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/*
This file is part of solidity.
solidity is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
solidity is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with solidity. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @author Christian <c@ethdev.com>
* @date 2015
* Code generation utils that handle arrays.
*/
#pragma once
#include <memory>
namespace dev
{
namespace solidity
{
class CompilerContext;
class Type;
class ArrayType;
using TypePointer = std::shared_ptr<Type const>;
/**
* Class that provides code generation for handling arrays.
*/
class ArrayUtils
{
public:
explicit ArrayUtils(CompilerContext& _context): m_context(_context) {}
/// Copies an array to an array in storage. The arrays can be of different types only if
/// their storage representation is the same.
/// Stack pre: source_reference [source_length] target_reference
/// Stack post: target_reference
void copyArrayToStorage(ArrayType const& _targetType, ArrayType const& _sourceType) const;
/// Copies the data part of an array (which cannot be dynamically nested) from anywhere
/// to a given position in memory.
/// This always copies contained data as is (i.e. structs and fixed-size arrays are copied in
/// place as required by the ABI encoding). Use CompilerUtils::convertType if you want real
/// memory copies of nested arrays.
/// Stack pre: memory_offset source_item
/// Stack post: memory_offest + length(padded)
void copyArrayToMemory(ArrayType const& _sourceType, bool _padToWordBoundaries = true) const;
/// Clears the given dynamic or static array.
/// Stack pre: storage_ref storage_byte_offset
/// Stack post:
void clearArray(ArrayType const& _type) const;
/// Clears the length and data elements of the array referenced on the stack.
/// Stack pre: reference (excludes byte offset)
/// Stack post:
void clearDynamicArray(ArrayType const& _type) const;
/// Changes the size of a dynamic array and clears the tail if it is shortened.
/// Stack pre: reference (excludes byte offset) new_length
/// Stack post:
void resizeDynamicArray(ArrayType const& _type) const;
/// Increments the size of a dynamic array by one.
/// Does not touch the new data element. In case of a byte array, this might move the
/// data.
/// Stack pre: reference (excludes byte offset)
/// Stack post: new_length
void incrementDynamicArraySize(ArrayType const& _type) const;
/// Decrements the size of a dynamic array by one if length is nonzero. Returns otherwise.
/// Clears the removed data element. In case of a byte array, this might move the data.
/// Stack pre: reference
/// Stack post:
void popStorageArrayElement(ArrayType const& _type) const;
/// Appends a loop that clears a sequence of storage slots of the given type (excluding end).
/// Stack pre: end_ref start_ref
/// Stack post: end_ref
void clearStorageLoop(TypePointer const& _type) const;
/// Converts length to size (number of storage slots or calldata/memory bytes).
/// if @a _pad then add padding to multiples of 32 bytes for calldata/memory.
/// Stack pre: length
/// Stack post: size
void convertLengthToSize(ArrayType const& _arrayType, bool _pad = false) const;
/// Retrieves the length (number of elements) of the array ref on the stack. This also
/// works for statically-sized arrays.
/// @param _stackDepth number of stack elements between top of stack and top (!) of reference
/// Stack pre: reference (excludes byte offset for dynamic storage arrays)
/// Stack post: reference length
void retrieveLength(ArrayType const& _arrayType, unsigned _stackDepth = 0) const;
/// Stores the length of an array of type @a _arrayType in storage. The length itself is stored
/// on the stack at position @a _stackDepthLength and the storage reference at @a _stackDepthRef.
/// If @a _arrayType is a byte array, takes tight coding into account.
void storeLength(ArrayType const& _arrayType, unsigned _stackDepthLength = 0, unsigned _stackDepthRef = 1) const;
/// Performs bounds checking and returns a reference on the stack.
/// Stack pre: reference [length] index
/// Stack post (storage): storage_slot byte_offset
/// Stack post: memory/calldata_offset
void accessIndex(ArrayType const& _arrayType, bool _doBoundsCheck = true) const;
private:
/// Adds the given number of bytes to a storage byte offset counter and also increments
/// the storage offset if adding this number again would increase the counter over 32.
/// @param byteOffsetPosition the stack offset of the storage byte offset
/// @param storageOffsetPosition the stack offset of the storage slot offset
void incrementByteOffset(unsigned _byteSize, unsigned _byteOffsetPosition, unsigned _storageOffsetPosition) const;
CompilerContext& m_context;
};
}
}
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