Class: Webmidi::SMF::Reader::StringStream

Inherits:
Object
  • Object
show all
Defined in:
lib/webmidi/smf/reader.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(data) ⇒ StringStream

Returns a new instance of StringStream.



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# File 'lib/webmidi/smf/reader.rb', line 150

def initialize(data)
  @data = data
  @position = 0
end

Instance Attribute Details

#position ⇒ Object (readonly)

Returns the value of attribute position.



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# File 'lib/webmidi/smf/reader.rb', line 148

def position
  @position
end

Instance Method Details

#peek_byte ⇒ Object 



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# File 'lib/webmidi/smf/reader.rb', line 176

def peek_byte
  ensure_available!(1)
  @data.getbyte(@position)
end

#read_byte ⇒ Object 



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# File 'lib/webmidi/smf/reader.rb', line 169

def read_byte
  ensure_available!(1)
  byte = @data.getbyte(@position)
  @position += 1
  byte
end

#read_bytes(n) ⇒ Object 



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# File 'lib/webmidi/smf/reader.rb', line 155

def read_bytes(n)
  ensure_available!(n)
  result = @data[@position, n]
  @position += n
  result
end

#read_raw_bytes(n) ⇒ Object 



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# File 'lib/webmidi/smf/reader.rb', line 162

def read_raw_bytes(n)
  ensure_available!(n)
  result = @data[@position, n].bytes
  @position += n
  result
end

#read_uint16 ⇒ Object 



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# File 'lib/webmidi/smf/reader.rb', line 194

def read_uint16
  ensure_available!(2)
  val = (@data.getbyte(@position) << 8) | @data.getbyte(@position + 1)
  @position += 2
  val
end

#read_uint32 ⇒ Object 



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# File 'lib/webmidi/smf/reader.rb', line 201

def read_uint32
  ensure_available!(4)
  val = (@data.getbyte(@position) << 24) |
    (@data.getbyte(@position + 1) << 16) |
    (@data.getbyte(@position + 2) << 8) |
    @data.getbyte(@position + 3)
  @position += 4
  val
end

#read_vlq ⇒ Object

Raises:



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# File 'lib/webmidi/smf/reader.rb', line 211

def read_vlq
  value = 0
  4.times do
    byte = read_byte
    value = (value << 7) | (byte & 0x7F)
    return value unless (byte & 0x80) != 0
  end

  raise InvalidSMFError, "VLQ exceeds 4 bytes"
end

#skip(n) ⇒ Object 



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# File 'lib/webmidi/smf/reader.rb', line 181

def skip(n)
  ensure_available!(n)
  @position += n
end

#with_limit(limit) ⇒ Object 



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# File 'lib/webmidi/smf/reader.rb', line 186

def with_limit(limit)
  @limits ||= []
  @limits.push(limit)
  yield
ensure
  @limits.pop
end