icuSources/test/letest/FontObject.cpp

   1 // © 2016 and later: Unicode, Inc. and others.
   2 // License & terms of use: http://www.unicode.org/copyright.html
   3 /***************************************************************************
   4 *
   5 *   Copyright (C) 1998-2002, International Business Machines
   6 *   Corporation and others.  All Rights Reserved.
   7 *
   8 ************************************************************************/
   9
  10 #include <stdio.h>
  11
  12 #include "LETypes.h"
  13 #include "FontObject.h"
  14 #include "LESwaps.h"
  15
  16 FontObject::FontObject(char *fileName)
  17   : directory(NULL), numTables(0), searchRange(0),entrySelector(0),
  18     cmapTable(NULL), cmSegCount(0), cmSearchRange(0), cmEntrySelector(0),
  19     cmEndCodes(NULL), cmStartCodes(NULL), cmIdDelta(0), cmIdRangeOffset(0),
  20     headTable(NULL), hmtxTable(NULL), numGlyphs(0), numOfLongHorMetrics(0), file(NULL)
  21 {
  22     file = fopen(fileName, "rb");
  23
  24     if (file == NULL) {
  25         printf("?? Couldn't open %s", fileName);
  26         return;
  27     }
  28
  29     SFNTDirectory tempDir;
  30
  31     fread(&tempDir, sizeof tempDir, 1, file);
  32
  33     numTables       = SWAPW(tempDir.numTables);
  34     searchRange     = SWAPW(tempDir.searchRange) >> 4;
  35     entrySelector   = SWAPW(tempDir.entrySelector);
  36     rangeShift      = SWAPW(tempDir.rangeShift) >> 4;
  37
  38     int dirSize = sizeof tempDir + ((numTables - ANY_NUMBER) * sizeof(DirectoryEntry));
  39
  40     directory = (SFNTDirectory *) new char[dirSize];
  41
  42     fseek(file, 0L, SEEK_SET);
  43     fread(directory, sizeof(char), dirSize, file);
  44
  45     initUnicodeCMAP();
  46 }
  47
  48 FontObject::~FontObject()
  49 {
  50     fclose(file);
  51     delete[] directory;
  52     delete[] cmapTable;
  53     delete[] headTable;
  54     delete[] hmtxTable;
  55 }
  56
  57 void FontObject::deleteTable(void *table)
  58 {
  59     delete[] (char *) table;
  60 }
  61
  62 DirectoryEntry *FontObject::findTable(LETag tag)
  63 {
  64     le_uint16 table = 0;
  65     le_uint16 probe = 1 << entrySelector;
  66
  67     if (SWAPL(directory->tableDirectory[rangeShift].tag) <= tag) {
  68         table = rangeShift;
  69     }
  70
  71     while (probe > (1 << 0)) {
  72         probe >>= 1;
  73
  74         if (SWAPL(directory->tableDirectory[table + probe].tag) <= tag) {
  75             table += probe;
  76         }
  77     }
  78
  79     if (SWAPL(directory->tableDirectory[table].tag) == tag) {
  80         return &directory->tableDirectory[table];
  81     }
  82
  83     return NULL;
  84 }
  85
  86 void *FontObject::readTable(LETag tag, le_uint32 *length)
  87 {
  88     DirectoryEntry *entry = findTable(tag);
  89
  90     if (entry == NULL) {
  91         *length = 0;
  92         return NULL;
  93     }
  94
  95     *length = SWAPL(entry->length);
  96
  97     void *table = new char[*length];
  98
  99     fseek(file, SWAPL(entry->offset), SEEK_SET);
 100     fread(table, sizeof(char), *length, file);
 101
 102     return table;
 103 }
 104
 105 CMAPEncodingSubtable *FontObject::findCMAP(le_uint16 platformID, le_uint16 platformSpecificID)
 106 {
 107     LETag cmapTag = 0x636D6170; // 'cmap'
 108
 109     if (cmapTable == NULL) {
 110         le_uint32 length;
 111
 112         cmapTable = (CMAPTable *) readTable(cmapTag, &length);
 113     }
 114
 115     if (cmapTable != NULL) {
 116         le_uint16 i;
 117         le_uint16 nSubtables = SWAPW(cmapTable->numberSubtables);
 118
 119
 120         for (i = 0; i < nSubtables; i += 1) {
 121             CMAPEncodingSubtableHeader *esh = &cmapTable->encodingSubtableHeaders[i];
 122
 123             if (SWAPW(esh->platformID) == platformID &&
 124                 SWAPW(esh->platformSpecificID) == platformSpecificID) {
 125                 return (CMAPEncodingSubtable *) ((char *) cmapTable + SWAPL(esh->encodingOffset));
 126             }
 127         }
 128     }
 129
 130     return NULL;
 131 }
 132
 133 void FontObject::initUnicodeCMAP()
 134 {
 135     CMAPEncodingSubtable *encodingSubtable = findCMAP(3, 1);
 136
 137     if (encodingSubtable == 0 ||
 138         SWAPW(encodingSubtable->format) != 4) {
 139         printf("Can't find unicode 'cmap'");
 140         return;
 141     }
 142
 143     CMAPFormat4Encoding *header = (CMAPFormat4Encoding *) encodingSubtable;
 144
 145     cmSegCount = SWAPW(header->segCountX2) / 2;
 146     cmSearchRange = SWAPW(header->searchRange);
 147     cmEntrySelector = SWAPW(header->entrySelector);
 148     cmRangeShift = SWAPW(header->rangeShift) / 2;
 149     cmEndCodes = &header->endCodes[0];
 150     cmStartCodes = &header->endCodes[cmSegCount + 1]; // + 1 for reservedPad...
 151     cmIdDelta = &cmStartCodes[cmSegCount];
 152     cmIdRangeOffset = &cmIdDelta[cmSegCount];
 153 }
 154
 155 LEGlyphID FontObject::unicodeToGlyph(LEUnicode32 unicode32)
 156 {
 157     if (unicode32 >= 0x10000) {
 158         return 0;
 159     }
 160
 161     LEUnicode16 unicode = (LEUnicode16) unicode32;
 162     le_uint16 index = 0;
 163     le_uint16 probe = 1 << cmEntrySelector;
 164     LEGlyphID result = 0;
 165
 166     if (SWAPW(cmStartCodes[cmRangeShift]) <= unicode) {
 167         index = cmRangeShift;
 168     }
 169
 170     while (probe > (1 << 0)) {
 171         probe >>= 1;
 172
 173         if (SWAPW(cmStartCodes[index + probe]) <= unicode) {
 174             index += probe;
 175         }
 176     }
 177
 178     if (unicode >= SWAPW(cmStartCodes[index]) && unicode <= SWAPW(cmEndCodes[index])) {
 179         if (cmIdRangeOffset[index] == 0) {
 180             result = (LEGlyphID) unicode;
 181         } else {
 182             le_uint16 offset = unicode - SWAPW(cmStartCodes[index]);
 183             le_uint16 rangeOffset = SWAPW(cmIdRangeOffset[index]);
 184             le_uint16 *glyphIndexTable = (le_uint16 *) ((char *) &cmIdRangeOffset[index] + rangeOffset);
 185
 186             result = SWAPW(glyphIndexTable[offset]);
 187         }
 188
 189         result += SWAPW(cmIdDelta[index]);
 190     } else {
 191         result = 0;
 192     }
 193
 194     return result;
 195 }
 196
 197 le_uint16 FontObject::getUnitsPerEM()
 198 {
 199     if (headTable == NULL) {
 200         LETag headTag = 0x68656164; // 'head'
 201         le_uint32 length;
 202
 203         headTable = (HEADTable *) readTable(headTag, &length);
 204     }
 205
 206     return SWAPW(headTable->unitsPerEm);
 207 }
 208
 209 le_uint16 FontObject::getGlyphAdvance(LEGlyphID glyph)
 210 {
 211     if (hmtxTable == NULL) {
 212         LETag maxpTag = 0x6D617870; // 'maxp'
 213         LETag hheaTag = 0x68686561; // 'hhea'
 214         LETag hmtxTag = 0x686D7478; // 'hmtx'
 215         le_uint32 length;
 216         HHEATable *hheaTable;
 217         MAXPTable *maxpTable = (MAXPTable *) readTable(maxpTag, &length);
 218
 219         numGlyphs = SWAPW(maxpTable->numGlyphs);
 220         deleteTable(maxpTable);
 221
 222         hheaTable = (HHEATable *) readTable(hheaTag, &length);
 223         numOfLongHorMetrics = SWAPW(hheaTable->numOfLongHorMetrics);
 224         deleteTable(hheaTable);
 225
 226         hmtxTable = (HMTXTable *) readTable(hmtxTag, &length);
 227     }
 228
 229     le_uint16 index = glyph;
 230
 231     if (glyph >= numGlyphs) {
 232         return 0;
 233     }
 234
 235     if (glyph >= numOfLongHorMetrics) {
 236         index = numOfLongHorMetrics - 1;
 237     }
 238
 239     return SWAPW(hmtxTable->hMetrics[index].advanceWidth);
 240 }
 241
 242