1 files changed, 57 insertions, 5 deletions

diff --git a/src/list.h b/src/list.h
index c587c1a..d8c5a4a 100644
--- a/src/list.h
+++ b/src/list.h
@@ -178,11 +178,11 @@ namespace Bu
 
         /**
          * Linked list template container.  This class is similar to the stl list
-         * class except for a few minor changes.  First, it doesn't mimic a stack or
-         * queue, use the Stack or Queue clasess for that.  Second, when const, all
-         * members are only accessable const.  Third, erasing a location does not
-         * invalidate the iterator, it simply points to the next valid location, or
-         * end() if there are no more.
+         * class except for a few minor changes.  First, when const, all
+         * members are only accessable const.  Second, erasing a location does not
+         * invalidate the iterator used, it simply points to the next valid
+         * location, or end() if there are no more.  Other iterators pointing to
+         * the deleted record will, of course, no longer be valid.
          *
          *@param value (typename) The type of data to store in your list
          *@param valuealloc (typename) Memory Allocator for your value type
@@ -506,6 +506,32 @@ namespace Bu
                                 return *this;
                         }
 
+                        iterator operator+( int iDelta )
+                        {
+                                iterator ret( *this );
+                                for( int j = 0; j < iDelta; j++ )
+                                {
+                                        if( ret.pLink == NULL )
+                                                throw Bu::ExceptionBase(
+                                                        "Attempt to iterate past begining of list.");
+                                        ret.pLink = ret.pLink->pNext;
+                                }
+                                return ret;
+                        }
+
+                        iterator operator-( int iDelta )
+                        {
+                                iterator ret( *this );
+                                for( int j = 0; j < iDelta; j++ )
+                                {
+                                        if( ret.pLink == NULL )
+                                                throw Bu::ExceptionBase(
+                                                        "Attempt to iterate past begining of list.");
+                                        ret.pLink = ret.pLink->pPrev;
+                                }
+                                return ret;
+                        }
+
                         operator bool()
                         {
                                 return pLink != NULL;
@@ -619,6 +645,32 @@ namespace Bu
                                 return *this;
                         }
 
+                        const_iterator operator+( int iDelta )
+                        {
+                                const_iterator ret( *this );
+                                for( int j = 0; j < iDelta; j++ )
+                                {
+                                        if( ret.pLink == NULL )
+                                                throw Bu::ExceptionBase(
+                                                        "Attempt to iterate past begining of list.");
+                                        ret.pLink = ret.pLink->pNext;
+                                }
+                                return ret;
+                        }
+
+                        const_iterator operator-( int iDelta )
+                        {
+                                const_iterator ret( *this );
+                                for( int j = 0; j < iDelta; j++ )
+                                {
+                                        if( ret.pLink == NULL )
+                                                throw Bu::ExceptionBase(
+                                                        "Attempt to iterate past begining of list.");
+                                        ret.pLink = ret.pLink->pPrev;
+                                }
+                                return ret;
+                        }
+
                         const_iterator &operator=( const iterator &oth )
                         {
                                 pLink = oth.pLink;