Converting from C const(dchar*) to dstring

[Danyal Zia via Digitalmars-d-learn]

Hi, I like to print the strings from a C function that returns 
const(dchar*), but I can't make the conversion to dstring. I can 
convert vice versa by:


dstring text = Hello;
const(dchar)* str = toUTFz!(const(dchar)*)(text);
// passing it to C function prints Hello

However, I don't have the idea how can I go the other way. I 
tried several methods such as using to!dstring, toUTF32 etc which 
compiles successfully however printing them gives address of them 
instead of text.


Thanks,

Danyal Zia

Re: Converting from C const(dchar*) to dstring

[Steven Schveighoffer via Digitalmars-d-learn]

On Tue, 24 Jun 2014 13:37:41 -0400, Danyal Zia catofdan...@yahoo.com  
wrote:


Hi, I like to print the strings from a C function that returns  
const(dchar*), but I can't make the conversion to dstring. I can convert  
vice versa by:


dstring text = Hello;
const(dchar)* str = toUTFz!(const(dchar)*)(text);
// passing it to C function prints Hello

However, I don't have the idea how can I go the other way. I tried  
several methods such as using to!dstring, toUTF32 etc which compiles  
successfully however printing them gives address of them instead of text.


const(dchar *)x = ...;

// assuming 0 terminated
dstring text = x[0..x.strlen].idup;

-Steve

Re: Converting from C const(dchar*) to dstring

[Danyal Zia via Digitalmars-d-learn]

On Tuesday, 24 June 2014 at 17:59:41 UTC, Steven Schveighoffer 
wrote:

const(dchar *)x = ...;

// assuming 0 terminated
dstring text = x[0..x.strlen].idup;

-Steve

const(dchar)* x = Hello\0;
dstring text = x[0..x.strlen].idup;
writeln(text);

Error: no property 'strlen' for type 'const(dchar)*'

Re: Converting from C const(dchar*) to dstring

[Chris Cain via Digitalmars-d-learn]

On Tuesday, 24 June 2014 at 17:59:41 UTC, Steven Schveighoffer 
wrote:

// assuming 0 terminated
dstring text = x[0..x.strlen].idup;


strlen is only defined for char, not dchar:
https://github.com/D-Programming-Language/druntime/blob/master/src/core/stdc/string.d#L44

Re: Converting from C const(dchar*) to dstring

[Chris Cain via Digitalmars-d-learn]

On Tuesday, 24 June 2014 at 18:17:07 UTC, Danyal Zia wrote:
On Tuesday, 24 June 2014 at 17:59:41 UTC, Steven Schveighoffer 
wrote:

const(dchar *)x = ...;

// assuming 0 terminated
dstring text = x[0..x.strlen].idup;

-Steve

const(dchar)* x = Hello\0;
dstring text = x[0..x.strlen].idup;
writeln(text);

Error: no property 'strlen' for type 'const(dchar)*'


You can do what he said, but you'll have to write your own strlen 
function:


something like:

size_t strlen(in dchar* s) pure @system nothrow
{
size_t pos = 0;
dchar term = '\0';
while(s[pos] != term)
++pos;
return pos;
}
const(dchar)* ds = hello\0;
dstring text = ds[0..strlen(ds)].idup;
writeln(text);

works

Re: Converting from C const(dchar*) to dstring

[Justin Whear via Digitalmars-d-learn]

On Tue, 24 Jun 2014 18:17:06 +, Danyal Zia wrote:

 On Tuesday, 24 June 2014 at 17:59:41 UTC, Steven Schveighoffer wrote:
 const(dchar *)x = ...;

 // assuming 0 terminated dstring text = x[0..x.strlen].idup;

 -Steve
 const(dchar)* x = Hello\0;
 dstring text = x[0..x.strlen].idup;
 writeln(text);
 
 Error: no property 'strlen' for type 'const(dchar)*'

A dchar* strlen implementation: http://dpaste.dzfl.pl/a4053387d8a4

Re: Converting from C const(dchar*) to dstring

[Danyal Zia via Digitalmars-d-learn]

On Tuesday, 24 June 2014 at 18:34:31 UTC, Chris Cain wrote:
You can do what he said, but you'll have to write your own 
strlen function:


something like:

size_t strlen(in dchar* s) pure @system nothrow
{
size_t pos = 0;
dchar term = '\0';
while(s[pos] != term)
++pos;
return pos;
}
const(dchar)* ds = hello\0;
dstring text = ds[0..strlen(ds)].idup;
writeln(text);

works
It works indeed, thanks a lot! Any chance of making it into std 
phobos?

Re: Converting from C const(dchar*) to dstring

[Steven Schveighoffer via Digitalmars-d-learn]

On Tue, 24 Jun 2014 14:28:58 -0400, Chris Cain zsh...@gmail.com wrote:


On Tuesday, 24 June 2014 at 17:59:41 UTC, Steven Schveighoffer wrote:

// assuming 0 terminated
dstring text = x[0..x.strlen].idup;


strlen is only defined for char, not dchar:
https://github.com/D-Programming-Language/druntime/blob/master/src/core/stdc/string.d#L44



Right, I forgot about that.

-Steve