feat: PGP decrypt works

src/util.rs

@@ -1,3 +1,33 @@
+use std::io;
+use std::io::Write;
+
+use base64::Engine;
+use base64::engine::general_purpose;
+use rust_util::{warning, XResult};
+
+pub const TINY_ENC_FILE_EXT: &str = ".tinyenc";
+
+pub fn decode_base64(input: &str) -> XResult<Vec<u8>> {
+    Ok(general_purpose::STANDARD.decode(input)?)
+}
+
+pub fn read_number(hint: &str, from: usize, to: usize) -> usize {
+    loop {
+        print!("{} ({}-{}): ", hint, from, to);
+        io::stdout().flush().ok();
+        let mut buff = String::new();
+        let _ = io::stdin().read_line(&mut buff).expect("Read line from stdin");
+        let buff = buff.trim();
+        match buff.parse() {
+            Err(_) => warning!("Input number error!"),
+            Ok(number) => if number < from || number > to {
+                warning!("Input number is not in range.");
+            } else {
+                return number;
+            },
+        }
+    }
+}
 
 pub fn get_user_agent() -> String {
     format!("TinyEncrypt-rs v{}@{}", env!("CARGO_PKG_VERSION"),