updates to ip_to_str[_buf]() to make them faster.

This functin was in a recent profiling run the fifth most expensive function.
It consumed ~3.5% of the total cpu in that run.

Using a static table this function is now just over twice as fast as previously.

My testrun calling it 10.000.000 times in a loop changed the execution time from ~17.3s ro ~8.2s

If this test was representative for the speedup and if ~3.5 in the profile run
was representative for normal cases this should make ethereal ~1.8% faster.
Woohoo.
(low hanging fruit)

svn path=/trunk/; revision=8992
This commit is contained in:
Ronnie Sahlberg 2003-11-17 22:56:45 +00:00
parent 7952d0627a
commit 8acd679327
1 changed files with 79 additions and 39 deletions

View File

@ -1,7 +1,7 @@
/* to_str.c
* Routines for utilities to convert various other types to strings.
*
* $Id: to_str.c,v 1.38 2003/10/07 21:15:00 guy Exp $
* $Id: to_str.c,v 1.39 2003/11/17 22:56:45 sahlberg Exp $
*
* Ethereal - Network traffic analyzer
* By Gerald Combs <gerald@ethereal.com>
@ -132,58 +132,98 @@ ether_to_str(const guint8 *ad)
return bytestring_to_str(ad, 6, ':');
}
/* XXX FIXME
remove this one later when every call has been converted to address_to_str()
/*
This function is very fast and this function is called a lot.
XXX update the address_to_str stuff to use this function.
*/
gchar *
ip_to_str(const guint8 *ad) {
static gchar str[4][16];
static gchar *cur;
static int cur_idx=0;
gchar *cur;
if (cur == &str[0][0]) {
cur = &str[1][0];
} else if (cur == &str[1][0]) {
cur = &str[2][0];
} else if (cur == &str[2][0]) {
cur = &str[3][0];
} else {
cur = &str[0][0];
cur_idx++;
if(cur_idx>3){
cur_idx=0;
}
cur=&str[cur_idx][0];
ip_to_str_buf(ad, cur);
return cur;
}
/*
This function is very fast and this function is called a lot.
XXX update the address_to_str stuff to use this function.
*/
static const char * const fast_strings[] = {
"0", "1", "2", "3", "4", "5", "6", "7",
"8", "9", "10", "11", "12", "13", "14", "15",
"16", "17", "18", "19", "20", "21", "22", "23",
"24", "25", "26", "27", "28", "29", "30", "31",
"32", "33", "34", "35", "36", "37", "38", "39",
"40", "41", "42", "43", "44", "45", "46", "47",
"48", "49", "50", "51", "52", "53", "54", "55",
"56", "57", "58", "59", "60", "61", "62", "63",
"64", "65", "66", "67", "68", "69", "70", "71",
"72", "73", "74", "75", "76", "77", "78", "79",
"80", "81", "82", "83", "84", "85", "86", "87",
"88", "89", "90", "91", "92", "93", "94", "95",
"96", "97", "98", "99", "100", "101", "102", "103",
"104", "105", "106", "107", "108", "109", "110", "111",
"112", "113", "114", "115", "116", "117", "118", "119",
"120", "121", "122", "123", "124", "125", "126", "127",
"128", "129", "130", "131", "132", "133", "134", "135",
"136", "137", "138", "139", "140", "141", "142", "143",
"144", "145", "146", "147", "148", "149", "150", "151",
"152", "153", "154", "155", "156", "157", "158", "159",
"160", "161", "162", "163", "164", "165", "166", "167",
"168", "169", "170", "171", "172", "173", "174", "175",
"176", "177", "178", "179", "180", "181", "182", "183",
"184", "185", "186", "187", "188", "189", "190", "191",
"192", "193", "194", "195", "196", "197", "198", "199",
"200", "201", "202", "203", "204", "205", "206", "207",
"208", "209", "210", "211", "212", "213", "214", "215",
"216", "217", "218", "219", "220", "221", "222", "223",
"224", "225", "226", "227", "228", "229", "230", "231",
"232", "233", "234", "235", "236", "237", "238", "239",
"240", "241", "242", "243", "244", "245", "246", "247",
"248", "249", "250", "251", "252", "253", "254", "255"
};
void
ip_to_str_buf(const guint8 *ad, gchar *buf)
{
gchar *p;
int i;
guint32 octet;
guint32 digit;
gboolean saw_nonzero;
register gchar const *p;
register gchar *b=buf;
register gchar c;
p = buf;
i = 0;
for (;;) {
saw_nonzero = FALSE;
octet = ad[i];
digit = octet/100;
if (digit != 0) {
*p++ = digit + '0';
saw_nonzero = TRUE;
}
octet %= 100;
digit = octet/10;
if (saw_nonzero || digit != 0)
*p++ = digit + '0';
digit = octet%10;
*p++ = digit + '0';
if (i == 3)
break;
*p++ = '.';
i++;
}
*p = '\0';
p=fast_strings[*ad++];
while((c=*p)){
*b++=c;
p++;
}
*b++='.';
p=fast_strings[*ad++];
while((c=*p)){
*b++=c;
p++;
}
*b++='.';
p=fast_strings[*ad++];
while((c=*p)){
*b++=c;
p++;
}
*b++='.';
p=fast_strings[*ad++];
while((c=*p)){
*b++=c;
p++;
}
*b=0;
}