Compressed BigInteger format (NeoVM 3) (#173)

* compressed biginteger * PUSHBYTES0 testing * closes #170 * simplify * back to PUSH0 * cat int(0) with empty bytearray * optimize
neo-project · Jun 15, 2019 · b4382aa · b4382aa
1 parent 1282c92
commit b4382aa
Show file tree

Hide file tree

Showing 4 changed files with 116 additions and 3 deletions.
diff --git a/src/neo-vm/OpCode.cs b/src/neo-vm/OpCode.cs
@@ -4,7 +4,9 @@ public enum OpCode : byte
     {
         // Constants
         /// <summary>
-        /// An empty array of bytes is pushed onto the stack.
+        /// An empty array of bytes is pushed onto the stack. 
+        /// This is equivalent to pushing Integer zero to the stack.
+        /// This is equivalent to pushing Boolean false to the stack.
         /// </summary>
         PUSH0 = 0x00,
         PUSHF = PUSH0,

diff --git a/src/neo-vm/Types/Integer.cs b/src/neo-vm/Types/Integer.cs
@@ -5,6 +5,8 @@ namespace Neo.VM.Types
 {
     public class Integer : StackItem
     {
+        private static readonly byte[] ZeroBytes = new byte[0];
+
         private BigInteger value;
 
         public Integer(BigInteger value)
@@ -41,14 +43,14 @@ public override bool GetBoolean()
 
         public override byte[] GetByteArray()
         {
-            return value.ToByteArray();
+            return value.IsZero ? ZeroBytes : value.ToByteArray();
         }
 
         private int _length = -1;
         public override int GetByteLength()
         {
             if (_length == -1)
-                _length = value.ToByteArray().Length;
+                _length = GetByteArray().Length;
             return _length;
         }
     }

diff --git a/tests/neo-vm.Tests/Tests/OpCodes/Push/PUSH0.json b/tests/neo-vm.Tests/Tests/OpCodes/Push/PUSH0.json
@@ -0,0 +1,55 @@
+{
+    "category": "Push",
+    "name": "PUSH0",
+    "tests":
+    [
+        {
+            "name": "Good definition",
+            "script": "0x00",
+            "steps":
+            [
+                {
+                    "actions":
+                    [
+                        "StepInto"
+                    ],
+                    "result":
+                    {
+                        "state": "Break",
+                        "invocationStack":
+                        [
+                            {
+                                "instructionPointer": 1,
+                                "nextInstruction": "RET",
+                                "evaluationStack":
+                                [
+                                    {
+                                        "type": "ByteArray",
+                                        "value": ""
+                                    }
+                                ]
+                            }
+                        ]
+                    }
+                },
+                {
+                    "actions":
+                    [
+                        "StepInto"
+                    ],
+                    "result":
+                    {
+                        "state": "Halt",
+                        "resultStack":
+                        [
+                            {
+                                "type": "ByteArray",
+                                "value": ""
+                            }
+                        ]
+                    }
+                }
+            ]
+        }
+    ]
+}
diff --git a/tests/neo-vm.Tests/Tests/OpCodes/Splice/CAT.json b/tests/neo-vm.Tests/Tests/OpCodes/Splice/CAT.json
@@ -161,6 +161,60 @@
                     }
                 }
             ]
+        },
+        {
+            "name": "CAT int(0) with empty ByteArray",
+            "script": "0x518C007E",
+            "steps":
+            [
+                {
+                    "actions":
+                    [
+                        "StepInto",
+                        "StepInto",
+                        "StepInto"
+                    ],
+                    "result":
+                    {
+                        "state": "Break",
+                        "invocationStack":
+                        [
+                            {
+                                "instructionPointer": 3,
+                                "nextInstruction": "CAT",
+                                "evaluationStack":
+                                [
+                                    {
+                                        "type": "ByteArray",
+                                        "value": ""
+                                    },
+                                    {
+                                        "type": "Integer",
+                                        "value": 0
+                                    }
+                                ]
+                            }
+                        ]
+                    }
+                },
+                {
+                    "actions":
+                    [
+                        "Execute"
+                    ],
+                    "result":
+                    {
+                        "state": "Halt",
+                        "resultStack":
+                        [
+                            {
+                                "type": "ByteArray",
+                                "value": ""
+                            }
+                        ]
+                    }
+                }
+            ]
         }
     ]
 }