Extract StringUtils.countPushback(String, Pattern)

Author: idodeclare

src/org/opensolaris/opengrok/analysis/JFlexXref.java

@@ -273,13 +273,8 @@ protected void appendLink(String url, boolean doEndingPushback,
         if (doEndingPushback) {
             n = StringUtils.countURIEndingPushback(url);
         }
-        if (collateralCapture != null) {
-            int o = StringUtils.patindexOf(url, collateralCapture);
-            if (o > 0) {
-                int ccn = url.length() - o;
-                if (ccn > n) n = ccn;
-            }
-        }
+        int ccn = StringUtils.countPushback(url, collateralCapture);
+        if (ccn > n) n = ccn;
         // Push back if positive, but not if equal to the current length.
         if (n > 0 && n < url.length()) {
             yypushback(n);

src/org/opensolaris/opengrok/util/StringUtils.java

@@ -287,4 +287,28 @@ public static int patindexOf(String value, Pattern pattern) {
     public static boolean startsWithFpathChar(String value) {
         return FPATH_CHAR_STARTSMATCH.matcher(value).matches();
     }
+
+    /**
+     * Determines if the specified pattern, {@code pat}, matches the specified
+     * {@code capture}, and computes an eligible pushback.
+     * @param capture a defined input
+     * @param pat a pattern, or null to skip computation
+     * @return a positive value if {@code pat} matches in {@code capture} at or
+     * after the second character to indicate the number of characters to
+     * pushback including the first-matched character; otherwise 0 to indicate
+     * no match or a match at the 0-th character. (The 0-th chracter is
+     * ineligible for fear of looping non-stop upon pushing back the entire
+     * {@code yytext()}.)
+     */
+    public static int countPushback(String capture, Pattern pat) {
+        if (pat != null) {
+            int o = StringUtils.patindexOf(capture, pat);
+            if (o >= 0) {
+                int n = capture.length() - o;
+                // Push back if positive, but not if equal to the full length.
+                if (n > 0 && n < capture.length()) return n;
+            }
+        }
+        return 0;
+    }
 }