workaround issue where casing diff overflows signed short

there are two such codepoints were added in the Unicode 5.1:
  U+1D79  LATIN SMALL LETTER INSULAR G
  U+A77D  LATIN CAPITAL LETTER INSULAR G
two more of them were added in the Unicode 6.0:
  U+0265  LATIN SMALL LETTER TURNED H
  U+A78D  LATIN CAPITAL LETTER TURNED H
and two more were added in the Unicode 6.1:
  U+0266  LATIN SMALL LETTER H WITH HOOK
  U+A7AA  LATIN CAPITAL LETTER H WITH HOOK

we map them like special cases with length == 1
(note: all are in BMP which is checked explicitly in the generator)

Change-Id: I8a34164eb3ee2e575b7799cc12d4b96ad5bcd9c6
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Lars Knoll <lars.knoll@nokia.com>

3 files changed, 39 insertions, 11 deletions

diff --git a/src/corelib/tools/qchar.cpp b/src/corelib/tools/qchar.cpp
index 3034e430ef..74df59ab5b 100644
--- a/src/corelib/tools/qchar.cpp
+++ b/src/corelib/tools/qchar.cpp
@@ -1053,33 +1053,48 @@ template <typename T>
 static inline T toLowerCase_helper(T uc)
 {
     const QUnicodeTables::Properties *p = qGetProp(uc);
-    if (!p->lowerCaseSpecial)
-        return uc + p->lowerCaseDiff;
-    return uc;
+    if (p->lowerCaseSpecial) {
+        const ushort *specialCase = specialCaseMap + p->lowerCaseDiff;
+        if (*specialCase == 1)
+            return specialCase[1];
+    }
+    return uc + p->lowerCaseDiff;
 }
 
 template <typename T>
 static inline T toUpperCase_helper(T uc)
 {
     const QUnicodeTables::Properties *p = qGetProp(uc);
-    if (!p->upperCaseSpecial)
-        return uc + p->upperCaseDiff;
-    return uc;
+    if (p->upperCaseSpecial) {
+        const ushort *specialCase = specialCaseMap + p->upperCaseDiff;
+        if (*specialCase == 1)
+            return specialCase[1];
+    }
+    return uc + p->upperCaseDiff;
 }
 
 template <typename T>
 static inline T toTitleCase_helper(T uc)
 {
     const QUnicodeTables::Properties *p = qGetProp(uc);
-    if (!p->titleCaseSpecial)
-        return uc + p->titleCaseDiff;
-    return uc;
+    if (p->titleCaseSpecial) {
+        const ushort *specialCase = specialCaseMap + p->titleCaseDiff;
+        if (*specialCase == 1)
+            return specialCase[1];
+    }
+    return uc + p->titleCaseDiff;
 }
 
 template <typename T>
 static inline T toCaseFolded_helper(T uc)
 {
-    return uc + qGetProp(uc)->caseFoldDiff;
+    const QUnicodeTables::Properties *p = qGetProp(uc);
+    if (p->caseFoldSpecial) {
+        const ushort *specialCase = specialCaseMap + p->caseFoldDiff;
+        if (*specialCase == 1)
+            return specialCase[1];
+    }
+    return uc + p->caseFoldDiff;
 }
 
 /*!
diff --git a/src/corelib/tools/qstring.cpp b/src/corelib/tools/qstring.cpp
index 65b52f3229..39747aa3e9 100644
--- a/src/corelib/tools/qstring.cpp
+++ b/src/corelib/tools/qstring.cpp
@@ -5263,7 +5263,20 @@ QString QString::toCaseFolded() const
                     prop = qGetProp(*p);
                 }
                 if (prop->caseFoldSpecial) {
+                    const ushort *specialCase = specialCaseMap + prop->caseFoldDiff;
+                    ushort length = *specialCase++;
+#if 0
+                    int pos = pp - s.d->data;
+                    s.resize(s.d->size + length - 1);
+                    pp = s.d->data + pos;
+                    while (length--)
+                        *pp++ = *specialCase++;
+#else
                     //### we currently don't support full case foldings
+                    Q_ASSERT(length == 1);
+                    Q_UNUSED(length)
+                    *pp++ = *specialCase;
+#endif
                 } else {
                     *pp++ = *p + prop->caseFoldDiff;
                 }
diff --git a/src/corelib/tools/qunicodetables_p.h b/src/corelib/tools/qunicodetables_p.h
index 0b8115035c..d8f8340673 100644
--- a/src/corelib/tools/qunicodetables_p.h
+++ b/src/corelib/tools/qunicodetables_p.h
@@ -76,7 +76,7 @@ namespace QUnicodeTables {
         ushort lowerCaseSpecial : 1;
         ushort upperCaseSpecial : 1;
         ushort titleCaseSpecial : 1;
-        ushort caseFoldSpecial  : 1; /* currently unused */
+        ushort caseFoldSpecial  : 1;
         signed short mirrorDiff    : 16;
         signed short lowerCaseDiff : 16;
         signed short upperCaseDiff : 16;