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// SPDX-License-Identifier: MIT
// Copyright (c) 2015-2021 Zig Contributors
// This file is part of [zig](https://ziglang.org/), which is MIT licensed.
// The MIT license requires this copyright notice to be included in all copies
// and substantial portions of the software.
const std = @import("std.zig");
const StringHashMap = std.StringHashMap;
const mem = @import("mem.zig");
const Allocator = mem.Allocator;
const testing = std.testing;
/// A BufSet is a set of strings. The BufSet duplicates
/// strings internally, and never takes ownership of strings
/// which are passed to it.
pub const BufSet = struct {
hash_map: BufSetHashMap,
const BufSetHashMap = StringHashMap(void);
pub const Iterator = BufSetHashMap.KeyIterator;
/// Create a BufSet using an allocator. The allocator will
/// be used internally for both backing allocations and
/// string duplication.
pub fn init(a: *Allocator) BufSet {
var self = BufSet{ .hash_map = BufSetHashMap.init(a) };
return self;
}
/// Free a BufSet along with all stored keys.
pub fn deinit(self: *BufSet) void {
var it = self.hash_map.keyIterator();
while (it.next()) |key_ptr| {
self.free(key_ptr.*);
}
self.hash_map.deinit();
self.* = undefined;
}
/// Insert an item into the BufSet. The item will be
/// copied, so the caller may delete or reuse the
/// passed string immediately.
pub fn insert(self: *BufSet, value: []const u8) !void {
const gop = try self.hash_map.getOrPut(value);
if (!gop.found_existing) {
gop.key_ptr.* = self.copy(value) catch |err| {
_ = self.hash_map.remove(value);
return err;
};
}
}
/// Check if the set contains an item matching the passed string
pub fn contains(self: BufSet, value: []const u8) bool {
return self.hash_map.contains(value);
}
/// Remove an item from the set.
pub fn remove(self: *BufSet, value: []const u8) void {
const kv = self.hash_map.fetchRemove(value) orelse return;
self.free(kv.key);
}
/// Returns the number of items stored in the set
pub fn count(self: *const BufSet) usize {
return self.hash_map.count();
}
/// Returns an iterator over the items stored in the set.
/// Iteration order is arbitrary.
pub fn iterator(self: *const BufSet) Iterator {
return self.hash_map.keyIterator();
}
/// Get the allocator used by this set
pub fn allocator(self: *const BufSet) *Allocator {
return self.hash_map.allocator;
}
fn free(self: *const BufSet, value: []const u8) void {
self.hash_map.allocator.free(value);
}
fn copy(self: *const BufSet, value: []const u8) ![]const u8 {
const result = try self.hash_map.allocator.alloc(u8, value.len);
mem.copy(u8, result, value);
return result;
}
};
test "BufSet" {
var bufset = BufSet.init(std.testing.allocator);
defer bufset.deinit();
try bufset.insert("x");
try testing.expect(bufset.count() == 1);
bufset.remove("x");
try testing.expect(bufset.count() == 0);
try bufset.insert("x");
try bufset.insert("y");
try bufset.insert("z");
}
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