Little Endian support

index.js

@@ -12,8 +12,11 @@ var Reader = module.exports = function(options) {
   this.chunkLength = 0
   this.headerSize = options.headerSize || 0
   this.lengthPadding = options.lengthPadding || 0
+  this.lengthLE = options.lengthLE || false
+  this.lengthSize = options.lengthSize || 4
+  assert( this.lengthSize <= 6, 'lengths of more than 6 bytes are not currently supported' )
   this.header = null
-  assert(this.headerSize < 2, 'pre-length header of more than 1 byte length not currently supported')
+  assert(this.headerSize <= 6 , 'pre-length header with more than a 6 byte length not currently supported')
 }
 
 Reader.prototype.addChunk = function(chunk) {
@@ -41,24 +44,29 @@ Reader.prototype.addChunk = function(chunk) {
 }
 
 Reader.prototype.read = function() {
-  if(this.chunkLength < (this.headerSize + 4 + this.offset)) {
+  if(this.chunkLength < (this.headerSize + this.lengthSize + this.offset)) {
     return false
   }
 
   if(this.headerSize) {
-    this.header = this.chunk[this.offset]
+    if ( this.lengthLE )
+      this.header = this.chunk.readUIntLE( this.offset, this.headerSize );
+    else this.header = this.chunk.readUIntBE( this.offset, this.headerSize );
   }
 
   //read length of next item
-  var length = this.chunk.readUInt32BE(this.offset + this.headerSize) + this.lengthPadding
+  var length = this.lengthPadding;
+  if ( this.lengthLE )
+    length += this.chunk.readUIntLE( this.offset + this.headerSize, this.lengthSize );
+  else length += this.chunk.readUIntBE( this.offset + this.headerSize, this.lengthSize );
 
   //next item spans more chunks than we have
-  var remaining = this.chunkLength - (this.offset + 4 + this.headerSize)
+  var remaining = this.chunkLength - (this.offset + this.lengthSize + this.headerSize)
   if(length > remaining) {
     return false
   }
 
-  this.offset += (this.headerSize + 4)
+  this.offset += (this.headerSize + this.lengthSize)
   var result = this.chunk.slice(this.offset, this.offset + length)
   this.offset += length
   return result

test/index.js

@@ -146,3 +146,25 @@ describe('postgres style packet', function() {
     assert.equal(result[3], 0)
   })
 })
+
+
+describe('little-endian style packet', function() {
+  beforeEach(function() {
+    this.reader = new Reader({
+      headerSize: 4,
+      lengthLE: true,
+      lengthPadding: 8,
+    })
+  })
+
+  it('reads 4-byte LE size with a 4 byte LE header and 8 byte padding', function() {
+    var buf = Buffer.from([0x7A, 0xB1, 0xEA, 0x06, 4, 0, 0, 0, 7, 0, 0, 0, 0, 0, 0, 0, 0x00, 0xA4, 0xD3, 0xF1]);
+    this.reader.addChunk( buf )
+    var result = this.reader.read()
+    assert(result)
+    assert.equal(this.reader.header, 0x06EAB17A)
+    assert.equal(result.length, 12)
+    for ( i = 0; i < result.length; ++i )
+      assert.equal(result[i], buf[i+8])
+  })
+})