memutils.h

/*-------------------------------------------------------------------------
 *
 * memutils.h--
 *    this file contains general memory alignment, allocation
 *    and manipulation stuff that used to be spread out
 *    between the following files:
 *
 *	align.h				alignment macros
 *	aset.h				memory allocation set stuff
 *	oset.h				  (used by aset.h)
 *	(bit.h				bit array type / extern)
 *	clib.h				mem routines
 *	limit.h				max bits/byte, etc.
 *
 *
 * Copyright (c) 1994, Regents of the University of California
 *
 * $Id: memutils.h,v 1.8 1997/08/20 14:54:35 momjian Exp $
 *
 * NOTES
 *    some of the information in this file will be moved to
 *    other files, (like MaxHeapTupleSize and MaxAttributeSize).
 *
 *-------------------------------------------------------------------------
 */
#ifndef MEMUTILS_H
#define MEMUTILS_H


#ifdef NOT_USED
/*****************************************************************************
 *	align.h		- alignment macros                                   *
 ****************************************************************************
 [TRH] Let the compiler decide what alignment it uses instead of  
tending
   we know better.
   GCC (at least v2.5.8 and up) has an __alignof__ keyword.
   However, we cannot use it here since on some architectures it reports
   just a _recommended_ alignment instead of the actual alignment used in
   padding structures (or at least, this is how I understand gcc's  
s...)
   So define a macro that gives us the _actual_ alignment inside a struct.
   {{note: assumes that alignment size is always a power of 2.}}
 */
#define _ALIGNSIZE(TYPE)	offsetof(struct { char __c; TYPE __t;}, __t)
#define _ALIGN(TYPE, LEN) \
	(((long)(LEN) + (_ALIGNSIZE(TYPE) - 1)) & ~(_ALIGNSIZE(TYPE) - 1))
#define SHORTALIGN(LEN)		_ALIGN(short, (LEN))
#define INTALIGN(LEN)		_ALIGN(int, (LEN))
#define LONGALIGN(LEN)		_ALIGN(long, (LEN))
#define DOUBLEALIGN(LEN)	_ALIGN(double, (LEN))
#define MAXALIGN(LEN)		_ALIGN(double, (LEN))

#endif /* 0 */

/*
 *	SHORTALIGN(LEN)	- length (or address) aligned for shorts
 */
#define	SHORTALIGN(LEN)\
	(((long)(LEN) + (sizeof (short) - 1)) & ~(sizeof (short) - 1))

#define INTALIGN(LEN)\
	(((long)(LEN) + (sizeof (int) - 1)) & ~(sizeof (int) -1))

/*
 *	LONGALIGN(LEN)	- length (or address) aligned for longs
 */
#if defined(sun) && ! defined(sparc)
#define	LONGALIGN(LEN)	SHORTALIGN(LEN)
#elif defined (alpha) || defined(linuxalpha)
     /* even though "long alignment" should really be on 8-byte boundaries
      * for linuxalpha, we want the strictest alignment to be on 4-byte (int) 
      * boundaries, because otherwise things break when they try to use the
      * FormData_pg_* structures.  --djm 12/12/96
      */
#define	LONGALIGN(LEN)\
	(((long)(LEN) + (sizeof (int) - 1)) & ~(sizeof (int) -1))
#else
#define	LONGALIGN(LEN)\
	(((long)(LEN) + (sizeof (long) - 1)) & ~(sizeof (long) -1))
#endif

#define DOUBLEALIGN(LEN)\
	(((long)(LEN) + (sizeof (double) - 1)) & ~(sizeof (double) -1))

#define MAXALIGN(LEN)\
	(((long)(LEN) + (sizeof (double) - 1)) & ~(sizeof (double) -1))

/*****************************************************************************
 *    oset.h -- 	Fixed format ordered set definitions.                *
 *****************************************************************************/
/* Note:
 *	Fixed format ordered sets are <EXPLAIN>.
 *	XXX This is a preliminary version.  Work is needed to explain
 *	XXX semantics of the external definitions.  Otherwise, the
 *	XXX functional interface should not change.
 *
 */

typedef struct OrderedElemData OrderedElemData;
typedef OrderedElemData* OrderedElem;

typedef struct OrderedSetData OrderedSetData;
typedef OrderedSetData* OrderedSet;

struct OrderedElemData {
    OrderedElem	next;	/* Next elem or &this->set->dummy	*/
    OrderedElem	prev;	/* Previous elem or &this->set->head	*/
    OrderedSet	set;	/* Parent set				*/
};

struct OrderedSetData {
    OrderedElem	head;	/* First elem or &this->dummy		*/
    OrderedElem	dummy;	/* (hack) Terminator == NULL		*/
    OrderedElem	tail;	/* Last elem or &this->head		*/
    Offset	offset;	/* Offset from struct base to elem	*/
    /* this could be signed short int! */
};

extern void OrderedSetInit(OrderedSet set, Offset offset);
extern bool OrderedSetContains(OrderedSet set, OrderedElem elem);
extern Pointer OrderedSetGetHead(OrderedSet set);
extern Pointer OrderedElemGetPredecessor(OrderedElem elem);
extern Pointer OrderedElemGetSuccessor(OrderedElem elem);
extern void  OrderedElemPop(OrderedElem elem);
extern void OrderedElemPushInto(OrderedElem elem, OrderedSet Set);

/*****************************************************************************
 *    aset.h --		Allocation set definitions.                          *
 *****************************************************************************/
/*
 * Description:
 *	An allocation set is a set containing allocated elements.  When
 *	an allocation is requested for a set, memory is allocated and a
 *	pointer is returned.  Subsequently, this memory may be freed or
 *	reallocated.  In addition, an allocation set may be reset which
 *	will cause all allocated memory to be freed.
 *
 *	Allocations may occur in four different modes.  The mode of
 *	allocation does not affect the behavior of allocations except in
 *	terms of performance.  The allocation mode is set at the time of
 *	set initialization.  Once the mode is chosen, it cannot be changed
 *	unless the set is reinitialized.
 *
 *	"Dynamic" mode forces all allocations to occur in a heap.  This
 *	is a good mode to use when small memory segments are allocated
 *	and freed very frequently.  This is a good choice when allocation
 *	characteristics are unknown.  This is the default mode.
 *
 *	"Static" mode attemts to allocate space as efficiently as possible
 *	without regard to freeing memory.  This mode should be chosen only
 *	when it is known that many allocations will occur but that very
 *	little of the allocated memory will be explicitly freed.
 *
 *	"Tunable" mode is a hybrid of dynamic and static modes.  The
 *	tunable mode will use static mode allocation except when the
 *	allocation request exceeds a size limit supplied at the time of set
 *	initialization.  "Big" objects are allocated using dynamic mode.
 *
 *	"Bounded" mode attempts to allocate space efficiently given a limit
 *	on space consumed by the allocation set.  This restriction can be
 *	considered a "soft" restriction, because memory segments will
 *	continue to be returned after the limit is exceeded.  The limit is
 *	specified at the time of set initialization like for tunable mode.
 *
 * Note:
 *	Allocation sets are not automatically reset on a system reset.
 *	Higher level code is responsible for cleaning up.
 *
 *	There may other modes in the future.
 */

/*
 * AllocPointer --
 *	Aligned pointer which may be a member of an allocation set.
 */
typedef Pointer AllocPointer;

/*
 * AllocMode --
 *	Mode of allocation for an allocation set.
 *
 * Note:
 *	See above for a description of the various nodes.
 */
typedef enum AllocMode {
    DynamicAllocMode,	/* always dynamically allocate */
    StaticAllocMode,	/* always "statically" allocate */
    TunableAllocMode,	/* allocations are "tuned" */
    BoundedAllocMode	/* allocations bounded to fixed usage */
} AllocMode;

#define DefaultAllocMode	DynamicAllocMode

/*
 * AllocSet --
 *	Allocation set.
 */
typedef struct AllocSetData {
    OrderedSetData	setData;
	/* Note: this will change in the future to support other modes */
} AllocSetData;

typedef AllocSetData *AllocSet;

/*
 * AllocPointerIsValid --
 *	True iff pointer is valid allocation pointer.
 */
#define AllocPointerIsValid(pointer) PointerIsValid(pointer)

/*
 * AllocSetIsValid --
 *	True iff set is valid allocation set.
 */
#define AllocSetIsValid(set) PointerIsValid(set)    

extern void AllocSetInit(AllocSet set, AllocMode mode, Size limit);

extern void AllocSetReset(AllocSet set);

extern bool AllocSetContains(AllocSet set, AllocPointer pointer);
extern AllocPointer AllocSetAlloc(AllocSet set, Size size);
extern void AllocSetFree(AllocSet set, AllocPointer pointer);
extern AllocPointer AllocSetRealloc(AllocSet set, AllocPointer pointer, 
				    Size size);

extern void AllocSetDump(AllocSet set);

/*****************************************************************************
 *    clib.h --		Standard C library definitions                       *
 *****************************************************************************/
/*
 * Note:
 *	This file is OPERATING SYSTEM dependent!!!
 *
 */

/* 
 *	LibCCopyLength is only used within this file. -cim 6/12/90
 * 
 */
typedef int	LibCCopyLength;

/*
 * MemoryCopy --
 *	Copies fixed length block of memory to another.
 */
#define MemoryCopy(toBuffer, fromBuffer, length)\
    memcpy(toBuffer, fromBuffer, length)

/*****************************************************************************
 *    limit.h --	POSTGRES limit definitions.                          *
 *****************************************************************************/

#define MaxBitsPerByte	8

typedef uint32	AttributeSize;	/* XXX should be defined elsewhere */

#define MaxHeapTupleSize	0x7fffffff
#define MaxAttributeSize	0x7fffffff

#define MaxIndexAttributeNumber	7


#endif /* MEMUTILS_H */