1 files changed, 105 insertions, 0 deletions
diff --git a/taler-kotlin-android/src/main/java/net/taler/common/Time.kt b/taler-kotlin-android/src/main/java/net/taler/common/Time.kt
new file mode 100644
index 0000000..f280d5f
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+++ b/taler-kotlin-android/src/main/java/net/taler/common/Time.kt
@@ -0,0 +1,105 @@
+/*
+ * This file is part of GNU Taler
+ * (C) 2020 Taler Systems S.A.
+ *
+ * GNU Taler is free software; you can redistribute it and/or modify it under the
+ * terms of the GNU General Public License as published by the Free Software
+ * Foundation; either version 3, or (at your option) any later version.
+ *
+ * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+ * A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+package net.taler.common
+
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonPrimitive
+import kotlinx.serialization.json.JsonTransformingSerializer
+import kotlinx.serialization.json.contentOrNull
+import kotlinx.serialization.json.jsonPrimitive
+import kotlinx.serialization.json.longOrNull
+import kotlin.math.max
+
+@Serializable
+data class Timestamp(
+    @SerialName("t_s")
+    @Serializable(NeverSerializer::class)
+    private val s: Long,
+) : Comparable<Timestamp> {
+
+    companion object {
+        private const val NEVER: Long = -1
+        fun now(): Timestamp = fromMillis(System.currentTimeMillis())
+        fun never(): Timestamp = Timestamp(NEVER)
+        fun fromMillis(ms: Long) = Timestamp(ms / 1000L)
+    }
+
+    val ms: Long = s * 1000L
+
+    operator fun minus(other: Timestamp): RelativeTime = when {
+        ms == NEVER -> RelativeTime.fromMillis(RelativeTime.FOREVER)
+        other.ms == NEVER -> throw Error("Invalid argument for timestamp comparison")
+        ms < other.ms -> RelativeTime.fromMillis(0)
+        else -> RelativeTime.fromMillis(ms - other.ms)
+    }
+
+    operator fun minus(other: RelativeTime): Timestamp = when {
+        ms == NEVER -> this
+        other.ms == RelativeTime.FOREVER -> fromMillis(0)
+        else -> fromMillis(max(0, ms - other.ms))
+    }
+
+    override fun compareTo(other: Timestamp): Int {
+        return if (ms == NEVER) {
+            if (other.ms == NEVER) 0
+            else 1
+        } else {
+            if (other.ms == NEVER) -1
+            else ms.compareTo(other.ms)
+        }
+    }
+
+}
+
+@Serializable
+data class RelativeTime(
+    /**
+     * Duration in microseconds or "forever" to represent an infinite duration.
+     * Numeric values are capped at 2^53 - 1 inclusive.
+     */
+    @SerialName("d_us")
+    @Serializable(ForeverSerializer::class)
+    private val s: Long,
+) {
+    val ms: Long = s * 1000L
+
+    companion object {
+        internal const val FOREVER: Long = -1
+        fun forever(): RelativeTime = fromMillis(FOREVER)
+        fun fromMillis(ms: Long) = RelativeTime(ms / 100L)
+    }
+}
+
+internal abstract class MinusOneSerializer(private val keyword: String) :
+    JsonTransformingSerializer<Long>(Long.serializer()) {
+
+    override fun transformDeserialize(element: JsonElement): JsonElement {
+        return if (element.jsonPrimitive.contentOrNull == keyword) return JsonPrimitive(-1)
+        else super.transformDeserialize(element)
+    }
+
+    override fun transformSerialize(element: JsonElement): JsonElement {
+        return if (element.jsonPrimitive.longOrNull == -1L) return JsonPrimitive(keyword)
+        else element
+    }
+}
+
+internal object NeverSerializer : MinusOneSerializer("never")
+internal object ForeverSerializer : MinusOneSerializer("forever")