mirror of
git://git.sv.gnu.org/emacs.git
synced 2025-12-19 20:30:29 -08:00
c0bb4cd3cd
This change will be integrated but ignored (-ay) to the gg-epcore/union sources, so that they retain HopeNames. Copied from Perforce Change: 24911 ServerID: perforce.ravenbrook.com
125 lines
3.1 KiB
C
125 lines
3.1 KiB
C
/* impl.c.boot: BOOTSTRAP ALLOCATOR
|
|
*
|
|
* $Id$
|
|
* Copyright (c) 2001 Ravenbrook Limited.
|
|
*
|
|
* .overview: A structure and protocols for allocating memory from a
|
|
* given block. Very simple, it basically just increments a pointer.
|
|
*
|
|
* .boot.c: The Bootstrap Allocator is used to allocate C structures
|
|
* for use in the implementation, not client objects. Therefore,
|
|
* we use "C types" (void *, size_t) not "client types" (Addr, Size).
|
|
*/
|
|
|
|
#include "boot.h"
|
|
#include "mpm.h"
|
|
|
|
SRCID(boot, "$Id$");
|
|
|
|
|
|
#define BootBlockSig ((Sig)0x519B002B) /* SIGnature BOOT Block */
|
|
|
|
|
|
/* BootBlockCheck -- check a BootBlock structure */
|
|
|
|
Bool BootBlockCheck(BootBlock boot)
|
|
{
|
|
CHECKS(BootBlock, boot);
|
|
CHECKL(boot->base != NULL);
|
|
CHECKL(boot->alloc != NULL);
|
|
CHECKL(boot->limit != NULL);
|
|
CHECKL(boot->base <= boot->alloc);
|
|
CHECKL(boot->alloc <= boot->limit);
|
|
CHECKL(boot->alloc < boot->limit);
|
|
|
|
return TRUE;
|
|
}
|
|
|
|
|
|
/* BootBlockInit -- initialize a BootBlock
|
|
*
|
|
* boot: a pointer to the structure to be initialized
|
|
* (must have been allocated by the caller, probably on the stack).
|
|
* base: a pointer to the base of the memory to be allocated from
|
|
* from (the memory need not be committed)
|
|
* limit: a pointer to the limit of the memory to be allocated from
|
|
*/
|
|
|
|
Res BootBlockInit(BootBlockStruct *boot, void *base, void *limit)
|
|
{
|
|
/* Can't check boot as we are supposed to be initializing it */
|
|
AVER(boot != NULL);
|
|
AVER(base != NULL);
|
|
AVER(limit != NULL);
|
|
AVER(base < limit);
|
|
|
|
boot->base = base;
|
|
boot->alloc = base;
|
|
boot->limit = limit;
|
|
boot->sig = BootBlockSig;
|
|
|
|
AVERT(BootBlock, boot);
|
|
return ResOK;
|
|
}
|
|
|
|
|
|
/* BootBlockFinish -- finish a BootBlock structure */
|
|
|
|
void BootBlockFinish(BootBlock boot)
|
|
{
|
|
AVERT(BootBlock, boot);
|
|
|
|
boot->base = boot->alloc = boot->limit = NULL;
|
|
boot->sig = SigInvalid;
|
|
}
|
|
|
|
|
|
/* BootAllocated
|
|
*
|
|
* Returns the total amount allocated using this descriptor
|
|
*/
|
|
size_t BootAllocated(BootBlock boot)
|
|
{
|
|
AVERT(BootBlock, boot);
|
|
|
|
return PointerOffset(boot->base, boot->alloc);
|
|
}
|
|
|
|
|
|
/* BootAlloc -- allocate from BootBlock structure
|
|
*
|
|
* preturn: The returned pointer, see .boot.c.
|
|
* boot: must have been initialized with BootBlockInit().
|
|
* size: size of requested object, see .boot.c.
|
|
* align: required alignment of object, see .boot.c.
|
|
*/
|
|
|
|
Res BootAlloc(void **pReturn, BootBlock boot, size_t size, size_t align)
|
|
{
|
|
void *blockBase, *blockLimit; /* base, limit of candidate block */
|
|
|
|
AVER(pReturn != NULL);
|
|
AVERT(BootBlock, boot);
|
|
AVER(size > 0);
|
|
AVER(AlignCheck((Align)align));
|
|
|
|
/* Align alloc pointer up and bounds check. */
|
|
blockBase = PointerAlignUp(boot->alloc, align);
|
|
if(boot->limit <= blockBase || blockBase < boot->alloc) {
|
|
return ResMEMORY;
|
|
}
|
|
blockLimit = PointerAdd(blockBase, size);
|
|
/* Following checks that the ordering constraint holds: */
|
|
/* boot->alloc <= blockBase < blockLimit <= boot->limit */
|
|
/* (if it doesn't hold then something overallocated/wrapped round) */
|
|
if(blockBase < boot->alloc ||
|
|
blockLimit <= blockBase ||
|
|
boot->limit < blockLimit) {
|
|
return ResMEMORY;
|
|
}
|
|
|
|
/* Fits! So allocate it */
|
|
boot->alloc = blockLimit;
|
|
*pReturn = blockBase;
|
|
return ResOK;
|
|
}
|