Class: FFI::BitMasks::BitMask

Inherits:
Object
  • Object
show all
Includes:
DataConverter
Defined in:
lib/ffi/bit_masks/bit_mask.rb

Overview

The bitmask data converter.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(flags, type = :uint) ⇒ BitMask

Initializes a new bitmask.

Parameters:

  • flags (Hash{Symbol => Integer}) —

    The flags and their masks.

  • type (Symbol) (defaults to: :uint) —

    The underlying type.



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# File 'lib/ffi/bit_masks/bit_mask.rb', line 45

def initialize(flags,type=:uint)
  @flags       = flags
  @bitmasks    = flags.invert
  @native_type = FFI.find_type(type)
end

Instance Attribute Details

#bitmasks ⇒ Hash{Integer => Symbol} (readonly)

The masks of the bitmask.

Returns:

  • (Hash{Integer => Symbol}) —

    The mapping of bitmasks to bit-flags.



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# File 'lib/ffi/bit_masks/bit_mask.rb', line 26

def bitmasks
  @bitmasks
end

#flags ⇒ Hash{Symbol => Integer} (readonly)

Flags of the bitmask.

Returns:

  • (Hash{Symbol => Integer}) —

    The mapping of bit-flags to bitmasks.



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# File 'lib/ffi/bit_masks/bit_mask.rb', line 18

def flags
  @flags
end

#native_type ⇒ FFI::Type (readonly)

The underlying native type.

Returns:

  • (FFI::Type) —

    The FFI primitive.



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# File 'lib/ffi/bit_masks/bit_mask.rb', line 34

def native_type
  @native_type
end

Instance Method Details

#[](query) ⇒ Integer #[](query) ⇒ Symbol Also known as: find

Maps flags to masks and vice versa.

Overloads:

  • #[](query) ⇒ Integer

    Returns The mask for the flag.

    Parameters:

    • query (Symbol) —

      The flag name.

    Returns:

    • (Integer) —

      The mask for the flag.

  • #[](query) ⇒ Symbol

    Returns The flag for the mask.

    Parameters:

    • query (Integer) —

      The mask.

    Returns:

    • (Symbol) —

      The flag for the mask.



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# File 'lib/ffi/bit_masks/bit_mask.rb', line 104

def [](query)
  case query
  when Symbol  then @flags[query]
  when Integer then @bitmasks[query]
  end
end

#from_native(value, ctx = nil) ⇒ Hash{Symbol => Boolean}

Converts a bitmask into multiple flags.

Parameters:

  • value (Integer) —

    The raw bitmask.

Returns:

  • (Hash{Symbol => Boolean}) —

    The flags for the bitmask.



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# File 'lib/ffi/bit_masks/bit_mask.rb', line 175

def from_native(value,ctx=nil)
  flags = {}

  @flags.each do |flag,bitmask|
    flags[flag] ||= ((value & bitmask) == bitmask)
  end

  return flags
end

#symbol_map ⇒ Hash{Symbol => Integer} Also known as: to_h, to_hash

Note:

For compatibility with FFI::Enum.

The mapping of acceptable Symbols to their Integer equivalents.

Returns:

  • (Hash{Symbol => Integer}) —

    The mapping of Symbols.



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# File 'lib/ffi/bit_masks/bit_mask.rb', line 71

def symbol_map
  @flags
end

#symbols ⇒ Array<Symbol>

Note:

For compatibility with FFI::Enum.

The Symbols that can be passed to the data converter.

Returns:

  • (Array<Symbol>) —

    The Array of Symbols.



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# File 'lib/ffi/bit_masks/bit_mask.rb', line 59

def symbols
  @flags.keys
end

#to_native(value) ⇒ Integer #to_native(value) ⇒ Integer

Converts flags to a bitmask.

Overloads:

  • #to_native(value) ⇒ Integer

    Returns The bitmask for the given flags.

    Parameters:

    • value (Hash{Symbol => Boolean}) —

      The flags and their values.

    Returns:

    • (Integer) —

      The bitmask for the given flags.

  • #to_native(value) ⇒ Integer

    Returns The bitmask.

    Parameters:

    • value (#to_int) —

      The raw bitmask.

    Returns:

    • (Integer) —

      The bitmask.

Raises:

  • (ArgumentError) 


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# File 'lib/ffi/bit_masks/bit_mask.rb', line 137

def to_native(value,ctx=nil)
  uint = 0

  case value
  when Hash
    uint = 0

    value.each do |flag,value|
      if (@flags.has_key?(flag) && value)
        uint |= @flags[flag]
      end
    end

    return uint
  else
    if value.respond_to?(:to_int)
      int = value.to_int

      @bitmasks.each_key do |mask|
        uint |= (int & mask)
      end

      return uint
    else
      raise(ArgumentError,"invalid bitmask value #{value.inspect}")
    end
  end
end