Merge branch 'modularize-bignum'

clayzermk1 · Aug 26, 2016 · e5408c6 · e5408c6
2 parents b5c791f + 3e99f00
commit e5408c6
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Showing 6 changed files with 128 additions and 77 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,3 +1,6 @@
+# 0.2.1
+* Modularized bignum.
+
 # 0.2.0
 * Added bignum parsing (#4).
 * Switched testing frameworks from `tap` to `tape`.

diff --git a/lib/bignum.js b/lib/bignum.js
@@ -0,0 +1,99 @@
+var debug = require('debug')('lib:bignum');
+
+// Copied directly from https://github.com/MikeMcl/decimal.js/blob/fb37ca6bde56676d6d5a98df2bf8721e8fa81085/decimal.js#L27
+// Base conversion alphabet.
+var NUMERALS = '0123456789abcdef';
+
+module.exports = (function () {
+  function Bignum(rawString, encoding) {
+    this.buffer = new Buffer(rawString);
+    this.encoding = encoding;
+    return this;
+  }
+
+  Bignum.prototype._getWordLength = function () {
+    // the word length appears to always be positive but still follows the Marshal length logic
+    var wordLength = this.buffer.readInt8(1); // read the number of "machine words" - 16bit integers
+    if (wordLength === 0) {
+      wordLength = 0;
+    }
+    else if (wordLength >= 6) {
+      wordLength = wordLength - 5;
+    }
+    else if (wordLength <= -6) {
+      wordLength = wordLength + 5;
+    }
+
+    debug('wordLength: %s', wordLength);
+
+    return wordLength;
+  }
+
+  Bignum.prototype._readByteString = function () {
+    // it appears that words are always zero padded - no odd number of bytes
+    var byteLength = this._getWordLength() * 2;
+    var byteString = '';
+    var i, index;
+    for (i = 0, index = 2; i < byteLength; i++, index++) {
+      byteString = this.buffer.toString('hex', index, index + 1) + byteString;
+    }
+
+    debug('byteString: %s', byteString);
+
+    return byteString;
+  }
+
+  Bignum.prototype._readBase10String = function () {
+    var byteString = this._readByteString();
+
+    // Modified from https://github.com/MikeMcl/decimal.js/blob/fb37ca6bde56676d6d5a98df2bf8721e8fa81085/decimal.js#L2597
+    var base10Array = [0];
+    var j, base10ArrayLength;
+    for (i = 0; i < byteString.length; i++) {
+      for (base10ArrayLength = base10Array.length; base10ArrayLength--;) {
+        base10Array[base10ArrayLength] *= 16;
+      }
+      base10Array[0] += NUMERALS.indexOf(byteString.charAt(i));
+      for (j = 0; j < base10Array.length; j++) {
+        if (base10Array[j] > 10 - 1) {
+          if (base10Array[j + 1] === void 0) {
+            base10Array[j + 1] = 0;
+          }
+          base10Array[j + 1] += base10Array[j] / 10 | 0;
+          base10Array[j] %= 10;
+        }
+      }
+    }
+
+    // trim leading zeros
+    while (base10Array[base10Array.length] === 0) {
+      base10Array.pop();
+    }
+
+    var base10String = base10Array.reverse().join('');
+    debug('base10String: %s', base10String);
+
+    return base10String;
+  }
+
+  Bignum.prototype.isNegative = function () {
+    return (this.buffer.readInt8(0) === 0x2d); // read the sign byte and check for '-'
+  }
+
+  Bignum.prototype.toString = function () {
+    var bignum = this._readBase10String();
+
+    if (this.isNegative()) {
+      bignum = '-' + bignum;
+    }
+    debug('bignum: %s', bignum);
+
+    return bignum;
+  };
+
+  Bignum.prototype.toJSON = function () {
+    return this.toString();
+  };
+
+  return Bignum;
+})();
diff --git a/lib/ivar.js b/lib/ivar.js
@@ -7,7 +7,7 @@ Ivar = (function () {
     this.string = this.buffer.toString('utf8');
 
     return this;
-  };
+  }
 
   Ivar.prototype.toString = function () {
     return this.buffer.toString(this.encoding || 'utf8');

diff --git a/lib/marshal.js b/lib/marshal.js
@@ -1,19 +1,19 @@
 var debug = require('debug')('marshal');
-var MarshalError = require('./marshalError');
-var Ivar = require('./ivar');
 
-// Copied directly from https://github.com/MikeMcl/decimal.js/blob/fb37ca6bde56676d6d5a98df2bf8721e8fa81085/decimal.js#L27
-// Base conversion alphabet.
-var NUMERALS = '0123456789abcdef';
+var Bignum = require('./bignum.js');
+var Ivar = require('./ivar.js');
+var MarshalError = require('./marshalError.js');
 
 var Marshal;
 
 Marshal = (function () {
   function Marshal (buffer, encoding) {
-    if (buffer !== void 0) this.load(buffer, encoding);
+    if (buffer !== void 0) {
+      this.load(buffer, encoding);
+    }
 
     return this;
-  };
+  }
 
   Marshal.prototype._parse = function () {
     var typeCode = this.buffer.readUInt8(this._index++);
@@ -45,9 +45,9 @@ Marshal = (function () {
         return this._parseHash();
       case 0x6C: // l - bignum
         return this._parseBignum();
-      case 0x2F: // / - regexp
-      case 0x63: // c - class
-      case 0x6D: // m - module
+      // case 0x2F: // / - regexp
+      // case 0x63: // c - class
+      // case 0x6D: // m - module
       default:
         throw new MarshalError('unsupported typecode ' + typeCode, this);
     }
@@ -57,69 +57,18 @@ Marshal = (function () {
    * @return The decoded bignum.
    */
   Marshal.prototype._parseBignum = function () {
-    var isNegative = (this.buffer.readInt8(this._index++) === 0x2d); // read the sign byte and check for '-'
-    debug('isNegative: %s', isNegative);
-
-    // the word length appears to always be positive but still follows the Marshal length logic
-    var wordLength = this.buffer.readInt8(this._index++); // read the number of "machine words" - 16bit integers
-    if (wordLength === 0) {
-      wordLength = 0;
-    }
-    else if (wordLength >= 6) {
-      wordLength = wordLength - 5;
-    }
-    else if (wordLength <= -6) {
-      wordLength = wordLength + 5;
-    }
-    debug('wordLength: %s', wordLength);
-
-    // it appears that words are always zero padded - no odd number of bytes
-    var byteLength = wordLength * 2;
-    var byteString = '';
-    for (var i = 0; i < byteLength; i++, this._index++) {
-      byteString = this.buffer.toString('hex', this._index, this._index + 1) + byteString;
-    }
-    debug('byteString: %j', byteString);
-
-    // Modified from https://github.com/MikeMcl/decimal.js/blob/fb37ca6bde56676d6d5a98df2bf8721e8fa81085/decimal.js#L2597
-    var base10Array = [0];
-    var i, j, base10ArrayLength;
-    for (i = 0; i < byteString.length; i++) {
-      for (base10ArrayLength = base10Array.length; base10ArrayLength--;) base10Array[base10ArrayLength] *= 16;
-      base10Array[0] += NUMERALS.indexOf(byteString.charAt(i));
-      for (j = 0; j < base10Array.length; j++) {
-        if (base10Array[j] > 10 - 1) {
-          if (base10Array[j + 1] === void 0) base10Array[j + 1] = 0;
-          base10Array[j + 1] += base10Array[j] / 10 | 0;
-          base10Array[j] %= 10;
-        }
-      }
-    }
-
-    // trim leading zeros
-    while (base10Array[base10Array.length] === 0) {
-      base10Array.pop();
-    }
-
-    base10Array.reverse();
-    debug('base10Array: %j', base10Array);
+    var bignum = new Bignum(this.buffer.slice(this._index), 'hex');
 
-    var bignum = base10Array.join('');
-
-    if (isNegative) {
-      bignum = '-' + bignum;
-    }
-    debug('bignum: %s', bignum);
-
-    return bignum;
-  }
+    return bignum.toString();
+  };
 
   /** Parse an integer.
    * Used for reading of integer types and array lengths.
    * @return The decoded integer.
    */
   Marshal.prototype._parseInteger = function () {
     var small = this.buffer.readInt8(this._index++); // read a signed byte
+    var large;
     if (small === 0) {
       return 0;
     }
@@ -130,42 +79,42 @@ Marshal = (function () {
       return small + 5;
     }
     else if (small === 1) {
-      var large = this.buffer.readUInt8(this._index);
+      large = this.buffer.readUInt8(this._index);
       this._index += 1;
       return large;
     }
     else if (small === 2) {
-      var large = this.buffer.readUInt16LE(this._index);
+      large = this.buffer.readUInt16LE(this._index);
       this._index += 2;
       return large;
     }
     else if (small === 3) {
-      var large = new Buffer(this.buffer.toString('hex', this._index, this._index + 3) + '00', 'hex').readUInt32LE(0);
+      large = new Buffer(this.buffer.toString('hex', this._index, this._index + 3) + '00', 'hex').readUInt32LE(0);
       this._index += 3;
       return large;
     }
     else if (small === 4) {
-      var large = this.buffer.readUInt32LE(this._index);
+      large = this.buffer.readUInt32LE(this._index);
       this._index += 4;
       return large;
     }
     else if (small === -1) {
-      var large = -(~(0xffffff00 + this.buffer.readUInt8(this._index)) + 1);
+      large = -(~(0xffffff00 + this.buffer.readUInt8(this._index)) + 1);
       this._index += 1;
       return large;
     }
     else if (small === -2) {
-      var large = this.buffer.readInt16LE(this._index);
+      large = this.buffer.readInt16LE(this._index);
       this._index += 2;
       return large;
     }
     else if (small === -3) {
-      var large = -(~(((0xffff0000 + this.buffer.readUInt16LE(this._index + 1)) << 8) + this.buffer.readUInt8(this._index)) + 1);
+      large = -(~(((0xffff0000 + this.buffer.readUInt16LE(this._index + 1)) << 8) + this.buffer.readUInt8(this._index)) + 1);
       this._index += 3;
       return large;
     }
     else if (small === -4) {
-      var large = this.buffer.readInt32LE(this._index);
+      large = this.buffer.readInt32LE(this._index);
       this._index += 4;
       return large;
     }
@@ -205,7 +154,7 @@ Marshal = (function () {
     var object = this._parseHash();
 
     // attach name
-    object['_name'] = name;
+    object._name = name;
 
     return object;
   };

diff --git a/lib/marshalError.js b/lib/marshalError.js
@@ -19,7 +19,7 @@ MarshalError = (function () {
         instance.buffer.toString('utf8', instance._index - 1, instance._index) + ' ' +
         instance.buffer.toString('utf8', instance._index));
     Error.captureStackTrace(this, this.constructor);
-  };
+  }
 
   util.inherits(MarshalError, Error);
 

diff --git a/package.json b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "marshal",
-  "version": "0.2.0",
+  "version": "0.2.1",
   "description": "Parse Ruby's Marshal strings into JavaScript objects/JSON.",
   "main": "index.js",
   "scripts": {