From 6cc572439564a32f7e80b6cc8eba02b233976f62 Mon Sep 17 00:00:00 2001
From: "zik.saleeba" <zik.saleeba@21eae674-98b7-11dd-bd71-f92a316d2d60>
Date: Wed, 21 Jul 2010 05:45:44 +0000
Subject: [PATCH] Added fix from Duncan Forster for bug #85

git-svn-id: http://picoc.googlecode.com/svn/trunk@468 21eae674-98b7-11dd-bd71-f92a316d2d60
---
 expression.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/expression.c b/expression.c
index 54ec890..1ba2db9 100644
--- a/expression.c
+++ b/expression.c
@@ -771,6 +771,24 @@ void ExpressionInfixOperator(struct ParseState *Parser, struct ExpressionStack *
             ExpressionAssign(Parser, BottomValue, TopValue, FALSE, NULL, 0, FALSE);
             ExpressionStackPushValueNode(Parser, StackTop, BottomValue);
         }
+        else if (Op == TokenAddAssign || Op == TokenSubtractAssign)
+        {
+            /* pointer arithmetic */
+            int Size = TypeSize(BottomValue->Typ->FromType, 0, TRUE);
+
+            Pointer = BottomValue->Val->Pointer;
+            if (Pointer == NULL)
+                ProgramFail(Parser, "invalid use of a NULL pointer");
+
+            if (Op == TokenAddAssign)
+                Pointer = (void *)((char *)Pointer + TopInt * Size);
+            else
+                Pointer = (void *)((char *)Pointer - TopInt * Size);
+
+            HeapUnpopStack(sizeof(struct Value));   /* XXX - possible bug if lvalue is a temp value and takes more than sizeof(struct Value) */
+            BottomValue->Val->Pointer = Pointer;
+            ExpressionStackPushValueNode(Parser, StackTop, BottomValue);
+        }
         else
             ProgramFail(Parser, "invalid operation");
     }