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			321 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			321 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
/*
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	This file is part of cpp-ethereum.
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	cpp-ethereum is free software: you can redistribute it and/or modify
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	it under the terms of the GNU General Public License as published by
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	the Free Software Foundation, either version 3 of the License, or
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	(at your option) any later version.
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	cpp-ethereum is distributed in the hope that it will be useful,
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	but WITHOUT ANY WARRANTY; without even the implied warranty of
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	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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	GNU General Public License for more details.
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	You should have received a copy of the GNU General Public License
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	along with cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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 * @author Christian <c@ethdev.com>
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 * @date 2015
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 * Code generation utils that handle arrays.
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 */
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#include <libsolidity/ArrayUtils.h>
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#include <libevmcore/Instruction.h>
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#include <libsolidity/CompilerContext.h>
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#include <libsolidity/CompilerUtils.h>
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#include <libsolidity/Types.h>
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#include <libsolidity/Utils.h>
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#include <libsolidity/LValue.h>
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using namespace std;
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using namespace dev;
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using namespace solidity;
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void ArrayUtils::copyArrayToStorage(ArrayType const& _targetType, ArrayType const& _sourceType) const
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{
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	// stack layout: [source_ref] target_ref (top)
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	// need to leave target_ref on the stack at the end
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	solAssert(_targetType.getLocation() == ArrayType::Location::Storage, "");
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	solAssert(
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		_sourceType.getLocation() == ArrayType::Location::CallData ||
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			_sourceType.getLocation() == ArrayType::Location::Storage,
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		"Given array location not implemented."
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	);
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	IntegerType uint256(256);
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	Type const* targetBaseType = _targetType.isByteArray() ? &uint256 : &(*_targetType.getBaseType());
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	Type const* sourceBaseType = _sourceType.isByteArray() ? &uint256 : &(*_sourceType.getBaseType());
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	// this copies source to target and also clears target if it was larger
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	// TODO unroll loop for small sizes
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	// stack: source_ref [source_length] target_ref
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	// store target_ref
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	for (unsigned i = _sourceType.getSizeOnStack(); i > 0; --i)
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		m_context << eth::swapInstruction(i);
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	if (_sourceType.getLocation() != ArrayType::Location::CallData || !_sourceType.isDynamicallySized())
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		retrieveLength(_sourceType); // otherwise, length is already there
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	// stack: target_ref source_ref source_length
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	m_context << eth::Instruction::DUP3;
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	// stack: target_ref source_ref source_length target_ref
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	retrieveLength(_targetType);
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	// stack: target_ref source_ref source_length target_ref target_length
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	if (_targetType.isDynamicallySized())
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		// store new target length
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		m_context << eth::Instruction::DUP3 << eth::Instruction::DUP3 << eth::Instruction::SSTORE;
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	if (sourceBaseType->getCategory() == Type::Category::Mapping)
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	{
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		solAssert(targetBaseType->getCategory() == Type::Category::Mapping, "");
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		solAssert(_sourceType.getLocation() == ArrayType::Location::Storage, "");
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		// nothing to copy
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		m_context
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			<< eth::Instruction::POP << eth::Instruction::POP
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			<< eth::Instruction::POP << eth::Instruction::POP;
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		return;
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	}
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	// compute hashes (data positions)
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	m_context << eth::Instruction::SWAP1;
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	if (_targetType.isDynamicallySized())
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		CompilerUtils(m_context).computeHashStatic();
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	// stack: target_ref source_ref source_length target_length target_data_pos
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	m_context << eth::Instruction::SWAP1;
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	convertLengthToSize(_targetType);
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	m_context << eth::Instruction::DUP2 << eth::Instruction::ADD;
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	// stack: target_ref source_ref source_length target_data_pos target_data_end
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	m_context << eth::Instruction::SWAP3;
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	// stack: target_ref target_data_end source_length target_data_pos source_ref
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	// skip copying if source length is zero
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	m_context << eth::Instruction::DUP3 << eth::Instruction::ISZERO;
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	eth::AssemblyItem copyLoopEnd = m_context.newTag();
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	m_context.appendConditionalJumpTo(copyLoopEnd);
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	if (_sourceType.getLocation() == ArrayType::Location::Storage && _sourceType.isDynamicallySized())
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		CompilerUtils(m_context).computeHashStatic();
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	// stack: target_ref target_data_end source_length target_data_pos source_data_pos
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	m_context << eth::Instruction::SWAP2;
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	convertLengthToSize(_sourceType);
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	m_context << eth::Instruction::DUP3 << eth::Instruction::ADD;
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	// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end
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	eth::AssemblyItem copyLoopStart = m_context.newTag();
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	m_context << copyLoopStart;
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	// check for loop condition
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	m_context
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		<< eth::Instruction::DUP3 << eth::Instruction::DUP2
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		<< eth::Instruction::GT << eth::Instruction::ISZERO;
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	m_context.appendConditionalJumpTo(copyLoopEnd);
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	// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end
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	// copy
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	if (sourceBaseType->getCategory() == Type::Category::Array)
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	{
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		m_context << eth::Instruction::DUP3 << eth::Instruction::DUP3;
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		copyArrayToStorage(
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			dynamic_cast<ArrayType const&>(*targetBaseType),
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			dynamic_cast<ArrayType const&>(*sourceBaseType)
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		);
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		m_context << eth::Instruction::POP;
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	}
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	else
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	{
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		m_context << eth::Instruction::DUP3;
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		if (_sourceType.getLocation() == ArrayType::Location::Storage)
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			StorageItem(m_context, *sourceBaseType).retrieveValue(SourceLocation(), true);
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		else if (sourceBaseType->isValueType())
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			CompilerUtils(m_context).loadFromMemoryDynamic(*sourceBaseType, true, true, false);
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		else
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			solAssert(false, "Copying of unknown type requested: " + sourceBaseType->toString());
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		m_context << eth::dupInstruction(2 + sourceBaseType->getSizeOnStack());
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		StorageItem(m_context, *targetBaseType).storeValue(*sourceBaseType, SourceLocation(), true);
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	}
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	// increment source
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	m_context
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		<< eth::Instruction::SWAP2
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		<< (_sourceType.getLocation() == ArrayType::Location::Storage ?
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			sourceBaseType->getStorageSize() :
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			sourceBaseType->getCalldataEncodedSize())
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		<< eth::Instruction::ADD
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		<< eth::Instruction::SWAP2;
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	// increment target
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	m_context
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		<< eth::Instruction::SWAP1
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		<< targetBaseType->getStorageSize()
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		<< eth::Instruction::ADD
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		<< eth::Instruction::SWAP1;
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	m_context.appendJumpTo(copyLoopStart);
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	m_context << copyLoopEnd;
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	// zero-out leftovers in target
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	// stack: target_ref target_data_end source_data_pos target_data_pos source_data_end
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	m_context << eth::Instruction::POP << eth::Instruction::SWAP1 << eth::Instruction::POP;
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	// stack: target_ref target_data_end target_data_pos_updated
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	clearStorageLoop(*targetBaseType);
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	m_context << eth::Instruction::POP;
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}
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void ArrayUtils::clearArray(ArrayType const& _type) const
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{
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	solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
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	if (_type.isDynamicallySized())
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		clearDynamicArray(_type);
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	else if (_type.getLength() == 0 || _type.getBaseType()->getCategory() == Type::Category::Mapping)
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		m_context << eth::Instruction::POP;
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	else if (_type.getLength() < 5) // unroll loop for small arrays @todo choose a good value
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	{
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		solAssert(!_type.isByteArray(), "");
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		for (unsigned i = 1; i < _type.getLength(); ++i)
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		{
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			StorageItem(m_context, *_type.getBaseType()).setToZero(SourceLocation(), false);
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			m_context << u256(_type.getBaseType()->getStorageSize()) << eth::Instruction::ADD;
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		}
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		StorageItem(m_context, *_type.getBaseType()).setToZero(SourceLocation(), true);
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	}
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	else
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	{
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		solAssert(!_type.isByteArray(), "");
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		m_context
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			<< eth::Instruction::DUP1 << u256(_type.getLength())
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			<< u256(_type.getBaseType()->getStorageSize())
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			<< eth::Instruction::MUL << eth::Instruction::ADD << eth::Instruction::SWAP1;
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		clearStorageLoop(*_type.getBaseType());
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		m_context << eth::Instruction::POP;
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	}
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}
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void ArrayUtils::clearDynamicArray(ArrayType const& _type) const
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{
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	solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
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	solAssert(_type.isDynamicallySized(), "");
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	// fetch length
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	m_context << eth::Instruction::DUP1 << eth::Instruction::SLOAD;
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	// set length to zero
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	m_context << u256(0) << eth::Instruction::DUP3 << eth::Instruction::SSTORE;
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	// stack: ref old_length
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	convertLengthToSize(_type);
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	// compute data positions
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	m_context << eth::Instruction::SWAP1;
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	CompilerUtils(m_context).computeHashStatic();
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	// stack: len data_pos (len is in slots for byte array and in items for other arrays)
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	m_context << eth::Instruction::SWAP1 << eth::Instruction::DUP2 << eth::Instruction::ADD
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		<< eth::Instruction::SWAP1;
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	// stack: data_pos_end data_pos
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	if (_type.isByteArray())
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		clearStorageLoop(IntegerType(256));
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	else
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		clearStorageLoop(*_type.getBaseType());
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	// cleanup
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	m_context << eth::Instruction::POP;
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}
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void ArrayUtils::resizeDynamicArray(const ArrayType& _type) const
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{
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	solAssert(_type.getLocation() == ArrayType::Location::Storage, "");
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	solAssert(_type.isDynamicallySized(), "");
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	eth::AssemblyItem resizeEnd = m_context.newTag();
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	// stack: ref new_length
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	// fetch old length
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	m_context << eth::Instruction::DUP2 << eth::Instruction::SLOAD;
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	// stack: ref new_length old_length
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	// store new length
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	m_context << eth::Instruction::DUP2 << eth::Instruction::DUP4 << eth::Instruction::SSTORE;
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	// skip if size is not reduced
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	m_context << eth::Instruction::DUP2 << eth::Instruction::DUP2
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		<< eth::Instruction::ISZERO << eth::Instruction::GT;
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	m_context.appendConditionalJumpTo(resizeEnd);
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	// size reduced, clear the end of the array
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	// stack: ref new_length old_length
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	convertLengthToSize(_type);
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	m_context << eth::Instruction::DUP2;
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	convertLengthToSize(_type);
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	// stack: ref new_length old_size new_size
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	// compute data positions
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	m_context << eth::Instruction::DUP4;
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	CompilerUtils(m_context).computeHashStatic();
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	// stack: ref new_length old_size new_size data_pos
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	m_context << eth::Instruction::SWAP2 << eth::Instruction::DUP3 << eth::Instruction::ADD;
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	// stack: ref new_length data_pos new_size delete_end
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	m_context << eth::Instruction::SWAP2 << eth::Instruction::ADD;
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	// stack: ref new_length delete_end delete_start
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	if (_type.isByteArray())
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		clearStorageLoop(IntegerType(256));
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	else
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		clearStorageLoop(*_type.getBaseType());
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	m_context << resizeEnd;
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	// cleanup
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	m_context << eth::Instruction::POP << eth::Instruction::POP << eth::Instruction::POP;
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}
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void ArrayUtils::clearStorageLoop(Type const& _type) const
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{
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	if (_type.getCategory() == Type::Category::Mapping)
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	{
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		m_context << eth::Instruction::POP;
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		return;
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	}
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	// stack: end_pos pos
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	eth::AssemblyItem loopStart = m_context.newTag();
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	m_context << loopStart;
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	// check for loop condition
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	m_context << eth::Instruction::DUP1 << eth::Instruction::DUP3
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			   << eth::Instruction::GT << eth::Instruction::ISZERO;
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	eth::AssemblyItem zeroLoopEnd = m_context.newTag();
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	m_context.appendConditionalJumpTo(zeroLoopEnd);
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	// delete
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	StorageItem(m_context, _type).setToZero(SourceLocation(), false);
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	// increment
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	m_context << u256(1) << eth::Instruction::ADD;
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	m_context.appendJumpTo(loopStart);
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	// cleanup
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	m_context << zeroLoopEnd;
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	m_context << eth::Instruction::POP;
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}
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void ArrayUtils::convertLengthToSize(ArrayType const& _arrayType, bool _pad) const
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{
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	if (_arrayType.getLocation() == ArrayType::Location::Storage)
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	{
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		if (_arrayType.isByteArray())
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			m_context << u256(31) << eth::Instruction::ADD
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				<< u256(32) << eth::Instruction::SWAP1 << eth::Instruction::DIV;
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		else if (_arrayType.getBaseType()->getStorageSize() > 1)
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			m_context << _arrayType.getBaseType()->getStorageSize() << eth::Instruction::MUL;
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	}
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	else
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	{
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		if (!_arrayType.isByteArray())
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			m_context << _arrayType.getBaseType()->getCalldataEncodedSize() << eth::Instruction::MUL;
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		else if (_pad)
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			m_context << u256(31) << eth::Instruction::ADD
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				<< u256(32) << eth::Instruction::DUP1
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				<< eth::Instruction::SWAP2 << eth::Instruction::DIV << eth::Instruction::MUL;
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	}
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}
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void ArrayUtils::retrieveLength(ArrayType const& _arrayType) const
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{
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	if (!_arrayType.isDynamicallySized())
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		m_context << _arrayType.getLength();
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	else
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	{
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		m_context << eth::Instruction::DUP1;
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		switch (_arrayType.getLocation())
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		{
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		case ArrayType::Location::CallData:
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			// length is stored on the stack
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			break;
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		case ArrayType::Location::Memory:
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			m_context << eth::Instruction::MLOAD;
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			break;
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		case ArrayType::Location::Storage:
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			m_context << eth::Instruction::SLOAD;
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			break;
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		}
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	}
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}
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