Module: Wind::IO

Defined in:
lib/wind/io.rb

Overview

Core extensions for Ruby IO

Constant Summary collapse

BUFFER_SIZE =

The buffer size is set to result of ‘getconf PAGESIZE` or 4096 if that fails.

page_size

Instance Method Summary collapse

Instance Method Details

#each_line ⇒ ios or an_enumerator

Note:

Currently only tested on “regular” text files.

Note:

The buffer size is set to the result of ‘getconf PAGESIZE`, or if that fails, it is set to 4096.

A fast buffered version of IO#each_line.

In my initial tests, it is between 2 and 3.5 times faster than Ruby’s IO#each_line.

You can include Wind::IO in the File class and use this method just like IO#each_line.

Examples:

File.include Wind::IO
File.open(fname, "rt").each_line { |line| puts line }

Returns:

  • (ios or an_enumerator) —

    Returns ios if a block is given, else, returns an enumerator



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# File 'lib/wind/io.rb', line 52

def each_line
  return enum_for(:each_line) unless block_given?

  buf = ""
  prev_unfinished_line = ""

  while self.read(BUFFER_SIZE, buf)
    buf.scan(/^.*$\n?/).each do |str|
      if prev_unfinished_line.empty? && str[-1] == "\n"
        # str is a complete line, yield it
        yield str
      elsif prev_unfinished_line.empty?
        # str is the start of an unfinished line
        prev_unfinished_line = str
      elsif !prev_unfinished_line.empty? && str[-1] == "\n"
        # str is the conclusion of a prev_unfinished_line
        prev_unfinished_line << str

        # str is now finished, yield and reset
        yield prev_unfinished_line
        prev_unfinished_line = ""
      else
        # str is a continuation of a prev_unfinished_line
        prev_unfinished_line << str
      end
    end
  end
end