Correct converting from bytes which are unsigned to int

(left shift is sign extended during promition).
Based on a patch submitted by Bill Burke.

diff --git a/java/src/FCGIMessage.java b/java/src/FCGIMessage.java
index bacdbde..9b94da6 100644 (file)
--- a/java/src/FCGIMessage.java
+++ b/java/src/FCGIMessage.java
@@ -42,13 +42,11 @@ private int  h_type;
 private int  h_requestID;      // 2 bytes
 private int  h_contentLength;  // 2 bytes
 private int  h_paddingLength;
-private int  h_reserved;
 /* 
  * FCGI BeginRequest body.
 */
 private int  br_role;          // 2 bytes
 private int  br_flags;
-private byte br_reserved[];    // 5 bytes
 
 private FCGIInputStream in;
 
@@ -97,29 +95,17 @@ private FCGIInputStream in;
                return(FCGIGlobalDefs.def_FCGIStreamRecord);
        }
 
-/* Put the unsigned bytes in the incoming FCGI header into 
-        * integer form for Java, concatinating bytes when needed, 
-        * and preserving the original byte value when appropriate.
-        * Dont let low byte sign extend if high byte is empty.
+    /* Put the unsigned bytes in the incoming FCGI header into 
+        * integer form for Java, concatinating bytes when needed. 
+        * Because Java has no unsigned byte type, we have to be careful
+        * about signed numeric promotion to int.
         */
        private void processHeaderBytes(byte[] hdrBuf){
-
-            h_version                  = (int)hdrBuf[0] & 0x000000ff;
-            h_type                     = (int)hdrBuf[1] & 0x000000ff;
-            h_requestID                =  (hdrBuf[2] << 8) + hdrBuf[3]; 
-            if ((hdrBuf[3] & 0x80) != 0  && (hdrBuf[2] & 0xff) == 0){
-                       h_requestID = h_requestID & 0x000000ff;
-            } else {
-                       h_requestID = h_requestID & 0x0000ffff;
-                       }
-            h_contentLength            =  (hdrBuf[4] << 8) + hdrBuf[5];
-            if ((hdrBuf[5] & 0x80) != 0  && (hdrBuf[4] & 0xff) == 0){
-                       h_contentLength = h_contentLength & 0x000000ff;
-            } else {
-                       h_contentLength = h_contentLength & 0x0000ffff;
-                       }       
-            h_paddingLength            = (int)hdrBuf[6] & 0x000000ff;
-            h_reserved                 = (int)hdrBuf[7] & 0x000000ff;
+        h_version = hdrBuf[0] & 0xFF;
+        h_type = hdrBuf[1] & 0xFF;
+        h_requestID = ((hdrBuf[2] & 0xFF) << 8) | (hdrBuf[3] & 0xFF);
+        h_contentLength = ((hdrBuf[4] & 0xFF) << 8) | (hdrBuf[5] & 0xFF);
+        h_paddingLength = hdrBuf[6] & 0xFF;
        }
 
        /*
@@ -175,11 +161,10 @@ private FCGIInputStream in;
                                  FCGIGlobalDefs.def_FCGIBeginReqBodyLen) {
                        return FCGIGlobalDefs.def_FCGIProtocolError;
                        }
-               br_flags = ((int)beginReqBody[2]) & 0x000000ff; 
+               br_flags = beginReqBody[2] & 0xFF;      
                in.request.keepConnection 
                        = (br_flags & FCGIGlobalDefs.def_FCGIKeepConn) != 0; 
-               br_role =  ((int)((beginReqBody[0] << 8) + beginReqBody[1])) 
-                                               & 0x0000ffff;   
+        br_role = ((beginReqBody[0] & 0xFF) << 8) | (beginReqBody[1] & 0xFF);  
                in.request.role = br_role;
                in.request.isBeginProcessed = true;
                return FCGIGlobalDefs.def_FCGIBeginRecord;
@@ -313,11 +298,12 @@ private FCGIInputStream in;
                                   in.setFCGIError(
                                        FCGIGlobalDefs.def_FCGIParamsError);
                                   return -1;
-                                  }
-                               nameLen = ((nameLen & 0x7f) << 24) 
-                                       + (lenBuff[0] << 16)
-                                       + (lenBuff[1] << 8) + lenBuff[2];
-                               }
+                }
+                nameLen = ((nameLen & 0x7f) << 24) 
+                    | ((lenBuff[0] & 0xFF) << 16)
+                    | ((lenBuff[1] & 0xFF) << 8)
+                    | (lenBuff[2] & 0xFF);
+            }
 
                        if ((valueLen = in.read()) == -1) {
                                in.setFCGIError(
@@ -329,21 +315,12 @@ private FCGIInputStream in;
                                   in.setFCGIError(
                                        FCGIGlobalDefs.def_FCGIParamsError);
                                   return -1;
-                                  }
-                               valueLen = ((valueLen & 0x7f) << 24) 
-                                       + (lenBuff[0] << 16)
-                                       + (lenBuff[1] << 8) + lenBuff[2];
-                       /* handle sign extention for only two bytes, since
-                        * max msg len is ffff.
-                        */
-                       if ((lenBuff[2] & 0x80) != 0  && 
-                                               (lenBuff[1] & 0xff) == 0){
-                               valueLen = (valueLen & 0x000000ff);
-                               }
-                       if ((lenBuff[1] & 0x80) != 0) { 
-                               valueLen = (valueLen & 0x0000ffff);     
-                               }
-               }
+                }
+                valueLen = ((valueLen & 0x7f) << 24) 
+                    | ((lenBuff[0] & 0xFF) << 16)
+                    | ((lenBuff[1] & 0xFF) << 8)
+                    | (lenBuff[2] & 0xFF);
+            }
 
                /* 
                 * nameLen and valueLen are now valid; read the name