107 lines
4.0 KiB
C++
107 lines
4.0 KiB
C++
// Copyright (C) 2016 and later: Unicode, Inc. and others.
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// License & terms of use: http://www.unicode.org/copyright.html
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/*
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* (C) Copyright IBM Corp. 1998-2013 - All Rights Reserved
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*
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*/
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#include "LETypes.h"
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#include "OpenTypeTables.h"
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#include "OpenTypeUtilities.h"
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#include "ScriptAndLanguage.h"
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#include "LESwaps.h"
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U_NAMESPACE_BEGIN
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LEReferenceTo<LangSysTable> ScriptTable::findLanguage(const LETableReference& base, LETag languageTag, LEErrorCode &success, le_bool exactMatch) const
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{
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le_uint16 count = SWAPW(langSysCount);
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Offset langSysTableOffset = exactMatch? 0 : SWAPW(defaultLangSysTableOffset);
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if (count > 0) {
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LEReferenceToArrayOf<TagAndOffsetRecord> langSysRecords(base, success, langSysRecordArray, count);
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Offset foundOffset =
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OpenTypeUtilities::getTagOffset(languageTag, langSysRecords, success);
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if (foundOffset != 0 && LE_SUCCESS(success)) {
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langSysTableOffset = foundOffset;
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}
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}
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if (langSysTableOffset != 0) {
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return LEReferenceTo<LangSysTable>(base, success, langSysTableOffset);
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}
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return LEReferenceTo<LangSysTable>();
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}
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LEReferenceTo<ScriptTable> ScriptListTable::findScript(const LETableReference &base, LETag scriptTag, LEErrorCode &success) const
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{
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if (LE_FAILURE(success) ) {
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return LEReferenceTo<ScriptTable>(); // get out
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}
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/*
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* There are some fonts that have a large, bogus value for scriptCount. To try
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* and protect against this, we use the offset in the first scriptRecord,
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* which we know has to be past the end of the scriptRecordArray, to compute
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* a value which is greater than or equal to the actual script count.
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*
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* Note: normally, the first offset will point to just after the scriptRecordArray,
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* but there's no guarantee of this, only that it's *after* the scriptRecordArray.
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* Because of this, a binary serach isn't safe, because the new count may include
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* data that's not actually in the scriptRecordArray and hence the array will appear
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* to be unsorted.
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*/
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le_uint16 count = SWAPW(scriptCount);
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if (count == 0) {
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return LEReferenceTo<ScriptTable>(); // no items, no search
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}
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// attempt to construct a ref with at least one element
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LEReferenceToArrayOf<ScriptRecord> oneElementTable(base, success, &scriptRecordArray[0], 1);
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if( LE_FAILURE(success) ) {
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return LEReferenceTo<ScriptTable>(); // couldn't even read the first record - bad font.
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}
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le_uint16 limit = ((SWAPW(scriptRecordArray[0].offset) - sizeof(ScriptListTable)) / sizeof(scriptRecordArray)) + ANY_NUMBER;
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Offset scriptTableOffset = 0;
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if (count > limit) {
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// the scriptCount value is bogus; do a linear search
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// because limit may still be too large.
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LEReferenceToArrayOf<ScriptRecord> scriptRecordArrayRef(base, success, &scriptRecordArray[0], limit);
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for(le_int32 s = 0; (s < limit)&&LE_SUCCESS(success); s += 1) {
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if (SWAPT(scriptRecordArrayRef(s,success).tag) == scriptTag) {
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scriptTableOffset = SWAPW(scriptRecordArrayRef(s,success).offset);
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break;
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}
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}
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} else {
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LEReferenceToArrayOf<ScriptRecord> scriptRecordArrayRef(base, success, &scriptRecordArray[0], count);
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scriptTableOffset = OpenTypeUtilities::getTagOffset(scriptTag, scriptRecordArrayRef, success);
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}
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if (scriptTableOffset != 0) {
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return LEReferenceTo<ScriptTable>(base, success, scriptTableOffset);
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}
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return LEReferenceTo<ScriptTable>();
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}
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LEReferenceTo<LangSysTable> ScriptListTable::findLanguage(const LETableReference &base, LETag scriptTag, LETag languageTag, LEErrorCode &success, le_bool exactMatch) const
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{
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const LEReferenceTo<ScriptTable> scriptTable = findScript(base, scriptTag, success);
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if (scriptTable.isEmpty()) {
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return LEReferenceTo<LangSysTable>();
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}
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return scriptTable->findLanguage(scriptTable, languageTag, success, exactMatch).reparent(base);
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}
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U_NAMESPACE_END
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