pub fn format(u: *const Unresolved, w: *Io.Writer) Io.Writer.Error!void {
const bytes = &u.bytes;
if (std.mem.eql(u8, bytes[0..12], &[_]u8{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xff, 0xff })) {
try w.print("::ffff:{d}.{d}.{d}.{d}", .{ bytes[12], bytes[13], bytes[14], bytes[15] });
} else {
const parts: [8]u16 = .{
std.mem.readInt(u16, bytes[0..2], .big),
std.mem.readInt(u16, bytes[2..4], .big),
std.mem.readInt(u16, bytes[4..6], .big),
std.mem.readInt(u16, bytes[6..8], .big),
std.mem.readInt(u16, bytes[8..10], .big),
std.mem.readInt(u16, bytes[10..12], .big),
std.mem.readInt(u16, bytes[12..14], .big),
std.mem.readInt(u16, bytes[14..16], .big),
};
// Find the longest zero run
var longest_start: usize = 8;
var longest_len: usize = 0;
var current_start: usize = 0;
var current_len: usize = 0;
for (parts, 0..) |part, i| {
if (part == 0) {
if (current_len == 0) {
current_start = i;
}
current_len += 1;
if (current_len > longest_len) {
longest_start = current_start;
longest_len = current_len;
}
} else {
current_len = 0;
}
}
// Only compress if the longest zero run is 2 or more
if (longest_len < 2) {
longest_start = 8;
longest_len = 0;
}
var i: usize = 0;
while (parts.len - i != 0) : (i += 1) {
if (i == longest_start) {
// Emit "::" for the longest zero run
try w.writeAll(if (i == 0) "::" else ":");
i += longest_len - 1; // Skip the compressed range
continue;
}
try w.print("{x}", .{parts[i]});
if (i != parts.len - 1) {
try w.writeAll(":");
}
}
}
if (u.interface_name) |n| try w.print("%{s}", .{n});
}
