add O(U)String::startsWith() to complement endsWith()

There's match(), with the second argument defaulting to 0, which
does the same, but that's pretty non-obvious.

Change-Id: Idd4de9388f53e1b5dc5d48446d1001af32c0af3d

sal/CppunitTest_sal_rtl_strings.mk

@@ -34,6 +34,7 @@ $(eval $(call gb_CppunitTest_add_exception_objects,sal_rtl_strings,\
     sal/qa/rtl/strings/test_oustring_convert \
     sal/qa/rtl/strings/test_oustring_endswith \
     sal/qa/rtl/strings/test_oustring_noadditional \
+    sal/qa/rtl/strings/test_oustring_startswith \
     sal/qa/rtl/strings/test_oustring_stringliterals \
 ))
 

sal/inc/rtl/string.hxx

@@ -662,6 +662,32 @@ public:
             literal, internal::ConstCharArrayDetector< T, void >::size - 1, internal::ConstCharArrayDetector< T, void >::size - 1 ) == 0;
     }
 
+    /**
+      Check whether this string starts with a given substring.
+
+      @param str  the substring to be compared
+
+      @return true if and only if the given str appears as a substring at the
+      start of this string
+
+      @since LibreOffice 3.7
+    */
+    bool startsWith(OString const & str) const {
+        return match(str, 0);
+    }
+
+    /**
+     @overload
+     This function accepts an ASCII string literal as its argument.
+     @since LibreOffice 3.7
+    */
+    template< typename T >
+    typename internal::ConstCharArrayDetector< T, bool >::Type startsWith( T& literal ) const
+    {
+        RTL_STRING_CONST_FUNCTION
+        return match(literal, 0);
+    }
+
     /**
       Check whether this string ends with a given substring.
 

sal/inc/rtl/ustring.hxx

@@ -880,6 +880,65 @@ public:
         const;
 #endif
 
+    /**
+      Check whether this string starts with a given substring.
+
+      @param str  the substring to be compared
+
+      @return true if and only if the given str appears as a substring at the
+      start of this string
+
+      @since LibreOffice 3.7
+    */
+    bool startsWith(OUString const & str) const {
+        return match(str, 0);
+    }
+
+    /**
+     @overload
+     This function accepts an ASCII string literal as its argument.
+     @since LibreOffice 3.7
+    */
+    template< typename T >
+    typename internal::ConstCharArrayDetector< T, bool >::Type startsWith( T& literal ) const
+    {
+        return rtl_ustr_asciil_reverseEquals_WithLength( pData->buffer, literal,
+                internal::ConstCharArrayDetector< T, void >::size - 1);
+    }
+
+    /**
+      Check whether this string starts with a given string, ignoring the case of
+      ASCII letters.
+
+      Character values between 65 and 90 (ASCII A-Z) are interpreted as
+      values between 97 and 122 (ASCII a-z).
+      This function can't be used for language specific comparison.
+
+      @param    str         the object (substring) to be compared.
+      @return true if this string starts with str, ignoring the case of ASCII
+      letters ("A"--"Z" and "a"--"z"); otherwise, false is returned
+      @since LibreOffice 3.7
+    */
+    sal_Bool startsWithIgnoreAsciiCase( const OUString & str ) const SAL_THROW(())
+    {
+        return matchIgnoreAsciiCase(str, 0);
+    }
+
+    /**
+     @overload
+     This function accepts an ASCII string literal as its argument.
+     @since LibreOffice 3.7
+    */
+    template< typename T >
+    typename internal::ConstCharArrayDetector< T, bool >::Type startsWithIgnoreAsciiCase( T& literal ) const SAL_THROW(())
+    {
+        return (rtl_ustr_ascii_compareIgnoreAsciiCase_WithLengths(
+                    pData->buffer,
+                    internal::ConstCharArrayDetector< T, void >::size - 1, literal,
+                    internal::ConstCharArrayDetector< T, void >::size - 1)
+                == 0);
+    }
+
     /**
       Check whether this string ends with a given substring.
 

sal/qa/rtl/strings/test_ostring_stringliterals.cxx

@@ -190,6 +190,9 @@ void test::ostring::StringLiterals::checkUsage()
     CPPUNIT_ASSERT( FooBaR.matchIgnoreAsciiCase( "fOo" ));
     CPPUNIT_ASSERT( rtl_string_unittest_const_literal_function == true );
     rtl_string_unittest_const_literal_function = false;
+    CPPUNIT_ASSERT( foobar.startsWith( "foo" ));
+    CPPUNIT_ASSERT( rtl_string_unittest_const_literal_function == true );
+    rtl_string_unittest_const_literal_function = false;
     CPPUNIT_ASSERT( foobar.endsWith( "bar" ));
     CPPUNIT_ASSERT( rtl_string_unittest_const_literal_function == true );
 //    rtl_string_unittest_const_literal_function = false;
@@ -249,6 +252,8 @@ void test::ostring::StringLiterals::checkNonConstUsage()
     CPPUNIT_ASSERT( FooBaRfoo.matchIgnoreAsciiCase( bAr_c, 3 ));
     CPPUNIT_ASSERT( FooBaR.matchIgnoreAsciiCase( (const char*)fOo_c ));
     CPPUNIT_ASSERT( FooBaR.matchIgnoreAsciiCase( fOo_c ));
+    CPPUNIT_ASSERT( foobar.startsWith( (const char*)foo_c ));
+    CPPUNIT_ASSERT( foobar.startsWith( foo_c ));
     CPPUNIT_ASSERT( foobar.endsWith( (const char*)bar_c ));
     CPPUNIT_ASSERT( foobar.endsWith( bar_c ));
 //    CPPUNIT_ASSERT( FooBaR.endsWithIgnoreAsciiCase( (const char*)bar_c ));

sal/qa/rtl/strings/test_oustring_startswith.cxx

+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*************************************************************************
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Copyright 2000, 2010 Oracle and/or its affiliates.
+ *
+ * OpenOffice.org - a multi-platform office productivity suite
+ *
+ * This file is part of OpenOffice.org.
+ *
+ * OpenOffice.org is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License version 3
+ * only, as published by the Free Software Foundation.
+ *
+ * OpenOffice.org is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License version 3 for more details
+ * (a copy is included in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * version 3 along with OpenOffice.org.  If not, see
+ * <http://www.openoffice.org/license.html>
+ * for a copy of the LGPLv3 License.
+ *
+ ************************************************************************/
+
+#include <sal/types.h>
+#include <cppunit/TestFixture.h>
+#include <cppunit/extensions/HelperMacros.h>
+#include "rtl/strbuf.hxx"
+#include "rtl/string.h"
+#include "rtl/string.hxx"
+#include "rtl/textenc.h"
+#include "rtl/ustring.hxx"
+#include "sal/types.h"
+#include <sal/macros.h>
+
+namespace test { namespace oustring {
+
+class StartsWith: public CppUnit::TestFixture
+{
+private:
+    void startsWith();
+
+    CPPUNIT_TEST_SUITE(StartsWith);
+    CPPUNIT_TEST(startsWith);
+    CPPUNIT_TEST_SUITE_END();
+};
+
+} }
+
+CPPUNIT_TEST_SUITE_REGISTRATION(test::oustring::StartsWith);
+
+void test::oustring::StartsWith::startsWith()
+{
+    CPPUNIT_ASSERT( rtl::OUString( "foobar" ).startsWith( "foo" ));
+    CPPUNIT_ASSERT( !rtl::OUString( "foo" ).startsWith( "foobar" ));
+    CPPUNIT_ASSERT( !rtl::OUString( "foobar" ).startsWith( "oo" ));
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

sal/qa/rtl/strings/test_oustring_stringliterals.cxx

@@ -129,6 +129,8 @@ void test::oustring::StringLiterals::checkUsage()
     CPPUNIT_ASSERT( foobar.match( "foo" ));
     CPPUNIT_ASSERT( FooBaRfoo.matchIgnoreAsciiCase( "bAr", 3 ));
     CPPUNIT_ASSERT( FooBaR.matchIgnoreAsciiCase( "fOo" ));
+    CPPUNIT_ASSERT( foobar.startsWith( "foo" ));
+    CPPUNIT_ASSERT( FooBaR.startsWithIgnoreAsciiCase( "foo" ));
     CPPUNIT_ASSERT( foobar.endsWith( "bar" ));
     CPPUNIT_ASSERT( FooBaR.endsWithIgnoreAsciiCase( "bar" ));
     CPPUNIT_ASSERT( foo == "foo" );