Zig

Generating Repeatable Random Data for Testing/Debugging

See more PRNG Examples

Demonstrates how to use the Fortuna PRNG to generate random-looking but repeatable non-random data for the purpose of testing and debugging. Zig

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

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    const fortuna = try chilkat.Prng.init();
    defer fortuna.deinit();

    // Normally an application would seed the PRNG with entropy from
    // some real random source.  However, sometimes we want the same
    // random sequence of bytes for testing and debugging purposes.
    // This a reason why GetEntropy and AddEntropy are two different methods.
    // An application could omit the call to GetEntropy, and instead pass
    // non-random data to AddEntropy. For example:

    // Seed the PRNG with non-entropy, so we get a repeatable sequence.
    // Note: AddEntropy can be called any number of times.
    try fortuna.addEntropy("01020304", "hex");
    try fortuna.addEntropy("hello world", "ascii");

    // Generate some random data:
    var str_rand_hex: [:0]const u8 = try fortuna.genRandom(alloc, 16, "hex");
    var str_rand_base64: [:0]const u8 = try fortuna.genRandom(alloc, 22, "base64");
    var str_rand_base58: [:0]const u8 = try fortuna.genRandom(alloc, 32, "base58");

    std.debug.print("hex random bytes: {s}\n", .{str_rand_hex});
    std.debug.print("base64 random bytes: {s}\n", .{str_rand_base64});
    std.debug.print("base58 random bytes: {s}\n", .{str_rand_base58});

    // Try it again with a different object to verify that the same results are obtained:
    const fortuna2 = try chilkat.Prng.init();
    defer fortuna2.deinit();

    try fortuna2.addEntropy("01020304", "hex");
    try fortuna2.addEntropy("hello world", "ascii");

    str_rand_hex = try fortuna2.genRandom(alloc, 16, "hex");
    str_rand_base64 = try fortuna2.genRandom(alloc, 22, "base64");
    str_rand_base58 = try fortuna2.genRandom(alloc, 32, "base58");

    std.debug.print("hex random bytes: {s}\n", .{str_rand_hex});
    std.debug.print("base64 random bytes: {s}\n", .{str_rand_base64});
    std.debug.print("base58 random bytes: {s}\n", .{str_rand_base58});
}