• James <james gmail.com> Nov 05 2008
• "Steven Schveighoffer" <schveiguy yahoo.com> Nov 06 2008
• "Denis Koroskin" <2korden gmail.com> Nov 06 2008
• James <James gmail.com> Nov 06 2008

James <james gmail.com> writes:

im having problem in code below, while making my own file handler. the data
stored in buffer, so i can recall portion of data in diff format and length
like int,short,etc.  but im stuck with function getb() below. any suggestion?
thks.

struct T_FILE_RAM {
  ubyte[] buffer;
  int offset;

void getb(void* buf, int size) {
	buf=&b[offset..offset+size]; //<-- prob here
}

void read(out uint x) { getb(&x, x.sizeof); }
void read(out ushort x) { getb(&x, x.sizeof); }

}

"Steven Schveighoffer" <schveiguy yahoo.com> writes:

"James" wrote
 im having problem in code below, while making my own file handler. the 
 data stored in buffer, so i can recall portion of data in diff format and 
 length like int,short,etc.  but im stuck with function getb() below. any 
 suggestion? thks.

 struct T_FILE_RAM {
  ubyte[] buffer;
  int offset;

 void getb(void* buf, int size) {
 buf=&b[offset..offset+size]; //<-- prob here
 }

 void read(out uint x) { getb(&x, x.sizeof); }
 void read(out ushort x) { getb(&x, x.sizeof); }

 }


I think you meant this?

buf[0..size] = buffer[offset..offset+size];
And also, you need to increment offset, no?
offset += size.

I'd also recommend using a template:

void getb(T)(ref T t)
{
    auto size = t.sizeof;
    auto buf = (cast(ubyte *)&t)[0..size];
    buf[] = buffer[offset..offset+size];
    offset += size;
}

Now you don't need to implement each type, and you can call like this:
int x;
ushort y;
getb(x); // reads 4 bytes
getb(y); // reads 2 bytes

-Steve 

"Denis Koroskin" <2korden gmail.com> writes:

On Thu, 06 Nov 2008 18:22:36 +0300, Steven Schveighoffer  
<schveiguy yahoo.com> wrote:

 "James" wrote
 im having problem in code below, while making my own file handler. the
 data stored in buffer, so i can recall portion of data in diff format  
 and
 length like int,short,etc.  but im stuck with function getb() below. any
 suggestion? thks.

 struct T_FILE_RAM {
  ubyte[] buffer;
  int offset;

 void getb(void* buf, int size) {
 buf=&b[offset..offset+size]; //<-- prob here
 }

 void read(out uint x) { getb(&x, x.sizeof); }
 void read(out ushort x) { getb(&x, x.sizeof); }

 }


 I think you meant this?

 buf[0..size] = buffer[offset..offset+size];
 And also, you need to increment offset, no?
 offset += size.

 I'd also recommend using a template:

 void getb(T)(ref T t)
 {
     auto size = t.sizeof;
     auto buf = (cast(ubyte *)&t)[0..size];
     buf[] = buffer[offset..offset+size];
     offset += size;
 }

 Now you don't need to implement each type, and you can call like this:
 int x;
 ushort y;
 getb(x); // reads 4 bytes
 getb(y); // reads 2 bytes

 -Steve


Good solution also cares about endianess.

Also take a look at tango.io.protocol - it should cover all your needs.

James <James gmail.com> writes:

Steven Schveighoffer Wrote:

 "James" wrote
 im having problem in code below, while making my own file handler. the 
 data stored in buffer, so i can recall portion of data in diff format and 
 length like int,short,etc.  but im stuck with function getb() below. any 
 suggestion? thks.

 struct T_FILE_RAM {
  ubyte[] buffer;
  int offset;

 void getb(void* buf, int size) {
 buf=&b[offset..offset+size]; //<-- prob here
 }

 void read(out uint x) { getb(&x, x.sizeof); }
 void read(out ushort x) { getb(&x, x.sizeof); }

 }


 I think you meant this?
 
 buf[0..size] = buffer[offset..offset+size];
 And also, you need to increment offset, no?
 offset += size.
 
 I'd also recommend using a template:
 
 void getb(T)(ref T t)
 {
     auto size = t.sizeof;
     auto buf = (cast(ubyte *)&t)[0..size];
     buf[] = buffer[offset..offset+size];
     offset += size;
 }
 
 Now you don't need to implement each type, and you can call like this:
 int x;
 ushort y;
 getb(x); // reads 4 bytes
 getb(y); // reads 2 bytes
 
 -Steve 
 
 


thanks, exactly what im looking for. endianness isnt a problem at this point as
im not working on a portable project.