Support multiple threads for vanity address

cli/src/main.rs

@@ -42,6 +42,11 @@ fn main() {
                 .long("vanity")
                 .help("Generate a vanity address with the given prefix")
                 .takes_value(true))
+        .arg(Arg::with_name("threads")
+                .long("threads")
+                .help("Number of threads to use for the vanity address generator. Set this to the number of CPUs you have")
+                .takes_value(true)
+                .default_value("1"))
         .arg(Arg::with_name("t_addresses")
                 .short("t")
                 .long("taddrs")
@@ -94,7 +99,6 @@ fn main() {
     // Number of z addresses to generate
     let z_addresses = matches.value_of("z_addresses").unwrap().parse::<u32>().unwrap();    
 
-
     let addresses = if !matches.value_of("vanity").is_none() {
         if z_addresses != 1 {
             eprintln!("Can only generate 1 zaddress in vanity mode. You specified {}", z_addresses);
@@ -106,9 +110,11 @@ fn main() {
             return;
         }
 
+        let num_threads = matches.value_of("threads").unwrap().parse::<u32>().unwrap();
+
         let prefix = matches.value_of("vanity").unwrap().to_string();
         println!("Generating address starting with \"{}\"", prefix);
-        let addresses = generate_vanity_wallet(is_testnet, prefix);
+        let addresses = generate_vanity_wallet(is_testnet, num_threads, prefix);
 
         // return
         addresses

lib/src/paper.rs

@@ -126,7 +126,7 @@ pub fn vanity_thread(is_testnet: bool, entropy: &[u8], prefix: String, tx: mpsc:
 }
 
 /// Generate a vanity address with the given prefix.
-pub fn generate_vanity_wallet(is_testnet: bool, prefix: String) -> String {
+pub fn generate_vanity_wallet(is_testnet: bool, num_threads: u32, prefix: String) -> String {
     // Get 32 bytes of system entropy
     let mut system_rng = ChaChaRng::from_entropy();    
 
@@ -135,7 +135,7 @@ pub fn generate_vanity_wallet(is_testnet: bool, prefix: String) -> String {
 
     let mut handles = Vec::new();
 
-    for _i in 0..8 {
+    for _i in 0..num_threads {
         let testnet_local = is_testnet.clone();
         let prefix_local = prefix.clone();
         let tx_local = mpsc::Sender::clone(&tx);
@@ -159,7 +159,7 @@ pub fn generate_vanity_wallet(is_testnet: bool, prefix: String) -> String {
         let recv = rx.recv().unwrap();
         if recv.starts_with(&"Processed") {
             processed = processed + 1000;
-            let timeelapsed = now.elapsed().unwrap().as_secs();
+            let timeelapsed = now.elapsed().unwrap().as_secs() + 1; // Add one second to prevent any divide by zero problems.
 
             print!("Checking addresses at {}/sec \r", (processed / timeelapsed));
             io::stdout().flush().ok().unwrap();