Add Base58 library

Author: Amxx

.changeset/loose-lamps-bake.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`Base58`: Add a library for encoding and decoding bytes buffers into base58 strings.

contracts/utils/Base58.sol

@@ -0,0 +1,135 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.24;
+
+import {Bytes} from "./Bytes.sol";
+
+/**
+ * @dev Provides a set of functions to operate with Base58 strings.
+ *
+ * Based on the original https://github.com/storyicon/base58-solidity/commit/807428e5174e61867e4c606bdb26cba58a8c5cb1[implementation of storyicon] (MIT).
+ */
+library Base58 {
+    using Bytes for bytes;
+
+    string internal constant _TABLE = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz";
+
+    function encode(bytes memory data) internal pure returns (string memory) {
+        return string(_encode(data));
+    }
+
+    function decode(string memory data) internal pure returns (bytes memory) {
+        return _decode(bytes(data));
+    }
+
+    function _encode(bytes memory data) private pure returns (bytes memory) {
+        unchecked {
+            uint256 dataCLZ = _countLeading(data, 0x00);
+            uint256 slotLength = dataCLZ + ((data.length - dataCLZ) * 8351) / 6115 + 1;
+
+            bytes memory slot = new bytes(slotLength);
+            uint256 end = slotLength;
+            for (uint256 i = 0; i < data.length; i++) {
+                uint256 ptr = slotLength;
+                for (uint256 carry = _mload8i(data, i); ptr > end || carry != 0; --ptr) {
+                    carry += 256 * _mload8i(slot, ptr - 1);
+                    _mstore8i(slot, ptr - 1, uint8(carry % 58));
+                    carry /= 58;
+                }
+                end = ptr;
+            }
+
+            uint256 slotCLZ = _countLeading(slot, 0x00);
+            uint256 resultLength = slotLength + dataCLZ - slotCLZ;
+
+            bytes memory cache = bytes(_TABLE);
+            for (uint256 i = 0; i < resultLength; ++i) {
+                uint256 idx = _mload8i(slot, i + slotCLZ - dataCLZ);
+                bytes1 c = _mload8(cache, idx);
+                _mstore8(slot, i, c);
+            }
+
+            assembly ("memory-safe") {
+                mstore(slot, resultLength)
+            }
+
+            return slot;
+        }
+    }
+
+    function _decode(bytes memory data) private pure returns (bytes memory) {
+        unchecked {
+            uint256 b58Length = data.length;
+
+            uint256 size = 2 * ((b58Length * 8351) / 6115 + 1);
+            bytes memory binu = new bytes(size);
+
+            bytes memory cache = bytes(_TABLE);
+            uint32[] memory outi = new uint32[]((b58Length + 3) / 4);
+            for (uint256 i = 0; i < data.length; i++) {
+                bytes1 r = _mload8(data, i);
+                uint256 c = cache.indexOf(r); // can we avoid the loop here ?
+                require(c != type(uint256).max, "invalid base58 digit");
+                for (uint256 k = outi.length; k > 0; --k) {
+                    uint256 t = uint64(outi[k - 1]) * 58 + c;
+                    c = t >> 32;
+                    outi[k - 1] = uint32(t & 0xffffffff);
+                }
+            }
+
+            uint256 ptr = 0;
+            uint256 mask = ((b58Length - 1) % 4) + 1;
+            for (uint256 j = 0; j < outi.length; ++j) {
+                while (mask > 0) {
+                    --mask;
+                    _mstore8(binu, ptr, bytes1(uint8(outi[j] >> (8 * mask))));
+                    ptr++;
+                }
+                mask = 4;
+            }
+
+            uint256 dataCLZ = _countLeading(data, 0x31);
+            for (uint256 msb = dataCLZ; msb < binu.length; ++msb) {
+                if (_mload8(binu, msb) != 0x00) {
+                    return binu.slice(msb - dataCLZ, ptr);
+                }
+            }
+            return binu.slice(0, ptr);
+        }
+    }
+
+    function _mload8(bytes memory buffer, uint256 offset) private pure returns (bytes1 value) {
+        // This is not memory safe in the general case, but all calls to this private function are within bounds.
+        assembly ("memory-safe") {
+            value := mload(add(add(buffer, 0x20), offset))
+        }
+    }
+
+    function _mload8i(bytes memory buffer, uint256 offset) private pure returns (uint8 value) {
+        // This is not memory safe in the general case, but all calls to this private function are within bounds.
+        assembly ("memory-safe") {
+            value := shr(248, mload(add(add(buffer, 0x20), offset)))
+        }
+    }
+
+    function _mstore8(bytes memory buffer, uint256 offset, bytes1 value) private pure {
+        // This is not memory safe in the general case, but all calls to this private function are within bounds.
+        assembly ("memory-safe") {
+            mstore8(add(add(buffer, 0x20), offset), shr(248, value))
+        }
+    }
+
+    function _mstore8i(bytes memory buffer, uint256 offset, uint8 value) private pure {
+        // This is not memory safe in the general case, but all calls to this private function are within bounds.
+        assembly ("memory-safe") {
+            mstore8(add(add(buffer, 0x20), offset), value)
+        }
+    }
+
+    function _countLeading(bytes memory buffer, bytes1 el) private pure returns (uint256) {
+        uint256 length = buffer.length;
+        uint256 i = 0;
+        while (i < length && _mload8(buffer, i) == el) ++i;
+        return i;
+    }
+}

test/utils/Base58.t.sol

@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.20;
+
+import {Test} from "forge-std/Test.sol";
+import {Base58} from "@openzeppelin/contracts/utils/Base58.sol";
+
+contract Base58Test is Test {
+    function testEncodeDecodeEmpty() external pure {
+        assertEq(Base58.decode(Base58.encode("")), "");
+    }
+
+    function testEncodeDecode(bytes memory input) external pure {
+        assertEq(Base58.decode(Base58.encode(input)), input);
+    }
+}

test/utils/Base58.test.js

@@ -0,0 +1,26 @@
+const { ethers } = require('hardhat');
+const { expect } = require('chai');
+const { loadFixture } = require('@nomicfoundation/hardhat-network-helpers');
+
+async function fixture() {
+  const mock = await ethers.deployContract('$Base58');
+  return { mock };
+}
+
+describe('Base58', function () {
+  beforeEach(async function () {
+    Object.assign(this, await loadFixture(fixture));
+  });
+
+  describe('base58', function () {
+    for (const length of [0, 1, 2, 3, 4, 32, 42, 128, 384]) // 512 runs out of gas
+      it(`Encode/Decode buffer of length ${length}`, async function () {
+        const buffer = ethers.randomBytes(length);
+        const hex = ethers.hexlify(buffer);
+        const b58 = ethers.encodeBase58(buffer);
+
+        expect(await this.mock.$encode(hex)).to.equal(b58);
+        expect(await this.mock.$decode(b58)).to.equal(hex);
+      });
+  });
+});

test/utils/Base64.test.js

@@ -11,7 +11,7 @@ async function fixture() {
   return { mock };
 }
 
-describe('Strings', function () {
+describe('Base64', function () {
   beforeEach(async function () {
     Object.assign(this, await loadFixture(fixture));
   });