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
12 U_NAMESPACE_BEGIN
13
findLanguage(const LETableReference & base,LETag languageTag,LEErrorCode & success,le_bool exactMatch) const14 LEReferenceTo<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
findScript(const LETableReference & base,LETag scriptTag,LEErrorCode & success) const36 LEReferenceTo<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
findLanguage(const LETableReference & base,LETag scriptTag,LETag languageTag,LEErrorCode & success,le_bool exactMatch) const93 LEReferenceTo<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
104 U_NAMESPACE_END
105