I suspect the question was asked somewhere before.
If so just give a link.

Anyway:

class IoContext {
    ...
    ubyte[] buf;
    ...
    this(uint bufSize) {
        buf = new ubyte[bufSize];
    }
}

The buffer contains (ascii) string terminated with '\n'.
In order to print it not as an array of numbers (buf is 1024 bytes long),
but as usual string I do

char[] s = cast(char[])ioCtx.buf[0 .. strlen(cast(char*)ioCtx.buf.ptr) - 1];
// -1 is to eliminate terminating '\n'
writefln("got '%s' from '%s:%d'", s, client.addr, client.port);

Is there some more concise/elegant way to do that?

Of course, I could use old good printf() instead:

printf(
    "got '%s' from '%s:%d'\n",
    ioCtx.buf.ptr,            // '\n' still there
    toStringz(client.addr),
    client.port
);

but I want to use D stdlib, not libc.

On Thursday, 30 December 2021 at 09:34:27 UTC, eugene wrote:

Few years ago i asked a similar question, not to do UTF-8 but to do Ascii. I was working on a tool for Morrowind after determining the strings were not variable in length and instead much like ascii fixed at 256 combinations.

The answer i ended up with was a quick conversion to a UTF in order to print it. Seems you might have to convert to Latin-1.

Here's the old thread.

https://forum.dlang.org/thread/lehgyzmwewgvkdgraizv@forum.dlang.org

On Thursday, 30 December 2021 at 16:00:59 UTC, Era Scarecrow wrote:

For a moment I only have symbols from the lower half of ASCII table.
I meant - can that be done as simple as in C, i.e:

u8 *buf;
...
printf("%s", (char*)buf);

without any twists and turns.

On Thursday, 30 December 2021 at 09:34:27 UTC, eugene wrote:

class IoContext {
    ...
    ubyte[] buf;
    ...
    this(uint bufSize) {
        buf = new ubyte[bufSize];
    }
}

class IoContext {
     ...
     ubyte[] buf;
     ...
     this(uint bufSize) {
         buf.length = bufSize; //this should do the same thing, I believe
     }
}

char[] s = cast(char[])ioCtx.buf[0 .. strlen(cast(char*)ioCtx.buf.ptr) - 1];
// -1 is to eliminate terminating '\n'
writefln("got '%s' from '%s:%d'", s, client.addr, client.port);

char[] s = cast(char[])ioCtx.buf[0 .. $];// please remember that in `[0 .. $]` last index is automatically `length - 1` but just buf[$] will be an error since there the actual `length` will be used

I think the above code is correct, please verify

On Thursday, 30 December 2021 at 09:34:27 UTC, eugene wrote:

char[] s = cast(char[])ioCtx.buf[0 .. strlen(cast(char*)ioCtx.buf.ptr) - 1];
// -1 is to eliminate terminating '\n'
writefln("got '%s' from '%s:%d'", s, client.addr, client.port);

char[] s = fromStringz(cast(char*)ioCtx.buf.ptr).strip;
writefln("got '%s' from '%s:%d'", s, client.addr, client.port);

Well, this will do:)

On Thursday, 30 December 2021 at 16:49:17 UTC, Tejas wrote:

char[] s = cast(char[])ioCtx.buf[0 .. $];// please remember that in `[0 .. $]` last index is automatically `length - 1` but just buf[$] will be an error since there the actual `length` will be used

There is one pecularity:

char[] s = fromStringz(cast(char*)ioCtx.buf.ptr);
writefln("got '%s' from '%s:%d'", s.strip, client.addr, client.port);
// strip works :)

char[] s = cast(char[])ioCtx.buf[0 .. $];
writefln("got '%s' from '%s:%d'", s.strip, client.addr, client.port);
// strip does not work :(

On Thursday, 30 December 2021 at 17:07:20 UTC, eugene wrote:

char[] s = cast(char[])ioCtx.buf[0 .. $];// please remember that in `[0 .. $]` last index is automatically `length - 1` but just buf[$] will be an error since there the actual `length` will be used

char[] s = fromStringz(cast(char*)ioCtx.buf.ptr);
writefln("got '%s' from '%s:%d'", s.strip, client.addr, client.port);
// strip works :)

char[] s = cast(char[])ioCtx.buf[0 .. $];
writefln("got '%s' from '%s:%d'", s.strip, client.addr, client.port);
// strip does not work :(

I'll need to know the error message, because the following works:

import std;
void main()
{
    ubyte[] c ;
    c.length = 100;
    char[] arr = cast(char[])c[0 .. $];
    foreach(ref elem; arr)
        elem = 'a';
    writeln(arr.strip);
}

On Thursday, 30 December 2021 at 16:49:17 UTC, Tejas wrote:

Self-contained example:

import std.stdio;
import std.string;

void main() {
    ubyte[8] b = [0x68, 0x65, 0x6C, 0x6C, 0x6F, 0x0A, 0x00, 0x00];
    /* "hello\n\0\0" */

    char[] s = fromStringz(cast(char*)b.ptr);
    writefln("'%s, world'", s.strip);

    s = cast(char[])b[0 .. $];
    writefln("'%s, world'", s.strip);
}

Output:

@mono:~/2-coding/d-lang/misc$ ./p
'hello, world'
'hello
, world'

On Thursday, 30 December 2021 at 17:16:10 UTC, Tejas wrote:

There is none, see example in my prev message

import std;
void main()
{
    ubyte[] c ;
    c.length = 100;
    char[] arr = cast(char[])c[0 .. $];
    foreach(ref elem; arr)
        elem = 'a';
    writeln(arr.strip);
}

There is nothing to strip here (spaces, new lines...).

On Thursday, 30 December 2021 at 17:31:27 UTC, eugene wrote:

import std.stdio;
import std.string;

void main() {
    ubyte[8] b = [0x68, 0x65, 0x6C, 0x6C, 0x6F, 0x0A, 0x00, 0x00];
    /* "hello\n\0\0" */

    char[] s = fromStringz(cast(char*)b.ptr);
    writefln("'%s, world'", s.strip);

    s = cast(char[])b[0 .. $];
    writefln("'%s, world'", s.strip);
}

@mono:~/2-coding/d-lang/misc$ ./p
'hello, world'
'hello
, world'

I'm not at my computer anymore, could you please replace the 0x00 with 0x0A and tell me if strip still doesn't work for my solution?

I think the fromstringz is trimming the null bytes for you, making the \n the last character, allowing strip to work.