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/* Copyright (C) 2001-2006 Artifex Software, Inc.
All Rights Reserved.
This software is provided AS-IS with no warranty, either express or
implied.
This software is distributed under license and may not be copied, modified
or distributed except as expressly authorized under the terms of that
license. Refer to licensing information at http://www.artifex.com/
or contact Artifex Software, Inc., 7 Mt. Lassen Drive - Suite A-134,
San Rafael, CA 94903, U.S.A., +1(415)492-9861, for further information.
*/
/* $Id$ */
/* Client interface for "raw memory" allocator */
/* Initial version 02/03/1998 by John Desrosiers (soho@crl.com) */
/* Completely rewritten 6/26/1998 by L. Peter Deutsch <ghost@aladdin.com> */
#ifndef gsmemraw_INCLUDED
# define gsmemraw_INCLUDED
#if 0
/* gsmemraw was an abstract base class.
* it is no longer in use, instead use the concrete base class is gs_memory_t
* since gs_memory_t contains interfaces that must be availiable throughout the system
* is is unadvisable to have a class below it without these.
*/
/*
* This interface provides minimal memory allocation and freeing capability.
* It is meant to be used for "wholesale" allocation of blocks -- typically,
* but not only, via malloc -- which are then divided up into "retail"
* objects. However, since it is a subset (superclass) of the "retail"
* interface defined in gsmemory.h, retail allocators implement it as
* well, and in fact the malloc interface defined in gsmalloc.h is used for
* both wholesale and retail allocation.
*/
/*
* Define the structure for reporting memory manager statistics.
*/
typedef struct gs_memory_status_s {
/*
* "Allocated" space is the total amount of space acquired from
* the parent of the memory manager. It includes space used for
* allocated data, space available for allocation, and overhead.
*/
ulong allocated;
/*
* "Used" space is the amount of space used by allocated data
* plus overhead.
*/
ulong used;
/* used when wrapping if underlying allocator must be thread safe */
bool is_thread_safe;
} gs_memory_status_t;
/* Define the abstract type for the memory manager. */
#ifndef gs_raw_memory_t_DEFINED
#define gs_raw_memory_t_DEFINED
typedef struct gs_raw_memory_s gs_raw_memory_t;
#endif
/* Define the procedures for raw memory management. Memory managers have no
* standard constructor: each implementation defines its own, and is
* responsible for calling its superclass' initialization code first.
* Similarly, each implementation's destructor (release) must first take
* care of its own cleanup and then call the superclass' release.
*
* The allocation procedures must align objects as strictly as malloc.
* Formerly, the procedures were required to align objects as strictly
* as the compiler aligned structure members. However, the ANSI C standard
* does not require this -- it only requires malloc to align blocks
* strictly enough to prevent hardware access faults. Thus, for example,
* on the x86, malloc need not align blocks at all. And in fact, we have
* found one compiler (Microsoft VC 6) that 8-byte aligns 'double' members
* of structures, but whose malloc only 4-byte aligns its blocks.
* Ghostscript allocators could enforce the stricter alignment, but the
* few dozen lines of code required to implement this were rejected during
* code review as introducing too much risk for too little payoff. As a
* consequence of this,
*
* CLIENTS CANNOT ASSUME THAT BLOCKS RETURNED BY ANY OF THE ALLOCATION
* PROCEDURES ARE ALIGNED ANY MORE STRICTLY THAN IS REQUIRED BY THE
* HARDWARE.
*
* In particular, clients cannot assume that blocks returned by an allocator
* can be processed efficiently in any unit larger than a single byte: there
* is no guarantee that accessing any larger quantity will not require two
* memory accesses at the hardware level. Clients that want to process data
* efficiently in larger units must use ALIGNMENT_MOD to determine the
* actual alignment of the data in memory.
*/
/*
* Allocate bytes. The bytes are always aligned maximally
* if the processor requires alignment.
*
* Note that the object memory level can allocate bytes as
* either movable or immovable: raw memory blocks are
* always immovable.
*/
#define gs_memory_t_proc_alloc_bytes(proc, mem_t)\
byte *proc(mem_t *mem, uint nbytes, client_name_t cname)
#define gs_alloc_bytes_immovable(mem, nbytes, cname)\
((mem)->procs.alloc_bytes_immovable(mem, nbytes, cname))
/*
* Resize an object to a new number of elements. At the raw
* memory level, the "element" is a byte; for object memory
* (gsmemory.h), the object may be an an array of either
* bytes or structures. The new size may be larger than,
* the same as, or smaller than the old. If the new size is
* the same as the old, resize_object returns the same
* object; otherwise, it preserves the first min(old_size,
* new_size) bytes of the object's contents.
*/
#define gs_memory_t_proc_resize_object(proc, mem_t)\
void *proc(mem_t *mem, void *obj, uint new_num_elements,\
client_name_t cname)
#define gs_resize_object(mem, obj, newn, cname)\
((mem)->procs.resize_object(mem, obj, newn, cname))
/*
* Free an object (at the object memory level, this includes
* everything except strings). Note: data == 0 must be
* allowed, and must be a no-op.
*/
#define gs_memory_t_proc_free_object(proc, mem_t)\
void proc(mem_t *mem, void *data, client_name_t cname)
#define gs_free_object(mem, data, cname)\
((mem)->procs.free_object(mem, data, cname))
/*
* Report status (assigned, used).
*/
#define gs_memory_t_proc_status(proc, mem_t)\
void proc(mem_t *mem, gs_memory_status_t *status)
#define gs_memory_status(mem, pst)\
((mem)->procs.status(mem, pst))
/*
* Return the stable allocator for this allocator. The
* stable allocator allocates from the same heap and in
* the same VM space, but is not subject to save and restore.
* (It is the client's responsibility to avoid creating
* dangling pointers.)
*
* Note that the stable allocator may be the same allocator
* as this one.
*/
#define gs_memory_t_proc_stable(proc, mem_t)\
mem_t *proc(mem_t *mem)
#define gs_memory_stable(mem)\
((mem)->procs.stable(mem))
/*
* Free one or more of: data memory acquired by the allocator
* (FREE_ALL_DATA), overhead structures other than the
* allocator itself (FREE_ALL_STRUCTURES), and the allocator
* itself (FREE_ALL_ALLOCATOR). Note that this requires
* allocators to keep track of all the memory they have ever
* acquired, and where they acquired it. Note that this
* operation propagates to the stable allocator (if
* different).
*/
#define FREE_ALL_DATA 1
#define FREE_ALL_STRUCTURES 2
#define FREE_ALL_ALLOCATOR 4
#define FREE_ALL_EVERYTHING\
(FREE_ALL_DATA | FREE_ALL_STRUCTURES | FREE_ALL_ALLOCATOR)
#define gs_memory_t_proc_free_all(proc, mem_t)\
void proc(mem_t *mem, uint free_mask, client_name_t cname)
#define gs_memory_free_all(mem, free_mask, cname)\
((mem)->procs.free_all(mem, free_mask, cname))
/* Backward compatibility */
#define gs_free_all(mem)\
gs_memory_free_all(mem, FREE_ALL_DATA, "(free_all)")
/*
* Consolidate free space. This may be used as part of (or
* as an alternative to) garbage collection, or before
* giving up on an attempt to allocate.
*/
#define gs_memory_t_proc_consolidate_free(proc, mem_t)\
void proc(mem_t *mem)
#define gs_consolidate_free(mem)\
((mem)->procs.consolidate_free(mem))
/* Define the members of the procedure structure. */
#define gs_raw_memory_procs(mem_t)\
gs_memory_t_proc_alloc_bytes((*alloc_bytes_immovable), mem_t);\
gs_memory_t_proc_resize_object((*resize_object), mem_t);\
gs_memory_t_proc_free_object((*free_object), mem_t);\
gs_memory_t_proc_stable((*stable), mem_t);\
gs_memory_t_proc_status((*status), mem_t);\
gs_memory_t_proc_free_all((*free_all), mem_t);\
gs_memory_t_proc_consolidate_free((*consolidate_free), mem_t)
/*
* Define an abstract raw-memory allocator instance.
* Subclasses may have additional state.
*/
typedef struct gs_raw_memory_procs_s {
gs_raw_memory_procs(gs_raw_memory_t);
} gs_raw_memory_procs_t;
struct gs_raw_memory_s {
gs_raw_memory_t *stable_memory; /* cache the stable allocator */
gs_raw_memory_procs_t procs;
};
#endif /* 0 */
#endif /* gsmemraw_INCLUDED */
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