zig/test/cases/cast.zig
2018-10-26 15:01:51 -04:00

455 lines
12 KiB
Zig

const std = @import("std");
const assert = std.debug.assert;
const mem = std.mem;
const maxInt = std.math.maxInt;
test "int to ptr cast" {
const x = usize(13);
const y = @intToPtr(*u8, x);
const z = @ptrToInt(y);
assert(z == 13);
}
test "integer literal to pointer cast" {
const vga_mem = @intToPtr(*u16, 0xB8000);
assert(@ptrToInt(vga_mem) == 0xB8000);
}
test "pointer reinterpret const float to int" {
const float: f64 = 5.99999999999994648725e-01;
const float_ptr = &float;
const int_ptr = @ptrCast(*const i32, float_ptr);
const int_val = int_ptr.*;
assert(int_val == 858993411);
}
test "implicitly cast indirect pointer to maybe-indirect pointer" {
const S = struct.{
const Self = @This();
x: u8,
fn constConst(p: *const *const Self) u8 {
return p.*.x;
}
fn maybeConstConst(p: ?*const *const Self) u8 {
return p.?.*.x;
}
fn constConstConst(p: *const *const *const Self) u8 {
return p.*.*.x;
}
fn maybeConstConstConst(p: ?*const *const *const Self) u8 {
return p.?.*.*.x;
}
};
const s = S.{ .x = 42 };
const p = &s;
const q = &p;
const r = &q;
assert(42 == S.constConst(q));
assert(42 == S.maybeConstConst(q));
assert(42 == S.constConstConst(r));
assert(42 == S.maybeConstConstConst(r));
}
test "explicit cast from integer to error type" {
testCastIntToErr(error.ItBroke);
comptime testCastIntToErr(error.ItBroke);
}
fn testCastIntToErr(err: error) void {
const x = @errorToInt(err);
const y = @intToError(x);
assert(error.ItBroke == y);
}
test "peer resolve arrays of different size to const slice" {
assert(mem.eql(u8, boolToStr(true), "true"));
assert(mem.eql(u8, boolToStr(false), "false"));
comptime assert(mem.eql(u8, boolToStr(true), "true"));
comptime assert(mem.eql(u8, boolToStr(false), "false"));
}
fn boolToStr(b: bool) []const u8 {
return if (b) "true" else "false";
}
test "peer resolve array and const slice" {
testPeerResolveArrayConstSlice(true);
comptime testPeerResolveArrayConstSlice(true);
}
fn testPeerResolveArrayConstSlice(b: bool) void {
const value1 = if (b) "aoeu" else ([]const u8)("zz");
const value2 = if (b) ([]const u8)("zz") else "aoeu";
assert(mem.eql(u8, value1, "aoeu"));
assert(mem.eql(u8, value2, "zz"));
}
test "implicitly cast from T to error!?T" {
castToOptionalTypeError(1);
comptime castToOptionalTypeError(1);
}
const A = struct.{
a: i32,
};
fn castToOptionalTypeError(z: i32) void {
const x = i32(1);
const y: error!?i32 = x;
assert((try y).? == 1);
const f = z;
const g: error!?i32 = f;
const a = A.{ .a = z };
const b: error!?A = a;
assert((b catch unreachable).?.a == 1);
}
test "implicitly cast from int to error!?T" {
implicitIntLitToOptional();
comptime implicitIntLitToOptional();
}
fn implicitIntLitToOptional() void {
const f: ?i32 = 1;
const g: error!?i32 = 1;
}
test "return null from fn() error!?&T" {
const a = returnNullFromOptionalTypeErrorRef();
const b = returnNullLitFromOptionalTypeErrorRef();
assert((try a) == null and (try b) == null);
}
fn returnNullFromOptionalTypeErrorRef() error!?*A {
const a: ?*A = null;
return a;
}
fn returnNullLitFromOptionalTypeErrorRef() error!?*A {
return null;
}
test "peer type resolution: ?T and T" {
assert(peerTypeTAndOptionalT(true, false).? == 0);
assert(peerTypeTAndOptionalT(false, false).? == 3);
comptime {
assert(peerTypeTAndOptionalT(true, false).? == 0);
assert(peerTypeTAndOptionalT(false, false).? == 3);
}
}
fn peerTypeTAndOptionalT(c: bool, b: bool) ?usize {
if (c) {
return if (b) null else usize(0);
}
return usize(3);
}
test "peer type resolution: [0]u8 and []const u8" {
assert(peerTypeEmptyArrayAndSlice(true, "hi").len == 0);
assert(peerTypeEmptyArrayAndSlice(false, "hi").len == 1);
comptime {
assert(peerTypeEmptyArrayAndSlice(true, "hi").len == 0);
assert(peerTypeEmptyArrayAndSlice(false, "hi").len == 1);
}
}
fn peerTypeEmptyArrayAndSlice(a: bool, slice: []const u8) []const u8 {
if (a) {
return []const u8.{};
}
return slice[0..1];
}
test "implicitly cast from [N]T to ?[]const T" {
assert(mem.eql(u8, castToOptionalSlice().?, "hi"));
comptime assert(mem.eql(u8, castToOptionalSlice().?, "hi"));
}
fn castToOptionalSlice() ?[]const u8 {
return "hi";
}
test "implicitly cast from [0]T to error![]T" {
testCastZeroArrayToErrSliceMut();
comptime testCastZeroArrayToErrSliceMut();
}
fn testCastZeroArrayToErrSliceMut() void {
assert((gimmeErrOrSlice() catch unreachable).len == 0);
}
fn gimmeErrOrSlice() error![]u8 {
return []u8.{};
}
test "peer type resolution: [0]u8, []const u8, and error![]u8" {
{
var data = "hi";
const slice = data[0..];
assert((try peerTypeEmptyArrayAndSliceAndError(true, slice)).len == 0);
assert((try peerTypeEmptyArrayAndSliceAndError(false, slice)).len == 1);
}
comptime {
var data = "hi";
const slice = data[0..];
assert((try peerTypeEmptyArrayAndSliceAndError(true, slice)).len == 0);
assert((try peerTypeEmptyArrayAndSliceAndError(false, slice)).len == 1);
}
}
fn peerTypeEmptyArrayAndSliceAndError(a: bool, slice: []u8) error![]u8 {
if (a) {
return []u8.{};
}
return slice[0..1];
}
test "resolve undefined with integer" {
testResolveUndefWithInt(true, 1234);
comptime testResolveUndefWithInt(true, 1234);
}
fn testResolveUndefWithInt(b: bool, x: i32) void {
const value = if (b) x else undefined;
if (b) {
assert(value == x);
}
}
test "implicit cast from &const [N]T to []const T" {
testCastConstArrayRefToConstSlice();
comptime testCastConstArrayRefToConstSlice();
}
fn testCastConstArrayRefToConstSlice() void {
const blah = "aoeu";
const const_array_ref = &blah;
assert(@typeOf(const_array_ref) == *const [4]u8);
const slice: []const u8 = const_array_ref;
assert(mem.eql(u8, slice, "aoeu"));
}
test "peer type resolution: error and [N]T" {
// TODO: implicit error!T to error!U where T can implicitly cast to U
//assert(mem.eql(u8, try testPeerErrorAndArray(0), "OK"));
//comptime assert(mem.eql(u8, try testPeerErrorAndArray(0), "OK"));
assert(mem.eql(u8, try testPeerErrorAndArray2(1), "OKK"));
comptime assert(mem.eql(u8, try testPeerErrorAndArray2(1), "OKK"));
}
//fn testPeerErrorAndArray(x: u8) error![]const u8 {
// return switch (x) {
// 0x00 => "OK",
// else => error.BadValue,
// };
//}
fn testPeerErrorAndArray2(x: u8) error![]const u8 {
return switch (x) {
0x00 => "OK",
0x01 => "OKK",
else => error.BadValue,
};
}
test "@floatToInt" {
testFloatToInts();
comptime testFloatToInts();
}
fn testFloatToInts() void {
const x = i32(1e4);
assert(x == 10000);
const y = @floatToInt(i32, f32(1e4));
assert(y == 10000);
expectFloatToInt(f16, 255.1, u8, 255);
expectFloatToInt(f16, 127.2, i8, 127);
expectFloatToInt(f16, -128.2, i8, -128);
expectFloatToInt(f32, 255.1, u8, 255);
expectFloatToInt(f32, 127.2, i8, 127);
expectFloatToInt(f32, -128.2, i8, -128);
expectFloatToInt(comptime_int, 1234, i16, 1234);
}
fn expectFloatToInt(comptime F: type, f: F, comptime I: type, i: I) void {
assert(@floatToInt(I, f) == i);
}
test "cast u128 to f128 and back" {
comptime testCast128();
testCast128();
}
fn testCast128() void {
assert(cast128Int(cast128Float(0x7fff0000000000000000000000000000)) == 0x7fff0000000000000000000000000000);
}
fn cast128Int(x: f128) u128 {
return @bitCast(u128, x);
}
fn cast128Float(x: u128) f128 {
return @bitCast(f128, x);
}
test "const slice widen cast" {
const bytes align(4) = []u8.{
0x12,
0x12,
0x12,
0x12,
};
const u32_value = @bytesToSlice(u32, bytes[0..])[0];
assert(u32_value == 0x12121212);
assert(@bitCast(u32, bytes) == 0x12121212);
}
test "single-item pointer of array to slice and to unknown length pointer" {
testCastPtrOfArrayToSliceAndPtr();
comptime testCastPtrOfArrayToSliceAndPtr();
}
fn testCastPtrOfArrayToSliceAndPtr() void {
var array = "aoeu";
const x: [*]u8 = &array;
x[0] += 1;
assert(mem.eql(u8, array[0..], "boeu"));
const y: []u8 = &array;
y[0] += 1;
assert(mem.eql(u8, array[0..], "coeu"));
}
test "cast *[1][*]const u8 to [*]const ?[*]const u8" {
const window_name = [1][*]const u8.{c"window name"};
const x: [*]const ?[*]const u8 = &window_name;
assert(mem.eql(u8, std.cstr.toSliceConst(x[0].?), "window name"));
}
test "@intCast comptime_int" {
const result = @intCast(i32, 1234);
assert(@typeOf(result) == i32);
assert(result == 1234);
}
test "@floatCast comptime_int and comptime_float" {
{
const result = @floatCast(f16, 1234);
assert(@typeOf(result) == f16);
assert(result == 1234.0);
}
{
const result = @floatCast(f16, 1234.0);
assert(@typeOf(result) == f16);
assert(result == 1234.0);
}
{
const result = @floatCast(f32, 1234);
assert(@typeOf(result) == f32);
assert(result == 1234.0);
}
{
const result = @floatCast(f32, 1234.0);
assert(@typeOf(result) == f32);
assert(result == 1234.0);
}
}
test "comptime_int @intToFloat" {
{
const result = @intToFloat(f16, 1234);
assert(@typeOf(result) == f16);
assert(result == 1234.0);
}
{
const result = @intToFloat(f32, 1234);
assert(@typeOf(result) == f32);
assert(result == 1234.0);
}
}
test "@bytesToSlice keeps pointer alignment" {
var bytes = []u8.{ 0x01, 0x02, 0x03, 0x04 };
const numbers = @bytesToSlice(u32, bytes[0..]);
comptime assert(@typeOf(numbers) == []align(@alignOf(@typeOf(bytes))) u32);
}
test "@intCast i32 to u7" {
var x: u128 = maxInt(u128);
var y: i32 = 120;
var z = x >> @intCast(u7, y);
assert(z == 0xff);
}
test "implicit cast undefined to optional" {
assert(MakeType(void).getNull() == null);
assert(MakeType(void).getNonNull() != null);
}
fn MakeType(comptime T: type) type {
return struct.{
fn getNull() ?T {
return null;
}
fn getNonNull() ?T {
return T(undefined);
}
};
}
test "implicit cast from *[N]T to ?[*]T" {
var x: ?[*]u16 = null;
var y: [4]u16 = [4]u16.{ 0, 1, 2, 3 };
x = &y;
assert(std.mem.eql(u16, x.?[0..4], y[0..4]));
x.?[0] = 8;
y[3] = 6;
assert(std.mem.eql(u16, x.?[0..4], y[0..4]));
}
test "implicit cast from *T to ?*c_void" {
var a: u8 = 1;
incrementVoidPtrValue(&a);
std.debug.assert(a == 2);
}
fn incrementVoidPtrValue(value: ?*c_void) void {
@ptrCast(*u8, value.?).* += 1;
}
test "implicit cast from [*]T to ?*c_void" {
var a = []u8.{ 3, 2, 1 };
incrementVoidPtrArray(a[0..].ptr, 3);
assert(std.mem.eql(u8, a, []u8.{ 4, 3, 2 }));
}
fn incrementVoidPtrArray(array: ?*c_void, len: usize) void {
var n: usize = 0;
while (n < len) : (n += 1) {
@ptrCast([*]u8, array.?)[n] += 1;
}
}
test "*usize to *void" {
var i = usize(0);
var v = @ptrCast(*void, &i);
v.* = {};
}
test "compile time int to ptr of function" {
foobar(FUNCTION_CONSTANT);
}
pub const FUNCTION_CONSTANT = @intToPtr(PFN_void, maxInt(usize));
pub const PFN_void = extern fn (*c_void) void;
fn foobar(func: PFN_void) void {
std.debug.assert(@ptrToInt(func) == maxInt(usize));
}
test "implicit ptr to *c_void" {
var a: u32 = 1;
var ptr: *c_void = &a;
var b: *u32 = @ptrCast(*u32, ptr);
assert(b.* == 1);
var ptr2: ?*c_void = &a;
var c: *u32 = @ptrCast(*u32, ptr2.?);
assert(c.* == 1);
}