Improve ellipsize performance

Instead of iterate all ellipsized characters, only iterate the necessary
ranges for copying.

Bug: 188913943
Test: atest CtsTextTestCases CtsGraphicsTestCases CtsWidgetTestCases
Change-Id: I3d03b1e3897e427c23fbe51315f412c57a4ce9e9
(cherry picked from commit 2c6121f3e3c52965ae33317e4fe7a273fd1742c6)
(cherry picked from commit 0c17ccc4af2b28823a12cf846e9222c3c8b472de)

1 files changed, 5 insertions, 4 deletions

diff --git a/core/java/android/text/Layout.java b/core/java/android/text/Layout.java
index c02f7ef65a77..3154acccc6d8 100644
--- a/core/java/android/text/Layout.java
+++ b/core/java/android/text/Layout.java
@@ -2280,7 +2280,10 @@ public abstract class Layout {
         final int ellipsisStringLen = ellipsisString.length();
         // Use the ellipsis string only if there are that at least as many characters to replace.
         final boolean useEllipsisString = ellipsisCount >= ellipsisStringLen;
-        for (int i = 0; i < ellipsisCount; i++) {
+        final int min = Math.max(0, start - ellipsisStart - lineStart);
+        final int max = Math.min(ellipsisCount, end - ellipsisStart - lineStart);
+
+        for (int i = min; i < max; i++) {
             final char c;
             if (useEllipsisString && i < ellipsisStringLen) {
                 c = ellipsisString.charAt(i);
@@ -2289,9 +2292,7 @@ public abstract class Layout {
             }
 
             final int a = i + ellipsisStart + lineStart;
-            if (start <= a && a < end) {
-                dest[destoff + a - start] = c;
-            }
+            dest[destoff + a - start] = c;
         }
     }