Pattern generator.

1 files changed, 36 insertions, 0 deletions

diff --git a/passwords.rs b/passwords.rs
new file mode 100644
index 0000000..533e282
--- /dev/null
+++ b/passwords.rs
@@ -0,0 +1,36 @@
+use std::io::{self, Write};
+use std::iter;
+
+fn make_passwords<W: Write>(patterns: &[Vec<u8>],
+                            buffer: &mut Vec<u8>,
+                            i: usize,
+                            writer: &mut W) {
+    if i == patterns.len() {
+        writer.write(&buffer).unwrap();
+    } else {
+        for c in patterns[i].iter() {
+            buffer[i] = *c;
+            make_passwords(patterns, buffer, i+1, writer);
+        }
+    }
+}
+
+fn main() {
+    let range = |a, b| {
+        (a as u8 .. b as u8 + 1).collect::<Vec<_>>()
+    };
+
+    let patterns: Vec<Vec<u8>> = vec!(
+        range('a', 'z'),
+        range('1', '9'),
+        range('a', 'z'),
+        range('a', 'z'),
+        range('a', 'z'),
+    );
+
+  let mut buffer: Vec<u8> = vec!(0; patterns.len() + 1);
+  buffer[patterns.len()] = '\n' as u8;
+
+  let mut writer = io::BufWriter::new(io::stdout());
+  make_passwords(&patterns, &mut buffer, 0, &mut writer);
+}