Merge branch 'master' into typo-fixes

Author: Amxx

.changeset/fast-beans-pull.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`Bytes`: Add a `clz` function to count the leading zero bits in a `bytes` buffer.

.changeset/whole-cats-find.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`Math`: Add a `clz` function to count the leading zero bits in a `uint256` value.

contracts/utils/Bytes.sol

@@ -128,7 +128,7 @@ library Bytes {
         return buffer;
     }
 
-    /*
+    /**
      * @dev Returns true if the two byte buffers are equal.
      */
     function equal(bytes memory a, bytes memory b) internal pure returns (bool) {
@@ -187,6 +187,20 @@ library Bytes {
         return (value >> 8) | (value << 8);
     }
 
+    /**
+     * @dev Counts the number of leading zero bits a bytes array. Returns `8 * buffer.length`
+     * if the buffer is all zeros.
+     */
+    function clz(bytes memory buffer) internal pure returns (uint256) {
+        for (uint256 i = 0; i < buffer.length; i += 32) {
+            bytes32 chunk = _unsafeReadBytesOffset(buffer, i);
+            if (chunk != bytes32(0)) {
+                return Math.min(8 * i + Math.clz(uint256(chunk)), 8 * buffer.length);
+            }
+        }
+        return 8 * buffer.length;
+    }
+
     /**
      * @dev Reads a bytes32 from a bytes array without bounds checking.
      *

contracts/utils/math/Math.sol

@@ -746,4 +746,11 @@ library Math {
     function unsignedRoundsUp(Rounding rounding) internal pure returns (bool) {
         return uint8(rounding) % 2 == 1;
     }
+
+    /**
+     * @dev Counts the number of leading zero bits in a uint256.
+     */
+    function clz(uint256 x) internal pure returns (uint256) {
+        return ternary(x == 0, 256, 255 - log2(x));
+    }
 }

foundry.toml

@@ -8,7 +8,7 @@ out = 'out'
 libs = ['node_modules', 'lib']
 test = 'test'
 cache_path  = 'cache_forge'
-fs_permissions = [{ access = "read", path = "./test/bin" }]
+fs_permissions = [{ access = "read", path = "./node_modules/hardhat-predeploy/bin" }]
 
 [fuzz]
 runs = 5000

fv-requirements.txt

@@ -1,4 +1,4 @@
 certora-cli==4.13.1
 # File uses a custom name (fv-requirements.txt) so that it isn't picked by Netlify's build
 # whose latest Python version is 0.3.8, incompatible with most recent versions of Halmos
-halmos==0.3.0
+halmos==0.3.1

hardhat.config.js

@@ -61,6 +61,7 @@ require('@nomicfoundation/hardhat-ethers');
 require('hardhat-exposed');
 require('hardhat-gas-reporter');
 require('hardhat-ignore-warnings');
+require('hardhat-predeploy');
 require('solidity-coverage');
 require('solidity-docgen');