Function format [src]

To allow std.fmt.format to work with this type. If the absolute value of integer is greater than or equal to pow(2, 64 * @sizeOf(usize) * 8), this function will fail to print the string, printing "(BigInt)" instead of a number. This is because the rendering algorithm requires reversing a string, which requires O(N) memory. See toString and toStringAlloc for a way to print big integers without failure.

Prototype

pub fn format( self: Const, comptime fmt: []const u8, options: std.fmt.FormatOptions, out_stream: anytype, ) !void

Parameters

self: Constfmt: []const u8options: std.fmt.FormatOptions

Source

  pub fn format(
    self: Const,
    comptime fmt: []const u8,
    options: std.fmt.FormatOptions,
    out_stream: anytype,
) !void {
    _ = options;
    comptime var base = 10;
    comptime var case: std.fmt.Case = .lower;

    if (fmt.len == 0 or comptime mem.eql(u8, fmt, "d")) {
        base = 10;
        case = .lower;
    } else if (comptime mem.eql(u8, fmt, "b")) {
        base = 2;
        case = .lower;
    } else if (comptime mem.eql(u8, fmt, "x")) {
        base = 16;
        case = .lower;
    } else if (comptime mem.eql(u8, fmt, "X")) {
        base = 16;
        case = .upper;
    } else {
        std.fmt.invalidFmtError(fmt, self);
    }

    const available_len = 64;
    if (self.limbs.len > available_len)
        return out_stream.writeAll("(BigInt)");

    var limbs: [calcToStringLimbsBufferLen(available_len, base)]Limb = undefined;

    const biggest: Const = .{
        .limbs = &([1]Limb{comptime math.maxInt(Limb)} ** available_len),
        .positive = false,
    };
    var buf: [biggest.sizeInBaseUpperBound(base)]u8 = undefined;
    const len = self.toString(&buf, base, case, &limbs);
    return out_stream.writeAll(buf[0..len]);
}  