[GR-11936] Do not create substrings for 'str.find/rfind'.

PullRequest: graalpython/209

Author: fangerer

graalpython/com.oracle.graal.python.test/src/tests/test_string.py

@@ -29,6 +29,10 @@ def test_rfind():
     assert "test string test".rfind("string") == 5
     assert "test string".rfind("test", 5) == -1
     assert "test string test".rfind("test", None, 12) == 0
+    assert "test string test".rfind("test", 4) == 12
+    assert "test string test".rfind("test", 4, 12) == -1
+    assert "test string test".rfind("test", 4, 14) == -1
+    assert "test string test".rfind("test", None, 14) == 0
 
 
 def test_format():

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/str/StringBuiltins.java

@@ -609,12 +609,14 @@ protected int find(String self, String findStr) {
         @TruffleBoundary
         protected int findWithBounds(String self, String str, int start, int end) {
             if (start != -1 && end != -1) {
-                return self.substring(start, end).lastIndexOf(str);
+                int idx = self.lastIndexOf(str, end - str.length() - 1);
+                return idx >= start ? idx : -1;
             } else if (start != -1) {
-                return self.substring(start).lastIndexOf(str);
+                int idx = self.lastIndexOf(str);
+                return idx >= start ? idx : -1;
             } else {
                 assert end != -1;
-                return self.substring(0, end).lastIndexOf(str);
+                return self.lastIndexOf(str, end - str.length() - 1);
             }
         }
     }
@@ -634,12 +636,14 @@ protected int find(String self, String findStr) {
         @TruffleBoundary
         protected int findWithBounds(String self, String str, int start, int end) {
             if (start != -1 && end != -1) {
-                return self.substring(0, end).indexOf(str, start);
+                int idx = self.indexOf(str, start);
+                return idx + str.length() <= end ? idx : -1;
             } else if (start != -1) {
                 return self.indexOf(str, start);
             } else {
                 assert end != -1;
-                return self.substring(0, end).indexOf(str);
+                int idx = self.indexOf(str);
+                return idx + str.length() <= end ? idx : -1;
             }
         }
     }