104 lines
3.1 KiB
Zig
104 lines
3.1 KiB
Zig
const std = @import("std.zig");
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const HashMap = std.HashMap;
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const mem = std.mem;
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const Allocator = mem.Allocator;
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const testing = std.testing;
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/// BufMap copies keys and values before they go into the map, and
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/// frees them when they get removed.
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pub const BufMap = struct {
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hash_map: BufMapHashMap,
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const BufMapHashMap = HashMap([]const u8, []const u8, mem.hash_slice_u8, mem.eql_slice_u8);
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pub fn init(allocator: *Allocator) BufMap {
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var self = BufMap{ .hash_map = BufMapHashMap.init(allocator) };
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return self;
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}
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pub fn deinit(self: *BufMap) void {
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var it = self.hash_map.iterator();
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while (true) {
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const entry = it.next() orelse break;
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self.free(entry.key);
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self.free(entry.value);
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}
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self.hash_map.deinit();
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}
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/// Same as `set` but the key and value become owned by the BufMap rather
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/// than being copied.
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/// If `setMove` fails, the ownership of key and value does not transfer.
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pub fn setMove(self: *BufMap, key: []u8, value: []u8) !void {
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const get_or_put = try self.hash_map.getOrPut(key);
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if (get_or_put.found_existing) {
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self.free(get_or_put.kv.key);
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get_or_put.kv.key = key;
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}
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get_or_put.kv.value = value;
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}
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/// `key` and `value` are copied into the BufMap.
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pub fn set(self: *BufMap, key: []const u8, value: []const u8) !void {
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const value_copy = try self.copy(value);
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errdefer self.free(value_copy);
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// Avoid copying key if it already exists
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const get_or_put = try self.hash_map.getOrPut(key);
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if (!get_or_put.found_existing) {
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get_or_put.kv.key = self.copy(key) catch |err| {
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_ = self.hash_map.remove(key);
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return err;
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};
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}
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get_or_put.kv.value = value_copy;
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}
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pub fn get(self: BufMap, key: []const u8) ?[]const u8 {
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const entry = self.hash_map.get(key) orelse return null;
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return entry.value;
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}
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pub fn delete(self: *BufMap, key: []const u8) void {
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const entry = self.hash_map.remove(key) orelse return;
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self.free(entry.key);
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self.free(entry.value);
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}
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pub fn count(self: BufMap) usize {
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return self.hash_map.count();
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}
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pub fn iterator(self: *const BufMap) BufMapHashMap.Iterator {
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return self.hash_map.iterator();
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}
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fn free(self: BufMap, value: []const u8) void {
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self.hash_map.allocator.free(value);
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}
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fn copy(self: BufMap, value: []const u8) ![]u8 {
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return mem.dupe(self.hash_map.allocator, u8, value);
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}
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};
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test "BufMap" {
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var bufmap = BufMap.init(std.heap.direct_allocator);
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defer bufmap.deinit();
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try bufmap.set("x", "1");
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testing.expect(mem.eql(u8, bufmap.get("x").?, "1"));
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testing.expect(1 == bufmap.count());
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try bufmap.set("x", "2");
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testing.expect(mem.eql(u8, bufmap.get("x").?, "2"));
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testing.expect(1 == bufmap.count());
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try bufmap.set("x", "3");
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testing.expect(mem.eql(u8, bufmap.get("x").?, "3"));
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testing.expect(1 == bufmap.count());
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bufmap.delete("x");
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testing.expect(0 == bufmap.count());
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}
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