Add bin and edit workflow

bin/gems/ffi-1.17.1-x86_64-linux-gnu/lib/ffi/struct_layout_builder.rb

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+#
+# Copyright (C) 2008-2010 Wayne Meissner
+#
+# This file is part of ruby-ffi.
+#
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are met:
+#
+# * Redistributions of source code must retain the above copyright notice, this
+#   list of conditions and the following disclaimer.
+# * Redistributions in binary form must reproduce the above copyright notice
+#   this list of conditions and the following disclaimer in the documentation
+#   and/or other materials provided with the distribution.
+# * Neither the name of the Ruby FFI project nor the names of its contributors
+#   may be used to endorse or promote products derived from this software
+#   without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+# DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
+# FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+# DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+# SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+
+module FFI
+
+  # Build a {StructLayout struct layout}.
+  class StructLayoutBuilder
+    attr_reader :size
+    attr_reader :alignment
+
+    def initialize
+      @size = 0
+      @alignment = 1
+      @min_alignment = 1
+      @packed = false
+      @union = false
+      @fields = Array.new
+    end
+
+    # Set size attribute with +size+ only if +size+ is greater than attribute value.
+    # @param [Integer] size
+    def size=(size)
+      @size = size if size > @size
+    end
+
+    # Set alignment attribute with +align+ only if it is greater than attribute value.
+    # @param [Integer] align
+    def alignment=(align)
+      @alignment = align if align > @alignment
+      @min_alignment = align
+    end
+
+    # Set union attribute.
+    # Set to +true+ to build a {Union} instead of a {Struct}.
+    # @param [Boolean] is_union
+    # @return [is_union]
+    def union=(is_union)
+      @union = is_union
+    end
+
+    # Building a {Union} or a {Struct} ?
+    #
+    # @return [Boolean]
+    #
+    def union?
+      @union
+    end
+
+    # Set packed attribute
+    # @overload packed=(packed) Set alignment and packed attributes to
+    #   +packed+.
+    #
+    #   @param [Integer] packed
+    #
+    #   @return [packed]
+    # @overload packed=(packed) Set packed attribute.
+    #   @param packed
+    #
+    #   @return [0,1]
+    #
+    def packed=(packed)
+      if packed.is_a?(0.class)
+        @alignment = packed
+        @packed = packed
+      else
+        @packed = packed ? 1 : 0
+      end
+    end
+
+
+    # List of number types
+    NUMBER_TYPES = [
+      Type::INT8,
+      Type::UINT8,
+      Type::INT16,
+      Type::UINT16,
+      Type::INT32,
+      Type::UINT32,
+      Type::LONG,
+      Type::ULONG,
+      Type::INT64,
+      Type::UINT64,
+      Type::FLOAT32,
+      Type::FLOAT64,
+      Type::LONGDOUBLE,
+      Type::BOOL,
+    ].freeze
+
+    # @param [String, Symbol] name name of the field
+    # @param [Array, DataConverter, Struct, StructLayout::Field, Symbol, Type] type type of the field
+    # @param [Integer, nil] offset
+    # @return [self]
+    # Add a field to the builder.
+    # @note Setting +offset+ to +nil+ or +-1+ is equivalent to +0+.
+    def add(name, type, offset = nil)
+
+      if offset.nil? || offset == -1
+        offset = @union ? 0 : align(@size, @packed ? [ @packed, type.alignment ].min : [ @min_alignment, type.alignment ].max)
+      end
+
+      #
+      # If a FFI::Type type was passed in as the field arg, try and convert to a StructLayout::Field instance
+      #
+      field = type.is_a?(StructLayout::Field) ? type : field_for_type(name, offset, type)
+      @fields << field
+      @alignment = [ @alignment, field.alignment ].max unless @packed
+      @size = [ @size, field.size + (@union ? 0 : field.offset) ].max
+
+      return self
+    end
+
+    # @param (see #add)
+    # @return (see #add)
+    # Same as {#add}.
+    # @see #add
+    def add_field(name, type, offset = nil)
+      add(name, type, offset)
+    end
+
+    # @param (see #add)
+    # @return (see #add)
+    # Add a struct as a field to the builder.
+    def add_struct(name, type, offset = nil)
+      add(name, Type::Struct.new(type), offset)
+    end
+
+    # @param name (see #add)
+    # @param type (see #add)
+    # @param [Integer] count array length
+    # @param offset (see #add)
+    # @return (see #add)
+    # Add an array as a field to the builder.
+    def add_array(name, type, count, offset = nil)
+      add(name, Type::Array.new(type, count), offset)
+    end
+
+    # @return [StructLayout]
+    # Build and return the struct layout.
+    def build
+      # Add tail padding if the struct is not packed
+      size = @packed ? @size : align(@size, @alignment)
+
+      layout = StructLayout.new(@fields, size, @alignment)
+      layout.__union! if @union
+      layout
+    end
+
+    private
+
+    # @param [Integer] offset
+    # @param [Integer] align
+    # @return [Integer]
+    def align(offset, align)
+      align + ((offset - 1) & ~(align - 1));
+    end
+
+    # @param (see #add)
+    # @return [StructLayout::Field]
+    def field_for_type(name, offset, type)
+      field_class = case
+      when type.is_a?(Type::Function)
+        StructLayout::Function
+
+      when type.is_a?(Type::Struct)
+        StructLayout::InnerStruct
+
+      when type.is_a?(Type::Array)
+        StructLayout::Array
+
+      when type.is_a?(FFI::Enum)
+        StructLayout::Enum
+
+      when NUMBER_TYPES.include?(type)
+        StructLayout::Number
+
+      when type == Type::POINTER
+        StructLayout::Pointer
+
+      when type == Type::STRING
+        StructLayout::String
+
+      when type.is_a?(Class) && type < StructLayout::Field
+        type
+
+      when type.is_a?(DataConverter)
+        return StructLayout::Mapped.new(name, offset, Type::Mapped.new(type), field_for_type(name, offset, type.native_type))
+
+      when type.is_a?(Type::Mapped)
+        return StructLayout::Mapped.new(name, offset, type, field_for_type(name, offset, type.native_type))
+
+      else
+        raise TypeError, "invalid struct field type #{type.inspect}"
+      end
+
+      field_class.new(name, offset, type)
+    end
+  end
+
+end