Class: Pocolog::BlockStream::StreamBlock

Inherits:
Object
  • Object
show all
Defined in:
lib/pocolog/block_stream.rb

Overview

Information about a stream declaration block

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, typename, registry_xml, metadata_yaml) ⇒ StreamBlock

Returns a new instance of StreamBlock.



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# File 'lib/pocolog/block_stream.rb', line 267

def initialize(name, typename, registry_xml, metadata_yaml)
    @name = name
    @typename = typename
    @registry_xml = registry_xml
    @metadata_yaml = metadata_yaml

    @type = nil
    @metadata = nil
end

Instance Attribute Details

#metadata_yaml ⇒ Object (readonly)

Returns the value of attribute metadata_yaml.



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# File 'lib/pocolog/block_stream.rb', line 227

def metadata_yaml
  @metadata_yaml
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/pocolog/block_stream.rb', line 224

def name
  @name
end

#registry_xml ⇒ Object (readonly)

Returns the value of attribute registry_xml.



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# File 'lib/pocolog/block_stream.rb', line 226

def registry_xml
  @registry_xml
end

#typename ⇒ Object (readonly)

Returns the value of attribute typename.



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# File 'lib/pocolog/block_stream.rb', line 225

def typename
  @typename
end

Class Method Details

.parse(raw_data) ⇒ Object 



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# File 'lib/pocolog/block_stream.rb', line 243

def self.parse(raw_data)
    name, offset     = read_string(raw_data, 1)
    typename, offset = read_string(raw_data, offset)

    if raw_data.size > offset
        registry_xml, offset = read_string(raw_data, offset)
    else
        registry_xml = "<?xml version='1.0'?>\n<typelib></typelib>"
    end

    if raw_data.size > offset
        metadata_yaml, offset = read_string(raw_data, offset)
    else
        metadata_yaml = "--- {}\n"
    end
    if offset != raw_data.size
        raise InvalidBlockFound,
              "#{raw_data.size - offset} bytes unclaimed in "\
              'stream declaration block'
    end

    new(name, typename, registry_xml, metadata_yaml)
end

.read(raw_data, offset, count) ⇒ Object 



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# File 'lib/pocolog/block_stream.rb', line 229

def self.read(raw_data, offset, count)
    if raw_data.size < offset + count
        raise NotEnoughData,
              'expected stream block header to be at least of size '\
              "#{offset + count}, but got only #{raw_data.size}"
    end
    raw_data[offset, count]
end

.read_string(raw_data, offset) ⇒ Object 



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# File 'lib/pocolog/block_stream.rb', line 238

def self.read_string(raw_data, offset)
    size = read(raw_data, offset, 4).unpack('V').first
    [read(raw_data, offset + 4, size), (offset + 4 + size)]
end

Instance Method Details

#encode ⇒ Object

Return the encoded (on-disk) representation of this stream definition



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# File 'lib/pocolog/block_stream.rb', line 291

def encode # rubocop:disable Metrics/AbcSize
    [
        DATA_STREAM, name.size, name,
        typename.size, typename,
        registry_xml.size, registry_xml,
        metadata_yaml.size, metadata_yaml
    ].pack("CVa#{name.size}Va#{typename.size}"\
           "Va#{registry_xml.size}Va#{metadata_yaml.size}")
end

#metadata ⇒ Object 



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# File 'lib/pocolog/block_stream.rb', line 286

def metadata
    @metadata ||= YAML.safe_load(metadata_yaml)
end

#type ⇒ Object 



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# File 'lib/pocolog/block_stream.rb', line 277

def type
    if @type
        @type
    else
        registry = Typelib::Registry.from_xml(registry_xml)
        @type = registry.build(typename)
    end
end