Current File : //opt/alt/ruby33/share/ruby/fiddle/struct.rb
# frozen_string_literal: true
require 'fiddle'
require 'fiddle/value'
require 'fiddle/pack'
module Fiddle
# A base class for objects representing a C structure
class CStruct
include Enumerable
# accessor to Fiddle::CStructEntity
def CStruct.entity_class
CStructEntity
end
def self.offsetof(name, members, types) # :nodoc:
offset = 0
worklist = name.split('.')
this_type = self
while search_name = worklist.shift
index = 0
member_index = members.index(search_name)
unless member_index
# Possibly a sub-structure
member_index = members.index { |member_name, _|
member_name == search_name
}
return unless member_index
end
types.each { |type, count = 1|
orig_offset = offset
if type.respond_to?(:entity_class)
align = type.alignment
type_size = type.size
else
align = PackInfo::ALIGN_MAP[type]
type_size = PackInfo::SIZE_MAP[type]
end
# Unions shouldn't advance the offset
if this_type.entity_class == CUnionEntity
type_size = 0
end
offset = PackInfo.align(orig_offset, align)
if worklist.empty?
return offset if index == member_index
else
if index == member_index
subtype = types[member_index]
members = subtype.members
types = subtype.types
this_type = subtype
break
end
end
offset += (type_size * count)
index += 1
}
end
nil
end
def each
return enum_for(__function__) unless block_given?
self.class.members.each do |name,|
yield(self[name])
end
end
def each_pair
return enum_for(__function__) unless block_given?
self.class.members.each do |name,|
yield(name, self[name])
end
end
def to_h
hash = {}
each_pair do |name, value|
hash[name] = unstruct(value)
end
hash
end
def replace(another)
if another.nil?
self.class.members.each do |name,|
self[name] = nil
end
elsif another.respond_to?(:each_pair)
another.each_pair do |name, value|
self[name] = value
end
else
another.each do |name, value|
self[name] = value
end
end
self
end
private
def unstruct(value)
case value
when CStruct
value.to_h
when Array
value.collect do |v|
unstruct(v)
end
else
value
end
end
end
# A base class for objects representing a C union
class CUnion
# accessor to Fiddle::CUnionEntity
def CUnion.entity_class
CUnionEntity
end
def self.offsetof(name, members, types) # :nodoc:
0
end
end
# Wrapper for arrays within a struct
class StructArray < Array
include ValueUtil
def initialize(ptr, type, initial_values)
@ptr = ptr
@type = type
@is_struct = @type.respond_to?(:entity_class)
if @is_struct
super(initial_values)
else
@size = Fiddle::PackInfo::SIZE_MAP[type]
@pack_format = Fiddle::PackInfo::PACK_MAP[type]
super(initial_values.collect { |v| unsigned_value(v, type) })
end
end
def to_ptr
@ptr
end
def []=(index, value)
if index < 0 || index >= size
raise IndexError, 'index %d outside of array bounds 0...%d' % [index, size]
end
if @is_struct
self[index].replace(value)
else
to_ptr[index * @size, @size] = [value].pack(@pack_format)
super(index, value)
end
end
end
# Used to construct C classes (CUnion, CStruct, etc)
#
# Fiddle::Importer#struct and Fiddle::Importer#union wrap this functionality in an
# easy-to-use manner.
module CStructBuilder
# Construct a new class given a C:
# * class +klass+ (CUnion, CStruct, or other that provide an
# #entity_class)
# * +types+ (Fiddle::TYPE_INT, Fiddle::TYPE_SIZE_T, etc., see the C types
# constants)
# * corresponding +members+
#
# Fiddle::Importer#struct and Fiddle::Importer#union wrap this functionality in an
# easy-to-use manner.
#
# Examples:
#
# require 'fiddle/struct'
# require 'fiddle/cparser'
#
# include Fiddle::CParser
#
# types, members = parse_struct_signature(['int i','char c'])
#
# MyStruct = Fiddle::CStructBuilder.create(Fiddle::CUnion, types, members)
#
# MyStruct.malloc(Fiddle::RUBY_FREE) do |obj|
# ...
# end
#
# obj = MyStruct.malloc(Fiddle::RUBY_FREE)
# begin
# ...
# ensure
# obj.call_free
# end
#
# obj = MyStruct.malloc
# begin
# ...
# ensure
# Fiddle.free obj.to_ptr
# end
#
def create(klass, types, members)
new_class = Class.new(klass){
define_method(:initialize){|addr, func = nil|
if addr.is_a?(self.class.entity_class)
@entity = addr
else
@entity = self.class.entity_class.new(addr, types, func)
end
@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 }
define_singleton_method(:types) { types }
define_singleton_method(:members) { members }
# Return the offset of a struct member given its name.
# For example:
#
# MyStruct = struct [
# "int64_t i",
# "char c",
# ]
#
# MyStruct.offsetof("i") # => 0
# MyStruct.offsetof("c") # => 8
#
define_singleton_method(:offsetof) { |name|
klass.offsetof(name, members, types)
}
members.each{|name|
name = name[0] if name.is_a?(Array) # name is a nested struct
next if method_defined?(name)
define_method(name){ @entity[name] }
define_method(name + "="){|val| @entity[name] = val }
}
entity_class = klass.entity_class
alignment = entity_class.alignment(types)
size = entity_class.size(types)
define_singleton_method(:alignment) { alignment }
define_singleton_method(:size) { size }
define_singleton_method(:malloc) do |func=nil, &block|
if block
entity_class.malloc(types, func, size) do |entity|
block.call(new(entity))
end
else
new(entity_class.malloc(types, func, size))
end
end
}
return new_class
end
module_function :create
end
# A pointer to a C structure
class CStructEntity < Fiddle::Pointer
include PackInfo
include ValueUtil
def CStructEntity.alignment(types)
max = 1
types.each do |type, count = 1|
if type.respond_to?(:entity_class)
n = type.alignment
else
n = ALIGN_MAP[type]
end
max = n if n > max
end
max
end
# Allocates a C struct with the +types+ provided.
#
# See Fiddle::Pointer.malloc for memory management issues.
def CStructEntity.malloc(types, func = nil, size = size(types), &block)
if block_given?
super(size, func) do |struct|
struct.set_ctypes types
yield struct
end
else
struct = super(size, func)
struct.set_ctypes types
struct
end
end
# Returns the offset for the packed sizes for the given +types+.
#
# Fiddle::CStructEntity.size(
# [ Fiddle::TYPE_DOUBLE,
# Fiddle::TYPE_INT,
# Fiddle::TYPE_CHAR,
# Fiddle::TYPE_VOIDP ]) #=> 24
def CStructEntity.size(types)
offset = 0
max_align = types.map { |type, count = 1|
last_offset = offset
if type.respond_to?(:entity_class)
align = type.alignment
type_size = type.size
else
align = PackInfo::ALIGN_MAP[type]
type_size = PackInfo::SIZE_MAP[type]
end
offset = PackInfo.align(last_offset, align) +
(type_size * count)
align
}.max
PackInfo.align(offset, max_align)
end
# Wraps the C pointer +addr+ as a C struct with the given +types+.
#
# When the instance is garbage collected, the C function +func+ is called.
#
# See also Fiddle::Pointer.new
def initialize(addr, types, func = nil)
if func && addr.is_a?(Pointer) && addr.free
raise ArgumentError, 'free function specified on both underlying struct Pointer and when creating a CStructEntity - who do you want to free this?'
end
set_ctypes(types)
super(addr, @size, func)
end
# Set the names of the +members+ in this C struct
def assign_names(members)
@members = []
@nested_structs = {}
members.each_with_index do |member, index|
if member.is_a?(Array) # nested struct
member_name = member[0]
struct_type, struct_count = @ctypes[index]
if struct_count.nil?
struct = struct_type.new(to_i + @offset[index])
else
structs = struct_count.times.map do |i|
struct_type.new(to_i + @offset[index] + i * struct_type.size)
end
struct = StructArray.new(to_i + @offset[index],
struct_type,
structs)
end
@nested_structs[member_name] = struct
else
member_name = member
end
@members << member_name
end
end
# Calculates the offsets and sizes for the given +types+ in the struct.
def set_ctypes(types)
@ctypes = types
@offset = []
offset = 0
max_align = types.map { |type, count = 1|
orig_offset = offset
if type.respond_to?(:entity_class)
align = type.alignment
type_size = type.size
else
align = ALIGN_MAP[type]
type_size = SIZE_MAP[type]
end
offset = PackInfo.align(orig_offset, align)
@offset << offset
offset += (type_size * count)
align
}.max
@size = PackInfo.align(offset, max_align)
end
# 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}")
end
ty = @ctypes[idx]
if( ty.is_a?(Array) )
if ty.first.respond_to?(:entity_class)
return @nested_structs[name]
else
r = super(@offset[idx], SIZE_MAP[ty[0]] * ty[1])
end
elsif ty.respond_to?(:entity_class)
return @nested_structs[name]
else
r = super(@offset[idx], SIZE_MAP[ty.abs])
end
packer = Packer.new([ty])
val = packer.unpack([r])
case ty
when Array
case ty[0]
when TYPE_VOIDP
val = val.collect{|v| Pointer.new(v)}
end
when TYPE_VOIDP
val = Pointer.new(val[0])
else
val = val[0]
end
if( ty.is_a?(Integer) && (ty < 0) )
return unsigned_value(val, ty)
elsif( ty.is_a?(Array) && (ty[0] < 0) )
return StructArray.new(self + @offset[idx], ty[0], val)
else
return val
end
end
# 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
name = name.to_s if name.is_a?(Symbol)
nested_struct = @nested_structs[name]
if nested_struct
if nested_struct.is_a?(StructArray)
if val.nil?
nested_struct.each do |s|
s.replace(nil)
end
else
val.each_with_index do |v, i|
nested_struct[i] = v
end
end
else
nested_struct.replace(val)
end
return val
end
idx = @members.index(name)
if( idx.nil? )
raise(ArgumentError, "no such member: #{name}")
end
ty = @ctypes[idx]
packer = Packer.new([ty])
val = wrap_arg(val, ty, [])
buff = packer.pack([val].flatten())
super(@offset[idx], buff.size, buff)
if( ty.is_a?(Integer) && (ty < 0) )
return unsigned_value(val, ty)
elsif( ty.is_a?(Array) && (ty[0] < 0) )
return val.collect{|v| unsigned_value(v,ty[0])}
else
return val
end
end
undef_method :size=
def to_s() # :nodoc:
super(@size)
end
end
# A pointer to a C union
class CUnionEntity < CStructEntity
include PackInfo
# Returns the size needed for the union with the given +types+.
#
# Fiddle::CUnionEntity.size(
# [ Fiddle::TYPE_DOUBLE,
# Fiddle::TYPE_INT,
# Fiddle::TYPE_CHAR,
# Fiddle::TYPE_VOIDP ]) #=> 8
def CUnionEntity.size(types)
types.map { |type, count = 1|
if type.respond_to?(:entity_class)
type.size * count
else
PackInfo::SIZE_MAP[type] * count
end
}.max
end
# Calculate the necessary offset and for each union member with the given
# +types+
def set_ctypes(types)
@ctypes = types
@offset = Array.new(types.length, 0)
@size = self.class.size types
end
end
end