UUIDv4 in swift

Implementation

import Foundation

if let f = FileHandle(forReadingAtPath: "/dev/random") {
    if let read = try f.read(upToCount: 16) {
        if read.count != 16 {
            print("Could not read 16 bytes")
            exit(1)
        }
        var buf: [UInt8] = Array(read)

        // Set bit 6 to 0
        buf[8] &= ~(1 << 6)
        // Set bit 7 to 1
        buf[8] |= 1 << 7

        // Set version
        buf[6] &= ~(1 << 4)
        buf[6] &= ~(1 << 5)
        buf[6] |= 1 << 6
        buf[6] &= ~(1 << 7)

        print(String(format: "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
	             buf[0],
	             buf[1],
	             buf[2],
	             buf[3],
	             // -
	             buf[4],
	             buf[5],
	             // - 
	             buf[6],
	             buf[7],
	             // -
	             buf[8],
	             buf[9],
	             // -
	             buf[10],
	             buf[11],
	             buf[12],
	             buf[13],
	             buf[14],
	             buf[15]))
    } else {
        print("Could not read any bytes")
        exit(1)
    }
} else {
    print("Could not open /dev/random")
    exit(1)
}

Build and run

These steps are linux only.

$ swiftc main.swift

$ ./main $myProgram

All implementations

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