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symintern.zig (1014B)

      1 const std = @import("std");
      2 
      3 const Interner = struct {
      4     all: std.mem.Allocator,
      5     values: std.StringHashMap([]const u8),
      6 
      7     fn init(all: std.mem.Allocator) @This() {
      8         return .{ .all = all, .values = std.StringHashMap([]const u8).init(all) };
      9     }
     10 
     11     fn intern(self: *@This(), val: []const u8) ![]const u8 {
     12         if (self.values.get(val)) |found| {
     13             return found;
     14         } else {
     15             const copied = try self.all.dupe(u8, val);
     16             try self.values.put(copied, copied);
     17 
     18             return copied;
     19         }
     20     }
     21 
     22     fn deinit(self: *@This()) void {
     23         var iter = self.values.valueIterator();
     24 
     25         while (iter.next()) |val| {
     26             self.all.free(val.*);
     27         }
     28 
     29         self.values.deinit();
     30     }
     31 };
     32 
     33 var interner: Interner = undefined;
     34 
     35 pub fn init(all: std.mem.Allocator) void {
     36     interner = Interner.init(all);
     37 }
     38 
     39 pub fn deinit() void {
     40     interner.deinit();
     41 }
     42 
     43 pub fn intern(val: []const u8) ![]const u8 {
     44     return interner.intern(val);
     45 }