Class: VCD::Reader

Inherits:
Object
  • Object
show all
Defined in:
lib/libfst/vcd.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(io) ⇒ Reader

Returns a new instance of Reader.

Parameters:

  • io (String, IO) —

    either a file name or an opened IO.



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# File 'lib/libfst/vcd.rb', line 137

def initialize(io)
  @io_is_file = false
  if io.is_a?(String) then
    @io_is_file = true
    @io = File.open(io)
  else
    @io = io
  end
  @buf = []
  @root = Scope.new('root', :module, nil)
  @scope_stack = [@root]
  @state = :process_definitions
  @comments = []
  @stop_parsing = false
  @io.each_line do |line|
    process_line(line.chomp)
    break if @stop_parsing
  end
  if @io_is_file then
    @io.close 
    @io = io
  end

  remove_instance_variable :@stop_parsing
  remove_instance_variable :@state
  remove_instance_variable :@buf
  remove_instance_variable :@scope_stack

  @on_comment = nil
  @on_time_change = nil
end

Instance Attribute Details

#comments ⇒ Array<String> (readonly)

Returns:

  • (Array<String>) 


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# File 'lib/libfst/vcd.rb', line 130

def comments
  @comments
end

#date ⇒ String? (readonly)

Returns:

  • (String, nil) 


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# File 'lib/libfst/vcd.rb', line 128

def date
  @date
end

#root ⇒ Scope (readonly)

Returns:



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# File 'lib/libfst/vcd.rb', line 132

def root
  @root
end

#timescale ⇒ Float (readonly)

Returns:

  • (Float) 


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# File 'lib/libfst/vcd.rb', line 131

def timescale
  @timescale
end

#traces ⇒ Hash{String => Trace} (readonly)

Returns Traces stored by ID.

Returns:

  • (Hash{String => Trace}) —

    Traces stored by ID



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# File 'lib/libfst/vcd.rb', line 133

def traces
  @traces
end

#version ⇒ String? (readonly)

Returns:

  • (String, nil) 


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# File 'lib/libfst/vcd.rb', line 129

def version
  @version
end

Instance Method Details

#[](path) ⇒ Scope, ...

Returns the scope or variable corresponding to the specified path

Parameters:

  • path (String)

Returns:

Raises:

  • (ArgumentError) 


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# File 'lib/libfst/vcd.rb', line 186

def [](path)
  return @root if path == '/'
  raise ArgumentError, "expecting a String, not a #{path.class}" unless path.is_a?(String)
  a = path.split('/').reject(&:empty?)
  return nil if a.empty?
  scope = @root
  var = nil
  a.each do |w|
    var = scope.variables.select{ |v| v.name == w }.first
    return var if var
    s = scope.children.select{ |v| v.name == w }.first
    return nil if s.nil?
    scope = s
  end
  scope
end

#on_comment {|comment, time, vcd| ... } ⇒ self

Set the block of code to be executed when a comment is found while reading the value change section of the file

Yield Parameters:

  • comment (String)
  • time (Integer) —

    this integer is to be multiplied with #timescale the get the real time

  • vcd (self)

Returns:

  • (self) 


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# File 'lib/libfst/vcd.rb', line 209

def on_comment(&block)
  @on_comment = block
  self
end

#on_time_change {|time, vcd| ... } ⇒ self

Set the block of code to be called when a time change is encountered.

Yield Parameters:

  • time (Integer) —

    this integer is to be multiplied with #timescale the get the real time

  • vcd (self)

Returns:

  • (self) 


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# File 'lib/libfst/vcd.rb', line 219

def on_time_change(&block)
  @on_time_change = block
  self
end

#pretty_time(t = nil) ⇒ String?

When called in one of the callbacks, returns the current time as a string, nil otherwise.

Parameters:

  • t (Integer, nil) (defaults to: nil)

Returns:

  • (String, nil) —

    example: "2.57 µs"



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# File 'lib/libfst/vcd.rb', line 329

def pretty_time(t = nil)
  t ||= @time
  return nil unless t
  return '0 s' if t == 0
  e = Math.log10(@timescale).round
  while (-e % 3) != 0 do
    t *= 10
    e -= 1
  end
  while e < -15 do
    t /= 10
    e += 1
  end

  while e < 0 and (t % 1000) == 0 do
    t /= 1000
    e += 3
  end

  ent = t
  qe = e
  mf = 1
  while qe < 0 and (ent / 1000) != 0 do
    ent /= 1000
    qe += 3
    mf *= 1000
  end

  rem = t - mf*ent
  while rem != 0 and (rem % 10) == 0 do
    rem /= 10
    e += 1
  end

  s = ent.to_s
  if rem != 0 then
    s += '.' + rem.to_s.rjust(qe - e, '0')
  end
  s += case qe
       when   0; ' s'
       when  -3; ' ms'
       when  -6; ' µs'
       when  -9; ' ns'
       when -12; ' ps'
       when -15; ' fs'
       else
         raise "unknown unit for exponent #{qe}"
       end
  s
end

#read(*signals, start_time: nil, end_time: nil) {|trace, value, time, vcd| ... } ⇒ self

Read the value change section of the VCD file.

Parameters:

  • signals (Trace, Variable, Scope, String) —

    if signals are specified, only those will trigger the block. A path can be provided as a string, which correspond to a Variable or a Scope. In the case of a Scope, all its variables will be added (NOT recursively).

  • start_time (Integer, Float, String, nil) (defaults to: nil) —

    start time from which to trigger the block

  • end_time (Integer, Float, String, nil) (defaults to: nil) —

    end time until which to trigger the block

Yield Parameters:

  • trace (Trace)
  • value (String, Float)
  • time (Integer) —

    this integer is to be multiplied with #timescale the get the real time

  • vcd (self)

Returns:

  • (self) 


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# File 'lib/libfst/vcd.rb', line 245

def read(*signals, start_time: nil, end_time: nil, &block)
  @time_win_start = nil
  @time_win_end = nil
  @trace_mask = nil

  @time_win_start = time_to_itime(start_time, false) if start_time
  @time_win_end   = time_to_itime(end_time,   true)  if end_time

  unless signals.empty? then
    @trace_mask = {}
    signals.each do |sig|
      if sig.is_a?(String) then
        s = self[sig] 
        raise "Cannot find #{sig.inspect} in the hierarchy" if s.nil?
        sig = s
      end
      case sig
      when Variable
        @trace_mask[sig.trace.id] = true
      when Trace
        @trace_mask[sig.id] = true
      when Scope
        sig.variables.each do |var|
          @trace_mask[var.trace.id] = true
        end
      else
        raise TypeError, "Expecting a path, a #{Variable}, a #{Trace} or a #{Scope}, not a #{sig.class}"
      end
    end
  end

  @on_read = block

  if @io_is_file then
    io = @io
    @io = File.open(io)
    @io.seek(@value_change_pos, IO::SEEK_SET)
  end

  @stop_parsing = false
  @state = nil
  @buf = nil
  @time = 0

  @io.each_line do |line|
    process_line(line.chomp)
    break if @stop_parsing
  end

  remove_instance_variable :@time_win_start
  remove_instance_variable :@time_win_end
  remove_instance_variable :@trace_mask
  remove_instance_variable :@on_read
  remove_instance_variable :@stop_parsing
  remove_instance_variable :@state
  remove_instance_variable :@buf

  if @io_is_file then
    @io.close 
    @io = io
  end

  @time = nil
end

#real_time ⇒ Float?

When called in one of the callbacks, returns the current time in seconds, nil otherwise.

Returns:

  • (Float, nil) 


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# File 'lib/libfst/vcd.rb', line 320

def real_time
  return nil unless @time
  @time*@timescale
end

#stop_parsing ⇒ self

Stop the parsing of the file. This method can be called from an #on_comment or #read block.

Returns:

  • (self) 


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# File 'lib/libfst/vcd.rb', line 228

def stop_parsing
  @stop_parsing = true
  self
end

#time ⇒ Integer?

When called in one of the callbacks, returns the current time as an integer, nil otherwise.

Returns:

  • (Integer, nil) —

    this value is to be multiplied with #timescale the get the real time



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# File 'lib/libfst/vcd.rb', line 313

def time
  @time
end

#to_s ⇒ String

Returns:

  • (String) 


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# File 'lib/libfst/vcd.rb', line 382

def to_s
  [
    "Date:      #{@date.inspect}",
    "Version:   #{@version.inspect}",
    "Timescale: #{@timescale}",
    "Comments:",
    @comments.collect{|s| "    " + s.inspect},
    @root.tree
  ].flatten.join("\n")
end

#variable(name) ⇒ Variable?

Find a Variable by its name or path

Parameters:

  • name (String) —

    name or path to look for

Returns:



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# File 'lib/libfst/vcd.rb', line 173

def variable(name)
  @traces.each_value do |t|
    t.variables.each do |v|
      return v if v.name == name or v.path == name
    end
  end
  nil
end