Hangul composition: use < base + count checks, not <= checks

Before Unicode 4.1.0 there was an error in the example code for Hangul
normalization that used <= on the ends of some ranges of values, where
they should have used < tests. This was faithfully copied but the need
for correction has only lately come to light.

Thanks to Ma Lin for pointing this out and providing the fix and
test-cases.

Fixes: QTBUG-71894
Pick-to:  6.2 6.1 5.15
Change-Id: I5c7fec1f9fac1f7a25b2d5e9c3109a90a7ff49e1
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/tests/auto/corelib/text/qchar/tst_qchar.cpp b/tests/auto/corelib/text/qchar/tst_qchar.cpp
index 0773fd7b82..3c621948fe 100644
--- a/tests/auto/corelib/text/qchar/tst_qchar.cpp
+++ b/tests/auto/corelib/text/qchar/tst_qchar.cpp
@@ -997,6 +997,25 @@ void tst_QChar::normalization_manual()
         QVERIFY(decomposed.normalized(QString::NormalizationForm_KD) == decomposed);
         QVERIFY(decomposed.normalized(QString::NormalizationForm_KC) == composed);
     }
+    // QTBUG-71894 - erratum fixed in Unicode 4.1.0; SCount bounds are < not <=
+    {
+        // Hangul compose, test 0x11a7:
+        const QChar c[] = { QChar(0xae30), QChar(0x11a7), {} };
+        const QChar d[] = { QChar(0x1100), QChar(0x1175), QChar(0x11a7), {} };
+        const QString composed(c, 2);
+        const QString decomposed(d, 3);
+
+        QCOMPARE(decomposed.normalized(QString::NormalizationForm_C), composed);
+    }
+    {
+        // Hangul compose, test 0x11c3:
+        const QChar c[] = { QChar(0xae30), QChar(0x11c3), {} };
+        const QChar d[] = { QChar(0x1100), QChar(0x1175), QChar(0x11c3), {} };
+        const QString composed(c, 2);
+        const QString decomposed(d, 3);
+
+        QCOMPARE(decomposed.normalized(QString::NormalizationForm_C), composed);
+    }
 }
 
 void tst_QChar::normalizationCorrections()