Add fix for big-endian platforms (Closes: #85)

Author: guimard

lib/to-buffer.js

@@ -1,12 +1,64 @@
 var Buffer = require('safe-buffer').Buffer
 
+function swapBytes(buf, size) {
+  var bytes = new Uint8Array(buf.slice());
+  var len = bytes.length;
+  var holder;
+
+  if (size == 2) {
+    //16 bit
+    for (var i = 0; i<len; i+=2) {
+        holder = bytes[i];
+        bytes[i] = bytes[i+1];
+        bytes[i+1] = holder;
+    }
+  } else if (size == 4) {
+    //32 bit
+    for (var i = 0; i<len; i+=4) {
+      holder = bytes[i];
+      bytes[i] = bytes[i+3];
+      bytes[i+3] = holder;
+      holder = bytes[i+1];
+      bytes[i+1] = bytes[i+2];
+      bytes[i+2] = holder;
+    }
+  } else if (size == 8) {
+    //32 bit
+    for (var i = 0; i<len; i+=8) {
+      holder = bytes[i];
+      bytes[i] = bytes[i+7];
+      bytes[i+7] = holder;
+      holder = bytes[i+1];
+      bytes[i+1] = bytes[i+6];
+      bytes[i+6] = holder;
+      holder = bytes[i+2];
+      bytes[i+2] = bytes[i+5];
+      bytes[i+5] = holder;
+      holder = bytes[i+3];
+      bytes[i+3] = bytes[i+4];
+      bytes[i+4] = holder;
+    }
+  }
+  return Buffer.from(bytes);
+}
+
+function checkEndian() {
+  var arrayBuffer = new ArrayBuffer(2);
+  var uint8Array = new Uint8Array(arrayBuffer);
+  var uint16array = new Uint16Array(arrayBuffer);
+  uint8Array[0] = 0xAA; //set first byte
+  uint8Array[1] = 0xBB; //set second byte
+  if(uint16array[0] === 0xBBAA) return false;
+  if(uint16array[0] === 0xAABB) return true;
+}
+
 module.exports = function (thing, encoding, name) {
   if (Buffer.isBuffer(thing)) {
     return thing
   } else if (typeof thing === 'string') {
     return Buffer.from(thing, encoding)
   } else if (ArrayBuffer.isView(thing)) {
-    return Buffer.from(thing.buffer)
+    return checkEndian() ? swapBytes(thing.buffer,thing.BYTES_PER_ELEMENT) : Buffer.from(thing.buffer);
   } else {
     throw new TypeError(name + ' must be a string, a Buffer, a typed array or a DataView')
   }