George Ionescu wrote:
Hello SQLite users,
Hello Dr. Hipp,
I would like to implement my own RegExp functions (to limit results based on conditions). From my understanding, sqlite_create_function cannot be used for this (the function can only return a value; it cannot tell sqlite not to return a row). What is the approach you would recommend?
Regards,
George Ionescu
I have done just this.. relevant code below (It's C in a C++ project, messy and relatively
inefficient but it works a treat).
The killer bit is in the open database routine where it creates the user define function.
/*
* Functions to patch a regex search into sqlite
*/
int sqliteRlikeCompare(const char *zPattern, const char *zString, sqregex *reg){
int res;
if (reg-regex_raw == NULL || (strcmp (zPattern, reg-regex_raw) != 0)){
if (reg-regex_raw != NULL) {
free(reg-regex_raw);
regfree(reg-regex_c);
}
reg-regex_raw = (char *)malloc(strlen(zPattern)+1);
strncpy(reg-regex_raw, zPattern, strlen(zPattern)+1);
res = regcomp(reg-regex_c, zPattern, REG_EXTENDED);
if ( res != 0 ) {
printf(Regcomp failed with code %u on string %s\n,res,zPattern);
free(reg-regex_raw);
reg-regex_raw=NULL;
return 0;
}
}
res = (regexec(reg-regex_c, zString, 0, NULL, 0)==0);
return res;
}
void rlikeFunc(sqlite_func *context, int arg, const char **argv){
if( argv[0]==0 || argv[1]==0 ){
printf(One of arguments Null!!\n);
return;
}
sqlite_set_result_int(context,
sqliteRlikeCompare((const char*)argv[0],
(const char*)argv[1], (sqregex *)sqlite_user_data(context) ));
}
/*
* try to open a db specified via setUrl
* and options
*/
bool OSQLiteDriver::open() {
char *error;
qDebug(OSQLiteDriver::open: about to open);
m_sqlite = sqlite_open(m_url.local8Bit(),
0,
error );
/* failed to open */
if (m_sqlite == 0l ) {
// FIXME set the last error
qWarning(OSQLiteDriver::open: %s, error );
free( error );
return false;
}
if (sqlite_create_function(m_sqlite,rlike,2,rlikeFunc,sqreg) != 0)
odebug Unable to create user defined function! oendl;
if (sqlite_function_type(m_sqlite,rlike,SQLITE_NUMERIC) != 0)
odebug Unable to set rlike function result type! oendl;
sqreg.regex_raw = NULL;
return true;
}
Regards,
Brad
-
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
