10000 [ruby/fiddle] Fix assignment to array within struct (#26) · nobu/ruby@b036440 · GitHub
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sinisterchipmunknobu
sinisterchipmunk
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[ruby/fiddle] Fix assignment to array within struct (ruby#26)
* Allow access to a struct's underlying memory with `struct[offset, length]`. ruby/fiddle@24083690a6
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‎ext/fiddle/lib/fiddle/struct.rb

Lines changed: 28 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -20,6 +20,33 @@ def CUnion.entity_class
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end
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end
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# Wrapper for arrays within a struct
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class StructArray < Array
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include ValueUtil
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def initialize(ptr, type, initial_values)
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@ptr = ptr
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@type = type
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@align = PackInfo::ALIGN_MAP[type]
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@size = Fiddle::PackInfo::SIZE_MAP[type]
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@pack_format = Fiddle::PackInfo::PACK_MAP[type]
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super(initial_values.collect { |v| unsigned_value(v, type) })
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end
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def to_ptr
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@ptr
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end
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def []=(index, value)
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if index < 0 || index >= size
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raise IndexError, 'index %d outside of array bounds 0...%d' % [index, size]
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end
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to_ptr[index * @size, @size] = [value].pack(@pack_format)
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super(index, value)
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end
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end
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# Used to construct C classes (CUnion, CStruct, etc)
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#
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# Fiddle::Importer#struct and Fiddle::Importer#union wrap this functionality in an
@@ -191,7 +218,7 @@ def [](*args)
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if( ty.is_a?(Integer) && (ty < 0) )
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return unsigned_value(val, ty)
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elsif( ty.is_a?(Array) && (ty[0] < 0) )
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return val.collect{|v| unsigned_value(v,ty[0])}
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return StructArray.new(self + @offset[idx], ty[0], val)
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else
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return val
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end

‎test/fiddle/test_import.rb

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -129,6 +129,20 @@ def test_value()
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assert_equal([0,1,2], ary.value)
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end
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def test_struct_array_assignment()
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instance = Fiddle::Importer.struct(["unsigned int stages[3]"]).malloc
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instance.stages[0] = 1024
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instance.stages[1] = 10
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instance.stages[2] = 100
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assert_equal 1024, instance.stages[0]
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assert_equal 10, instance.stages[1]
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assert_equal 100, instance.stages[2]
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assert_equal [1024, 10, 100].pack(Fiddle::PackInfo::PACK_MAP[-Fiddle::TYPE_INT] * 3),
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instance.to_ptr[0, 3 * Fiddle::SIZEOF_INT]
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assert_raise(IndexError) { instance.stages[-1] = 5 }
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assert_raise(IndexError) { instance.stages[3] = 5 }
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end
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def test_struct()
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s = LIBC::MyStruct.malloc()
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s.num = [0,1,2,3,4]

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