Update ICU to 58.1

source/common/bytestrieiterator.cpp

Index: source/common/bytestrieiterator.cpp
diff --git a/source/common/bytestrieiterator.cpp b/source/common/bytestrieiterator.cpp
index e50f07c24fee650881a300d2ecef9de3d8b72670..4d04247c4933d0a7ef6255761151b923641b4767 100644
--- a/source/common/bytestrieiterator.cpp
+++ b/source/common/bytestrieiterator.cpp
@@ -1,3 +1,5 @@
+// Copyright (C) 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
 /*
 *******************************************************************************
 *   Copyright (C) 2010-2012, International Business Machines
@@ -139,7 +141,6 @@ BytesTrie::Iterator::next(UErrorCode &errorCode) {
             } else {
                 pos_=skipValue(pos, node);
             }
-            sp_.set(str_->data(), str_->length());
             return TRUE;
         }
         if(maxLength_>0 && str_->length()==maxLength_) {
@@ -167,10 +168,14 @@ BytesTrie::Iterator::next(UErrorCode &errorCode) {
     }
 }
 
+StringPiece
+BytesTrie::Iterator::getString() const {
+    return str_ == NULL ? StringPiece() : str_->toStringPiece();
+}
+
 UBool
 BytesTrie::Iterator::truncateAndStop() {
     pos_=NULL;
-    sp_.set(str_->data(), str_->length());
     value_=-1;  // no real value for str
     return TRUE;
 }
@@ -199,7 +204,6 @@ BytesTrie::Iterator::branchNext(const uint8_t *pos, int32_t length, UErrorCode &
     str_->append((char)trieByte, errorCode);
     if(isFinal) {
         pos_=NULL;
-        sp_.set(str_->data(), str_->length());
         value_=value;
         return NULL;
     } else {