Added regular expression matching script commands and operators

- The script command pcre_match and the operator ~= will return the
  number of regular expression matches in a given string (roughly
  equivalent to the php function preg_match or the perl operator =~)
- The operator ~! is the opposite of ~= (roughly equivalent to the perl
  operator !~)
- See script_commands and npc/custom/test.txt for more information.

Signed-off-by: Haru <haru@dotalux.com>

4 files changed, 166 insertions, 18 deletions

diff --git a/doc/script_commands.txt b/doc/script_commands.txt
index dc09256c5..5e3f62a69 100644
--- a/doc/script_commands.txt
+++ b/doc/script_commands.txt
@@ -725,6 +725,12 @@ other, but you can not compare numbers to strings.
  >   - True if the first value greater than the second value.
  <   - True if the first value is less than the second value.
  !=  - True if the first value IS NOT equal to the second one.
+ ~=  - True if the second value (as regular expression) matches the first
+       value. Both values must be strings. See the script function pcre_match
+       for more details and advanced features.
+ ~!  - True if the second value (as regular expression) DOES NOT match the
+       first value. Both values must be strings. See script function pcre_match
+       for more details and advanced features.
 
 Examples:
 
@@ -732,9 +738,9 @@ Examples:
  1<2 is True while 1>2 is False.
  @x>2 is True if @x is equal to 3. But it isn't true if @x is 2.
 
-Only '==' and '!=' have been tested for comparing strings. Since there's 
-no way to code a seriously complex data structure in this language, trying 
-to sort strings by alphabet would be pointless anyway.
+Only '==', '!=', '~=' and '~!' have been tested for comparing strings. Since
+there's no way to code a seriously complex data structure in this language,
+trying to sort strings by alphabet would be pointless anyway.
 
 Comparisons can be stacked in the same condition:
 
@@ -910,6 +916,8 @@ Precedence  |  Description                                  | Associativity
 ---------------------------------------------------------------------------
 7           | ==  Equal to                                  | Left to right
             | !=  Not equal to                              |
+            | ~=  Regexp match                              |
+            | ~!  Regexp non-match                          |
 ---------------------------------------------------------------------------
 8           |  &  Bitwise AND                               | Left to right
 ---------------------------------------------------------------------------
@@ -7234,15 +7242,54 @@ script is used.
 
 ---------------------------------------
 
+*pcre_match("<string>","<regex>");
+
+This command is only available if the server is compiled with regular
+expressions library enabled.
+
+The string <string> will be searched for a match to the regular expression
+<regex>, and the number of matches will be returned.
+
+An alternative way to invoke this command is to use the operators '~=' or '~!'.
+The operator '~=' is exactly the same as pcre_match, while the operator '~!'
+will return 1 if no matches were found, or 0 if at least a match was found.
+
+	if (pcre_match("string", "regex")) mes "There was a match.";
+	if ("string" ~= "regex") mes "There was a match.";
+	if ("string" ~! "regex") mes "There were no matches.";
+
+You can find more usage examples in the test script npc/custom/test.txt.
+
+Using regular expressions is high wizardry. But with this high wizardry
+comes unparalleled power of text manipulation. For an explanation of what
+a regular expression pattern is, see a few web pages:
+
+http://www.regular-expressions.info/
+http://www.weitz.de/regex-coach/
+
+Additionally, the following temporary variables will be filled (unless the
+command is invoked as '~!'):
+
+- $@regexmatchcount: The number of matches detected, including any
+  parenthesized capture-groups.
+- $@regexmatch$[0]: The part of <string> That matched the full <regex> pattern.
+- $@regexmatch$[1 .. $@regexmatchcount]: The parts of <string> that matched
+  each of the parenthesized capture-groups in <pattern>.
+
+A capture group is a part of a regex enclosed in (parentheses) in order to
+store in a variable the part of the expression that was matched by that part of
+the regex. For more details, see the links above, as this is not intended to be
+a regex tutorial.
+
+---------------------------------------
+
 *defpattern <set number>,"<regular expression pattern>","<event label>";
 *activatepset <set number>;
 *deactivatepset <set number>;
 *deletepset <set number>;
 
 This set of commands is only available if the server is compiled with 
-regular expressions library enabled. Default compilation and most binary 
-distributions aren't, which is probably bad, since these, while complex to 
-use, are quite fascinating.
+regular expressions library enabled.
 
 They will make the NPC object listen for text spoken publicly by players 
 and match it against regular expression patterns, then trigger labels 
@@ -7266,13 +7313,6 @@ pattern set number in this case will deactivate all pattern sets defined.
 'deletepset' will delete a pattern set from memory, so you can create a 
 new pattern set in its place.
 
-Using regular expressions is high wizardry. But with this high wizardry 
-comes unparalleled power of text manipulation. For an explanation of what 
-a regular expression pattern is, see a few web pages:
-
-http://www.regular-expressions.info/
-http://www.weitz.de/regex-coach/
-
 For an example of this in use, see doc/sample/npc_test_pcre.txt
 
 With this you could, for example, automatically punish players for asking 
diff --git a/npc/custom/test.txt b/npc/custom/test.txt
index 00f9c376e..6d1c6b49f 100644
--- a/npc/custom/test.txt
+++ b/npc/custom/test.txt
@@ -335,7 +335,7 @@ OnInit:
 	callsub(OnCheck, "Order of < and <<", .@x);
 
 
-	// ==, != operators
+	// ==, !=, ~=, ~! operators
 	.@x = (0 == 0); // true
 	.@y = (1 == 0); // false
 	callsub(OnCheck, "== operator", .@x);
@@ -344,6 +344,21 @@ OnInit:
 	.@y = (1 != 1); // false
 	callsub(OnCheck, "!= operator", .@x);
 	callsub(OnCheck, "!= operator", .@y, 0);
+	.@x$ = "Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. "
+			"Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. "
+			"Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. "
+			"Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.";
+	.@y = (.@x$ ~= "^Lorem.*, ([a-z]*).*(Duis).* ([a-z.]*)$");
+	callsub(OnCheck, "~= operator", .@y, 4);
+	callsub(OnCheck, "~= operator", $@regexmatchcount, 4);
+	if( $@regexmatchcount == 4 ) {
+		callsub(OnCheck, "~= operator", $@regexmatch$[0], .@x$);
+		callsub(OnCheck, "~= operator", $@regexmatch$[1], "quis");
+		callsub(OnCheck, "~= operator", $@regexmatch$[2], "Duis");
+		callsub(OnCheck, "~= operator", $@regexmatch$[3], "laborum.");
+	}
+	.@y = (.@x$ ~! "^Not Lorem.*, ([a-z]*).*(Duis).* ([a-z.]*)$");
+	callsub(OnCheck, "~! operator", .@y);
 
 	// Associativity of ==, !=
 	.@x = (1 == 0 == 0); // (1 == 0) == 0  -->  0 == 0  --> 1
diff --git a/src/map/script.c b/src/map/script.c
index 17eba6b21..41453e366 100644
--- a/src/map/script.c
+++ b/src/map/script.c
@@ -112,6 +112,10 @@ const char* script_op2name(int op) {
 	RETURN_OP_NAME(C_SUB_POST);
 	RETURN_OP_NAME(C_ADD_PRE);
 	RETURN_OP_NAME(C_SUB_PRE);
+#ifdef PCRE_SUPPORT
+	RETURN_OP_NAME(C_RE_EQ);
+	RETURN_OP_NAME(C_RE_NE);
+#endif // PCRE_SUPPORT
 
 	default:
 		ShowDebug("script_op2name: unexpected op=%d\n", op);
@@ -1224,6 +1228,10 @@ const char* script_parse_subexpr(const char* p,int limit) {
 	|| (op=C_XOR,    opl=4, len=1,*p=='^')              // ^
 	|| (op=C_EQ,     opl=6, len=2,*p=='=' && p[1]=='=') // ==
 	|| (op=C_NE,     opl=6, len=2,*p=='!' && p[1]=='=') // !=
+#ifdef PCRE_SUPPORT
+	|| (op=C_RE_EQ,  opl=6, len=2,*p=='~' && p[1]=='=') // ~=
+	|| (op=C_RE_NE,  opl=6, len=2,*p=='~' && p[1]=='!') // ~!
+#endif // PCRE_SUPPORT
 	|| (op=C_R_SHIFT,opl=8, len=2,*p=='>' && p[1]=='>') // >>
 	|| (op=C_GE,     opl=7, len=2,*p=='>' && p[1]=='=') // >=
 	|| (op=C_GT,     opl=7, len=1,*p=='>')              // >
@@ -3405,6 +3413,8 @@ void op_3(struct script_state* st, int op)
 /// s1 GE s2 -> i
 /// s1 LT s2 -> i
 /// s1 LE s2 -> i
+/// s1 RE_EQ s2 -> i
+/// s1 RE_NE s2 -> i
 /// s1 ADD s2 -> s
 void op_2str(struct script_state* st, int op, const char* s1, const char* s2)
 {
@@ -3417,6 +3427,72 @@ void op_2str(struct script_state* st, int op, const char* s1, const char* s2)
 	case C_GE: a = (strcmp(s1,s2) >= 0); break;
 	case C_LT: a = (strcmp(s1,s2) <  0); break;
 	case C_LE: a = (strcmp(s1,s2) <= 0); break;
+#ifdef PCRE_SUPPORT
+	case C_RE_EQ:
+	case C_RE_NE:
+		{
+			int inputlen = (int)strlen(s1);
+			pcre *compiled_regex;
+			pcre_extra *extra_regex;
+			const char *pcre_error, *pcre_match;
+			int pcre_erroroffset, offsetcount, i;
+			int offsets[256*3]; // (max_capturing_groups+1)*3
+
+			compiled_regex = libpcre->compile(s2, 0, &pcre_error, &pcre_erroroffset, NULL);
+
+			if( compiled_regex == NULL ) {
+				ShowError("script:op2_str: Invalid regex '%s'.\n", s2);
+				script->reportsrc(st);
+				script_pushnil(st);
+				st->state = END;
+				return;
+			}
+
+			extra_regex = libpcre->study(compiled_regex, 0, &pcre_error);
+
+			if( pcre_error != NULL ) {
+				libpcre->free(compiled_regex);
+				ShowError("script:op2_str: Unable to optimize the regex '%s': %s\n", s2, pcre_error);
+				script->reportsrc(st);
+				script_pushnil(st);
+				st->state = END;
+				return;
+			}
+
+			offsetcount = libpcre->exec(compiled_regex, extra_regex, s1, inputlen, 0, 0, offsets, 256*3);
+
+			if( offsetcount == 0 ) {
+				offsetcount = 256;
+			} else if( offsetcount == PCRE_ERROR_NOMATCH ) {
+				offsetcount = 0;
+			} else if( offsetcount < 0 ) {
+				libpcre->free(compiled_regex);
+				if( extra_regex != NULL )
+					libpcre->free(extra_regex);
+				ShowWarning("script:op2_str: Unable to process the regex '%s'.\n", s2);
+				script->reportsrc(st);
+				script_pushnil(st);
+				st->state = END;
+				return;
+			}
+
+			if( op == C_RE_EQ ) {
+				for( i = 0; i < offsetcount; i++ ) {
+					libpcre->get_substring(s1, offsets, offsetcount, i, &pcre_match);
+					mapreg->setregstr(reference_uid(script->add_str("$@regexmatch$"), i), pcre_match);
+					libpcre->free_substring(pcre_match);
+				}
+				mapreg->setreg(script->add_str("$@regexmatchcount"), i);
+				a = offsetcount;
+			} else { // C_RE_NE
+				a = (offsetcount == 0);
+			}
+			libpcre->free(compiled_regex);
+			if( extra_regex != NULL )
+				libpcre->free(extra_regex);
+		}
+		break;
+#endif // PCRE_SUPPORT
 	case C_ADD:
 		{
 			char* buf = (char *)aMalloc((strlen(s1)+strlen(s2)+1)*sizeof(char));
@@ -3988,6 +4064,10 @@ void run_script_main(struct script_state *st) {
 			case C_LOR:
 			case C_R_SHIFT:
 			case C_L_SHIFT:
+#ifdef PCRE_SUPPORT
+			case C_RE_EQ:
+			case C_RE_NE:
+#endif // PCRE_SUPPORT
 				script->op_2(st, c);
 				break;
 
@@ -18500,10 +18580,18 @@ BUILDIN(shopcount) {
 
 // declarations that were supposed to be exported from npc_chat.c
 #ifdef PCRE_SUPPORT
-	BUILDIN(defpattern);
-	BUILDIN(activatepset);
-	BUILDIN(deactivatepset);
-	BUILDIN(deletepset);
+BUILDIN(defpattern);
+BUILDIN(activatepset);
+BUILDIN(deactivatepset);
+BUILDIN(deletepset);
+
+BUILDIN(pcre_match) {
+	const char *input = script_getstr(st, 2);
+	const char *regex = script_getstr(st, 3);
+
+	script->op_2str(st, C_RE_EQ, input, regex);
+	return true;
+}
 #endif
 
 /**
@@ -18867,6 +18955,7 @@ void script_parse_builtin(void) {
 		BUILDIN_DEF(activatepset,"i"), // Activate a pattern set [MouseJstr]
 		BUILDIN_DEF(deactivatepset,"i"), // Deactive a pattern set [MouseJstr]
 		BUILDIN_DEF(deletepset,"i"), // Delete a pattern set [MouseJstr]
+		BUILDIN_DEF(pcre_match,"ss"),
 #endif
 		BUILDIN_DEF(dispbottom,"s"), //added from jA [Lupus]
 		BUILDIN_DEF(getusersname,""),
diff --git a/src/map/script.h b/src/map/script.h
index cf7f22aa9..eed0dbf1d 100644
--- a/src/map/script.h
+++ b/src/map/script.h
@@ -213,6 +213,10 @@ typedef enum c_op {
 	C_SUB_POST, // a--
 	C_ADD_PRE, // ++a
 	C_SUB_PRE, // --a
+#ifdef PCRE_SUPPORT
+	C_RE_EQ, // ~=
+	C_RE_NE, // ~!
+#endif // PCRE_SUPPORT
 } c_op;
 
 enum hQueueOpt {