fix relying on integer underflow

lvandeve · May 3, 2016 · db9cc96 · db9cc96
1 parent c6cf08b
commit db9cc96
Showing 1 changed file with 3 additions and 2 deletions.
diff --git a/lodepng.cpp b/lodepng.cpp
@@ -2385,9 +2385,10 @@ static unsigned readBitsFromReversedStream(size_t* bitpointer, const unsigned ch
 {
   unsigned result = 0;
   size_t i;
-  for(i = nbits - 1; i < nbits; --i)
+  for(i = 0 ; i < nbits; ++i)
   {
-    result += (unsigned)readBitFromReversedStream(bitpointer, bitstream) << i;
+    result <<= 1;
+    result |= (unsigned)readBitFromReversedStream(bitpointer, bitstream);
   }
   return result;
 }