Add library to handle bytes memory slices

contracts/libraries/BytesMemory.sol

@@ -0,0 +1,45 @@
+// SPDX-License-Identifier: MIT
+
+pragma solidity ^0.8.0;
+
+library BytesMemory {
+    error OutOfBounds();
+
+    struct Slice {
+        uint256 pointer;
+        uint256 length;
+    }
+
+    function wrap(bytes memory data) internal pure returns(Slice memory) {
+        uint256 pointer;
+        assembly ("memory-safe") { // solhint-disable-line no-inline-assembly
+            pointer := add(data, 0x20)
+        }
+
+        return Slice({
+            pointer: pointer,
+            length: data.length
+        });
+    }
+
+    function slice(Slice memory data, uint256 offset, uint256 size) internal pure returns(Slice memory) {
+        if (offset + size > data.length) revert OutOfBounds();
+
+        return Slice({
+            pointer: data.pointer + offset,
+            length: size
+        });
+    }
+
+    function unwrap(Slice memory piece) internal view returns(bytes memory ret) {
+        uint256 pointer = piece.pointer;
+        uint256 length = piece.length;
+        assembly ("memory-safe") { // solhint-disable-line no-inline-assembly
+            ret := mload(0x40)
+            mstore(0x40, add(0x20, length))
+            mstore(ret, length)
+
+            pop(staticcall(gas(), 0x04, pointer, length, add(ret, 0x20), length))
+        }
+    }
+}