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/*

 *

 * (C) Copyright IBM Corp. 1998-2005 - All Rights Reserved

 *

 * This file is a modification of the ICU file IndicReordering.h

 * by Jens Herden and Javier Sola for Khmer language

 *

 */

#ifndef __KHMERREORDERING_H

#define __KHMERREORDERING_H

#include "LETypes.h"

#include "OpenTypeTables.h"

class LEGlyphStorage;

// Vocabulary

// Base ->

//     A consonant or an independent vowel in its full (not

//     subscript) form. It is the center of the syllable, it can be

//     souranded by coeng (subscript) consonants, vowels, split

//     vowels, signs... but there is only one base in a syllable, it

//     has to be coded as the first character of the syllable.

// split vowel ->

//     vowel that has two parts placed separately (e.g. Before and

//     after the consonant).  Khmer language has five of them. Khmer

//     split vowels either have one part before the base and one after

//     the base or they have a part before the base and a part above

//     the base.  The first part of all Khmer split vowels is the same

//     character, identical to the glyph of Khmer dependent vowel SRA

//     EI

// coeng ->

//     modifier used in Khmer to construct coeng (subscript)

//     consonants differently than indian languages, the coeng

//     modifies the consonant that follows it, not the one preceding

//     it Each consonant has two forms, the base form and the

//     subscript form the base form is the normal one (using the

//     consonants code-point), the subscript form is displayed when

//     the combination coeng + consonant is encountered.

// Consonant of type 1 ->

//     A consonant which has subscript for that only occupies space

//     under a base consonant

// Consonant of type 2 ->

//     Its subscript form occupies space under and before the base

//     (only one, RO)

// Consonant of Type 3 ->

//     Its subscript form occupies space under and after the base

//     (KHO, CHHO, THHO, BA, YO, SA)

// Consonant shifter ->

//     Khmer has to series of consonants. The same dependent vowel has

//     different sounds if it is attached to a consonant of the first

//     series or a consonant of the second series Most consonants have

//     an equivalent in the other series, but some of theme exist only

//     in one series (for example SA). If we want to use the consonant

//     SA with a vowel sound that can only be done with a vowel sound

//     that corresponds to a vowel accompanying a consonant of the

//     other series, then we need to use a consonant shifter: TRIISAP

//     or MUSIKATOAN x17C9 y x17CA. TRIISAP changes a first series

//     consonant to second series sound and MUSIKATOAN a second series

//     consonant to have a first series vowel sound.  Consonant

//     shifter are both normally supercript marks, but, when they are

//     followed by a superscript, they change shape and take the form

//     of subscript dependent vowel SRA U.  If they are in the same

//     syllable as a coeng consonant, Unicode 3.0 says that they

//     should be typed before the coeng. Unicode 4.0 breaks the

//     standard and says that it should be placed after the coeng

//     consonant.

// Dependent vowel ->

//     In khmer dependent vowels can be placed above, below, before or

//     after the base Each vowel has its own position. Only one vowel

//     per syllable is allowed.

// Signs ->

//     Khmer has above signs and post signs. Only one above sign

//     and/or one post sign are Allowed in a syllable.

//

// This list must include all types of components that can be used

// inside a syllable

struct KhmerClassTable

{

    // order is important here! This order must be the same that is

    // found in each horizontal line in the statetable for Khmer (file

    // KhmerReordering.cpp).

    enum CharClassValues

    {

        CC_RESERVED             =  0,

        CC_CONSONANT            =  1, // consonant of type 1 or independent vowel

        CC_CONSONANT2           =  2, // Consonant of type 2

        CC_CONSONANT3           =  3, // Consonant of type 3

        CC_ZERO_WIDTH_NJ_MARK   =  4, // Zero Width non joiner character (0x200C)

        CC_CONSONANT_SHIFTER    =  5,

        CC_ROBAT                =  6, // Khmer special diacritic accent

                                      // -treated differently in state table

        CC_COENG                =  7, // Subscript consonant combining character

        CC_DEPENDENT_VOWEL      =  8,

        CC_SIGN_ABOVE           =  9,

        CC_SIGN_AFTER           = 10,

        CC_ZERO_WIDTH_J_MARK    = 11, // Zero width joiner character

        CC_COUNT                = 12  // This is the number of character classes

    };

    enum CharClassFlags

    {

        CF_CLASS_MASK    = 0x0000FFFF,

        CF_CONSONANT     = 0x01000000,  // flag to speed up comparing

        CF_SPLIT_VOWEL   = 0x02000000,  // flag for a split vowel -> the first part

                                        // is added in front of the syllable

        CF_DOTTED_CIRCLE = 0x04000000,  // add a dotted circle if a character with

                                        // this flag is the first in a syllable

        CF_COENG         = 0x08000000,  // flag to speed up comparing

        CF_SHIFTER       = 0x10000000,  // flag to speed up comparing

        CF_ABOVE_VOWEL   = 0x20000000,  // flag to speed up comparing

        // position flags

        CF_POS_BEFORE    = 0x00080000,

        CF_POS_BELOW     = 0x00040000,

        CF_POS_ABOVE     = 0x00020000,

        CF_POS_AFTER     = 0x00010000,

        CF_POS_MASK      = 0x000f0000

    };

    typedef le_uint32 CharClass;

    typedef le_int32 ScriptFlags;

    LEUnicode firstChar;   // for Khmer this will become x1780

    LEUnicode lastChar;    //  and this x17DF

    const CharClass *classTable;

    CharClass getCharClass(LEUnicode ch) const;

    static const KhmerClassTable *getKhmerClassTable();

};

class KhmerReordering {

public:

    static le_int32 reorder(const LEUnicode *theChars, le_int32 charCount,

        le_int32 scriptCode, LEUnicode *outChars, LEGlyphStorage &glyphStorage);

    static const FeatureMap *getFeatureMap(le_int32 &count);

private:

    // do not instantiate

    KhmerReordering();

    static le_int32 findSyllable(const KhmerClassTable *classTable,

        const LEUnicode *chars, le_int32 prev, le_int32 charCount);

};

#endif