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test lots of types

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This commit is contained in:
Josh Wolfe 2018-11-21 18:47:32 -05:00
parent 49b49618d2
commit eed7b48fe3
1 changed files with 35 additions and 2 deletions
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37
std/rand/index.zig
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@ -60,7 +60,8 @@ pub const Random = struct {
/// 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 {
assert(T.is_signed == false);
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);
@ -83,7 +84,8 @@ pub const Random = struct {
/// 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 {
assert(T.is_signed == false);
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);
@ -431,6 +433,37 @@ fn testRandomIntAtMost() void {
assert(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.
assert(r.random.uintLessThanBiased(u1, 1) == 0);
assert(r.random.uintLessThanBiased(u32, 10) < 10);
assert(r.random.uintLessThanBiased(u64, 20) < 20);
assert(r.random.uintAtMostBiased(u0, 0) == 0);
assert(r.random.uintAtMostBiased(u1, 0) <= 0);
assert(r.random.uintAtMostBiased(u32, 10) <= 10);
assert(r.random.uintAtMostBiased(u64, 20) <= 20);
assert(r.random.intRangeLessThanBiased(u1, 0, 1) == 0);
assert(r.random.intRangeLessThanBiased(i1, -1, 0) == -1);
assert(r.random.intRangeLessThanBiased(u32, 10, 20) >= 10);
assert(r.random.intRangeLessThanBiased(i32, 10, 20) >= 10);
assert(r.random.intRangeLessThanBiased(u64, 20, 40) >= 20);
assert(r.random.intRangeLessThanBiased(i64, 20, 40) >= 20);
// uncomment for broken module error:
//assert(r.random.intRangeAtMostBiased(u0, 0, 0) == 0);
assert(r.random.intRangeAtMostBiased(u1, 0, 1) >= 0);
assert(r.random.intRangeAtMostBiased(i1, -1, 0) >= -1);
assert(r.random.intRangeAtMostBiased(u32, 10, 20) >= 10);
assert(r.random.intRangeAtMostBiased(i32, 10, 20) >= 10);
assert(r.random.intRangeAtMostBiased(u64, 20, 40) >= 20);
assert(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