Fixed bug with byte overruns.

git-svn-id: https://svn.apache.org/repos/asf/jakarta/poi/trunk@352124 13f79535-47bb-0310-9956-ffa450edef68

3 files changed, 10 insertions, 2 deletions

diff --git a/src/java/org/apache/poi/hssf/record/FooterRecord.java b/src/java/org/apache/poi/hssf/record/FooterRecord.java
index 60879a67b3..7ef88b95e7 100644
--- a/src/java/org/apache/poi/hssf/record/FooterRecord.java
+++ b/src/java/org/apache/poi/hssf/record/FooterRecord.java
@@ -118,7 +118,7 @@ public class FooterRecord
         {
             field_1_footer_len = data[ 0 + offset ];
             field_2_footer     = new String(data, 1 + offset,
-                                            ( int ) field_1_footer_len);
+                                            LittleEndian.ubyteToInt( field_1_footer_len) );
         }
     }
 
diff --git a/src/java/org/apache/poi/hssf/record/HeaderRecord.java b/src/java/org/apache/poi/hssf/record/HeaderRecord.java
index 31946aa8ec..d5371b322c 100644
--- a/src/java/org/apache/poi/hssf/record/HeaderRecord.java
+++ b/src/java/org/apache/poi/hssf/record/HeaderRecord.java
@@ -118,7 +118,7 @@ public class HeaderRecord
         {
             field_1_header_len = data[ 0 + offset ];
             field_2_header     = new String(data, 1 + offset,
-                                            ( int ) field_1_header_len);
+                                            LittleEndian.ubyteToInt(field_1_header_len));
         }
     }
 
diff --git a/src/java/org/apache/poi/util/LittleEndian.java b/src/java/org/apache/poi/util/LittleEndian.java
index 2598721725..3d39cefc19 100644
--- a/src/java/org/apache/poi/util/LittleEndian.java
+++ b/src/java/org/apache/poi/util/LittleEndian.java
@@ -498,4 +498,12 @@ public class LittleEndian
             v         >>= 8;
         }
     }
+
+    /**
+     * Convert an 'unsigned' byte to an integer.  ie, don't carry across the sign.
+     */
+    public static int ubyteToInt(byte b)
+    {
+        return ((b & 0x80) == 0 ? (int)b : (int)(b & (byte)0x7f) + 0x80 );
+    }
 }