zig/std/buf_map.zig

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const std = @import("index.zig");
const HashMap = std.HashMap;
const mem = std.mem;
const Allocator = mem.Allocator;
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const assert = std.debug.assert;
/// BufMap copies keys and values before they go into the map, and
/// frees them when they get removed.
pub const BufMap = struct {
hash_map: BufMapHashMap,
const BufMapHashMap = HashMap([]const u8, []const u8, mem.hash_slice_u8, mem.eql_slice_u8);
pub fn init(allocator: *Allocator) BufMap {
var self = BufMap{ .hash_map = BufMapHashMap.init(allocator) };
return self;
}
pub fn deinit(self: *const BufMap) void {
var it = self.hash_map.iterator();
while (true) {
const entry = it.next() ?? break;
self.free(entry.key);
self.free(entry.value);
}
self.hash_map.deinit();
}
pub fn set(self: *BufMap, key: []const u8, value: []const u8) !void {
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self.delete(key);
const key_copy = try self.copy(key);
errdefer self.free(key_copy);
const value_copy = try self.copy(value);
errdefer self.free(value_copy);
_ = try self.hash_map.put(key_copy, value_copy);
}
pub fn get(self: *const BufMap, key: []const u8) ?[]const u8 {
const entry = self.hash_map.get(key) ?? return null;
return entry.value;
}
pub fn delete(self: *BufMap, key: []const u8) void {
const entry = self.hash_map.remove(key) ?? return;
self.free(entry.key);
self.free(entry.value);
}
pub fn count(self: *const BufMap) usize {
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return self.hash_map.count();
}
pub fn iterator(self: *const BufMap) BufMapHashMap.Iterator {
return self.hash_map.iterator();
}
fn free(self: *const BufMap, value: []const u8) void {
self.hash_map.allocator.free(value);
}
fn copy(self: *const BufMap, value: []const u8) ![]const u8 {
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return mem.dupe(self.hash_map.allocator, u8, value);
}
};
test "BufMap" {
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var direct_allocator = std.heap.DirectAllocator.init();
defer direct_allocator.deinit();
var bufmap = BufMap.init(&direct_allocator.allocator);
defer bufmap.deinit();
try bufmap.set("x", "1");
assert(mem.eql(u8, ??bufmap.get("x"), "1"));
assert(1 == bufmap.count());
try bufmap.set("x", "2");
assert(mem.eql(u8, ??bufmap.get("x"), "2"));
assert(1 == bufmap.count());
try bufmap.set("x", "3");
assert(mem.eql(u8, ??bufmap.get("x"), "3"));
assert(1 == bufmap.count());
bufmap.delete("x");
assert(0 == bufmap.count());
}