diff --git a/README.md b/README.md
index 7e1961d4..b5e35ff0 100644
--- a/README.md
+++ b/README.md
@@ -16,12 +16,12 @@ As a command-line utility:
 
     $ semver -h
 
-    Usage: semver <version> [<version> [...]] [-r <range> | -i <inc> | -d <dec>]
+    Usage: semver <version> [<version> [...]] [-r <range> | -i <inc> | --preid <identifier> | -l | -rv]
     Test if version(s) satisfy the supplied range(s), and sort them.
 
     Multiple versions or ranges may be supplied, unless increment
-    or decrement options are specified.  In that case, only a single
-    version may be used, and it is incremented by the specified level
+    option is specified.  In that case, only a single version may
+    be used, and it is incremented by the specified level
 
     Program exits successfully if any valid version satisfies
     all supplied ranges, and prints all satisfying versions.
@@ -101,6 +101,30 @@ the user is indicating that they are aware of the risk.  However, it
 is still not appropriate to assume that they have opted into taking a
 similar risk on the *next* set of prerelease versions.
 
+#### Prerelease Identifiers
+
+The method `.inc` takes an additional `identifier` string argument that
+will append the value of the string as a prerelease identifier:
+
+```javascript
+> semver.inc('1.2.3', 'pre', 'beta')
+'1.2.4-beta.0'
+```
+
+command-line example:
+
+```shell
+$ semver 1.2.3 -i prerelease --preid beta
+1.2.4-beta.0
+```
+
+Which then can be used to increment further:
+
+```shell
+$ semver 1.2.4-beta.0 -i prerelease
+1.2.4-beta.1
+```
+
 ### Advanced Range Syntax
 
 Advanced range syntax desugars to primitive comparators in
@@ -161,8 +185,6 @@ comparator.  Allows minor-level changes if not.
   `1.2.4-beta.2` would not, because it is a prerelease of a
   different `[major, minor, patch]` tuple.
 
-Note: this is the same as the `~>` operator in rubygems.
-
 #### Caret Ranges `^1.2.3` `^0.2.5` `^0.0.4`
 
 Allows changes that do not modify the left-most non-zero digit in the
@@ -226,6 +248,9 @@ strings that they parse.
     same as `prepatch`. It increments the patch version, then makes a
     prerelease. If the input version is already a prerelease it simply
     increments it.
+* `major(v)`: Return the major version number.
+* `minor(v)`: Return the minor version number.
+* `patch(v)`: Return the patch version number.
 
 ### Comparison
 
@@ -245,6 +270,9 @@ strings that they parse.
   `v2` is greater.  Sorts in ascending order if passed to `Array.sort()`.
 * `rcompare(v1, v2)`: The reverse of compare.  Sorts an array of versions
   in descending order when passed to `Array.sort()`.
+* `diff(v1, v2)`: Returns difference between two versions by the release type
+  (`major`, `premajor`, `minor`, `preminor`, `patch`, `prepatch`, or `prerelease`),
+  or null if the versions are the same.
 
 
 ### Ranges
diff --git a/bin/semver b/bin/semver
index 41c148fb..c5f2e857 100755
--- a/bin/semver
+++ b/bin/semver
@@ -12,6 +12,7 @@ var argv = process.argv.slice(2)
   , inc = null
   , version = require("../package.json").version
   , loose = false
+  , identifier = undefined
   , semver = require("../semver")
   , reverse = false
 
@@ -47,6 +48,9 @@ function main () {
             break
         }
         break
+      case "--preid":
+        identifier = argv.shift()
+        break
       case "-r": case "--range":
         range.push(argv.shift())
         break
@@ -88,7 +92,7 @@ function success () {
   }).map(function (v) {
     return semver.clean(v, loose)
   }).map(function (v) {
-    return inc ? semver.inc(v, inc, loose) : v
+    return inc ? semver.inc(v, inc, loose, identifier) : v
   }).forEach(function (v,i,_) { console.log(v) })
 }
 
@@ -111,6 +115,10 @@ function help () {
               ,"        prepatch, or prerelease.  Default level is 'patch'."
               ,"        Only one version may be specified."
               ,""
+              ,"--preid <identifier>"
+              ,"        Identifier to be used to prefix premajor, preminor,"
+              ,"        prepatch or prerelease version increments."
+              ,""
               ,"-l --loose"
               ,"        Interpret versions and ranges loosely"
               ,""
diff --git a/package.json b/package.json
index 9a1ca584..549b233f 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "semver",
-  "version": "4.0.3",
+  "version": "4.3.2",
   "description": "The semantic version parser used by npm.",
   "main": "semver.js",
   "browser": "semver.browser.js",
@@ -14,7 +14,7 @@
     "uglify-js": "~2.3.6"
   },
   "license": "BSD",
-  "repository": "git://github.com/isaacs/node-semver.git",
+  "repository": "git://github.com/npm/node-semver.git",
   "bin": {
     "semver": "./bin/semver"
   }
diff --git a/semver.js b/semver.js
index b0da846a..d265b568 100644
--- a/semver.js
+++ b/semver.js
@@ -20,6 +20,9 @@ if (typeof module === 'object' && module.exports === exports)
 // Not necessarily the package version of this code.
 exports.SEMVER_SPEC_VERSION = '2.0.0';
 
+var MAX_LENGTH = 256;
+var MAX_SAFE_INTEGER = Number.MAX_SAFE_INTEGER || 9007199254740991;
+
 // The actual regexps go on exports.re
 var re = exports.re = [];
 var src = exports.src = [];
@@ -233,8 +236,18 @@ for (var i = 0; i < R; i++) {
 
 exports.parse = parse;
 function parse(version, loose) {
+  if (version.length > MAX_LENGTH)
+    return null;
+
   var r = loose ? re[LOOSE] : re[FULL];
-  return (r.test(version)) ? new SemVer(version, loose) : null;
+  if (!r.test(version))
+    return null;
+
+  try {
+    return new SemVer(version, loose);
+  } catch (er) {
+    return null;
+  }
 }
 
 exports.valid = valid;
@@ -262,6 +275,9 @@ function SemVer(version, loose) {
     throw new TypeError('Invalid Version: ' + version);
   }
 
+  if (version.length > MAX_LENGTH)
+    throw new TypeError('version is longer than ' + MAX_LENGTH + ' characters')
+
   if (!(this instanceof SemVer))
     return new SemVer(version, loose);
 
@@ -279,6 +295,15 @@ function SemVer(version, loose) {
   this.minor = +m[2];
   this.patch = +m[3];
 
+  if (this.major > MAX_SAFE_INTEGER || this.major < 0)
+    throw new TypeError('Invalid major version')
+
+  if (this.minor > MAX_SAFE_INTEGER || this.minor < 0)
+    throw new TypeError('Invalid minor version')
+
+  if (this.patch > MAX_SAFE_INTEGER || this.patch < 0)
+    throw new TypeError('Invalid patch version')
+
   // numberify any prerelease numeric ids
   if (!m[4])
     this.prerelease = [];
@@ -355,35 +380,35 @@ SemVer.prototype.comparePre = function(other) {
 
 // preminor will bump the version up to the next minor release, and immediately
 // down to pre-release. premajor and prepatch work the same way.
-SemVer.prototype.inc = function(release) {
+SemVer.prototype.inc = function(release, identifier) {
   switch (release) {
     case 'premajor':
       this.prerelease.length = 0;
       this.patch = 0;
       this.minor = 0;
       this.major++;
-      this.inc('pre');
+      this.inc('pre', identifier);
       break;
     case 'preminor':
       this.prerelease.length = 0;
       this.patch = 0;
       this.minor++;
-      this.inc('pre');
+      this.inc('pre', identifier);
       break;
     case 'prepatch':
       // If this is already a prerelease, it will bump to the next version
       // drop any prereleases that might already exist, since they are not
       // relevant at this point.
       this.prerelease.length = 0;
-      this.inc('patch');
-      this.inc('pre');
+      this.inc('patch', identifier);
+      this.inc('pre', identifier);
       break;
     // If the input is a non-prerelease version, this acts the same as
     // prepatch.
     case 'prerelease':
       if (this.prerelease.length === 0)
-        this.inc('patch');
-      this.inc('pre');
+        this.inc('patch', identifier);
+      this.inc('pre', identifier);
       break;
 
     case 'major':
@@ -417,7 +442,7 @@ SemVer.prototype.inc = function(release) {
       this.prerelease = [];
       break;
     // This probably shouldn't be used publicly.
-    // 1.0.0 "pre" would become 1.0.0 which is the wrong direction.
+    // 1.0.0 "pre" would become 1.0.0-0 which is the wrong direction.
     case 'pre':
       if (this.prerelease.length === 0)
         this.prerelease = [0];
@@ -432,6 +457,15 @@ SemVer.prototype.inc = function(release) {
         if (i === -1) // didn't increment anything
           this.prerelease.push(0);
       }
+      if (identifier) {
+        // 1.2.0-beta.1 bumps to 1.2.0-beta.2,
+        // 1.2.0-beta.fooblz or 1.2.0-beta bumps to 1.2.0-beta.0
+        if (this.prerelease[0] === identifier) {
+          if (isNaN(this.prerelease[1]))
+            this.prerelease = [identifier, 0];
+        } else
+          this.prerelease = [identifier, 0];
+      }
       break;
 
     default:
@@ -442,14 +476,46 @@ SemVer.prototype.inc = function(release) {
 };
 
 exports.inc = inc;
-function inc(version, release, loose) {
+function inc(version, release, loose, identifier) {
+  if (typeof(loose) === 'string') {
+    identifier = loose;
+    loose = undefined;
+  }
+
   try {
-    return new SemVer(version, loose).inc(release).version;
+    return new SemVer(version, loose).inc(release, identifier).version;
   } catch (er) {
     return null;
   }
 }
 
+exports.diff = diff;
+function diff(version1, version2) {
+  if (eq(version1, version2)) {
+    return null;
+  } else {
+    var v1 = parse(version1);
+    var v2 = parse(version2);
+    if (v1.prerelease.length || v2.prerelease.length) {
+      for (var key in v1) {
+        if (key === 'major' || key === 'minor' || key === 'patch') {
+          if (v1[key] !== v2[key]) {
+            return 'pre'+key;
+          }
+        }
+      }
+      return 'prerelease';
+    }
+    for (var key in v1) {
+      if (key === 'major' || key === 'minor' || key === 'patch') {
+        if (v1[key] !== v2[key]) {
+          return key;
+        }
+      }
+    }
+  }
+}
+
 exports.compareIdentifiers = compareIdentifiers;
 
 var numeric = /^[0-9]+$/;
@@ -474,6 +540,21 @@ function rcompareIdentifiers(a, b) {
   return compareIdentifiers(b, a);
 }
 
+exports.major = major;
+function major(a, loose) {
+  return new SemVer(a, loose).major;
+}
+
+exports.minor = minor;
+function minor(a, loose) {
+  return new SemVer(a, loose).minor;
+}
+
+exports.patch = patch;
+function patch(a, loose) {
+  return new SemVer(a, loose).patch;
+}
+
 exports.compare = compare;
 function compare(a, b, loose) {
   return new SemVer(a, loose).compare(b);
diff --git a/test/big-numbers.js b/test/big-numbers.js
new file mode 100644
index 00000000..692aa241
--- /dev/null
+++ b/test/big-numbers.js
@@ -0,0 +1,24 @@
+var test = require('tap').test
+var semver = require('../')
+
+test('long version is too long', function (t) {
+  var v = '1.2.' + new Array(256).join('1')
+  t.throws(function () {
+    new semver.SemVer(v)
+  })
+  t.equal(semver.valid(v, false), null)
+  t.equal(semver.valid(v, true), null)
+  t.equal(semver.inc(v, 'patch'), null)
+  t.end()
+})
+
+test('big number is like too long version', function (t) {
+  var v = '1.2.' + new Array(100).join('1')
+  t.throws(function () {
+    new semver.SemVer(v)
+  })
+  t.equal(semver.valid(v, false), null)
+  t.equal(semver.valid(v, true), null)
+  t.equal(semver.inc(v, 'patch'), null)
+  t.end()
+})
diff --git a/test/index.js b/test/index.js
index 68d55daa..926d560f 100644
--- a/test/index.js
+++ b/test/index.js
@@ -13,6 +13,7 @@ var lte = semver.lte;
 var satisfies = semver.satisfies;
 var validRange = semver.validRange;
 var inc = semver.inc;
+var diff = semver.diff;
 var replaceStars = semver.replaceStars;
 var toComparators = semver.toComparators;
 var SemVer = semver.SemVer;
@@ -49,7 +50,9 @@ test('\ncomparison tests', function(t) {
     ['1.2.3-a.10', '1.2.3-a.5'],
     ['1.2.3-a.b', '1.2.3-a.5'],
     ['1.2.3-a.b', '1.2.3-a'],
-    ['1.2.3-a.b.c.10.d.5', '1.2.3-a.b.c.5.d.100']
+    ['1.2.3-a.b.c.10.d.5', '1.2.3-a.b.c.5.d.100'],
+    ['1.2.3-r2', '1.2.3-r100'],
+    ['1.2.3-r100', '1.2.3-R2']
   ].forEach(function(v) {
     var v0 = v[0];
     var v1 = v[1];
@@ -313,8 +316,8 @@ test('\nnegative range tests', function(t) {
 });
 
 test('\nincrement versions test', function(t) {
-  // [version, inc, result]
-  // inc(version, inc) -> result
+//  [version, inc, result, identifier]
+//  inc(version, inc) -> result
   [['1.2.3', 'major', '2.0.0'],
     ['1.2.3', 'minor', '1.3.0'],
     ['1.2.3', 'patch', '1.2.4'],
@@ -353,14 +356,87 @@ test('\nincrement versions test', function(t) {
     ['1.2.0', 'premajor', '2.0.0-0'],
     ['1.2.3-1', 'premajor', '2.0.0-0'],
     ['1.2.0-1', 'minor', '1.2.0'],
-    ['1.0.0-1', 'major', '1.0.0']
+    ['1.0.0-1', 'major', '1.0.0'],
+
+    ['1.2.3', 'major', '2.0.0', false, 'dev'],
+    ['1.2.3', 'minor', '1.3.0', false, 'dev'],
+    ['1.2.3', 'patch', '1.2.4', false, 'dev'],
+    ['1.2.3tag', 'major', '2.0.0', true, 'dev'],
+    ['1.2.3-tag', 'major', '2.0.0', false, 'dev'],
+    ['1.2.3', 'fake', null, false, 'dev'],
+    ['1.2.0-0', 'patch', '1.2.0', false, 'dev'],
+    ['fake', 'major', null, false, 'dev'],
+    ['1.2.3-4', 'major', '2.0.0', false, 'dev'],
+    ['1.2.3-4', 'minor', '1.3.0', false, 'dev'],
+    ['1.2.3-4', 'patch', '1.2.3', false, 'dev'],
+    ['1.2.3-alpha.0.beta', 'major', '2.0.0', false, 'dev'],
+    ['1.2.3-alpha.0.beta', 'minor', '1.3.0', false, 'dev'],
+    ['1.2.3-alpha.0.beta', 'patch', '1.2.3', false, 'dev'],
+    ['1.2.4', 'prerelease', '1.2.5-dev.0', false, 'dev'],
+    ['1.2.3-0', 'prerelease', '1.2.3-dev.0', false, 'dev'],
+    ['1.2.3-alpha.0', 'prerelease', '1.2.3-dev.0', false, 'dev'],
+    ['1.2.3-alpha.0', 'prerelease', '1.2.3-alpha.1', false, 'alpha'],
+    ['1.2.3-alpha.0.beta', 'prerelease', '1.2.3-dev.0', false, 'dev'],
+    ['1.2.3-alpha.0.beta', 'prerelease', '1.2.3-alpha.1.beta', false, 'alpha'],
+    ['1.2.3-alpha.10.0.beta', 'prerelease', '1.2.3-dev.0', false, 'dev'],
+    ['1.2.3-alpha.10.0.beta', 'prerelease', '1.2.3-alpha.10.1.beta', false, 'alpha'],
+    ['1.2.3-alpha.10.1.beta', 'prerelease', '1.2.3-alpha.10.2.beta', false, 'alpha'],
+    ['1.2.3-alpha.10.2.beta', 'prerelease', '1.2.3-alpha.10.3.beta', false, 'alpha'],
+    ['1.2.3-alpha.10.beta.0', 'prerelease', '1.2.3-dev.0', false, 'dev'],
+    ['1.2.3-alpha.10.beta.0', 'prerelease', '1.2.3-alpha.10.beta.1', false, 'alpha'],
+    ['1.2.3-alpha.10.beta.1', 'prerelease', '1.2.3-alpha.10.beta.2', false, 'alpha'],
+    ['1.2.3-alpha.10.beta.2', 'prerelease', '1.2.3-alpha.10.beta.3', false, 'alpha'],
+    ['1.2.3-alpha.9.beta', 'prerelease', '1.2.3-dev.0', false, 'dev'],
+    ['1.2.3-alpha.9.beta', 'prerelease', '1.2.3-alpha.10.beta', false, 'alpha'],
+    ['1.2.3-alpha.10.beta', 'prerelease', '1.2.3-alpha.11.beta', false, 'alpha'],
+    ['1.2.3-alpha.11.beta', 'prerelease', '1.2.3-alpha.12.beta', false, 'alpha'],
+    ['1.2.0', 'prepatch', '1.2.1-dev.0', 'dev'],
+    ['1.2.0-1', 'prepatch', '1.2.1-dev.0', 'dev'],
+    ['1.2.0', 'preminor', '1.3.0-dev.0', 'dev'],
+    ['1.2.3-1', 'preminor', '1.3.0-dev.0', 'dev'],
+    ['1.2.0', 'premajor', '2.0.0-dev.0', 'dev'],
+    ['1.2.3-1', 'premajor', '2.0.0-dev.0', 'dev'],
+    ['1.2.0-1', 'minor', '1.2.0', 'dev'],
+    ['1.0.0-1', 'major', '1.0.0', 'dev'],
+    ['1.2.3-dev.bar', 'prerelease', '1.2.3-dev.0', false, 'dev']
+
   ].forEach(function(v) {
     var pre = v[0];
     var what = v[1];
     var wanted = v[2];
     var loose = v[3];
-    var found = inc(pre, what, loose);
-    t.equal(found, wanted, 'inc(' + pre + ', ' + what + ') === ' + wanted);
+    var id = v[4];
+    var found = inc(pre, what, loose, id);
+    var cmd = 'inc(' + pre + ', ' + what + ', ' + id + ')';
+    t.equal(found, wanted, cmd + ' === ' + wanted);
+  });
+
+  t.end();
+});
+
+test('\ndiff versions test', function(t) {
+//  [version1, version2, result]
+//  diff(version1, version2) -> result
+  [['1.2.3', '0.2.3', 'major'],
+    ['1.4.5', '0.2.3', 'major'],
+    ['1.2.3', '2.0.0-pre', 'premajor'],
+    ['1.2.3', '1.3.3', 'minor'],
+    ['1.0.1', '1.1.0-pre', 'preminor'],
+    ['1.2.3', '1.2.4', 'patch'],
+    ['1.2.3', '1.2.4-pre', 'prepatch'],
+    ['0.0.1', '0.0.1-pre', 'prerelease'],
+    ['0.0.1', '0.0.1-pre-2', 'prerelease'],
+    ['1.1.0', '1.1.0-pre', 'prerelease'],
+    ['1.1.0-pre-1', '1.1.0-pre-2', 'prerelease'],
+    ['1.0.0', '1.0.0', null]
+
+  ].forEach(function(v) {
+    var version1 = v[0];
+    var version2 = v[1];
+    var wanted = v[2];
+    var found = diff(version1, version2);
+    var cmd = 'diff(' + version1 + ', ' + version2 + ')';
+    t.equal(found, wanted, cmd + ' === ' + wanted);
   });
 
   t.end();
diff --git a/test/major-minor-patch.js b/test/major-minor-patch.js
new file mode 100644
index 00000000..e9d4039c
--- /dev/null
+++ b/test/major-minor-patch.js
@@ -0,0 +1,72 @@
+var tap = require('tap');
+var test = tap.test;
+var semver = require('../semver.js');
+
+test('\nmajor tests', function(t) {
+  // [range, version]
+  // Version should be detectable despite extra characters
+  [
+    ['1.2.3', 1],
+    [' 1.2.3 ', 1],
+    [' 2.2.3-4 ', 2],
+    [' 3.2.3-pre ', 3],
+    ['v5.2.3', 5],
+    [' v8.2.3 ', 8],
+    ['\t13.2.3', 13],
+    ['=21.2.3', 21, true],
+    ['v=34.2.3', 34, true]
+  ].forEach(function(tuple) {
+    var range = tuple[0];
+    var version = tuple[1];
+    var loose = tuple[2] || false;
+    var msg = 'major(' + range + ') = ' + version;
+    t.equal(semver.major(range, loose), version, msg);
+  });
+  t.end();
+});
+
+test('\nminor tests', function(t) {
+  // [range, version]
+  // Version should be detectable despite extra characters
+  [
+    ['1.1.3', 1],
+    [' 1.1.3 ', 1],
+    [' 1.2.3-4 ', 2],
+    [' 1.3.3-pre ', 3],
+    ['v1.5.3', 5],
+    [' v1.8.3 ', 8],
+    ['\t1.13.3', 13],
+    ['=1.21.3', 21, true],
+    ['v=1.34.3', 34, true]
+  ].forEach(function(tuple) {
+    var range = tuple[0];
+    var version = tuple[1];
+    var loose = tuple[2] || false;
+    var msg = 'minor(' + range + ') = ' + version;
+    t.equal(semver.minor(range, loose), version, msg);
+  });
+  t.end();
+});
+
+test('\npatch tests', function(t) {
+  // [range, version]
+  // Version should be detectable despite extra characters
+  [
+    ['1.2.1', 1],
+    [' 1.2.1 ', 1],
+    [' 1.2.2-4 ', 2],
+    [' 1.2.3-pre ', 3],
+    ['v1.2.5', 5],
+    [' v1.2.8 ', 8],
+    ['\t1.2.13', 13],
+    ['=1.2.21', 21, true],
+    ['v=1.2.34', 34, true]
+  ].forEach(function(tuple) {
+    var range = tuple[0];
+    var version = tuple[1];
+    var loose = tuple[2] || false;
+    var msg = 'patch(' + range + ') = ' + version;
+    t.equal(semver.patch(range, loose), version, msg);
+  });
+  t.end();
+});