Module: XZ::FiddleHelper

Included in:
LibLZMA
Defined in:
lib/xz/fiddle_helper.rb

Overview

This is an internal API not meant for users of ruby-xz. This mixin modules defines some helper functions on top of Fiddle’s functionality.

Instance Method Summary collapse

Instance Method Details

#dlloadanyof(*names) ⇒ Object

Try loading any of the given names as a shared object. Raises Fiddle::DLError if none can be opened.

Raises:

  • (Fiddle::DLError) 


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# File 'lib/xz/fiddle_helper.rb', line 74

def dlloadanyof(*names)
  names.each do |name|
    begin
      dlload(name)
    rescue Fiddle::DLError
      # Continue with next one
    else
      # Success
      return name
    end
  end

  raise Fiddle::DLError, "Failed to open any of these shared object files: #{names.join(', ')}"
end

#enum(*args) ⇒ Object

Define constants that have numeric constants assigned as if it was a C enum definition. You can specificy values explicitely or rely on the implicit incrementation; the first implicit value is zero.

Example:

enum :FOO, :BAR, 5, :BAZ

This defines a constant FOO with value 0, BAR with value 5, BAZ with value 6.



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# File 'lib/xz/fiddle_helper.rb', line 46

def enum(*args)
  @next_enum_val = 0 # First value of an enum is 0 in C

  args.each_cons(2) do |val1, val2|
    next if val1.respond_to?(:to_int)

    if val2.respond_to?(:to_int)
      const_set(val1, val2.to_int)
      @next_enum_val = val2.to_int + 1
    else
      const_set(val1, @next_enum_val)
      @next_enum_val += 1
    end
  end

  # Cater for the last element in case it is not an explicit
  # value that has already been assigned above.
  unless args.last.respond_to?(:to_int)
    const_set(args.last, @next_enum_val)
  end

  @next_enum_val = 0
  nil
end