Add RLP library

.changeset/khaki-hats-leave.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`Bytes`: Add a `nibbles` function to split each byte into two nibbles.

.changeset/lovely-cooks-add.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`RLP`: Add library for Ethereum's Recursive Length Prefix encoding/decoding.

.changeset/shaky-phones-mix.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`TrieProof`: Add library for verifying Ethereum Merkle-Patricia trie inclusion proofs.

.changeset/ten-steaks-try.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': minor
+---
+
+`Bytes`: Add an `equal` function to compare byte buffers.

.changeset/whole-cats-find.md

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

contracts/utils/Bytes.sol

@@ -99,6 +99,28 @@ library Bytes {
         return result;
     }
 
+    /// @dev Split each byte in `value` into two nibbles (4 bits each).
+    function nibbles(bytes memory value) internal pure returns (bytes memory) {
+        uint256 length = value.length;
+        bytes memory nibbles_ = new bytes(length * 2);
+        for (uint256 i = 0; i < length; i++) {
+            (nibbles_[i * 2], nibbles_[i * 2 + 1]) = (value[i] & 0xf0, value[i] & 0x0f);
+        }
+        return nibbles_;
+    }
+
+    /**
+     * @dev Returns true if the two byte buffers are equal.
+     */
+    function equal(bytes memory a, bytes memory b) internal pure returns (bool) {
+        return a.length == b.length && keccak256(a) == keccak256(b);
+    }
+
+    /// @dev Counts the number of leading zeros in a uint256.
+    function clz(uint256 x) internal pure returns (uint256) {
+        return Math.ternary(x == 0, 32, 31 - Math.log256(x));
+    }
+
     /**
      * @dev Moves the content of `buffer`, from `start` (included) to the end of `buffer` to the start of that buffer.
      *

contracts/utils/README.adoc

@@ -42,6 +42,7 @@ Miscellaneous contracts and libraries containing utility functions you can use t
  * {InteroperableAddress}: Library for formatting and parsing ERC-7930 interoperable addresses.
  * {Blockhash}: A library for accessing historical block hashes beyond the standard 256 block limit utilizing EIP-2935's historical blockhash functionality.
  * {Time}: A library that provides helpers for manipulating time-related objects, including a `Delay` type.
+ * {RLP}: Library for encoding and decoding data in Ethereum's Recursive Length Prefix format.
 
 [NOTE]
 ====
@@ -143,3 +144,5 @@ Ethereum contracts have no native concept of an interface, so applications must
 {{Blockhash}}
 
 {{Time}}
+
+{{RLP}}