Class: FixWidthTable

Inherits:
Object
  • Object
show all
Defined in:
lib/rbbt/fix_width_table.rb

Constant Summary collapse

CONNECTIONS = 
{}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(filename, value_size = nil, range = nil, update = false, in_memory = true) ⇒ FixWidthTable

Returns a new instance of FixWidthTable.



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# File 'lib/rbbt/fix_width_table.rb', line 4

def initialize(filename, value_size = nil, range = nil, update = false, in_memory = true)
  @filename = filename

  if update or %w(memory stringio).include?(filename.to_s.downcase) or not File.exists?(filename)
    Log.debug "FixWidthTable create: #{ filename }"
    @value_size  = value_size
    @range       = range
    @record_size = @value_size + (@range ? 12 : 4)

    if %w(memory stringio).include? filename.to_s.downcase
      @filename = :memory
      @file     = StringIO.new
    else
      FileUtils.rm @filename if File.exists? @filename
      @file = File.open(@filename, 'wb')
    end

    @file.write [value_size].pack("L")
    @file.write [@range ? 1 : 0 ].pack("C")
    @size = 0
  else
    Log.debug "FixWidthTable up-to-date: #{ filename }"
    if in_memory
      @file        = StringIO.new(Open.read(@filename, :mode => 'rb'), 'r')
    else
      @file        = File.open(@filename, 'r')
    end
    @value_size  = @file.read(4).unpack("L").first
    @range       = @file.read(1).unpack("C").first == 1
    @record_size = @value_size + (@range ? 12 : 4)
    @size        = (File.size(@filename) - 5) / (@record_size)
  end
end

Instance Attribute Details

#file ⇒ Object

Returns the value of attribute file.



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# File 'lib/rbbt/fix_width_table.rb', line 3

def file
  @file
end

#filename ⇒ Object

Returns the value of attribute filename.



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# File 'lib/rbbt/fix_width_table.rb', line 3

def filename
  @filename
end

#range ⇒ Object

Returns the value of attribute range.



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# File 'lib/rbbt/fix_width_table.rb', line 3

def range
  @range
end

#record_size ⇒ Object

Returns the value of attribute record_size.



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# File 'lib/rbbt/fix_width_table.rb', line 3

def record_size
  @record_size
end

#size ⇒ Object

Returns the value of attribute size.



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# File 'lib/rbbt/fix_width_table.rb', line 3

def size
  @size
end

#value_size ⇒ Object

Returns the value of attribute value_size.



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# File 'lib/rbbt/fix_width_table.rb', line 3

def value_size
  @value_size
end

Class Method Details

.get(filename, value_size = nil, range = nil, update = false) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 40

def self.get(filename, value_size = nil, range = nil, update = false)
  return self.new(filename, value_size, range, update) if filename == :memory
  case
  when (!File.exists?(filename) or update or not CONNECTIONS.include?(filename))
    CONNECTIONS[filename] = self.new(filename, value_size, range, update)
  end

  CONNECTIONS[filename] 
end

Instance Method Details

#[](pos) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 237

def [](pos)
  return [] if size == 0
  if range
    get_range(pos)
  else
    get_point(pos)
  end
end

#add(pos, value) ⇒ Object Also known as: << 



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# File 'lib/rbbt/fix_width_table.rb', line 69

def add(pos, value)
  format = format(pos, value)
  @file.write format
  @size += 1
end

#add_point(data) ⇒ Object

{{{ Adding data



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# File 'lib/rbbt/fix_width_table.rb', line 122

def add_point(data)
  data.sort_by{|value, pos| pos }.each do |value, pos|
    add pos, value
  end
end

#add_range(data) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 128

def add_range(data)
  latest = []
  data.sort_by{|value, pos| pos[0] }.each do |value, pos|
    while latest.any? and latest[0] < pos[0]
      latest.shift
    end

    overlap = latest.length

    add pos + [overlap], value
    latest << pos[1]
  end
end

#chunked_values_at(keys, max = 5000) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 252

def chunked_values_at(keys, max = 5000)
  Misc.ordered_divide(keys, max).inject([]) do |acc,c|
    new = self.values_at(*c)
    new.annotate acc if new.respond_to? :annotate and acc.empty?
    acc.concat(new)
  end
end

#close ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 110

def close
  @file.close
end

#closest(pos) ⇒ Object

{{{ Searching



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# File 'lib/rbbt/fix_width_table.rb', line 144

def closest(pos)
  upper = size - 1
  lower = 0

  return -1 if upper < lower

  while(upper >= lower) do
    idx = lower + (upper - lower) / 2
    pos_idx = pos(idx)

    case pos <=> pos_idx
    when 0
      break
    when -1
      upper = idx - 1
    when 1
      lower = idx + 1
    end
  end

  if pos_idx > pos
    idx = idx - 1
  end

  idx.to_i
end

#dump ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 114

def dump
  read
  @file.rewind
  @file.read
end

#format(pos, value) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 50

def format(pos, value)
  padding = value_size - value.length
  if range
    (pos  + [value + ("\0" * padding)]).pack("llla#{value_size}")
  else
    [pos, value + ("\0" * padding)].pack("la#{value_size}")
  end
end

#get_point(pos) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 203

def get_point(pos)
  if Range === pos
    r_start = pos.begin
    r_end   = pos.end
  else
    r_start = pos.to_i
    r_end   = pos.to_i
  end

  idx = closest(r_start)

  return [] if idx >= size
  return [] if idx <0 and r_start == r_end

  idx = 0 if idx < 0

  idx += 1 unless pos(idx) >= r_start

  return [] if idx >= size

  values = []
  l_start = pos(idx)
  l_end   = pos_end(idx)
  while l_start <= r_end
    values << value(idx)
    idx += 1
    break if idx >= size
    l_start = pos(idx)
    l_end   = pos_end(idx)
  end

  values
end

#get_range(pos) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 171

def get_range(pos)
  if Range === pos
    r_start = pos.begin
    r_end   = pos.end
  else
    r_start = pos.to_i
    r_end   = pos.to_i
  end

  idx = closest(r_start)

  return [] if idx >= size
  return [] if idx <0 and r_start == r_end

  idx = 0 if idx < 0

  idx -= overlap(idx) unless overlap(idx).nil?

  values = []
  l_start = pos(idx)
  l_end   = pos_end(idx)
  while l_start <= r_end
    values << value(idx) if l_end >= r_start 
    idx += 1
    break if idx >= size
    l_start = pos(idx)
    l_end   = pos_end(idx)
  end

  values
end

#last_pos ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 76

def last_pos
  pos(size - 1)
end

#overlap(index) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 92

def overlap(index)
  return nil if index < 0 or index >= size
  @file.seek(13 + (record_size) * index, IO::SEEK_SET)
  @file.read(4).unpack("l").first
end

#pos(index) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 80

def pos(index)
  return nil if index < 0 or index >= size
  @file.seek(5 + (record_size) * index, IO::SEEK_SET)
  @file.read(4).unpack("l").first
end

#pos_end(index) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 86

def pos_end(index)
  return nil if index < 0 or index >= size
  @file.seek(9 + (record_size) * index, IO::SEEK_SET)
  @file.read(4).unpack("l").first
end

#read ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 104

def read
  return if @filename == :memory
  @file.close unless @file.closed?
  @file = File.open(@filename, 'r')
end

#unformat(format) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 59

def unformat(format)
  if range
    pos_start, pos_end, pos_overlap, value = format.unpack("llla#{value_size}")
    [[pos_start, pos_end, pos_overlap], value.strip]
  else
    pos, value = format.unpack("la#{value_size}")
    [pos, value.strip]
  end
end

#value(index) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 98

def value(index)
  return nil if index < 0 or index >= size
  @file.seek((range ? 17 : 9 ) + (record_size) * index, IO::SEEK_SET)
  @file.read(value_size).unpack("a#{value_size}").first.strip
end

#values_at(*list) ⇒ Object 



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# File 'lib/rbbt/fix_width_table.rb', line 246

def values_at(*list)
  list.collect{|pos|
    self[pos]
  }
end