Store small byte arrays and strings in storage in one slot with their

length.
2023-10-03 13:03:40 +00:00 · 2015-10-02 13:12:23 +02:00
parent cae8db989a
commit da408640ca
5 changed files with 339 additions and 50 deletions
@@ -5354,6 +5354,116 @@ BOOST_AUTO_TEST_CASE(fixed_arrays_as_return_type)
 	);
 }

+BOOST_AUTO_TEST_CASE(short_strings)
+{
+	// This test verifies that the byte array encoding that combines length and data works
+	// correctly.
+	char const* sourceCode = R"(
+		contract A {
+			bytes public data1 = "123";
+			bytes data2;
+			function lengthChange() returns (uint)
+			{
+				// store constant in short and long string
+				data1 = "123";
+				if (!equal(data1, "123")) return 1;
+				data2 = "12345678901234567890123456789012345678901234567890a";
+				if (data2[17] != "8") return 3;
+				if (data2.length != 51) return 4;
+				if (data2[data2.length - 1] != "a") return 5;
+				// change length: short -> short
+				data1.length = 5;
+				if (data1.length != 5) return 6;
+				data1[4] = "4";
+				if (data1[0] != "1") return 7;
+				if (data1[4] != "4") return 8;
+				// change length: short -> long
+				data1.length = 80;
+				if (data1.length != 80) return 9;
+				data1.length = 70;
+				if (data1.length != 70) return 9;
+				if (data1[0] != "1") return 10;
+				if (data1[4] != "4") return 11;
+				for (uint i = 0; i < data1.length; i ++)
+					data1[i] = byte(i * 3);
+				if (data1[4] != 4 * 3) return 12;
+				if (data1[67] != 67 * 3) return 13;
+				// change length: long -> short
+				data1.length = 22;
+				if (data1.length != 22) return 14;
+				if (data1[21] != byte(21 * 3)) return 15;
+				if (data1[2] != 2 * 3) return 16;
+				// change length: short -> shorter
+				data1.length = 19;
+				if (data1.length != 19) return 17;
+				if (data1[7] != byte(7 * 3)) return 18;
+				// and now again to original size
+				data1.length = 22;
+				if (data1.length != 22) return 19;
+				if (data1[21] != 0) return 20;
+				data1.length = 0;
+				data2.length = 0;
+			}
+			function copy() returns (uint) {
+				bytes memory x = "123";
+				bytes memory y = "012345678901234567890123456789012345678901234567890123456789";
+				bytes memory z = "1234567";
+				data1 = x;
+				data2 = y;
+				if (!equal(data1, x)) return 1;
+				if (!equal(data2, y)) return 2;
+				// lengthen
+				data1 = y;
+				if (!equal(data1, y)) return 3;
+				// shorten
+				data1 = x;
+				if (!equal(data1, x)) return 4;
+				// change while keeping short
+				data1 = z;
+				if (!equal(data1, z)) return 5;
+				// copy storage -> storage
+				data1 = x;
+				data2 = y;
+				// lengthen
+				data1 = data2;
+				if (!equal(data1, y)) return 6;
+				// shorten
+				data1 = x;
+				data2 = data1;
+				if (!equal(data2, x)) return 7;
+				bytes memory c = data2;
+				data1 = c;
+				if (!equal(data1, x)) return 8;
+				data1 = "";
+				data2 = "";
+			}
+			function deleteElements() returns (uint) {
+				data1 = "01234";
+				delete data1[2];
+				if (data1[2] != 0) return 1;
+				if (data1[0] != "0") return 2;
+				if (data1[3] != "3") return 3;
+				delete data1;
+				if (data1.length != 0) return 4;
+			}
+
+			function equal(bytes storage a, bytes memory b) internal returns (bool) {
+				if (a.length != b.length) return false;
+				for (uint i = 0; i < a.length; ++i) if (a[i] != b[i]) return false;
+				return true;
+			}
+		}
+	)";
+	compileAndRun(sourceCode, 0, "A");
+	BOOST_CHECK(callContractFunction("data1()") == encodeDyn(string("123")));
+	BOOST_CHECK(callContractFunction("lengthChange()") == encodeArgs(u256(0)));
+	BOOST_CHECK(m_state.storage(m_contractAddress).empty());
+	BOOST_CHECK(callContractFunction("deleteElements()") == encodeArgs(u256(0)));
+	BOOST_CHECK(m_state.storage(m_contractAddress).empty());
+	BOOST_CHECK(callContractFunction("copy()") == encodeArgs(u256(0)));
+	BOOST_CHECK(m_state.storage(m_contractAddress).empty());
+}
+
 BOOST_AUTO_TEST_CASE(calldata_offset)
 {
 	// This tests a specific bug that was caused by not using the correct memory offset in the