diff --git a/lib/zip/ioextras.rb b/lib/zip/ioextras.rb
index e58e7f9..c458bb5 100755
--- a/lib/zip/ioextras.rb
+++ b/lib/zip/ioextras.rb
@@ -33,26 +33,28 @@ module IOExtras  #:nodoc:
     attr_accessor :lineno
 
     def read(numberOfBytes = nil, buf = nil)
-      buf = "" unless (buf)
+      tbuf = nil
 
-      if numberOfBytes
+      if @outputBuffer.length > 0
         if numberOfBytes <= @outputBuffer.length
-          buf[RANGE_ALL] = @outputBuffer.slice!(0, numberOfBytes)
+          tbuf = @outputBuffer.slice!(0, numberOfBytes)
         else
-          if @outputBuffer.length > 0
-            buf[RANGE_ALL] = @outputBuffer + sysread(numberOfBytes - @outputBuffer.length, buf)
-            @outputBuffer.slice!(RANGE_ALL)
-          else
-            buf[RANGE_ALL] = sysread(numberOfBytes, buf)
-          end
+          numberOfBytes -= @outputBuffer.length if (numberOfBytes)
+          rbuf = sysread(numberOfBytes, buf)
+          tbuf = @outputBuffer
+          tbuf << rbuf if (rbuf)
+          @outputBuffer = ""
         end
       else
-        if @outputBuffer.length > 0
-          buf[RANGE_ALL] = @outputBuffer + sysread(nil, buf)
-          @outputBuffer.slice!(RANGE_ALL)
-        else
-          buf[RANGE_ALL] = sysread(nil, buf)
-        end
+        tbuf = sysread(numberOfBytes, buf)
+      end
+
+      return nil unless (tbuf)
+
+      if buf
+        buf.replace(tbuf)
+      else
+        buf = tbuf
       end
 
       buf
diff --git a/lib/zip/zip.rb b/lib/zip/zip.rb
index 7340129..b268a2f 100755
--- a/lib/zip/zip.rb
+++ b/lib/zip/zip.rb
@@ -177,7 +177,7 @@ module Zip
       readEverything = (numberOfBytes == nil)
       while (readEverything || @outputBuffer.length < numberOfBytes)
 	break if internal_input_finished?
-	@outputBuffer << internal_produce_input
+	@outputBuffer << internal_produce_input(buf)
       end
       return value_when_finished if @outputBuffer.length==0 && input_finished?
       endIndex= numberOfBytes==nil ? @outputBuffer.length : numberOfBytes
@@ -199,8 +199,8 @@ module Zip
 
     private
 
-    def internal_produce_input
-      @zlibInflater.inflate(@inputStream.read(Decompressor::CHUNK_SIZE))
+    def internal_produce_input(buf = nil)
+      @zlibInflater.inflate(@inputStream.read(Decompressor::CHUNK_SIZE, buf))
     end
 
     def internal_input_finished?