implemented hostnames_allocator

hostnames_allocator/Cargo.toml

@@ -6,5 +6,8 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+lazy_static = "1.4.0"
+regex = "1.10.2"
+
 [dev-dependencies]
 itertools = "0.11.0"

hostnames_allocator/src/hostnames_allocator.rs

@@ -0,0 +1,36 @@
+use std::collections::HashMap;
+
+use lazy_static::lazy_static;
+use regex::Regex;
+
+use crate::ranged_number_allocator::RangedNumberAllocator;
+
+pub struct HostnamesAllocator {
+    allocators_by_type: HashMap<String, RangedNumberAllocator>,
+}
+
+lazy_static! {
+    static ref HOST_NAME_REGEX: Regex = Regex::new(r"^(\D+)(\d+)$").unwrap();
+}
+
+impl HostnamesAllocator {
+    pub fn new() -> HostnamesAllocator {
+        HostnamesAllocator { allocators_by_type: HashMap::new() }
+    }
+
+    fn get_allocator_for_host_type(&mut self, host_type: &str) -> &mut RangedNumberAllocator {
+        self.allocators_by_type.entry(host_type.into()).or_insert_with(|| RangedNumberAllocator::new())
+    }
+
+    pub fn allocate(&mut self, host_type: &str) -> String {
+        let allocator = self.get_allocator_for_host_type(host_type);
+        let number = allocator.allocate();
+        return format!("{host_type}{number}");
+    }
+
+    pub fn free(&mut self, host_name: &str) {
+        let (_, [host_type, host_number]) = HOST_NAME_REGEX.captures(host_name).unwrap().extract();
+        let allocator = self.get_allocator_for_host_type(host_type);
+        allocator.remove(host_number.parse().unwrap());
+    }
+}

hostnames_allocator/src/lib.rs

@@ -1,3 +1,4 @@
 #![feature(btree_cursors)]
 
+pub mod hostnames_allocator;
 pub mod ranged_number_allocator;

hostnames_allocator/tests/hostnames_allocator.rs

@@ -0,0 +1,19 @@
+extern crate hostnames_allocator;
+
+use hostnames_allocator::hostnames_allocator::HostnamesAllocator;
+
+#[test]
+fn allocator_allocates_hostnames() {
+    let mut allocator = HostnamesAllocator::new();
+    assert_eq!(allocator.allocate("gateway"), "gateway1");
+    assert_eq!(allocator.allocate("gateway"), "gateway2");
+    assert_eq!(allocator.allocate("gateway"), "gateway3");
+    assert_eq!(allocator.allocate("proxy"), "proxy1");
+    assert_eq!(allocator.allocate("proxy"), "proxy2");
+    allocator.free("gateway2");
+    allocator.free("gateway5");
+    assert_eq!(allocator.allocate("proxy"), "proxy3");
+    assert_eq!(allocator.allocate("gateway"), "gateway2");
+    assert_eq!(allocator.allocate("gateway"), "gateway4");
+    assert_eq!(allocator.allocate("gateway"), "gateway5");
+}