Re: Can you shrink it further?

[Stefan Koch via Digitalmars-d]

On Tuesday, 11 October 2016 at 02:48:22 UTC, Andrei Alexandrescu 
wrote:
That looks good. I'm just worried about the jump forward - 
ideally the case c < 127 would simply entail a quick return. I 
tried a fix, but it didn't do what I wanted in ldc. We 
shouldn't assert(0) if wrong - just skip one byte. Also, are we 
right to not worry about 5- and 6-byte sequences? The docs keep 
on threatening with it, and then immediately mention those are 
not valid.

[ ... ]
Andrei


If you want to skip a byte it's easy to do as well.

void popFront3(ref char[] s) @trusted pure nothrow {
   immutable c = s[0];
   uint char_length = 1;
   if (c < 127)
   {
   Lend :
     s = s.ptr[char_length .. s.length];
   } else {
     if ((c & b01100_0000) == 0b1000_0000)
     {
       //just skip one in case this is not the beginning of a 
code-point char
       goto Lend;
     }
     if (c < 192)
     {
       char_length = 2;
       goto Lend;
     }
     if (c < 240)
     {
       char_length = 3;
       goto Lend;
     }
     if (c < 248)
     {
       char_length = 4;
       goto Lend;
     }
   }
 }