Hi there,

I've set up a server and a client application and I want to be able to send a struct with fx. an integer and a char[]. So first I convert it to a ubyte[] like this:

..
void write(T)(T input)
{
    buf ~= *(cast(ubyte[T.sizeof]*)&input)[0 .. T.sizeof];
}

Then I send the ubyte[] over through TCP via a SocketStream. On the client-side I read and convert the ubyte[] back to the struct:

uint len = ss.read(buffer);
auto mem = new mem_stream(buffer[0 .. len]);
data d = mem.read!(data);
writefln("[id:%d] len=%d, data=%s (%d)", d.id, len, d.content, d.content.sizeof);

Which outputs:    [id:100] len=12, data= (8)

The read function:
..
int pos = 0;
..
T read(T)()
{
     T output = *(cast(T*)(buf[pos .. pos + T.sizeof].ptr));
     pos += T.sizeof;
     return output;
}

The Integer got sent perfectly (and i does the same with additional ulongs etc.) but the char[] did not, though, it is still the same size.

So why can't I send the char[]? is it because it is a array of pointers to the address-space of the server?

Thank you in advance :)

(Btw. My files are also attatched)

Reply to SirErugor,

> Hi there,
> 
> I've set up a server and a client application and I want to be able to
> send a struct with fx. an integer and a char[]. So first I convert it
> to a ubyte[] like this:
> 
> ..
> void write(T)(T input)
> {
> buf ~= *(cast(ubyte[T.sizeof]*)&input)[0 .. T.sizeof];
> }
> Then I send the ubyte[] over through TCP via a SocketStream. On the
> client-side I read and convert the ubyte[] back to the struct:
> 
> uint len = ss.read(buffer);
> auto mem = new mem_stream(buffer[0 .. len]);
> data d = mem.read!(data);
> writefln("[id:%d] len=%d, data=%s (%d)", d.id, len, d.content,
> d.content.sizeof);
> Which outputs:    [id:100] len=12, data= (8)
> 
> The read function:
> ..
> int pos = 0;
> ..
> T read(T)()
> {
> T output = *(cast(T*)(buf[pos .. pos + T.sizeof].ptr));
> pos += T.sizeof;
> return output;
> }
> The Integer got sent perfectly (and i does the same with additional
> ulongs etc.) but the char[] did not, though, it is still the same
> size.
> 
> So why can't I send the char[]? is it because it is a array of
> pointers to the address-space of the server?
> 
> Thank you in advance :)
> 
> (Btw. My files are also attatched)
> 


char[] is by reference. under the hood it is a pointer/length pair.

Somewhere I have a code generator that tries to make this work.

Reply to Benjamin,

> Reply to SirErugor,
> 
>> Hi there,
>> 
>> I've set up a server and a client application and I want to be able
>> to send a struct with fx. an integer and a char[]. So first I convert
>> it to a ubyte[] like this:
>> 
>> ..
>> void write(T)(T input)
>> {
>> buf ~= *(cast(ubyte[T.sizeof]*)&input)[0 .. T.sizeof];
>> }
>> Then I send the ubyte[] over through TCP via a SocketStream. On the
>> client-side I read and convert the ubyte[] back to the struct:
>> uint len = ss.read(buffer);
>> auto mem = new mem_stream(buffer[0 .. len]);
>> data d = mem.read!(data);
>> writefln("[id:%d] len=%d, data=%s (%d)", d.id, len, d.content,
>> d.content.sizeof);
>> Which outputs:    [id:100] len=12, data= (8)
>> The read function:
>> ..
>> int pos = 0;
>> ..
>> T read(T)()
>> {
>> T output = *(cast(T*)(buf[pos .. pos + T.sizeof].ptr));
>> pos += T.sizeof;
>> return output;
>> }
>> The Integer got sent perfectly (and i does the same with additional
>> ulongs etc.) but the char[] did not, though, it is still the same
>> size.
>> So why can't I send the char[]? is it because it is a array of
>> pointers to the address-space of the server?
>> 
>> Thank you in advance :)
>> 
>> (Btw. My files are also attatched)
>> 
> char[] is by reference. under the hood it is a pointer/length pair.
> 
> Somewhere I have a code generator that tries to make this work.
> 

ftp://ftp.novell.uidaho.edu/public_html/netidl_0_12_sdk.zip

somewhere in there is a template that will suck up arrays (and arrays of arrays, ...) and let you send them over the wire.

try running the program on a file like this

interface foo
{
 void bar(char[] i);
 void big(char[][] i);
}

I haven't looked at it for ages so I won't make any claims about how well it will work.

SirErugor wrote:
> Hi there,
> 
> I've set up a server and a client application and I want to be able to send a struct with fx. an integer and a char[]. So first I convert it to a ubyte[] like this:
> 

This is rather easy to achieve with templates
I needed to do something similar a bit back, so here's the code I used:

template isArray(T) { const isArray=false; }
template isArray(T: T[]) { const isArray=true; }

/// serialize
void ser(T)(T value, void delegate(char[]) dg) {
  static if (isArray!(T)) {
    /// First dump the length (as uint, so it's fixed across platforms), then the data
    /// \todo special case for char[] arrays
    ser!(uint)(value.length, dg);
    foreach (element; value) ser(element, dg);
  } else {
    static if (is(T==struct)) {
      /// Just serialize the elements in order
      foreach (element; value.tupleof) ser(element, dg);
    } else {
      dg((cast(char*)&value)[0..value.sizeof]);
    }
  }
}

void ser(T, dummy=void)(T value, inout char[] target) {
  ser!(T)(value, (char[] c) { target~=c; });
}

char[] splinter(inout char[] c, size_t amount) {
  assert(c.length!<amount);
  auto res=c[0..amount];
  c=c[amount..$];
  return res;
}

T carve(T)(inout char[] t) {
  T result;
  static if (isArray!(T)) {
    result.length=carve!(uint)(t);
    foreach (inout elem; result) elem=carve!(typeof(result[0]))(t);
  } else {
    static if (is(T==struct)) {
      foreach (idx, bogus; result.tupleof)
        result.tupleof[idx]=carve!(typeof(bogus))(t);
    } else {
      result=*(cast(T*)(splinter(t, T.sizeof).ptr));
    }
  }
  return result;
}


Use it like

struct test {
  int e;
  char[] f;
}
char[] send; test t;
ser(t, (char[] c) { send~=c; });
/* Now send "send" over the socket .. at the other end: */
char[] received; test t=carve!(test)(received);

Greetings  --downs

BCS Wrote:

> Reply to Benjamin,
> 
> ftp://ftp.novell.uidaho.edu/public_html/netidl_0_12_sdk.zip
> 
> somewhere in there is a template that will suck up arrays (and arrays of arrays, ...) and let you send them over the wire.
> 
> try running the program on a file like this
> 
> interface foo
> {
>   void bar(char[] i);
>   void big(char[][] i);
> }
> 
> I haven't looked at it for ages so I won't make any claims about how well it will work.

Thanks BCS,

But I cannot access the file? Not even as anonymous.
Could you please either post the file here or send it to my email?  :-)

Cheers!

Reply to SirErugor,

> BCS Wrote:
> 
>> Reply to Benjamin,
>> 
>> ftp://ftp.novell.uidaho.edu/public_html/netidl_0_12_sdk.zip
>> 
>> somewhere in there is a template that will suck up arrays (and arrays
>> of arrays, ...) and let you send them over the wire.
>> 
>> try running the program on a file like this
>> 
>> interface foo
>> {
>> void bar(char[] i);
>> void big(char[][] i);
>> }
>> I haven't looked at it for ages so I won't make any claims about how
>> well it will work.
>> 
> Thanks BCS,
> 
> But I cannot access the file? Not even as anonymous. Could you please
> either post the file here or send it to my email?  :-)
> 
> Cheers!
> 


Damb stupid firefox. No, wait, That was my bad. <g>

http://www.uidaho.edu/~shro8822/netidl_0_12_sdk.zip

That should work.

Downs Wrote:
> This is rather easy to achieve with templates
> I needed to do something similar a bit back, so here's the code I used:
> 
> template isArray(T) { const isArray=false; }
> template isArray(T: T[]) { const isArray=true; }
> 
> /// serialize
> void ser(T)(T value, void delegate(char[]) dg) {
>    static if (isArray!(T)) {
>      /// First dump the length (as uint, so it's fixed across platforms), then the data
>      /// \todo special case for char[] arrays
>      ser!(uint)(value.length, dg);
>      foreach (element; value) ser(element, dg);
>    } else {
>      static if (is(T==struct)) {
>        /// Just serialize the elements in order
>        foreach (element; value.tupleof) ser(element, dg);
>      } else {
>        dg((cast(char*)&value)[0..value.sizeof]);
>      }
>    }
> }
> 
> void ser(T, dummy=void)(T value, inout char[] target) {
>    ser!(T)(value, (char[] c) { target~=c; });
> }
> 
> char[] splinter(inout char[] c, size_t amount) {
>    assert(c.length!<amount);
>    auto res=c[0..amount];
>    c=c[amount..$];
>    return res;
> }
> 
> T carve(T)(inout char[] t) {
>    T result;
>    static if (isArray!(T)) {
>      result.length=carve!(uint)(t);
>      foreach (inout elem; result) elem=carve!(typeof(result[0]))(t);
>    } else {
>      static if (is(T==struct)) {
>        foreach (idx, bogus; result.tupleof)
>          result.tupleof[idx]=carve!(typeof(bogus))(t);
>      } else {
>        result=*(cast(T*)(splinter(t, T.sizeof).ptr));
>      }
>    }
>    return result;
> }
> 
> 
> Use it like
> 
> struct test {
>    int e;
>    char[] f;
> }
> char[] send; test t;
> ser(t, (char[] c) { send~=c; });
> /* Now send "send" over the socket .. at the other end: */
> char[] received; test t=carve!(test)(received);
> 
> Greetings  --downs

Thank you very much, Downs!
This works perfectly and I've gotten quite a better understanding on templates as well.

Cheers! :)

SirErugor wrote:
> Thank you very much, Downs!
> This works perfectly and I've gotten quite a better understanding on templates as well.
> 
> Cheers! :)

Glad to be of service :D