Kotlin conversion: DateUtil

pgpainless-core/src/main/kotlin/openpgp/DateExtensions.kt

@@ -4,20 +4,53 @@
 
 package openpgp
 
+import java.text.ParseException
+import java.text.SimpleDateFormat
 import java.util.*
 
-    /**
-     * Return a new date which represents this date plus the given amount of seconds added.
-     *
-     * Since '0' is a special date value in the OpenPGP specification
-     * (e.g. '0' means no expiration for expiration dates), this method will return 'null' if seconds is 0.
-     *
-     * @param date date
-     * @param seconds number of seconds to be added
-     * @return date plus seconds or null if seconds is '0'
-     */
-    fun Date.plusSeconds(seconds: Long): Date? {
-        require(Long.MAX_VALUE - time > seconds) { "Adding $seconds seconds to this date would cause time to overflow." }
-        return if (seconds == 0L) null
-        else Date(this.time + 1000 * seconds)
+/**
+ * Return a new date which represents this date plus the given amount of seconds added.
+ *
+ * Since '0' is a special date value in the OpenPGP specification
+ * (e.g. '0' means no expiration for expiration dates), this method will return 'null' if seconds is 0.
+ *
+ * @param date date
+ * @param seconds number of seconds to be added
+ * @return date plus seconds or null if seconds is '0'
+ */
+fun Date.plusSeconds(seconds: Long): Date? {
+    require(Long.MAX_VALUE - time > seconds) { "Adding $seconds seconds to this date would cause time to overflow." }
+    return if (seconds == 0L) null
+    else Date(this.time + 1000 * seconds)
+}
+
+/**
+ * Return a new [Date] instance with this instance's time floored down to seconds precision.
+ */
+fun Date.toSecondsPrecision(): Date {
+    return Date((time / 1000) * 1000)
+}
+
+internal val parser: SimpleDateFormat
+    // Java's SimpleDateFormat is not thread-safe, therefore we return a new instance on every invocation.
+    get() = SimpleDateFormat("yyyy-MM-dd HH:mm:ss z")
+            .apply { timeZone = TimeZone.getTimeZone("UTC") }
+
+/**
+ * Format a date as UTC timestamp.
+ *
+ * @return timestamp
+ */
+fun Date.formatUTC(): String = parser.format(this)
+
+/**
+ * Parse a UTC timestamp into a date.
+ * @return date
+ */
+fun String.parseUTC(): Date {
+    return try {
+        parser.parse(this)
+    } catch (e : ParseException) {
+        throw IllegalArgumentException("Malformed UTC timestamp: $this", e)
     }
+}