unpack binary encoded log files from SL into .csv for easy reading

read_sl_data.rb

#!/usr/bin/ruby
# Read SL log files
# hi@siri.sh
 
require 'csv'
 
@filename = "d00004"
 
 
@raw = File.open(@filename)
 
@num_of_data_points = nil
@num_of_variables = nil
@num_of_samples = nil
@sampling_rate = nil
@variables = nil
 
@values = []
 
### Get the plaintext headers ##########################
@raw.each_line do |line|
   
  # line number 2
  if @num_of_variables != nil and @variables == nil
    @variables = line.split
    0.upto(@num_of_variables.to_i-1) do |i|
      puts "#{@variables[2*i]} (#{@variables[2*i+1]})"
      eval "@#{@variables[2*i]} = Array.new"
    end
  end
   
  # line number 1
  @num_of_data_points ||= line.split[0]
  @num_of_variables ||= line.split[1]
  @num_of_samples ||= line.split[2]
  @sampling_rate ||= line.split[3]
   
end
 
puts "Number of variables: #{@num_of_variables}"
puts "Number of samples: #{@num_of_samples}"
puts "Sampling rate: #{@sampling_rate}"
 
 
### Get the binary encoded data ###########################
@raw = File.read(@filename)
#@floats = @raw[1388..-1]
@floats = @raw[-(@num_of_data_points.to_i*4)..-1]
puts @floats.length
 
index = 0
(0..@num_of_data_points.to_i-1).reverse_each do |i|
  #p -i*4-1
  #p @floats[-i*4-4..-i*4-1].unpack('g')
  #@values += @floats[-i*4-4..-i*4-1].unpack('f')
  #p @variables[2*(index%81)]
  eval "@#{@variables[2*(index % @num_of_variables.to_i)]} += @floats[-i*4-4..-i*4-1].unpack('g')" #if index%81 == 0
  index+=1
end
 
p @variables
p @values
p @time
#puts @values.length
 
 
### WRITE OUTPUT FILE ##############################
@out = CSV.open("#{@filename}.csv", "wb")
variable_list = []
0.upto(@num_of_variables.to_i-1) do |i|
  variable_list +=["#{@variables[2*i]} (#{@variables[2*i+1]})"]
end
p variable_list
@out << variable_list
 
0.upto(@num_of_samples.to_i-1) do |j|
  data_list = []
  0.upto(@num_of_variables.to_i-1) do |i|
    eval "data_list +=[@#{@variables[2*i]}[j]]"
  end
  @out << data_list
end
@out.close