Count Transfer Manager

Introduced in	1.0.0
Contract name	CountTransferManager.sol
Type	Transfer Manager Module
Compatible Protocol Version	^3.0.0

How it works

This contract is a transfer manager for limiting the maximum number of concurrent token holders. Note : The Count TM allowed an investor to transfer all their tokens to another address when the limit was naturally reached (no. Of investors = limit) but it did not allow this to happen when the number of investors became more than the limit by force transfer. When a maximum holder amount is reached, one of the original holders can transfer all his tokens to a new holder (not in the count list) and then the original holder will be removed.

Key functionalities (as defined in the Smart Contract)

Initialization

This function is used to initialize the variables on the entire contract

    /**
     * @notice Used to initialize the variables of the contract
     * @param _maxHolderCount Maximum no. of holders this module allows the SecurityToken to have
     */
    function configure(uint256 _maxHolderCount) public onlyFactory

Transfer Restriction

This function is used to verify the transfer transaction and prevent a transfer if it passes the allowed amount of the token holder's limit.

    /** 
     * @notice Used to verify the transfer transaction and prevent a transfer if it passes the allowed amount of token holders
     * @param _from Address of the sender
     * @param _to Address of the receiver
     * @param _amount Amount to send
     */
    function executeTransfer(
        address _from,
        address _to,
        uint256 _amount,
        bytes calldata /*_data*/
    )
        external
        returns(Result)

VerifyTransfer

A stateless function that helps to validate the transaction without actually transferring the tokens.

  /**
   * @notice Used to verify the transfer transaction and prevent a transfer if it passes the allowed amount of token holders
   * @dev module.verifyTransfer is called by SecToken.canTransfer and does not receive the updated holderCount therefore
   * verifyTransfer has to manually account for pot. token holder changes (by mimicking TokenLib.adjustInvestorCount).
   * module.executeTransfer is called by SecToken.transfer|issue|others and receives an updated holderCount 
   * as sectoken calls TokenLib.adjustInvestorCount before executeTransfer.
   * @param _from Address of the sender
   * @param _to Address of the receiver
   * @param _amount Amount to send
   */
  function verifyTransfer(
      address _from,
      address _to,
      uint256 _amount,
      bytes memory /* _data */
  )
    public
    view
    returns(Result, bytes32)

ChangeHolderCount

This function allows the issuer to set the cap for the number of token holders there can be for an STO.

   /**
    * @notice Sets the cap for the amount of token holders there can be
    * @param _maxHolderCount is the new maximum amount of token holders
    */
    function changeHolderCount(uint256 _maxHolderCount) public withPerm(ADMIN)