runtime.rs

		value_len: u32,
	) -> Result<u32, TrapReason> {
		ctx.set_storage(KeyType::Fix, key_ptr, value_ptr, value_len)
	}

	/// Set the value at the given key in the contract storage.
	///
	/// The key and value lengths must not exceed the maximums defined by the contracts module
	/// parameters. Specifying a `value_len` of zero will store an empty value.
	///
	/// # Parameters
	///
	/// - `key_ptr`: pointer into the linear memory where the location to store the value is placed.
	/// - `key_len`: the length of the key in bytes.
	/// - `value_ptr`: pointer into the linear memory where the value to set is placed.
	/// - `value_len`: the length of the value in bytes.
	///
	/// # Return Value
	///
	/// Returns the size of the pre-existing value at the specified key if any. Otherwise
	/// `SENTINEL` is returned as a sentinel value.
	#[unstable]
	fn seal_set_storage(
		ctx: Runtime<E: Ext>,
		key_ptr: u32,
		key_len: u32,
		value_ptr: u32,
		value_len: u32,
	) -> Result<u32, TrapReason> {
		ctx.set_storage(KeyType::Variable(key_len), key_ptr, value_ptr, value_len)
	}

	/// Clear the value at the given key in the contract storage.
	///
	/// Equivalent to the newer version of `seal_clear_storage` with the exception of the return
	/// type. Still a valid thing to call when not interested in the return value.
	fn seal_clear_storage(ctx: Runtime<E: Ext>, key_ptr: u32) -> Result<(), TrapReason> {
		ctx.clear_storage(KeyType::Fix, key_ptr).map(|_| ())
	}

	/// Clear the value at the given key in the contract storage.
	///
	/// # Parameters
	///
	/// - `key_ptr`: pointer into the linear memory where the key is placed.
	/// - `key_len`: the length of the key in bytes.
	///
	/// # Return Value
	///
	/// Returns the size of the pre-existing value at the specified key if any. Otherwise
	/// `SENTINEL` is returned as a sentinel value.
	#[unstable]
	fn seal_clear_storage(
		ctx: Runtime<E: Ext>,
		key_ptr: u32,
		key_len: u32,
	) -> Result<u32, TrapReason> {
		ctx.clear_storage(KeyType::Variable(key_len), key_ptr)
	}

	/// Retrieve the value under the given key from storage.
	///
	/// This version is to be used with a fixed sized storage key. For runtimes supporting
	/// transparent hashing, please use the newer version of this function.
	///
	/// # Parameters
	///
	/// - `key_ptr`: pointer into the linear memory where the key of the requested value is placed.
	/// - `out_ptr`: pointer to the linear memory where the value is written to.
	/// - `out_len_ptr`: in-out pointer into linear memory where the buffer length is read from and
	///   the value length is written to.
	///
	/// # Errors
	///
	/// `ReturnCode::KeyNotFound`
	fn seal_get_storage(
		ctx: Runtime<E: Ext>,
		key_ptr: u32,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<ReturnCode, TrapReason> {
		ctx.get_storage(KeyType::Fix, key_ptr, out_ptr, out_len_ptr)
	}

	/// Retrieve the value under the given key from storage.
	///
	/// This version is to be used with a fixed sized storage key. For runtimes supporting
	/// transparent hashing, please use the newer version of this function.
	///
	/// The key length must not exceed the maximum defined by the contracts module parameter.
	///
	/// # Parameters
	///
	/// - `key_ptr`: pointer into the linear memory where the key of the requested value is placed.
	/// - `key_len`: the length of the key in bytes.
	/// - `out_ptr`: pointer to the linear memory where the value is written to.
	/// - `out_len_ptr`: in-out pointer into linear memory where the buffer length is read from and
	///   the value length is written to.
	///
	/// # Errors
	///
	/// `ReturnCode::KeyNotFound`
	#[unstable]
	fn seal_get_storage(
		ctx: Runtime<E: Ext>,
		key_ptr: u32,
		key_len: u32,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<ReturnCode, TrapReason> {
		ctx.get_storage(KeyType::Variable(key_len), key_ptr, out_ptr, out_len_ptr)
	}

	/// Checks whether there is a value stored under the given key.
	///
	/// This version is to be used with a fixed sized storage key. For runtimes supporting
	/// transparent hashing, please use the newer version of this function.
	///
	/// # Parameters
	///
	/// - `key_ptr`: pointer into the linear memory where the key of the requested value is placed.
	///
	/// # Return Value
	///
	/// Returns the size of the pre-existing value at the specified key if any. Otherwise
	/// `SENTINEL` is returned as a sentinel value.
	fn seal_contains_storage(ctx: Runtime<E: Ext>, key_ptr: u32) -> Result<u32, TrapReason> {
		ctx.contains_storage(KeyType::Fix, key_ptr)
	}

	/// Checks whether there is a value stored under the given key.
	///
	/// The key length must not exceed the maximum defined by the contracts module parameter.
	///
	/// # Parameters
	///
	/// - `key_ptr`: pointer into the linear memory where the key of the requested value is placed.
	/// - `key_len`: the length of the key in bytes.
	///
	/// # Return Value
	///
	/// Returns the size of the pre-existing value at the specified key if any. Otherwise
	/// `SENTINEL` is returned as a sentinel value.
	#[unstable]
	fn seal_contains_storage(
		ctx: Runtime<E: Ext>,
		key_ptr: u32,
		key_len: u32,
	) -> Result<u32, TrapReason> {
		ctx.contains_storage(KeyType::Variable(key_len), key_ptr)
	}

	/// Retrieve and remove the value under the given key from storage.
	///
	/// # Parameters
	///
	/// - `key_ptr`: pointer into the linear memory where the key of the requested value is placed.
	/// - `key_len`: the length of the key in bytes.
	/// - `out_ptr`: pointer to the linear memory where the value is written to.
	/// - `out_len_ptr`: in-out pointer into linear memory where the buffer length is read from and
	///   the value length is written to.
	///
	/// # Errors
	///
	/// `ReturnCode::KeyNotFound`
	#[unstable]
	fn seal_take_storage(
		ctx: Runtime<E: Ext>,
		key_ptr: u32,
		key_len: u32,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<ReturnCode, TrapReason> {
		let charged = ctx.charge_gas(RuntimeCosts::TakeStorage(ctx.ext.max_value_size()))?;
		let key = ctx.read_sandbox_memory(key_ptr, key_len)?;
		if let crate::storage::WriteOutcome::Taken(value) = ctx.ext.set_storage_transparent(
			&VarSizedKey::<E::T>::try_from(key).map_err(|_| Error::<E::T>::DecodingFailed)?,
			None,
			true,
		)? {
			ctx.adjust_gas(charged, RuntimeCosts::TakeStorage(value.len() as u32));
			ctx.write_sandbox_output(out_ptr, out_len_ptr, &value, false, already_charged)?;
			Ok(ReturnCode::Success)
		} else {
			ctx.adjust_gas(charged, RuntimeCosts::TakeStorage(0));
			Ok(ReturnCode::KeyNotFound)
		}
	}
	/// Transfer some value to another account.
	///
	/// # Parameters
	///
	/// - account_ptr: a pointer to the address of the beneficiary account Should be decodable as an
	///   `T::AccountId`. Traps otherwise.
	/// - account_len: length of the address buffer.
	/// - value_ptr: a pointer to the buffer with value, how much value to send. Should be decodable
	///   as a `T::Balance`. Traps otherwise.
	/// - value_len: length of the value buffer.
	///
	/// # Errors
	///
	/// `ReturnCode::TransferFailed`
	fn seal_transfer(
		ctx: Runtime<E: Ext>,
		account_ptr: u32,
		_account_len: u32,
		value_ptr: u32,
		_value_len: u32,
	) -> Result<ReturnCode, TrapReason> {
		ctx.charge_gas(RuntimeCosts::Transfer)?;
		let callee: <<E as Ext>::T as frame_system::Config>::AccountId =
			ctx.read_sandbox_memory_as(account_ptr)?;
		let value: BalanceOf<<E as Ext>::T> = ctx.read_sandbox_memory_as(value_ptr)?;
		let result = ctx.ext.transfer(&callee, value);
		match result {
			Ok(()) => Ok(ReturnCode::Success),
			Err(err) => {
				let code = Runtime::<E>::err_into_return_code(err)?;
				Ok(code)
			},
		}
	}

	/// Make a call to another contract.
	///
	/// # Deprecation
	///
	/// This is equivalent to calling the newer version of this function with
	/// `flags` set to `ALLOW_REENTRY`. See the newer version for documentation.
	///
	/// # Note
	///
	/// The values `_callee_len` and `_value_len` are ignored because the encoded sizes
	/// of those types are fixed through `[`MaxEncodedLen`]. The fields exist for backwards
	/// compatibility. Consider switching to the newest version of this function.
	fn seal_call(
		ctx: Runtime<E: Ext>,
		callee_ptr: u32,
		_callee_len: u32,
		gas: u64,
		value_ptr: u32,
		_value_len: u32,
		input_data_ptr: u32,
		input_data_len: u32,
		output_ptr: u32,
		output_len_ptr: u32,
	) -> Result<ReturnCode, TrapReason> {
		ctx.call(
			CallFlags::ALLOW_REENTRY,
			CallType::Call { callee_ptr, value_ptr, gas },
			input_data_ptr,
			input_data_len,
			output_ptr,
			output_len_ptr,
		)
	}

	/// Make a call to another contract.
	///
	/// The callees output buffer is copied to `output_ptr` and its length to `output_len_ptr`.
	/// The copy of the output buffer can be skipped by supplying the sentinel value
	/// of `SENTINEL` to `output_ptr`.
	///
	/// # Parameters
	///
	/// - flags: See [`CallFlags`] for a documenation of the supported flags.
	/// - callee_ptr: a pointer to the address of the callee contract. Should be decodable as an
	///   `T::AccountId`. Traps otherwise.
	/// - gas: how much gas to devote to the execution.
	/// - value_ptr: a pointer to the buffer with value, how much value to send. Should be decodable
	///   as a `T::Balance`. Traps otherwise.
	/// - input_data_ptr: a pointer to a buffer to be used as input data to the callee.
	/// - input_data_len: length of the input data buffer.
	/// - output_ptr: a pointer where the output buffer is copied to.
	/// - output_len_ptr: in-out pointer to where the length of the buffer is read from and the
	///   actual length is written to.
	///
	/// # Errors
	///
	/// An error means that the call wasn't successful output buffer is returned unless
	/// stated otherwise.
	///
	/// `ReturnCode::CalleeReverted`: Output buffer is returned.
	/// `ReturnCode::CalleeTrapped`
	/// `ReturnCode::TransferFailed`
	/// `ReturnCode::NotCallable`
	#[version(1)]
	fn seal_call(
		ctx: Runtime<E: Ext>,
		flags: u32,
		callee_ptr: u32,
		gas: u64,
		value_ptr: u32,
		input_data_ptr: u32,
		input_data_len: u32,
		output_ptr: u32,
		output_len_ptr: u32,
	) -> Result<ReturnCode, TrapReason> {
		ctx.call(
			CallFlags::from_bits(flags).ok_or(Error::<E::T>::InvalidCallFlags)?,
			CallType::Call { callee_ptr, value_ptr, gas },
			input_data_ptr,
			input_data_len,
			output_ptr,
			output_len_ptr,
		)
	}

	/// Execute code in the context (storage, caller, value) of the current contract.
	///
	/// Reentrancy protection is always disabled since the callee is allowed
	/// to modify the callers storage. This makes going through a reentrancy attack
	/// unnecessary for the callee when it wants to exploit the caller.
	///
	/// # Parameters
	///
	/// - flags: See [`CallFlags`] for a documentation of the supported flags.
	/// - code_hash: a pointer to the hash of the code to be called.
	/// - input_data_ptr: a pointer to a buffer to be used as input data to the callee.
	/// - input_data_len: length of the input data buffer.
	/// - output_ptr: a pointer where the output buffer is copied to.
	/// - output_len_ptr: in-out pointer to where the length of the buffer is read from and the
	///   actual length is written to.
	///
	/// # Errors
	///
	/// An error means that the call wasn't successful and no output buffer is returned unless
	/// stated otherwise.
	///
	/// `ReturnCode::CalleeReverted`: Output buffer is returned.
	/// `ReturnCode::CalleeTrapped`
	/// `ReturnCode::CodeNotFound`
	fn seal_delegate_call(
		ctx: Runtime<E: Ext>,
		flags: u32,
		code_hash_ptr: u32,
		input_data_ptr: u32,
		input_data_len: u32,
		output_ptr: u32,
		output_len_ptr: u32,
	) -> Result<ReturnCode, TrapReason> {
		ctx.call(
			CallFlags::from_bits(flags).ok_or(Error::<E::T>::InvalidCallFlags)?,
			CallType::DelegateCall { code_hash_ptr },
			input_data_ptr,
			input_data_len,
			output_ptr,
			output_len_ptr,
		)
	}
	/// Instantiate a contract with the specified code hash.
	///
	/// # Deprecation
	///
	/// This is equivalent to calling the newer version of this function. The newer version
	/// drops the now unnecessary length fields.
	///
	/// # Note
	///
	/// The values `_code_hash_len` and `_value_len` are ignored because the encoded sizes
	/// of those types are fixed through `[`MaxEncodedLen`]. The fields exist for backwards
	/// compatibility. Consider switching to the newest version of this function.
	fn seal_instantiate(
		ctx: Runtime<E: Ext>,
		code_hash_ptr: u32,
		_code_hash_len: u32,
		gas: u64,
		value_ptr: u32,
		_value_len: u32,
		input_data_ptr: u32,
		input_data_len: u32,
		address_ptr: u32,
		address_len_ptr: u32,
		output_ptr: u32,
		output_len_ptr: u32,
		salt_ptr: u32,
		salt_len: u32,
	) -> Result<ReturnCode, TrapReason> {
		ctx.instantiate(
			code_hash_ptr,
			gas,
			value_ptr,
			input_data_ptr,
			input_data_len,
			address_ptr,
			address_len_ptr,
			output_ptr,
			output_len_ptr,
			salt_ptr,
			salt_len,
		)
	}

	/// Instantiate a contract with the specified code hash.
	///
	/// This function creates an account and executes the constructor defined in the code specified
	/// by the code hash. The address of this new account is copied to `address_ptr` and its length
	/// to `address_len_ptr`. The constructors output buffer is copied to `output_ptr` and its
	/// length to `output_len_ptr`. The copy of the output buffer and address can be skipped by
	/// supplying the sentinel value of `SENTINEL` to `output_ptr` or `address_ptr`.
	///
	/// `value` must be at least the minimum balance. Otherwise the instantiation fails and the
	/// contract is not created.
	///
	/// # Parameters
	///
	/// - code_hash_ptr: a pointer to the buffer that contains the initializer code.
	/// - gas: how much gas to devote to the execution of the initializer code.
	/// - value_ptr: a pointer to the buffer with value, how much value to send. Should be decodable
	///   as a `T::Balance`. Traps otherwise.
	/// - input_data_ptr: a pointer to a buffer to be used as input data to the initializer code.
	/// - input_data_len: length of the input data buffer.
	/// - address_ptr: a pointer where the new account's address is copied to.
	/// - address_len_ptr: in-out pointer to where the length of the buffer is read from and the
	///   actual length is written to.
	/// - output_ptr: a pointer where the output buffer is copied to.
	/// - output_len_ptr: in-out pointer to where the length of the buffer is read from and the
	///   actual length is written to.
	/// - salt_ptr: Pointer to raw bytes used for address derivation. See `fn contract_address`.
	/// - salt_len: length in bytes of the supplied salt.
	///
	/// # Errors
	///
	/// Please consult the `ReturnCode` enum declaration for more information on those
	/// errors. Here we only note things specific to this function.
	///
	/// An error means that the account wasn't created and no address or output buffer
	/// is returned unless stated otherwise.
	///
	/// `ReturnCode::CalleeReverted`: Output buffer is returned.
	/// `ReturnCode::CalleeTrapped`
	/// `ReturnCode::TransferFailed`
	/// `ReturnCode::CodeNotFound`
	#[version(1)]
	fn seal_instantiate(
		ctx: Runtime<E: Ext>,
		code_hash_ptr: u32,
		gas: u64,
		value_ptr: u32,
		input_data_ptr: u32,
		input_data_len: u32,
		address_ptr: u32,
		address_len_ptr: u32,
		output_ptr: u32,
		output_len_ptr: u32,
		salt_ptr: u32,
		salt_len: u32,
	) -> Result<ReturnCode, TrapReason> {
		ctx.instantiate(
			code_hash_ptr,
			gas,
			value_ptr,
			input_data_ptr,
			input_data_len,
			address_ptr,
			address_len_ptr,
			output_ptr,
			output_len_ptr,
			salt_ptr,
			salt_len,
		)
	}

	/// Remove the calling account and transfer remaining balance.
	///
	/// # Deprecation
	///
	/// This is equivalent to calling the newer version of this function. The newer version
	/// drops the now unnecessary length fields.
	///
	/// # Note
	///
	/// The value `_beneficiary_len` is ignored because the encoded sizes
	/// this type is fixed through `[`MaxEncodedLen`]. The field exist for backwards
	/// compatibility. Consider switching to the newest version of this function.
	fn seal_terminate(
		ctx: Runtime<E: Ext>,
		beneficiary_ptr: u32,
		_beneficiary_len: u32,
	) -> Result<(), TrapReason> {
		ctx.terminate(beneficiary_ptr)
	}

	/// Remove the calling account and transfer remaining **free** balance.
	///
	/// This function never returns. Either the termination was successful and the
	/// execution of the destroyed contract is halted. Or it failed during the termination
	/// which is considered fatal and results in a trap + rollback.
	///
	/// - beneficiary_ptr: a pointer to the address of the beneficiary account where all where all
	///   remaining funds of the caller are transferred. Should be decodable as an `T::AccountId`.
	///   Traps otherwise.
	///
	/// # Traps
	///
	/// - The contract is live i.e is already on the call stack.
	/// - Failed to send the balance to the beneficiary.
	/// - The deletion queue is full.
	#[version(1)]
	fn seal_terminate(ctx: Runtime<E: Ext>, beneficiary_ptr: u32) -> Result<(), TrapReason> {
		ctx.terminate(beneficiary_ptr)
	}

	/// Stores the input passed by the caller into the supplied buffer.
	///
	/// The value is stored to linear memory at the address pointed to by `out_ptr`.
	/// `out_len_ptr` must point to a u32 value that describes the available space at
	/// `out_ptr`. This call overwrites it with the size of the value. If the available
	/// space at `out_ptr` is less than the size of the value a trap is triggered.
	///
	/// # Note
	///
	/// This function traps if the input was previously forwarded by a `seal_call`.
	fn seal_input(ctx: Runtime<E: Ext>, out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::InputBase)?;
		if let Some(input) = ctx.input_data.take() {
			ctx.write_sandbox_output(out_ptr, out_len_ptr, &input, false, |len| {
				Some(RuntimeCosts::CopyToContract(len))
			})?;
			ctx.input_data = Some(input);
			Ok(())
		} else {
			Err(Error::<E::T>::InputForwarded.into())
		}
	}

	/// Cease contract execution and save a data buffer as a result of the execution.
	///
	/// This function never returns as it stops execution of the caller.
	/// This is the only way to return a data buffer to the caller. Returning from
	/// execution without calling this function is equivalent to calling:
	/// ```
	/// seal_return(0, 0, 0);
	/// ```
	///
	/// The flags argument is a bitfield that can be used to signal special return
	/// conditions to the supervisor:
	/// --- lsb ---
	/// bit 0      : REVERT - Revert all storage changes made by the caller.
	/// bit [1, 31]: Reserved for future use.
	/// --- msb ---
	///
	/// Using a reserved bit triggers a trap.
	fn seal_return(
		ctx: Runtime<E: Ext>,
		flags: u32,
		data_ptr: u32,
		data_len: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::Return(data_len))?;
		Err(TrapReason::Return(ReturnData {
			flags,
			data: ctx.read_sandbox_memory(data_ptr, data_len)?,
		}))
	}

	/// Stores the address of the caller into the supplied buffer.
	///
	/// The value is stored to linear memory at the address pointed to by `out_ptr`.
	/// `out_len_ptr` must point to a u32 value that describes the available space at
	/// `out_ptr`. This call overwrites it with the size of the value. If the available
	/// space at `out_ptr` is less than the size of the value a trap is triggered.
	///
	/// If this is a top-level call (i.e. initiated by an extrinsic) the origin address of the
	/// extrinsic will be returned. Otherwise, if this call is initiated by another contract then
	/// the address of the contract will be returned. The value is encoded as T::AccountId.
	fn seal_caller(ctx: Runtime<E: Ext>, out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::Caller)?;
		Ok(ctx.write_sandbox_output(
			out_ptr,
			out_len_ptr,
			&ctx.ext.caller().encode(),
			false,
			already_charged,
		)?)
	}

	/// Checks whether a specified address belongs to a contract.
	///
	/// # Parameters
	///
	/// - account_ptr: a pointer to the address of the beneficiary account Should be decodable as an
	///   `T::AccountId`. Traps otherwise.
	///
	/// Returned value is a u32-encoded boolean: (0 = false, 1 = true).
	fn seal_is_contract(ctx: Runtime<E: Ext>, account_ptr: u32) -> Result<u32, TrapReason> {
		ctx.charge_gas(RuntimeCosts::IsContract)?;
		let address: <<E as Ext>::T as frame_system::Config>::AccountId =
			ctx.read_sandbox_memory_as(account_ptr)?;

		Ok(ctx.ext.is_contract(&address) as u32)
	}

	/// Retrieve the code hash for a specified contract address.
	///
	/// # Parameters
	///
	/// - `account_ptr`: a pointer to the address in question. Should be decodable as an
	///   `T::AccountId`. Traps otherwise.
	/// - `out_ptr`: pointer to the linear memory where the returning value is written to.
	/// - `out_len_ptr`: in-out pointer into linear memory where the buffer length is read from and
	///   the value length is written to.
	///
	/// # Errors
	///
	/// `ReturnCode::KeyNotFound`
	fn seal_code_hash(
		ctx: Runtime<E: Ext>,
		account_ptr: u32,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<ReturnCode, TrapReason> {
		ctx.charge_gas(RuntimeCosts::CodeHash)?;
		let address: <<E as Ext>::T as frame_system::Config>::AccountId =
			ctx.read_sandbox_memory_as(account_ptr)?;
		if let Some(value) = ctx.ext.code_hash(&address) {
			ctx.write_sandbox_output(
				out_ptr,
				out_len_ptr,
				&value.encode(),
				false,
				already_charged,
			)?;
			Ok(ReturnCode::Success)
		} else {
			Ok(ReturnCode::KeyNotFound)
		}
	}

	/// Retrieve the code hash of the currently executing contract.
	///
	/// # Parameters
	///
	/// - `out_ptr`: pointer to the linear memory where the returning value is written to.
	/// - `out_len_ptr`: in-out pointer into linear memory where the buffer length is read from and
	///   the value length is written to.
	fn seal_own_code_hash(
		ctx: Runtime<E: Ext>,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::OwnCodeHash)?;
		let code_hash_encoded = &ctx.ext.own_code_hash().encode();
		Ok(ctx.write_sandbox_output(
			out_ptr,
			out_len_ptr,
			code_hash_encoded,
			false,
			already_charged,
		)?)
	}

	/// Checks whether the caller of the current contract is the origin of the whole call stack.
	///
	/// Prefer this over `seal_is_contract` when checking whether your contract is being called by a
	/// contract or a plain account. The reason is that it performs better since it does not need to
	/// do any storage lookups.
	///
	/// A return value of`true` indicates that this contract is being called by a plain account
	/// and `false` indicates that the caller is another contract.
	///
	/// Returned value is a u32-encoded boolean: (0 = false, 1 = true).
	fn seal_caller_is_origin(ctx: Runtime<E: Ext>) -> Result<u32, TrapReason> {
		ctx.charge_gas(RuntimeCosts::CallerIsOrigin)?;
		Ok(ctx.ext.caller_is_origin() as u32)
	}

	/// Stores the address of the current contract into the supplied buffer.
	///
	/// The value is stored to linear memory at the address pointed to by `out_ptr`.
	/// `out_len_ptr` must point to a u32 value that describes the available space at
	/// `out_ptr`. This call overwrites it with the size of the value. If the available
	/// space at `out_ptr` is less than the size of the value a trap is triggered.
	fn seal_address(
		ctx: Runtime<E: Ext>,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::Address)?;
		Ok(ctx.write_sandbox_output(
			out_ptr,
			out_len_ptr,
			&ctx.ext.address().encode(),
			false,
			already_charged,
		)?)
	}

	/// Stores the price for the specified amount of gas into the supplied buffer.
	///
	/// The value is stored to linear memory at the address pointed to by `out_ptr`.
	/// `out_len_ptr` must point to a u32 value that describes the available space at
	/// `out_ptr`. This call overwrites it with the size of the value. If the available
	/// space at `out_ptr` is less than the size of the value a trap is triggered.
	///
	/// The data is encoded as T::Balance.
	///
	/// # Note
	///
	/// It is recommended to avoid specifying very small values for `gas` as the prices for a single
	/// gas can be smaller than one.
	fn seal_weight_to_fee(
		ctx: Runtime<E: Ext>,
		gas: u64,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<(), TrapReason> {
		let gas = Weight::from_ref_time(gas);
		ctx.charge_gas(RuntimeCosts::WeightToFee)?;
		Ok(ctx.write_sandbox_output(
			out_ptr,
			out_len_ptr,
			&ctx.ext.get_weight_price(gas).encode(),
			false,
			already_charged,
		)?)
	}

	/// Stores the amount of gas left into the supplied buffer.
	///
	/// The value is stored to linear memory at the address pointed to by `out_ptr`.
	/// `out_len_ptr` must point to a u32 value that describes the available space at
	/// `out_ptr`. This call overwrites it with the size of the value. If the available
	/// space at `out_ptr` is less than the size of the value a trap is triggered.
	///
	/// The data is encoded as Gas.
	fn seal_gas_left(
		ctx: Runtime<E: Ext>,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::GasLeft)?;
		let gas_left = &ctx.ext.gas_meter().gas_left().encode();
		Ok(ctx.write_sandbox_output(out_ptr, out_len_ptr, gas_left, false, already_charged)?)
	}

	/// Stores the **free* balance of the current account into the supplied buffer.
	///
	/// The value is stored to linear memory at the address pointed to by `out_ptr`.
	/// `out_len_ptr` must point to a u32 value that describes the available space at
	/// `out_ptr`. This call overwrites it with the size of the value. If the available
	/// space at `out_ptr` is less than the size of the value a trap is triggered.
	///
	/// The data is encoded as T::Balance.
	fn seal_balance(
		ctx: Runtime<E: Ext>,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::Balance)?;
		Ok(ctx.write_sandbox_output(
			out_ptr,
			out_len_ptr,
			&ctx.ext.balance().encode(),
			false,
			already_charged,
		)?)
	}

	/// Stores the value transferred along with this call/instantiate into the supplied buffer.
	///
	/// The value is stored to linear memory at the address pointed to by `out_ptr`.
	/// `out_len_ptr` must point to a u32 value that describes the available space at
	/// `out_ptr`. This call overwrites it with the size of the value. If the available
	/// space at `out_ptr` is less than the size of the value a trap is triggered.
	///
	/// The data is encoded as T::Balance.
	fn seal_value_transferred(
		ctx: Runtime<E: Ext>,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::ValueTransferred)?;
		Ok(ctx.write_sandbox_output(
			out_ptr,
			out_len_ptr,
			&ctx.ext.value_transferred().encode(),
			false,
			already_charged,
		)?)
	}

	/// Stores a random number for the current block and the given subject into the supplied buffer.
	///
	/// The value is stored to linear memory at the address pointed to by `out_ptr`.
	/// `out_len_ptr` must point to a u32 value that describes the available space at
	/// `out_ptr`. This call overwrites it with the size of the value. If the available
	/// space at `out_ptr` is less than the size of the value a trap is triggered.
	///
	/// The data is encoded as T::Hash.
	///
	/// # Deprecation
	///
	/// This function is deprecated. Users should migrate to the version in the "seal1" module.
	fn seal_random(
		ctx: Runtime<E: Ext>,
		subject_ptr: u32,
		subject_len: u32,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::Random)?;
		if subject_len > ctx.ext.schedule().limits.subject_len {
			return Err(Error::<E::T>::RandomSubjectTooLong.into())
		}
		let subject_buf = ctx.read_sandbox_memory(subject_ptr, subject_len)?;
		Ok(ctx.write_sandbox_output(
			out_ptr,
			out_len_ptr,
			&ctx.ext.random(&subject_buf).0.encode(),
			false,
			already_charged,
		)?)
	}

	/// Stores a random number for the current block and the given subject into the supplied buffer.
	///
	/// The value is stored to linear memory at the address pointed to by `out_ptr`.
	/// `out_len_ptr` must point to a u32 value that describes the available space at
	/// `out_ptr`. This call overwrites it with the size of the value. If the available
	/// space at `out_ptr` is less than the size of the value a trap is triggered.
	///
	/// The data is encoded as (T::Hash, T::BlockNumber).
	///
	/// # Changes from v0
	///
	/// In addition to the seed it returns the block number since which it was determinable
	/// by chain observers.
	///
	/// # Note
	///
	/// The returned seed should only be used to distinguish commitments made before
	/// the returned block number. If the block number is too early (i.e. commitments were
	/// made afterwards), then ensure no further commitments may be made and repeatedly
	/// call this on later blocks until the block number returned is later than the latest
	/// commitment.
	#[version(1)]
	fn seal_random(
		ctx: Runtime<E: Ext>,
		subject_ptr: u32,
		subject_len: u32,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::Random)?;
		if subject_len > ctx.ext.schedule().limits.subject_len {
			return Err(Error::<E::T>::RandomSubjectTooLong.into())
		}
		let subject_buf = ctx.read_sandbox_memory(subject_ptr, subject_len)?;
		Ok(ctx.write_sandbox_output(
			out_ptr,
			out_len_ptr,
			&ctx.ext.random(&subject_buf).encode(),
			false,
			already_charged,
		)?)
	}

	/// Load the latest block timestamp into the supplied buffer
	///
	/// The value is stored to linear memory at the address pointed to by `out_ptr`.
	/// `out_len_ptr` must point to a u32 value that describes the available space at
	/// `out_ptr`. This call overwrites it with the size of the value. If the available
	/// space at `out_ptr` is less than the size of the value a trap is triggered.
	fn seal_now(ctx: Runtime<E: Ext>, out_ptr: u32, out_len_ptr: u32) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::Now)?;
		Ok(ctx.write_sandbox_output(
			out_ptr,
			out_len_ptr,
			&ctx.ext.now().encode(),
			false,
			already_charged,
		)?)
	}

	/// Stores the minimum balance (a.k.a. existential deposit) into the supplied buffer.
	///
	/// The data is encoded as T::Balance.
	fn seal_minimum_balance(
		ctx: Runtime<E: Ext>,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::MinimumBalance)?;
		Ok(ctx.write_sandbox_output(
			out_ptr,
			out_len_ptr,
			&ctx.ext.minimum_balance().encode(),
			false,
			already_charged,
		)?)
	}

	/// Stores the tombstone deposit into the supplied buffer.
	///
	/// The value is stored to linear memory at the address pointed to by `out_ptr`.
	/// `out_len_ptr` must point to a u32 value that describes the available space at
	/// `out_ptr`. This call overwrites it with the size of the value. If the available
	/// space at `out_ptr` is less than the size of the value a trap is triggered.
	///
	/// # Deprecation
	///
	/// There is no longer a tombstone deposit. This function always returns 0.
	fn seal_tombstone_deposit(
		ctx: Runtime<E: Ext>,
		out_ptr: u32,
		out_len_ptr: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::Balance)?;
		let deposit = <BalanceOf<E::T>>::zero().encode();
		Ok(ctx.write_sandbox_output(out_ptr, out_len_ptr, &deposit, false, already_charged)?)
	}

	/// Was used to restore the given destination contract sacrificing the caller.
	///
	/// # Note
	///
	/// The state rent functionality was removed. This is stub only exists for
	/// backwards compatiblity
	fn seal_restore_to(
		ctx: Runtime<E: Ext>,
		_dest_ptr: u32,
		_dest_len: u32,
		_code_hash_ptr: u32,
		_code_hash_len: u32,
		_rent_allowance_ptr: u32,
		_rent_allowance_len: u32,
		_delta_ptr: u32,
		_delta_count: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::DebugMessage)?;
		Ok(())
	}

	/// Was used to restore the given destination contract sacrificing the caller.
	///
	/// # Note
	///
	/// The state rent functionality was removed. This is stub only exists for
	/// backwards compatiblity
	#[version(1)]
	fn seal_restore_to(
		ctx: Runtime<E: Ext>,
		_dest_ptr: u32,
		_code_hash_ptr: u32,
		_rent_allowance_ptr: u32,
		_delta_ptr: u32,
		_delta_count: u32,
	) -> Result<(), TrapReason> {
		ctx.charge_gas(RuntimeCosts::DebugMessage)?;
		Ok(())
	}

	/// Deposit a contract event with the data buffer and optional list of topics. There is a limit
	/// on the maximum number of topics specified by `event_topics`.
	///
	/// - topics_ptr - a pointer to the buffer of topics encoded as `Vec<T::Hash>`. The value of
	///   this is ignored if `topics_len` is set to 0. The topics list can't contain duplicates.
	/// - topics_len - the length of the topics buffer. Pass 0 if you want to pass an empty vector.
	/// - data_ptr - a pointer to a raw data buffer which will saved along the event.
	/// - data_len - the length of the data buffer.
	fn seal_deposit_event(
		ctx: Runtime<E: Ext>,
		topics_ptr: u32,
		topics_len: u32,
		data_ptr: u32,
		data_len: u32,
	) -> Result<(), TrapReason> {
		fn has_duplicates<T: Ord>(items: &mut Vec<T>) -> bool {
			// # Warning
			//
			// Unstable sorts are non-deterministic across architectures. The usage here is OK
			// because we are rejecting duplicates which removes the non determinism.
			items.sort_unstable();
			// Find any two consecutive equal elements.
			items.windows(2).any(|w| match &w {
				&[a, b] => a == b,
				_ => false,
			})
		}

		let num_topic = topics_len
			.checked_div(sp_std::mem::size_of::<TopicOf<E::T>>() as u32)
			.ok_or("Zero sized topics are not allowed")?;
		ctx.charge_gas(RuntimeCosts::DepositEvent { num_topic, len: data_len })?;
		if data_len > ctx.ext.max_value_size() {
			return Err(Error::<E::T>::ValueTooLarge.into())
		}

		let mut topics: Vec<TopicOf<<E as Ext>::T>> = match topics_len {
			0 => Vec::new(),
			_ => ctx.read_sandbox_memory_as_unbounded(topics_ptr, topics_len)?,
		};

		// If there are more than `event_topics`, then trap.
		if topics.len() > ctx.ext.schedule().limits.event_topics as usize {
			return Err(Error::<E::T>::TooManyTopics.into())
		}

		// Check for duplicate topics. If there are any, then trap.