Class: Stupidedi::Reader::FileInput

Inherits:

AbstractInput

• Object
• AbstractInput
• Stupidedi::Reader::FileInput

show all

Defined in:

lib/stupidedi/reader/input/file_input.rb

Overview

Querying the Position (collapse)

• - column readonly

  Returns the value of attribute column.

• - (Integer) line readonly

  (see AbstractInput#line).

• - offset readonly

  Returns the value of attribute offset.

• - path readonly

  Returns the value of attribute path.

Instance Attribute Summary (collapse)

• - (IO) io readonly

Querying the Position (collapse)

• - (Position) position

  The Position value that describes the position of the input stream.

Reading the Input (collapse)

• - (String) at(n)
• - (Integer) index(value)

  Returns the smallest n, where #at(n) == element.

• - (String) take(n)

Advancing the Cursor (collapse)

• - (AbstractInput) drop(n)

  Advance the cursor forward n elements.

Testing the Input (collapse)

• - (Boolean) defined_at?(n)
• - (Boolean) empty?

Instance Method Summary (collapse)

• - (FileInput) initialize(io, offset = 0, line = 1, column = 1, size = io.stat.size) constructor

  A new instance of FileInput.

• - pretty_print(q)

Methods included from Inspect

#inspect

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# File 'lib/stupidedi/reader/input/file_input.rb', line 15

def initialize(io, offset = 0, line = 1, column = 1, size = io.stat.size)
  @io, @offset, @line, @column, @size =
    io, offset, line, column, size
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 31

def column
  @column
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 13

def io
  @io
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 28

def line
  @line
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 24

def offset
  @offset
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 34

def path
  @path
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 56

def at(n)
  raise ArgumentError, "n must be positive" unless n >= 0

  @io.seek(@offset + n)
  @io.read(1)
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 111

def defined_at?(n)
  n < @size
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 85

def drop(n)
  raise ArgumentError, "n must be positive" unless n >= 0

  @io.seek(@offset)
  prefix = @io.read(n)
  suffix = @io

  length = prefix.length
  count  = prefix.count("\n")

  column = unless count.zero?
             length - prefix.rindex("\n")
           else
             @column + length
           end

  copy(:offset => @offset + length,
       :line   => @line + count,
       :column => column,
       :size   => @size - length)
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 116

def empty?
  @io.eof?
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 64

def index(value)
  @io.seek(@offset)
  length = value.length

  # We need to start with value != buffer, and this is a reasonable guess
  buffer = "\377" * length

  until @io.eof?
    buffer.slice!(0)
    buffer << @io.read(1)

    if buffer == value
      return @io.tell - @offset - length
    end
  end
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 37

def position
  Position.new(@offset, @line, @column, @io.path)
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 124

def pretty_print(q)
  q.text("FileInput")
  q.group(2, "(", ")") do
    preview = take(4)
    preview = if preview.empty?
                "EOF"
              elsif preview.length <= 3
                preview.inspect
              else
                (preview.take(3) << "...").inspect
              end

    q.text preview
    q.text " at line #{@line}, column #{@column}, offset #{@offset}, file #{File.basename(@io.path)}"
  end
end

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# File 'lib/stupidedi/reader/input/file_input.rb', line 46

def take(n)
  @io.seek(@offset)

  # Calling @io.read with more than the number of available bytes will
  # return nil, so we have to calculate how many bytes remain
  @io.read((n <= @size) ? n : @size)
end