29 generalized time bug (#30)

* Fix #29 :: ParseGeneralizedTime should explicitly use int64

* Add missing comment doc

* Travis Updates

* Update travis test matrix

.travis.yml

@@ -1,39 +1,39 @@
 language: go
-matrix:
+
+go:
+  - 1.2.x
+  - 1.6.x
+  - 1.9.x
+  - 1.10.x
+  - 1.11.x
+  - 1.12.x
+  - 1.14.x
+  - tip
+
+os:
+  - linux
+
+arch:
+  - amd64
+
+dist: xenial
+
+env:
+  - GOARCH=amd64
+
+jobs:
   include:
-    - go: 1.2.x
-      env: GOOS=linux GOARCH=amd64
-    - go: 1.2.x
-      env: GOOS=linux GOARCH=386
-    - go: 1.2.x
-      env: GOOS=windows GOARCH=amd64
-    - go: 1.2.x
-      env: GOOS=windows GOARCH=386
-    - go: 1.3.x
-    - go: 1.4.x
-    - go: 1.5.x
-    - go: 1.6.x
-    - go: 1.7.x
-    - go: 1.8.x
-    - go: 1.9.x
-    - go: 1.10.x
-    - go: 1.11.x
-    - go: 1.12.x
-    - go: 1.13.x
-    - go: 1.14.x
-      env: GOOS=linux GOARCH=amd64
-    - go: 1.14.x
-      env: GOOS=linux GOARCH=386
-    - go: 1.14.x
-      env: GOOS=windows GOARCH=amd64
-    - go: 1.14.x
-      env: GOOS=windows GOARCH=386
-    - go: tip
-go_import_path: gopkg.in/asn-ber.v1
-install:
-  - go list -f '{{range .Imports}}{{.}} {{end}}' ./... | xargs go get -v
-  - go list -f '{{range .TestImports}}{{.}} {{end}}' ./... | xargs go get -v
-  - go get code.google.com/p/go.tools/cmd/cover || go get golang.org/x/tools/cmd/cover
-  - go build -v ./...
+    - os: windows
+      go: 1.14.x
+    - os: osx
+      go: 1.14.x
+    - os: linux
+      go: 1.14.x
+      arch: arm64
+    - os: linux
+      go: 1.14.x
+      env:
+        - GOARCH=386
+
 script:
   - go test -v -cover ./... || go test -v ./...

generalizedTime.go

@@ -13,6 +13,10 @@ var ErrInvalidTimeFormat = errors.New("invalid time format")
 
 var zeroTime = time.Time{}
 
+// ParseGeneralizedTime parses a string value and if it conforms to
+// GeneralizedTime[^0] format, will return a time.Time for that value.
+//
+// [^0]: https://www.itu.int/rec/T-REC-X.690-201508-I/en Section 11.7
 func ParseGeneralizedTime(v []byte) (time.Time, error) {
 	var format string
 	var fract time.Duration
@@ -59,10 +63,10 @@ func ParseGeneralizedTime(v []byte) (time.Time, error) {
 		tzIndex = dot
 
 		if dot == 10 {
-			fract = time.Duration(int(f * float64(time.Hour)))
+			fract = time.Duration(int64(f * float64(time.Hour)))
 			format = `2006010215Z`
 		} else {
-			fract = time.Duration(int(f * float64(time.Minute)))
+			fract = time.Duration(int64(f * float64(time.Minute)))
 			format = `200601021504Z`
 		}