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const std = @import("std");
const builtin = @import("builtin");
const expect = std.testing.expect;
const native_endian = builtin.target.cpu.arch.endian();
test "reinterpret bytes as integer with nonzero offset" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
try testReinterpretBytesAsInteger();
comptime try testReinterpretBytesAsInteger();
}
fn testReinterpretBytesAsInteger() !void {
const bytes = "\x12\x34\x56\x78\xab";
const expected = switch (native_endian) {
.Little => 0xab785634,
.Big => 0x345678ab,
};
try expect(@ptrCast(*align(1) const u32, bytes[1..5]).* == expected);
}
test "reinterpret an array over multiple elements, with no well-defined layout" {
if (builtin.zig_backend == .stage1) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
try testReinterpretWithOffsetAndNoWellDefinedLayout();
comptime try testReinterpretWithOffsetAndNoWellDefinedLayout();
}
fn testReinterpretWithOffsetAndNoWellDefinedLayout() !void {
const bytes: ?[5]?u8 = [5]?u8{ 0x12, 0x34, 0x56, 0x78, 0x9a };
const ptr = &bytes.?[1];
const copy: [4]?u8 = @ptrCast(*const [4]?u8, ptr).*;
_ = copy;
//try expect(@ptrCast(*align(1)?u8, bytes[1..5]).* == );
}
test "reinterpret bytes inside auto-layout struct as integer with nonzero offset" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
try testReinterpretStructWrappedBytesAsInteger();
comptime try testReinterpretStructWrappedBytesAsInteger();
}
fn testReinterpretStructWrappedBytesAsInteger() !void {
const S = struct { bytes: [5:0]u8 };
const obj = S{ .bytes = "\x12\x34\x56\x78\xab".* };
const expected = switch (native_endian) {
.Little => 0xab785634,
.Big => 0x345678ab,
};
try expect(@ptrCast(*align(1) const u32, obj.bytes[1..5]).* == expected);
}
test "reinterpret bytes of an array into an extern struct" {
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
try testReinterpretBytesAsExternStruct();
comptime try testReinterpretBytesAsExternStruct();
}
fn testReinterpretBytesAsExternStruct() !void {
var bytes align(2) = [_]u8{ 1, 2, 3, 4, 5, 6 };
const S = extern struct {
a: u8,
b: u16,
c: u8,
};
var ptr = @ptrCast(*const S, &bytes);
var val = ptr.c;
try expect(val == 5);
}
test "reinterpret bytes of an extern struct (with under-aligned fields) into another" {
if (builtin.zig_backend == .stage1) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO: Under-aligned fields are not yet supported in the CBE
try testReinterpretExternStructAsExternStruct();
comptime try testReinterpretExternStructAsExternStruct();
}
fn testReinterpretExternStructAsExternStruct() !void {
const S1 = extern struct {
a: u8,
b: u16,
c: u8,
};
comptime var bytes align(2) = S1{ .a = 0, .b = 0, .c = 5 };
const S2 = extern struct {
a: u32 align(2),
c: u8,
};
var ptr = @ptrCast(*const S2, &bytes);
var val = ptr.c;
try expect(val == 5);
}
test "reinterpret bytes of an extern struct into another" {
if (builtin.zig_backend == .stage1) return error.SkipZigTest;
try testReinterpretOverAlignedExternStructAsExternStruct();
comptime try testReinterpretOverAlignedExternStructAsExternStruct();
}
fn testReinterpretOverAlignedExternStructAsExternStruct() !void {
const S1 = extern struct {
a: u32,
b: u32,
c: u8,
};
comptime var bytes: S1 = .{ .a = 0, .b = 0, .c = 5 };
const S2 = extern struct {
a0: u32,
a1: u16,
a2: u16,
c: u8,
};
var ptr = @ptrCast(*const S2, &bytes);
var val = ptr.c;
try expect(val == 5);
}
test "lower reinterpreted comptime field ptr (with under-aligned fields)" {
if (builtin.zig_backend == .stage1) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_c) return error.SkipZigTest; // TODO: CBE does not yet support under-aligned fields
// Test lowering a field ptr
comptime var bytes align(2) = [_]u8{ 1, 2, 3, 4, 5, 6 };
const S = extern struct {
a: u32 align(2),
c: u8,
};
comptime var ptr = @ptrCast(*const S, &bytes);
var val = &ptr.c;
try expect(val.* == 5);
// Test lowering an elem ptr
comptime var src_value = S{ .a = 15, .c = 5 };
comptime var ptr2 = @ptrCast(*[@sizeOf(S)]u8, &src_value);
var val2 = &ptr2[4];
try expect(val2.* == 5);
}
test "lower reinterpreted comptime field ptr" {
if (builtin.zig_backend == .stage1) return error.SkipZigTest;
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_x86_64) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_wasm) return error.SkipZigTest; // TODO
// Test lowering a field ptr
comptime var bytes align(4) = [_]u8{ 1, 2, 3, 4, 5, 6, 7, 8 };
const S = extern struct {
a: u32,
c: u8,
};
comptime var ptr = @ptrCast(*const S, &bytes);
var val = &ptr.c;
try expect(val.* == 5);
// Test lowering an elem ptr
comptime var src_value = S{ .a = 15, .c = 5 };
comptime var ptr2 = @ptrCast(*[@sizeOf(S)]u8, &src_value);
var val2 = &ptr2[4];
try expect(val2.* == 5);
}
test "reinterpret struct field at comptime" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
const numNative = comptime Bytes.init(0x12345678);
if (native_endian != .Little) {
try expect(std.mem.eql(u8, &[_]u8{ 0x12, 0x34, 0x56, 0x78 }, &numNative.bytes));
} else {
try expect(std.mem.eql(u8, &[_]u8{ 0x78, 0x56, 0x34, 0x12 }, &numNative.bytes));
}
}
const Bytes = struct {
bytes: [4]u8,
pub fn init(v: u32) Bytes {
var res: Bytes = undefined;
@ptrCast(*align(1) u32, &res.bytes).* = v;
return res;
}
};
test "comptime ptrcast keeps larger alignment" {
comptime {
const a: u32 = 1234;
const p = @ptrCast([*]const u8, &a);
try expect(@TypeOf(p) == [*]align(@alignOf(u32)) const u8);
}
}
test "implicit optional pointer to optional anyopaque pointer" {
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
var buf: [4]u8 = "aoeu".*;
var x: ?[*]u8 = &buf;
var y: ?*anyopaque = x;
var z = @ptrCast(*[4]u8, y);
try expect(std.mem.eql(u8, z, "aoeu"));
}
test "@ptrCast slice to slice" {
if (builtin.zig_backend == .stage2_arm) return error.SkipZigTest; // TODO
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest; // TODO
const S = struct {
fn foo(slice: []u32) []i32 {
return @ptrCast([]i32, slice);
}
};
var buf: [4]u32 = .{ 0, 0, 0, 0 };
const alias = S.foo(&buf);
alias[1] = 42;
try expect(buf[1] == 42);
try expect(alias.len == 4);
}
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