I tested this change with both Jim's and my versions, that's slower.
The better implementation I have so far is:
int ap_casecmpstr_2(const char *s1, const char *s2)
{
size_t i;
const unsigned char *ps1 = (const unsigned char *) s1;
const unsigned char *ps2 = (const unsigned char *) s2;
for (i = 0; ; ++i) {
const int c1 = ucharmap[ps1[i]];
const int c2 = ucharmap[ps2[i]];
if (c1 != c2) {
return c1 - c2;
}
if (!c1) {
break;
}
}
return (0);
}
which is ~15% faster than the current one (and not 50% unless I remove
the translation :)
I also tried:
for (i = 0; ; ++i) {
const int c1 = ps1[i];
const int c2 = ps2[i];
if (c1 != c2 && ucharmap[c1] != ucharmap[c2]) {
return ucharmap[c1] - ucharmap[c2];
}
...
but no.
On Tue, Nov 24, 2015 at 7:56 PM, William A Rowe Jr <[email protected]> wrote:
> For the optimization cases Graham was proposing, how does this perform on
> your test setup? Looking for both absmatches, case mismatches and proper vs
> lowercase comparisons...
>
> int ap_casecmpstr_2(const char *s1, const char *s2)
> {
> size_t i;
> const unsigned char *ps1 = (const unsigned char *) s1;
> const unsigned char *ps2 = (const unsigned char *) s2;
>
> for (i = 0; ; ++i) {
> const int c1 = ucharmap[ps1[i]];
> const int c2 = ucharmap[ps2[i]];
> /* Above lookups are optimized away if first test below succeeds */
>
> if ((ps1[i] != ps2[i]) && (c1 != c2)) {
> return c1 - c2;
> }
> if (!c1) {
> break;
> }
> }
> return (0);
> }
>
>
> On Tue, Nov 24, 2015 at 12:43 PM, Yann Ylavic <[email protected]> wrote:
>>
>> On Tue, Nov 24, 2015 at 7:39 PM, Mikhail T. <[email protected]>
>> wrote:
>> > On 24.11.2015 13:04, Yann Ylavic wrote:
>> >
>> > int ap_casecmpstr_2(const char *s1, const char *s2)
>> > {
>> > size_t i;
>> > const unsigned char *ps1 = (const unsigned char *) s1;
>> > const unsigned char *ps2 = (const unsigned char *) s2;
>> >
>> > for (i = 0; ; ++i) {
>> > const int c1 = ps1[i];
>> > const int c2 = ps2[i];
>> >
>> > if (c1 != c2) {
>> > return c1 - c2;
>> > }
>> > if (!c1) {
>> > break;
>> > }
>> > }
>> > return (0);
>> > }
>> >
>> > Sorry, but would not the above declare "A" and "a" to be different?
>>
>> Yeah, forgot the translation, I went too fast :)
>
>
