/*

  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/>.

*/

// SPDX-License-Identifier: GPL-3.0

/**

 * @author Christian <c@ethdev.com>

 * @date 2015

 * Code generation utils that handle arrays.

 */

#pragma once

#include <memory>

namespace solidity::frontend

{

class CompilerContext;

class Type;

class ArrayType;

/**

 * 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_offset + 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. Causes a Panic 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(Type 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;

  /// Checks whether the index is out of range and returns the absolute offset of the element reference[index]

  /// (i.e. reference + index * size_of_base_type).

  /// If @a _keepReference is true, the base reference to the beginning of the array is kept on the stack.

  /// Stack pre: reference [length] index

  /// Stack post (storage): [reference] storage_slot byte_offset

  /// Stack post: [reference] memory/calldata_offset

  void accessIndex(ArrayType const& _arrayType, bool _doBoundsCheck = true, bool _keepReference = false) const;

  /// Access calldata array's element and put it on stack.

  /// Stack pre: reference [length] index

  /// Stack post: value

  void accessCallDataArrayElement(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;

};

}