uuidv7 draft in zig (fixed enough to compile, but not all the way)

README.md

Repo at https://github.com/coolaj86/zig-uuidv7

• https://github.com/coolaj86/zig-uuidv7

See https://buildkite.com/blog/goodbye-integers-hello-uuids

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           unix_ts_ms                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          unix_ts_ms           |  ver  |       rand_a          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |var|                        rand_b                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            rand_b                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

build.sh

# zig 0.14.0-dev.1511+54b668f8a (2024-09-12)
# Copyright 2024 AJ ONeal <[email protected]>
# Licensed under MPL-2.0
# Repo at https://github.com/coolaj86/zig-uuidv7


#!/bin/sh

# libc targets do not need to link against external libc
#
b_libc_targets="aarch64-linux-android
aarch64-linux-gnu
aarch64-linux-musl
aarch64-macos-none
aarch64-windows-gnu
aarch64_be-linux-gnu
aarch64_be-linux-musl
arm-linux-gnu
arm-linux-gnueabi
arm-linux-gnueabihf
arm-linux-musleabi
arm-linux-musleabihf
armeb-linux-gnueabi
armeb-linux-gnueabihf
armeb-linux-musleabi
armeb-linux-musleabihf
loongarch64-linux-gnu
loongarch64-linux-musl
mips-linux-gnueabi
mips-linux-gnueabihf
mips-linux-musleabi
mips-linux-musleabihf
mips64-linux-gnuabi64
mips64-linux-gnuabin32
mips64-linux-musl
mips64el-linux-gnuabi64
mips64el-linux-gnuabin32
mips64el-linux-musl
mipsel-linux-gnueabi
mipsel-linux-gnueabihf
mipsel-linux-musleabi
mipsel-linux-musleabihf
powerpc-linux-gnueabi
powerpc-linux-gnueabihf
powerpc-linux-musleabi
powerpc-linux-musleabihf
powerpc64-linux-gnu
powerpc64-linux-musl
powerpc64le-linux-gnu
powerpc64le-linux-musl
riscv32-linux-gnu
riscv32-linux-musl
riscv64-linux-gnu
riscv64-linux-musl
thumb-linux-musleabi
thumb-linux-musleabihf
thumb-windows-gnu
thumbeb-linux-musleabi
thumbeb-linux-musleabihf
wasm32-wasi-musl
wasm32-wasi-none
x86-linux-gnu
x86-linux-musl
x86-windows-gnu
x86_64-linux-gnu
x86_64-linux-gnux32
x86_64-linux-musl
x86_64-macos-none
x86_64-windows-gnu"

# However, these libc targets were removed because they failed
#
# ERROR: wasm32-freestanding-musl
# ERROR: sparc64-linux-gnu
# ERROR: sparc-linux-gnu
# ERROR: s390x-linux-musl
# ERROR: s390x-linux-gnu
# ERROR: m68k-linux-musl
# ERROR: m68k-linux-gnu
# ERROR: csky-linux-gnueabihf
# ERROR: csky-linux-gnueabi

for b_target in ${b_libc_targets}; do
    echo >&2 "${b_target}"
    zig build-exe ./uuidv7.zig -O ReleaseSmall -target "${b_target}" -femit-bin="uuidv7-${b_target}"
done

# these non-libc targets require a libc to link against
#
# ERROR: aarch64-freebsd-gnu
# ERROR: aarch64-ios-none
# ERROR: aarch64-netbsd-gnu
# ERROR: aarch64-openbsd-gnu
# ERROR: arm-plan9-none
# ERROR: powerpc64-aix-none
# ERROR: s390x-linux-gnu
# ERROR: wasm32-freestanding-none
# ERROR: x86-freebsd-gnu
# ERROR: x86-netbsd-gnu
# ERROR: x86-openbsd-gnu
# ERROR: x86-plan9-none
# ERROR: x86_64-dragonfly-none
# ERROR: x86_64-freebsd-gnu
# ERROR: x86_64-illumos-none
# ERROR: x86_64-netbsd-gnu
# ERROR: x86_64-openbsd-gnu
# ERROR: x86_64-plan9-none
# ERROR: x86_64-solaris-none

uuidv7.zig

// zig 0.14.0-dev.1511+54b668f8a (2024-09-12)
// zig build-exe uuidv7.zig  -O ReleaseSmall -femit-bin=uuidv7
// Copyright 2024 (c) AJ ONeal
// Licensed under the MPL-2.0

const std = @import("std");
const builtin = @import("builtin");

pub fn main() !void {
    const stdout = std.io.getStdOut().writer();

    const getrandom = if (builtin.os.tag == .windows) std.os.windows.RtlGenRandom else std.posix.getrandom;

    const uuid7 = try generateUUIDv7(getrandom);
    const uuid7str = try uuidToString(uuid7);
    try stdout.print("{s}\n", .{uuid7str});
}

pub const UUID = struct {
    time_high: u32,
    time_low: u16,
    version_random1: u16,
    variant_random2: u16,
    random3: u16,
    random4: u32,
};

fn generateUUIDv7(getrandom: anytype) !UUID {
    // Get the current Unix timestamp in milliseconds
    const inow = std.time.milliTimestamp();
    const now: u64 = @intCast(inow); // we use 48 bits

    const time_low: u16 = @truncate(now);
    const time_high: u32 = @truncate(now >> 16);

    const version = (0b111 << 12); // 0b111 is the 7 in UUIDv7
    const version_mask = 0x0FFF;

    const variant = (0b10 << 14); // 0b10 is the endianness-indicating variant
    const variant_mask = 0b0011111111111111;

    var random_bytes: [10]u8 = undefined;
    try getrandom(&random_bytes);

    const version_random1: u16 = (((@as(u16, random_bytes[0]) << 8) | @as(u16, random_bytes[1])) &
        version_mask) | version;
    const variant_random2: u16 = ((((@as(u16, random_bytes[2]) << 8) | @as(u16, random_bytes[3])) &
        variant_mask)) | variant;
    const random3: u16 = (@as(u16, random_bytes[4]) << 8) | @as(u16, random_bytes[5]);
    const random4: u32 = (@as(u32, random_bytes[6]) << 24) |
        (@as(u32, random_bytes[7]) << 16) |
        (@as(u32, random_bytes[8]) << 8) |
        @as(u32, random_bytes[9]);

    return UUID{
        .time_high = time_high,
        .time_low = time_low,
        .version_random1 = version_random1,
        .variant_random2 = variant_random2,
        .random3 = random3,
        .random4 = random4,
    };
}

fn uuidToString(uuid: UUID) ![]const u8 {
    var buffer: [36]u8 = undefined;
    // time_h32-t_16-verh-varh-rand03rand04
    // 019212d3-87f4-7d25-902e-b8d39fe07f08
    return std.fmt.bufPrint(&buffer, "{x:08}-{x}-{x}-{x:04}-{x:04}{x:08}", .{ uuid.time_high, uuid.time_low, uuid.version_random1, uuid.variant_random2, uuid.random3, uuid.random4 });
}