/*-------------------------------------------------------------------------
 *
 * bool.c
 *	  Functions for the built-in type "bool".
 *
 * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/bool.c,v 1.26 2002/06/20 20:29:36 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include "utils/builtins.h"

/*****************************************************************************
 *	 USER I/O ROUTINES														 *
 *****************************************************************************/

/*
 *		boolin			- converts "t" or "f" to 1 or 0
 *
 * Check explicitly for "true/false" and TRUE/FALSE, 1/0, YES/NO.
 * Reject other values. - thomas 1997-10-05
 *
 * In the switch statement, check the most-used possibilities first.
 */
Datum
boolin(PG_FUNCTION_ARGS)
{
	char	   *b = PG_GETARG_CSTRING(0);

	switch (*b)
	{
		case 't':
		case 'T':
			if (strncasecmp(b, "true", strlen(b)) == 0)
				PG_RETURN_BOOL(true);
			break;

		case 'f':
		case 'F':
			if (strncasecmp(b, "false", strlen(b)) == 0)
				PG_RETURN_BOOL(false);
			break;

		case 'y':
		case 'Y':
			if (strncasecmp(b, "yes", strlen(b)) == 0)
				PG_RETURN_BOOL(true);
			break;

		case '1':
			if (strncasecmp(b, "1", strlen(b)) == 0)
				PG_RETURN_BOOL(true);
			break;

		case 'n':
		case 'N':
			if (strncasecmp(b, "no", strlen(b)) == 0)
				PG_RETURN_BOOL(false);
			break;

		case '0':
			if (strncasecmp(b, "0", strlen(b)) == 0)
				PG_RETURN_BOOL(false);
			break;

		default:
			break;
	}

	elog(ERROR, "Bad boolean external representation '%s'", b);

	/* not reached */
	PG_RETURN_BOOL(false);
}

/*
 *		boolout			- converts 1 or 0 to "t" or "f"
 */
Datum
boolout(PG_FUNCTION_ARGS)
{
	bool		b = PG_GETARG_BOOL(0);
	char	   *result = (char *) palloc(2);

	result[0] = (b) ? 't' : 'f';
	result[1] = '\0';
	PG_RETURN_CSTRING(result);
}


/*****************************************************************************
 *	 PUBLIC ROUTINES														 *
 *****************************************************************************/

Datum
booleq(PG_FUNCTION_ARGS)
{
	bool		arg1 = PG_GETARG_BOOL(0);
	bool		arg2 = PG_GETARG_BOOL(1);

	PG_RETURN_BOOL(arg1 == arg2);
}

Datum
boolne(PG_FUNCTION_ARGS)
{
	bool		arg1 = PG_GETARG_BOOL(0);
	bool		arg2 = PG_GETARG_BOOL(1);

	PG_RETURN_BOOL(arg1 != arg2);
}

Datum
boollt(PG_FUNCTION_ARGS)
{
	bool		arg1 = PG_GETARG_BOOL(0);
	bool		arg2 = PG_GETARG_BOOL(1);

	PG_RETURN_BOOL(arg1 < arg2);
}

Datum
boolgt(PG_FUNCTION_ARGS)
{
	bool		arg1 = PG_GETARG_BOOL(0);
	bool		arg2 = PG_GETARG_BOOL(1);

	PG_RETURN_BOOL(arg1 > arg2);
}

Datum
boolle(PG_FUNCTION_ARGS)
{
	bool		arg1 = PG_GETARG_BOOL(0);
	bool		arg2 = PG_GETARG_BOOL(1);

	PG_RETURN_BOOL(arg1 <= arg2);
}

Datum
boolge(PG_FUNCTION_ARGS)
{
	bool		arg1 = PG_GETARG_BOOL(0);
	bool		arg2 = PG_GETARG_BOOL(1);

	PG_RETURN_BOOL(arg1 >= arg2);
}

/*
 * Per SQL92, istrue() and isfalse() should return false, not NULL,
 * when presented a NULL input (since NULL is our implementation of
 * UNKNOWN).  Conversely isnottrue() and isnotfalse() should return true.
 * Therefore, these routines are all declared not-strict in pg_proc
 * and must do their own checking for null inputs.
 *
 * Note we don't need isunknown() and isnotunknown() functions, since
 * nullvalue() and nonnullvalue() will serve.
 */

Datum
istrue(PG_FUNCTION_ARGS)
{
	bool		b;

	if (PG_ARGISNULL(0))
		PG_RETURN_BOOL(false);

	b = PG_GETARG_BOOL(0);

	PG_RETURN_BOOL(b);
}

Datum
isfalse(PG_FUNCTION_ARGS)
{
	bool		b;

	if (PG_ARGISNULL(0))
		PG_RETURN_BOOL(false);

	b = PG_GETARG_BOOL(0);

	PG_RETURN_BOOL(!b);
}

Datum
isnottrue(PG_FUNCTION_ARGS)
{
	bool		b;

	if (PG_ARGISNULL(0))
		PG_RETURN_BOOL(true);

	b = PG_GETARG_BOOL(0);

	PG_RETURN_BOOL(!b);
}

Datum
isnotfalse(PG_FUNCTION_ARGS)
{
	bool		b;

	if (PG_ARGISNULL(0))
		PG_RETURN_BOOL(true);

	b = PG_GETARG_BOOL(0);

	PG_RETURN_BOOL(b);
}