Break out getTrailingInt from MODULE

This is not logic specific to MODULE. Breaking it out to
kicad_string.h acheives:

* Slimming of the MODULE interface
* Enables reuse of the function
* Enables testing of the function

Also add a test under qa_common for this function.

common/string.cpp

@@ -641,6 +641,29 @@ int SplitString( wxString  strToSplit,
 }
 
 
+int GetTrailingInt( const wxString& aStr )
+{
+    int number = 0;
+    int base = 1;
+
+    // Trim and extract the trailing numeric part
+    int index = aStr.Len() - 1;
+    while( index >= 0 )
+    {
+        const char chr = aStr.GetChar( index );
+
+        if( chr < '0' || chr > '9' )
+            break;
+
+        number += ( chr - '0' ) * base;
+        base *= 10;
+        index--;
+    }
+
+    return number;
+}
+
+
 wxString GetIllegalFileNameWxChars()
 {
     return FROM_UTF8( illegalFileNameChars );

include/class_board_item.h

@@ -71,7 +71,6 @@ class BOARD_ITEM : public EDA_ITEM
 protected:
     PCB_LAYER_ID    m_Layer;
 
-    static int getTrailingInt( const wxString& aStr );
     static int getNextNumberInSequence( const std::set<int>& aSeq, bool aFillSequenceGaps );
 
 public:

include/kicad_string.h

@@ -171,6 +171,13 @@ int SplitString( wxString  strToSplit,
                  wxString* strDigits,
                  wxString* strEnd );
 
+/**
+ * Gets the trailing int, if any, from a string.
+ * @param  aStr the string to check
+ * @return      the trailing int or 0 if none found
+ */
+int GetTrailingInt( const wxString& aStr );
+
 /**
  * Function GetIllegalFileNameWxChars
  * @return a wString object containing the illegal file name characters for all platforms.

pcbnew/class_board_item.cpp

@@ -95,29 +95,6 @@ void BOARD_ITEM::ViewGetLayers( int aLayers[], int& aCount ) const
 }
 
 
-int BOARD_ITEM::getTrailingInt( const wxString& aStr )
-{
-    int number = 0;
-    int base = 1;
-
-    // Trim and extract the trailing numeric part
-    int index = aStr.Len() - 1;
-    while( index >= 0 )
-    {
-        const char chr = aStr.GetChar( index );
-
-        if( chr < '0' || chr > '9' )
-            break;
-
-        number += ( chr - '0' ) * base;
-        base *= 10;
-        index--;
-    }
-
-    return number;
-}
-
-
 int BOARD_ITEM::getNextNumberInSequence( const std::set<int>& aSeq, bool aFillSequenceGaps)
 {
     if( aSeq.empty() )

pcbnew/class_module.cpp

@@ -1309,7 +1309,7 @@ wxString MODULE::GetNextPadName( bool aFillSequenceGaps ) const
     // Create a set of used pad numbers
     for( D_PAD* pad = PadsList(); pad; pad = pad->Next() )
     {
-        int padNumber = getTrailingInt( pad->GetName() );
+        int padNumber = GetTrailingInt( pad->GetName() );
         usedNumbers.insert( padNumber );
     }
 
@@ -1343,9 +1343,8 @@ wxString MODULE::GetReferencePrefix() const
 
 void MODULE::IncrementReference( int aDelta )
 {
-    SetReference( wxString::Format( wxT( "%s%i" ),
-                                    GetReferencePrefix(),
-                                    getTrailingInt( GetReference() ) + aDelta ) );
+    SetReference( wxString::Format(
+            wxT( "%s%i" ), GetReferencePrefix(), GetTrailingInt( GetReference() ) + aDelta ) );
 }
 
 

qa/common/CMakeLists.txt

@@ -41,6 +41,7 @@ set( common_srcs
     test_coroutine.cpp
     test_format_units.cpp
     test_hotkey_store.cpp
+    test_kicad_string.cpp
     test_title_block.cpp
     test_utf8.cpp
     test_wildcards_and_files_ext.cpp

qa/common/test_kicad_string.cpp

@@ -0,0 +1,61 @@
+/*
+ * This program source code file is part of KiCad, a free EDA CAD application.
+ *
+ * Copyright (C) 2018 KiCad Developers, see CHANGELOG.TXT for contributors.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, you may find one here:
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ * or you may search the http://www.gnu.org website for the version 2 license,
+ * or you may write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
+ */
+
+/**
+ * @file
+ * Test suite for general string functions
+ */
+
+#include <unit_test_utils/unit_test_utils.h>
+
+// Code under test
+#include <kicad_string.h>
+
+/**
+ * Declare the test suite
+ */
+BOOST_AUTO_TEST_SUITE( KicadString )
+
+/**
+ * Test the #GetTrailingInt method.
+ */
+BOOST_AUTO_TEST_CASE( TrailingInt )
+{
+    using CASE = std::pair<std::string, int>;
+
+    const std::vector<CASE> cases = {
+        { "", 0 }, { "foo", 0 },            // no int
+        { "0", 0 },                         // only int
+        { "42", 42 },                       // only int
+        { "1001", 1001 },                   // only int
+        { "Foo42", 42 }, { "12Foo42", 42 }, // only the trailing
+        { "12Foo4.2", 2 },                  // no dots
+    };
+
+    for( const auto& c : cases )
+    {
+        BOOST_CHECK_EQUAL( GetTrailingInt( c.first ), c.second );
+    }
+}
+
+BOOST_AUTO_TEST_SUITE_END()