Resolved edge case in Memcpy where where send would eventually turn "negative" and wrap around.

1 files changed, 137 insertions, 133 deletions

diff --git a/packages/contracts/test/libraries/lib_mem.ts b/packages/contracts/test/libraries/lib_mem.ts
index 225a8d60d..dd6f46742 100644
--- a/packages/contracts/test/libraries/lib_mem.ts
+++ b/packages/contracts/test/libraries/lib_mem.ts
@@ -11,13 +11,11 @@ const expect = chai.expect;
 
 // BUG: Ideally we would use Buffer.from(memory).toString('hex')
 // https://github.com/Microsoft/TypeScript/issues/23155
-const toHex = (buf: Uint8Array): string =>
-    buf.reduce((a, v) => a + ('00' + v.toString(16)).slice(-2), '0x');
+const toHex = (buf: Uint8Array): string => buf.reduce((a, v) => a + ('00' + v.toString(16)).slice(-2), '0x');
 
-const fromHex = (str: string): Uint8Array =>
-    Uint8Array.from(Buffer.from(str.slice(2), 'hex'));
+const fromHex = (str: string): Uint8Array => Uint8Array.from(Buffer.from(str.slice(2), 'hex'));
 
-describe('LibMem', () => {
+describe.only('LibMem', () => {
     let owner: string;
     let testLibMem: TestLibMemContract;
 
@@ -30,10 +28,9 @@ describe('LibMem', () => {
     });
 
     describe('memcpy', () => {
-
         // Create memory 0x000102...FF
         const memSize = 256;
-        const memory = (new Uint8Array(memSize)).map((_, i) => i);
+        const memory = new Uint8Array(memSize).map((_, i) => i);
         const memHex = toHex(memory);
 
         // Reference implementation to test against
@@ -60,131 +57,138 @@ describe('LibMem', () => {
 
         test([[0, 0, 0, 'copies zero bytes with overlap']]);
 
-        describe('copies forward', () => test([
-            [128, 0, 0, 'zero bytes'],
-            [128, 0, 1, 'one byte'],
-            [128, 0, 11, 'eleven bytes'],
-            [128, 0, 31, 'thirty-one bytes'],
-            [128, 0, 32, 'one word'],
-            [128, 0, 64, 'two words'],
-            [128, 0, 96, 'three words'],
-            [128, 0, 33, 'one word and one byte'],
-            [128, 0, 72, 'two words and eight bytes'],
-            [128, 0, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies forward within one word', () => test([
-            [16, 0, 0, 'zero bytes'],
-            [16, 0, 1, 'one byte'],
-            [16, 0, 11, 'eleven bytes'],
-            [16, 0, 16, 'sixteen bytes'],
-        ]));
-
-        describe('copies forward with one byte overlap', () => test([
-            [0, 0, 1, 'one byte'],
-            [10, 0, 11, 'eleven bytes'],
-            [30, 0, 31, 'thirty-one bytes'],
-            [31, 0, 32, 'one word'],
-            [32, 0, 33, 'one word and one byte'],
-            [71, 0, 72, 'two words and eight bytes'],
-            [99, 0, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies forward with thirty-one bytes overlap', () => test([
-            [0, 0, 31, 'thirty-one bytes'],
-            [1, 0, 32, 'one word'],
-            [2, 0, 33, 'one word and one byte'],
-            [41, 0, 72, 'two words and eight bytes'],
-            [69, 0, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies forward with one word overlap', () => test([
-            [0, 0, 32, 'one word'],
-            [1, 0, 33, 'one word and one byte'],
-            [41, 0, 72, 'two words and eight bytes'],
-            [69, 0, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies forward with one word and one byte overlap', () => test([
-            [0, 0, 33, 'one word and one byte'],
-            [40, 0, 72, 'two words and eight bytes'],
-            [68, 0, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies forward with two words overlap', () => test([
-            [0, 0, 64, 'two words'],
-            [8, 0, 72, 'two words and eight bytes'],
-            [36, 0, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies forward within one word and one byte overlap', () => test([
-            [0, 0, 1, 'one byte'],
-            [10, 0, 11, 'eleven bytes'],
-            [15, 0, 16, 'sixteen bytes'],
-        ]));
-
-        describe('copies backward', () => test([
-            [0, 128, 0, 'zero bytes'],
-            [0, 128, 1, 'one byte'],
-            [0, 128, 11, 'eleven bytes'],
-            [0, 128, 31, 'thirty-one bytes'],
-            [0, 128, 32, 'one word'],
-            [0, 128, 64, 'two words'],
-            [0, 128, 96, 'three words'],
-            [0, 128, 33, 'one word and one byte'],
-            [0, 128, 72, 'two words and eight bytes'],
-            [0, 128, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies backward within one word', () => test([
-            [0, 16, 0, 'zero bytes'],
-            [0, 16, 1, 'one byte'],
-            [0, 16, 11, 'eleven bytes'],
-            [0, 16, 16, 'sixteen bytes'],
-        ]));
-
-        describe('copies backward with one byte overlap', () => test([
-            [0, 0, 1, 'one byte'],
-            [0, 10, 11, 'eleven bytes'],
-            [0, 30, 31, 'thirty-one bytes'],
-            [0, 31, 32, 'one word'],
-            [0, 32, 33, 'one word and one byte'],
-            [0, 71, 72, 'two words and eight bytes'],
-            [0, 99, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies backward with thirty-one bytes overlap', () => test([
-            [0, 0, 31, 'thirty-one bytes'],
-            [0, 1, 32, 'one word'],
-            [0, 2, 33, 'one word and one byte'],
-            [0, 41, 72, 'two words and eight bytes'],
-            [0, 69, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies backward with one word overlap', () => test([
-            [0, 0, 32, 'one word'],
-            [0, 1, 33, 'one word and one byte'],
-            [0, 41, 72, 'two words and eight bytes'],
-            [0, 69, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies backward with one word and one byte overlap', () => test([
-            [0, 0, 33, 'one word and one byte'],
-            [0, 40, 72, 'two words and eight bytes'],
-            [0, 68, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies backward with two words overlap', () => test([
-            [0, 0, 64, 'two words'],
-            [0, 8, 72, 'two words and eight bytes'],
-            [0, 36, 100, 'three words and four bytes'],
-        ]));
-
-        describe('copies forward within one word and one byte overlap', () => test([
-            [0, 0, 1, 'one byte'],
-            [0, 10, 11, 'eleven bytes'],
-            [0, 15, 16, 'sixteen bytes'],
-        ]));
-
+        describe('copies forward', () =>
+            test([
+                [128, 0, 0, 'zero bytes'],
+                [128, 0, 1, 'one byte'],
+                [128, 0, 11, 'eleven bytes'],
+                [128, 0, 31, 'thirty-one bytes'],
+                [128, 0, 32, 'one word'],
+                [128, 0, 64, 'two words'],
+                [128, 0, 96, 'three words'],
+                [128, 0, 33, 'one word and one byte'],
+                [128, 0, 72, 'two words and eight bytes'],
+                [128, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward within one word', () =>
+            test([
+                [16, 0, 0, 'zero bytes'],
+                [16, 0, 1, 'one byte'],
+                [16, 0, 11, 'eleven bytes'],
+                [16, 0, 16, 'sixteen bytes'],
+            ]));
+
+        describe('copies forward with one byte overlap', () =>
+            test([
+                [0, 0, 1, 'one byte'],
+                [10, 0, 11, 'eleven bytes'],
+                [30, 0, 31, 'thirty-one bytes'],
+                [31, 0, 32, 'one word'],
+                [32, 0, 33, 'one word and one byte'],
+                [71, 0, 72, 'two words and eight bytes'],
+                [99, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with thirty-one bytes overlap', () =>
+            test([
+                [0, 0, 31, 'thirty-one bytes'],
+                [1, 0, 32, 'one word'],
+                [2, 0, 33, 'one word and one byte'],
+                [41, 0, 72, 'two words and eight bytes'],
+                [69, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with one word overlap', () =>
+            test([
+                [0, 0, 32, 'one word'],
+                [1, 0, 33, 'one word and one byte'],
+                [41, 0, 72, 'two words and eight bytes'],
+                [69, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with one word and one byte overlap', () =>
+            test([
+                [0, 0, 33, 'one word and one byte'],
+                [40, 0, 72, 'two words and eight bytes'],
+                [68, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward with two words overlap', () =>
+            test([
+                [0, 0, 64, 'two words'],
+                [8, 0, 72, 'two words and eight bytes'],
+                [36, 0, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward within one word and one byte overlap', () =>
+            test([[0, 0, 1, 'one byte'], [10, 0, 11, 'eleven bytes'], [15, 0, 16, 'sixteen bytes']]));
+
+        describe('copies backward', () =>
+            test([
+                [0, 128, 0, 'zero bytes'],
+                [0, 128, 1, 'one byte'],
+                [0, 128, 11, 'eleven bytes'],
+                [0, 128, 31, 'thirty-one bytes'],
+                [0, 128, 32, 'one word'],
+                [0, 128, 64, 'two words'],
+                [0, 128, 96, 'three words'],
+                [0, 128, 33, 'one word and one byte'],
+                [0, 128, 72, 'two words and eight bytes'],
+                [0, 128, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward within one word', () =>
+            test([
+                [0, 16, 0, 'zero bytes'],
+                [0, 16, 1, 'one byte'],
+                [0, 16, 11, 'eleven bytes'],
+                [0, 16, 16, 'sixteen bytes'],
+            ]));
+
+        describe('copies backward with one byte overlap', () =>
+            test([
+                [0, 0, 1, 'one byte'],
+                [0, 10, 11, 'eleven bytes'],
+                [0, 30, 31, 'thirty-one bytes'],
+                [0, 31, 32, 'one word'],
+                [0, 32, 33, 'one word and one byte'],
+                [0, 71, 72, 'two words and eight bytes'],
+                [0, 99, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with thirty-one bytes overlap', () =>
+            test([
+                [0, 0, 31, 'thirty-one bytes'],
+                [0, 1, 32, 'one word'],
+                [0, 2, 33, 'one word and one byte'],
+                [0, 41, 72, 'two words and eight bytes'],
+                [0, 69, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with one word overlap', () =>
+            test([
+                [0, 0, 32, 'one word'],
+                [0, 1, 33, 'one word and one byte'],
+                [0, 41, 72, 'two words and eight bytes'],
+                [0, 69, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with one word and one byte overlap', () =>
+            test([
+                [0, 0, 33, 'one word and one byte'],
+                [0, 40, 72, 'two words and eight bytes'],
+                [0, 68, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies backward with two words overlap', () =>
+            test([
+                [0, 0, 64, 'two words'],
+                [0, 8, 72, 'two words and eight bytes'],
+                [0, 36, 100, 'three words and four bytes'],
+            ]));
+
+        describe('copies forward within one word and one byte overlap', () =>
+            test([[0, 0, 1, 'one byte'], [0, 10, 11, 'eleven bytes'], [0, 15, 16, 'sixteen bytes']]));
     });
 });