public: better fix for ExtractFilePath

public/crtlib.c

@@ -642,20 +642,13 @@ COM_ExtractFilePath
 */
 void COM_ExtractFilePath( const char *path, char *dest )
 {
-	size_t len = Q_strlen( path );
+	const char *src = path + Q_strlen( path ) - 1;
-	const char *src = path + len - 1;
-
-	if( len == 0 )
-	{
-		dest[0] = 0;
-		return;
-	}
 
 	// back up until a \ or the start
-	while( src != path && !(*(src - 1) == '\\' || *(src - 1) == '/' ))
+	while( src > path && !(*(src - 1) == '\\' || *(src - 1) == '/' ))
 		src--;
 
-	if( src != path )
+	if( src > path )
 	{
 		memcpy( dest, path, src - path );
 		dest[src - path - 1] = 0; // cutoff backslash

public/tests/test_efp.c

@@ -0,0 +1,40 @@
+#include <stdlib.h>
+#include "crtlib.h"
+#include <stdio.h>
+
+int Test_ExtractFilePath( void )
+{
+	char dst[64];
+	const char *strings[] =
+	{
+		"dir/file", "dir",
+		"bark\\meow", "bark",
+		"nopath", "",
+		"knee/deep/in/paths", "knee/deep/in",
+		// yes, it removes the behavior/ even if it might be technically a directory
+		"keep/the/original/func/behavior/", "keep/the/original/func",
+		"backslashes\\are\\annoying\\af", "backslashes\\are\\annoying",
+		"", ""
+	};
+	size_t i;
+
+	for( i = 0; i < sizeof( strings ) / sizeof( strings[0] ); i += 2 )
+	{
+		COM_ExtractFilePath( strings[i], dst );
+		if( Q_strcmp( dst, strings[i+1] ))
+		{
+			printf( "%s %s %s\n", strings[i], strings[i+1], dst );
+			return (i >> 1) + 1;
+		}
+	}
+
+	return 0;
+}
+
+int main( void )
+{
+	if( Test_ExtractFilePath( ))
+		return EXIT_FAILURE;
+
+	return EXIT_SUCCESS;
+}

public/wscript

@@ -28,6 +28,7 @@ def build(bld):
 			'strings': 'tests/test_strings.c',
 			'build': 'tests/test_build.c',
 			'filebase': 'tests/test_filebase.c',
+			'efp': 'tests/test_efp.c',
 		}
 
 		for i in tests: