Improve performance of removeColor. (#1079)

2 files changed, 90 insertions, 14 deletions

diff --git a/src/main/java/at/hannibal2/skyhanni/utils/StringUtils.kt b/src/main/java/at/hannibal2/skyhanni/utils/StringUtils.kt
index 192073111..a8ab6e6cd 100644
--- a/src/main/java/at/hannibal2/skyhanni/utils/StringUtils.kt
+++ b/src/main/java/at/hannibal2/skyhanni/utils/StringUtils.kt
@@ -34,7 +34,7 @@ object StringUtils {
         return first + lowercase.substring(1)
     }
 
-    private val formattingChars by lazy { "kmolnr".toCharArray() + "kmolnr".uppercase().toCharArray() }
+    private val formattingChars = "kmolnrKMOLNR".toSet()
 
     /**
      * Removes color and optionally formatting codes from the given string, leaving plain text.
@@ -42,22 +42,53 @@ object StringUtils {
      * @param keepFormatting Boolean indicating whether to retain non-color formatting codes (default: false).
      * @return A string with color codes removed (and optionally formatting codes if specified).
      */
-    fun String.removeColor(keepFormatting: Boolean = false): String {
-        val builder = StringBuilder(this.length)
-
-        var counter = 0
-        while (counter < this.length) {
-            if (this[counter] == '§') {
-                if (!keepFormatting || this[counter + 1] !in formattingChars) {
-                    counter += 2
-                    continue
-                }
+    fun CharSequence.removeColor(keepFormatting: Boolean = false): String {
+        // Glossary:
+        // Formatting indicator: The '§' character indicating the beginning of a formatting sequence
+        // Formatting code: The character following a formatting indicator which specifies what color or text style this sequence corresponds to
+        // Formatting sequence: The combination of a formatting indicator and code that changes the color or format of a string
+
+        // Find the first formatting indicator
+        var nextFormattingSequence = indexOf('§')
+
+        // If this string does not contain any formatting indicators, just return this string directly
+        if (nextFormattingSequence < 0) return this.toString()
+
+        // Let's create a new string, and pre-allocate enough space to store this entire string
+        val cleanedString = StringBuilder(this.length)
+
+        // Read index stores the position in `this` which we have written up until now
+        // a/k/a where we need to start reading from
+        var readIndex = 0
+
+        // As long as there still is a formatting indicator left in our string
+        while (nextFormattingSequence >= 0) {
+
+            // Write everything from the read index up to the next formatting indicator into our clean string
+            cleanedString.append(this, readIndex, nextFormattingSequence)
+
+            // If the next formatting sequence's code indicates a non-color format and we should keep those
+            if (keepFormatting && nextFormattingSequence + 1 < length && this[nextFormattingSequence + 1] in formattingChars) {
+                // Set the readIndex to the formatting indicator, so that the next loop will start writing from that paragraph symbol
+                readIndex = nextFormattingSequence
+                // Find the next § symbol after the formatting sequence
+                nextFormattingSequence = indexOf('§', startIndex = readIndex + 1)
+            } else {
+                // If this formatting sequence should be skipped (either a color code, or !keepFormatting or an incomplete formatting sequence without a code)
+                // Set the readIndex to after this formatting sequence, so that the next loop will skip over it before writing the string
+                readIndex = nextFormattingSequence + 2
+                // Find the next § symbol after the formatting sequence
+                nextFormattingSequence = indexOf('§', startIndex = readIndex)
+
+                // If the next read would be out of bound, reset the readIndex to the very end of the string, resulting in a "" string to be appended
+                readIndex = readIndex.coerceAtMost(this.length)
             }
-            builder.append(this[counter])
-            counter++
         }
+        // Finally, after the last formatting sequence was processed, copy over the last sequence of the string
+        cleanedString.append(this, readIndex, this.length)
 
-        return builder.toString()
+        // And turn the string builder into a string
+        return cleanedString.toString()
     }
 
     fun UUID.toDashlessUUID(): String {
diff --git a/src/test/java/at/hannibal2/skyhanni/test/RemoveColorTest.kt b/src/test/java/at/hannibal2/skyhanni/test/RemoveColorTest.kt
new file mode 100644
index 000000000..f12f295fa
--- /dev/null
+++ b/src/test/java/at/hannibal2/skyhanni/test/RemoveColorTest.kt
@@ -0,0 +1,45 @@
+package at.hannibal2.skyhanni.test
+
+import at.hannibal2.skyhanni.utils.StringUtils.removeColor
+import org.junit.jupiter.api.Assertions
+import org.junit.jupiter.api.Test
+
+class RemoveColorTest {
+    @Test
+    fun testEdging() {
+        Assertions.assertEquals("", "§".removeColor())
+        Assertions.assertEquals("a", "a§".removeColor())
+        Assertions.assertEquals("b", "§ab§".removeColor())
+    }
+
+    @Test
+    fun `testDouble§`() {
+        Assertions.assertEquals("1", "§§1".removeColor())
+        Assertions.assertEquals("1", "§§1".removeColor(true))
+        Assertions.assertEquals("k", "§§k".removeColor(true))
+    }
+
+    @Test
+    fun testKeepNonColor() {
+        Assertions.assertEquals("§k§l§m§n§o§r", "§k§l§m§f§n§o§r".removeColor(true))
+    }
+
+    @Test
+    fun testPlainString() {
+        Assertions.assertEquals("bcdefgp", "bcdefgp")
+        Assertions.assertEquals("", "")
+    }
+
+    @Test
+    fun testSomeNormalTestCases() {
+        Assertions.assertEquals(
+            "You are not currently in a party.",
+            "§r§cYou are not currently in a party.§r".removeColor()
+        )
+        Assertions.assertEquals(
+            "Ancient Necron's Chestplate ✪✪✪✪",
+            "§dAncient Necron's Chestplate §6✪§6✪§6✪§6✪".removeColor()
+        )
+    }
+
+}