Module: MemoryIO::Util

Defined in:
lib/memory_io/util.rb

Overview

Defines utility methods.

Defined Under Namespace

Classes: FilePermission

Class Method Summary collapse

Class Method Details

.file_permission(file) ⇒ MemoryIO::Util::FilePermission?

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns nil is returned if file does not exist or is inaccessible.

Parameters:

  • file (String) —

    File name.

Returns:



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# File 'lib/memory_io/util.rb', line 68

def file_permission(file)
  return nil unless File.file?(file)

  FilePermission.new(file)
end

.pack(val, b) ⇒ String

Pack an integer into b bytes. Little endian is used.

Examples:

Util.pack(0x123, 4)
#=> "\x23\x01\x00\x00"

Parameters:

  • val (Integer) —

    The integer to pack. If val contains more than b bytes, only lower b bytes in val will be packed.

  • b (Integer)

Returns:

  • (String) —

    Packing result with length b.



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# File 'lib/memory_io/util.rb', line 129

def pack(val, b)
  Array.new(b) { |i| (val >> (i * 8)) & 0xff }.pack('C*')
end

.safe_eval(str, **vars) ⇒ Integer

Evaluate string safely.

Examples:

Util.safe_eval('heap + 0x10 * pp', heap: 0xde00, pp: 8)
#=> 56960 # 0xde80

Parameters:

  • str (String) —

    String to be evaluated.

  • vars ({Symbol => Integer}) —

    Predefined variables

Returns:

  • (Integer) —

    Result.



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# File 'lib/memory_io/util.rb', line 87

def safe_eval(str, **vars)
  return str if str.is_a?(Integer)

  # dentaku 2 doesn't support hex
  str = str.gsub(/0x[0-9a-zA-Z]+/) { |c| c.to_i(16) }
  Dentaku::Calculator.new.store(vars).evaluate(str)
end

.trim_libname(name) ⇒ String

Remove extension name (.so) and version in library name.

Examples:

Util.trim_libname('libc-2.24.so')
#=> 'libc'
Util.trim_libname('libcrypto.so.1.0.0')
#=> 'libcrypto'
Util.trim_libname('not_a_so')
#=> 'not_a_so'
Util.trim_libname('ld-linux-x86-64.so.2')
#=> 'ld'

Parameters:

  • name (String) —

    Original library filename.

Returns:

  • (String) —

    Name without version and ‘.so’.



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# File 'lib/memory_io/util.rb', line 150

def trim_libname(name)
  return 'ld' if name.start_with?('ld-')

  type1 = '(-[\d.]+)?\.so$'
  type2 = '\.so.[\.\d]+$'
  name.sub(/#{type1}|#{type2}/, '')
end

.underscore(str) ⇒ String

Convert input into snake-case.

This method also converts ‘::’ to ‘/’.

Examples:

Util.underscore('MemoryIO')
#=> 'memory_io'

Util.underscore('MyModule::MyClass')
#=> 'my_module/my_class'

Parameters:

  • str (String) —

    String to be converted.

Returns:

  • (String) —

    Converted string.



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# File 'lib/memory_io/util.rb', line 51

def underscore(str)
  return '' if str.empty?

  str = str.gsub('::', '/')
  str.gsub!(/([A-Z]+)([A-Z][a-z])/, '\1_\2')
  str.gsub!(/([a-z\d])([A-Z])/, '\1_\2')
  str.downcase!
  str
end

.unpack(str) ⇒ Integer

Unpack a string into an integer. Little endian is used.

Examples:

Util.unpack("\xff")
#=> 255
Util.unpack("@\xE2\x01\x00")
#=> 123456

Parameters:

  • str (String) —

    String.

Returns:

  • (Integer) —

    Result.



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# File 'lib/memory_io/util.rb', line 109

def unpack(str)
  str.bytes.reverse.reduce(0) { |s, c| (s * 256) + c }
end