Cleanup latin-1 conversion check in regexp engine

test/cctest/test-strings.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 
 // Check that we can traverse very deep stacks of ConsStrings using
 // StringCharacterStram.  Check that Get(int) works on very deep stacks
 // of ConsStrings.  These operations may not be very fast, but they
 // should be possible without getting errors due to too deep recursion.
 
 #include <stdlib.h>
 
 #include "v8.h"
@@ skipping 1257 matching lines @@
 
   v8::Local<v8::String> expected = v8_str("ascii\x80only\x80string\x80");
   CHECK(expected->Equals(result));
 }
 
 
 TEST(IsAscii) {
   CHECK(String::IsAscii(static_cast<char*>(NULL), 0));
   CHECK(String::IsOneByte(static_cast<uc16*>(NULL), 0));
 }
+
+
+static bool CanBeConvertedToLatin1(uint16_t c) {
+  CHECK(c > unibrow::Latin1::kMaxChar);
+  uint32_t result[4];
+  int chars;
+  chars = unibrow::ToLowercase::Convert(c, 0, result, NULL);
+  if (chars > 0) {
+    CHECK_LE(chars, static_cast<int>(sizeof(result)));
+    for (int i = 0; i < chars; i++ ) {
+      if (result[i] <= unibrow::Latin1::kMaxChar) {
+        return true;
+      }
+    }
+  }
+  chars = unibrow::ToUppercase::Convert(c, 0, result, NULL);
+  if (chars > 0) {
+    CHECK_LE(chars, static_cast<int>(sizeof(result)));
+    for (int i = 0; i < chars; i++ ) {
+      if (result[i] <= unibrow::Latin1::kMaxChar) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
+
+TEST(Latin1) {
+#ifndef ENABLE_LATIN_1
+    if (true) return;
+#endif
+  for (uint16_t c = unibrow::Latin1::kMaxChar + 1; c != 0; c++) {
+    CHECK_EQ(CanBeConvertedToLatin1(c),
+             unibrow::Latin1::NonLatin1CanBeConvertedToLatin1(c));
+  }
+}