struct Params [src]

Fields

properties: Properties
dict_size: u32
unpacked_size: ?u64
Members

readHeader (Function)
Source

  pub const Params = struct {
    properties: Properties,
    dict_size: u32,
    unpacked_size: ?u64,

    pub fn readHeader(reader: *Reader, options: Options) !Params {
        var props = try reader.takeByte();
        if (props >= 225) return error.CorruptInput;

        const lc: u4 = @intCast(props % 9);
        props /= 9;
        const lp: u3 = @intCast(props % 5);
        props /= 5;
        const pb: u3 = @intCast(props);

        const dict_size_provided = try reader.takeInt(u32, .little);
        const dict_size = @max(0x1000, dict_size_provided);

        const unpacked_size = switch (options.unpacked_size) {
            .read_from_header => blk: {
                const unpacked_size_provided = try reader.takeInt(u64, .little);
                const marker_mandatory = unpacked_size_provided == 0xFFFF_FFFF_FFFF_FFFF;
                break :blk if (marker_mandatory) null else unpacked_size_provided;
            },
            .read_header_but_use_provided => |x| blk: {
                _ = try reader.takeInt(u64, .little);
                break :blk x;
            },
            .use_provided => |x| x,
        };

        return .{
            .properties = .{ .lc = lc, .lp = lp, .pb = pb },
            .dict_size = dict_size,
            .unpacked_size = unpacked_size,
        };
    }
}  