/*
 * Copyright © 1991-2015 Unicode, Inc. All rights reserved.
 * Distributed under the Terms of Use in 
 * http://www.unicode.org/copyright.html.
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of the Unicode data files and any associated documentation
 * (the "Data Files") or Unicode software and any associated documentation
 * (the "Software") to deal in the Data Files or Software
 * without restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, and/or sell copies of
 * the Data Files or Software, and to permit persons to whom the Data Files
 * or Software are furnished to do so, provided that
 * (a) this copyright and permission notice appear with all copies 
 * of the Data Files or Software,
 * (b) this copyright and permission notice appear in associated 
 * documentation, and
 * (c) there is clear notice in each modified Data File or in the Software
 * as well as in the documentation associated with the Data File(s) or
 * Software that the data or software has been modified.
 *
 * THE DATA FILES AND SOFTWARE ARE PROVIDED "AS IS", WITHOUT WARRANTY OF
 * ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
 * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT OF THIRD PARTY RIGHTS.
 * IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS INCLUDED IN THIS
 * NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT OR CONSEQUENTIAL
 * DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THE DATA FILES OR SOFTWARE.
 *
 * Except as contained in this notice, the name of a copyright holder
 * shall not be used in advertising or otherwise to promote the sale,
 * use or other dealings in these Data Files or Software without prior
 * written authorization of the copyright holder.
 */

#ifndef COMMON_CONVERT_UTF_H_
#define COMMON_CONVERT_UTF_H_

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

Conversions between UTF32, UTF-16, and UTF-8.  Header file.

Several funtions are included here, forming a complete set of
conversions between the three formats.  UTF-7 is not included
here, but is handled in a separate source file.

Each of these routines takes pointers to input buffers and output
buffers.  The input buffers are const.

Each routine converts the text between *sourceStart and sourceEnd,
putting the result into the buffer between *targetStart and
targetEnd. Note: the end pointers are *after* the last item: e.g.
*(sourceEnd - 1) is the last item.

The return result indicates whether the conversion was successful,
and if not, whether the problem was in the source or target buffers.
(Only the first encountered problem is indicated.)

After the conversion, *sourceStart and *targetStart are both
updated to point to the end of last text successfully converted in
the respective buffers.

Input parameters:
sourceStart - pointer to a pointer to the source buffer.
The contents of this are modified on return so that
it points at the next thing to be converted.
targetStart - similarly, pointer to pointer to the target buffer.
sourceEnd, targetEnd - respectively pointers to the ends of the
two buffers, for overflow checking only.

These conversion functions take a ConversionFlags argument. When this
flag is set to strict, both irregular sequences and isolated surrogates
will cause an error.  When the flag is set to lenient, both irregular
sequences and isolated surrogates are converted.

Whether the flag is strict or lenient, all illegal sequences will cause
an error return. This includes sequences such as: <F4 90 80 80>, <C0 80>,
or <A0> in UTF-8, and values above 0x10FFFF in UTF-32. Conformant code
must check for illegal sequences.

When the flag is set to lenient, characters over 0x10FFFF are converted
to the replacement character; otherwise (when the flag is set to strict)
they constitute an error.

Output parameters:
The value "sourceIllegal" is returned from some routines if the input
sequence is malformed.  When "sourceIllegal" is returned, the source
value will point to the illegal value that caused the problem. E.g.,
in UTF-8 when a sequence is malformed, it points to the start of the
malformed sequence.

Author: Mark E. Davis, 1994.
Rev History: Rick McGowan, fixes & updates May 2001.
Fixes & updates, Sept 2001.

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

/* ---------------------------------------------------------------------
The following 4 definitions are compiler-specific.
The C standard does not guarantee that wchar_t has at least
16 bits, so wchar_t is no less portable than unsigned short!
All should be unsigned values to avoid sign extension during
bit mask & shift operations.
------------------------------------------------------------------------ */

typedef unsigned long	UTF32;	/* at least 32 bits */
typedef unsigned short	UTF16;	/* at least 16 bits */
typedef unsigned char	UTF8;	/* typically 8 bits */
typedef unsigned char	Boolean; /* 0 or 1 */

/* Some fundamental constants */
#define UNI_REPLACEMENT_CHAR (UTF32)0x0000FFFD
#define UNI_MAX_BMP (UTF32)0x0000FFFF
#define UNI_MAX_UTF16 (UTF32)0x0010FFFF
#define UNI_MAX_UTF32 (UTF32)0x7FFFFFFF
#define UNI_MAX_LEGAL_UTF32 (UTF32)0x0010FFFF

typedef enum {
	conversionOK, 		/* conversion successful */
	sourceExhausted,	/* partial character in source, but hit end */
	targetExhausted,	/* insuff. room in target for conversion */
	sourceIllegal		/* source sequence is illegal/malformed */
} ConversionResult;

typedef enum {
	strictConversion = 0,
	lenientConversion
} ConversionFlags;

/* This is for C++ and does no harm in C */
#ifdef __cplusplus
extern "C" {
#endif

ConversionResult ConvertUTF8toUTF16 (const UTF8** sourceStart, const UTF8* sourceEnd,
                                     UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags);

ConversionResult ConvertUTF16toUTF8 (const UTF16** sourceStart, const UTF16* sourceEnd,
                                     UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags);

ConversionResult ConvertUTF8toUTF32 (const UTF8** sourceStart, const UTF8* sourceEnd,
                                     UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags);

ConversionResult ConvertUTF32toUTF8 (const UTF32** sourceStart, const UTF32* sourceEnd,
                                     UTF8** targetStart, UTF8* targetEnd, ConversionFlags flags);

ConversionResult ConvertUTF16toUTF32 (const UTF16** sourceStart, const UTF16* sourceEnd,
                                      UTF32** targetStart, UTF32* targetEnd, ConversionFlags flags);

ConversionResult ConvertUTF32toUTF16 (const UTF32** sourceStart, const UTF32* sourceEnd,
                                      UTF16** targetStart, UTF16* targetEnd, ConversionFlags flags);

Boolean isLegalUTF8Sequence(const UTF8 *source, const UTF8 *sourceEnd);

#ifdef __cplusplus
}
#endif

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

#endif  // COMMON_CONVERT_UTF_H_