* ext/fiddle/fiddle.c: adding alignment constants for compatibility

with DL.
* ext/fiddle/fiddle.h: ditto
* ext/fiddle/lib/fiddle/cparser.rb: importing the C parser for DL
  backwards compatibility.
* ext/fiddle/lib/fiddle/import.rb: importing the import DSL for DL
  backwards compatibility.
* ext/fiddle/lib/fiddle/pack.rb: importing structure pack for DL
  backwards compatibility.
* ext/fiddle/lib/fiddle/value.rb: ditto
* ext/fiddle/lib/fiddle/struct.rb: importing struct DSL for DL backwards
  compatibility.
* test/dl/test_c_struct_entry.rb: importing tests
* test/dl/test_c_union_entity.rb: ditto
* test/dl/test_cparser.rb: ditto
* test/dl/test_import.rb: ditto
* test/fiddle/test_c_struct_entry.rb: ditto
* test/fiddle/test_c_union_entity.rb: ditto
* test/fiddle/test_cparser.rb: ditto
* test/fiddle/test_import.rb: ditto

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@37914 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ext/fiddle/lib/fiddle/struct.rb

@@ -0,0 +1,236 @@
+require 'fiddle'
+require 'fiddle/value'
+require 'fiddle/pack'
+
+module Fiddle
+  # C struct shell
+  class CStruct
+    # accessor to Fiddle::CStructEntity
+    def CStruct.entity_class
+      CStructEntity
+    end
+  end
+
+  # C union shell
+  class CUnion
+    # accessor to Fiddle::CUnionEntity
+    def CUnion.entity_class
+      CUnionEntity
+    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.
+    #
+    # Example:
+    #
+    #   require 'dl/struct'
+    #   require 'dl/cparser'
+    #
+    #   include Fiddle::CParser
+    #
+    #   types, members = parse_struct_signature(['int i','char c'])
+    #
+    #   MyStruct = Fiddle::CStructBuilder.create(CUnion, types, members)
+    #
+    #   obj = MyStruct.allocate
+    #
+    def create(klass, types, members)
+      new_class = Class.new(klass){
+        define_method(:initialize){|addr|
+          @entity = klass.entity_class.new(addr, types)
+          @entity.assign_names(members)
+        }
+        define_method(:to_ptr){ @entity }
+        define_method(:to_i){ @entity.to_i }
+        members.each{|name|
+          define_method(name){ @entity[name] }
+          define_method(name + "="){|val| @entity[name] = val }
+        }
+      }
+      size = klass.entity_class.size(types)
+      new_class.module_eval(<<-EOS, __FILE__, __LINE__+1)
+        def new_class.size()
+          #{size}
+        end
+        def new_class.malloc()
+          addr = Fiddle.malloc(#{size})
+          new(addr)
+        end
+      EOS
+      return new_class
+    end
+    module_function :create
+  end
+
+  # A C struct wrapper
+  class CStructEntity < Fiddle::Pointer
+    include PackInfo
+    include ValueUtil
+
+    # Allocates a C struct the +types+ provided.  The C function +func+ is
+    # called when the instance is garbage collected.
+    def CStructEntity.malloc(types, func = nil)
+      addr = Fiddle.malloc(CStructEntity.size(types))
+      CStructEntity.new(addr, types, func)
+    end
+
+    # Given +types+, returns the offset for the packed sizes of those 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
+
+        align = PackInfo::ALIGN_MAP[type]
+        offset = PackInfo.align(last_offset, align) +
+                 (PackInfo::SIZE_MAP[type] * count)
+
+        align
+      }.max
+
+      PackInfo.align(offset, max_align)
+    end
+
+    # Wraps the C pointer +addr+ as a C struct with the given +types+.  The C
+    # function +func+ is called when the instance is garbage collected.
+    #
+    # See also Fiddle::CPtr.new
+    def initialize(addr, types, func = nil)
+      set_ctypes(types)
+      super(addr, @size, func)
+    end
+
+    # Set the names of the +members+ in this C struct
+    def assign_names(members)
+      @members = members
+    end
+
+    # Given +types+, calculate the offsets and sizes for the types in the
+    # struct.
+    def set_ctypes(types)
+      @ctypes = types
+      @offset = []
+      offset = 0
+
+      max_align = types.map { |type, count = 1|
+        orig_offset = offset
+        align = ALIGN_MAP[type]
+        offset = PackInfo.align(orig_offset, align)
+
+        @offset << offset
+
+        offset += (SIZE_MAP[type] * count)
+
+        align
+      }.max
+
+      @size = PackInfo.align(offset, max_align)
+    end
+
+    # Fetch struct member +name+
+    def [](name)
+      idx = @members.index(name)
+      if( idx.nil? )
+        raise(ArgumentError, "no such member: #{name}")
+      end
+      ty = @ctypes[idx]
+      if( ty.is_a?(Array) )
+        r = super(@offset[idx], SIZE_MAP[ty[0]] * ty[1])
+      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| CPtr.new(v)}
+        end
+      when TYPE_VOIDP
+        val = CPtr.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 val.collect{|v| unsigned_value(v,ty[0])}
+      else
+        return val
+      end
+    end
+
+    # Set struct member +name+, to value +val+
+    def []=(name, val)
+      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
+
+    def to_s() # :nodoc:
+      super(@size)
+    end
+  end
+
+  # A C union wrapper
+  class CUnionEntity < CStructEntity
+    include PackInfo
+
+    # Allocates a C union the +types+ provided.  The C function +func+ is
+    # called when the instance is garbage collected.
+    def CUnionEntity.malloc(types, func=nil)
+      addr = Fiddle.malloc(CUnionEntity.size(types))
+      CUnionEntity.new(addr, types, func)
+    end
+
+    # Given +types+, returns the size needed for the union.
+    #
+    #   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|
+        PackInfo::SIZE_MAP[type] * count
+      }.max
+    end
+
+    # Given +types+, calculate the necessary offset and for each union member
+    def set_ctypes(types)
+      @ctypes = types
+      @offset = Array.new(types.length, 0)
+      @size   = self.class.size types
+    end
+  end
+end
+