correct handling of ANSI control character display lengths

Author: ctongfei

CHANGELOG.md

@@ -2,6 +2,7 @@
  * `0.9.5`:
      - Bugfixes:
         - Fixed the problem of `ProgressState` not being public, thus making `setEtaFunction` useless (#147, PR #146). Thanks @deejgregor, @natanfudge !
+        - Correct handling of ANSI control characters in calculating the display length.
      - New functionalities:
         - Added a new `UNICODE_COLORFUL_BAR` style.
  * `0.9.4`:

src/main/java/me/tongfei/progressbar/ProgressState.java

@@ -21,15 +21,17 @@ public class ProgressState {
     long current;
     long max;
 
-    Instant startInstant = null;
-    Duration elapsedBeforeStart = Duration.ZERO;
+    Instant startInstant;
+    Duration elapsedBeforeStart;
 
     volatile boolean alive = true;
     volatile boolean paused = false;
 
     ProgressState(String taskName, long initialMax, long startFrom, Duration elapsedBeforeStart) {
         this.taskName = taskName;
-        if (initialMax < 0) indefinite = true;
+        if (initialMax < 0)
+            indefinite = true;
+        else this.max = initialMax;
         this.start = startFrom;
         this.current = startFrom;
 

src/main/java/me/tongfei/progressbar/StringDisplayUtils.java

@@ -24,7 +24,10 @@ static int getCharDisplayLength(char c) {
     static int getStringDisplayLength(String s) {
         int displayWidth = 0;
         for (int i = 0; i < s.length(); i++)
-            displayWidth += getCharDisplayLength(s.charAt(i));
+            if (s.charAt(i) == '\033') {  // skip ANSI escape sequences
+                while (i < s.length() && s.charAt(i) != 'm') i++;
+            }
+            else displayWidth += getCharDisplayLength(s.charAt(i));
         return displayWidth;
     }
 
@@ -35,6 +38,10 @@ static String trimDisplayLength(String s, int maxDisplayLength) {
 
         int totalLength = 0;
         for (int i = 0; i < s.length(); i++) {
+            if (s.charAt(i) == '\033') {  // skip ANSI escape sequences
+                while (i < s.length() && s.charAt(i) != 'm') i++;
+                i++;  // skip the 'm' character
+            }
             totalLength += getCharDisplayLength(s.charAt(i));
             if (totalLength > maxDisplayLength) {
                 return s.substring(0, i);