Merge pull request #6916 from asterite/opt/gzip-zlib-flate

Let Zlib::Reader, Gzip::Reader and Flate::Reader include IO::Buffered for optimized performance

spec/std/flate/flate_spec.cr

@@ -1,14 +1,18 @@
 require "spec"
 require "flate"
 
+private def new_sample_io
+  io = IO::Memory.new
+  "cbc9cc4b350402ae1c20c30808b800".scan(/../).each do |match|
+    io.write_byte match[0].to_u8(16)
+  end
+  io.rewind
+end
+
 module Flate
   describe Reader do
     it "should read byte by byte (#4192)" do
-      io = IO::Memory.new
-      "cbc9cc4b350402ae1c20c30808b800".scan(/../).each do |match|
-        io.write_byte match[0].to_u8(16)
-      end
-      io.rewind
+      io = new_sample_io
 
       reader = Reader.new(io)
 
@@ -21,6 +25,15 @@ module Flate
       str.should eq("line1111\nline2222\n")
     end
 
+    it "should rewind" do
+      io = new_sample_io
+
+      reader = Reader.new(io)
+      reader.gets.should eq("line1111")
+      reader.rewind
+      reader.gets_to_end.should eq("line1111\nline2222\n")
+    end
+
     describe ".open" do
       it "yields itself to block" do
         # Hello Crystal!

spec/std/gzip/gzip_spec.cr

@@ -1,46 +1,60 @@
 require "spec"
 require "gzip"
 
+private SAMPLE_TIME     = Time.utc(2016, 1, 2)
+private SAMPLE_OS       = 4_u8
+private SAMPLE_EXTRA    = Bytes[1, 2, 3]
+private SAMPLE_NAME     = "foo.txt"
+private SAMPLE_COMMENT  = "some comment"
+private SAMPLE_CONTENTS = "hello world\nfoo bar"
+
+private def new_sample_io
+  io = IO::Memory.new
+
+  Gzip::Writer.open(io) do |gzip|
+    header = gzip.header
+    header.modification_time = SAMPLE_TIME
+    header.os = SAMPLE_OS
+    header.extra = SAMPLE_EXTRA
+    header.name = SAMPLE_NAME
+    header.comment = SAMPLE_COMMENT
+
+    io.bytesize.should eq(0)
+    gzip.flush
+    io.bytesize.should_not eq(0)
+
+    gzip.print SAMPLE_CONTENTS
+  end
+
+  io.rewind
+end
+
 describe Gzip do
   it "writes and reads to memory" do
-    io = IO::Memory.new
-
-    time = Time.utc(2016, 1, 2)
-    os = 4_u8
-    extra = Bytes[1, 2, 3]
-    name = "foo.txt"
-    comment = "some comment"
-    contents = "hello world"
-
-    Gzip::Writer.open(io) do |gzip|
-      header = gzip.header
-      header.modification_time = time
-      header.os = os
-      header.extra = extra
-      header.name = name
-      header.comment = comment
-
-      io.bytesize.should eq(0)
-      gzip.flush
-      io.bytesize.should_not eq(0)
-
-      gzip.print contents
-    end
-
-    io.rewind
+    io = new_sample_io
 
     Gzip::Reader.open(io) do |gzip|
       header = gzip.header.not_nil!
-      header.modification_time.should eq(time)
-      header.os.should eq(os)
-      header.extra.should eq(extra)
-      header.name.should eq(name)
-      header.comment.should eq(comment)
+      header.modification_time.should eq(SAMPLE_TIME)
+      header.os.should eq(SAMPLE_OS)
+      header.extra.should eq(SAMPLE_EXTRA)
+      header.name.should eq(SAMPLE_NAME)
+      header.comment.should eq(SAMPLE_COMMENT)
 
       # Reading zero bytes is OK
       gzip.read(Bytes.empty).should eq(0)
 
-      gzip.gets_to_end.should eq(contents)
+      gzip.gets_to_end.should eq(SAMPLE_CONTENTS)
     end
   end
+
+  it "rewinds" do
+    io = new_sample_io
+
+    gzip = Gzip::Reader.new(io)
+    gzip.gets.should eq(SAMPLE_CONTENTS.lines.first)
+
+    gzip.rewind
+    gzip.gets_to_end.should eq(SAMPLE_CONTENTS)
+  end
 end

spec/std/zlib/reader_spec.cr

@@ -1,14 +1,18 @@
 require "spec"
 require "zlib"
 
+private def new_sample_io
+  io = IO::Memory.new
+  "789c2bc9c82c5600a2448592d4e21285e292a2ccbc74054520e00200854f087b".scan(/../).each do |match|
+    io.write_byte match[0].to_u8(16)
+  end
+  io.rewind
+end
+
 module Zlib
   describe Reader do
     it "should be able to read" do
-      io = IO::Memory.new
-      "789c2bc9c82c5600a2448592d4e21285e292a2ccbc74054520e00200854f087b".scan(/../).each do |match|
-        io.write_byte match[0].to_u8(16)
-      end
-      io.rewind
+      io = new_sample_io
 
       reader = Reader.new(io)
 
@@ -20,6 +24,15 @@ module Zlib
       reader.read(Bytes.new(10)).should eq(0)
     end
 
+    it "rewinds" do
+      io = new_sample_io
+
+      reader = Reader.new(io)
+      reader.gets(3).should eq("thi")
+      reader.rewind
+      reader.gets_to_end.should eq("this is a test string !!!!\n")
+    end
+
     it "can be closed without sync" do
       io = IO::Memory.new(Bytes[120, 156, 3, 0, 0, 0, 0, 1])
       reader = Reader.new(io)
@@ -56,11 +69,7 @@ module Zlib
     end
 
     it "should not freeze when reading empty slice" do
-      io = IO::Memory.new
-      "789c2bc9c82c5600a2448592d4e21285e292a2ccbc74054520e00200854f087b".scan(/../).each do |match|
-        io.write_byte match[0].to_u8(16)
-      end
-      io.rewind
+      io = new_sample_io
       reader = Reader.new(io)
       slice = Bytes.empty
       reader.read(slice).should eq(0)

src/flate/reader.cr

@@ -4,12 +4,17 @@
 # instance, it reads data from the underlying IO, decompresses it, and returns
 # it to the caller.
 class Flate::Reader < IO
+  include IO::Buffered
+
   # If `#sync_close?` is `true`, closing this IO will close the underlying IO.
   property? sync_close : Bool
 
   # Returns `true` if this reader is closed.
   getter? closed = false
 
+  # Dictionary passed in the constructor
+  getter dict : Bytes?
+
   # Peeked bytes from the underlying IO
   @peek : Bytes?
 
@@ -22,6 +27,7 @@ class Flate::Reader < IO
     ret = LibZ.inflateInit2(pointerof(@stream), -LibZ::MAX_BITS, LibZ.zlibVersion, sizeof(LibZ::ZStream))
     raise Flate::Error.new(ret, @stream) unless ret.ok?
 
+    @peek = nil
     @end = false
   end
 
@@ -46,12 +52,12 @@ class Flate::Reader < IO
   end
 
   # Always raises `IO::Error` because this is a read-only `IO`.
-  def write(slice : Bytes)
+  def unbuffered_write(slice : Bytes)
     raise IO::Error.new "Can't write to Flate::Reader"
   end
 
   # See `IO#read`.
-  def read(slice : Bytes)
+  def unbuffered_read(slice : Bytes)
     check_open
 
     return 0 if slice.empty?
@@ -119,8 +125,12 @@ class Flate::Reader < IO
     end
   end
 
+  def unbuffered_flush
+    raise IO::Error.new "Can't flush Flate::Reader"
+  end
+
   # Closes this reader.
-  def close
+  def unbuffered_close
     return if @closed
     @closed = true
 
@@ -130,6 +140,14 @@ class Flate::Reader < IO
     @io.close if @sync_close
   end
 
+  def unbuffered_rewind
+    raise IO::Error.new "Closed stream" if closed?
+
+    @io.rewind
+
+    initialize(@io, @sync_close, @dict)
+  end
+
   # :nodoc:
   def inspect(io)
     to_s(io)

src/gzip/reader.cr

@@ -27,6 +27,8 @@
 # string # => "abc"
 # ```
 class Gzip::Reader < IO
+  include IO::Buffered
+
   # Whether to close the enclosed `IO` when closing this reader.
   property? sync_close = false
 
@@ -73,7 +75,7 @@ class Gzip::Reader < IO
   end
 
   # See `IO#read`.
-  def read(slice : Bytes)
+  def unbuffered_read(slice : Bytes)
     check_open
 
     return 0 if slice.empty?
@@ -121,16 +123,31 @@ class Gzip::Reader < IO
   end
 
   # Always raises `IO::Error` because this is a read-only `IO`.
-  def write(slice : Bytes) : Nil
+  def unbuffered_write(slice : Bytes) : Nil
     raise IO::Error.new("Can't write to Gzip::Reader")
   end
 
+  def unbuffered_flush
+    raise IO::Error.new "Can't flush Gzip::Reader"
+  end
+
   # Closes this reader.
-  def close
+  def unbuffered_close
     return if @closed
     @closed = true
 
     @flate_io.try &.close
     @io.close if @sync_close
   end
+
+  def unbuffered_rewind
+    raise IO::Error.new "Closed stream" if closed?
+
+    @io.rewind
+
+    @header = nil
+    @flate_io = nil
+
+    initialize(@io, @sync_close)
+  end
 end

src/zlib/reader.cr

@@ -4,6 +4,8 @@
 # instance, it reads data from the underlying IO, decompresses it, and returns
 # it to the caller.
 class Zlib::Reader < IO
+  include IO::Buffered
+
   # Whether to close the enclosed `IO` when closing this reader.
   property? sync_close = false
 
@@ -56,7 +58,7 @@ class Zlib::Reader < IO
   end
 
   # See `IO#read`.
-  def read(slice : Bytes)
+  def unbuffered_read(slice : Bytes)
     check_open
 
     return 0 if slice.empty?
@@ -79,18 +81,30 @@ class Zlib::Reader < IO
   end
 
   # Always raises `IO::Error` because this is a read-only `IO`.
-  def write(slice : Bytes)
+  def unbuffered_write(slice : Bytes)
     raise IO::Error.new "Can't write to Zlib::Reader"
   end
 
-  def close
+  def unbuffered_flush
+    raise IO::Error.new "Can't flush Zlib::Reader"
+  end
+
+  def unbuffered_close
     return if @closed
     @closed = true
 
     @flate_io.close
     @io.close if @sync_close
   end
 
+  def unbuffered_rewind
+    raise IO::Error.new "Closed stream" if closed?
+
+    @io.rewind
+
+    initialize(@io, @sync_close, @flate_io.dict)
+  end
+
   protected def self.invalid_header
     raise Zlib::Error.new("Invalid header")
   end