module DiscId

Return the name of the default disc drive for this operating system.

@return [String] An operating system dependent device identifier

# File lib/discid.rb, line 149
def self.default_device
  Lib.default_device
end

A list of features supported by the current platform.

Currently the following features are available:

• :read

• :mcn

• :isrc

@note libdiscid >= 0.5.0 required. Older versions will return only [:read].

@return [Array<Symbol>]

# File lib/discid.rb, line 178
def self.feature_list
  return Lib::Features.symbols.select {|f| Lib.has_feature(f) == 1}
end

Check if a certain feature is implemented on the current platform.

You can obtain a list of supported features with {feature_list}.

@note libdiscid >= 0.5.0 required. Older versions will return `true`

for `:read` and `false` for anything else.

@param feature [:read, :mcn, :isrc] @return [Boolean] True if the feature is implemented and false if not.

# File lib/discid.rb, line 162
def self.has_feature?(feature)
  feature = feature.to_sym if feature.respond_to? :to_sym
  return self.feature_list.include? feature
end

Parses a TOC string and returns a [Disc] instance for it.

This function can be used if you already have a TOC string like e.g. `1 11 242457 150 44942 61305 72755 96360 130485 147315 164275 190702 205412 220437`

@raise [DiscError] The TOC string was invalid and could not be parsed. @param toc [String] A TOC string in the format `1 11 242457 150 44942 61305 72755 96360 130485 147315 164275 190702 205412 220437`. @return [Disc]

# File lib/discid.rb, line 131
def self.parse(toc)
  if toc.nil? || toc.empty?
    raise DiscError, "Invalid TOC #{toc.inspect}"
  end
  begin
    parts = toc.split(' ')
    first_track = Integer(parts[0])
    sectors = Integer(parts[2])
    offsets = parts[3..-1].map{|i| Integer(i)}
  rescue ArgumentError, TypeError => e
    raise DiscError, e
  end
  return self.put(first_track, sectors, offsets)
end

Provides the TOC of a known CD.

This function may be used if the TOC has been read earlier and you want to calculate the disc ID afterwards, without accessing the disc drive.

@raise [DiscError] The TOC could not be set. `Exception#message`contains

error details.

@param first_track [Integer] The number of the first audio track on the

disc (usually one).

@param sectors [Integer] The total number of sectors on the disc. @param offsets [Array] An array with track offsets (sectors) for each track. @return [Disc]

# File lib/discid.rb, line 117
def self.put(first_track, sectors, offsets)
  disc = Disc.new
  disc.put first_track, sectors, offsets
  return disc
end

Read the disc in the given CD-ROM/DVD-ROM drive extracting only the TOC and additionally specified features.

This function reads the disc in the drive specified by the given device identifier. If the device is `nil`, the default device, as returned by {default_device}, is used.

This function will always read the TOC, but additional features like `:mcn` and `:isrc` can be set using the features parameter. You can set multiple features.

@example Read only the TOC:

disc = DiscId.read(device)

@example Read the TOC, MCN and ISRCs:

disc = DiscId.read(device, :mcn, :isrc)

@note libdiscid >= 0.5.0 is required for the feature selection to work.

Older versions will allways read MCN and ISRCs when supported. See
{http://musicbrainz.org/doc/libdiscid#Feature_Matrix} for a list of
supported features by version and platform.

@raise [TypeError] `device` can not be converted to a String. @raise [DiscError] Error reading from `device`. `Exception#message` contains

error details.

@param device [String] The device identifier. If set to `nil` {default_device}

will be used.

@param features [:mcn, :isrc] List of features to use.

`:read` is always implied.

@return [Disc]

# File lib/discid.rb, line 99
def self.read(device = nil, *features)
  disc = Disc.new
  disc.read device, *features
  return disc
end

Converts sectors to seconds.

According to the red book standard 75 sectors are one second.

@private @param sectors [Integer] Number of sectors @return [Integer] The seconds

# File lib/discid.rb, line 189
def self.sectors_to_seconds(sectors)
  return (sectors.to_f / 75).truncate
end