1 files changed, 16 insertions, 2 deletions
diff --git a/xpdf/JArithmeticDecoder.cc b/xpdf/JArithmeticDecoder.cc
index 56ddc31..92db326 100644
--- a/xpdf/JArithmeticDecoder.cc
+++ b/xpdf/JArithmeticDecoder.cc
@@ -92,10 +92,18 @@ JArithmeticDecoder::JArithmeticDecoder() {
   dataLen = 0;
   limitStream = gFalse;
   nBytesRead = 0;
+  readBuf = -1;
 }
 
 inline Guint JArithmeticDecoder::readByte() {
+  Guint x;
+
   if (limitStream) {
+    if (readBuf >= 0) {
+      x = (Guint)readBuf;
+      readBuf = -1;
+      return x;
+    }
     --dataLen;
     if (dataLen < 0) {
       return 0xff;
@@ -162,9 +170,15 @@ void JArithmeticDecoder::restart(int dataLenA) {
 
 void JArithmeticDecoder::cleanup() {
   if (limitStream) {
+    // This saves one extra byte of data from the end of packet i, to
+    // be used in packet i+1.  It's not clear from the JPEG 2000 spec
+    // exactly how this should work, but this kludge does seem to fix
+    // decode of some problematic JPEG 2000 streams.  It may actually
+    // be necessary to buffer an arbitrary number of bytes (not just
+    // one byte), but I haven't run into that case yet.
     while (dataLen > 0) {
-      buf0 = buf1;
-      buf1 = readByte();
+      readBuf = -1;
+      readBuf = readByte();
     }
   }
 }