[ruby/fiddle] Make array access override compatible with base class (#25)

* Allow access to a struct's underlying memory with `struct[offset, length]`.

* Make accessing a struct's underlying memory more convenient.

* refactor memory access unit tests for improved clarity


https://github.com/ruby/fiddle/commit/c082c81bb5
This commit is contained in:
sinisterchipmunk 2020-01-22 02:55:16 -05:00 коммит произвёл Nobuyoshi Nakada
Родитель aa1d3c7d2c
Коммит 4a835621ce
2 изменённых файлов: 53 добавлений и 4 удалений

Просмотреть файл

@ -54,6 +54,8 @@ module Fiddle
@entity = klass.entity_class.new(addr, types)
@entity.assign_names(members)
}
define_method(:[]) { |*args| @entity.send(:[], *args) }
define_method(:[]=) { |*args| @entity.send(:[]=, *args) }
define_method(:to_ptr){ @entity }
define_method(:to_i){ @entity.to_i }
members.each{|name|
@ -148,8 +150,21 @@ module Fiddle
@size = PackInfo.align(offset, max_align)
end
# Fetch struct member +name+
def [](name)
# Fetch struct member +name+ if only one argument is specified. If two
# arguments are specified, the first is an offset and the second is a
# length and this method returns the string of +length+ bytes beginning at
# +offset+.
#
# Examples:
#
# my_struct = struct(['int id']).malloc
# my_struct.id = 1
# my_struct['id'] # => 1
# my_struct[0, 4] # => "\x01\x00\x00\x00".b
#
def [](*args)
return super(*args) if args.size > 1
name = args[0]
idx = @members.index(name)
if( idx.nil? )
raise(ArgumentError, "no such member: #{name}")
@ -182,8 +197,20 @@ module Fiddle
end
end
# Set struct member +name+, to value +val+
def []=(name, val)
# Set struct member +name+, to value +val+. If more arguments are
# specified, writes the string of bytes to the memory at the given
# +offset+ and +length+.
#
# Examples:
#
# my_struct = struct(['int id']).malloc
# my_struct['id'] = 1
# my_struct[0, 4] = "\x01\x00\x00\x00".b
# my_struct.id # => 1
#
def []=(*args)
return super(*args) if args.size > 2
name, val = *args
idx = @members.index(name)
if( idx.nil? )
raise(ArgumentError, "no such member: #{name}")

Просмотреть файл

@ -54,6 +54,28 @@ module Fiddle
assert_match(/call dlload before/, err.message)
end
def test_struct_memory_access()
# check memory operations performed directly on struct
my_struct = Fiddle::Importer.struct(['int id']).malloc
my_struct[0, Fiddle::SIZEOF_INT] = "\x01".b * Fiddle::SIZEOF_INT
assert_equal 0x01010101, my_struct.id
my_struct.id = 0
assert_equal "\x00".b * Fiddle::SIZEOF_INT, my_struct[0, Fiddle::SIZEOF_INT]
end
def test_struct_ptr_array_subscript_multiarg()
# check memory operations performed on struct#to_ptr
struct = Fiddle::Importer.struct([ 'int x' ]).malloc
ptr = struct.to_ptr
struct.x = 0x02020202
assert_equal("\x02".b * Fiddle::SIZEOF_INT, ptr[0, Fiddle::SIZEOF_INT])
ptr[0, Fiddle::SIZEOF_INT] = "\x01".b * Fiddle::SIZEOF_INT
assert_equal 0x01010101, struct.x
end
def test_malloc()
s1 = LIBC::Timeval.malloc()
s2 = LIBC::Timeval.malloc()