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/*-------------------------------------------------------------------------
*
* palloc.h
* POSTGRES memory allocator definitions.
*
* This file contains the basic memory allocation interface that is
* needed by almost every backend module. It is included directly by
* postgres.h, so the definitions here are automatically available
* everywhere. Keep it lean!
*
* Memory allocation occurs within "contexts". Every chunk obtained from
* palloc()/MemoryContextAlloc() is allocated within a specific context.
* The entire contents of a context can be freed easily and quickly by
* resetting or deleting the context --- this is both faster and less
* prone to memory-leakage bugs than releasing chunks individually.
* We organize contexts into context trees to allow fine-grain control
* over chunk lifetime while preserving the certainty that we will free
* everything that should be freed. See utils/mmgr/README for more info.
*
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: palloc.h,v 1.13 2000/06/28 03:33:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#ifndef PALLOC_H
#define PALLOC_H
/*
* Type MemoryContextData is declared in nodes/memnodes.h. Most users
* of memory allocation should just treat it as an abstract type, so we
* do not provide the struct contents here.
*/
typedef struct MemoryContextData *MemoryContext;
/*
* CurrentMemoryContext is the default allocation context for palloc().
* We declare it here so that palloc() can be a macro. Avoid accessing it
* directly! Instead, use MemoryContextSwitchTo() to change the setting.
*/
extern DLLIMPORT MemoryContext CurrentMemoryContext;
/*
* Fundamental memory-allocation operations (more are in utils/memutils.h)
*/
extern void *MemoryContextAlloc(MemoryContext context, Size size);
#define palloc(sz) MemoryContextAlloc(CurrentMemoryContext, (sz))
extern void pfree(void *pointer);
extern void *repalloc(void *pointer, Size size);
extern MemoryContext MemoryContextSwitchTo(MemoryContext context);
/*
* These are like standard strdup() except the copied string is
* allocated in a context, not with malloc().
*/
extern char *MemoryContextStrdup(MemoryContext context, const char *string);
#define pstrdup(str) MemoryContextStrdup(CurrentMemoryContext, (str))
/* ----------------
* Alignment macros: align a length or address appropriately for a given type.
*
* There used to be some incredibly crufty platform-dependent hackery here,
* but now we rely on the configure script to get the info for us. Much nicer.
*
* NOTE: TYPEALIGN will not work if ALIGNVAL is not a power of 2.
* That case seems extremely unlikely to occur in practice, however.
* ----------------
*/
#define TYPEALIGN(ALIGNVAL,LEN) (((long)(LEN) + (ALIGNVAL-1)) & ~(ALIGNVAL-1))
#define SHORTALIGN(LEN) TYPEALIGN(ALIGNOF_SHORT, (LEN))
#define INTALIGN(LEN) TYPEALIGN(ALIGNOF_INT, (LEN))
#define LONGALIGN(LEN) TYPEALIGN(ALIGNOF_LONG, (LEN))
#define DOUBLEALIGN(LEN) TYPEALIGN(ALIGNOF_DOUBLE, (LEN))
#define MAXALIGN(LEN) TYPEALIGN(MAXIMUM_ALIGNOF, (LEN))
#endif /* PALLOC_H */
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