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267 lines
9.1 KiB
C
267 lines
9.1 KiB
C
/*-------------------------------------------------------------------------
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*
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* memutils.h--
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* this file contains general memory alignment, allocation
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* and manipulation stuff that used to be spread out
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* between the following files:
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*
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* align.h alignment macros
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* aset.h memory allocation set stuff
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* oset.h (used by aset.h)
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* (bit.h bit array type / extern)
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* clib.h mem routines
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* limit.h max bits/byte, etc.
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*
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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* $Id: memutils.h,v 1.8 1997/08/20 14:54:35 momjian Exp $
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*
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* NOTES
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* some of the information in this file will be moved to
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* other files, (like MaxHeapTupleSize and MaxAttributeSize).
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef MEMUTILS_H
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#define MEMUTILS_H
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#ifdef NOT_USED
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/*****************************************************************************
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* align.h - alignment macros *
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****************************************************************************
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[TRH] Let the compiler decide what alignment it uses instead of
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tending
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we know better.
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GCC (at least v2.5.8 and up) has an __alignof__ keyword.
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However, we cannot use it here since on some architectures it reports
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just a _recommended_ alignment instead of the actual alignment used in
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padding structures (or at least, this is how I understand gcc's
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s...)
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So define a macro that gives us the _actual_ alignment inside a struct.
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{{note: assumes that alignment size is always a power of 2.}}
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*/
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#define _ALIGNSIZE(TYPE) offsetof(struct { char __c; TYPE __t;}, __t)
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#define _ALIGN(TYPE, LEN) \
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(((long)(LEN) + (_ALIGNSIZE(TYPE) - 1)) & ~(_ALIGNSIZE(TYPE) - 1))
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#define SHORTALIGN(LEN) _ALIGN(short, (LEN))
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#define INTALIGN(LEN) _ALIGN(int, (LEN))
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#define LONGALIGN(LEN) _ALIGN(long, (LEN))
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#define DOUBLEALIGN(LEN) _ALIGN(double, (LEN))
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#define MAXALIGN(LEN) _ALIGN(double, (LEN))
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#endif /* 0 */
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/*
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* SHORTALIGN(LEN) - length (or address) aligned for shorts
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*/
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#define SHORTALIGN(LEN)\
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(((long)(LEN) + (sizeof (short) - 1)) & ~(sizeof (short) - 1))
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#define INTALIGN(LEN)\
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(((long)(LEN) + (sizeof (int) - 1)) & ~(sizeof (int) -1))
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/*
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* LONGALIGN(LEN) - length (or address) aligned for longs
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*/
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#if defined(sun) && ! defined(sparc)
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#define LONGALIGN(LEN) SHORTALIGN(LEN)
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#elif defined (alpha) || defined(linuxalpha)
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/* even though "long alignment" should really be on 8-byte boundaries
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* for linuxalpha, we want the strictest alignment to be on 4-byte (int)
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* boundaries, because otherwise things break when they try to use the
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* FormData_pg_* structures. --djm 12/12/96
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*/
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#define LONGALIGN(LEN)\
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(((long)(LEN) + (sizeof (int) - 1)) & ~(sizeof (int) -1))
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#else
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#define LONGALIGN(LEN)\
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(((long)(LEN) + (sizeof (long) - 1)) & ~(sizeof (long) -1))
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#endif
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#define DOUBLEALIGN(LEN)\
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(((long)(LEN) + (sizeof (double) - 1)) & ~(sizeof (double) -1))
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#define MAXALIGN(LEN)\
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(((long)(LEN) + (sizeof (double) - 1)) & ~(sizeof (double) -1))
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/*****************************************************************************
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* oset.h -- Fixed format ordered set definitions. *
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*****************************************************************************/
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/* Note:
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* Fixed format ordered sets are <EXPLAIN>.
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* XXX This is a preliminary version. Work is needed to explain
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* XXX semantics of the external definitions. Otherwise, the
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* XXX functional interface should not change.
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*
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*/
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typedef struct OrderedElemData OrderedElemData;
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typedef OrderedElemData* OrderedElem;
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typedef struct OrderedSetData OrderedSetData;
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typedef OrderedSetData* OrderedSet;
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struct OrderedElemData {
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OrderedElem next; /* Next elem or &this->set->dummy */
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OrderedElem prev; /* Previous elem or &this->set->head */
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OrderedSet set; /* Parent set */
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};
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struct OrderedSetData {
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OrderedElem head; /* First elem or &this->dummy */
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OrderedElem dummy; /* (hack) Terminator == NULL */
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OrderedElem tail; /* Last elem or &this->head */
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Offset offset; /* Offset from struct base to elem */
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/* this could be signed short int! */
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};
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extern void OrderedSetInit(OrderedSet set, Offset offset);
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extern bool OrderedSetContains(OrderedSet set, OrderedElem elem);
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extern Pointer OrderedSetGetHead(OrderedSet set);
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extern Pointer OrderedElemGetPredecessor(OrderedElem elem);
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extern Pointer OrderedElemGetSuccessor(OrderedElem elem);
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extern void OrderedElemPop(OrderedElem elem);
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extern void OrderedElemPushInto(OrderedElem elem, OrderedSet Set);
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/*****************************************************************************
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* aset.h -- Allocation set definitions. *
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*****************************************************************************/
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/*
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* Description:
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* An allocation set is a set containing allocated elements. When
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* an allocation is requested for a set, memory is allocated and a
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* pointer is returned. Subsequently, this memory may be freed or
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* reallocated. In addition, an allocation set may be reset which
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* will cause all allocated memory to be freed.
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*
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* Allocations may occur in four different modes. The mode of
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* allocation does not affect the behavior of allocations except in
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* terms of performance. The allocation mode is set at the time of
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* set initialization. Once the mode is chosen, it cannot be changed
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* unless the set is reinitialized.
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*
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* "Dynamic" mode forces all allocations to occur in a heap. This
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* is a good mode to use when small memory segments are allocated
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* and freed very frequently. This is a good choice when allocation
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* characteristics are unknown. This is the default mode.
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*
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* "Static" mode attemts to allocate space as efficiently as possible
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* without regard to freeing memory. This mode should be chosen only
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* when it is known that many allocations will occur but that very
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* little of the allocated memory will be explicitly freed.
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*
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* "Tunable" mode is a hybrid of dynamic and static modes. The
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* tunable mode will use static mode allocation except when the
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* allocation request exceeds a size limit supplied at the time of set
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* initialization. "Big" objects are allocated using dynamic mode.
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*
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* "Bounded" mode attempts to allocate space efficiently given a limit
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* on space consumed by the allocation set. This restriction can be
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* considered a "soft" restriction, because memory segments will
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* continue to be returned after the limit is exceeded. The limit is
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* specified at the time of set initialization like for tunable mode.
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*
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* Note:
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* Allocation sets are not automatically reset on a system reset.
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* Higher level code is responsible for cleaning up.
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*
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* There may other modes in the future.
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*/
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/*
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* AllocPointer --
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* Aligned pointer which may be a member of an allocation set.
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*/
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typedef Pointer AllocPointer;
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/*
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* AllocMode --
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* Mode of allocation for an allocation set.
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*
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* Note:
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* See above for a description of the various nodes.
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*/
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typedef enum AllocMode {
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DynamicAllocMode, /* always dynamically allocate */
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StaticAllocMode, /* always "statically" allocate */
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TunableAllocMode, /* allocations are "tuned" */
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BoundedAllocMode /* allocations bounded to fixed usage */
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} AllocMode;
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#define DefaultAllocMode DynamicAllocMode
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/*
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* AllocSet --
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* Allocation set.
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*/
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typedef struct AllocSetData {
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OrderedSetData setData;
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/* Note: this will change in the future to support other modes */
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} AllocSetData;
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typedef AllocSetData *AllocSet;
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/*
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* AllocPointerIsValid --
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* True iff pointer is valid allocation pointer.
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*/
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#define AllocPointerIsValid(pointer) PointerIsValid(pointer)
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/*
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* AllocSetIsValid --
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* True iff set is valid allocation set.
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*/
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#define AllocSetIsValid(set) PointerIsValid(set)
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extern void AllocSetInit(AllocSet set, AllocMode mode, Size limit);
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extern void AllocSetReset(AllocSet set);
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extern bool AllocSetContains(AllocSet set, AllocPointer pointer);
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extern AllocPointer AllocSetAlloc(AllocSet set, Size size);
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extern void AllocSetFree(AllocSet set, AllocPointer pointer);
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extern AllocPointer AllocSetRealloc(AllocSet set, AllocPointer pointer,
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Size size);
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extern void AllocSetDump(AllocSet set);
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/*****************************************************************************
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* clib.h -- Standard C library definitions *
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*****************************************************************************/
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/*
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* Note:
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* This file is OPERATING SYSTEM dependent!!!
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*
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*/
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/*
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* LibCCopyLength is only used within this file. -cim 6/12/90
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*
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*/
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typedef int LibCCopyLength;
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/*
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* MemoryCopy --
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* Copies fixed length block of memory to another.
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*/
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#define MemoryCopy(toBuffer, fromBuffer, length)\
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memcpy(toBuffer, fromBuffer, length)
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/*****************************************************************************
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* limit.h -- POSTGRES limit definitions. *
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*****************************************************************************/
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#define MaxBitsPerByte 8
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typedef uint32 AttributeSize; /* XXX should be defined elsewhere */
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#define MaxHeapTupleSize 0x7fffffff
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#define MaxAttributeSize 0x7fffffff
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#define MaxIndexAttributeNumber 7
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#endif /* MEMUTILS_H */
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