From 183dadb915e783ae27dadb8d5a5a910c76caafbe Mon Sep 17 00:00:00 2001
From: Andy Heninger <andy.heninger@gmail.com>
Date: Fri, 17 Apr 2009 23:50:13 +0000
Subject: [PATCH] ICU-5572 improved UText of empty string construction

X-SVN-Rev: 25824
---
 icu4c/source/common/utext.cpp           | 12 ++++++++++-
 icu4c/source/test/cintltst/utexttst.c   | 24 ++++++++++++++++++++-
 icu4c/source/test/intltest/utxttest.cpp | 28 ++++++++++++++++++++++---
 3 files changed, 59 insertions(+), 5 deletions(-)

diff --git a/icu4c/source/common/utext.cpp b/icu4c/source/common/utext.cpp
index 40266ffb86..e1ea672bab 100644
--- a/icu4c/source/common/utext.cpp
+++ b/icu4c/source/common/utext.cpp
@@ -1603,11 +1603,17 @@ static const struct UTextFuncs utf8Funcs =
 };
 
 
+static const char gEmptyString[] = {0};
+
 U_CAPI UText * U_EXPORT2
 utext_openUTF8(UText *ut, const char *s, int64_t length, UErrorCode *status) {
     if(U_FAILURE(*status)) {
         return NULL;
     }
+    if(s==NULL && length==0) {
+        s = gEmptyString;
+    }
+
     if(s==NULL || length<-1 || length>INT32_MAX) {
         *status=U_ILLEGAL_ARGUMENT_ERROR;
         return NULL;
@@ -2570,13 +2576,17 @@ static const struct UTextFuncs ucstrFuncs =
 
 U_CDECL_END
 
+static const UChar gEmptyUString[] = {0};
 
 U_CAPI UText * U_EXPORT2
 utext_openUChars(UText *ut, const UChar *s, int64_t length, UErrorCode *status) {
     if (U_FAILURE(*status)) {
         return NULL;
     }
-    if (length < -1 || length>INT32_MAX) {
+    if(s==NULL && length==0) {
+        s = gEmptyUString;
+    }
+    if (s==NULL || length < -1 || length>INT32_MAX) {
         *status = U_ILLEGAL_ARGUMENT_ERROR;
         return NULL;
     }
diff --git a/icu4c/source/test/cintltst/utexttst.c b/icu4c/source/test/cintltst/utexttst.c
index be5941df40..734ee85eff 100644
--- a/icu4c/source/test/cintltst/utexttst.c
+++ b/icu4c/source/test/cintltst/utexttst.c
@@ -1,6 +1,6 @@
 /********************************************************************
  * COPYRIGHT: 
- * Copyright (c) 2005-2006, International Business Machines Corporation and
+ * Copyright (c) 2005-2009, International Business Machines Corporation and
  * others. All Rights Reserved.
  ********************************************************************/
 /*
@@ -180,6 +180,28 @@ static void TestAPI(void) {
         utext_close(uta);
     }
 
+    {
+        /*
+         * UText opened on a NULL string with zero length
+         */
+        UText    *uta;
+        UChar32   c;
+
+        status = U_ZERO_ERROR;
+        uta = utext_openUChars(NULL, NULL, 0, &status);
+        TEST_SUCCESS(status);
+        c = UTEXT_NEXT32(uta);
+        TEST_ASSERT(c == U_SENTINEL);
+        utext_close(uta);
+
+        uta = utext_openUTF8(NULL, NULL, 0, &status);
+        TEST_SUCCESS(status);
+        c = UTEXT_NEXT32(uta);
+        TEST_ASSERT(c == U_SENTINEL);
+        utext_close(uta);
+    }
+
+
     {
         /*
          * extract
diff --git a/icu4c/source/test/intltest/utxttest.cpp b/icu4c/source/test/intltest/utxttest.cpp
index 6c5c568c3f..c84b3652bf 100644
--- a/icu4c/source/test/intltest/utxttest.cpp
+++ b/icu4c/source/test/intltest/utxttest.cpp
@@ -278,9 +278,9 @@ void UTextTest::TestString(const UnicodeString &s) {
 
 
 
-	delete []cpMap;
-	delete []u8Map;
-	delete []u8String;
+    delete []cpMap;
+    delete []u8Map;
+    delete []u8String;
 }
 
 //  TestCMR   test Copy, Move and Replace operations.
@@ -904,6 +904,28 @@ void UTextTest::ErrorTest()
         TEST_ASSERT(utp == &ut);
     }
 
+    // Invalid parameters on open
+    //
+    {
+        UErrorCode status = U_ZERO_ERROR;
+        UText ut = UTEXT_INITIALIZER;
+        
+        utext_openUChars(&ut, NULL, 5, &status);
+        TEST_ASSERT(status == U_ILLEGAL_ARGUMENT_ERROR);
+
+        status = U_ZERO_ERROR;
+        utext_openUChars(&ut, NULL, -1, &status);
+        TEST_ASSERT(status == U_ILLEGAL_ARGUMENT_ERROR);
+
+        status = U_ZERO_ERROR;
+        utext_openUTF8(&ut, NULL, 4, &status);
+        TEST_ASSERT(status == U_ILLEGAL_ARGUMENT_ERROR);
+
+        status = U_ZERO_ERROR;
+        utext_openUTF8(&ut, NULL, -1, &status);
+        TEST_ASSERT(status == U_ILLEGAL_ARGUMENT_ERROR);
+    }
+
     //
     //  UTF-8 with malformed sequences.
     //    These should come through as the Unicode replacement char, \ufffd