taler-util: parse duration strings

packages/taler-util/src/time.test.ts

@@ -0,0 +1,39 @@
+/*
+ This file is part of GNU Taler
+ (C) 2019 GNUnet e.V.
+
+ 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/>
+ */
+
+import test from "ava";
+import { Duration } from "./time.js";
+
+test("duration parsing", (t) => {
+  const d1 = Duration.fromPrettyString("1h");
+  t.deepEqual(d1.d_ms, 60 * 60 * 1000);
+
+  const d2 = Duration.fromPrettyString("  2h 1s 3m");
+  t.deepEqual(d2.d_ms, 2 * 60 * 60 * 1000 + 3 * 60 * 1000 + 1000);
+
+  t.throws(() => {
+    Duration.fromPrettyString("5g");
+  });
+  t.throws(() => {
+    Duration.fromPrettyString("s");
+  });
+  t.throws(() => {
+    Duration.fromPrettyString("s5");
+  });
+  t.throws(() => {
+    Duration.fromPrettyString("5 5 s");
+  });
+});

packages/taler-util/src/time.ts

@@ -113,6 +113,49 @@ export namespace Duration {
     return { d_ms: deadline.t_ms - now.t_ms };
   }
 
+  export function fromPrettyString(s: string): Duration {
+    let dMs = 0;
+    let currentNum = "";
+    let parsingNum = true;
+    for (let i = 0; i < s.length; i++) {
+      const cc = s.charCodeAt(i);
+      if (cc >= "0".charCodeAt(0) && cc <= "9".charCodeAt(0)) {
+        if (!parsingNum) {
+          throw Error("invalid duration, unexpected number");
+        }
+        currentNum += s[i];
+        continue;
+      }
+      if (s[i] == " ") {
+        if (currentNum != "") {
+          parsingNum = false;
+        }
+        continue;
+      }
+
+      if (currentNum == "") {
+        throw Error("invalid duration, missing number");
+      }
+
+      if (s[i] === "s") {
+        dMs += 1000 * Number.parseInt(currentNum, 10);
+      } else if (s[i] === "m") {
+        dMs += 60 * 1000 * Number.parseInt(currentNum, 10);
+      } else if (s[i] === "h") {
+        dMs += 60 * 60 * 1000 * Number.parseInt(currentNum, 10);
+      } else if (s[i] === "d") {
+        dMs += 24 * 60 * 60 * 1000 * Number.parseInt(currentNum, 10);
+      } else {
+        throw Error("invalid duration, unsupported unit");
+      }
+      currentNum = "";
+      parsingNum = true;
+    }
+    return {
+      d_ms: dMs,
+    };
+  }
+
   export function max(d1: Duration, d2: Duration): Duration {
     return durationMax(d1, d2);
   }