Implement hash table lookup logic

src/table.zig

@@ -2,23 +2,20 @@ const std = @import("std");
 
 pub fn Dynamic(comptime Key: type, comptime Value: type, comptime key_context: KeyContext(Key)) type {
     return struct {
+        load_maximum: f32,
         buckets_used: usize,
-        bucket_map: []?Bucket,
+        buckets: []Bucket,
 
         ///
         ///
         ///
         const Bucket = struct {
-            key: Key,
-            value: Value,
-            next: ?usize,
-        };
-
-        ///
-        ///
-        ///
-        pub const InsertError = error {
+            maybe_entry: ?struct {
+                key: Key,
+                value: Value,
+            },
 
+            maybe_next_index: ?usize,
         };
 
         ///
@@ -29,8 +26,7 @@ pub fn Dynamic(comptime Key: type, comptime Value: type, comptime key_context: K
         ///
         ///
         ///
-        pub fn insert(self: Self, key: Key, value: Value) InsertError!void {
-            _ = value;
+        pub fn delete(self: Self, key: Key) bool {
             _ = key;
             _ = self;
         }
@@ -38,14 +34,43 @@ pub fn Dynamic(comptime Key: type, comptime Value: type, comptime key_context: K
         ///
         ///
         ///
+        pub fn insert(self: Self, key: Key, value: Value) InsertError!void {
+            if ((@intToFloat(f32, self.buckets_used) / @intToFloat(
+                f32, self.buckets.len)) >= self.load_maximum) try self.rehash();
+
+            var hash = @mod(key_context.hash(key), self.buckets.len);
+
+            while (true) {
+                const bucket = &(self.buckets[hash]);
+
+                const entry = &(bucket.maybe_entry orelse {
+                    bucket.maybe_entry = .{
+                        .key = key,
+                        .value = value
+                    };
+                });
+
+                if (key_context.equals(entry.key, key)) return error.KeyExists;
+
+                hash = @mod(hashHash(hash), self.buckets.len);
+            }
+        }
+
+        ///
+        /// Searches for a value indexed with `key` in `self`, returning it or `null` if no matching
+        /// entry was found.
+        ///
         pub fn lookup(self: Self, key: Key) ?*Value {
-            var bucket = &(self.bucket_map[@mod(key_context.hash(
-                key), self.bucket_map.len)] orelse return null);
+            var bucket = &(self.buckets[@mod(key_context.hash(key), self.buckets.len)]);
 
-            while (bucket) {
-                if (key_context.equals(bucket.key, key)) return &bucket.value;
+            if (bucket.maybe_entry) |*entry|
+                if (key_context.equals(entry.key, key)) return &entry.value;
 
-                bucket = bucket.next;
+            while (bucket.maybe_next_index) |index| {
+                bucket = &(self.buckets[index]);
+
+                if (bucket.maybe_entry) |*entry|
+                    if (key_context.equals(entry.key, key)) return &entry.value;
             }
 
             return null;
@@ -53,6 +78,13 @@ pub fn Dynamic(comptime Key: type, comptime Value: type, comptime key_context: K
     };
 }
 
+///
+///
+///
+pub const InsertError = std.mem.Allocator || error {
+    KeyExists,
+};
+
 pub fn KeyContext(comptime Key: type) type {
     return struct {
         hash: fn (Key) usize,