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

*

*   Copyright (C) 1998-2002, International Business Machines

*   Corporation and others.  All Rights Reserved.

*

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

#include <stdio.h>

#include "LETypes.h"

#include "FontObject.h"

#include "LESwaps.h"

FontObject::FontObject(char *fileName)

  : directory(NULL), numTables(0), searchRange(0),entrySelector(0),

    cmapTable(NULL), cmSegCount(0), cmSearchRange(0), cmEntrySelector(0),

    cmEndCodes(NULL), cmStartCodes(NULL), cmIdDelta(0), cmIdRangeOffset(0),

    headTable(NULL), hmtxTable(NULL), numGlyphs(0), numOfLongHorMetrics(0), file(NULL)

{

    file = fopen(fileName, "rb");

    if (file == NULL) {

        printf("?? Couldn't open %s", fileName);

        return;

    }

    SFNTDirectory tempDir;

    fread(&tempDir, sizeof tempDir, 1, file);

    numTables       = SWAPW(tempDir.numTables);

    searchRange     = SWAPW(tempDir.searchRange) >> 4;

    entrySelector   = SWAPW(tempDir.entrySelector);

    rangeShift      = SWAPW(tempDir.rangeShift) >> 4;

    int dirSize = sizeof tempDir + ((numTables - ANY_NUMBER) * sizeof(DirectoryEntry));

    directory = (SFNTDirectory *) new char[dirSize];

    fseek(file, 0L, SEEK_SET);

    fread(directory, sizeof(char), dirSize, file);

    initUnicodeCMAP();

}

FontObject::~FontObject()

{

    fclose(file);

    delete[] directory;

    delete[] cmapTable;

    delete[] headTable;

    delete[] hmtxTable;

}

void FontObject::deleteTable(void *table)

{

    delete[] (char *) table;

}

DirectoryEntry *FontObject::findTable(LETag tag)

{

    le_uint16 table = 0;

    le_uint16 probe = 1 << entrySelector;

    if (SWAPL(directory->tableDirectory[rangeShift].tag) <= tag) {

        table = rangeShift;

    }

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

        probe >>= 1;

        if (SWAPL(directory->tableDirectory[table + probe].tag) <= tag) {

            table += probe;

        }

    }

    if (SWAPL(directory->tableDirectory[table].tag) == tag) {

        return &directory->tableDirectory[table];

    }

    return NULL;

}

void *FontObject::readTable(LETag tag, le_uint32 *length)

{

    DirectoryEntry *entry = findTable(tag);

    if (entry == NULL) {

        *length = 0;

        return NULL;

    }

    *length = SWAPL(entry->length);

    void *table = new char[*length];

    fseek(file, SWAPL(entry->offset), SEEK_SET);

    fread(table, sizeof(char), *length, file);

    return table;

}

CMAPEncodingSubtable *FontObject::findCMAP(le_uint16 platformID, le_uint16 platformSpecificID)

{

    LETag cmapTag = 0x636D6170; // 'cmap'

    if (cmapTable == NULL) {

        le_uint32 length;

        cmapTable = (CMAPTable *) readTable(cmapTag, &length);

    }

    if (cmapTable != NULL) {

        le_uint16 i;

        le_uint16 nSubtables = SWAPW(cmapTable->numberSubtables);

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

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

            if (SWAPW(esh->platformID) == platformID &&

                SWAPW(esh->platformSpecificID) == platformSpecificID) {

                return (CMAPEncodingSubtable *) ((char *) cmapTable + SWAPL(esh->encodingOffset));

            }

        }

    }

    return NULL;

}

void FontObject::initUnicodeCMAP()

{

    CMAPEncodingSubtable *encodingSubtable = findCMAP(3, 1);

    if (encodingSubtable == 0 ||

        SWAPW(encodingSubtable->format) != 4) {

        printf("Can't find unicode 'cmap'");

        return;

    }

    CMAPFormat4Encoding *header = (CMAPFormat4Encoding *) encodingSubtable;

    cmSegCount = SWAPW(header->segCountX2) / 2;

    cmSearchRange = SWAPW(header->searchRange);

    cmEntrySelector = SWAPW(header->entrySelector);

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

    cmEndCodes = &header->endCodes[0];

    cmStartCodes = &header->endCodes[cmSegCount + 1]; // + 1 for reservedPad...

    cmIdDelta = &cmStartCodes[cmSegCount];

    cmIdRangeOffset = &cmIdDelta[cmSegCount];

}

LEGlyphID FontObject::unicodeToGlyph(LEUnicode32 unicode32)

{

    if (unicode32 >= 0x10000) {

        return 0;

    }

    LEUnicode16 unicode = (LEUnicode16) unicode32;

    le_uint16 index = 0;

    le_uint16 probe = 1 << cmEntrySelector;

    LEGlyphID result = 0;

    if (SWAPW(cmStartCodes[cmRangeShift]) <= unicode) {

        index = cmRangeShift;

    }

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

        probe >>= 1;

        if (SWAPW(cmStartCodes[index + probe]) <= unicode) {

            index += probe;

        }

    }

    if (unicode >= SWAPW(cmStartCodes[index]) && unicode <= SWAPW(cmEndCodes[index])) {

        if (cmIdRangeOffset[index] == 0) {

            result = (LEGlyphID) unicode;

        } else {

            le_uint16 offset = unicode - SWAPW(cmStartCodes[index]);

            le_uint16 rangeOffset = SWAPW(cmIdRangeOffset[index]);

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

            result = SWAPW(glyphIndexTable[offset]);

        }

        result += SWAPW(cmIdDelta[index]);

    } else {

        result = 0;

    }

    return result;

}

le_uint16 FontObject::getUnitsPerEM()

{

    if (headTable == NULL) {

        LETag headTag = 0x68656164; // 'head'

        le_uint32 length;

        headTable = (HEADTable *) readTable(headTag, &length);

    }

    return SWAPW(headTable->unitsPerEm);

}

le_uint16 FontObject::getGlyphAdvance(LEGlyphID glyph)

{

    if (hmtxTable == NULL) {

        LETag maxpTag = 0x6D617870; // 'maxp'

        LETag hheaTag = 0x68686561; // 'hhea'

        LETag hmtxTag = 0x686D7478; // 'hmtx'

        le_uint32 length;

        HHEATable *hheaTable;

        MAXPTable *maxpTable = (MAXPTable *) readTable(maxpTag, &length);

        numGlyphs = SWAPW(maxpTable->numGlyphs);

        deleteTable(maxpTable);

        hheaTable = (HHEATable *) readTable(hheaTag, &length);

        numOfLongHorMetrics = SWAPW(hheaTable->numOfLongHorMetrics);

        deleteTable(hheaTable);

        hmtxTable = (HMTXTable *) readTable(hmtxTag, &length);

    }

    le_uint16 index = glyph;

    if (glyph >= numGlyphs) {

        return 0;

    }

    if (glyph >= numOfLongHorMetrics) {

        index = numOfLongHorMetrics - 1;

    }

    return SWAPW(hmtxTable->hMetrics[index].advanceWidth);

}