Minor optimization to set buffer size appropriately

This avoids unnecessary allocations/reallocations while decoding a message by pre-sizing the buffer to the amount we know it will require. I feel like there's probably a better way to handle this, but this works for now.

messages/SLChallengeMessage.js

@@ -6,7 +6,11 @@ const MSG_ID = 14;
 
 exports.SLChallengeMessage = class SLChallengeMessage extends SLMessage {
   constructor(buf) {
-    super(0, MSG_ID);
+    var size;
+    if (buf) {
+      size = buf.readInt32LE(4) + 8;
+    }
+    super(0, MSG_ID, size);
 
     if (buf) {
       this._wroteSize = true;

messages/SLChemDataMessage.js

@@ -6,7 +6,12 @@ const MSG_ID = 12592;
 
 exports.SLChemDataMessage = class SLChemDataMessage extends SLMessage {
   constructor(buf) {
-    super(0, MSG_ID);
+    var size;
+    if (buf) {
+      size = buf.readInt32LE(4) + 8;
+    }
+    super(0, MSG_ID, size);
+
     if (!buf) {
       this.writeInt32LE(0); // controller index
     } else {

messages/SLControllerConfigMessage.js

@@ -6,7 +6,12 @@ const MSG_ID = 12532;
 
 exports.SLControllerConfigMessage = class SLControllerConfigMessage extends SLMessage {
   constructor(buf) {
-    super(0, MSG_ID);
+    var size;
+    if (buf) {
+      size = buf.readInt32LE(4) + 8;
+    }
+    super(0, MSG_ID, size);
+
     if (!buf) {
       this.writeInt32LE(0);
       this.writeInt32LE(0);

messages/SLGetGatewayDataMessage.js

@@ -6,7 +6,11 @@ const MSG_ID = 18003;
 
 exports.SLGetGatewayDataMessage = class SLGetGatewayDataMessage extends SLMessage {
   constructor(buf) {
-    super(0, MSG_ID);
+    var size;
+    if (buf) {
+      size = buf.readInt32LE(4) + 8;
+    }
+    super(0, MSG_ID, size);
 
     if (typeof buf === 'string') {
       this.writeSLString(buf);

messages/SLMessage.js

@@ -3,8 +3,14 @@
 const SmartBuffer = require('smart-buffer').SmartBuffer;
 
 exports.SLMessage = class SLMessage extends SmartBuffer {
-  constructor(senderId, messageId) {
+  constructor(senderId, messageId, size) {
-    super();
+    var options;
+    if (size) {
+      options = {
+        size: size,
+      };
+    }
+    super(options);
 
     if (typeof senderId === 'number' || typeof senderId === 'undefined') {
       this.writeUInt16LE(senderId || 0);

messages/SLPoolStatusMessage.js

@@ -9,7 +9,12 @@ const POOL_CIRCUIT_ID = 505;
 
 exports.SLPoolStatusMessage = class SLPoolStatusMessage extends SLMessage {
   constructor(buf) {
-    super(0, MSG_ID);
+    var size;
+    if (buf) {
+      size = buf.readInt32LE(4) + 8;
+    }
+    super(0, MSG_ID, size);
+
     if (!buf) {
       this.writeInt32LE(0);
     } else {

messages/SLSaltCellConfigMessage.js

@@ -6,7 +6,12 @@ const MSG_ID = 12572;
 
 exports.SLSaltCellConfigMessage = class SLSaltCellConfigMessage extends SLMessage {
   constructor(buf) {
-    super(0, MSG_ID);
+    var size;
+    if (buf) {
+      size = buf.readInt32LE(4) + 8;
+    }
+    super(0, MSG_ID, size);
+
     if (!buf) {
       this.writeInt32LE(0); // controller index
     } else {

messages/SLVersionMessage.js

@@ -6,7 +6,12 @@ const MSG_ID = 8120;
 
 exports.SLVersionMessage = class SLVersionMessage extends SLMessage {
   constructor(buf) {
-    super(0, MSG_ID);
+    var size;
+    if (buf) {
+      size = buf.readInt32LE(4) + 8;
+    }
+    super(0, MSG_ID, size);
+
     if (buf) {
       this._wroteSize = true;
       this.writeBuffer(buf, 0);