bn: make .strip() an internal method (see indutny#105)

(cherry picked from commit e88e7b7)

lib/bn.js

@@ -103,7 +103,7 @@
       this.negative = 1;
     }
 
-    this.strip();
+    this._strip();
 
     if (endian !== 'le') return;
 
@@ -180,7 +180,7 @@
         }
       }
     }
-    return this.strip();
+    return this._strip();
   };
 
   function parseHex (str, start, end) {
@@ -234,11 +234,12 @@
       this.words[j] |= (w << off) & 0x3ffffff;
       this.words[j + 1] |= w >>> (26 - off) & 0x3fffff;
     }
-    this.strip();
+    this._strip();
   };
 
   function parseBase (str, start, end, mul) {
     var r = 0;
+    var b = 0;
     var len = Math.min(str.length, end);
     for (var i = start; i < len; i++) {
       var c = str.charCodeAt(i) - 48;
@@ -247,16 +248,18 @@
 
       // 'a'
       if (c >= 49) {
-        r += c - 49 + 0xa;
+        b = c - 49 + 0xa;
 
       // 'A'
       } else if (c >= 17) {
-        r += c - 17 + 0xa;
+        b = c - 17 + 0xa;
 
       // '0' - '9'
       } else {
-        r += c;
+        b = c;
       }
+      assert(b < mul, 'Invalid character');
+      r += b;
     }
     return r;
   }
@@ -330,7 +333,7 @@
   };
 
   // Remove leading `0` from `this`
-  BN.prototype.strip = function strip () {
+  BN.prototype._strip = function strip () {
     while (this.length > 1 && this.words[this.length - 1] === 0) {
       this.length--;
     }
@@ -509,7 +512,7 @@
   };
 
   BN.prototype.toJSON = function toJSON () {
-    return this.toString(16);
+    return this.toString(16, 2);
   };
 
   BN.prototype.toBuffer = function toBuffer (endian, length) {
@@ -533,7 +536,7 @@
     assert(byteLength <= reqLength, 'byte array longer than desired length');
     assert(reqLength > 0, 'Requested array length <= 0');
 
-    this.strip();
+    this._strip();
     var littleEndian = endian === 'le';
     var res = allocate(ArrayType, reqLength);
 
@@ -708,7 +711,7 @@
       this.words[i] = this.words[i] | num.words[i];
     }
 
-    return this.strip();
+    return this._strip();
   };
 
   BN.prototype.ior = function ior (num) {
@@ -743,7 +746,7 @@
 
     this.length = b.length;
 
-    return this.strip();
+    return this._strip();
   };
 
   BN.prototype.iand = function iand (num) {
@@ -787,7 +790,7 @@
 
     this.length = a.length;
 
-    return this.strip();
+    return this._strip();
   };
 
   BN.prototype.ixor = function ixor (num) {
@@ -831,7 +834,7 @@
     }
 
     // And remove leading zeroes
-    return this.strip();
+    return this._strip();
   };
 
   BN.prototype.notn = function notn (width) {
@@ -853,7 +856,7 @@
       this.words[off] = this.words[off] & ~(1 << wbit);
     }
 
-    return this.strip();
+    return this._strip();
   };
 
   // Add `num` to `this` in-place
@@ -994,7 +997,7 @@
       this.negative = 1;
     }
 
-    return this.strip();
+    return this._strip();
   };
 
   // Subtract `num` from `this`
@@ -1040,7 +1043,7 @@
       out.length--;
     }
 
-    return out.strip();
+    return out._strip();
   }
 
   // TODO(indutny): it may be reasonable to omit it for users who don't need
@@ -1662,7 +1665,7 @@
       out.length--;
     }
 
-    return out.strip();
+    return out._strip();
   }
 
   function jumboMulTo (self, num, out) {
@@ -1879,7 +1882,7 @@
 
     out.negative = x.negative ^ y.negative;
     out.length = x.length + y.length;
-    return out.strip();
+    return out._strip();
   };
 
   // Multiply `this` by `num`
@@ -1997,7 +2000,7 @@
       this.length += s;
     }
 
-    return this.strip();
+    return this._strip();
   };
 
   BN.prototype.ishln = function ishln (bits) {
@@ -2065,7 +2068,7 @@
       this.length = 1;
     }
 
-    return this.strip();
+    return this._strip();
   };
 
   BN.prototype.ishrn = function ishrn (bits, hint, extended) {
@@ -2132,7 +2135,7 @@
       this.words[this.length - 1] &= mask;
     }
 
-    return this.strip();
+    return this._strip();
   };
 
   // Return only lowers bits of number
@@ -2207,7 +2210,7 @@
       }
     }
 
-    return this.strip();
+    return this._strip();
   };
 
   BN.prototype.addn = function addn (num) {
@@ -2249,7 +2252,7 @@
       this.words[i + shift] = w & 0x3ffffff;
     }
 
-    if (carry === 0) return this.strip();
+    if (carry === 0) return this._strip();
 
     // Subtraction overflow
     assert(carry === -1);
@@ -2261,7 +2264,7 @@
     }
     this.negative = 1;
 
-    return this.strip();
+    return this._strip();
   };
 
   BN.prototype._wordDiv = function _wordDiv (num, mode) {
@@ -2323,9 +2326,9 @@
       }
     }
     if (q) {
-      q.strip();
+      q._strip();
     }
-    a.strip();
+    a._strip();
 
     // Denormalize
     if (mode !== 'div' && shift !== 0) {
@@ -2494,7 +2497,7 @@
       carry = w % num;
     }
 
-    return this.strip();
+    return this._strip();
   };
 
   BN.prototype.divn = function divn (num) {
@@ -2746,7 +2749,7 @@
     if (this.negative !== 0 && !negative) return -1;
     if (this.negative === 0 && negative) return 1;
 
-    this.strip();
+    this._strip();
 
     var res;
     if (this.length > 1) {