From 755dc5619dd9f545ec7b4441bc3b2a99a0fb1ffd Mon Sep 17 00:00:00 2001
From: Hatter Jiang <jht5945@gmail.com>
Date: Sun, 8 Nov 2020 22:58:31 +0800
Subject: [PATCH] feat: add parse_duration

---
 src/util_time.rs | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/src/util_time.rs b/src/util_time.rs
index deee5d8..a4070e1 100644
--- a/src/util_time.rs
+++ b/src/util_time.rs
@@ -1,4 +1,5 @@
 use std::time::SystemTime;
+use std::time::Duration;
 
 pub fn get_current_secs() -> u64 {
     SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).map(|d| d.as_secs()).unwrap_or(0 /* SHOULD NOT HAPPEN */ )
@@ -7,3 +8,35 @@ pub fn get_current_secs() -> u64 {
 pub fn get_current_millis() -> u128 {
     SystemTime::now().duration_since(SystemTime::UNIX_EPOCH).map(|d| d.as_millis()).unwrap_or(0 /* SHOULD NOT HAPPEN */ )
 }
+
+pub fn parse_duration(t: &str) -> Option<Duration> {
+    if t.is_empty() {
+        return None;
+    }
+    let parse_and_process_time = |mul: u32| {
+        t[..t.len() - 1].parse::<f64>().map(|ti| Duration::from_millis((ti * mul as f64) as u64)).ok()
+    };
+    match t.to_ascii_lowercase().chars().last() {
+        Some('s') => parse_and_process_time(1000),
+        Some('m') => parse_and_process_time(60 * 1000),
+        Some('h') => parse_and_process_time(60 * 60 * 1000),
+        Some('d') => parse_and_process_time(24 * 60 * 60 * 1000),
+        _ => t.parse::<u64>().map(|t| Duration::from_millis(t)).ok(),
+    }
+}
+
+#[test]
+fn test_parse_duration() {
+    assert_eq!(None, parse_duration(""));
+    assert_eq!(None, parse_duration("X"));
+    assert_eq!(None, parse_duration("S"));
+    assert_eq!(Duration::from_millis(1), parse_duration("1").unwrap());
+    assert_eq!(Duration::from_millis(100), parse_duration("100").unwrap());
+    assert_eq!(Duration::from_millis(1000), parse_duration("1s").unwrap());
+    assert_eq!(Duration::from_millis(2000), parse_duration("2S").unwrap());
+    assert_eq!(Duration::from_millis(1500), parse_duration("1.5s").unwrap());
+    assert_eq!(Duration::from_millis(60000), parse_duration("1m").unwrap());
+    assert_eq!(Duration::from_millis(3600000), parse_duration("1h").unwrap());
+    assert_eq!(Duration::from_millis(1800000), parse_duration("0.5h").unwrap());
+    assert_eq!(Duration::from_millis(24*3600000), parse_duration("1d").unwrap());
+}
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