regex: refactoring of continuous capturing groups (#7310)

vlib/regex/README.md

@@ -236,8 +236,8 @@ this is possible initializing the saving array field in `RE` struct: `group_csav
 This feature allow to collect data in a  continuous way.
 
 In the example we pass a text followed by a integer list that we want collect.
-To achieve this task we can use the continuous saving of the group
+To achieve this task we can use the continuous saving of the group 
-that save each captured group in a array that we set with: `re.group_csave = [-1].repeat(3*20+1)`.
+enabling the right flag: `re.group_csave_flag = true`.
 
 The array will be filled with the following logic:
 
@@ -250,14 +250,14 @@ The array will be filled with the following logic:
 The regex save until finish or found that the array have no space.
 If the space ends no error is raised, further records will not be saved.
 
-```v oksyntax
+```v ignore
 fn example2() {
 	test_regex()
 	text := 'tst: 01,23,45 ,56, 78'
 	query := r'.*:(\s*\d+[\s,]*)+'
 	mut re := new() or { panic(err) }
 	// re.debug = 2
-	re.group_csave = [-1].repeat(3 * 20 + 1) // we expect max 20 records
+	re.group_csave_flag = true  // enable continuous capture
 	re.compile_opt(query) or {
 		println(err)
 		return
@@ -330,7 +330,7 @@ fn main() {
 	query := r'(?P<format>https?)|(?:ftps?)://(?P<token>[\w_]+.)+'
 	mut re := new()
 	re.debug = 2
-	// must provide an array of the right size if want the continuos saving of the groups
+	// must provide an array of the right size if want the continuous saving of the groups
 	re.group_csave = [-1].repeat(3 * 20 + 1)
 	re.compile_opt(query) or {
 		println(err)

vlib/regex/regex.v

@@ -314,8 +314,8 @@ pub mut:
 	group_max_nested  int  = 3         // max nested group
 	group_max         int  = 8         // max allowed number of different groups
 
-	group_csave       []int = []int{}  // groups continuous save array
+	group_csave_flag  bool             // flag to enable continuous saving
-	group_csave_index int = -1         // groups continuous save index
+	group_csave       []int = []int{}  // groups continuous save list
 
 	group_map         map[string]int   // groups names map
 
@@ -344,10 +344,7 @@ fn (mut re RE) reset(){
 	re.state_stack_index = -1
 
 	// reset group_csave
-	if re.group_csave.len > 0 {
+	re.group_csave = []int{}
-		re.group_csave_index = 1
-		re.group_csave[0]    = 0 // reset the capture count
-	}
 }
 
 // reset for search mode fail
@@ -1482,6 +1479,45 @@ pub fn (re RE) get_query() string {
 
 /*
 
+Groups saving utilities
+
+*/
+[inline]
+fn (mut re RE) group_continuous_save(g_index int) {
+	if re.group_csave_flag == true {
+		// continuous save, save until we have space
+		
+		// init the first element as counter
+		if re.group_csave.len == 0 {
+			re.group_csave << 0
+		}
+
+		gi    := g_index >> 1
+		start := re.groups[g_index]
+		end   := re.groups[g_index+1]
+
+		// check if we are simply increasing the size ot the found group
+		if re.group_csave.len >=4 &&
+			gi == re.group_csave[re.group_csave.len - 3] &&
+			start == re.group_csave[re.group_csave.len - 2]
+		{
+			re.group_csave[re.group_csave.len - 1] = end
+			return
+		}
+		
+		// otherwise append a new group to the list
+
+		// increment counter
+		re.group_csave[0]++
+		// save the record
+		re.group_csave << (g_index >> 1)        // group id
+		re.group_csave << re.groups[g_index]    // start
+		re.group_csave << re.groups[g_index+1]  // end
+	}
+}
+						
+/*
+
 Matching
 
 */
@@ -1684,18 +1720,8 @@ pub fn (mut re RE) match_base(in_txt byteptr, in_txt_len int ) (int,int) {
 						}
 
 						// continuous save, save until we have space
-						if re.group_csave_index > 0 {
+						re.group_continuous_save(g_index)
-							// check if we have space to save the record
+						
-							if (re.group_csave_index + 3) < re.group_csave.len {
-								// incrment counter
-								re.group_csave[0]++
-								// save the record
-								re.group_csave[re.group_csave_index++] = g_index >> 1          // group id
-								re.group_csave[re.group_csave_index++] = re.groups[g_index]    // start
-								re.group_csave[re.group_csave_index++] = re.groups[g_index+1]  // end
-							}
-						}
-
  					}
 
 					group_index--
@@ -1879,17 +1905,7 @@ pub fn (mut re RE) match_base(in_txt byteptr, in_txt_len int ) (int,int) {
 						//println("GROUP ${re.prog[pc].group_id} END [${re.groups[g_index]}, ${re.groups[g_index+1]}]")
 
 						// continuous save, save until we have space
-						if re.group_csave_index > 0 {
+						re.group_continuous_save(g_index)
-							// check if we have space to save the record
-							if (re.group_csave_index + 3) < re.group_csave.len {
-								// incrment counter
-								re.group_csave[0]++
-								// save the record
-								re.group_csave[re.group_csave_index++] = g_index >> 1          // group id
-								re.group_csave[re.group_csave_index++] = re.groups[g_index]    // start
-								re.group_csave[re.group_csave_index++] = re.groups[g_index+1]  // end
-							}
-						}
 					}
 
 					re.prog[pc].group_rep++ // increase repetitions

vlib/regex/regex_test.v

@@ -230,7 +230,8 @@ fn test_regex(){
 		}
 
 		if to.cgn.len > 0 {
-			re.group_csave = [-1].repeat(3*20+1)
+			re.group_csave_flag = true
+			//re.group_csave = [-1].repeat(3*20+1)
 			if debug { println("continuous save")}
 		} else {
 			if debug { println("NO continuous save")}