rtlib: fb_LeftSelf()

- fb_LeftSelf( s, 0 ) was failing to reduce the string to a length of zero
- declaration added to inc/fbc-int/string.bi

changelog.txt

@@ -41,6 +41,7 @@ Version 1.20.0
 - gas64: 'SI' word found in cvtsi2ss wrongly releasing RSI register (SARG)
 - sf.net #997: gcc backend: handle EXTERN "rtlib": preserve the internally mangled name but emit an extra prototype to map the internal name to the external ASM name
 - gfxlib2: Incorrect alpha blending in ALPHA put method - fix C implementation to avoid overflowing int type
+- rtlib: internal fb_LeftSelf( s, 0 ) was failing to reduce the string to a length of zero.
 
 
 Version 1.10.1

inc/fbc-int/string.bi

@@ -42,10 +42,12 @@ extern "rtlib"
 		size as integer              '' size of allocated memory
 	end type
 
-	'' VAR-LEN STRING API (STRING)
-	'' declare sub fb_StrDelete( byref s as const string )
+	'' VAR-LEN STRING API (FBSTRING)
+	declare sub fb_StrDelete( byval s as const FBSTRING ptr )
+	declare sub fb_LEFTSELF( byval dst as FBSTRING ptr, byval length as const integer )
 
-	declare sub fb_StrDelete alias "fb_StrDelete" ( byval s as const FBSTRING ptr )
+	'' VAR-LEN STRING API (STRING)
+	declare sub LEFTSELF alias "fb_LEFTSELF" ( byref dst as string, byval length as const integer )  
 
 end extern
 

src/compiler/rtl-string.bas

@@ -1897,7 +1897,7 @@
 			NULL, FB_RTL_OPT_OVER or FB_RTL_OPT_NOQB, _
 			2, _
 			{ _
-				( typeSetIsConst( FB_DATATYPE_STRING ), FB_PARAMMODE_BYREF, FALSE ), _
+				( FB_DATATYPE_STRING, FB_PARAMMODE_BYREF, FALSE ), _
 				( typeSetIsConst( FB_DATATYPE_INTEGER ), FB_PARAMMODE_BYVAL, FALSE ) _
 			} _
 		), _

src/rtlib/str_left.c

@@ -44,10 +44,10 @@ FBCALL FBSTRING *fb_LEFT( FBSTRING *src, ssize_t chars )
 /* 
 	Special case of a = left( a, n )
 	The string 'a' is not reallocated, only the string length field is adjusted
-	and a NUL terminator written. fbc does not optimize for this so to use 
-	it must be a direct call by the user.  Carefule, due the function declaration
-	does not check for fb_LEFTSELF( "lteral", n ) so if src is a temporary,
-	It just gets deleted.
+	and a NUL terminator written. fbc does not optimize for this so to use,
+	it must be a direct call by the user.  Careful, due the function declaration, it
+	does not check for fb_LEFTSELF( "literal", n ) so if src is a temporary,
+	it just gets deleted.
 */
 FBCALL void fb_LEFTSELF( FBSTRING *src, ssize_t chars )
 {
@@ -59,7 +59,7 @@ FBCALL void fb_LEFTSELF( FBSTRING *src, ssize_t chars )
 	FB_STRLOCK();
 
 	src_len = FB_STRSIZE( src );
-	if( (src->data != NULL)	&& (chars > 0) && (src_len > 0) )
+	if( (src->data != NULL)	&& (chars >= 0) && (src_len >= 0) )
 	{
 		if( chars > src_len )
 		{

tests/fbc-int/string.bas

@@ -68,4 +68,80 @@ SUITE( fbc_tests.fbc_int.string_ )
 
 	END_TEST
 
+	TEST( leftSelf_ )
+		dim s as string
+		var p = cast(fbc.FBSTRING ptr, @s)
+		dim size as integer
+
+		s = "abcdef"
+		CU_ASSERT( p->data <> NULL )
+		CU_ASSERT( p->len = 6 )
+		CU_ASSERT( p->size > 0 )
+		CU_ASSERT( s = "abcdef" )
+		size = p->size
+
+		FBC.LeftSelf( s, len(s) - 1 )
+		CU_ASSERT( p->data <> NULL )
+		CU_ASSERT( p->len = 5 )
+		CU_ASSERT( p->size = size )
+		CU_ASSERT( s = "abcde" )
+
+		FBC.LeftSelf( s, len(s) - 1 )
+		CU_ASSERT( p->data <> NULL )
+		CU_ASSERT( p->len = 4 )
+		CU_ASSERT( p->size = size )
+		CU_ASSERT( s = "abcd" )
+
+		FBC.LeftSelf( s, len(s) - 1 )
+		CU_ASSERT( p->data <> NULL )
+		CU_ASSERT( p->len = 3 )
+		CU_ASSERT( p->size = size )
+		CU_ASSERT( s = "abc" )
+
+		FBC.LeftSelf( s, len(s) - 1 )
+		CU_ASSERT( p->data <> NULL )
+		CU_ASSERT( p->len = 2 )
+		CU_ASSERT( p->size = size )
+		CU_ASSERT( s = "ab" )
+
+		FBC.LeftSelf( s, len(s) - 1 )
+		CU_ASSERT( p->data <> NULL )
+		CU_ASSERT( p->len = 1 )
+		CU_ASSERT( p->size = size )
+		CU_ASSERT( s = "a" )
+
+		FBC.LeftSelf( s, len(s) - 1 )
+		CU_ASSERT( p->data <> NULL )
+		CU_ASSERT( p->len = 0 )
+		CU_ASSERT( p->size = size )
+		CU_ASSERT( s = "" )
+
+		FBC.LeftSelf( s, len(s) - 1 )
+		CU_ASSERT( p->data <> NULL )
+		CU_ASSERT( p->len = 0 )
+		CU_ASSERT( p->size = size )
+		CU_ASSERT( s = "" )
+
+		FBC.LeftSelf( s, 0 )
+		CU_ASSERT( p->data <> NULL )
+		CU_ASSERT( p->len = 0 )
+		CU_ASSERT( p->size = size )
+		CU_ASSERT( s = "" )
+
+		'' delete string
+		s = ""
+		CU_ASSERT( p->data = NULL )
+		CU_ASSERT( p->len = 0 )
+		CU_ASSERT( p->size = 0 )
+
+		FBC.LeftSelf( s, 0 )
+		CU_ASSERT( p->data = NULL )
+		CU_ASSERT( p->len = 0 )
+		CU_ASSERT( p->size = 0 )
+
+	END_TEST
+
+	TEST( concat_no_resize )
+	END_TEST
+
 END_SUITE

tests/warnings/rtl-prototypes.bas

@@ -2939,7 +2939,7 @@
 
 	ID( sub fb_LeftSelf alias "fb_LEFTSELF" )
 	scope
-		dim chk as sub fbcall ( byref as const string, byval as const integer )
+		dim chk as sub fbcall ( byref as string, byval as const integer )
 		chk = procptr( fb_LeftSelf )
 	end scope