From e5ae5955b97009233fc46ac04070073750240698 Mon Sep 17 00:00:00 2001
From: chriseth <c@ethdev.com>
Date: Wed, 24 Jun 2015 17:25:36 +0200
Subject: Initialisation of memory types.

---
 ExpressionCompiler.cpp | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

(limited to 'ExpressionCompiler.cpp')

diff --git a/ExpressionCompiler.cpp b/ExpressionCompiler.cpp
index 7d6ed346..fb10eb83 100644
--- a/ExpressionCompiler.cpp
+++ b/ExpressionCompiler.cpp
@@ -56,6 +56,62 @@ void ExpressionCompiler::appendStateVariableInitialization(VariableDeclaration c
 	StorageItem(m_context, _varDecl).storeValue(*_varDecl.getType(), _varDecl.getLocation(), true);
 }
 
+void ExpressionCompiler::appendStackVariableInitialisation(Type const& _type, bool _toMemory)
+{
+	CompilerUtils utils(m_context);
+	auto const* referenceType = dynamic_cast<ReferenceType const*>(&_type);
+	if (!referenceType || referenceType->location() == DataLocation::Storage)
+	{
+		for (size_t i = 0; i < _type.getSizeOnStack(); ++i)
+			m_context << u256(0);
+		if (_toMemory)
+			utils.storeInMemoryDynamic(_type);
+		return;
+	}
+	solAssert(referenceType->location() == DataLocation::Memory, "");
+	if (!_toMemory)
+	{
+		// allocate memory
+		utils.fetchFreeMemoryPointer();
+		m_context << eth::Instruction::DUP1 << u256(max(32u, _type.getCalldataEncodedSize()));
+		m_context << eth::Instruction::ADD;
+		utils.storeFreeMemoryPointer();
+		m_context << eth::Instruction::DUP1;
+	}
+
+	if (auto structType = dynamic_cast<StructType const*>(&_type))
+		for (auto const& member: structType->getMembers())
+			appendStackVariableInitialisation(*member.type, true);
+	else if (auto arrayType = dynamic_cast<ArrayType const*>(&_type))
+	{
+		if (arrayType->isDynamicallySized())
+		{
+			// zero length
+			m_context << u256(0);
+			CompilerUtils(m_context).storeInMemoryDynamic(IntegerType(256));
+		}
+		else if (arrayType->getLength() > 0)
+		{
+			m_context << arrayType->getLength() << eth::Instruction::SWAP1;
+			// stack: items_to_do memory_pos
+			auto repeat = m_context.newTag();
+			m_context << repeat;
+			appendStackVariableInitialisation(*arrayType->getBaseType(), true);
+			m_context << eth::Instruction::SWAP1 << u256(1) << eth::Instruction::SWAP1;
+			m_context << eth::Instruction::SUB << eth::Instruction::SWAP1;
+			m_context << eth::Instruction::DUP2;
+			m_context.appendConditionalJumpTo(repeat);
+			m_context << eth::Instruction::SWAP1 << eth::Instruction::POP;
+		}
+	}
+	else
+		solAssert(false, "Requested initialisation for unknown type: " + _type.toString());
+
+	if (!_toMemory)
+		// remove the updated memory pointer
+		m_context << eth::Instruction::POP;
+}
+
 void ExpressionCompiler::appendStateVariableAccessor(VariableDeclaration const& _varDecl)
 {
 	CompilerContext::LocationSetter locationSetter(m_context, _varDecl);
-- 
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