smgrtype.c

来自「PostgreSQL7.4.6 for Linux」· C语言 代码 · 共 85 行

/*-------------------------------------------------------------------------
 *
 * smgrtype.c
 *	  storage manager type
 *
 * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/storage/smgr/smgrtype.c,v 1.21 2003/08/04 02:40:04 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "storage/smgr.h"

typedef struct smgrid
{
	char	   *smgr_name;
} smgrid;

/*
 *	StorageManager[] -- List of defined storage managers.
 *
 *		The weird comma placement is to keep compilers happy no matter
 *		which of these is (or is not) defined.
 */

static smgrid StorageManager[] = {
	{"magnetic disk"},
#ifdef STABLE_MEMORY_STORAGE
	{"main memory"}
#endif
};

static int	NStorageManagers = lengthof(StorageManager);

Datum
smgrin(PG_FUNCTION_ARGS)
{
	char	   *s = PG_GETARG_CSTRING(0);
	int16		i;

	for (i = 0; i < NStorageManagers; i++)
	{
		if (strcmp(s, StorageManager[i].smgr_name) == 0)
			PG_RETURN_INT16(i);
	}
	elog(ERROR, "unrecognized storage manager name \"%s\"", s);
	PG_RETURN_INT16(0);
}

Datum
smgrout(PG_FUNCTION_ARGS)
{
	int16		i = PG_GETARG_INT16(0);
	char	   *s;

	if (i >= NStorageManagers || i < 0)
		elog(ERROR, "invalid storage manager id: %d", i);

	s = pstrdup(StorageManager[i].smgr_name);
	PG_RETURN_CSTRING(s);
}

Datum
smgreq(PG_FUNCTION_ARGS)
{
	int16		a = PG_GETARG_INT16(0);
	int16		b = PG_GETARG_INT16(1);

	PG_RETURN_BOOL(a == b);
}

Datum
smgrne(PG_FUNCTION_ARGS)
{
	int16		a = PG_GETARG_INT16(0);
	int16		b = PG_GETARG_INT16(1);

	PG_RETURN_BOOL(a != b);
}