istlangce.c

T-kernel 的extension源代码

/*
 *----------------------------------------------------------------------
 *    T-Kernel / Standard Extension
 *
 *    Copyright (C) 2006 by Ken Sakamura. All rights reserved.
 *    T-Kernel / Standard Extension is distributed 
 *      under the T-License for T-Kernel / Standard Extension.
 *----------------------------------------------------------------------
 *
 *    Version:   1.00.00
 *    Released by T-Engine Forum(http://www.t-engine.org) at 2006/8/11.
 *
 *----------------------------------------------------------------------
 */

/*
 *	istlangce.c (libtcstr)
 */

#include <basic.h>
#include <tlang.h>
#include <cnvend.h>

#define TSD_ITE_LAN_M2	(-2)

/*
 * Determination of language (script) specification code
 *	Determine whether tp string is a language specification code.
 *	Use ConvEndianH() to perform endian conversion of tp character string for determination.
 *
 * Return value	> 0	Language specification code (TLANG is returned)
 *		= 0	Not language specification code
 *		= -1	Invalid language specification code
 *		= -2	Indefinite language specification code (The code is not complete)
 *
 *	len	Valid maximum length of tp character string (in TC)
 *		The length includes up to TNULL or len character.
 *		If 0 is specified, len is ignored and up to TNULL is included.
 *	ntp	Return the position of the character located next to the language specification code.
 *		Not returned if NULL is specified.
 *
 *	(Ex.)	FE21			Return value = 0x0021	*ntp = tp + 1
 *		FEFE 0021		Return value = 0x0121	*ntp = tp + 2
 *		2121			Return value = 0	*ntp = tp
 *		FE00			Return value = -1	*ntp = tp + 1
 *		FEFE 2121		Return value = -1	*ntp = tp + 2
 *		FEFE 0000		Return value = -2	*ntp = tp + 1
 *		FEFE 0021  (len = 1)	Return value = -2	*ntp = tp + 1
 */
EXPORT W isTLANGce( const TC *tp, W len, TC **ntp )
{
	W	n, lang;
	TC	c;

	lang = 0;
	n = 0;
	while ( (c = ConvEndianH(*tp)) != TNULL ) {

		lang = isTLANGch(c, &n);
		if ( lang == 0 ) {
			break;
		}
		tp++;
		if ( lang != TSD_ITE_LAN_M2 ) {
			break;
		}

		if ( --len == 0 ) {
			break;
		}
	}

	if ( ntp != NULL ) {
		*ntp = (TC*)tp;
	}
	return lang;
}