node-int64 - npm Package Compare versions

Comparing version 0.1.0 to 0.2.0

Int64.js

 /**
 * Support for handling 64-bit int numbers in Javascript (node.js)
 *
-* JS Numbers are IEEE-754 double-precision floats, which limits the range of
-* integer values that can be accurately represented to +/- 2^^53.
+* JS Numbers are IEEE-754 binary double-precision floats, which limits the
+* range of values that can be represented with integer precision to:
 *
+* 2^^53 <= N <= 2^53
+*
 * Int64 objects wrap a node Buffer that holds the 8-bytes of int64 data.  These
-* objects operate directly on the buffer, which means that if they are created
-* using an existing buffer, setting the value will modify the Buffer and
+* objects operate directly on the buffer which means that if they are created
+* using an existing buffer then setting the value will modify the Buffer, and
 * vice-versa.
+*
+* For details about IEEE-754 see:
+* http://en.wikipedia.org/wiki/Double_precision_floating-point_format
 */
@@ -18,4 +23,6 @@
 // Map for converting hex octets to strings
-var _HEX = [];
-for (var i = 0; i < 256; i++) _HEX[i] = (i > 0xF ? '' : '0') + i.toString(16);
+var _HEX = [], _PADHEX = [];
+for (var i = 0; i < 256; i++) {
+  _HEX[i] = (i > 0xF ? '' : '0') + i.toString(16);
+}
 
@@ -68,5 +75,5 @@ //
   * Set the value:
-  * new Int64(string) - A hexidecimal string
-  * new Int64(number) - Number (throws if n is outside int64 range)
-  * new Int64(hi, lo) - Raw bits as two 32-bit values
+  * setValue(string) - A hexidecimal string
+  * setValue(number) - Number (throws if n is outside int64 range)
+  * setValue(hi, lo) - Raw bits as two 32-bit values
   */
@@ -96,7 +103,7 @@ setValue: function(hi, lo) {
 
-    // TODO: Do we want to throw if hi/lo is outside int32 range here?
+    // Technically we should throw if hi/lo is outside int32 range here, but
+    // it's not worth the effort.
 
     // Copy bytes to buffer
-    b = this.buffer;
-    var o = this.offset;
+    var b = this.buffer, o = this.offset;
     for (var i = 7; i >= 0; i--) {
@@ -112,47 +119,53 @@ b[o+i] = lo & 0xff;
   /**
-  * Return the approximate error involved in converting the current value to a
-  * native JS number.  If > 0, the value is outside the range JS can represent
-  * to integer precision.
+  * Convert to a JS Number. Returns +/-Infinity for values that can't be
+  * represented to integer precision.
   */
-  error: function() {
-    return Math.ceil(Math.abs(this.valueOf()) / Int64.MAX_INT) - 1;
+  valueOf: function() {
+    var b = this.buffer, o = this.offset;
+
+    var negate = b[0] & 0x80, x = 0, carry = 1;
+    for (var i = 0, ii = o + 7; i < 8; i++, ii--) {
+      var v = b[ii];
+      // Do a running 2's complement for negative numbers
+      if (negate) {
+        v = (v ^ 0xff) + carry;
+        carry = v >> 8;
+      }
+
+      x += (v & 0xff) * Math.pow(256, i);
+    }
+
+    // Return Infinity if we've lost integer precision
+    if (x >= Int64.MAX_INT) {
+      return negate ? -Infinity : Infinity;
+    }
+
+    return negate ? -x : x;
   },
 
   /**
-  * Convert to a JS Number.
-  *
-  * Be aware that if the returned value is outside the range ...
-  *
-  *     Int64.MIN_INT <= x <= Int64.MAX_INT
-  *
-  * ... it is unlikely to exactly represent the underlying 64-bit value.
+  * Return string value
   */
-  valueOf: function() {
+  toString: function(radix) {
+    return this.valueOf().toString(radix || 10);
+  },
+
+  /**
+  * Return a string showing the buffer octets, with MSB on the left.
+  */
+  toOctetString: function(sep) {
+    var out = new Array(8);
     var b = this.buffer, o = this.offset;
-    var negate = b[0] & 0x80, x = 0, xx = 1;
-    if (negate) this._2scomp();
-    for (var i = o + 7; i >= o; i--) {
-      var v = b[i] & (i == 0 ? 0x7f : 0xff);
-      x += v*xx;
-      xx *= 0x100;
+    for (var i = 0; i < 8; i++) {
+      out[i] = _HEX[b[o+i]];
     }
-    if (negate) {
-      x = -x;
-      this._2scomp();
-    }
-    return x;
+    return out.join(sep || '');
   },
 
   /**
-  * Get value as a string of hex octets
-  *
-  * @param sep (String) string to join() with. Default=''
+  * Pretty output in console.log
   */
-  toString: function(sep) {
-    var b = this.buffer, o = this.offset, s = ['0x'];
-    for (var i = 0; i < 8; i++) {
-      s.push(_HEX[this.buffer[o+i]]);
-    }
-    return s.join('');
+  inspect: function() {
+    return '[Int64 value:' + this + ' octets:' + this.toOctetString(' ') + ']';
   }
 };

package.json

@@ -5,3 +5,3 @@ {
   "url"           : "http://github.com/broofa/node-int64",
-  "keywords"      : ["math", "integer"],
+  "keywords"      : ["math", "integer", "int64"],
   "author"        : "Robert Kieffer <[e-mail]>",
@@ -12,3 +12,3 @@ "contributors"  : [],
   "main"          : "./Int64.js",
-  "version"       : "0.1.0"
+  "version"       : "0.2.0"
 }

test.js

 var Int64 = require('./Int64');
 
 var args = [
-  [0],
-  [1],
-  [-1],
-  [1e18],
-  ['0ff1234500654321'],
-  [0xff12345, 0x654321],
-  ['0x0001234500654321'],
-  ['0xFFFFFFFFFFFFFFFF']
+  [0],                     '0000000000000000',
+  [1],                     '0000000000000001',
+  [-1],                    'ffffffffffffffff',
+  [1e18],                  '0de0b6b3a7640000',
+  ['0ff1234500654321'],    '0ff1234500654321',
+  [0xff12345, 0x654321],   '0ff1234500654321',
+  ['0x0000123450654321'],  '0000123450654321',
+  ['0xFFFFFFFFFFFFFFFF'],  'ffffffffffffffff'
 ];
 
-for (var i = 0; i < args.length; i++) {
-  var a = args[i];
+for (var i = 0; i < args.length; i += 2) {
+  var a = args[i], octets = args[i+1];
   // Create instance
@@ -20,6 +20,8 @@ var x = new Int64();
 
-  console.log('  args: ' + a);
-  console.log('value: ' + x + ', string: ' + x.toString() + ', err: ' + x.error());
+  console.log('new Int64(' + a + ')');
+  var pass = x.toOctetString() == octets;
+  console.log((pass ? 'PASS' : 'FAIL') + ' - value:' + x +
+              ', octets: ' + x.toOctetString());
 
   console.log('-----------');
 }

Fixed alerts

No README

Quality

Package does not have a README. This may indicate a failed publish or a low quality package.

Found 1 instance in 1 package

Improved metrics

Total package byte prevSize

8373

increased by61.61%

Number of package files

4

increased by33.33%

Lines of code

169

increased by6.29%

Number of medium quality alerts

0

decreased by-100%

Number of lines in readme file

70

increased byInfinity%

No dependency changes