Merge pull request #14 from casperisfine/improve-buffered-io

Improve BufferedIO performance

lib/net/protocol.rb

@@ -120,6 +120,7 @@ def initialize(io, read_timeout: 60, write_timeout: 60, continue_timeout: nil, d
  @continue_timeout = continue_timeout
  @debug_output = debug_output
  @rbuf = ''.b
+ @rbuf_offset = 0
  end
 
  attr_reader :io
@@ -154,14 +155,15 @@ def read(len, dest = ''.b, ignore_eof = false)
  LOG "reading #{len} bytes..."
  read_bytes = 0
  begin
- while read_bytes + @rbuf.size < len
- s = rbuf_consume(@rbuf.size)
- read_bytes += s.size
- dest << s
+ while read_bytes + rbuf_size < len
+ if s = rbuf_consume_all_shareable!
+ read_bytes += s.bytesize
+ dest << s
+ end
  rbuf_fill
  end
  s = rbuf_consume(len - read_bytes)
- read_bytes += s.size
+ read_bytes += s.bytesize
  dest << s
  rescue EOFError
  raise unless ignore_eof
@@ -175,9 +177,10 @@ def read_all(dest = ''.b)
  read_bytes = 0
  begin
  while true
- s = rbuf_consume(@rbuf.size)
- read_bytes += s.size
- dest << s
+ if s = rbuf_consume_all_shareable!
+ read_bytes += s.bytesize
+ dest << s
+ end
  rbuf_fill
  end
  rescue EOFError
@@ -188,14 +191,16 @@ def read_all(dest = ''.b)
  end
 
  def readuntil(terminator, ignore_eof = false)
+ offset = @rbuf_offset
  begin
- until idx = @rbuf.index(terminator)
+ until idx = @rbuf.index(terminator, offset)
+ offset = @rbuf.bytesize
  rbuf_fill
  end
- return rbuf_consume(idx + terminator.size)
+ return rbuf_consume(idx + terminator.bytesize - @rbuf_offset)
  rescue EOFError
  raise unless ignore_eof
- return rbuf_consume(@rbuf.size)
+ return rbuf_consume
  end
  end
 
@@ -208,12 +213,16 @@ def readline
  BUFSIZE = 1024 * 16
 
  def rbuf_fill
- tmp = @rbuf.empty? ? @rbuf : nil
+ tmp = @rbuf_empty ? @rbuf : nil
  case rv = @io.read_nonblock(BUFSIZE, tmp, exception: false)
  when String
- return if rv.equal?(tmp)
- @rbuf << rv
- rv.clear
+ @rbuf_empty = false
+ if rv.equal?(tmp)
+ @rbuf_offset = 0
+ else
+ @rbuf << rv
+ rv.clear
+ end
  return
  when :wait_readable
  (io = @io.to_io).wait_readable(@read_timeout) or raise Net::ReadTimeout.new(io)
@@ -228,13 +237,50 @@ def rbuf_fill
  end while true
  end
 
- def rbuf_consume(len)
- if len == @rbuf.size
+ def rbuf_flush
+ if @rbuf_empty
+ @rbuf.clear
+ @rbuf_offset = 0
+ end
+ nil
+ end
+
+ def rbuf_size
+ @rbuf.bytesize - @rbuf_offset
+ end
+
+ # Warning: this method may share the buffer to avoid
+ # copying. The caller must no longer use the returned
+ # string once rbuf_fill has been called again
+ def rbuf_consume_all_shareable!
+ @rbuf_empty = true
+ buf = if @rbuf_offset == 0
+ @rbuf
+ else
+ @rbuf.byteslice(@rbuf_offset..-1)
+ end
+ @rbuf_offset = @rbuf.bytesize
+ buf
+ end
+
+ def rbuf_consume(len = nil)
+ if @rbuf_offset == 0 && (len.nil? || len == @rbuf.bytesize)
  s = @rbuf
  @rbuf = ''.b
+ @rbuf_offset = 0
+ @rbuf_empty = true
+ elsif len.nil?
+ s = @rbuf.byteslice(@rbuf_offset..-1)
+ @rbuf = ''.b
+ @rbuf_offset = 0
+ @rbuf_empty = true
  else
- s = @rbuf.slice!(0, len)
+ s = @rbuf.byteslice(@rbuf_offset, len)
+ @rbuf_offset += len
+ @rbuf_empty = @rbuf_offset == @rbuf.bytesize
+ rbuf_flush
  end
+
  @debug_output << %Q[-> #{s.dump}\n] if @debug_output
  s
  end