[Asterisk-Dev] FW: asterisk/doc CODING-GUIDELINES,1.4,1.5

[Paul Cadach]

Hello,

Andrew Kohlsmith wrote:

[skip]

> int count = 0;
> while (*(string++))
>         count++;
>
> Yes my C's getting rusty but can you think of a better/faster way to count the
> characters in a zero-terminated string?

int strlen(register char *str)
{
  register char *str1 = str;
  while(*(str1++));
  return(str1 - str - 1);
}

Just single increment within the loop (expression str1 - str - 1 have constant execution time, usually sub <reg>,<reg>
and dec <reg>, instead of count++ within loop body). Compiler's internal implementation of strlen() (when used with
key -O2 or higher) is always better than hand-written.


WBR,
Paul.