1/*
2 * (C) Copyright IBM Corp. 1998-2013 - All Rights Reserved
3 *
4 */
5
6#include "LETypes.h"
7#include "OpenTypeTables.h"
8#include "OpenTypeUtilities.h"
9#include "ScriptAndLanguage.h"
10#include "LESwaps.h"
11
12U_NAMESPACE_BEGIN
13
14LEReferenceTo<LangSysTable> ScriptTable::findLanguage(const LETableReference& base, LETag languageTag, LEErrorCode &success, le_bool exactMatch) const
15{
16    le_uint16 count = SWAPW(langSysCount);
17    Offset langSysTableOffset = exactMatch? 0 : SWAPW(defaultLangSysTableOffset);
18
19    if (count > 0) {
20      LEReferenceToArrayOf<TagAndOffsetRecord> langSysRecords(base, success, langSysRecordArray, count);
21      Offset foundOffset =
22        OpenTypeUtilities::getTagOffset(languageTag, langSysRecords, success);
23
24      if (foundOffset != 0 && LE_SUCCESS(success)) {
25        langSysTableOffset = foundOffset;
26      }
27    }
28
29    if (langSysTableOffset != 0) {
30      return LEReferenceTo<LangSysTable>(base, success, langSysTableOffset);
31    }
32
33    return LEReferenceTo<LangSysTable>();
34}
35
36LEReferenceTo<ScriptTable> ScriptListTable::findScript(const LETableReference &base, LETag scriptTag, LEErrorCode &success) const
37{
38    if (LE_FAILURE(success) ) {
39      return LEReferenceTo<ScriptTable>(); // get out
40    }
41    /*
42     * There are some fonts that have a large, bogus value for scriptCount. To try
43     * and protect against this, we use the offset in the first scriptRecord,
44     * which we know has to be past the end of the scriptRecordArray, to compute
45     * a value which is greater than or equal to the actual script count.
46     *
47     * Note: normally, the first offset will point to just after the scriptRecordArray,
48     * but there's no guarantee of this, only that it's *after* the scriptRecordArray.
49     * Because of this, a binary serach isn't safe, because the new count may include
50     * data that's not actually in the scriptRecordArray and hence the array will appear
51     * to be unsorted.
52     */
53    le_uint16 count = SWAPW(scriptCount);
54
55    if (count == 0) {
56      return LEReferenceTo<ScriptTable>(); // no items, no search
57    }
58
59    // attempt to construct a ref with at least one element
60    LEReferenceToArrayOf<ScriptRecord> oneElementTable(base, success, &scriptRecordArray[0], 1);
61
62    if( LE_FAILURE(success) ) {
63      return LEReferenceTo<ScriptTable>(); // couldn't even read the first record - bad font.
64    }
65
66    le_uint16 limit = ((SWAPW(scriptRecordArray[0].offset) - sizeof(ScriptListTable)) / sizeof(scriptRecordArray)) + ANY_NUMBER;
67    Offset scriptTableOffset = 0;
68
69
70    if (count > limit) {
71        // the scriptCount value is bogus; do a linear search
72        // because limit may still be too large.
73        LEReferenceToArrayOf<ScriptRecord> scriptRecordArrayRef(base, success, &scriptRecordArray[0], limit);
74        for(le_int32 s = 0; (s < limit)&&LE_SUCCESS(success); s += 1) {
75          if (SWAPT(scriptRecordArrayRef(s,success).tag) == scriptTag) {
76            scriptTableOffset = SWAPW(scriptRecordArrayRef(s,success).offset);
77            break;
78          }
79        }
80    } else {
81      LEReferenceToArrayOf<ScriptRecord> scriptRecordArrayRef(base, success, &scriptRecordArray[0], count);
82
83      scriptTableOffset = OpenTypeUtilities::getTagOffset(scriptTag, scriptRecordArrayRef, success);
84    }
85
86    if (scriptTableOffset != 0) {
87      return LEReferenceTo<ScriptTable>(base, success, scriptTableOffset);
88    }
89
90  return LEReferenceTo<ScriptTable>();
91}
92
93LEReferenceTo<LangSysTable>  ScriptListTable::findLanguage(const LETableReference &base, LETag scriptTag, LETag languageTag, LEErrorCode &success, le_bool exactMatch) const
94{
95  const LEReferenceTo<ScriptTable> scriptTable = findScript(base, scriptTag, success);
96
97  if (scriptTable.isEmpty()) {
98    return LEReferenceTo<LangSysTable>();
99  }
100
101  return scriptTable->findLanguage(scriptTable, languageTag, success, exactMatch).reparent(base);
102}
103
104U_NAMESPACE_END
105