Write directly to file io instead of buffering the output in memory

2 files changed, 9 insertions, 11 deletions

diff --git a/lib/axlsx/util/buffered_zip_output_stream.rb b/lib/axlsx/util/buffered_zip_output_stream.rb
index 0025e9e2..b348dc55 100644
--- a/lib/axlsx/util/buffered_zip_output_stream.rb
+++ b/lib/axlsx/util/buffered_zip_output_stream.rb
@@ -18,19 +18,19 @@ module Axlsx
     # Create a temporary directory for writing files to.
     #
     # The directory and its contents are removed at the end of the block.
-    def self.open(file_name, encrypter = nil, &block)
+    def self.open(file_name, encrypter = nil)
       Zip::OutputStream.open(file_name, encrypter) do |zos|
         bzos = new(zos)
-        block.call(bzos)
+        yield(bzos)
       ensure
         bzos.flush if bzos
       end
     end
 
-    def self.write_buffer(io = ::StringIO.new, encrypter = nil, &block)
+    def self.write_buffer(io = ::StringIO.new, encrypter = nil)
       Zip::OutputStream.write_buffer(io, encrypter) do |zos|
         bzos = new(zos)
-        block.call(bzos)
+        yield(bzos)
       ensure
         bzos.flush if bzos
       end
@@ -51,7 +51,7 @@ module Axlsx
     alias << write
 
     def flush
-      return if @buffer.size == 0
+      return if @buffer.empty?
 
       @zos << @buffer
       @buffer.clear
diff --git a/lib/axlsx/util/zip_command.rb b/lib/axlsx/util/zip_command.rb
index 00faa942..e43ba03d 100644
--- a/lib/axlsx/util/zip_command.rb
+++ b/lib/axlsx/util/zip_command.rb
@@ -40,23 +40,21 @@ module Axlsx
       @current_file = "#{@dir}/#{entry.name}"
       @files << entry.name
       FileUtils.mkdir_p(File.dirname(@current_file))
+      @io = File.open(@current_file, "wb")
     end
 
     # Write to a buffer that will be written to the current entry
     def write(content)
-      @buffer << content
+      @io << content
     end
     alias << write
 
     private
 
     def write_file
-      if @current_file
-        @buffer.rewind
-        File.open(@current_file, "wb") { |f| f.write @buffer.read }
-      end
+      @io.close if @current_file
       @current_file = nil
-      @buffer = StringIO.new
+      @io = nil
     end
 
     def zip_parts(output)