Fix some bugs in escapeSplit

The main bug was that if you started the string with a delimiter, you
would only get an empty string as a result. Turns out endsWith("") is
usually true :-|

Also, added some more tests, and some more early outs to escapeSplit.

2 files changed, 50 insertions, 8 deletions

diff --git a/src/main/java/bjc/everge/StringUtils.java b/src/main/java/bjc/everge/StringUtils.java
index 3f19b8f..3b40832 100644
--- a/src/main/java/bjc/everge/StringUtils.java
+++ b/src/main/java/bjc/everge/StringUtils.java
@@ -4,12 +4,16 @@ import java.util.Arrays;
 import java.util.ArrayList;
 import java.util.List;
 
+import java.util.regex.Pattern;
+
 /**
  * Utility methods for strings.
  *
  * @author Ben Culkin.
  */
 public class StringUtils {
+	public static boolean isDebug = false;
+
 	/**
 	 * Split a string on every occurance of a string not preceeded by an escape.
 	 *
@@ -22,8 +26,22 @@ public class StringUtils {
 	 * @return The string split as specified above.
 	 */
 	public static String[] escapeSplit(String escape, String splat, String inp) {
+		/*
+		 * Special case some stuffs.
+		 */
+		if (inp == null || inp.equals("")) {
+			// No input
+			return new String[] {inp};
+		}
+
+		if (!inp.contains(splat)) {
+			// Input does not contain any delimiters
+			return new String[] {inp};
+		}
+
 		if (escape == null || escape.equals("")) {
-			return inp.split(splat);
+			// No escape, so we can just split normally
+			return inp.split(Pattern.quote(splat));
 		}
 
 		List<String> ret = new ArrayList<>();
@@ -31,25 +49,38 @@ public class StringUtils {
 		String wrk = inp;
 		int idx = wrk.indexOf(splat);
 
-		// System.err.printf("[DEBUG] 'hard' escapeSplit: (%s) (%s) (%s) init: %d\n",
-		// 		escape, splat, inp, idx);
+		if (isDebug) {
+			System.err.printf("[DEBUG] 'hard' escapeSplit: (%s) (%s) (%s) init: %d\n",
+					escape, splat, inp, idx);
+		}
 
 		while (idx != -1) {
-			while (idx != -1 && wrk.regionMatches(idx - 1, escape, 0, escape.length())) {
+			boolean hasEscape = wrk.regionMatches(idx - 1, escape, 0, escape.length());
+
+			while (idx != -1 && hasEscape) {
 				int oidx = wrk.indexOf(splat, idx + 1);
-				// System.err.printf("[TRACE] idx: %d, oidx: %d\n", idx, oidx);
+
+				if (isDebug) {
+					System.err.printf("[TRACE] idx: %d, oidx: %d\n", idx, oidx);
+				}
+
 				idx = oidx;
+
+				hasEscape = wrk.regionMatches(idx - 1, escape, 0, escape.length());
 			}
 		
 			if (idx == -1) {
 				break;
 			}
 
-			// System.err.printf("[TRACE] sliced string into (%s) and (%s) at %d\n",
-			// 		wrk.substring(0, idx), wrk.substring(idx), idx);
+			if (isDebug) {
+				System.err.printf("[TRACE] sliced string into (%s) and (%s) at %d\n",
+						wrk.substring(0, idx), wrk.substring(idx), idx);
+			}
+
 			String tmp = wrk.substring(0, idx);
 			ret.add(tmp);
-			if (wrk.endsWith(tmp)) {
+			if (!tmp.equals("") && wrk.endsWith(tmp)) {
 				wrk = "";
 			} else {
 				wrk = wrk.substring(idx + splat.length());
@@ -58,6 +89,10 @@ public class StringUtils {
 			idx = wrk.indexOf(splat);
 		}
 
+		if (isDebug) {
+			System.err.printf("\t[TRACE] Remnant is (%s) for string (%s)\n", wrk, inp);
+		}
+
 		if (!wrk.equals("")) ret.add(wrk);
 
 		return ret.toArray(new String[0]);
diff --git a/src/test/java/bjc/everge/StringUtilsTest.java b/src/test/java/bjc/everge/StringUtilsTest.java
index 9edc028..9eac017 100644
--- a/src/test/java/bjc/everge/StringUtilsTest.java
+++ b/src/test/java/bjc/everge/StringUtilsTest.java
@@ -28,6 +28,13 @@ public class StringUtilsTest {
 		assertSplitsTo("a /  b/c", "/", " ", "a", "/ ", "b/c");
 	}
 
+	@Test
+	public void testEdgeSplit() {
+		// Starting with the delimiter doesn't create a blank string
+		assertSplitsTo("/a", "|", "/", "", "a");
+		assertSplitsTo("a/", "|", "/", "a");
+	}
+
 	private void assertSplitsTo(String inp, String esc, String splat, String... right) {
 		try {
 			String[] lst = StringUtils.escapeSplit(esc, splat, inp);