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/************************************************************/
/* Windows Write, Copyright 1985-1992 Microsoft Corporation */
/************************************************************/
/*
heapDefs.h - include file for the storage allocator.
*/
#if 0
Storage allocation
NULL
|
| pHeapFirst
| ________________
| |_____cw________| hh
| | block | *Fgr <----------------------\
| | of | |
| | words | |
| |_______________| |
phhFree---->______cw______| hh |
|--|------phhNext____| |
| |____phhPrev--------------| |
| | | | |
| | | | |
| | | | |
| | block | | |
| | of | | |
| | words | | |
| |_______________| | |
| |_____cw________| | |
| | . | *Fgr<---|-------------------|-\
| |---------------| | | |
| |_____cw________|<--------/ | |
|-----phhNext_____| | |
| phhPrev---------| | |
| | | | |
| | NULL | |
|_______________| | |
|___shake_word__| (if needed) <-----phhMac | |
rgfgr--->|_____________--|-----------------------------/ |
pfgrFree->|___________----|--\ |
|_____________--|--|----------------------------/
/--|--_____________|<-/
\->|_____________--|-->NULL
rgfgr can be indexed as an array with ifgrMac elements.
The finger table slots are each one word in size.
Putting the finger table at the high end of memory relies on the coding of
of the CompactHeap routine; it moves the allocated blocks to low memory.
The free list is threaded with addresses, NOT indexes.
cw for a hunk includes size of header
cw for a free hunk is negative the size of the hunk
pfgr user's pointer to finger
fgr pointer to hunk of whatever
phh pointer to hunk header
phhPrevs move toward the bottom of the free list
phhNexts move toward the top
phhFree should always have a phhNext of NULL (i.e. the list is just double,
not circular).
_________________
|______cw_______|
pph -----> ph ----------->| . |
(FGR *) (FGR) | . |
| . |
|_______________|
_________________
phh ----->|______cw_______|
|___phhNext_____|
|___phhPrev_____|
| . |
| . |
| . |
|_______________|
#endif
typedef int *FGR; /* definitions for finger-related stuff. */
typedef int **PFGR;
/* storage allocator related stuff */
struct _HH
{
int cw;
struct _HH *phhNext;
struct _HH *phhPrev;
};
typedef struct _HH HH;
#ifdef OURHEAP
/* MACROS */
#define CwOfPfgr(pFgr) (*(*(pFgr) + bhh))
#define CwOfPhh(phh) ((phh)->cw)
#ifdef DEBUG
#define fPointsFgrTbl(pfgr) (((FGR *)(pfgr) >= rgfgr) && ((FGR *)(pfgr) < pfgrMac))
#endif
FGR *PfgrAllocate();
FGR *PfgrCopy();
extern ENV envMem;
#define cwof(i) ((sizeof(i)+sizeof(int)-1)/sizeof(int))
#endif /* OURHEAP */
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