Class: OggAlbumTagger::TagContainer

Inherits:
Object
  • Object
show all
Defined in:
lib/ogg_album_tagger/tag_container.rb

Overview

A TagContainer is basically a hashmap associating a name to a set of string values.

The keys of the hashmap (aka the tags) are case insensitive (they are stored upcase). A tag cannot be an empty string or containe the “=” or “~” characters. Tags with no values are automatically removed.

Direct Known Subclasses

OggFile

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(tags = {}) ⇒ TagContainer

Allow to build a TagContainer using the following syntax:

t = TagContainer.new artist: "Alice", genre: %w{Pop Rock}, tracknumber: 1, ... The values associated to a tag are automatically casted to a String. Single values are treated as an array of one value.



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# File 'lib/ogg_album_tagger/tag_container.rb', line 18

def initialize tags = {}
    @hash = Hash.new

    tags.each { |tag, values|
        next if values.nil?

        values = [values] unless values.is_a?(Array) or values.is_a?(Set)

        next if values.empty?

        prepare_tag(tag.to_s.upcase)
        values.each { |value| @hash[tag.to_s.upcase].add(value.to_s) }
    }
end

Class Method Details

.pp_tag(values) ⇒ Object

Pretty print an array of values.



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# File 'lib/ogg_album_tagger/tag_container.rb', line 114

def self.pp_tag values
    values_str = values.map { |v| v.to_s.length > 64 ? (v.to_s.slice(0, 64) + '...') : v }

    case values.length
    when 0 then '- (empty)'
    when 1 then values_str[0]
    else sprintf("(%d) [%s]", values.length, values_str.join(', '))
    end
end

.valid_tag?(tag) ⇒ Boolean

Check if the tag is valid, otherwise raise an ArgumentError. Valid tags are composed of any character from “ ” to “}”, excluding “=” and “~”.

Returns:

  • (Boolean)

Raises:



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# File 'lib/ogg_album_tagger/tag_container.rb', line 56

def self.valid_tag? tag
    raise ArgumentError, "Invalid tag." unless tag =~ /^[\x20-\x3C\x3E-\x7D]+$/
end

Instance Method Details

#[](tag) ⇒ Object

Returns a Set containing the values associated to the specified tag.

If the tag does not exists, returns an empty Set. Do not use the returned Set to add new tags, use the methods provided by the class.



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# File 'lib/ogg_album_tagger/tag_container.rb', line 37

def [](tag)
    has_tag?(tag) ? @hash[tag.upcase] : Set.new.freeze
end

#add_values(tag, *values) ⇒ Object

Add some values to the specified tag.



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# File 'lib/ogg_album_tagger/tag_container.rb', line 80

def add_values(tag, *values)
    return if values.empty?

    prepare_tag tag
    @hash[tag.upcase].merge(values)

    self
end

#each ⇒ Object

 Iterate through the available tags.



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# File 'lib/ogg_album_tagger/tag_container.rb', line 109

def each
    @hash.each { |tag, set| yield(tag, set) }
end

#first(tag) ⇒ Object 



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# File 'lib/ogg_album_tagger/tag_container.rb', line 41

def first(tag)
    if has_tag?(tag)
        return @hash[tag.upcase].first
    else
        raise IndexError, "Tag \"#{tag}\" does not exists."
    end
end

#has_tag?(tag) ⇒ Boolean

Check if the specified tag is present in the container.

Returns:

  • (Boolean) 


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# File 'lib/ogg_album_tagger/tag_container.rb', line 50

def has_tag? tag
    @hash.has_key?(tag.upcase)
end

#rm_values(tag, *values) ⇒ Object

Remove some tags. If no value is specified, the specified tag is removed.



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# File 'lib/ogg_album_tagger/tag_container.rb', line 90

def rm_values(tag, *values)
    TagContainer::valid_tag? tag

    if values.empty?
        @hash.delete(tag.upcase)
    else
        @hash[tag.upcase].subtract(values)
        @hash.delete(tag.upcase) if @hash[tag.upcase].empty?
    end

    self
end

#set_values(tag, *values) ⇒ Object

Add some values to the specified tag. Any previous values will be removed.



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# File 'lib/ogg_album_tagger/tag_container.rb', line 68

def set_values(tag, *values)
    if values.empty?
        rm_values(tag)
    else
        prepare_tag tag
        @hash[tag.upcase].replace(values)
    end

    self
end

#tags ⇒ Object

Returns the list of present tags.



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# File 'lib/ogg_album_tagger/tag_container.rb', line 104

def tags
    @hash.keys
end