From ff4de8ac02eb5f7bad4be800cc1fb6206f8fbd9c Mon Sep 17 00:00:00 2001
From: Mike Buland <eichlan@xagasoft.com>
Date: Mon, 20 Oct 2008 18:12:33 +0000
Subject: Hey, Bu::Array supports erasing elements in two distinct, yet
 flavourful ways.

---
 src/array.h | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)

(limited to 'src')

diff --git a/src/array.h b/src/array.h
index e8d8b30..30d281a 100644
--- a/src/array.h
+++ b/src/array.h
@@ -184,6 +184,26 @@ namespace Bu
 					iPos = -1;
 				return *this;
 			}
+			
+			iterator operator--( int )
+			{
+				if( iPos < 0 )
+					throw ArrayException(
+						"Cannot increment iterator past end of array.");
+					iPos--;
+				if( iPos < 0 )
+					iPos = -1;
+				return *this;
+			}
+			
+			iterator operator--()
+			{
+				if( iPos < src.getSize() )
+					iPos--;
+				if( iPos <= 0 )
+					iPos = -1;
+				return *this;
+			}
 
 			bool operator==( const iterator &oth )
 			{
@@ -247,6 +267,26 @@ namespace Bu
 					iPos = -1;
 				return *this;
 			}
+			
+			const_iterator operator--( int )
+			{
+				if( iPos < 0 )
+					throw ArrayException(
+						"Cannot increment iterator past end of array.");
+					iPos--;
+				if( iPos < 0 )
+					iPos = -1;
+				return *this;
+			}
+			
+			const_iterator operator--()
+			{
+				if( iPos < src.getSize() )
+					iPos--;
+				if( iPos <= 0 )
+					iPos = -1;
+				return *this;
+			}
 
 			bool operator==( const const_iterator &oth )
 			{
@@ -295,6 +335,45 @@ namespace Bu
 			return const_iterator( *this, -1 );
 		}
 
+		/**
+		 * If order is important, use this.  It will delete the suggested item
+		 * and move the rest of the data up a spot.  This is a time O(n)
+		 * operation.  If the order isn't important, check swapErase
+		 */
+		void erase( iterator i )
+		{
+			for( int j = i.iPos; j < iSize; j++ )
+			{
+				va.destroy( &pData[j] );
+				if( j == iSize-1 )
+				{
+					iSize--;
+					return;
+				}
+				va.construct( &pData[j], pData[j+1] );
+			}
+		}
+
+		/**
+		 * In order to make swapErase faster, what it does is swap the given
+		 * item in the array with the last item, then make the array shorter
+		 * by one.  It changes the order of the elements in the array, so it
+		 * should be used carefully, but it is time O(1) instead of O(n) like
+		 * erase.
+		 */
+		void swapErase( iterator i )
+		{
+			if( i.iPos == iSize-1 )
+			{
+				erase( i );
+				return;
+			}
+			va.destroy( &pData[i.iPos] );
+			va.construct( &pData[i.iPos], pData[iSize-1] );
+			va.destroy( &pData[iSize-1] );
+			iSize--;
+		}
+
 	private:
 		valuealloc va;
 		value *pData;
-- 
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