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dupecheck: Further optimize CPU use, skip some unnecessary scans 

Only scan regular packets without DELs or low bytes once.
This commit is contained in:
Heikki Hannikainen 2022-10-30 20:35:11 +02:00
parent eb2c199a66
commit 43dd2bf16e
1 changed files with 57 additions and 47 deletions
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104
src/dupecheck.c
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@ -401,11 +401,8 @@ static int dupecheck_mangle_store(const char *addr, int addrlen, const char *dat
int tlen1, tlen2, tlen3;
int i;
char c;
/* TODO: dupecheck_mangle_store: Check for the necessity to do
* any futher packet scans when doing the initial scan
* (check for 8-bit / low data => optimize /shortcut)
*/
int have_del = 0;
int have_low_values = 0;
ilen = addrlen + datalen;
@ -420,15 +417,13 @@ static int dupecheck_mangle_store(const char *addr, int addrlen, const char *dat
/********************************************/
/* remove spaces from the end of the packet */
// TODO: unnecessary tb1, we can just use ib for this. Skip the memcpy.
memcpy(tb1, ib, ilen);
tlen1 = ilen;
while (tlen1 > 0 && tb1[tlen1-1] == ' ')
while (tlen1 > 0 && ib[tlen1-1] == ' ')
--tlen1;
if (tlen1 != ilen) {
//hlog(LOG_DEBUG, "dupecheck_mangle_store: removed %d spaces: '%.*s'", ilen-tlen1, tlen1, tb1);
dupecheck_add_buf(tb1, tlen1, DTYPE_SPACE_TRIM);
dupecheck_add_buf(ib, tlen1, DTYPE_SPACE_TRIM);
}
/*************************/
@ -436,10 +431,21 @@ static int dupecheck_mangle_store(const char *addr, int addrlen, const char *dat
* tb2: 8th bit is cleared
* tb3: 8th bit replaced with a space
*/
// TODO: Check for DELs and low bytes in this loop, and skip those steps if none are found.
/* Check for the necessity to do
* any futher packet scans when doing the initial scan
* (check for DEL bytes / low data => optimize /shortcut)
*/
tlen1 = tlen2 = tlen3 = 0;
for (i = 0; i < ilen; i++) {
c = ib[i] & 0x7F;
c = ib[i];
if (c == 0x7F)
have_del = 1;
if (c < 0x20 && c > 0)
have_low_values = 1;
c = c & 0x7F;
tb2[tlen2++] = c;
if (ib[i] != c) {
/* high bit is on */
@ -464,50 +470,54 @@ static int dupecheck_mangle_store(const char *addr, int addrlen, const char *dat
* tb1: Low data (0 <= x < 0x20 deleted
* tb2: Low data replaced with spaces
*/
tlen1 = tlen2 = 0;
for (i = 0; i < ilen; i++) {
c = ib[i];
if (c < 0x20 && c > 0) {
/* low data, tb2 gets a space and tb1 gets nothing */
tb2[tlen2++] = ' ';
} else {
/* regular stuff */
tb1[tlen1++] = c;
tb2[tlen2++] = c;
if (have_low_values) {
tlen1 = tlen2 = 0;
for (i = 0; i < ilen; i++) {
c = ib[i];
if (c < 0x20 && c > 0) {
/* low data, tb2 gets a space and tb1 gets nothing */
tb2[tlen2++] = ' ';
} else {
/* regular stuff */
tb1[tlen1++] = c;
tb2[tlen2++] = c;
}
}
if (tlen1 != ilen) {
/* if there was low data, store it */
//hlog(LOG_DEBUG, "dupecheck_mangle_store: removed %d low chars: '%.*s'", ilen-tlen1, tlen1, tb1);
//hlog(LOG_DEBUG, "dupecheck_mangle_store: replaced %d low chars: '%.*s'", ilen-tlen1, tlen2, tb2);
dupecheck_add_buf(tb1, tlen1, DTYPE_LOWDATA_STRIP);
dupecheck_add_buf(tb2, tlen2, DTYPE_LOWDATA_SPACED);
}
}
if (tlen1 != ilen) {
/* if there was low data, store it */
//hlog(LOG_DEBUG, "dupecheck_mangle_store: removed %d low chars: '%.*s'", ilen-tlen1, tlen1, tb1);
//hlog(LOG_DEBUG, "dupecheck_mangle_store: replaced %d low chars: '%.*s'", ilen-tlen1, tlen2, tb2);
dupecheck_add_buf(tb1, tlen1, DTYPE_LOWDATA_STRIP);
dupecheck_add_buf(tb2, tlen2, DTYPE_LOWDATA_SPACED);
}
/**********************************************
* tb1: Del characters (0x7f) deleted
* tb2: Del characters replaced with spaces
*/
tlen1 = tlen2 = 0;
for (i = 0; i < ilen; i++) {
c = ib[i];
if (c == 0x7f) {
/* low data, tb2 gets a space and tb1 gets nothing */
tb2[tlen2++] = ' ';
} else {
/* regular stuff */
tb1[tlen1++] = c;
tb2[tlen2++] = c;
if (have_del) {
tlen1 = tlen2 = 0;
for (i = 0; i < ilen; i++) {
c = ib[i];
if (c == 0x7f) {
/* low data, tb2 gets a space and tb1 gets nothing */
tb2[tlen2++] = ' ';
} else {
/* regular stuff */
tb1[tlen1++] = c;
tb2[tlen2++] = c;
}
}
if (tlen1 != ilen) {
/* if there was low data, store it */
//hlog(LOG_DEBUG, "dupecheck_mangle_store: removed %d low chars: '%.*s'", ilen-tlen1, tlen1, tb1);
//hlog(LOG_DEBUG, "dupecheck_mangle_store: replaced %d low chars: '%.*s'", ilen-tlen1, tlen2, tb2);
dupecheck_add_buf(tb1, tlen1, DTYPE_DEL_STRIP);
dupecheck_add_buf(tb2, tlen2, DTYPE_DEL_SPACED);
}
}
if (tlen1 != ilen) {
/* if there was low data, store it */
//hlog(LOG_DEBUG, "dupecheck_mangle_store: removed %d low chars: '%.*s'", ilen-tlen1, tlen1, tb1);
//hlog(LOG_DEBUG, "dupecheck_mangle_store: replaced %d low chars: '%.*s'", ilen-tlen1, tlen2, tb2);
dupecheck_add_buf(tb1, tlen1, DTYPE_DEL_STRIP);
dupecheck_add_buf(tb2, tlen2, DTYPE_DEL_SPACED);
}
return 0;