qHash: two arguments support for simple integer types (and QChar)

Change-Id: I24bed73422fb1d2e90cf3dd4e5375e249b3dcac4
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: João Abecasis <joao.abecasis@nokia.com>

diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index 533208d..2bc6cc4 100644 (file)
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -58,32 +58,32 @@ class QByteArray;
 class QString;
 class QStringRef;
 
-inline uint qHash(char key) { return uint(key); }
-inline uint qHash(uchar key) { return uint(key); }
-inline uint qHash(signed char key) { return uint(key); }
-inline uint qHash(ushort key) { return uint(key); }
-inline uint qHash(short key) { return uint(key); }
-inline uint qHash(uint key) { return key; }
-inline uint qHash(int key) { return uint(key); }
-inline uint qHash(ulong key)
+inline uint qHash(char key, uint seed = 0) { return uint(key) ^ seed; }
+inline uint qHash(uchar key, uint seed = 0) { return uint(key) ^ seed; }
+inline uint qHash(signed char key, uint seed = 0) { return uint(key) ^ seed; }
+inline uint qHash(ushort key, uint seed = 0) { return uint(key) ^ seed; }
+inline uint qHash(short key, uint seed = 0) { return uint(key) ^ seed; }
+inline uint qHash(uint key, uint seed = 0) { return key ^ seed; }
+inline uint qHash(int key, uint seed = 0) { return uint(key) ^ seed; }
+inline uint qHash(ulong key, uint seed = 0)
 {
     if (sizeof(ulong) > sizeof(uint)) {
-        return uint(((key >> (8 * sizeof(uint) - 1)) ^ key) & (~0U));
+        return uint(((key >> (8 * sizeof(uint) - 1)) ^ key) & (~0U)) ^ seed;
     } else {
-        return uint(key & (~0U));
+        return uint(key & (~0U)) ^ seed;
     }
 }
-inline uint qHash(long key) { return qHash(ulong(key)); }
-inline uint qHash(quint64 key)
+inline uint qHash(long key, uint seed = 0) { return qHash(ulong(key), seed); }
+inline uint qHash(quint64 key, uint seed = 0)
 {
     if (sizeof(quint64) > sizeof(uint)) {
-        return uint(((key >> (8 * sizeof(uint) - 1)) ^ key) & (~0U));
+        return uint(((key >> (8 * sizeof(uint) - 1)) ^ key) & (~0U)) ^ seed;
     } else {
-        return uint(key & (~0U));
+        return uint(key & (~0U)) ^ seed;
     }
 }
-inline uint qHash(qint64 key) { return qHash(quint64(key)); }
-inline uint qHash(QChar key) { return qHash(key.unicode()); }
+inline uint qHash(qint64 key, uint seed = 0) { return qHash(quint64(key), seed); }
+inline uint qHash(QChar key, uint seed = 0) { return qHash(key.unicode(), seed); }
 Q_CORE_EXPORT uint qHash(const QByteArray &key, uint seed = 0);
 Q_CORE_EXPORT uint qHash(const QString &key, uint seed = 0);
 Q_CORE_EXPORT uint qHash(const QStringRef &key, uint seed = 0);