euctotc.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.
 *
 *----------------------------------------------------------------------
 */

/*
 *	euctotc.c (libtcstr)
 *
 *	W	euctotc(TC *tc, const UB *euc)
 *
 *	Convert an EUC character in euc area into a TC character and store it in tc.
 *	Return the number of converted bytes (1 or 2) as a function value.
 *	If tc == NULL, do not store the conversion result, but return a correct function value.
 *	If the character cannot be converted, return the function value "-1"; if euc is an empty string, return the function value "0".
 */

#include <basic.h>
#include <tstring.h>

#define TSD_ETC_VAL_0XA0	0xa0
#define TSD_ETC_VAL_0XE0	0xe0
#define TSD_ETC_MSK_0X7F	0x7fU
#define TSD_ETC_MSK_0XFF	0xffU
#define TSD_ETC_MSK_0X7F7F	0x7f7fU
#define TSD_ETC_SFT_8		8U
#define TSD_ETC_RTN_2		2
#define TSD_ETC_RTN_M1		(-1)

#define TSD_ETC_VAL_0X8E	0x8e
#define TSD_ETC_MSK_0X80	0x80U

IMPORT	const TC	_hzkana[];

EXPORT	W	euctotc( TC *tc, const UB *euc )
{
	W	ec;

	ec = (W)*(euc++);
	if (ec == TSD_ETC_VAL_0X8E) {
		ec = (W)*euc;
		if ((ec < TSD_ETC_VAL_0XA0 )||( ec >= TSD_ETC_VAL_0XE0)) {
			return TSD_ETC_RTN_M1;
		}
		/* Single-width katakana */
		if (tc != 0) {
			*tc = _hzkana[ec - TSD_ETC_VAL_0XA0];
		}
		return TSD_ETC_RTN_2;
	}
	if (((UW)ec & TSD_ETC_MSK_0X80) != 0) {
		if ((*euc & TSD_ETC_MSK_0X80) == 0) {
			return TSD_ETC_RTN_M1;
		}
		/* Double-width */
		if (tc != 0) {
			*tc = (TC)((((UW)ec << TSD_ETC_SFT_8) | (UH)(*euc & TSD_ETC_MSK_0XFF)) & TSD_ETC_MSK_0X7F7F);
		}
		return TSD_ETC_RTN_2;
	}
	if (ec == 0) {
		return 0;
	}
	if (tc != 0) {
		*tc = _asctotc[(UW)ec & TSD_ETC_MSK_0X7F];
	}
	return 1;
}