Move string hash function into String class.

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

Change-Id: Id30f5a2a774cf5244dbc00da9649e95a532484be

3 files changed, 49 insertions, 0 deletions

diff --git a/include/rtl/string.h b/include/rtl/string.h
index 32344bfa4413..71e095561a37 100644
--- a/include/rtl/string.h
+++ b/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.
diff --git a/include/rtl/string.hxx b/include/rtl/string.hxx
index fb7283b3a801..24bb98052e40 100644
--- a/include/rtl/string.hxx
+++ b/include/rtl/string.hxx
@@ -892,6 +892,19 @@ public:
     }
 
     /**
+      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.
 
       @return   a hash code value for this object.
diff --git a/include/rtl/ustring.h b/include/rtl/ustring.h
index 80c6bccf7f3d..206989934628 100644
--- a/include/rtl/ustring.h
+++ b/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.