From 6c8c18f2a01cca565313d858654b42498359ab3a Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Sun, 20 Aug 2017 12:52:35 -0700
Subject: [PATCH] opcode: improve perf of opcode.from methods.

---
 lib/script/opcode.js | 183 ++++++++++++++++++-------------------------
 1 file changed, 75 insertions(+), 108 deletions(-)

diff --git a/lib/script/opcode.js b/lib/script/opcode.js
index 98c1c107..1f7a1652 100644
--- a/lib/script/opcode.js
+++ b/lib/script/opcode.js
@@ -14,8 +14,7 @@ const common = require('./common');
 const BufferReader = require('../utils/reader');
 const StaticWriter = require('../utils/staticwriter');
 const opcodes = common.opcodes;
-
-const cache = [];
+const opCache = [];
 
 /**
  * A simple struct which contains
@@ -180,92 +179,6 @@ Opcode.prototype.getSize = function getSize() {
   }
 };
 
-/**
- * Inject properties from buffer reader.
- * @param {BufferReader} br
- * @private
- */
-
-Opcode.prototype.fromReader = function fromReader(br) {
-  const op = br.readU8();
-
-  if (op >= 0x01 && op <= 0x4b) {
-    if (br.left() < op) {
-      this.value = -1;
-      br.seek(br.left());
-      return this;
-    }
-    this.value = op;
-    this.data = br.readBytes(op);
-    return this;
-  }
-
-  let size;
-
-  switch (op) {
-    case opcodes.OP_PUSHDATA1:
-      if (br.left() < 1) {
-        this.value = -1;
-        break;
-      }
-      size = br.readU8();
-      if (br.left() < size) {
-        this.value = -1;
-        br.seek(br.left());
-        break;
-      }
-      this.value = op;
-      this.data = br.readBytes(size);
-      break;
-    case opcodes.OP_PUSHDATA2:
-      if (br.left() < 2) {
-        this.value = -1;
-        br.seek(br.left());
-        break;
-      }
-      size = br.readU16();
-      if (br.left() < size) {
-        this.value = -1;
-        br.seek(br.left());
-        break;
-      }
-      this.value = op;
-      this.data = br.readBytes(size);
-      break;
-    case opcodes.OP_PUSHDATA4:
-      if (br.left() < 4) {
-        this.value = -1;
-        br.seek(br.left());
-        break;
-      }
-      size = br.readU32();
-      if (br.left() < size) {
-        this.value = -1;
-        br.seek(br.left());
-        break;
-      }
-      this.value = op;
-      this.data = br.readBytes(size);
-      break;
-    default:
-      this.value = op;
-      break;
-  }
-
-  return this;
-};
-
-/**
- * Inject properties from serialized data.
- * @private
- * @param {Buffer} data
- * @returns {Opcode}
- */
-
-Opcode.prototype.fromRaw = function fromRaw(data) {
-  return this.fromReader(new BufferReader(data));
-};
-
 /**
  * Instantiate opcode from buffer reader.
  * @param {BufferReader} br
@@ -273,17 +186,79 @@ Opcode.prototype.fromRaw = function fromRaw(data) {
  */
 
 Opcode.fromReader = function fromReader(br) {
-  if (br.offset < br.data.length) {
-    const op = br.data[br.offset];
-    const cached = cache[op];
+  const value = br.readU8();
 
-    if (cached) {
-      br.offset++;
-      return cached;
+  const cached = opCache[value];
+
+  if (cached)
+    return cached;
+
+  const op = new Opcode(value, null);
+
+  if (value >= 0x01 && value <= 0x4b) {
+    if (br.left() < value) {
+      op.value = -1;
+      br.seek(br.left());
+      return op;
     }
+    op.value = value;
+    op.data = br.readBytes(value);
+    return op;
   }
 
-  return new Opcode(0, null).fromReader(br);
+  let size;
+
+  switch (value) {
+    case opcodes.OP_PUSHDATA1:
+      if (br.left() < 1) {
+        op.value = -1;
+        break;
+      }
+      size = br.readU8();
+      if (br.left() < size) {
+        op.value = -1;
+        br.seek(br.left());
+        break;
+      }
+      op.value = value;
+      op.data = br.readBytes(size);
+      break;
+    case opcodes.OP_PUSHDATA2:
+      if (br.left() < 2) {
+        op.value = -1;
+        br.seek(br.left());
+        break;
+      }
+      size = br.readU16();
+      if (br.left() < size) {
+        op.value = -1;
+        br.seek(br.left());
+        break;
+      }
+      op.value = value;
+      op.data = br.readBytes(size);
+      break;
+    case opcodes.OP_PUSHDATA4:
+      if (br.left() < 4) {
+        op.value = -1;
+        br.seek(br.left());
+        break;
+      }
+      size = br.readU32();
+      if (br.left() < size) {
+        op.value = -1;
+        br.seek(br.left());
+        break;
+      }
+      op.value = value;
+      op.data = br.readBytes(size);
+      break;
+    default:
+      op.value = value;
+      break;
+  }
+
+  return op;
 };
 
 /**
@@ -293,15 +268,7 @@ Opcode.fromReader = function fromReader(br) {
  */
 
 Opcode.fromRaw = function fromRaw(data) {
-  if (data.length > 0) {
-    const op = data[0];
-    const cached = cache[op];
-
-    if (cached)
-      return cached;
-  }
-
-  return new Opcode(0, null).fromRaw(data);
+  return Opcode.fromReader(new BufferReader(data));
 };
 
 /**
@@ -311,7 +278,7 @@ Opcode.fromRaw = function fromRaw(data) {
  */
 
 Opcode.fromOp = function fromOp(op) {
-  const cached = cache[op];
+  const cached = opCache[op];
 
   if (cached)
     return cached;
@@ -485,15 +452,15 @@ Opcode.isOpcode = function isOpcode(obj) {
 
 for (let value = 0x00; value <= 0xff; value++) {
   if (value >= 0x01 && value <= 0x4e) {
-    cache.push(null);
+    opCache.push(null);
     continue;
   }
 
-  const op = new Opcode(value);
+  const op = new Opcode(value, null);
 
   Object.freeze(op);
 
-  cache.push(op);
+  opCache.push(op);
 }
 
 /*