axelson
diff --git a/‎bits.js
Lines changed: 95 additions & 0 deletions b/‎bits.js
Lines changed: 95 additions & 0 deletions
@@ -0,0 +1,95 @@
+/*jslint eqeqeq: true, immed: true, newcap: true, nomen: true, onevar: true, plusplus: true, regexp: true, undef: true, white: true, indent: 2 */
+
+// Converter between javascript values and "raw"
+// streams which are really arrays of 8 bit integers.
+// the add functions return this so they can be chained.
+// Note that this works directly on the array object.
+
+// Encode number as 32 bit 2s compliment
+Array.prototype.add_int32 = function (number) {
+  var unsigned = (number < 0) ? (number + 0x100000000) : number;
+  this.push(Math.floor(unsigned / 0xffffff));
+  unsigned &= 0xffffff;
+  this.push(Math.floor(unsigned / 0xffff));
+  unsigned &= 0xffff;
+  this.push(Math.floor(unsigned / 0xff));
+  unsigned &= 0xff;
+  this.push(Math.floor(unsigned));
+  return this;
+};
+
+// Encode number as 16 bit 2s compliment
+Array.prototype.add_int16 = function (number) {
+  var unsigned = (number < 0) ? (number + 0x10000) : number;
+  this.push(Math.floor(unsigned / 0xff));
+  unsigned &= 0xff;
+  this.push(Math.floor(unsigned));
+  return this;
+};
+
+// Encode string without null terminator
+Array.prototype.add_raw_string = function (text) {
+  for (var i = 0, l = text.length; i < l; i += 1) {
+    this.push(text.charCodeAt(i));
+  }
+  return this;
+};
+
+// Encode text as null terminated string
+Array.prototype.add_cstring = function (text) {
+  this.add_raw_string(text).push(0);
+  return this;
+};
+
+// Encode as a null terminated array of cstrings
+Array.prototype.add_multi_cstring = function (fields) {
+  for (var i = 0, l = fields.length; i < l; i += 1) {
+    this.add_cstring(fields[i]);
+  }
+  this.push(0);
+  return this;
+};
+
+// Convert 4 bytes to signed 32 bit integer
+Array.prototype.parse_int32 = function () {
+  var unsigned = this.shift() * 0x1000000 + this.shift() * 0x10000 + this.shift() * 0x100 + this.shift();
+  return (unsigned & 0x80000000) ? (unsigned - 0x100000000) : unsigned;
+};
+
+// Convert 2 bytes to signed 16 bit integer
+Array.prototype.parse_int16 = function () {
+  var unsigned = this.shift() * 0x100 + this.shift();
+  return (unsigned & 0x8000) ? (unsigned - 0x10000) : unsigned;
+};
+
+// Grab number of bytes as a string
+Array.prototype.parse_raw_string = function (len) {
+  var text = "";
+  while (len > 0) {
+    len -= 1;
+    text += String.fromCharCode(this.shift());
+  }
+  return text;
+};
+
+// Grab a null terminated string from the this
+Array.prototype.parse_cstring = function () {
+  var text = "";
+  while (this.length > 0 && this[0] !== 0) {
+    text += String.fromCharCode(this.shift());
+  }
+  this.shift();
+  return text;
+};
+
+// Grab a null terminated array of null terminated strings
+Array.prototype.parse_multi_cstring = function () {
+  var fields = [];
+  while (this[0] !== 0) {
+    fields.push(this.parse_cstring());
+  }
+  this.pop();
+  return fields;
+};
+
+