From 9f63dce8815693b20cef63a205e19913c06a077a Mon Sep 17 00:00:00 2001
From: Markus Scherer <markus.icu@gmail.com>
Date: Mon, 14 Aug 2000 23:05:10 +0000
Subject: [PATCH] ICU-471 improve checks for preflighting

X-SVN-Rev: 2228
---
 icu4c/source/common/ushape.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/icu4c/source/common/ushape.c b/icu4c/source/common/ushape.c
index 6b3e35e627..9b9ca69fe3 100644
--- a/icu4c/source/common/ushape.c
+++ b/icu4c/source/common/ushape.c
@@ -101,8 +101,9 @@ u_shapeArabic(const UChar *source, int32_t sourceLength,
         return 0;
     }
 
-    /* also make sure that no reserved options values are used */
-    if( source==NULL || sourceLength<-1 || dest==NULL || destSize<0 ||
+    /* make sure that no reserved options values are used; allow dest==NULL only for preflighting */
+    if( source==NULL || sourceLength<-1 ||
+        dest==NULL && destSize!=0 || destSize<0 ||
         options>=U_SHAPE_DIGIT_TYPE_RESERVED ||
         (options&U_SHAPE_LENGTH_MASK)==U_SHAPE_LENGTH_RESERVED ||
         (options&U_SHAPE_LETTERS_MASK)==U_SHAPE_LETTERS_RESERVED ||
@@ -121,8 +122,9 @@ u_shapeArabic(const UChar *source, int32_t sourceLength,
     }
 
     /* check that source and destination do not overlap */
-    if( source<=dest && dest<source+sourceLength ||
-        dest<=source && source<dest+destSize
+    if( dest!=NULL &&
+        (source<=dest && dest<source+sourceLength ||
+         dest<=source && source<dest+destSize)
     ) {
         *pErrorCode=U_ILLEGAL_ARGUMENT_ERROR;
         return 0;
@@ -138,6 +140,7 @@ u_shapeArabic(const UChar *source, int32_t sourceLength,
          * just make sure the destination is large enough and copy the string.
          */
         if(destSize<sourceLength) {
+            /* this catches preflighting, too */
             *pErrorCode=U_BUFFER_OVERFLOW_ERROR;
             return sourceLength;
         }