StringTable

pub const StringTable = struct

File

Code

pub const StringTable = struct {
    data: std.ArrayList(u8) = .empty,
    map: std.HashMapUnmanaged(u32, void, std.hash_map.StringIndexContext, std.hash_map.default_max_load_percentage) = .empty,

    pub fn deinit(self: *StringTable, allocator: Allocator) void {
        self.data.deinit(allocator);
        self.map.deinit(allocator);
    }

    pub fn put(self: *StringTable, allocator: Allocator, value: []const u8) !u32 {
        const result = try self.map.getOrPutContextAdapted(
            allocator,
            value,
            std.hash_map.StringIndexAdapter{ .bytes = &self.data },
            .{ .bytes = &self.data },
        );
        if (result.found_existing) {
            return result.key_ptr.*;
        }

        try self.data.ensureUnusedCapacity(allocator, value.len + 1);
        const offset: u32 = @intCast(self.data.items.len);

        self.data.appendSliceAssumeCapacity(value);
        self.data.appendAssumeCapacity(0);

        result.key_ptr.* = offset;

        return offset;
    }

    pub fn get(self: StringTable, offset: u32) []const u8 {
        std.debug.assert(offset < self.data.items.len);
        return std.mem.sliceTo(@as([*:0]const u8, @ptrCast(self.data.items.ptr + offset)), 0);
    }

    pub fn getOffset(self: *StringTable, value: []const u8) ?u32 {
        return self.map.getKeyAdapted(
            value,
            std.hash_map.StringIndexAdapter{ .bytes = &self.data },
        );
    }
}