Class: GuitarProParser::InputStream

Inherits:
Object
  • Object
show all
Defined in:
lib/guitar_pro_parser/io/input_stream.rb

Constant Summary collapse

INTEGER_LENGTH = 
4
SHORT_INTEGER_LENGTH = 
2
BYTE_LENGTH = 
1

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(file_path) ⇒ InputStream

Returns a new instance of InputStream.



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 11

def initialize file_path
  @file_path = file_path
  @offset = 0
end

Instance Attribute Details

#offset ⇒ Object

Returns the value of attribute offset.



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 9

def offset
  @offset
end

Instance Method Details

#increment_offset(delta) ⇒ Object 



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 92

def increment_offset delta
  @offset = @offset + delta
end

#read_bitmask ⇒ Object

Reads byte as 8-bit bitmask



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 71

def read_bitmask
  bits = []
  value = read_byte
  value.to_s(2).each_char { |bit| bits << !bit.to_i.zero? }
  bits.reverse!
  bits << false while bits.count < 8
  bits
end

#read_boolean ⇒ Object

Reads signed byte as boolean (8 bit)



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 59

def read_boolean
  !read_byte.zero?
end

#read_byte ⇒ Object

Reads unsigned byte (8 bits) (0..255)



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 45

def read_byte
  value = IO.binread(@file_path, BYTE_LENGTH, @offset).unpack('C')[0]
  skip_byte
  value
end

#read_chunk ⇒ Object

Reads data chunk from file.

Chunk’s format is: 4 bytes - field length (including string length byte that follows this value) 1 byte - string length (N) N bytes - string



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 86

def read_chunk
  skip_integer
  string_length = read_byte
  read_string string_length
end

#read_integer ⇒ Object

Reads unsigned integer (4 bytes)



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 17

def read_integer
  value = IO.binread(@file_path, INTEGER_LENGTH, @offset).unpack('i')[0]
  skip_integer
  value
end

#read_short_integer ⇒ Object

Reads unsigned short integer (2 bytes)



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 31

def read_short_integer
  value = IO.binread(@file_path, SHORT_INTEGER_LENGTH, @offset).unpack('S_')[0]
  skip_short_integer
  value
end

#read_signed_byte ⇒ Object

Reads signed byte (8 bits) (-127..127)



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 52

def read_signed_byte
  value = IO.binread(@file_path, BYTE_LENGTH, @offset).unpack('c')[0]
  skip_byte
  value
end

#read_signed_integer ⇒ Object

Reads signed integer (4 bytes)



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 24

def read_signed_integer
  value = IO.binread(@file_path, INTEGER_LENGTH, @offset).unpack('I')[0]
  skip_integer
  value
end

#read_signed_short_integer ⇒ Object

Reads signed short integer (2 bytes)



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 38

def read_signed_short_integer
  value = IO.binread(@file_path, SHORT_INTEGER_LENGTH, @offset).unpack('s_')[0]
  skip_short_integer
  value
end

#read_string(length) ⇒ Object

Reads string with specified length



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 64

def read_string(length)
  value = IO.binread(@file_path, length, @offset)
  increment_offset(length)
  value
end

#skip_byte ⇒ Object 



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 104

def skip_byte
  increment_offset(BYTE_LENGTH)
end

#skip_integer ⇒ Object 



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 96

def skip_integer
  increment_offset(INTEGER_LENGTH)
end

#skip_short_integer ⇒ Object 



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# File 'lib/guitar_pro_parser/io/input_stream.rb', line 100

def skip_short_integer
  increment_offset(SHORT_INTEGER_LENGTH)
end