/***************************************************************************

*

*   Copyright (C) 1998-2003, International Business Machines

*   Corporation and others.  All Rights Reserved.

*

************************************************************************/

#include "LETypes.h"

#include "LESwaps.h"

#include "sfnt.h"

#include "cmaps.h"

#define SWAPU16(code) ((LEUnicode16) SWAPW(code))

#define SWAPU32(code) ((LEUnicode32) SWAPL(code))

//

// Finds the high bit by binary searching

// through the bits in value.

//

le_int8 highBit(le_uint32 value)

{

    le_uint8 bit = 0;

    if (value >= 1 << 16) {

        value >>= 16;

        bit += 16;

    }

    if (value >= 1 << 8) {

        value >>= 8;

        bit += 8;

    }

    if (value >= 1 << 4) {

        value >>= 4;

        bit += 4;

    }

    if (value >= 1 << 2) {

        value >>= 2;

        bit += 2;

    }

    if (value >= 1 << 1) {

        value >>= 1;

        bit += 1;

    }

    return bit;

}

CMAPMapper *CMAPMapper::createUnicodeMapper(const CMAPTable *cmap)

{

    le_uint16 i;

    le_uint16 nSubtables = SWAPW(cmap->numberSubtables);

    const CMAPEncodingSubtable *subtable = NULL;

    le_uint32 offset1 = 0, offset10 = 0;

    for (i = 0; i < nSubtables; i += 1) {

        const CMAPEncodingSubtableHeader *esh = &cmap->encodingSubtableHeaders[i];

        if (SWAPW(esh->platformID) == 3) {

            switch (SWAPW(esh->platformSpecificID)) {

            case 1:

                offset1 = SWAPL(esh->encodingOffset);

                break;

            case 10:

                offset10 = SWAPL(esh->encodingOffset);

                break;

            }

        }

    }

    if (offset10 != 0)

    {

        subtable = (const CMAPEncodingSubtable *) ((const char *) cmap + offset10);

    } else if (offset1 != 0) {

        subtable = (const CMAPEncodingSubtable *) ((const char *) cmap + offset1);

    } else {

        return NULL;

    }

    switch (SWAPW(subtable->format)) {

    case 4:

        return new CMAPFormat4Mapper(cmap, (const CMAPFormat4Encoding *) subtable);

    case 12:

    {

        const CMAPFormat12Encoding *encoding = (const CMAPFormat12Encoding *) subtable;

        return new CMAPGroupMapper(cmap, encoding->groups, SWAPL(encoding->nGroups));

    }

    default:

        break;

    }

    return NULL;

}

CMAPFormat4Mapper::CMAPFormat4Mapper(const CMAPTable *cmap, const CMAPFormat4Encoding *header)

    : CMAPMapper(cmap)

{

    le_uint16 segCount = SWAPW(header->segCountX2) / 2;

    fEntrySelector = SWAPW(header->entrySelector);

    fRangeShift = SWAPW(header->rangeShift) / 2;

    fEndCodes = &header->endCodes[0];

    fStartCodes = &header->endCodes[segCount + 1]; // + 1 for reservedPad...

    fIdDelta = &fStartCodes[segCount];

    fIdRangeOffset = &fIdDelta[segCount];

}

LEGlyphID CMAPFormat4Mapper::unicodeToGlyph(LEUnicode32 unicode32) const

{

    if (unicode32 >= 0x10000) {

        return 0;

    }

    LEUnicode16 unicode = (LEUnicode16) unicode32;

    le_uint16 index = 0;

    le_uint16 probe = 1 << fEntrySelector;

    TTGlyphID result = 0;

    if (SWAPU16(fStartCodes[fRangeShift]) <= unicode) {

        index = fRangeShift;

    }

    while (probe > (1 << 0)) {

        probe >>= 1;

        if (SWAPU16(fStartCodes[index + probe]) <= unicode) {

            index += probe;

        }

    }

    if (unicode >= SWAPU16(fStartCodes[index]) && unicode <= SWAPU16(fEndCodes[index])) {

        if (fIdRangeOffset[index] == 0) {

            result = (TTGlyphID) unicode;

        } else {

            le_uint16 offset = unicode - SWAPU16(fStartCodes[index]);

            le_uint16 rangeOffset = SWAPW(fIdRangeOffset[index]);

            le_uint16 *glyphIndexTable = (le_uint16 *) ((char *) &fIdRangeOffset[index] + rangeOffset);

            result = SWAPW(glyphIndexTable[offset]);

        }

        result += SWAPW(fIdDelta[index]);

    } else {

        result = 0;

    }

    return LE_SET_GLYPH(0, result);

}

CMAPFormat4Mapper::~CMAPFormat4Mapper()

{

    // parent destructor does it all

}

CMAPGroupMapper::CMAPGroupMapper(const CMAPTable *cmap, const CMAPGroup *groups, le_uint32 nGroups)

    : CMAPMapper(cmap), fGroups(groups)

{

    le_uint8 bit = highBit(nGroups);

    fPower = 1 << bit;

    fRangeOffset = nGroups - fPower;

}

LEGlyphID CMAPGroupMapper::unicodeToGlyph(LEUnicode32 unicode32) const

{

    le_int32 probe = fPower;

    le_int32 range = 0;

    if (SWAPU32(fGroups[fRangeOffset].startCharCode) <= unicode32) {

        range = fRangeOffset;

    }

    while (probe > (1 << 0)) {

        probe >>= 1;

        if (SWAPU32(fGroups[range + probe].startCharCode) <= unicode32) {

            range += probe;

        }

    }

    if (SWAPU32(fGroups[range].startCharCode) <= unicode32 && SWAPU32(fGroups[range].endCharCode) >= unicode32) {

        return (LEGlyphID) (SWAPU32(fGroups[range].startGlyphCode) + unicode32 - SWAPU32(fGroups[range].startCharCode));

    }

    return 0;

}

CMAPGroupMapper::~CMAPGroupMapper()

{

    // parent destructor does it all

}