On Thu, Mar 10, 2022 at 05:39:34PM +0000, Chris Piker via Digitalmars-d-learn
wrote:
> Hi D
>
> There are quite a few string, array and range functions in phobos so
> I'm getting confused as to the right way to encode string data as
> UTF-8 directly into a stack buffer while keeping track of the write
> point.
>
> I have some output packets I'm building up in a tight loop. For speed
> I'm using the a priori knowledge that output packets will never be
> larger then 64K. So what's the best way to do this:
>
> ```d
> ubyte[65536] buf;
> ubyte[] usable_buf = buf;
>
> // part of some tight loop, how to create function writef_utf8 ?
> foreach(input_thing; things){
> usable_buf.writef_utf8!"format str"(input_thing.fieldA,
> input_thing.fieldB);
> }
>
> size_t used = buf.length - usable_buf.length;
> stdout.write(buf[0.. used]);
>
> ```
Probably what you're looking for is std.format.formattedWrite. For
example:
------
import std;
void main() {
ubyte[65536] buf;
char[] usable_buf = cast(char[]) buf[];
usable_buf.formattedWrite!"Blah %d blah %s"(123, "Это UTF-8 строка.");
auto used = buf.length - usable_buf.length;
writefln("%(%02X %)", buf[0 .. used]);
}
------
D strings are UTF-8 by default, so for the most part, you don't need to
worry about it.
T
--
Guns don't kill people. Bullets do.
