Class: ELFTools::LazyArray

Inherits:
Object
  • Object
show all
Defined in:
lib/elftools/lazy_array.rb

Overview

A helper class for ELFTools easy to implement ‘lazy loading’ objects. Mainly used when loading sections, segments, and symbols.

Instance Method Summary collapse

Constructor Details

#initialize(size) {|i| ... } ⇒ LazyArray

Instantiate a ELFTools::LazyArray object.

Examples:

arr = LazyArray.new(10) { |i| p "calc #{i}"; i * i }
p arr[2]
# "calc 2"
# 4

p arr[3]
# "calc 3"
# 9

p arr[3]
# 9

Parameters:

  • size (Integer) —

    The size of array.

Yield Parameters:

  • i (Integer) —

    Needs the i-th element.

Yield Returns:

  • (Object) —

    Value of the i-th element.



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# File 'lib/elftools/lazy_array.rb', line 28

def initialize(size, &block)
  @internal = Array.new(size)
  @block = block
end

Instance Method Details

#[](i) ⇒ Object

To access elements like a normal array.

Elements are lazy loaded at the first time access it.

Returns:

  • (Object) —

    The element, returned type is the return type of block given in #initialize.



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# File 'lib/elftools/lazy_array.rb', line 40

def [](i)
  # XXX: support negative index?
  return nil unless i.between?(0, @internal.size - 1)

  @internal[i] ||= @block.call(i)
end