digitalmars.D - array.reverse segfaults
- Moritz Warning (12/12) Oct 22 2008 Hi,
- Bill Baxter (10/22) Oct 22 2008 Does str.reverse actually return anything?
- Moritz Warning (5/34) Oct 22 2008 From the specs:
- Tomas Lindquist Olsen (9/24) Oct 22 2008 Simpler version:
- Tomas Lindquist Olsen (5/33) Oct 22 2008 When it tries to get the lower stride, it gets 0xFF from the table, but ...
- Moritz Warning (3/39) Oct 22 2008 I think it should do the same as on an invalid pointer: result in
- Denis Koroskin (7/46) Oct 22 2008 It should not pass the assert(isValidUtf8String(str)) prior to in-place ...
- Jarrett Billingsley (3/53) Oct 22 2008 I'd expect it to work like every other piece of code in the runtime
- Moritz Warning (4/55) Oct 22 2008 I was only referring to release builds.
Hi,
This piece of code segfaults on Debian Linux (with dmd 1.035):
Can someone tell me why?
char[] get(char[] str)
{
return new char[](4);
}
void main(char[][] args)
{
char[] str = get("abc");
char[] reversed = str.reverse; // <-- access violation
}
Oct 22 2008
On Wed, Oct 22, 2008 at 7:16 PM, Moritz Warning <moritzwarning web.de> wrote:
Hi,
This piece of code segfaults on Debian Linux (with dmd 1.035):
Can someone tell me why?
char[] get(char[] str)
{
return new char[](4);
}
void main(char[][] args)
{
char[] str = get("abc");
char[] reversed = str.reverse; // <-- access violation
}
Does str.reverse actually return anything?
I think you need to do that as:
str.reverse;
char[] reversed = str;
However, if it's not supposed to return anything, then it's a bug that
it compiles.
If it's supposed to return something, then it's a bug that it crashes.
Does it work doing it as two lines?
--bb
Oct 22 2008
Moritz Warning <moritzwarning web.de> On Wed, 22 Oct 2008 19:28:08 +0900, Bill Baxter wrote:On Wed, Oct 22, 2008 at 7:16 PM, Moritz Warning <moritzwarning web.de> wrote:From the specs: .reverse Reverses in place the order of the elements in the array. Returns the array. Removing the assignment to "reversed" doesn't change anything.Hi, This piece of code segfaults on Debian Linux (with dmd 1.035): Can someone tell me why? char[] get(char[] str) { return new char[](4); } void main(char[][] args) { char[] str = get("abc"); char[] reversed = str.reverse; // <-- access violation }Does str.reverse actually return anything? I think you need to do that as: str.reverse; char[] reversed = str; However, if it's not supposed to return anything, then it's a bug that it compiles. If it's supposed to return something, then it's a bug that it crashes. Does it work doing it as two lines? --bb
Oct 22 2008
Moritz Warning wrote:
Hi,
This piece of code segfaults on Debian Linux (with dmd 1.035):
Can someone tell me why?
char[] get(char[] str)
{
return new char[](4);
}
void main(char[][] args)
{
char[] str = get("abc");
char[] reversed = str.reverse; // <-- access violation
}
Simpler version:
void main()
{
char[4] str;
str.reverse;
}
Crashes in _adReverseChar when trying to memmove (3 - 255) bytes ;)
My best guess is that is just doesn't handle char.init values properly!
Oct 22 2008
Tomas Lindquist Olsen wrote:Moritz Warning wrote:When it tries to get the lower stride, it gets 0xFF from the table, but it doesn't check if this value is usable. Probably just ignoring these invalid bytes would make it work. But I think the real question is, what should _adReverseChar really do on invalid UTF-8 input?Hi, This piece of code segfaults on Debian Linux (with dmd 1.035): Can someone tell me why? char[] get(char[] str) { return new char[](4); } void main(char[][] args) { char[] str = get("abc"); char[] reversed = str.reverse; // <-- access violation }Simpler version: void main() { char[4] str; str.reverse; } Crashes in _adReverseChar when trying to memmove (3 - 255) bytes ;) My best guess is that is just doesn't handle char.init values properly!
Oct 22 2008
On Wed, 22 Oct 2008 13:10:20 +0200, Tomas Lindquist Olsen wrote:Tomas Lindquist Olsen wrote:I think it should do the same as on an invalid pointer: result in undefined behavior (=> segfault).Moritz Warning wrote:When it tries to get the lower stride, it gets 0xFF from the table, but it doesn't check if this value is usable. Probably just ignoring these invalid bytes would make it work. But I think the real question is, what should _adReverseChar really do on invalid UTF-8 input?Hi, This piece of code segfaults on Debian Linux (with dmd 1.035): Can someone tell me why? char[] get(char[] str) { return new char[](4); } void main(char[][] args) { char[] str = get("abc"); char[] reversed = str.reverse; // <-- access violation }Simpler version: void main() { char[4] str; str.reverse; } Crashes in _adReverseChar when trying to memmove (3 - 255) bytes ;) My best guess is that is just doesn't handle char.init values properly!
Oct 22 2008
On Wed, 22 Oct 2008 15:21:03 +0400, Moritz Warning <moritzwarning web.de> wrote:On Wed, 22 Oct 2008 13:10:20 +0200, Tomas Lindquist Olsen wrote:It should not pass the assert(isValidUtf8String(str)) prior to in-place reverse, thus throwing an exception in debug mode. Release behaviour is a subject to debat, but I think it should be more robust. Given wrong input it may produce whatever wrong output, but segfault? That's too bold.Tomas Lindquist Olsen wrote:I think it should do the same as on an invalid pointer: result in undefined behavior (=> segfault).Moritz Warning wrote:When it tries to get the lower stride, it gets 0xFF from the table, but it doesn't check if this value is usable. Probably just ignoring these invalid bytes would make it work. But I think the real question is, what should _adReverseChar really do on invalid UTF-8 input?Hi, This piece of code segfaults on Debian Linux (with dmd 1.035): Can someone tell me why? char[] get(char[] str) { return new char[](4); } void main(char[][] args) { char[] str = get("abc"); char[] reversed = str.reverse; // <-- access violation }Simpler version: void main() { char[4] str; str.reverse; } Crashes in _adReverseChar when trying to memmove (3 - 255) bytes ;) My best guess is that is just doesn't handle char.init values properly!
Oct 22 2008
On Wed, Oct 22, 2008 at 9:46 AM, Denis Koroskin <2korden gmail.com> wrote:On Wed, 22 Oct 2008 15:21:03 +0400, Moritz Warning <moritzwarning web.de> wrote:I'd expect it to work like every other piece of code in the runtime that deals with unicode and throw a UtfException or whatever it is.On Wed, 22 Oct 2008 13:10:20 +0200, Tomas Lindquist Olsen wrote:It should not pass the assert(isValidUtf8String(str)) prior to in-place reverse, thus throwing an exception in debug mode. Release behaviour is a subject to debat, but I think it should be more robust. Given wrong input it may produce whatever wrong output, but segfault? That's too bold.Tomas Lindquist Olsen wrote:I think it should do the same as on an invalid pointer: result in undefined behavior (=> segfault).Moritz Warning wrote:When it tries to get the lower stride, it gets 0xFF from the table, but it doesn't check if this value is usable. Probably just ignoring these invalid bytes would make it work. But I think the real question is, what should _adReverseChar really do on invalid UTF-8 input?Hi, This piece of code segfaults on Debian Linux (with dmd 1.035): Can someone tell me why? char[] get(char[] str) { return new char[](4); } void main(char[][] args) { char[] str = get("abc"); char[] reversed = str.reverse; // <-- access violation }Simpler version: void main() { char[4] str; str.reverse; } Crashes in _adReverseChar when trying to memmove (3 - 255) bytes ;) My best guess is that is just doesn't handle char.init values properly!
Oct 22 2008
On Wed, 22 Oct 2008 17:46:26 +0400, Denis Koroskin wrote:On Wed, 22 Oct 2008 15:21:03 +0400, Moritz Warning <moritzwarning web.de> wrote:I was only referring to release builds. Imho, If additional robustness doesn't result in a speed hit, then throwing an exception would be better.On Wed, 22 Oct 2008 13:10:20 +0200, Tomas Lindquist Olsen wrote:It should not pass the assert(isValidUtf8String(str)) prior to in-place reverse, thus throwing an exception in debug mode. Release behaviour is a subject to debat, but I think it should be more robust. Given wrong input it may produce whatever wrong output, but segfault? That's too bold.Tomas Lindquist Olsen wrote:I think it should do the same as on an invalid pointer: result in undefined behavior (=> segfault).Moritz Warning wrote:When it tries to get the lower stride, it gets 0xFF from the table, but it doesn't check if this value is usable. Probably just ignoring these invalid bytes would make it work. But I think the real question is, what should _adReverseChar really do on invalid UTF-8 input?Hi, This piece of code segfaults on Debian Linux (with dmd 1.035): Can someone tell me why? char[] get(char[] str) { return new char[](4); } void main(char[][] args) { char[] str = get("abc"); char[] reversed = str.reverse; // <-- access violation }Simpler version: void main() { char[4] str; str.reverse; } Crashes in _adReverseChar when trying to memmove (3 - 255) bytes ;) My best guess is that is just doesn't handle char.init values properly!
Oct 22 2008