From 7c5beafa308bb7b80a8fabf105ce4cd35415c558 Mon Sep 17 00:00:00 2001
From: dil <contact@martinstuessy.com>
Date: Sun, 18 Jul 2021 00:31:55 +0100
Subject: [PATCH 1/2] Support solidity 0.8.0

https://docs.soliditylang.org/en/breaking/080-breaking-changes.html
---
 src/strings.sol | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/strings.sol b/src/strings.sol
index b449645a..4ad389b6 100644
--- a/src/strings.sol
+++ b/src/strings.sol
@@ -34,7 +34,7 @@
  *      corresponding to the left and right parts of the string.
  */
 
-pragma solidity ^0.4.14;
+pragma solidity ^0.8.0;
 
 library strings {
     struct slice {
@@ -83,23 +83,23 @@ library strings {
         uint ret;
         if (self == 0)
             return 0;
-        if (self & 0xffffffffffffffffffffffffffffffff == 0) {
+        if (uint(self) & 0xffffffffffffffffffffffffffffffff == 0) {
             ret += 16;
             self = bytes32(uint(self) / 0x100000000000000000000000000000000);
         }
-        if (self & 0xffffffffffffffff == 0) {
+        if (uint(self) & 0xffffffffffffffff == 0) {
             ret += 8;
             self = bytes32(uint(self) / 0x10000000000000000);
         }
-        if (self & 0xffffffff == 0) {
+        if (uint(self) & 0xffffffff == 0) {
             ret += 4;
             self = bytes32(uint(self) / 0x100000000);
         }
-        if (self & 0xffff == 0) {
+        if (uint(self) & 0xffff == 0) {
             ret += 2;
             self = bytes32(uint(self) / 0x10000);
         }
-        if (self & 0xff == 0) {
+        if (uint(self) & 0xff == 0) {
             ret += 1;
         }
         return 32 - ret;
@@ -211,7 +211,7 @@ library strings {
             }
             if (a != b) {
                 // Mask out irrelevant bytes and check again
-                uint256 mask = uint256(-1); // 0xffff...
+                uint256 mask = type(uint256).max; // 0xffff...
                 if(shortest < 32) {
                   mask = ~(2 ** (8 * (32 - shortest + idx)) - 1);
                 }
@@ -702,7 +702,7 @@ library strings {
         uint retptr;
         assembly { retptr := add(ret, 32) }
 
-        for(i = 0; i < parts.length; i++) {
+        for(uint i = 0; i < parts.length; i++) {
             memcpy(retptr, parts[i]._ptr, parts[i]._len);
             retptr += parts[i]._len;
             if (i < parts.length - 1) {

From d6f6961f22a0a15ac74aa43851cf3d8ce54af1f2 Mon Sep 17 00:00:00 2001
From: dil <contact@martinstuessy.com>
Date: Sun, 18 Jul 2021 00:53:57 +0100
Subject: [PATCH 2/2] unchecked arithmetic to preserve previous behavior

---
 src/strings.sol | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/strings.sol b/src/strings.sol
index 4ad389b6..cc47f3fc 100644
--- a/src/strings.sol
+++ b/src/strings.sol
@@ -215,9 +215,11 @@ library strings {
                 if(shortest < 32) {
                   mask = ~(2 ** (8 * (32 - shortest + idx)) - 1);
                 }
-                uint256 diff = (a & mask) - (b & mask);
-                if (diff != 0)
-                    return int(diff);
+                unchecked {
+                    uint256 diff = (a & mask) - (b & mask);
+                    if (diff != 0)
+                        return int(diff);
+                }
             }
             selfptr += 32;
             otherptr += 32;