Set array capacity and use appendAssumeCapacity

Author: marselester

src/decoder.zig

@@ -191,7 +191,7 @@ pub const Decoder = struct {
                     const Value = std.meta.FieldType(DecodedType.KV, .value);
                     var map = DecodedType.init(allocator);
                     const map_len = field.size;
-                    try map.ensureTotalCapacity(@intCast(map_len));
+                    try map.ensureTotalCapacity(map_len);
 
                     for (0..map_len) |_| {
                         const key = try self.decodeValue(allocator, Key);
@@ -209,11 +209,12 @@ pub const Decoder = struct {
                     }
 
                     const Value = std.meta.Child(DecodedType.Slice);
-                    var array = std.ArrayList(Value).init(allocator);
                     const array_len = field.size;
+                    var array = try std.ArrayList(Value).initCapacity(allocator, array_len);
+
                     for (0..array_len) |_| {
                         const value = try self.decodeValue(allocator, Value);
-                        try array.append(value);
+                        array.appendAssumeCapacity(value);
                     }
 
                     return array;

src/maxminddb.zig

@@ -17,7 +17,7 @@ test {
 }
 
 fn expectEqualMaps(
-    map: std.hash_map.StringHashMap([]const u8),
+    map: std.StringArrayHashMap([]const u8),
     keys: []const []const u8,
     values: []const []const u8,
 ) !void {

src/reader.zig

@@ -175,7 +175,7 @@ pub const Reader = struct {
         // start with the node we traversed to as our to be processed stack.
         // Else the stack will be empty and we'll be returning an iterator that visits nothing.
         if (node < node_count) {
-            try stack.append(WithinNode{
+            stack.appendAssumeCapacity(WithinNode{
                 .node = node,
                 .ip_bytes = ip_bytes,
                 .prefix_len = prefix_len,
@@ -360,15 +360,15 @@ fn Iterator(comptime T: type) type {
                         }
                     }
 
-                    try self.stack.append(WithinNode{
+                    self.stack.appendAssumeCapacity(WithinNode{
                         .node = node,
                         .ip_bytes = right_ip_bytes,
                         .prefix_len = current.prefix_len + 1,
                     });
 
                     // In order traversal of the children on the left (0-bit).
                     node = try reader.readNode(current.node, 0);
-                    try self.stack.append(WithinNode{
+                    self.stack.appendAssumeCapacity(WithinNode{
                         .node = node,
                         .ip_bytes = current.ip_bytes,
                         .prefix_len = current.prefix_len + 1,