Class: ELFTools::LazyArray

Inherits:

SimpleDelegator

• Object
• SimpleDelegator
• ELFTools::LazyArray

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

• #[](i) ⇒ Object

  To access elements like a normal array.

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

  Instantiate a LazyArray object.

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.

[View on GitHub]

# File 'lib/elftools/lazy_array.rb', line 30

def initialize(size, &block)
  super(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.

[View on GitHub]

# File 'lib/elftools/lazy_array.rb', line 42

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

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