+1 (concept)
> On Nov 24, 2015, at 12:40 PM, William A Rowe Jr <wr...@rowe-clan.net> wrote:
>
> On Tue, Nov 24, 2015 at 10:18 AM, Graham Leggett <minf...@sharp.fm> wrote:
> On 24 Nov 2015, at 6:15 PM, Yann Ylavic <ylavic....@gmail.com> wrote:
>
> > Not sure:
> > if (!strcmp(h, "max-age")
> > || ap_cmpcasestr(h, "max-age"))
> > is likely to be a bit faster than a single ap_cmpcasestr() when it
> > matches, but much slower when it does not.
>
> Yep, that’s the point.
>
> The vast majority of comparisons are lowercase for tokens like this. Might as
> well test that fast path first before testing the worst case scenario.
>
> Hmmm, it's our implementation, why increase the pain? Consider the following
> 'optimization' - fallthrough from identity to case insensitivity with one
> wasted equality test...
>
> AP_DECLARE(int) ap_casecmpstr(const char *s1, const char *s2)
> {
> const unsigned char *ps1 = (const unsigned char *) s1;
> const unsigned char *ps2 = (const unsigned char *) s2;
>
> while (*ps1 == *ps2) {
> if (*ps1++ == '\0') {
> return (0);
> }
> ps2++;
> }
> while (ucharmap[*ps1] == ucharmap[*ps2]) {
> if (*ps1++ == '\0') {
> return (0);
> }
> ps2++;
> }
> return (ucharmap[*ps1] - ucharmap[*ps2]);
> }
>
>
> AP_DECLARE(int) ap_casecmpstrn(const char *s1, const char *s2, apr_size_t n)
> {
> const unsigned char *ps1 = (const unsigned char *) s1;
> const unsigned char *ps2 = (const unsigned char *) s2;
> while (n) {
> if (*ps1 != *ps2) {
> break;
> }
> if (*ps1++ == '\0') {
> return (0);
> }
> ps2++;
> n--;
> }
> while (n--) {
> if (ucharmap[*ps1] != ucharmap[*ps2]) {
> return (ucharmap[*ps1] - ucharmap[*ps2]);
> }
> if (*ps1++ == '\0') {
> break;
> }
> ps2++;
> }
> return (0);
> }
>
>
