mirror of
https://github.com/ziglang/zig.git
synced 2024-11-27 15:42:49 +00:00
bf3ac66150
* Implements #3768. This is a sweeping breaking change that requires many (trivial) edits to Zig source code. Array values no longer coerced to slices; however one may use `&` to obtain a reference to an array value, which may then be coerced to a slice. * Adds `IrInstruction::dump`, for debugging purposes. It's useful to call to inspect the instruction when debugging Zig IR. * Fixes bugs with result location semantics. See the new behavior test cases, and compile error test cases. * Fixes bugs with `@typeInfo` not properly resolving const values. * Behavior tests are passing but std lib tests are not yet. There is more work to do before merging this branch.
1106 lines
33 KiB
Zig
1106 lines
33 KiB
Zig
// The engines provided here should be initialized from an external source. For now, randomBytes
|
|
// from the crypto package is the most suitable. Be sure to use a CSPRNG when required, otherwise using
|
|
// a normal PRNG will be faster and use substantially less stack space.
|
|
//
|
|
// ```
|
|
// var buf: [8]u8 = undefined;
|
|
// try std.crypto.randomBytes(buf[0..]);
|
|
// const seed = mem.readIntSliceLittle(u64, buf[0..8]);
|
|
//
|
|
// var r = DefaultPrng.init(seed);
|
|
//
|
|
// const s = r.random.int(u64);
|
|
// ```
|
|
//
|
|
// TODO(tiehuis): Benchmark these against other reference implementations.
|
|
|
|
const std = @import("std.zig");
|
|
const builtin = @import("builtin");
|
|
const assert = std.debug.assert;
|
|
const expect = std.testing.expect;
|
|
const expectEqual = std.testing.expectEqual;
|
|
const mem = std.mem;
|
|
const math = std.math;
|
|
const ziggurat = @import("rand/ziggurat.zig");
|
|
const maxInt = std.math.maxInt;
|
|
|
|
// When you need fast unbiased random numbers
|
|
pub const DefaultPrng = Xoroshiro128;
|
|
|
|
// When you need cryptographically secure random numbers
|
|
pub const DefaultCsprng = Isaac64;
|
|
|
|
pub const Random = struct {
|
|
fillFn: fn (r: *Random, buf: []u8) void,
|
|
|
|
/// Read random bytes into the specified buffer until full.
|
|
pub fn bytes(r: *Random, buf: []u8) void {
|
|
r.fillFn(r, buf);
|
|
}
|
|
|
|
pub fn boolean(r: *Random) bool {
|
|
return r.int(u1) != 0;
|
|
}
|
|
|
|
/// Returns a random int `i` such that `0 <= i <= maxInt(T)`.
|
|
/// `i` is evenly distributed.
|
|
pub fn int(r: *Random, comptime T: type) T {
|
|
const UnsignedT = @IntType(false, T.bit_count);
|
|
const ByteAlignedT = @IntType(false, @divTrunc(T.bit_count + 7, 8) * 8);
|
|
|
|
var rand_bytes: [@sizeOf(ByteAlignedT)]u8 = undefined;
|
|
r.bytes(rand_bytes[0..]);
|
|
|
|
// use LE instead of native endian for better portability maybe?
|
|
// TODO: endian portability is pointless if the underlying prng isn't endian portable.
|
|
// TODO: document the endian portability of this library.
|
|
const byte_aligned_result = mem.readIntSliceLittle(ByteAlignedT, &rand_bytes);
|
|
const unsigned_result = @truncate(UnsignedT, byte_aligned_result);
|
|
return @bitCast(T, unsigned_result);
|
|
}
|
|
|
|
/// Constant-time implementation off ::uintLessThan.
|
|
/// The results of this function may be biased.
|
|
pub fn uintLessThanBiased(r: *Random, comptime T: type, less_than: T) T {
|
|
comptime assert(T.is_signed == false);
|
|
comptime assert(T.bit_count <= 64); // TODO: workaround: LLVM ERROR: Unsupported library call operation!
|
|
assert(0 < less_than);
|
|
if (T.bit_count <= 32) {
|
|
return @intCast(T, limitRangeBiased(u32, r.int(u32), less_than));
|
|
} else {
|
|
return @intCast(T, limitRangeBiased(u64, r.int(u64), less_than));
|
|
}
|
|
}
|
|
|
|
/// Returns an evenly distributed random unsigned integer `0 <= i < less_than`.
|
|
/// This function assumes that the underlying ::fillFn produces evenly distributed values.
|
|
/// Within this assumption, the runtime of this function is exponentially distributed.
|
|
/// If ::fillFn were backed by a true random generator,
|
|
/// the runtime of this function would technically be unbounded.
|
|
/// However, if ::fillFn is backed by any evenly distributed pseudo random number generator,
|
|
/// this function is guaranteed to return.
|
|
/// If you need deterministic runtime bounds, use `::uintLessThanBiased`.
|
|
pub fn uintLessThan(r: *Random, comptime T: type, less_than: T) T {
|
|
comptime assert(T.is_signed == false);
|
|
comptime assert(T.bit_count <= 64); // TODO: workaround: LLVM ERROR: Unsupported library call operation!
|
|
assert(0 < less_than);
|
|
// Small is typically u32
|
|
const Small = @IntType(false, @divTrunc(T.bit_count + 31, 32) * 32);
|
|
// Large is typically u64
|
|
const Large = @IntType(false, Small.bit_count * 2);
|
|
|
|
// adapted from:
|
|
// http://www.pcg-random.org/posts/bounded-rands.html
|
|
// "Lemire's (with an extra tweak from me)"
|
|
var x: Small = r.int(Small);
|
|
var m: Large = @as(Large, x) * @as(Large, less_than);
|
|
var l: Small = @truncate(Small, m);
|
|
if (l < less_than) {
|
|
// TODO: workaround for https://github.com/ziglang/zig/issues/1770
|
|
// should be:
|
|
// var t: Small = -%less_than;
|
|
var t: Small = @bitCast(Small, -%@bitCast(@IntType(true, Small.bit_count), @as(Small, less_than)));
|
|
|
|
if (t >= less_than) {
|
|
t -= less_than;
|
|
if (t >= less_than) {
|
|
t %= less_than;
|
|
}
|
|
}
|
|
while (l < t) {
|
|
x = r.int(Small);
|
|
m = @as(Large, x) * @as(Large, less_than);
|
|
l = @truncate(Small, m);
|
|
}
|
|
}
|
|
return @intCast(T, m >> Small.bit_count);
|
|
}
|
|
|
|
/// Constant-time implementation off ::uintAtMost.
|
|
/// The results of this function may be biased.
|
|
pub fn uintAtMostBiased(r: *Random, comptime T: type, at_most: T) T {
|
|
assert(T.is_signed == false);
|
|
if (at_most == maxInt(T)) {
|
|
// have the full range
|
|
return r.int(T);
|
|
}
|
|
return r.uintLessThanBiased(T, at_most + 1);
|
|
}
|
|
|
|
/// Returns an evenly distributed random unsigned integer `0 <= i <= at_most`.
|
|
/// See ::uintLessThan, which this function uses in most cases,
|
|
/// for commentary on the runtime of this function.
|
|
pub fn uintAtMost(r: *Random, comptime T: type, at_most: T) T {
|
|
assert(T.is_signed == false);
|
|
if (at_most == maxInt(T)) {
|
|
// have the full range
|
|
return r.int(T);
|
|
}
|
|
return r.uintLessThan(T, at_most + 1);
|
|
}
|
|
|
|
/// Constant-time implementation off ::intRangeLessThan.
|
|
/// The results of this function may be biased.
|
|
pub fn intRangeLessThanBiased(r: *Random, comptime T: type, at_least: T, less_than: T) T {
|
|
assert(at_least < less_than);
|
|
if (T.is_signed) {
|
|
// Two's complement makes this math pretty easy.
|
|
const UnsignedT = @IntType(false, T.bit_count);
|
|
const lo = @bitCast(UnsignedT, at_least);
|
|
const hi = @bitCast(UnsignedT, less_than);
|
|
const result = lo +% r.uintLessThanBiased(UnsignedT, hi -% lo);
|
|
return @bitCast(T, result);
|
|
} else {
|
|
// The signed implementation would work fine, but we can use stricter arithmetic operators here.
|
|
return at_least + r.uintLessThanBiased(T, less_than - at_least);
|
|
}
|
|
}
|
|
|
|
/// Returns an evenly distributed random integer `at_least <= i < less_than`.
|
|
/// See ::uintLessThan, which this function uses in most cases,
|
|
/// for commentary on the runtime of this function.
|
|
pub fn intRangeLessThan(r: *Random, comptime T: type, at_least: T, less_than: T) T {
|
|
assert(at_least < less_than);
|
|
if (T.is_signed) {
|
|
// Two's complement makes this math pretty easy.
|
|
const UnsignedT = @IntType(false, T.bit_count);
|
|
const lo = @bitCast(UnsignedT, at_least);
|
|
const hi = @bitCast(UnsignedT, less_than);
|
|
const result = lo +% r.uintLessThan(UnsignedT, hi -% lo);
|
|
return @bitCast(T, result);
|
|
} else {
|
|
// The signed implementation would work fine, but we can use stricter arithmetic operators here.
|
|
return at_least + r.uintLessThan(T, less_than - at_least);
|
|
}
|
|
}
|
|
|
|
/// Constant-time implementation off ::intRangeAtMostBiased.
|
|
/// The results of this function may be biased.
|
|
pub fn intRangeAtMostBiased(r: *Random, comptime T: type, at_least: T, at_most: T) T {
|
|
assert(at_least <= at_most);
|
|
if (T.is_signed) {
|
|
// Two's complement makes this math pretty easy.
|
|
const UnsignedT = @IntType(false, T.bit_count);
|
|
const lo = @bitCast(UnsignedT, at_least);
|
|
const hi = @bitCast(UnsignedT, at_most);
|
|
const result = lo +% r.uintAtMostBiased(UnsignedT, hi -% lo);
|
|
return @bitCast(T, result);
|
|
} else {
|
|
// The signed implementation would work fine, but we can use stricter arithmetic operators here.
|
|
return at_least + r.uintAtMostBiased(T, at_most - at_least);
|
|
}
|
|
}
|
|
|
|
/// Returns an evenly distributed random integer `at_least <= i <= at_most`.
|
|
/// See ::uintLessThan, which this function uses in most cases,
|
|
/// for commentary on the runtime of this function.
|
|
pub fn intRangeAtMost(r: *Random, comptime T: type, at_least: T, at_most: T) T {
|
|
assert(at_least <= at_most);
|
|
if (T.is_signed) {
|
|
// Two's complement makes this math pretty easy.
|
|
const UnsignedT = @IntType(false, T.bit_count);
|
|
const lo = @bitCast(UnsignedT, at_least);
|
|
const hi = @bitCast(UnsignedT, at_most);
|
|
const result = lo +% r.uintAtMost(UnsignedT, hi -% lo);
|
|
return @bitCast(T, result);
|
|
} else {
|
|
// The signed implementation would work fine, but we can use stricter arithmetic operators here.
|
|
return at_least + r.uintAtMost(T, at_most - at_least);
|
|
}
|
|
}
|
|
|
|
/// TODO: deprecated. use ::boolean or ::int instead.
|
|
pub fn scalar(r: *Random, comptime T: type) T {
|
|
return if (T == bool) r.boolean() else r.int(T);
|
|
}
|
|
|
|
/// TODO: deprecated. renamed to ::intRangeLessThan
|
|
pub fn range(r: *Random, comptime T: type, start: T, end: T) T {
|
|
return r.intRangeLessThan(T, start, end);
|
|
}
|
|
|
|
/// Return a floating point value evenly distributed in the range [0, 1).
|
|
pub fn float(r: *Random, comptime T: type) T {
|
|
// Generate a uniform value between [1, 2) and scale down to [0, 1).
|
|
// Note: The lowest mantissa bit is always set to 0 so we only use half the available range.
|
|
switch (T) {
|
|
f32 => {
|
|
const s = r.int(u32);
|
|
const repr = (0x7f << 23) | (s >> 9);
|
|
return @bitCast(f32, repr) - 1.0;
|
|
},
|
|
f64 => {
|
|
const s = r.int(u64);
|
|
const repr = (0x3ff << 52) | (s >> 12);
|
|
return @bitCast(f64, repr) - 1.0;
|
|
},
|
|
else => @compileError("unknown floating point type"),
|
|
}
|
|
}
|
|
|
|
/// Return a floating point value normally distributed with mean = 0, stddev = 1.
|
|
///
|
|
/// To use different parameters, use: floatNorm(...) * desiredStddev + desiredMean.
|
|
pub fn floatNorm(r: *Random, comptime T: type) T {
|
|
const value = ziggurat.next_f64(r, ziggurat.NormDist);
|
|
switch (T) {
|
|
f32 => return @floatCast(f32, value),
|
|
f64 => return value,
|
|
else => @compileError("unknown floating point type"),
|
|
}
|
|
}
|
|
|
|
/// Return an exponentially distributed float with a rate parameter of 1.
|
|
///
|
|
/// To use a different rate parameter, use: floatExp(...) / desiredRate.
|
|
pub fn floatExp(r: *Random, comptime T: type) T {
|
|
const value = ziggurat.next_f64(r, ziggurat.ExpDist);
|
|
switch (T) {
|
|
f32 => return @floatCast(f32, value),
|
|
f64 => return value,
|
|
else => @compileError("unknown floating point type"),
|
|
}
|
|
}
|
|
|
|
/// Shuffle a slice into a random order.
|
|
pub fn shuffle(r: *Random, comptime T: type, buf: []T) void {
|
|
if (buf.len < 2) {
|
|
return;
|
|
}
|
|
|
|
var i: usize = 0;
|
|
while (i < buf.len - 1) : (i += 1) {
|
|
const j = r.intRangeLessThan(usize, i, buf.len);
|
|
mem.swap(T, &buf[i], &buf[j]);
|
|
}
|
|
}
|
|
};
|
|
|
|
/// Convert a random integer 0 <= random_int <= maxValue(T),
|
|
/// into an integer 0 <= result < less_than.
|
|
/// This function introduces a minor bias.
|
|
pub fn limitRangeBiased(comptime T: type, random_int: T, less_than: T) T {
|
|
comptime assert(T.is_signed == false);
|
|
const T2 = @IntType(false, T.bit_count * 2);
|
|
|
|
// adapted from:
|
|
// http://www.pcg-random.org/posts/bounded-rands.html
|
|
// "Integer Multiplication (Biased)"
|
|
var m: T2 = @as(T2, random_int) * @as(T2, less_than);
|
|
return @intCast(T, m >> T.bit_count);
|
|
}
|
|
|
|
const SequentialPrng = struct {
|
|
const Self = @This();
|
|
random: Random,
|
|
next_value: u8,
|
|
|
|
pub fn init() Self {
|
|
return Self{
|
|
.random = Random{ .fillFn = fill },
|
|
.next_value = 0,
|
|
};
|
|
}
|
|
|
|
fn fill(r: *Random, buf: []u8) void {
|
|
const self = @fieldParentPtr(Self, "random", r);
|
|
for (buf) |*b| {
|
|
b.* = self.next_value;
|
|
}
|
|
self.next_value +%= 1;
|
|
}
|
|
};
|
|
|
|
test "Random int" {
|
|
testRandomInt();
|
|
comptime testRandomInt();
|
|
}
|
|
fn testRandomInt() void {
|
|
var r = SequentialPrng.init();
|
|
|
|
expect(r.random.int(u0) == 0);
|
|
|
|
r.next_value = 0;
|
|
expect(r.random.int(u1) == 0);
|
|
expect(r.random.int(u1) == 1);
|
|
expect(r.random.int(u2) == 2);
|
|
expect(r.random.int(u2) == 3);
|
|
expect(r.random.int(u2) == 0);
|
|
|
|
r.next_value = 0xff;
|
|
expect(r.random.int(u8) == 0xff);
|
|
r.next_value = 0x11;
|
|
expect(r.random.int(u8) == 0x11);
|
|
|
|
r.next_value = 0xff;
|
|
expect(r.random.int(u32) == 0xffffffff);
|
|
r.next_value = 0x11;
|
|
expect(r.random.int(u32) == 0x11111111);
|
|
|
|
r.next_value = 0xff;
|
|
expect(r.random.int(i32) == -1);
|
|
r.next_value = 0x11;
|
|
expect(r.random.int(i32) == 0x11111111);
|
|
|
|
r.next_value = 0xff;
|
|
expect(r.random.int(i8) == -1);
|
|
r.next_value = 0x11;
|
|
expect(r.random.int(i8) == 0x11);
|
|
|
|
r.next_value = 0xff;
|
|
expect(r.random.int(u33) == 0x1ffffffff);
|
|
r.next_value = 0xff;
|
|
expect(r.random.int(i1) == -1);
|
|
r.next_value = 0xff;
|
|
expect(r.random.int(i2) == -1);
|
|
r.next_value = 0xff;
|
|
expect(r.random.int(i33) == -1);
|
|
}
|
|
|
|
test "Random boolean" {
|
|
testRandomBoolean();
|
|
comptime testRandomBoolean();
|
|
}
|
|
fn testRandomBoolean() void {
|
|
var r = SequentialPrng.init();
|
|
expect(r.random.boolean() == false);
|
|
expect(r.random.boolean() == true);
|
|
expect(r.random.boolean() == false);
|
|
expect(r.random.boolean() == true);
|
|
}
|
|
|
|
test "Random intLessThan" {
|
|
@setEvalBranchQuota(10000);
|
|
testRandomIntLessThan();
|
|
comptime testRandomIntLessThan();
|
|
}
|
|
fn testRandomIntLessThan() void {
|
|
var r = SequentialPrng.init();
|
|
r.next_value = 0xff;
|
|
expect(r.random.uintLessThan(u8, 4) == 3);
|
|
expect(r.next_value == 0);
|
|
expect(r.random.uintLessThan(u8, 4) == 0);
|
|
expect(r.next_value == 1);
|
|
|
|
r.next_value = 0;
|
|
expect(r.random.uintLessThan(u64, 32) == 0);
|
|
|
|
// trigger the bias rejection code path
|
|
r.next_value = 0;
|
|
expect(r.random.uintLessThan(u8, 3) == 0);
|
|
// verify we incremented twice
|
|
expect(r.next_value == 2);
|
|
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeLessThan(u8, 0, 0x80) == 0x7f);
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeLessThan(u8, 0x7f, 0xff) == 0xfe);
|
|
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeLessThan(i8, 0, 0x40) == 0x3f);
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeLessThan(i8, -0x40, 0x40) == 0x3f);
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeLessThan(i8, -0x80, 0) == -1);
|
|
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeLessThan(i3, -4, 0) == -1);
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeLessThan(i3, -2, 2) == 1);
|
|
}
|
|
|
|
test "Random intAtMost" {
|
|
@setEvalBranchQuota(10000);
|
|
testRandomIntAtMost();
|
|
comptime testRandomIntAtMost();
|
|
}
|
|
fn testRandomIntAtMost() void {
|
|
var r = SequentialPrng.init();
|
|
r.next_value = 0xff;
|
|
expect(r.random.uintAtMost(u8, 3) == 3);
|
|
expect(r.next_value == 0);
|
|
expect(r.random.uintAtMost(u8, 3) == 0);
|
|
|
|
// trigger the bias rejection code path
|
|
r.next_value = 0;
|
|
expect(r.random.uintAtMost(u8, 2) == 0);
|
|
// verify we incremented twice
|
|
expect(r.next_value == 2);
|
|
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeAtMost(u8, 0, 0x7f) == 0x7f);
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeAtMost(u8, 0x7f, 0xfe) == 0xfe);
|
|
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeAtMost(i8, 0, 0x3f) == 0x3f);
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeAtMost(i8, -0x40, 0x3f) == 0x3f);
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeAtMost(i8, -0x80, -1) == -1);
|
|
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeAtMost(i3, -4, -1) == -1);
|
|
r.next_value = 0xff;
|
|
expect(r.random.intRangeAtMost(i3, -2, 1) == 1);
|
|
|
|
expect(r.random.uintAtMost(u0, 0) == 0);
|
|
}
|
|
|
|
test "Random Biased" {
|
|
var r = DefaultPrng.init(0);
|
|
// Not thoroughly checking the logic here.
|
|
// Just want to execute all the paths with different types.
|
|
|
|
expect(r.random.uintLessThanBiased(u1, 1) == 0);
|
|
expect(r.random.uintLessThanBiased(u32, 10) < 10);
|
|
expect(r.random.uintLessThanBiased(u64, 20) < 20);
|
|
|
|
expect(r.random.uintAtMostBiased(u0, 0) == 0);
|
|
expect(r.random.uintAtMostBiased(u1, 0) <= 0);
|
|
expect(r.random.uintAtMostBiased(u32, 10) <= 10);
|
|
expect(r.random.uintAtMostBiased(u64, 20) <= 20);
|
|
|
|
expect(r.random.intRangeLessThanBiased(u1, 0, 1) == 0);
|
|
expect(r.random.intRangeLessThanBiased(i1, -1, 0) == -1);
|
|
expect(r.random.intRangeLessThanBiased(u32, 10, 20) >= 10);
|
|
expect(r.random.intRangeLessThanBiased(i32, 10, 20) >= 10);
|
|
expect(r.random.intRangeLessThanBiased(u64, 20, 40) >= 20);
|
|
expect(r.random.intRangeLessThanBiased(i64, 20, 40) >= 20);
|
|
|
|
// uncomment for broken module error:
|
|
//expect(r.random.intRangeAtMostBiased(u0, 0, 0) == 0);
|
|
expect(r.random.intRangeAtMostBiased(u1, 0, 1) >= 0);
|
|
expect(r.random.intRangeAtMostBiased(i1, -1, 0) >= -1);
|
|
expect(r.random.intRangeAtMostBiased(u32, 10, 20) >= 10);
|
|
expect(r.random.intRangeAtMostBiased(i32, 10, 20) >= 10);
|
|
expect(r.random.intRangeAtMostBiased(u64, 20, 40) >= 20);
|
|
expect(r.random.intRangeAtMostBiased(i64, 20, 40) >= 20);
|
|
}
|
|
|
|
// Generator to extend 64-bit seed values into longer sequences.
|
|
//
|
|
// The number of cycles is thus limited to 64-bits regardless of the engine, but this
|
|
// is still plenty for practical purposes.
|
|
const SplitMix64 = struct {
|
|
s: u64,
|
|
|
|
pub fn init(seed: u64) SplitMix64 {
|
|
return SplitMix64{ .s = seed };
|
|
}
|
|
|
|
pub fn next(self: *SplitMix64) u64 {
|
|
self.s +%= 0x9e3779b97f4a7c15;
|
|
|
|
var z = self.s;
|
|
z = (z ^ (z >> 30)) *% 0xbf58476d1ce4e5b9;
|
|
z = (z ^ (z >> 27)) *% 0x94d049bb133111eb;
|
|
return z ^ (z >> 31);
|
|
}
|
|
};
|
|
|
|
test "splitmix64 sequence" {
|
|
var r = SplitMix64.init(0xaeecf86f7878dd75);
|
|
|
|
const seq = [_]u64{
|
|
0x5dbd39db0178eb44,
|
|
0xa9900fb66b397da3,
|
|
0x5c1a28b1aeebcf5c,
|
|
0x64a963238f776912,
|
|
0xc6d4177b21d1c0ab,
|
|
0xb2cbdbdb5ea35394,
|
|
};
|
|
|
|
for (seq) |s| {
|
|
expect(s == r.next());
|
|
}
|
|
}
|
|
|
|
// PCG32 - http://www.pcg-random.org/
|
|
//
|
|
// PRNG
|
|
pub const Pcg = struct {
|
|
const default_multiplier = 6364136223846793005;
|
|
|
|
random: Random,
|
|
|
|
s: u64,
|
|
i: u64,
|
|
|
|
pub fn init(init_s: u64) Pcg {
|
|
var pcg = Pcg{
|
|
.random = Random{ .fillFn = fill },
|
|
.s = undefined,
|
|
.i = undefined,
|
|
};
|
|
|
|
pcg.seed(init_s);
|
|
return pcg;
|
|
}
|
|
|
|
fn next(self: *Pcg) u32 {
|
|
const l = self.s;
|
|
self.s = l *% default_multiplier +% (self.i | 1);
|
|
|
|
const xor_s = @truncate(u32, ((l >> 18) ^ l) >> 27);
|
|
const rot = @intCast(u32, l >> 59);
|
|
|
|
return (xor_s >> @intCast(u5, rot)) | (xor_s << @intCast(u5, (0 -% rot) & 31));
|
|
}
|
|
|
|
fn seed(self: *Pcg, init_s: u64) void {
|
|
// Pcg requires 128-bits of seed.
|
|
var gen = SplitMix64.init(init_s);
|
|
self.seedTwo(gen.next(), gen.next());
|
|
}
|
|
|
|
fn seedTwo(self: *Pcg, init_s: u64, init_i: u64) void {
|
|
self.s = 0;
|
|
self.i = (init_s << 1) | 1;
|
|
self.s = self.s *% default_multiplier +% self.i;
|
|
self.s +%= init_i;
|
|
self.s = self.s *% default_multiplier +% self.i;
|
|
}
|
|
|
|
fn fill(r: *Random, buf: []u8) void {
|
|
const self = @fieldParentPtr(Pcg, "random", r);
|
|
|
|
var i: usize = 0;
|
|
const aligned_len = buf.len - (buf.len & 7);
|
|
|
|
// Complete 4 byte segments.
|
|
while (i < aligned_len) : (i += 4) {
|
|
var n = self.next();
|
|
comptime var j: usize = 0;
|
|
inline while (j < 4) : (j += 1) {
|
|
buf[i + j] = @truncate(u8, n);
|
|
n >>= 8;
|
|
}
|
|
}
|
|
|
|
// Remaining. (cuts the stream)
|
|
if (i != buf.len) {
|
|
var n = self.next();
|
|
while (i < buf.len) : (i += 1) {
|
|
buf[i] = @truncate(u8, n);
|
|
n >>= 4;
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
test "pcg sequence" {
|
|
var r = Pcg.init(0);
|
|
const s0: u64 = 0x9394bf54ce5d79de;
|
|
const s1: u64 = 0x84e9c579ef59bbf7;
|
|
r.seedTwo(s0, s1);
|
|
|
|
const seq = [_]u32{
|
|
2881561918,
|
|
3063928540,
|
|
1199791034,
|
|
2487695858,
|
|
1479648952,
|
|
3247963454,
|
|
};
|
|
|
|
for (seq) |s| {
|
|
expect(s == r.next());
|
|
}
|
|
}
|
|
|
|
// Xoroshiro128+ - http://xoroshiro.di.unimi.it/
|
|
//
|
|
// PRNG
|
|
pub const Xoroshiro128 = struct {
|
|
random: Random,
|
|
|
|
s: [2]u64,
|
|
|
|
pub fn init(init_s: u64) Xoroshiro128 {
|
|
var x = Xoroshiro128{
|
|
.random = Random{ .fillFn = fill },
|
|
.s = undefined,
|
|
};
|
|
|
|
x.seed(init_s);
|
|
return x;
|
|
}
|
|
|
|
fn next(self: *Xoroshiro128) u64 {
|
|
const s0 = self.s[0];
|
|
var s1 = self.s[1];
|
|
const r = s0 +% s1;
|
|
|
|
s1 ^= s0;
|
|
self.s[0] = math.rotl(u64, s0, @as(u8, 55)) ^ s1 ^ (s1 << 14);
|
|
self.s[1] = math.rotl(u64, s1, @as(u8, 36));
|
|
|
|
return r;
|
|
}
|
|
|
|
// Skip 2^64 places ahead in the sequence
|
|
fn jump(self: *Xoroshiro128) void {
|
|
var s0: u64 = 0;
|
|
var s1: u64 = 0;
|
|
|
|
const table = [_]u64{
|
|
0xbeac0467eba5facb,
|
|
0xd86b048b86aa9922,
|
|
};
|
|
|
|
inline for (table) |entry| {
|
|
var b: usize = 0;
|
|
while (b < 64) : (b += 1) {
|
|
if ((entry & (@as(u64, 1) << @intCast(u6, b))) != 0) {
|
|
s0 ^= self.s[0];
|
|
s1 ^= self.s[1];
|
|
}
|
|
_ = self.next();
|
|
}
|
|
}
|
|
|
|
self.s[0] = s0;
|
|
self.s[1] = s1;
|
|
}
|
|
|
|
fn seed(self: *Xoroshiro128, init_s: u64) void {
|
|
// Xoroshiro requires 128-bits of seed.
|
|
var gen = SplitMix64.init(init_s);
|
|
|
|
self.s[0] = gen.next();
|
|
self.s[1] = gen.next();
|
|
}
|
|
|
|
fn fill(r: *Random, buf: []u8) void {
|
|
const self = @fieldParentPtr(Xoroshiro128, "random", r);
|
|
|
|
var i: usize = 0;
|
|
const aligned_len = buf.len - (buf.len & 7);
|
|
|
|
// Complete 8 byte segments.
|
|
while (i < aligned_len) : (i += 8) {
|
|
var n = self.next();
|
|
comptime var j: usize = 0;
|
|
inline while (j < 8) : (j += 1) {
|
|
buf[i + j] = @truncate(u8, n);
|
|
n >>= 8;
|
|
}
|
|
}
|
|
|
|
// Remaining. (cuts the stream)
|
|
if (i != buf.len) {
|
|
var n = self.next();
|
|
while (i < buf.len) : (i += 1) {
|
|
buf[i] = @truncate(u8, n);
|
|
n >>= 8;
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
test "xoroshiro sequence" {
|
|
var r = Xoroshiro128.init(0);
|
|
r.s[0] = 0xaeecf86f7878dd75;
|
|
r.s[1] = 0x01cd153642e72622;
|
|
|
|
const seq1 = [_]u64{
|
|
0xb0ba0da5bb600397,
|
|
0x18a08afde614dccc,
|
|
0xa2635b956a31b929,
|
|
0xabe633c971efa045,
|
|
0x9ac19f9706ca3cac,
|
|
0xf62b426578c1e3fb,
|
|
};
|
|
|
|
for (seq1) |s| {
|
|
expect(s == r.next());
|
|
}
|
|
|
|
r.jump();
|
|
|
|
const seq2 = [_]u64{
|
|
0x95344a13556d3e22,
|
|
0xb4fb32dafa4d00df,
|
|
0xb2011d9ccdcfe2dd,
|
|
0x05679a9b2119b908,
|
|
0xa860a1da7c9cd8a0,
|
|
0x658a96efe3f86550,
|
|
};
|
|
|
|
for (seq2) |s| {
|
|
expect(s == r.next());
|
|
}
|
|
}
|
|
|
|
// ISAAC64 - http://www.burtleburtle.net/bob/rand/isaacafa.html
|
|
//
|
|
// CSPRNG
|
|
//
|
|
// Follows the general idea of the implementation from here with a few shortcuts.
|
|
// https://doc.rust-lang.org/rand/src/rand/prng/isaac64.rs.html
|
|
pub const Isaac64 = struct {
|
|
random: Random,
|
|
|
|
r: [256]u64,
|
|
m: [256]u64,
|
|
a: u64,
|
|
b: u64,
|
|
c: u64,
|
|
i: usize,
|
|
|
|
pub fn init(init_s: u64) Isaac64 {
|
|
var isaac = Isaac64{
|
|
.random = Random{ .fillFn = fill },
|
|
.r = undefined,
|
|
.m = undefined,
|
|
.a = undefined,
|
|
.b = undefined,
|
|
.c = undefined,
|
|
.i = undefined,
|
|
};
|
|
|
|
// seed == 0 => same result as the unseeded reference implementation
|
|
isaac.seed(init_s, 1);
|
|
return isaac;
|
|
}
|
|
|
|
fn step(self: *Isaac64, mix: u64, base: usize, comptime m1: usize, comptime m2: usize) void {
|
|
const x = self.m[base + m1];
|
|
self.a = mix +% self.m[base + m2];
|
|
|
|
const y = self.a +% self.b +% self.m[@intCast(usize, (x >> 3) % self.m.len)];
|
|
self.m[base + m1] = y;
|
|
|
|
self.b = x +% self.m[@intCast(usize, (y >> 11) % self.m.len)];
|
|
self.r[self.r.len - 1 - base - m1] = self.b;
|
|
}
|
|
|
|
fn refill(self: *Isaac64) void {
|
|
const midpoint = self.r.len / 2;
|
|
|
|
self.c +%= 1;
|
|
self.b +%= self.c;
|
|
|
|
{
|
|
var i: usize = 0;
|
|
while (i < midpoint) : (i += 4) {
|
|
self.step(~(self.a ^ (self.a << 21)), i + 0, 0, midpoint);
|
|
self.step(self.a ^ (self.a >> 5), i + 1, 0, midpoint);
|
|
self.step(self.a ^ (self.a << 12), i + 2, 0, midpoint);
|
|
self.step(self.a ^ (self.a >> 33), i + 3, 0, midpoint);
|
|
}
|
|
}
|
|
|
|
{
|
|
var i: usize = 0;
|
|
while (i < midpoint) : (i += 4) {
|
|
self.step(~(self.a ^ (self.a << 21)), i + 0, midpoint, 0);
|
|
self.step(self.a ^ (self.a >> 5), i + 1, midpoint, 0);
|
|
self.step(self.a ^ (self.a << 12), i + 2, midpoint, 0);
|
|
self.step(self.a ^ (self.a >> 33), i + 3, midpoint, 0);
|
|
}
|
|
}
|
|
|
|
self.i = 0;
|
|
}
|
|
|
|
fn next(self: *Isaac64) u64 {
|
|
if (self.i >= self.r.len) {
|
|
self.refill();
|
|
}
|
|
|
|
const value = self.r[self.i];
|
|
self.i += 1;
|
|
return value;
|
|
}
|
|
|
|
fn seed(self: *Isaac64, init_s: u64, comptime rounds: usize) void {
|
|
// We ignore the multi-pass requirement since we don't currently expose full access to
|
|
// seeding the self.m array completely.
|
|
mem.set(u64, self.m[0..], 0);
|
|
self.m[0] = init_s;
|
|
|
|
// prescrambled golden ratio constants
|
|
var a = [_]u64{
|
|
0x647c4677a2884b7c,
|
|
0xb9f8b322c73ac862,
|
|
0x8c0ea5053d4712a0,
|
|
0xb29b2e824a595524,
|
|
0x82f053db8355e0ce,
|
|
0x48fe4a0fa5a09315,
|
|
0xae985bf2cbfc89ed,
|
|
0x98f5704f6c44c0ab,
|
|
};
|
|
|
|
comptime var i: usize = 0;
|
|
inline while (i < rounds) : (i += 1) {
|
|
var j: usize = 0;
|
|
while (j < self.m.len) : (j += 8) {
|
|
comptime var x1: usize = 0;
|
|
inline while (x1 < 8) : (x1 += 1) {
|
|
a[x1] +%= self.m[j + x1];
|
|
}
|
|
|
|
a[0] -%= a[4];
|
|
a[5] ^= a[7] >> 9;
|
|
a[7] +%= a[0];
|
|
a[1] -%= a[5];
|
|
a[6] ^= a[0] << 9;
|
|
a[0] +%= a[1];
|
|
a[2] -%= a[6];
|
|
a[7] ^= a[1] >> 23;
|
|
a[1] +%= a[2];
|
|
a[3] -%= a[7];
|
|
a[0] ^= a[2] << 15;
|
|
a[2] +%= a[3];
|
|
a[4] -%= a[0];
|
|
a[1] ^= a[3] >> 14;
|
|
a[3] +%= a[4];
|
|
a[5] -%= a[1];
|
|
a[2] ^= a[4] << 20;
|
|
a[4] +%= a[5];
|
|
a[6] -%= a[2];
|
|
a[3] ^= a[5] >> 17;
|
|
a[5] +%= a[6];
|
|
a[7] -%= a[3];
|
|
a[4] ^= a[6] << 14;
|
|
a[6] +%= a[7];
|
|
|
|
comptime var x2: usize = 0;
|
|
inline while (x2 < 8) : (x2 += 1) {
|
|
self.m[j + x2] = a[x2];
|
|
}
|
|
}
|
|
}
|
|
|
|
mem.set(u64, self.r[0..], 0);
|
|
self.a = 0;
|
|
self.b = 0;
|
|
self.c = 0;
|
|
self.i = self.r.len; // trigger refill on first value
|
|
}
|
|
|
|
fn fill(r: *Random, buf: []u8) void {
|
|
const self = @fieldParentPtr(Isaac64, "random", r);
|
|
|
|
var i: usize = 0;
|
|
const aligned_len = buf.len - (buf.len & 7);
|
|
|
|
// Fill complete 64-byte segments
|
|
while (i < aligned_len) : (i += 8) {
|
|
var n = self.next();
|
|
comptime var j: usize = 0;
|
|
inline while (j < 8) : (j += 1) {
|
|
buf[i + j] = @truncate(u8, n);
|
|
n >>= 8;
|
|
}
|
|
}
|
|
|
|
// Fill trailing, ignoring excess (cut the stream).
|
|
if (i != buf.len) {
|
|
var n = self.next();
|
|
while (i < buf.len) : (i += 1) {
|
|
buf[i] = @truncate(u8, n);
|
|
n >>= 8;
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
test "isaac64 sequence" {
|
|
var r = Isaac64.init(0);
|
|
|
|
// from reference implementation
|
|
const seq = [_]u64{
|
|
0xf67dfba498e4937c,
|
|
0x84a5066a9204f380,
|
|
0xfee34bd5f5514dbb,
|
|
0x4d1664739b8f80d6,
|
|
0x8607459ab52a14aa,
|
|
0x0e78bc5a98529e49,
|
|
0xfe5332822ad13777,
|
|
0x556c27525e33d01a,
|
|
0x08643ca615f3149f,
|
|
0xd0771faf3cb04714,
|
|
0x30e86f68a37b008d,
|
|
0x3074ebc0488a3adf,
|
|
0x270645ea7a2790bc,
|
|
0x5601a0a8d3763c6a,
|
|
0x2f83071f53f325dd,
|
|
0xb9090f3d42d2d2ea,
|
|
};
|
|
|
|
for (seq) |s| {
|
|
expect(s == r.next());
|
|
}
|
|
}
|
|
|
|
/// Sfc64 pseudo-random number generator from Practically Random.
|
|
/// Fastest engine of pracrand and smallest footprint.
|
|
/// See http://pracrand.sourceforge.net/
|
|
pub const Sfc64 = struct {
|
|
random: Random,
|
|
|
|
a: u64 = undefined,
|
|
b: u64 = undefined,
|
|
c: u64 = undefined,
|
|
counter: u64 = undefined,
|
|
|
|
const Rotation = 24;
|
|
const RightShift = 11;
|
|
const LeftShift = 3;
|
|
|
|
pub fn init(init_s: u64) Sfc64 {
|
|
var x = Sfc64{
|
|
.random = Random{ .fillFn = fill },
|
|
};
|
|
|
|
x.seed(init_s);
|
|
return x;
|
|
}
|
|
|
|
fn next(self: *Sfc64) u64 {
|
|
const tmp = self.a +% self.b +% self.counter;
|
|
self.counter += 1;
|
|
self.a = self.b ^ (self.b >> RightShift);
|
|
self.b = self.c +% (self.c << LeftShift);
|
|
self.c = math.rotl(u64, self.c, Rotation) +% tmp;
|
|
return tmp;
|
|
}
|
|
|
|
fn seed(self: *Sfc64, init_s: u64) void {
|
|
self.a = init_s;
|
|
self.b = init_s;
|
|
self.c = init_s;
|
|
self.counter = 1;
|
|
var i: u32 = 0;
|
|
while (i < 12) : (i += 1) {
|
|
_ = self.next();
|
|
}
|
|
}
|
|
|
|
fn fill(r: *Random, buf: []u8) void {
|
|
const self = @fieldParentPtr(Sfc64, "random", r);
|
|
|
|
var i: usize = 0;
|
|
const aligned_len = buf.len - (buf.len & 7);
|
|
|
|
// Complete 8 byte segments.
|
|
while (i < aligned_len) : (i += 8) {
|
|
var n = self.next();
|
|
comptime var j: usize = 0;
|
|
inline while (j < 8) : (j += 1) {
|
|
buf[i + j] = @truncate(u8, n);
|
|
n >>= 8;
|
|
}
|
|
}
|
|
|
|
// Remaining. (cuts the stream)
|
|
if (i != buf.len) {
|
|
var n = self.next();
|
|
while (i < buf.len) : (i += 1) {
|
|
buf[i] = @truncate(u8, n);
|
|
n >>= 8;
|
|
}
|
|
}
|
|
}
|
|
};
|
|
|
|
test "Sfc64 sequence" {
|
|
// Unfortunately there does not seem to be an official test sequence.
|
|
var r = Sfc64.init(0);
|
|
|
|
const seq = [_]u64{
|
|
0x3acfa029e3cc6041,
|
|
0xf5b6515bf2ee419c,
|
|
0x1259635894a29b61,
|
|
0xb6ae75395f8ebd6,
|
|
0x225622285ce302e2,
|
|
0x520d28611395cb21,
|
|
0xdb909c818901599d,
|
|
0x8ffd195365216f57,
|
|
0xe8c4ad5e258ac04a,
|
|
0x8f8ef2c89fdb63ca,
|
|
0xf9865b01d98d8e2f,
|
|
0x46555871a65d08ba,
|
|
0x66868677c6298fcd,
|
|
0x2ce15a7e6329f57d,
|
|
0xb2f1833ca91ca79,
|
|
0x4b0890ac9bf453ca,
|
|
};
|
|
|
|
for (seq) |s| {
|
|
expectEqual(s, r.next());
|
|
}
|
|
}
|
|
|
|
// Actual Random helper function tests, pcg engine is assumed correct.
|
|
test "Random float" {
|
|
var prng = DefaultPrng.init(0);
|
|
|
|
var i: usize = 0;
|
|
while (i < 1000) : (i += 1) {
|
|
const val1 = prng.random.float(f32);
|
|
expect(val1 >= 0.0);
|
|
expect(val1 < 1.0);
|
|
|
|
const val2 = prng.random.float(f64);
|
|
expect(val2 >= 0.0);
|
|
expect(val2 < 1.0);
|
|
}
|
|
}
|
|
|
|
test "Random shuffle" {
|
|
var prng = DefaultPrng.init(0);
|
|
|
|
var seq = [_]u8{ 0, 1, 2, 3, 4 };
|
|
var seen = [_]bool{false} ** 5;
|
|
|
|
var i: usize = 0;
|
|
while (i < 1000) : (i += 1) {
|
|
prng.random.shuffle(u8, seq[0..]);
|
|
seen[seq[0]] = true;
|
|
expect(sumArray(seq[0..]) == 10);
|
|
}
|
|
|
|
// we should see every entry at the head at least once
|
|
for (seen) |e| {
|
|
expect(e == true);
|
|
}
|
|
}
|
|
|
|
fn sumArray(s: []const u8) u32 {
|
|
var r: u32 = 0;
|
|
for (s) |e|
|
|
r += e;
|
|
return r;
|
|
}
|
|
|
|
test "Random range" {
|
|
var prng = DefaultPrng.init(0);
|
|
testRange(&prng.random, -4, 3);
|
|
testRange(&prng.random, -4, -1);
|
|
testRange(&prng.random, 10, 14);
|
|
testRange(&prng.random, -0x80, 0x7f);
|
|
}
|
|
|
|
fn testRange(r: *Random, start: i8, end: i8) void {
|
|
testRangeBias(r, start, end, true);
|
|
testRangeBias(r, start, end, false);
|
|
}
|
|
fn testRangeBias(r: *Random, start: i8, end: i8, biased: bool) void {
|
|
const count = @intCast(usize, @as(i32, end) - @as(i32, start));
|
|
var values_buffer = [_]bool{false} ** 0x100;
|
|
const values = values_buffer[0..count];
|
|
var i: usize = 0;
|
|
while (i < count) {
|
|
const value: i32 = if (biased) r.intRangeLessThanBiased(i8, start, end) else r.intRangeLessThan(i8, start, end);
|
|
const index = @intCast(usize, value - start);
|
|
if (!values[index]) {
|
|
i += 1;
|
|
values[index] = true;
|
|
}
|
|
}
|
|
}
|