Merge branch into fast_toString

CodeSandwich · Jul 25, 2022 · 8597e3d · CodeSandwich · Jul 25, 2022 · Amxx
2 parents 029c82e + 365e07b
commit 8597e3d
Show file tree

Hide file tree

Showing 2 changed files with 41 additions and 80 deletions.
diff --git a/contracts/utils/Strings.sol b/contracts/utils/Strings.sol
@@ -15,45 +15,47 @@ library Strings {
      */
     function toString(uint256 value) internal pure returns (string memory result) {
         unchecked {
-            if (value < 10) {
-                return string(abi.encodePacked(uint8(value + 48)));
-            }
-            uint256 length = 0;
+            uint256 length = 1;
+
+            // compute log10(value), and add it to length
             uint256 valueCopy = value;
-            if (valueCopy >= 10**63) {
+            if (valueCopy >= 10**64) {
                 valueCopy /= 10**64;
                 length += 64;
             }
-            if (valueCopy >= 10**31) {
+            if (valueCopy >= 10**32) {
                 valueCopy /= 10**32;
                 length += 32;
             }
-            if (valueCopy >= 10**15) {
+            if (valueCopy >= 10**16) {
                 valueCopy /= 10**16;
                 length += 16;
             }
-            if (valueCopy >= 10**7) {
+            if (valueCopy >= 10**8) {
                 valueCopy /= 10**8;
                 length += 8;
             }
-            if (valueCopy >= 10**3) {
+            if (valueCopy >= 10**4) {
                 valueCopy /= 10**4;
                 length += 4;
             }
-            if (valueCopy >= 10**1) {
+            if (valueCopy >= 10**2) {
                 valueCopy /= 10**2;
                 length += 2;
             }
-            if (valueCopy >= 1) {
+            if (valueCopy >= 10**1) {
                 length += 1;
             }
+            // now, length is log10(value) + 1
             result = new string(length);
             /// @solidity memory-safe-assembly
             assembly {
-                let ptr := add(result, add(length, 32))
+                let pos := add(result, 32)
+                let ptr := add(pos, length)
+
                 for {
 
-                } gt(value, 0) {
+                } gt(ptr, pos) {
 
                 } {
                     ptr := sub(ptr, 1)

diff --git a/test/utils/Strings.test.js b/test/utils/Strings.test.js
@@ -1,4 +1,4 @@
-const { constants, expectRevert } = require('@openzeppelin/test-helpers');
+const { BN, constants, expectRevert } = require('@openzeppelin/test-helpers');
 
 const { expect } = require('chai');
 
@@ -12,73 +12,32 @@ contract('Strings', function (accounts) {
   });
 
   describe('toString', function () {
-    async function testToString (input) {
-      expect(await strings.toStringDecimal(input)).to.equal(input);
+    for (const [ key, value ] of Object.entries([
+      '0',
+      '7',
+      '10',
+      '99',
+      '100',
+      '101',
+      '123',
+      '4132',
+      '12345',
+      '1234567',
+      '1234567890',
+      '123456789012345',
+      '12345678901234567890',
+      '123456789012345678901234567890',
+      '1234567890123456789012345678901234567890',
+      '12345678901234567890123456789012345678901234567890',
+      '123456789012345678901234567890123456789012345678901234567890',
+      '1234567890123456789012345678901234567890123456789012345678901234567890',
+    ].reduce((acc, value) => Object.assign(acc, { [value]: new BN(value) }), {
+      MAX_UINT256: constants.MAX_UINT256.toString(),
+    }))) {
+      it(`converts ${key}`, async function () {
+        expect(await strings.toStringDecimal(value)).to.equal(value.toString(10));
+      });
     }
-
-    it('converts 0', async function () {
-      await testToString('0');
-    });
-
-    it('converts 7', async function () {
-      await testToString('7');
-    });
-
-    it('converts 42', async function () {
-      await testToString('42');
-    });
-
-    it('converts 123', async function () {
-      await testToString('123');
-    });
-
-    it('converts 4132', async function () {
-      await testToString('4132');
-    });
-
-    it('converts 12345', async function () {
-      await testToString('12345');
-    });
-
-    it('converts 1234567', async function () {
-      await testToString('1234567');
-    });
-
-    it('converts 1234567890', async function () {
-      await testToString('1234567890');
-    });
-
-    it('converts 123456789012345', async function () {
-      await testToString('123456789012345');
-    });
-
-    it('converts 12345678901234567890', async function () {
-      await testToString('12345678901234567890');
-    });
-
-    it('converts 123456789012345678901234567890', async function () {
-      await testToString('123456789012345678901234567890');
-    });
-
-    it('converts 1234567890123456789012345678901234567890', async function () {
-      await testToString('1234567890123456789012345678901234567890');
-    });
-
-    it('converts 12345678901234567890123456789012345678901234567890', async function () {
-      await testToString('12345678901234567890123456789012345678901234567890');
-    });
-
-    it('converts 123456789012345678901234567890123456789012345678901234567890', async function () {
-      await testToString('123456789012345678901234567890123456789012345678901234567890');
-    });
-
-    it('converts 1234567890123456789012345678901234567890123456789012345678901234567890', async function () {
-      await testToString('1234567890123456789012345678901234567890123456789012345678901234567890');
-    });
-
-    it('converts MAX_UINT256', async function () {
-      await testToString(constants.MAX_UINT256.toString());
-    });
   });
 
   describe('toHexString', function () {