lib/bio-bgzf/writer.rb in bio-bgzf-0.2.0 vs lib/bio-bgzf/writer.rb in bio-bgzf-0.2.1

@@ -1,15 +1,23 @@
+require 'zlib'
+
 module Bio::BGZF
   
   class Writer
     include Bio::BGZF
 
-    attr_reader :f, :buf
+    attr_reader :f, :buf, :level
 
-    def initialize(f)
+    # Return the virtual offset of the last {#write} call. This is a
+    # hook for e.g. building an index on the fly.
+    attr_reader :last_write_pos
+
+    def initialize(f, level=2)
       @f = f
+      @level = level
       @buf = ''
+      @buf_write_pos = 0
       if block_given?
         begin
           yield self
         ensure
           self.close
@@ -22,25 +30,33 @@
     end
 
     def write_buf
       if buf.size > 0
         raise "Buffer too large: #{buf.bytesize}" if buf.bytesize > MAX_BYTES
-        block = pack(buf)
+        block = pack(buf, level)
         f.write(block)
         @buf = ''
+        @buf_write_pos = tell
       end
     end
 
+    # @api private
+    def _cur_write_pos
+      @buf_write_pos + buf.bytesize
+    end
+
     def write(s)
       if s.bytesize > MAX_BYTES
         write_buf
+        @last_write_pos = _cur_write_pos
         _each_slice(s) do |slice|
           write(slice)
         end
       else
         if (s.bytesize + buf.bytesize) > MAX_BYTES
           write_buf
         end
+        @last_write_pos = _cur_write_pos
         buf << s
       end
     end
 
     def _each_slice(s)