/*****************************************************************************\
*                                                                             *
 *  Name   : utf_conversion                                                    *
 *  Author : Unicode, Inc. (C conversion functions)                            *
 *  Author : Chris Koeritz (C++ conversion classes)                            *
 *                                                                             *
 *******************************************************************************
 * Copyright (c) 2006-$now By Author.  This program is free software; you can  *
 * redistribute it and/or modify it under the terms of the GNU General Public  *
 * License as published by the Free Software Foundation; either version 2 of   *
 * the License or (at your option) any later version.  This is online at:      *
 *     http://www.fsf.org/copyleft/gpl.html                                    *
 * Please send any updates to: fred@gruntose.com                               *
 \*****************************************************************************/

//copyright below is relevant to UTF conversion methods only.
/*
 * Copyright 2001-$now 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.
 */

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

 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 "astring.h"
#include "utf_conversion.h"

#include <string.h>
#include <wchar.h>
#ifdef CVTUTF_DEBUG
#include <stdio.h>
#endif

namespace basis {

	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

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

	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 */
						result = sourceIllegal;
						break;
					} else {
						*target++ = UNI_REPLACEMENT_CHAR;
					}
				} else {
					*target++ = (UTF16)ch; /* normal case */
				}
			} else if (ch > UNI_MAX_LEGAL_UTF32) {
				if (flags == strictConversion) {
					result = sourceIllegal;
				} else {
					*target++ = UNI_REPLACEMENT_CHAR;
				}
			} else {
				/* target is a character in range 0xFFFF - 0x10FFFF. */
				if (target + 1 >= targetEnd) {
					--source; /* Back up source pointer! */
					result = targetExhausted;
					break;
				}
				ch -= halfBase;
				*target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START );
				*target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START );
			}
		}
		*sourceStart = source;
		*targetStart = target;
		return result;
	}

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

	ConversionResult ConvertUTF16toUTF32(const UTF16** sourceStart, const UTF16* sourceEnd,
	  UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags)
	{
		ConversionResult result = conversionOK;
		const UTF16* source = *sourceStart;
		UTF32* target = *targetStart;
		UTF32 ch, ch2;
		while (source < sourceEnd) {
			const UTF16* oldSource = source; /*  In case we have to back up because of target overflow. */
			ch = *source++;
			/* If we have a surrogate pair, convert to UTF32 first. */
			if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) {
				/* If the 16 bits following the high surrogate are in the source buffer... */
				if (source < sourceEnd) {
					ch2 = *source;
					/* If it's a low surrogate, convert to UTF32. */
					if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
						ch = ((ch - UNI_SUR_HIGH_START ) << halfShift) + (ch2 - UNI_SUR_LOW_START )
						    + halfBase;
						++source;
					} else if (flags == strictConversion) { /* it's an unpaired high surrogate */
						--source; /* return to the illegal value itself */
						result = sourceIllegal;
						break;
					}
				} else { /* We don't have the 16 bits following the high surrogate. */
					--source; /* return to the high surrogate */
					result = sourceExhausted;
					break;
				}
			} else if (flags == strictConversion) {
				/* UTF-16 surrogate values are illegal in UTF-32 */
				if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
					--source; /* return to the illegal value itself */
					result = sourceIllegal;
					break;
				}
			}
			if (target >= targetEnd) {
				source = oldSource; /* Back up source pointer! */
				result = targetExhausted;
				break;
			}
			*target++ = ch;
		}
		*sourceStart = source;
		*targetStart = target;
#ifdef CVTUTF_DEBUG
		if (result == sourceIllegal) {
			fprintf(stderr, "ConvertUTF16toUTF32 illegal seq 0x%04x,%04x\n", ch, ch2);
			fflush(stderr);
		}
#endif
		return result;
	}

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

	/*
	 * Index into the table below with the first byte of a UTF-8 sequence to
	 * get the number of trailing bytes that are supposed to follow it.
	 * Note that *legal* UTF-8 values can't have 4 or 5-bytes. The table is
	 * left as-is for anyone who may want to do such conversion, which was
	 * allowed in earlier algorithms.
	 */
	static const char trailingBytesForUTF8[256] = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
	    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
	    1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2,
	    2, 2, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5 };

	/*
	 * Magic values subtracted from a buffer value during UTF8 conversion.
	 * This table contains as many values as there might be trailing bytes
	 * in a UTF-8 sequence.
	 */
	static const UTF32 offsetsFromUTF8[6] = { 0x00000000UL, 0x00003080UL, 0x000E2080UL,
	    0x03C82080UL, 0xFA082080UL, 0x82082080UL };

	/*
	 * Once the bits are split out into bytes of UTF-8, this is a mask OR-ed
	 * into the first byte, depending on how many bytes follow.  There are
	 * as many entries in this table as there are UTF-8 sequence types.
	 * (I.e., one byte sequence, two byte... etc.). Remember that sequencs
	 * for *legal* UTF-8 will be 4 or fewer bytes total.
	 */
	static const UTF8 firstByteMark[7] = { 0x00, 0x00, 0xC0, 0xE0, 0xF0, 0xF8, 0xFC };

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

	/* The interface converts a whole buffer to avoid function-call overhead.
	 * Constants have been gathered. Loops & conditionals have been removed as
	 * much as possible for efficiency, in favor of drop-through switches.
	 * (See "Note A" at the bottom of the file for equivalent code.)
	 * If your compiler supports it, the "isLegalUTF8" call can be turned
	 * into an inline function.
	 */

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

	ConversionResult ConvertUTF16toUTF8(const UTF16** sourceStart, const UTF16* sourceEnd,
	  UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags)
	{
		ConversionResult result = conversionOK;
		const UTF16* source = *sourceStart;
		UTF8* target = *targetStart;
		while (source < sourceEnd) {
			UTF32 ch;
			unsigned short bytesToWrite = 0;
			const UTF32 byteMask = 0xBF;
			const UTF32 byteMark = 0x80;
			const UTF16* oldSource = source; /* In case we have to back up because of target overflow. */
			ch = *source++;
			/* If we have a surrogate pair, convert to UTF32 first. */
			if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_HIGH_END) {
				/* If the 16 bits following the high surrogate are in the source buffer... */
				if (source < sourceEnd) {
					UTF32 ch2 = *source;
					/* If it's a low surrogate, convert to UTF32. */
					if (ch2 >= UNI_SUR_LOW_START && ch2 <= UNI_SUR_LOW_END) {
						ch = ((ch - UNI_SUR_HIGH_START ) << halfShift) + (ch2 - UNI_SUR_LOW_START )
						    + halfBase;
						++source;
					} else if (flags == strictConversion) { /* it's an unpaired high surrogate */
						--source; /* return to the illegal value itself */
						result = sourceIllegal;
						break;
					}
				} else { /* We don't have the 16 bits following the high surrogate. */
					--source; /* return to the high surrogate */
					result = sourceExhausted;
					break;
				}
			} else if (flags == strictConversion) {
				/* UTF-16 surrogate values are illegal in UTF-32 */
				if (ch >= UNI_SUR_LOW_START && ch <= UNI_SUR_LOW_END) {
					--source; /* return to the illegal value itself */
					result = sourceIllegal;
					break;
				}
			}
			/* Figure out how many bytes the result will require */
			if (ch < (UTF32)0x80) {
				bytesToWrite = 1;
			} else if (ch < (UTF32)0x800) {
				bytesToWrite = 2;
			} else if (ch < (UTF32)0x10000) {
				bytesToWrite = 3;
			} else if (ch < (UTF32)0x110000) {
				bytesToWrite = 4;
			} else {
				bytesToWrite = 3;
				ch = UNI_REPLACEMENT_CHAR;
			}

			target += bytesToWrite;
			if (target > targetEnd) {
				source = oldSource; /* Back up source pointer! */
				target -= bytesToWrite;
				result = targetExhausted;
				break;
			}
			switch (bytesToWrite) { /* note: everything falls through. */
				case 4:
					*--target = (UTF8)((ch | byteMark) & byteMask);
					ch >>= 6;
					// no break
				case 3:
					*--target = (UTF8)((ch | byteMark) & byteMask);
					ch >>= 6;
					// no break.
				case 2:
					*--target = (UTF8)((ch | byteMark) & byteMask);
					ch >>= 6;
					// no break.
				case 1:
					*--target = (UTF8)(ch | firstByteMark[bytesToWrite]);
					// no break.
			}
			target += bytesToWrite;
		}
		*sourceStart = source;
		*targetStart = target;
		return result;
	}

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

	/*
	 * Utility routine to tell whether a sequence of bytes is legal UTF-8.
	 * This must be called with the length pre-determined by the first byte.
	 * If not calling this from ConvertUTF8to*, then the length can be set by:
	 *  length = trailingBytesForUTF8[*source]+1;
	 * and the sequence is illegal right away if there aren't that many bytes
	 * available.
	 * If presented with a length > 4, this returns false.  The Unicode
	 * definition of UTF-8 goes up to 4-byte sequences.
	 */

	static Booleano isLegalUTF8(const UTF8 *source, int length)
	{
		UTF8 a;
		const UTF8 *srcptr = source + length;
		switch (length) {
			/* Everything else falls through when "true"... */
			case 4: {
				if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
			}
				/* no break */
			case 3: {
				if ((a = (*--srcptr)) < 0x80 || a > 0xBF) return false;
			}
				/* no break */
			case 2: {
				if ((a = (*--srcptr)) > 0xBF) return false;

				switch (*source) {
					/* no fall-through in this inner switch */
					case 0xE0:
						if (a < 0xA0) return false;
						break;
					case 0xED:
						if (a > 0x9F) return false;
						break;
					case 0xF0:
						if (a < 0x90) return false;
						break;
					case 0xF4:
						if (a > 0x8F) return false;
						break;
					default:
						if (a < 0x80) return false;
						break;
				}
			}
				/* no break */
			case 1: {
				if (*source >= 0x80 && *source < 0xC2) return false;
			}
				/* no break */
			default: {
				return false;
			}
		}
		if (*source > 0xF4) return false;
		return true;
	}

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

	/*
	 * Exported function to return whether a UTF-8 sequence is legal or not.
	 * This is not used here; it's just exported.
	 */
	Booleano isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd)
	{
		int length = trailingBytesForUTF8[*source] + 1;
		if (source + length > sourceEnd) {
			return false;
		}
		return isLegalUTF8(source, length);
	}

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

	ConversionResult ConvertUTF8toUTF16(const UTF8** sourceStart, const UTF8* sourceEnd,
	  UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags)
	{
		ConversionResult result = conversionOK;
		const UTF8* source = *sourceStart;
		UTF16* target = *targetStart;
		while (source < sourceEnd) {
			UTF32 ch = 0;
			unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
			if (source + extraBytesToRead >= sourceEnd) {
				result = sourceExhausted;
				break;
			}
			/* Do this check whether lenient or strict */
			if (!isLegalUTF8(source, extraBytesToRead + 1)) {
				result = sourceIllegal;
				break;
			}
			/*
			 * The cases all fall through. See "Note A" below.
			 */
			switch (extraBytesToRead) {
				case 5:
					ch += *source++;
					ch <<= 6; /* remember, illegal UTF-8 */
					/* no break */
				case 4:
					ch += *source++;
					ch <<= 6; /* remember, illegal UTF-8 */
					/* no break */
				case 3:
					ch += *source++;
					ch <<= 6;
					/* no break */
				case 2:
					ch += *source++;
					ch <<= 6;
					/* no break */
				case 1:
					ch += *source++;
					ch <<= 6;
					/* no break */
				case 0:
					ch += *source++;
					/* no break */
			}
			ch -= offsetsFromUTF8[extraBytesToRead];

			if (target >= targetEnd) {
				source -= (extraBytesToRead + 1); /* Back up source pointer! */
				result = targetExhausted;
				break;
			}
			if (ch <= UNI_MAX_BMP) { /* Target is a character <= 0xFFFF */
				/* UTF-16 surrogate values are illegal in UTF-32 */
				if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
					if (flags == strictConversion) {
						source -= (extraBytesToRead + 1); /* return to the illegal value itself */
						result = sourceIllegal;
						break;
					} else {
						*target++ = UNI_REPLACEMENT_CHAR;
					}
				} else {
					*target++ = (UTF16)ch; /* normal case */
				}
			} else if (ch > UNI_MAX_UTF16) {
				if (flags == strictConversion) {
					result = sourceIllegal;
					source -= (extraBytesToRead + 1); /* return to the start */
					break; /* Bail out; shouldn't continue */
				} else {
					*target++ = UNI_REPLACEMENT_CHAR;
				}
			} else {
				/* target is a character in range 0xFFFF - 0x10FFFF. */
				if (target + 1 >= targetEnd) {
					source -= (extraBytesToRead + 1); /* Back up source pointer! */
					result = targetExhausted;
					break;
				}
				ch -= halfBase;
				*target++ = (UTF16)((ch >> halfShift) + UNI_SUR_HIGH_START );
				*target++ = (UTF16)((ch & halfMask) + UNI_SUR_LOW_START );
			}
		}
		*sourceStart = source;
		*targetStart = target;
		return result;
	}

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

	ConversionResult ConvertUTF32toUTF8(const UTF32** sourceStart, const UTF32* sourceEnd,
	  UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags)
	{
		ConversionResult result = conversionOK;
		const UTF32* source = *sourceStart;
		UTF8* target = *targetStart;
		while (source < sourceEnd) {
			UTF32 ch;
			unsigned short bytesToWrite = 0;
			const UTF32 byteMask = 0xBF;
			const UTF32 byteMark = 0x80;
			ch = *source++;
			if (flags == strictConversion) {
				/* UTF-16 surrogate values are illegal in UTF-32 */
				if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
					--source; /* return to the illegal value itself */
					result = sourceIllegal;
					break;
				}
			}
			/*
			 * Figure out how many bytes the result will require. Turn any
			 * illegally large UTF32 things (> Plane 17) into replacement chars.
			 */
			if (ch < (UTF32)0x80) {
				bytesToWrite = 1;
			} else if (ch < (UTF32)0x800) {
				bytesToWrite = 2;
			} else if (ch < (UTF32)0x10000) {
				bytesToWrite = 3;
			} else if (ch <= UNI_MAX_LEGAL_UTF32) {
				bytesToWrite = 4;
			} else {
				bytesToWrite = 3;
				ch = UNI_REPLACEMENT_CHAR;
				result = sourceIllegal;
			}

			target += bytesToWrite;
			if (target > targetEnd) {
				--source; /* Back up source pointer! */
				target -= bytesToWrite;
				result = targetExhausted;
				break;
			}
			switch (bytesToWrite) { /* note: everything falls through. */
				case 4:
					*--target = (UTF8)((ch | byteMark) & byteMask);
					ch >>= 6;
					/* no break */
				case 3:
					*--target = (UTF8)((ch | byteMark) & byteMask);
					ch >>= 6;
					/* no break */
				case 2:
					*--target = (UTF8)((ch | byteMark) & byteMask);
					ch >>= 6;
					/* no break */
				case 1:
					*--target = (UTF8)(ch | firstByteMark[bytesToWrite]);
					/* no break */
			}
			target += bytesToWrite;
		}
		*sourceStart = source;
		*targetStart = target;
		return result;
	}

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

	ConversionResult ConvertUTF8toUTF32(const UTF8** sourceStart, const UTF8* sourceEnd,
	  UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags)
	{
		ConversionResult result = conversionOK;
		const UTF8* source = *sourceStart;
		UTF32* target = *targetStart;
		while (source < sourceEnd) {
			UTF32 ch = 0;
			unsigned short extraBytesToRead = trailingBytesForUTF8[*source];
			if (source + extraBytesToRead >= sourceEnd) {
				result = sourceExhausted;
				break;
			}
			/* Do this check whether lenient or strict */
			if (!isLegalUTF8(source, extraBytesToRead + 1)) {
				result = sourceIllegal;
				break;
			}
			/*
			 * The cases all fall through. See "Note A" below.
			 */
			switch (extraBytesToRead) {
				case 5:
					ch += *source++;
					ch <<= 6;
					/* no break */
				case 4:
					ch += *source++;
					ch <<= 6;
					/* no break */
				case 3:
					ch += *source++;
					ch <<= 6;
					/* no break */
				case 2:
					ch += *source++;
					ch <<= 6;
					/* no break */
				case 1:
					ch += *source++;
					ch <<= 6;
					/* no break */
				case 0:
					ch += *source++;
					/* no break */
			}
			ch -= offsetsFromUTF8[extraBytesToRead];

			if (target >= targetEnd) {
				source -= (extraBytesToRead + 1); /* Back up the source pointer! */
				result = targetExhausted;
				break;
			}
			if (ch <= UNI_MAX_LEGAL_UTF32) {
				/*
				 * UTF-16 surrogate values are illegal in UTF-32, and anything
				 * over Plane 17 (> 0x10FFFF) is illegal.
				 */
				if (ch >= UNI_SUR_HIGH_START && ch <= UNI_SUR_LOW_END) {
					if (flags == strictConversion) {
						source -= (extraBytesToRead + 1); /* return to the illegal value itself */
						result = sourceIllegal;
						break;
					} else {
						*target++ = UNI_REPLACEMENT_CHAR;
					}
				} else {
					*target++ = ch;
				}
			} else { /* i.e., ch > UNI_MAX_LEGAL_UTF32 */
				result = sourceIllegal;
				*target++ = UNI_REPLACEMENT_CHAR;
			}
		}
		*sourceStart = source;
		*targetStart = target;
		return result;
	}

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

	 Note A.
	 The fall-through switches in UTF-8 reading code save a
	 temp variable, some decrements & conditionals.  The switches
	 are equivalent to the following loop:
	 {
	 int tmpBytesToRead = extraBytesToRead+1;
	 do {
	 ch += *source++;
	 --tmpBytesToRead;
	 if (tmpBytesToRead) ch <<= 6;
	 } while (tmpBytesToRead > 0);
	 }
	 In UTF-8 writing code, the switches on "bytesToWrite" are
	 similarly unrolled loops.

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

//////////////
#ifdef __cplusplus

	transcode_to_utf16::transcode_to_utf16(const char *utf8_input)
			: _orig_length(int(strlen(utf8_input)) + 1), _converted(new UTF16[_orig_length + 1])
	// we don't ever expect the string to get longer going to the larger data
	// type, so the current length should be enough.
	{
		_result = conversionOK;
		if (_orig_length == 1) {
			// no length, so only provide a blank string.
			_converted[0] = 0;
			return;
		}
		memset((abyte *)_converted, 0, 2 * _orig_length);
		// we use these temporary pointers since the converter resets the source
		// and target pointers to the end of the conversion.  the same pattern
		// is used in the code below.
		const UTF8 *temp_in = (const UTF8 *)utf8_input;
		UTF16 *temp_out = _converted;
		_result = ConvertUTF8toUTF16(&temp_in, temp_in + _orig_length, &temp_out,
		    temp_out + _orig_length, lenientConversion);
	}

	transcode_to_utf16::transcode_to_utf16(const astring &utf8_input)
			: _orig_length(utf8_input.length() + 1), _converted(new UTF16[_orig_length])
	{
		_result = conversionOK;
		if (_orig_length == 1) {
			// no length, so only provide a blank string.
			_converted[0] = 0;
			return;
		}
		memset((abyte *)_converted, 0, 2 * _orig_length);
		const UTF8 *temp_in = (const UTF8 *)utf8_input.observe();
		UTF16 *temp_out = _converted;
		_result = ConvertUTF8toUTF16(&temp_in, temp_in + _orig_length, &temp_out,
		    temp_out + _orig_length, lenientConversion);
	}

	transcode_to_utf16::~transcode_to_utf16()
	{
		delete[] _converted;
		_converted = NULL_POINTER;
	}

	int transcode_to_utf16::length() const
	{
		return int(wcslen((wchar_t *)_converted));
	}

//////////////

	transcode_to_utf8::transcode_to_utf8(const UTF16 *utf16_input)
			: _orig_length(int(wcslen((const wchar_t *)utf16_input))),
			    _new_length(_orig_length * 2 + _orig_length / 2 + 1),
			    // this is just an estimate.  it may be appropriate most of the time.
			    // whatever doesn't fit will get truncated.
			    _converted(new UTF8[_new_length])
	{
		_result = conversionOK;
		if (_orig_length == 0) {
			// no length, so only provide a blank string.
			_converted[0] = 0;
			return;
		}
		memset(_converted, 0, _new_length);
		const UTF16 *temp_in = (const UTF16 *)utf16_input;
		UTF8 *temp_out = _converted;
		_result = ConvertUTF16toUTF8(&temp_in, temp_in + _orig_length, &temp_out,
		    temp_out + _new_length, lenientConversion);
	}

	transcode_to_utf8::transcode_to_utf8(const wchar_t *utf16_input)
			: _orig_length(int(wcslen(utf16_input))),
			    _new_length(_orig_length * 2 + _orig_length / 2 + 1),
			    // this is just an estimate.  it may be appropriate most of the time.
			    // whatever doesn't fit will get truncated.
			    _converted(new UTF8[_new_length > 0 ? _new_length : 1])
	{
		_result = conversionOK;
		if (_orig_length == 0) {
			// no length, so only provide a blank string.
			_converted[0] = 0;
			return;
		}
		memset(_converted, 0, _new_length);
		const UTF16 *temp_in = (const UTF16 *)utf16_input;
		UTF8 *temp_out = _converted;
		_result = ConvertUTF16toUTF8(&temp_in, temp_in + _orig_length, &temp_out,
		    temp_out + _new_length, lenientConversion);
	}

	transcode_to_utf8::~transcode_to_utf8()
	{
		delete[] _converted;
		_converted = NULL_POINTER;
	}

	int transcode_to_utf8::length() const
	{
		return int(strlen((char *)_converted));
	}

	transcode_to_utf8::operator astring() const
	{
		return astring((char *)_converted);
	}

//////////////

	null_transcoder::null_transcoder(const char *utf8_input, bool make_own_copy)
			: _make_own_copy(make_own_copy),
			    _converted(make_own_copy ? new UTF8[strlen(utf8_input) + 1] : (const UTF8 *)utf8_input)
	{
		if (_make_own_copy) {
			strcpy((char *)_converted, utf8_input);
		}
	}

	null_transcoder::null_transcoder(const astring &utf8_input, bool make_own_copy)
			: _make_own_copy(make_own_copy),
			    _converted(
			        make_own_copy ? new UTF8[utf8_input.length() + 1] : (const UTF8 *)utf8_input.s())
	{
		if (_make_own_copy) {
			strcpy((char *)_converted, utf8_input.s());
		}
	}

	int null_transcoder::length() const
	{
		return int(strlen((char *)_converted));
	}

#endif //_cplusplus
}  //namespace.