add RainerScript re_extract() function

4 files changed, 114 insertions, 2 deletions

diff --git a/ChangeLog b/ChangeLog
index 01ba0f45..54aacf0c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,6 @@
 ---------------------------------------------------------------------------
 Version 7.3.10  [devel] 2013-04-??
+- added RainerScript re_extract() function
 - bugfix: imuxsock aborted under some conditions
   regression from ratelimiting enhancements
 ---------------------------------------------------------------------------
diff --git a/doc/rainerscript.html b/doc/rainerscript.html
index d76316ed..7cbbfa9f 100644
--- a/doc/rainerscript.html
+++ b/doc/rainerscript.html
@@ -66,6 +66,15 @@ variable, if it exists. Returns an empty string if it does not exist.
 <li>cstr(expr) - converts expr to a string value
 <li>cnum(expr) - converts expr to a number (integer)
 <li>re_match(expr, re) - returns 1, if expr matches re, 0 otherwise
+<li>re_extract(expr, re, match, submatch, no-found) - extracts
+data from a string (property) via a regular expression match.
+POSIX ERE regular expressions are used. The variable "match" contains
+the number of the match to use. This permits to pick up more than the
+first expression match. Submatch is the submatch to match (max 50 supported).
+The "no-found" parameter specifies which string is to be returned in case when
+the regular expression is not found. Note that match and submatch start with
+zero. It currently is not possible to extract more than one submatch with
+a single call.
 <li>field(str, delim, matchnbr) - returns a field-based substring. str is the string
 to search, delim is the delimiter and matchnbr is the match to search
 for (the first match starts at 1). This works similar as the field based
diff --git a/grammar/rainerscript.c b/grammar/rainerscript.c
index 8ef7429d..00e1e835 100644
--- a/grammar/rainerscript.c
+++ b/grammar/rainerscript.c
@@ -1228,6 +1228,96 @@ finalize_it:
 	RETiRet;
 }
 
+static inline void
+doFunc_re_extract(struct cnffunc *func, struct var *ret, void* usrptr)
+{
+	size_t submatchnbr;
+	short matchnbr;
+	regmatch_t pmatch[50];
+	int bMustFree;
+	es_str_t *estr;
+	char *str;
+	struct var r[CNFFUNC_MAX_ARGS];
+	int iLenBuf;
+	unsigned iOffs;
+	short iTry = 0;
+	uchar bFound = 0;
+	iOffs = 0;
+	sbool bHadNoMatch = 0;
+
+	cnfexprEval(func->expr[0], &r[0], usrptr);
+	/* search string is already part of the compiled regex, so we don't
+	 * need it here!
+	 */
+	cnfexprEval(func->expr[2], &r[2], usrptr);
+	cnfexprEval(func->expr[3], &r[3], usrptr);
+	str = (char*) var2CString(&r[0], &bMustFree);
+	matchnbr = (short) var2Number(&r[2], NULL);
+	submatchnbr = (size_t) var2Number(&r[3], NULL);
+	if(submatchnbr > sizeof(pmatch)/sizeof(regmatch_t)) {
+		DBGPRINTF("re_extract() submatch %d is too large\n", submatchnbr);
+		bHadNoMatch = 1;
+		goto finalize_it;
+	}
+
+	/* first see if we find a match, iterating through the series of
+	 * potential matches over the string.
+	 */
+	while(!bFound) {
+		int iREstat;
+		iREstat = regexp.regexec(func->funcdata, (char*)(str + iOffs),
+					 submatchnbr+1, pmatch, 0);
+		dbgprintf("re_extract: regexec return is %d\n", iREstat);
+		if(iREstat == 0) {
+			if(pmatch[0].rm_so == -1) {
+				dbgprintf("oops ... start offset of successful regexec is -1\n");
+				break;
+			}
+			if(iTry == matchnbr) {
+				bFound = 1;
+			} else {
+				dbgprintf("re_extract: regex found at offset %d, new offset %d, tries %d\n",
+					  iOffs, (int) (iOffs + pmatch[0].rm_eo), iTry);
+				iOffs += pmatch[0].rm_eo;
+				++iTry;
+			}
+		} else {
+			break;
+		}
+	}
+	dbgprintf("re_extract: regex: end search, found %d\n", bFound);
+	if(!bFound) {
+		bHadNoMatch = 1;
+		goto finalize_it;
+	} else {
+		/* Match- but did it match the one we wanted? */
+		/* we got no match! */
+		if(pmatch[submatchnbr].rm_so == -1) {
+			bHadNoMatch = 1;
+			goto finalize_it;
+		}
+		/* OK, we have a usable match - we now need to malloc pB */
+		iLenBuf = pmatch[submatchnbr].rm_eo - pmatch[submatchnbr].rm_so;
+		estr = es_newStrFromBuf(str + iOffs + pmatch[submatchnbr].rm_so,
+					iLenBuf);
+	}
+
+	if(bMustFree) free(str);
+	if(r[0].datatype == 'S') es_deleteStr(r[0].d.estr);
+	if(r[2].datatype == 'S') es_deleteStr(r[2].d.estr);
+	if(r[3].datatype == 'S') es_deleteStr(r[3].d.estr);
+finalize_it:
+	if(bHadNoMatch) {
+		cnfexprEval(func->expr[4], &r[4], usrptr);
+		estr = var2String(&r[4], &bMustFree);
+		if(r[4].datatype == 'S') es_deleteStr(r[4].d.estr);
+	}
+	ret->datatype = 'S';
+	ret->d.estr = estr;
+	return;
+}
+
+
 /* Perform a function call. This has been moved out of cnfExprEval in order
  * to keep the code small and easier to maintain.
  */
@@ -1331,6 +1421,9 @@ doFuncCall(struct cnffunc *func, struct var *ret, void* usrptr)
 		if(bMustFree) free(str);
 		if(r[0].datatype == 'S') es_deleteStr(r[0].d.estr);
 		break;
+	case CNFFUNC_RE_EXTRACT:
+		doFunc_re_extract(func, ret, usrptr);
+		break;
 	case CNFFUNC_FIELD:
 		cnfexprEval(func->expr[0], &r[0], usrptr);
 		cnfexprEval(func->expr[1], &r[1], usrptr);
@@ -1908,6 +2001,7 @@ cnffuncDestruct(struct cnffunc *func)
 	/* some functions require special destruction */
 	switch(func->fID) {
 		case CNFFUNC_RE_MATCH:
+		case CNFFUNC_RE_EXTRACT:
 			if(func->funcdata != NULL)
 				regexp.regfree(func->funcdata);
 			break;
@@ -2988,7 +3082,6 @@ cnfstmtOptimize(struct cnfstmt *root)
 	struct cnfstmt *stmt;
 	if(root == NULL) goto done;
 	for(stmt = root ; stmt != NULL ; stmt = stmt->next) {
-dbgprintf("RRRR: stmtOptimize: stmt %p, nodetype %u\n", stmt, stmt->nodetype);
 		switch(stmt->nodetype) {
 		case S_IF:
 			cnfstmtOptimizeIf(stmt);
@@ -3088,6 +3181,13 @@ funcName2ID(es_str_t *fname, unsigned short nParams)
 			return CNFFUNC_INVALID;
 		}
 		return CNFFUNC_RE_MATCH;
+	} else if(!es_strbufcmp(fname, (unsigned char*)"re_extract", sizeof("re_extract") - 1)) {
+		if(nParams != 5) {
+			parser_errmsg("number of parameters for re_extract() must be five "
+				      "but is %d.", nParams);
+			return CNFFUNC_INVALID;
+		}
+		return CNFFUNC_RE_EXTRACT;
 	} else if(!es_strbufcmp(fname, (unsigned char*)"field", sizeof("field") - 1)) {
 		if(nParams != 3) {
 			parser_errmsg("number of parameters for field() must be three "
@@ -3118,7 +3218,7 @@ initFunc_re_match(struct cnffunc *func)
 
 	func->funcdata = NULL;
 	if(func->expr[1]->nodetype != 'S') {
-		parser_errmsg("param 2 of re_match() must be a constant string");
+		parser_errmsg("param 2 of re_match/extract() must be a constant string");
 		FINALIZE;
 	}
 
@@ -3196,6 +3296,7 @@ cnffuncNew(es_str_t *fname, struct cnffparamlst* paramlst)
 		/* some functions require special initialization */
 		switch(func->fID) {
 			case CNFFUNC_RE_MATCH:
+			case CNFFUNC_RE_EXTRACT:
 				/* need to compile the regexp in param 2, so this MUST be a constant */
 				initFunc_re_match(func);
 				break;
diff --git a/grammar/rainerscript.h b/grammar/rainerscript.h
index 59ce53f3..4816951b 100644
--- a/grammar/rainerscript.h
+++ b/grammar/rainerscript.h
@@ -226,6 +226,7 @@ enum cnffuncid {
 	CNFFUNC_CSTR,
 	CNFFUNC_CNUM,
 	CNFFUNC_RE_MATCH,
+	CNFFUNC_RE_EXTRACT,
 	CNFFUNC_FIELD,
 	CNFFUNC_PRIFILT
 };