2_特殊特性

地址注册

每条Arbitrum链都包含了原生的、预编译的Address Table Registry合约。该合约允许用户注册一个地址，并将其映射至某些索引上，可用来检索地址，以节省calldata字节。

接口如下：

  2. /** @title Precompiled contract that exists in every Arbitrum chain at 0x0000000000000000000000000000000000000066.
  3. * Allows registering / retrieving addresses at uint indices, saving calldata.
  4. */
  5. interface ArbAddressTable {
  6.     /**
  7.     * @notice Register an address in the address table
  8.     * @param addr address to register
  9.     * @return index of the address (existing index, or newly created index if not already registered)
  10.     */
  11.     function register(address addr) external returns(uint);
  13.     /**
  14.     * @param addr address to lookup
  15.     * @return index of an address in the address table (revert if address isn't in the table)
  16.     */
  17.     function lookup(address addr) external view returns(uint);
  19.     /**
  20.     * @notice Check whether an address exists in the address table
  21.     * @param addr address to check for presence in table
  22.     * @return true if address is in table
  23.     */
  24.     function addressExists(address addr) external view returns(bool);
  26.     /**
  27.     * @return size of address table (= first unused index)
  28.      */
  29.     function size() external view returns(uint);
  31.     /**
  32.     * @param index index to lookup address
  33.     * @return address at a given index in address table (revert if index is beyond end of table)
  34.     */
  35.     function lookupIndex(uint index) external view returns(address);
  37.     /**
  38.     * @notice read a compressed address from a bytes buffer
  39.     * @param buf bytes buffer containing an address
  40.     * @param offset offset of target address
  41.     * @return resulting address and updated offset into the buffer (revert if buffer is too short)
  42.     */
  43.     function decompress(bytes calldata buf, uint offset) external pure returns(address, uint);
  45.     /**
  46.     * @notice compress an address and return the result
  47.     * @param addr address to compress
  48.     * @return compressed address bytes
  49.     */
  50.     function compress(address addr) external returns(bytes memory);
  51. }

用例请见Arbiswap Demo。

参数序列化

一般来说，L1的calldata是Arbitrum交易的主要燃气成本。所以如果你想在Arbitrum上优化合约的燃气成本，可以尽量减少calldata的使用。

对大部分合约来说，可接受的一种方法是，将函数的参数替换为序列化的字节数组，再让合约对数据进行反序列化。

arb-ts中有序列化的方法（以及与Address Table合约互动的方法）。

用例请见Arbiswap Demo：

预编译合约

为实现特定功能，Arbitrum有几个预编译合约：

BLS签名

即将到来！ 1_总览 3_Solidity支持