Method accessIndex

libsolidity/codegen/ArrayUtils.cpp:690–787

}

void ArrayUtils::accessIndex(ArrayType const& _arrayType, bool _doBoundsCheck, bool _keepReference) const
{
	/// Stack: reference [length] index
	DataLocation location = _arrayType.location();

	if (_doBoundsCheck)
	{
		// retrieve length
		ArrayUtils::retrieveLength(_arrayType, 1);
		// Stack: ref [length] index length
		// check out-of-bounds access
		m_context << Instruction::DUP2 << Instruction::LT << Instruction::ISZERO;
		// out-of-bounds access throws exception
		m_context.appendConditionalPanic(util::PanicCode::ArrayOutOfBounds);
	}
	if (location == DataLocation::CallData && _arrayType.isDynamicallySized())
		// remove length if present
		m_context << Instruction::SWAP1 << Instruction::POP;

	// stack: <base_ref> <index>
	switch (location)
	{
	case DataLocation::Memory:
		// stack: <base_ref> <index>
		if (!_arrayType.isByteArrayOrString())
			m_context << u256(_arrayType.memoryHeadSize()) << Instruction::MUL;
		if (_arrayType.isDynamicallySized())
			m_context << u256(32) << Instruction::ADD;
		if (_keepReference)
			m_context << Instruction::DUP2;
		m_context << Instruction::ADD;
		break;
	case DataLocation::CallData:
		if (!_arrayType.isByteArrayOrString())
		{
			m_context << _arrayType.calldataStride();
			m_context << Instruction::MUL;
		}
		// stack: <base_ref> <index * size>
		if (_keepReference)
			m_context << Instruction::DUP2;
		m_context << Instruction::ADD;
		break;
	case DataLocation::Storage:
	{
		if (_keepReference)
			m_context << Instruction::DUP2;
		else
			m_context << Instruction::SWAP1;
		// stack: [<base_ref>] <index> <base_ref>

		evmasm::AssemblyItem endTag = m_context.newTag();
		if (_arrayType.isByteArrayOrString())
		{
			// Special case of short byte arrays.
			m_context << Instruction::SWAP1;
			m_context << Instruction::DUP2 << Instruction::SLOAD;
			m_context << u256(1) << Instruction::AND << Instruction::ISZERO;