/*

 *

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

 *

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

 * by Jens Herden and Javier Sola for Khmer language 

 *

 */

#include "LETypes.h"

#include "KhmerReordering.h"

#include "LEGlyphStorage.h"

U_NAMESPACE_BEGIN

// Characters that get refered to by name...

enum

{

    C_SIGN_ZWNJ     = 0x200C,

    C_SIGN_ZWJ      = 0x200D,

    C_DOTTED_CIRCLE = 0x25CC,

    C_RO            = 0x179A,

    C_VOWEL_AA      = 0x17B6,

    C_SIGN_NIKAHIT  = 0x17C6,

    C_VOWEL_E       = 0x17C1,

    C_COENG         = 0x17D2

};

enum

{

    // simple classes, they are used in the statetable (in this file) to control the length of a syllable

    // they are also used to know where a character should be placed (location in reference to the base character)

    // and also to know if a character, when independtly displayed, should be displayed with a dotted-circle to

    // indicate error in syllable construction 

    _xx = KhmerClassTable::CC_RESERVED,

    _sa = KhmerClassTable::CC_SIGN_ABOVE | KhmerClassTable::CF_DOTTED_CIRCLE | KhmerClassTable::CF_POS_ABOVE,

    _sp = KhmerClassTable::CC_SIGN_AFTER | KhmerClassTable::CF_DOTTED_CIRCLE| KhmerClassTable::CF_POS_AFTER,

    _c1 = KhmerClassTable::CC_CONSONANT | KhmerClassTable::CF_CONSONANT,

    _c2 = KhmerClassTable::CC_CONSONANT2 | KhmerClassTable::CF_CONSONANT,

    _c3 = KhmerClassTable::CC_CONSONANT3 | KhmerClassTable::CF_CONSONANT,

    _rb = KhmerClassTable::CC_ROBAT | KhmerClassTable::CF_POS_ABOVE | KhmerClassTable::CF_DOTTED_CIRCLE,

    _cs = KhmerClassTable::CC_CONSONANT_SHIFTER | KhmerClassTable::CF_DOTTED_CIRCLE | KhmerClassTable::CF_SHIFTER,

    _dl = KhmerClassTable::CC_DEPENDENT_VOWEL | KhmerClassTable::CF_POS_BEFORE | KhmerClassTable::CF_DOTTED_CIRCLE, 

    _db = KhmerClassTable::CC_DEPENDENT_VOWEL | KhmerClassTable::CF_POS_BELOW | KhmerClassTable::CF_DOTTED_CIRCLE,

    _da = KhmerClassTable::CC_DEPENDENT_VOWEL | KhmerClassTable::CF_POS_ABOVE | KhmerClassTable::CF_DOTTED_CIRCLE | KhmerClassTable::CF_ABOVE_VOWEL,

    _dr = KhmerClassTable::CC_DEPENDENT_VOWEL | KhmerClassTable::CF_POS_AFTER | KhmerClassTable::CF_DOTTED_CIRCLE,

    _co = KhmerClassTable::CC_COENG | KhmerClassTable::CF_COENG | KhmerClassTable::CF_DOTTED_CIRCLE,

    // split vowel

    _va = _da | KhmerClassTable::CF_SPLIT_VOWEL,

    _vr = _dr | KhmerClassTable::CF_SPLIT_VOWEL

};

// Character class tables 

// _xx character does not combine into syllable, such as numbers, puntuation marks, non-Khmer signs... 

// _sa Sign placed above the base

// _sp Sign placed after the base

// _c1 Consonant of type 1 or independent vowel (independent vowels behave as type 1 consonants)

// _c2 Consonant of type 2 (only RO)

// _c3 Consonant of type 3 

// _rb Khmer sign robat u17CC. combining mark for subscript consonants

// _cd Consonant-shifter

// _dl Dependent vowel placed before the base (left of the base)

// _db Dependent vowel placed below the base 

// _da Dependent vowel placed above the base

// _dr Dependent vowel placed behind the base (right of the base)    

// _co Khmer combining mark COENG u17D2, combines with the consonant or independent vowel following 

//     it to create a subscript consonant or independent vowel   

// _va Khmer split vowel in wich the first part is before the base and the second one above the base

// _vr Khmer split vowel in wich the first part is before the base and the second one behind (right of) the base

static const KhmerClassTable::CharClass khmerCharClasses[] =

{

    _c1, _c1, _c1, _c3, _c1, _c1, _c1, _c1, _c3, _c1, _c1, _c1, _c1, _c3, _c1, _c1, // 1780 - 178F

    _c1, _c1, _c1, _c1, _c3, _c1, _c1, _c1, _c1, _c3, _c2, _c1, _c1, _c1, _c3, _c3, // 1790 - 179F

    _c1, _c3, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, _c1, // 17A0 - 17AF

    _c1, _c1, _c1, _c1, _dr, _dr, _dr, _da, _da, _da, _da, _db, _db, _db, _va, _vr, // 17B0 - 17BF

    _vr, _dl, _dl, _dl, _vr, _vr, _sa, _sp, _sp, _cs, _cs, _sa, _rb, _sa, _sa, _sa, // 17C0 - 17CF

    _sa, _sa, _co, _sa, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _xx, _sa, _xx, _xx, // 17D0 - 17DF

};                                                                                  

//

// Khmer Class Tables

//                   

//

// The range of characters defined in the above table is defined here. FOr Khmer 1780 to 17DF

// Even if the Khmer range is bigger, all other characters are not combinable, and therefore treated

// as _xx

static const KhmerClassTable khmerClassTable = {0x1780, 0x17df, khmerCharClasses};

// Below we define how a character in the input string is either in the khmerCharClasses table

// (in which case we get its type back), a ZWJ or ZWNJ (two characters that may appear 

// within the syllable, but are not in the table) we also get their type back, or an unknown object

// in which case we get _xx (CC_RESERVED) back

KhmerClassTable::CharClass KhmerClassTable::getCharClass(LEUnicode ch) const

{

    if (ch == C_SIGN_ZWJ) {

        return CC_ZERO_WIDTH_J_MARK;

    }

    if (ch == C_SIGN_ZWNJ) {

        return CC_ZERO_WIDTH_NJ_MARK;

    }

    if (ch < firstChar || ch > lastChar) {

        return CC_RESERVED;

    }

    return classTable[ch - firstChar];

}

const KhmerClassTable *KhmerClassTable::getKhmerClassTable()

{

    return &khmerClassTable;

}

class ReorderingOutput : public UMemory {

private:

    le_int32 fOutIndex;

    LEUnicode *fOutChars;

    LEGlyphStorage &fGlyphStorage;

public:

    ReorderingOutput(LEUnicode *outChars, LEGlyphStorage &glyphStorage)

        : fOutIndex(0), fOutChars(outChars), fGlyphStorage(glyphStorage)

    {

        // nothing else to do...

    }

    ~ReorderingOutput()

    {

        // nothing to do here...

    }

    void writeChar(LEUnicode ch, le_uint32 charIndex, const LETag *charTags)

    {

        LEErrorCode success = LE_NO_ERROR;

        fOutChars[fOutIndex] = ch;

        fGlyphStorage.setCharIndex(fOutIndex, charIndex, success);

        fGlyphStorage.setAuxData(fOutIndex, (void *) charTags, success);

        fOutIndex += 1;

    }

    le_int32 getOutputIndex()

    {

        return fOutIndex;

    }

};

static const LETag emptyTag       = 0x00000000; // ''

//TODO remove unused flags

//static const LETag nuktFeatureTag = LE_NUKT_FEATURE_TAG;

//static const LETag akhnFeatureTag = LE_AKHN_FEATURE_TAG;

//static const LETag rphfFeatureTag = LE_RPHF_FEATURE_TAG;

static const LETag blwfFeatureTag = LE_BLWF_FEATURE_TAG;

//static const LETag halfFeatureTag = LE_HALF_FEATURE_TAG;

static const LETag pstfFeatureTag = LE_PSTF_FEATURE_TAG;

//static const LETag vatuFeatureTag = LE_VATU_FEATURE_TAG;

static const LETag presFeatureTag = LE_PRES_FEATURE_TAG;

static const LETag blwsFeatureTag = LE_BLWS_FEATURE_TAG;

static const LETag abvsFeatureTag = LE_ABVS_FEATURE_TAG;

static const LETag pstsFeatureTag = LE_PSTS_FEATURE_TAG;

//static const LETag halnFeatureTag = LE_HALN_FEATURE_TAG;

static const LETag blwmFeatureTag = LE_BLWM_FEATURE_TAG;

static const LETag abvmFeatureTag = LE_ABVM_FEATURE_TAG;

static const LETag distFeatureTag = LE_DIST_FEATURE_TAG;

static const LETag prefFeatureTag = LE_PREF_FEATURE_TAG;

static const LETag abvfFeatureTag = LE_ABVF_FEATURE_TAG;

static const LETag cligFeatureTag = LE_CLIG_FEATURE_TAG;

static const LETag mkmkFeatureTag = LE_MKMK_FEATURE_TAG;

// These are in the order in which the features need to be applied

// for correct processing

static const LETag featureOrder[] =

{

    // Shaping features

    prefFeatureTag, blwfFeatureTag, abvfFeatureTag, pstfFeatureTag, 

    presFeatureTag, blwsFeatureTag, abvsFeatureTag, pstsFeatureTag,

    cligFeatureTag, 

    // Positioning features

    distFeatureTag, blwmFeatureTag, abvmFeatureTag, mkmkFeatureTag,

    emptyTag

};

static const LETag tagPref[] = 

{

    prefFeatureTag, presFeatureTag, 

    cligFeatureTag, 

    // Positioning features

    distFeatureTag, 

    emptyTag

};

static const LETag tagAbvf[] = 

{

    abvfFeatureTag, abvsFeatureTag, 

    cligFeatureTag, 

    // Positioning features

    distFeatureTag, abvmFeatureTag, mkmkFeatureTag,

    emptyTag

};

static const LETag tagPstf[] = 

{

    blwfFeatureTag, blwsFeatureTag, 

    prefFeatureTag, presFeatureTag, 

    pstfFeatureTag, pstsFeatureTag, 

    cligFeatureTag, 

    // Positioning features

    distFeatureTag, blwmFeatureTag, 

    emptyTag

};

static const LETag tagBlwf[] = 

{

    blwfFeatureTag, blwsFeatureTag, 

    cligFeatureTag, 

    // Positioning features

    distFeatureTag, blwmFeatureTag, mkmkFeatureTag,

    emptyTag

};

// TODO do we need all of them?

static const LETag tagDefault[] = 

{

    // Shaping feature

    prefFeatureTag, blwfFeatureTag, /*abvfFeatureTag,*/ /*pstfFeatureTag, */

    presFeatureTag, blwsFeatureTag, /*abvsFeatureTag,*/ /*pstsFeatureTag,*/

    cligFeatureTag, 

    // Positioning features

    distFeatureTag, abvmFeatureTag, blwmFeatureTag, mkmkFeatureTag,

    emptyTag

};

// The stateTable is used to calculate the end (the length) of a well

// formed Khmer Syllable. 

//

// Each horizontal line is ordered exactly the same way as the values in KhmerClassTable

// CharClassValues in KhmerReordering.h This coincidence of values allows the

// follow up of the table.

//

// Each line corresponds to a state, which does not necessarily need to be a type

// of component... for example, state 2 is a base, with is always a first character

// in the syllable, but the state could be produced a consonant of any type when

// it is the first character that is analysed (in ground state).

//

// Differentiating 3 types of consonants is necessary in order to 

// forbid the use of certain combinations, such as having a second

// coeng after a coeng RO, 

// The inexistent possibility of having a type 3 after another type 3 is permitted,

// eliminating it would very much complicate the table, and it does not create typing

// problems, as the case above.

//

// The table is quite complex, in order to limit the number of coeng consonants

// to 2 (by means of the table).

//

// There a peculiarity, as far as Unicode is concerned:

// - The consonant-shifter is considered in two possible different 

//   locations, the one considered in Unicode 3.0 and the one considered in

//   Unicode 4.0. (there is a backwards compatibility problem in this standard).

// xx    independent character, such as a number, punctuation sign or non-khmer char

//

// c1    Khmer consonant of type 1 or an independent vowel

//       that is, a letter in which the subscript for is only under the

//       base, not taking any space to the right or to the left

//

// c2    Khmer consonant of type 2, the coeng form takes space under

//       and to the left of the base (only RO is of this type)

//

// c3    Khmer consonant of type 3. Its subscript form takes space under

//       and to the right of the base. 

//

// cs    Khmer consonant shifter         

//

// rb    Khmer robat

//

// co    coeng character (u17D2)

//

// dv    dependent vowel (including split vowels, they are treated in the same way).

//       even if dv is not defined above, the component that is really tested for is

//       KhmerClassTable::CC_DEPENDENT_VOWEL, which is common to all dependent vowels

//

// zwj   Zero Width joiner

//

// zwnj  Zero width non joiner  

//

// sa    above sign

//

// sp    post sign    

// 

// there are lines with equal content but for an easier understanding 

// (and maybe change in the future) we did not join them

//

static const le_int8 khmerStateTable[][KhmerClassTable::CC_COUNT] =

{

//   xx  c1  c2  c3 zwnj cs  rb  co  dv  sa  sp zwj  

    { 1,  2,  2,  2,  1,  1,  1,  6,  1,  1,  1,  2}, //  0 - ground state

    {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1}, //  1 - exit state (or sign to the right of the syllable)

    {-1, -1, -1, -1,  3,  4,  5,  6, 16, 17,  1, -1}, //  2 - Base consonant    

    {-1, -1, -1, -1, -1,  4, -1, -1, 16, -1, -1, -1}, //  3 - First ZWNJ before a register shifter

                                                      //      It can only be followed by a shifter or a vowel

    {-1, -1, -1, -1, 15, -1, -1,  6, 16, 17,  1, 14}, //  4 - First register shifter             

    {-1, -1, -1, -1, -1, -1, -1, -1, 20, -1,  1, -1}, //  5 - Robat

    {-1,  7,  8,  9, -1, -1, -1, -1, -1, -1, -1, -1}, //  6 - First Coeng

    {-1, -1, -1, -1, 12, 13, -1, 10, 16, 17,  1, 14}, //  7 - First consonant of type 1 after coeng 

    {-1, -1, -1, -1, 12, 13, -1, -1, 16, 17,  1, 14}, //  8 - First consonant of type 2 after coeng

    {-1, -1, -1, -1, 12, 13, -1, 10, 16, 17,  1, 14}, //  9 - First consonant or type 3 after ceong

    {-1, 11, 11, 11, -1, -1, -1, -1, -1, -1, -1, -1}, // 10 - Second Coeng (no register shifter before)

    {-1, -1, -1, -1, 15, -1, -1, -1, 16, 17,  1, 14}, // 11 - Second coeng consonant (or ind. vowel) no register shifter before 

    {-1, -1,  1, -1, -1, 13, -1, -1, 16, -1, -1, -1}, // 12 - Second ZWNJ before a register shifter

    {-1, -1, -1, -1, 15, -1, -1, -1, 16, 17,  1, 14}, // 13 - Second register shifter 

    {-1, -1, -1, -1, -1, -1, -1, -1, 16, -1, -1, -1}, // 14 - ZWJ before vowel    

    {-1, -1, -1, -1, -1, -1, -1, -1, 16, -1, -1, -1}, // 15 - ZWNJ before vowel

    {-1, -1, -1, -1, -1, -1, -1, -1, -1, 17,  1, 18}, // 16 - dependent vowel 

    {-1, -1,  1, -1, -1, -1, -1, -1, -1, -1,  1, 18}, // 17 - sign above

    {-1, -1, -1, -1, -1, -1, -1, 19, -1, -1, -1, -1}, // 18 - ZWJ after vowel    

    {-1,  1, -1,  1, -1, -1, -1, -1, -1, -1, -1, -1}, // 19 - Third coeng 

    {-1, -1, -1, -1, -1, -1, -1, -1, -1, -1,  1, -1}, // 20 - dependent vowel after a Robat

};         

const LETag *KhmerReordering::getFeatureOrder()

{

    return featureOrder;

}

// Given an input string of characters and a location in which to start looking

// calculate, using the state table, which one is the last character of the syllable

// that starts in the starting position.

le_int32 KhmerReordering::findSyllable(const KhmerClassTable *classTable, const LEUnicode *chars, le_int32 prev, le_int32 charCount)

{

    le_int32 cursor = prev;

    le_int8 state = 0;

    while (cursor < charCount) {

        KhmerClassTable::CharClass charClass = (classTable->getCharClass(chars[cursor]) & KhmerClassTable::CF_CLASS_MASK);

        state = khmerStateTable[state][charClass];

        if (state < 0) {

            break;

        }

        cursor += 1;

    }

    return cursor;

}

// This is the real reordering function as applied to the Khmer language

le_int32 KhmerReordering::reorder(const LEUnicode *chars, le_int32 charCount, le_int32 /*scriptCode*/,

                                  LEUnicode *outChars, LEGlyphStorage &glyphStorage)

{

    const KhmerClassTable *classTable = KhmerClassTable::getKhmerClassTable();

    ReorderingOutput output(outChars, glyphStorage);

    KhmerClassTable::CharClass charClass;

    le_int32 i, prev = 0, coengRo;

    // This loop only exits when we reach the end of a run, which may contain 

    // several syllables.

    while (prev < charCount) {

        le_int32 syllable = findSyllable(classTable, chars, prev, charCount);

        // write a pre vowel or the pre part of a split vowel first

        // and look out for coeng + ro. RO is the only vowel of type 2, and

        // therefore the only one that requires saving space before the base.

        coengRo = -1;  // There is no Coeng Ro, if found this value will change

        for (i = prev; i < syllable; i += 1) {

            charClass = classTable->getCharClass(chars[i]);

            // if a split vowel, write the pre part. In Khmer the pre part

            // is the same for all split vowels, same glyph as pre vowel C_VOWEL_E

            if (charClass & KhmerClassTable::CF_SPLIT_VOWEL) {

                output.writeChar(C_VOWEL_E, i, &tagPref[0]);

                break; // there can be only one vowel

            }

            // if a vowel with pos before write it out

            if (charClass & KhmerClassTable::CF_POS_BEFORE) {

                output.writeChar(chars[i], i, &tagPref[0]);

                break; // there can be only one vowel 

            }

            // look for coeng + ro and remember position

            // works because coeng + ro is always in front of a vowel (if there is a vowel) 

            // and because CC_CONSONANT2 is enough to identify it, as it is the only consonant

            // with this flag

            if ( (charClass & KhmerClassTable::CF_COENG) && (i + 1 < syllable) &&

                 ( (classTable->getCharClass(chars[i + 1]) & KhmerClassTable::CF_CLASS_MASK) == KhmerClassTable::CC_CONSONANT2) )

            {

                    coengRo = i;

            }

        }

        // write coeng + ro if found

        if (coengRo > -1) {

            output.writeChar(C_COENG, coengRo, &tagPref[0]);

            output.writeChar(C_RO, coengRo + 1, &tagPref[0]);

        }

        // shall we add a dotted circle?

        // If in the position in which the base should be (first char in the string) there is

        // a character that has the Dotted circle flag (a character that cannot be a base)

        // then write a dotted circle

        if (classTable->getCharClass(chars[prev]) & KhmerClassTable::CF_DOTTED_CIRCLE) {

            output.writeChar(C_DOTTED_CIRCLE, prev, &tagDefault[0]);        

        }        

        // copy what is left to the output, skipping before vowels and coeng Ro if they are present

        for (i = prev; i < syllable; i += 1) {

            charClass = classTable->getCharClass(chars[i]);

            // skip a before vowel, it was already processed

            if (charClass & KhmerClassTable::CF_POS_BEFORE) {

                continue;

            }

            // skip coeng + ro, it was already processed

            if (i == coengRo) {

                i += 1;

                continue;

            }

            switch (charClass & KhmerClassTable::CF_POS_MASK) {

                case KhmerClassTable::CF_POS_ABOVE :

                    output.writeChar(chars[i], i, &tagAbvf[0]);

                    break;

                case KhmerClassTable::CF_POS_AFTER :

                    output.writeChar(chars[i], i, &tagPstf[0]);

                    break;

                case KhmerClassTable::CF_POS_BELOW :

                    output.writeChar(chars[i], i, &tagBlwf[0]);

                    break;

                default:

                    // assign the correct flags to a coeng consonant

                    // Consonants of type 3 are taged as Post forms and those type 1 as below forms

                    if ( (charClass & KhmerClassTable::CF_COENG) && i + 1 < syllable ) {

                        if ( (classTable->getCharClass(chars[i + 1]) & KhmerClassTable::CF_CLASS_MASK) 

                              == KhmerClassTable::CC_CONSONANT3) {

                            output.writeChar(chars[i], i, &tagPstf[0]);

                            i += 1;

                            output.writeChar(chars[i], i, &tagPstf[0]);

                        }

                        else {

                            output.writeChar(chars[i], i, &tagBlwf[0]);

                            i += 1;

                            output.writeChar(chars[i], i, &tagBlwf[0]);

                        }

                        break;

                    }

                    // if a shifter is followed by an above vowel change the shifter to below form,

                    // an above vowel can have two possible positions i + 1 or i + 3 

                    // (position i+1 corresponds to unicode 3, position i+3 to Unicode 4)

                    // and there is an extra rule for C_VOWEL_AA + C_SIGN_NIKAHIT also for two

                    // different positions, right after the shifter or after a vowel (Unicode 4)

                    if ( (charClass & KhmerClassTable::CF_SHIFTER) && (i + 1 < syllable) ) {

                        if ((classTable->getCharClass(chars[i + 1]) & KhmerClassTable::CF_ABOVE_VOWEL)

                            || (i + 2 < syllable

                                && ( (classTable->getCharClass(chars[i + 1]) & KhmerClassTable::CF_CLASS_MASK) == C_VOWEL_AA)

                                && ( (classTable->getCharClass(chars[i + 2]) & KhmerClassTable::CF_CLASS_MASK) == C_SIGN_NIKAHIT))

                            || (i + 3 < syllable && (classTable->getCharClass(chars[i + 3]) & KhmerClassTable::CF_ABOVE_VOWEL))

                            || (i + 4 < syllable

                                && ( (classTable->getCharClass(chars[i + 3]) & KhmerClassTable::CF_CLASS_MASK) == C_VOWEL_AA)

                                && ( (classTable->getCharClass(chars[i + 4]) & KhmerClassTable::CF_CLASS_MASK) == C_SIGN_NIKAHIT) ) ) 

                        {

                            output.writeChar(chars[i], i, &tagBlwf[0]);

                            break;

                        }

                    }

                    // default - any other characters

                    output.writeChar(chars[i], i, &tagDefault[0]);

                    break;

            } // switch

        } // for

        prev = syllable; // move the pointer to the start of next syllable

    }

    return output.getOutputIndex();

}

U_NAMESPACE_END