Rename rounding modes and complete with fourth

.changeset/wild-rockets-rush.md

@@ -0,0 +1,5 @@
+---
+'openzeppelin-solidity': major
+---
+
+`Math`: Renamed members of `Rounding` enum, and added a new rounding mode for "away from zero".

contracts/mocks/docs/ERC4626Fees.sol

@@ -81,10 +81,10 @@ abstract contract ERC4626Fees is ERC4626 {
     }
 
     function _feeOnRaw(uint256 assets, uint256 feeBasePoint) private pure returns (uint256) {
-        return assets.mulDiv(feeBasePoint, 1e5, Math.Rounding.Up);
+        return assets.mulDiv(feeBasePoint, 1e5, Math.Rounding.Ceil);
     }
 
     function _feeOnTotal(uint256 assets, uint256 feeBasePoint) private pure returns (uint256) {
-        return assets.mulDiv(feeBasePoint, feeBasePoint + 1e5, Math.Rounding.Up);
+        return assets.mulDiv(feeBasePoint, feeBasePoint + 1e5, Math.Rounding.Ceil);
     }
 }

contracts/token/ERC20/extensions/ERC4626.sol

@@ -119,12 +119,12 @@ abstract contract ERC4626 is ERC20, IERC4626 {
 
     /** @dev See {IERC4626-convertToShares}. */
     function convertToShares(uint256 assets) public view virtual returns (uint256) {
-        return _convertToShares(assets, Math.Rounding.Down);
+        return _convertToShares(assets, Math.Rounding.Floor);
     }
 
     /** @dev See {IERC4626-convertToAssets}. */
     function convertToAssets(uint256 shares) public view virtual returns (uint256) {
-        return _convertToAssets(shares, Math.Rounding.Down);
+        return _convertToAssets(shares, Math.Rounding.Floor);
     }
 
     /** @dev See {IERC4626-maxDeposit}. */
@@ -139,7 +139,7 @@ abstract contract ERC4626 is ERC20, IERC4626 {
 
     /** @dev See {IERC4626-maxWithdraw}. */
     function maxWithdraw(address owner) public view virtual returns (uint256) {
-        return _convertToAssets(balanceOf(owner), Math.Rounding.Down);
+        return _convertToAssets(balanceOf(owner), Math.Rounding.Floor);
     }
 
     /** @dev See {IERC4626-maxRedeem}. */
@@ -149,22 +149,22 @@ abstract contract ERC4626 is ERC20, IERC4626 {
 
     /** @dev See {IERC4626-previewDeposit}. */
     function previewDeposit(uint256 assets) public view virtual returns (uint256) {
-        return _convertToShares(assets, Math.Rounding.Down);
+        return _convertToShares(assets, Math.Rounding.Floor);
     }
 
     /** @dev See {IERC4626-previewMint}. */
     function previewMint(uint256 shares) public view virtual returns (uint256) {
-        return _convertToAssets(shares, Math.Rounding.Up);
+        return _convertToAssets(shares, Math.Rounding.Ceil);
     }
 
     /** @dev See {IERC4626-previewWithdraw}. */
     function previewWithdraw(uint256 assets) public view virtual returns (uint256) {
-        return _convertToShares(assets, Math.Rounding.Up);
+        return _convertToShares(assets, Math.Rounding.Ceil);
     }
 
     /** @dev See {IERC4626-previewRedeem}. */
     function previewRedeem(uint256 shares) public view virtual returns (uint256) {
-        return _convertToAssets(shares, Math.Rounding.Down);
+        return _convertToAssets(shares, Math.Rounding.Floor);
     }
 
     /** @dev See {IERC4626-deposit}. */

contracts/utils/math/Math.sol

@@ -13,9 +13,10 @@ library Math {
     error MathOverflowedMulDiv();
 
     enum Rounding {
-        Down, // Toward negative infinity
-        Up, // Toward infinity
-        Zero // Toward zero
+        Floor, // Toward negative infinity
+        Ceil, // Toward positive infinity
+        Trunc, // Toward zero
+        Expand // Away from zero
     }
 
     /**
@@ -206,7 +207,7 @@ library Math {
      */
     function mulDiv(uint256 x, uint256 y, uint256 denominator, Rounding rounding) internal pure returns (uint256) {
         uint256 result = mulDiv(x, y, denominator);
-        if (rounding == Rounding.Up && mulmod(x, y, denominator) > 0) {
+        if (unsignedRoundsUp(rounding) && mulmod(x, y, denominator) > 0) {
             result += 1;
         }
         return result;
@@ -256,7 +257,7 @@ library Math {
     function sqrt(uint256 a, Rounding rounding) internal pure returns (uint256) {
         unchecked {
             uint256 result = sqrt(a);
-            return result + (rounding == Rounding.Up && result * result < a ? 1 : 0);
+            return result + (unsignedRoundsUp(rounding) && result * result < a ? 1 : 0);
         }
     }
 
@@ -309,7 +310,7 @@ library Math {
     function log2(uint256 value, Rounding rounding) internal pure returns (uint256) {
         unchecked {
             uint256 result = log2(value);
-            return result + (rounding == Rounding.Up && 1 << result < value ? 1 : 0);
+            return result + (unsignedRoundsUp(rounding) && 1 << result < value ? 1 : 0);
         }
     }
 
@@ -358,7 +359,7 @@ library Math {
     function log10(uint256 value, Rounding rounding) internal pure returns (uint256) {
         unchecked {
             uint256 result = log10(value);
-            return result + (rounding == Rounding.Up && 10 ** result < value ? 1 : 0);
+            return result + (unsignedRoundsUp(rounding) && 10 ** result < value ? 1 : 0);
         }
     }
 
@@ -401,7 +402,11 @@ library Math {
     function log256(uint256 value, Rounding rounding) internal pure returns (uint256) {
         unchecked {
             uint256 result = log256(value);
-            return result + (rounding == Rounding.Up && 1 << (result << 3) < value ? 1 : 0);
+            return result + (unsignedRoundsUp(rounding) && 1 << (result << 3) < value ? 1 : 0);
         }
     }
+
+    function unsignedRoundsUp(Rounding rounding) internal pure returns (bool) {
+        return uint8(rounding) % 2 == 1;
+    }
 }

test/helpers/enums.js

@@ -6,6 +6,6 @@ module.exports = {
   Enum,
   ProposalState: Enum('Pending', 'Active', 'Canceled', 'Defeated', 'Succeeded', 'Queued', 'Expired', 'Executed'),
   VoteType: Enum('Against', 'For', 'Abstain'),
-  Rounding: Enum('Down', 'Up', 'Zero'),
+  Rounding: Enum('Floor', 'Ceil', 'Trunc', 'Expand'),
   OperationState: Enum('Unset', 'Waiting', 'Ready', 'Done'),
 };

test/utils/math/Math.t.sol

@@ -31,12 +31,12 @@ contract MathTest is Test {
 
         // square of result is bigger than input
         if (_squareBigger(result, input)) {
-            assertTrue(rounding == Math.Rounding.Up);
+            assertTrue(Math.unsignedRoundsUp(rounding));
             assertTrue(_squareSmaller(result - 1, input));
         }
         // square of result is smaller than input
         else if (_squareSmaller(result, input)) {
-            assertFalse(rounding == Math.Rounding.Up);
+            assertFalse(Math.unsignedRoundsUp(rounding));
             assertTrue(_squareBigger(result + 1, input));
         }
         // input is perfect square
@@ -63,10 +63,10 @@ contract MathTest is Test {
         if (input == 0) {
             assertEq(result, 0);
         } else if (_powerOf2Bigger(result, input)) {
-            assertTrue(rounding == Math.Rounding.Up);
+            assertTrue(Math.unsignedRoundsUp(rounding));
             assertTrue(_powerOf2Smaller(result - 1, input));
         } else if (_powerOf2Smaller(result, input)) {
-            assertFalse(rounding == Math.Rounding.Up);
+            assertFalse(Math.unsignedRoundsUp(rounding));
             assertTrue(_powerOf2Bigger(result + 1, input));
         } else {
             assertEq(2 ** result, input);
@@ -90,10 +90,10 @@ contract MathTest is Test {
         if (input == 0) {
             assertEq(result, 0);
         } else if (_powerOf10Bigger(result, input)) {
-            assertTrue(rounding == Math.Rounding.Up);
+            assertTrue(Math.unsignedRoundsUp(rounding));
             assertTrue(_powerOf10Smaller(result - 1, input));
         } else if (_powerOf10Smaller(result, input)) {
-            assertFalse(rounding == Math.Rounding.Up);
+            assertFalse(Math.unsignedRoundsUp(rounding));
             assertTrue(_powerOf10Bigger(result + 1, input));
         } else {
             assertEq(10 ** result, input);
@@ -117,10 +117,10 @@ contract MathTest is Test {
         if (input == 0) {
             assertEq(result, 0);
         } else if (_powerOf256Bigger(result, input)) {
-            assertTrue(rounding == Math.Rounding.Up);
+            assertTrue(Math.unsignedRoundsUp(rounding));
             assertTrue(_powerOf256Smaller(result - 1, input));
         } else if (_powerOf256Smaller(result, input)) {
-            assertFalse(rounding == Math.Rounding.Up);
+            assertFalse(Math.unsignedRoundsUp(rounding));
             assertTrue(_powerOf256Bigger(result + 1, input));
         } else {
             assertEq(256 ** result, input);