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Overview
| Comment: | Improve the performance of the built-in REPLACE() function in cases where it does many substitutions that make the string larger. OSSFuzz is reporting intermittant timeouts when running a test where it does a REPLACE() on a 930KB random blob. Perhaps this enhancement will fix that. |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA3-256: |
fab2c2b07b5d3cd851db3e6f5c8a4415 |
| User & Date: | drh 2018-02-09 23:25:14.764 |
Context
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2018-02-10
| ||
| 02:31 | Fix misplaced testcase() macros from the previous check-in. (check-in: 3aed949a18 user: drh tags: trunk) | |
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2018-02-09
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| 23:25 | Improve the performance of the built-in REPLACE() function in cases where it does many substitutions that make the string larger. OSSFuzz is reporting intermittant timeouts when running a test where it does a REPLACE() on a 930KB random blob. Perhaps this enhancement will fix that. (check-in: fab2c2b07b user: drh tags: trunk) | |
| 20:49 | Add the zorder.c extension implementing zorder() and unzorder() SQL functions. (check-in: a57a77dc0c user: drh tags: trunk) | |
Changes
Changes to src/func.c.
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1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 | unsigned char *zOut; /* The output */ int nStr; /* Size of zStr */ int nPattern; /* Size of zPattern */ int nRep; /* Size of zRep */ i64 nOut; /* Maximum size of zOut */ int loopLimit; /* Last zStr[] that might match zPattern[] */ int i, j; /* Loop counters */ assert( argc==3 ); UNUSED_PARAMETER(argc); zStr = sqlite3_value_text(argv[0]); if( zStr==0 ) return; nStr = sqlite3_value_bytes(argv[0]); assert( zStr==sqlite3_value_text(argv[0]) ); /* No encoding change */ | > > | 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 | unsigned char *zOut; /* The output */ int nStr; /* Size of zStr */ int nPattern; /* Size of zPattern */ int nRep; /* Size of zRep */ i64 nOut; /* Maximum size of zOut */ int loopLimit; /* Last zStr[] that might match zPattern[] */ int i, j; /* Loop counters */ unsigned cntExpand; /* Number zOut expansions */ sqlite3 *db = sqlite3_context_db_handle(context); assert( argc==3 ); UNUSED_PARAMETER(argc); zStr = sqlite3_value_text(argv[0]); if( zStr==0 ) return; nStr = sqlite3_value_bytes(argv[0]); assert( zStr==sqlite3_value_text(argv[0]) ); /* No encoding change */ |
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1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 |
nOut = nStr + 1;
assert( nOut<SQLITE_MAX_LENGTH );
zOut = contextMalloc(context, (i64)nOut);
if( zOut==0 ){
return;
}
loopLimit = nStr - nPattern;
for(i=j=0; i<=loopLimit; i++){
if( zStr[i]!=zPattern[0] || memcmp(&zStr[i], zPattern, nPattern) ){
zOut[j++] = zStr[i];
}else{
| > < | | < < | | | | | > > > > > > > | | | | | | > > | | 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 |
nOut = nStr + 1;
assert( nOut<SQLITE_MAX_LENGTH );
zOut = contextMalloc(context, (i64)nOut);
if( zOut==0 ){
return;
}
loopLimit = nStr - nPattern;
cntExpand = 0;
for(i=j=0; i<=loopLimit; i++){
if( zStr[i]!=zPattern[0] || memcmp(&zStr[i], zPattern, nPattern) ){
zOut[j++] = zStr[i];
}else{
if( nRep>nPattern ){
nOut += nRep - nPattern;
if( nOut-1>db->aLimit[SQLITE_LIMIT_LENGTH] ){
sqlite3_result_error_toobig(context);
sqlite3_free(zOut);
return;
}
testcase( nOut-1==db->aLimit[SQLITE_LIMIT_LENGTH] );
testcase( nOut-2==db->aLimit[SQLITE_LIMIT_LENGTH] );
cntExpand++;
if( (cntExpand&(cntExpand-1))==0 ){
/* Grow the size of the output buffer only on substitutions
** whose index is a power of two: 1, 2, 4, 8, 16, 32, ... */
u8 *zOld;
zOld = zOut;
zOut = sqlite3_realloc64(zOut, (int)nOut + (nOut - nStr - 1));
if( zOut==0 ){
sqlite3_result_error_nomem(context);
sqlite3_free(zOld);
return;
}
}
}
memcpy(&zOut[j], zRep, nRep);
j += nRep;
i += nPattern-1;
}
}
assert( j+nStr-i+1<=nOut );
memcpy(&zOut[j], &zStr[i], nStr-i);
j += nStr - i;
assert( j<=nOut );
zOut[j] = 0;
sqlite3_result_text(context, (char*)zOut, j, sqlite3_free);
}
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Changes to test/func.test.
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503 504 505 506 507 508 509 510 511 512 513 514 515 516 |
do_test func-9.12-utf8 {
execsql {SELECT hex(replace('abcdefg','','12'))}
} {61626364656667}
do_test func-9.13-utf8 {
execsql {SELECT hex(replace('aabcdefg','a','aaa'))}
} {616161616161626364656667}
}
# Use the "sqlite_register_test_function" TCL command which is part of
# the text fixture in order to verify correct operation of some of
# the user-defined SQL function APIs that are not used by the built-in
# functions.
#
set ::DB [sqlite3_connection_pointer db]
| > > > > > > > > > > > | 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 |
do_test func-9.12-utf8 {
execsql {SELECT hex(replace('abcdefg','','12'))}
} {61626364656667}
do_test func-9.13-utf8 {
execsql {SELECT hex(replace('aabcdefg','a','aaa'))}
} {616161616161626364656667}
}
do_execsql_test func-9.14 {
WITH RECURSIVE c(x) AS (
VALUES(1)
UNION ALL
SELECT x+1 FROM c WHERE x<1040
)
SELECT
count(*),
sum(length(replace(printf('abc%.*cxyz',x,'m'),'m','nnnn'))-(6+x*4))
FROM c;
} {1040 0}
# Use the "sqlite_register_test_function" TCL command which is part of
# the text fixture in order to verify correct operation of some of
# the user-defined SQL function APIs that are not used by the built-in
# functions.
#
set ::DB [sqlite3_connection_pointer db]
|
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