std.io.Writer.writeStructEndian: fix packed structs

This commit is contained in:
Andrew Kelley 2025-07-09 19:04:21 -07:00
parent dce08d9a57
commit aa1bdb43e0

View file

@ -794,12 +794,23 @@ pub fn writeStruct(w: *Writer, value: anytype) Error!void {
/// comptime-known and matches host endianness.
/// TODO: make sure this value is not a reference type
pub inline fn writeStructEndian(w: *Writer, value: anytype, endian: std.builtin.Endian) Error!void {
if (native_endian == endian) {
return w.writeStruct(value);
} else {
var copy = value;
std.mem.byteSwapAllFields(@TypeOf(value), &copy);
return w.writeStruct(copy);
switch (@typeInfo(@TypeOf(value))) {
.@"struct" => |info| switch (info.layout) {
.auto => @compileError("ill-defined memory layout"),
.@"extern" => {
if (native_endian == endian) {
return w.writeStruct(value);
} else {
var copy = value;
std.mem.byteSwapAllFields(@TypeOf(value), &copy);
return w.writeStruct(copy);
}
},
.@"packed" => {
return writeInt(w, info.backing_integer.?, @bitCast(value), endian);
},
},
else => @compileError("not a struct"),
}
}