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#ifdef WITH_UNICODE
/*
 * Copyright 2001-2004 Unicode, Inc.
 *
 * Disclaimer
 *
 * This source code is provided as is by Unicode, Inc. No claims are
 * made as to fitness for any particular purpose. No warranties of any
 * kind are expressed or implied. The recipient agrees to determine
 * applicability of information provided. If this file has been
 * purchased on magnetic or optical media from Unicode, Inc., the
 * sole remedy for any claim will be exchange of defective media
 * within 90 days of receipt.
 *
 * Limitations on Rights to Redistribute This Code
 *
 * Unicode, Inc. hereby grants the right to freely use the information
 * supplied in this file in the creation of products supporting the
 * Unicode Standard, and to make copies of this file in any form
 * for internal or external distribution as long as this notice
 * remains attached.
 */
/*
 * NOTE: The original version of this code can be found at
 *   http://www.unicode.org/Public/PROGRAMS/CVTUTF/
 * This version was slightly modified to allow ConvertUTF8toUTF16 and
 * ConvertUTF16toUTF8 to calculate the bytes required without writing to
 * the target buffer.
 *
 */
/* ---------------------------------------------------------------------

    Conversions between UTF32, UTF-16, and UTF-8. Source code file.
    Author: Mark E. Davis, 1994.
    Rev History: Rick McGowan, fixes & updates May 2001.
    Sept 2001: fixed const & error conditions per
	mods suggested by S. Parent & A. Lillich.
    June 2002: Tim Dodd added detection and handling of incomplete
	source sequences, enhanced error detection, added casts
	to eliminate compiler warnings.
    July 2003: slight mods to back out aggressive FFFE detection.
    Jan 2004: updated switches in from-UTF8 conversions.
    Oct 2004: updated to use UNI_MAX_LEGAL_UTF32 in UTF-32 conversions.

    See the header file "ConvertUTF.h" for complete documentation.

------------------------------------------------------------------------ */


#include "ConvertUTF.h"
#ifdef CVTUTF_DEBUG
#include <stdio.h>
#endif

static const int halfShift  = 10; /* used for shifting by 10 bits */

static const UTF32 halfBase = 0x0010000UL;
static const UTF32 halfMask = 0x3FFUL;

#define UNI_SUR_HIGH_START  (UTF32)0xD800
#define UNI_SUR_HIGH_END    (UTF32)0xDBFF
#define UNI_SUR_LOW_START   (UTF32)0xDC00
#define UNI_SUR_LOW_END     (UTF32)0xDFFF
#define false	   0
#define true	    1

/* --------------------------------------------------------------------- */

ConversionResult ConvertUTF32toUTF16 (
	const UTF32** sourceStart, const UTF32* sourceEnd,
	UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags) {
    ConversionResult result = conversionOK;
    const UTF32* source = *sourceStart;
    UTF16* target = *targetStart;
    while (source < sourceEnd) {
	UTF32 ch;
	if (target >= targetEnd) {
	    result = targetExhausted; break;
	}
	ch = *source++;
	if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
	    /* UTF-16 surrogate values are illegal in UTF-32; 0xffff or 0xfffe are both reserved values */
	    if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
		if (flags == strictConversion) {
		    --source; /* return to the illegal value itself */