1 /*
   2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.  Oracle designates this
   7  * particular file as subject to the "Classpath" exception as provided
   8  * by Oracle in the LICENSE file that accompanied this code.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 /*
  27  *
  28  *
  29  * (C) Copyright IBM Corp. 1998-2010 - All Rights Reserved
  30  *
  31  */
  32 
  33 #include "LETypes.h"
  34 #include "OpenTypeTables.h"
  35 #include "OpenTypeUtilities.h"
  36 #include "ScriptAndLanguage.h"
  37 #include "LESwaps.h"
  38 
  39 U_NAMESPACE_BEGIN
  40 
  41 LEReferenceTo<LangSysTable> ScriptTable::findLanguage(const LETableReference& base, LETag languageTag, LEErrorCode &success, le_bool exactMatch) const
  42 {
  43     le_uint16 count = SWAPW(langSysCount);
  44     Offset langSysTableOffset = exactMatch? 0 : SWAPW(defaultLangSysTableOffset);
  45 
  46     if (count > 0) {
  47       LEReferenceToArrayOf<TagAndOffsetRecord> langSysRecords(base, success, langSysRecordArray, count);
  48       Offset foundOffset =
  49         OpenTypeUtilities::getTagOffset(languageTag, langSysRecords, success);
  50 
  51       if (foundOffset != 0 && LE_SUCCESS(success)) {
  52         langSysTableOffset = foundOffset;
  53       }
  54     }
  55 
  56     if (langSysTableOffset != 0) {
  57       return LEReferenceTo<LangSysTable>(base, success, langSysTableOffset);
  58     }
  59 
  60     return LEReferenceTo<LangSysTable>();
  61 }
  62 
  63 LEReferenceTo<ScriptTable> ScriptListTable::findScript(const LETableReference &base, LETag scriptTag, LEErrorCode &success) const
  64 {
  65     if (LE_FAILURE(success) ) {
  66       return LEReferenceTo<ScriptTable>(); // get out
  67     }
  68     /*
  69      * There are some fonts that have a large, bogus value for scriptCount. To try
  70      * and protect against this, we use the offset in the first scriptRecord,
  71      * which we know has to be past the end of the scriptRecordArray, to compute
  72      * a value which is greater than or equal to the actual script count.
  73      *
  74      * Note: normally, the first offset will point to just after the scriptRecordArray,
  75      * but there's no guarantee of this, only that it's *after* the scriptRecordArray.
  76      * Because of this, a binary serach isn't safe, because the new count may include
  77      * data that's not actually in the scriptRecordArray and hence the array will appear
  78      * to be unsorted.
  79      */
  80     le_uint16 count = SWAPW(scriptCount);
  81 
  82     if (count == 0) {
  83       return LEReferenceTo<ScriptTable>(); // no items, no search
  84     }
  85 
  86     // attempt to construct a ref with at least one element
  87     LEReferenceToArrayOf<ScriptRecord> oneElementTable(base, success, &scriptRecordArray[0], 1);
  88 
  89     if( LE_FAILURE(success) ) {
  90       return LEReferenceTo<ScriptTable>(); // couldn't even read the first record - bad font.
  91     }
  92 
  93     le_uint16 limit = ((SWAPW(scriptRecordArray[0].offset) - sizeof(ScriptListTable)) / sizeof(scriptRecordArray)) + ANY_NUMBER;
  94     Offset scriptTableOffset = 0;
  95 
  96 
  97     if (count > limit) {
  98         // the scriptCount value is bogus; do a linear search
  99         // because limit may still be too large.
 100         LEReferenceToArrayOf<ScriptRecord> scriptRecordArrayRef(base, success, &scriptRecordArray[0], limit);
 101         for(le_int32 s = 0; (s < limit)&&LE_SUCCESS(success); s += 1) {
 102           if (SWAPT(scriptRecordArrayRef(s,success).tag) == scriptTag) {
 103             scriptTableOffset = SWAPW(scriptRecordArrayRef(s,success).offset);
 104             break;
 105           }
 106         }
 107     } else {
 108       LEReferenceToArrayOf<ScriptRecord> scriptRecordArrayRef(base, success, &scriptRecordArray[0], count);
 109       scriptTableOffset = OpenTypeUtilities::getTagOffset(scriptTag, scriptRecordArrayRef, success); // TODO
 110     }
 111 
 112     if (scriptTableOffset != 0) {
 113       return LEReferenceTo<ScriptTable>(base, success, scriptTableOffset);
 114     }
 115 
 116   return LEReferenceTo<ScriptTable>();
 117 }
 118 
 119 LEReferenceTo<LangSysTable>  ScriptListTable::findLanguage(const LETableReference &base, LETag scriptTag, LETag languageTag, LEErrorCode &success, le_bool exactMatch) const
 120 {
 121   const LEReferenceTo<ScriptTable> scriptTable = findScript(base, scriptTag, success);
 122 
 123   if (scriptTable.isEmpty()) {
 124     return LEReferenceTo<LangSysTable>();
 125   }
 126 
 127   return scriptTable->findLanguage(scriptTable, languageTag, success, exactMatch).reparent(base);
 128 }
 129 
 130 U_NAMESPACE_END