Move string hash function into String class.

hashCode() seems to do sampling while creating the hash.
hashCode64() will not.

Change-Id: Id30f5a2a774cf5244dbc00da9649e95a532484be

include/rtl/string.h

@@ -277,6 +277,24 @@ SAL_DLLPUBLIC sal_Int32 SAL_CALL rtl_str_hashCode(
 SAL_DLLPUBLIC sal_Int32 SAL_CALL rtl_str_hashCode_WithLength(
         const sal_Char * str, sal_Int32 len ) SAL_THROW_EXTERN_C();
 
+/** Return a hash code (64bit) for a string.
+
+    It is not allowed to store the hash code persistently, because later
+    versions could return other hash codes.
+
+    @param str
+    a string.  Need not be null-terminated, but must be at least as long as
+    the specified len.
+
+    @param len
+    the length of the string.
+
+    @return
+    a hash code for the given string.
+ */
+SAL_DLLPUBLIC sal_uInt64 SAL_CALL rtl_str_hashCode64_WithLength(
+        const sal_Char * str, sal_Int32 len ) SAL_THROW_EXTERN_C();
+
 /** Search for the first occurrence of a character within a string.
 
     The string must be null-terminated.

include/rtl/string.hxx

@@ -891,6 +891,19 @@ public:
         return !( literal == rStr );
     }
 
+    /**
+      Returns a 64bit hash of the string data.
+      This hashes the entire data, while hashCode would do sampling for larger string sizes.
+
+      @return   a hash code value of the string data
+
+      @see hashCode() for simple hashes
+    */
+    sal_uInt64 hashCode64() const SAL_THROW(())
+    {
+        return rtl_str_hashCode64_WithLength( pData->buffer, pData->length );
+    }
+
     /**
       Returns a hashcode for this string.
 

include/rtl/ustring.h

@@ -551,6 +551,24 @@ SAL_DLLPUBLIC sal_Int32 SAL_CALL rtl_ustr_hashCode(
 SAL_DLLPUBLIC sal_Int32 SAL_CALL rtl_ustr_hashCode_WithLength(
         const sal_Unicode * str, sal_Int32 len ) SAL_THROW_EXTERN_C();
 
+/** Return a hash code (64bit) for a string.
+
+    It is not allowed to store the hash code persistently, because later
+    versions could return other hash codes.
+
+    @param str
+    a string.  Need not be null-terminated, but must be at least as long as
+    the specified len.
+
+    @param len
+    the length of the string.
+
+    @return
+    a hash code for the given string.
+ */
+SAL_DLLPUBLIC sal_uInt64 SAL_CALL rtl_ustr_hashCode64_WithLength(
+        const sal_Unicode * str, sal_Int32 len ) SAL_THROW_EXTERN_C();
+
 /** Search for the first occurrence of a character within a string.
 
     The string must be null-terminated.

sal/rtl/strtmpl.cxx

@@ -252,6 +252,19 @@ sal_Int32 SAL_CALL IMPL_RTL_STRNAME( hashCode )( const IMPL_RTL_STRCODE* pStr )
 
 /* ----------------------------------------------------------------------- */
 
+sal_uInt64 SAL_CALL IMPL_RTL_STRNAME( hashCode64_WithLength )( const IMPL_RTL_STRCODE* pStr,
+                                                               sal_Int32 nLen )
+    SAL_THROW_EXTERN_C()
+{
+    sal_uInt64 nHash = 0;
+
+    for( sal_Int32 i = 0; i < nLen; i++ )
+        nHash = (nHash << 5) - nHash + *pStr++;
+    return nHash;
+}
+
+/* ----------------------------------------------------------------------- */
+
 sal_Int32 SAL_CALL IMPL_RTL_STRNAME( hashCode_WithLength )( const IMPL_RTL_STRCODE* pStr,
                                                             sal_Int32 nLen )
     SAL_THROW_EXTERN_C()

sal/util/sal.map

@@ -221,6 +221,7 @@ UDK_3_0_0 {
         rtl_str_shortenedCompareIgnoreAsciiCase_WithLength;
         rtl_str_hashCode;
         rtl_str_hashCode_WithLength;
+        rtl_str_hashCode64_WithLength;
         rtl_str_indexOfChar;
         rtl_str_indexOfChar_WithLength;
         rtl_str_indexOfStr;

sd/source/core/sdpage2.cxx

@@ -54,16 +54,6 @@ using namespace ::com::sun::star::office;
 
 extern void NotifyDocumentEvent( SdDrawDocument* pDocument, const OUString& rEventName, const Reference< XInterface >& xSource );
 
-static sal_uInt64 lcl_getHash( OString aString )
-{
-    sal_Int32  len = aString.getLength();
-    sal_uInt64 nHash = 0;
-
-    for( sal_Int32 i = 0; i < len; i++ )
-        nHash = (nHash << 5) - nHash + aString[i];
-    return nHash;
-}
-
 /*************************************************************************
 |*
 |* Sets: names of layout, master page links and templates for presentation
@@ -615,7 +605,7 @@ OString SdPage::stringify() const
 
 sal_uInt64 SdPage::getHash() const
 {
-    return lcl_getHash( stringify() );
+    return stringify().hashCode64();
 }