From 1d098c1f50ed51470984cef87df46a64a4475634 Mon Sep 17 00:00:00 2001
From: Martchus <martchus@gmx.net>
Date: Sat, 1 Jun 2019 12:33:24 +0200
Subject: [PATCH] Fix TagValue::operator== if 0 byte contained

---
 tagvalue.cpp       | 22 +++++++++++++++++++---
 tests/tagvalue.cpp |  8 ++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/tagvalue.cpp b/tagvalue.cpp
index b12b718..6cfecee 100644
--- a/tagvalue.cpp
+++ b/tagvalue.cpp
@@ -117,11 +117,19 @@ bool TagValue::operator==(const TagValue &other) const
     if (m_type == other.m_type) {
         switch (m_type) {
         case TagDataType::Text:
-            if (m_size != other.m_size && m_encoding != other.m_encoding) {
+            if (m_size != other.m_size || m_encoding != other.m_encoding) {
                 // don't consider differently encoded text values equal
                 return false;
             }
-            return strncmp(m_ptr.get(), other.m_ptr.get(), m_size) == 0;
+            if (!m_size) {
+                return true;
+            }
+            for (auto i1 = m_ptr.get(), i2 = other.m_ptr.get(), end = m_ptr.get() + m_size; i1 != end; ++i1, ++i2) {
+                if (*i1 != *i2) {
+                    return false;
+                }
+            }
+            return true;
         case TagDataType::PositionInSet:
             return toPositionInSet() == other.toPositionInSet();
         case TagDataType::Integer:
@@ -138,7 +146,15 @@ bool TagValue::operator==(const TagValue &other) const
             if (m_size != other.m_size) {
                 return false;
             }
-            return strncmp(m_ptr.get(), other.m_ptr.get(), m_size) == 0;
+            if (!m_size) {
+                return true;
+            }
+            for (auto i1 = m_ptr.get(), i2 = other.m_ptr.get(), end = m_ptr.get() + m_size; i1 != end; ++i1, ++i2) {
+                if (*i1 != *i2) {
+                    return false;
+                }
+            }
+            return true;
         }
         return false;
     }
diff --git a/tests/tagvalue.cpp b/tests/tagvalue.cpp
index 2f23bc1..1b670db 100644
--- a/tests/tagvalue.cpp
+++ b/tests/tagvalue.cpp
@@ -195,6 +195,14 @@ void TagValueTests::testEqualityOperator()
     CPPUNIT_ASSERT_MESSAGE("equality requires identical types or identical string representation"s, TagValue(0) != TagValue::empty());
     CPPUNIT_ASSERT_EQUAL_MESSAGE("types might differ"s, TagValue(15), TagValue(15));
     CPPUNIT_ASSERT_EQUAL_MESSAGE("types might differ"s, TagValue("15", 2, TagTextEncoding::Latin1), TagValue(15));
+    CPPUNIT_ASSERT_EQUAL_MESSAGE("comparision of equal UTF-16 strings"s, TagValue("\x31\0\x32\0", 4, TagTextEncoding::Utf16LittleEndian),
+        TagValue("\x31\0\x32\0", 4, TagTextEncoding::Utf16LittleEndian));
+    CPPUNIT_ASSERT_MESSAGE("comparision of different UTF-16 strings"s,
+        TagValue("\x31\0\x33\0", 4, TagTextEncoding::Utf16LittleEndian) != TagValue("\x31\0\x32\0", 4, TagTextEncoding::Utf16LittleEndian));
+    CPPUNIT_ASSERT_EQUAL_MESSAGE(
+        "comparision of equal binary data"s, TagValue("\x31\0\x32\0", 4, TagDataType::Binary), TagValue("\x31\0\x32\0", 4, TagDataType::Binary));
+    CPPUNIT_ASSERT_MESSAGE("comparision of different binary data"s,
+        TagValue("\x31\0\x33\0", 4, TagDataType::Binary) != TagValue("\x31\0\x32\0", 4, TagDataType::Binary));
     CPPUNIT_ASSERT_MESSAGE("encoding must be equal if relevant for types"s,
         TagValue("\0\x31\0\x35", 4, TagTextEncoding::Utf16BigEndian) != TagValue("15", 2, TagTextEncoding::Latin1));
     CPPUNIT_ASSERT_EQUAL_MESSAGE(