handling in case a new allocation fails
_Note_: The Library _core_ provides a default set of memory handlers for allocating and
de-allocating dynamic memory. In order to maintain a reasonable performance, they are
not registered dynamically but assigned using _C style macros_. Hence, it is not
possible to swap memory handler at run time but this was considered to be a reasonable
trade-off.
This module is implemented by HTMemory.c, and it is a part of the W3C Reference
Library.
*/
#ifndef HTMEMORY_H
#define HTMEMORY_H
/*
ALLOCATION, REALLOCATION AND DE-ALLOCATION
The Library provides a default set of methods for handling dynamic memory. They are
very basic and essentially identical to the C style malloc, calloc, realloc, and free:
*/
/* --- BEGIN added by mharmsen@netscape.com on 7/10/97 --- */
#ifndef BOOL
#define BOOL char
#endif
/* --- END added by mharmsen@netscape.com on 7/10/97 --- */
extern void* HTMemory_malloc(size_t size);
extern void* HTMemory_calloc(size_t count, size_t size);
extern void* HTMemory_realloc(void * ptr, size_t size);
extern void HTMemory_free(void* ptr);
/*
Memory Macros
The methods above are not referred directly in the Library. Instead we use a set of C
style macros. If you don't wany any memory management beyond normal malloc and alloc
then you can just use that instead of the HTMemory_* function. You can of course also
provide your own methods as well.
*/
#ifndef __FILE__
#define __FILE__ ""
#endif
#ifndef __LINE__
#define __LINE__ 0L
#endif
#define HT_MALLOC(size) HTMemory_malloc((size))
#define HT_CALLOC(count, size) HTMemory_calloc((count), (size))
#define HT_REALLOC(ptr, size) HTMemory_realloc((ptr), (size))
#define HT_FREE(pointer) {HTMemory_free((pointer));((pointer))=NULL;}
/*
MEMORY FREER FUNCTIONS
The dynamic memory freer functions are typically functions that are capable of freeing
large chunks of memory. In case a new allocation fails, the allocation method looks for
any registered freer functions to call. There can be multiple freer functions and after
each call, the allocation method tries again to allocate the desired amount of dynamic
memory. The freer functions are called in reverseorder meaning that the lastone
registered gets called first. That way, it is easy to add temporary freer functions
which then are guaranteed to be called first if a methods fails.
Add a Freer Function
You can add a freer function by using the following method. The Library may itself
register a set of free functions during initialization. If the application does not
register any freer functions then the Library looks how it can free internal memory.
The freer function is passed the total number of _bytes_ requested by the allocation.
*/
typedef void (*HTMemoryCallback()); /* jhines -- 7/9/97 */
/* typedef void HTMemoryCallback(size_t size); */
extern BOOL HTMemoryCall_add (HTMemoryCallback * cbf);
/*
Delete a Freer Function
Freer functions can be deleted at any time in which case they are not called anymore.
*/
extern BOOL HTMemoryCall_delete (HTMemoryCallback * cbf);
extern BOOL HTMemoryCall_deleteAll (void);
/*
PANIC HANDLING
If the freer functions are not capable of de-allocation enough memory then the
application must have an organized way of closing down. This is done using the panic
handler. In the libwww, each allocation is tested and HT_OUTOFMEMis called if a NULLwas
returned. HT_OUTOFMEMis a macro which by default calls HTMemory_outofmem()but of course
can point to any method. The default handler calls an exit function defined by the
application in a call to HTMemory_setExit(). If the application has _not_ defined an
exit function, HTMemory_outofmem()prints an error message and calls exit(1).
*/
typedef void HTMemory_exitCallback(char *name, char *file, unsigned long line);
extern void HTMemory_setExit(HTMemory_exitCallback * pExit);
extern HTMemory_exitCallback * HTMemory_exit(void);
/*
Call the Exit Handler
If an allocation fails then this function is called. If the application has registered
its own panic handler then this is called directly from this function. Otherwise, the
default behavior is to write a small message to stderr and then exit.
*/
#define outofmem(file, name) HT_OUTOFMEM(name)
#define HT_OUTOFMEM(name) HTMemory_outofmem((name), __FILE__, __LINE__)
extern void HTMemory_outofmem(char * name, char * file, unsigned long line);
/*
*/
#endif /* HTMEMORY_H */
/*
___________________________________
@(#) $Id: htmemory.h,v 3.1 1998/03/28 03:32:07 ltabb Exp $
*/