From 940a3f8f1ced4f833160611f297f005ee0770946 Mon Sep 17 00:00:00 2001
From: Ram Viswanadha <rviswanadha@gmail.com>
Date: Fri, 22 Nov 2002 23:43:32 +0000
Subject: [PATCH] ICU-2474 dont make multiple calls to ungetc

X-SVN-Rev: 10352
---
 icu4c/source/tools/toolutil/ucbuf.c | 15 ++++++---------
 1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/icu4c/source/tools/toolutil/ucbuf.c b/icu4c/source/tools/toolutil/ucbuf.c
index ce99378310..378e7403e4 100644
--- a/icu4c/source/tools/toolutil/ucbuf.c
+++ b/icu4c/source/tools/toolutil/ucbuf.c
@@ -57,12 +57,12 @@ ucbuf_autodetect_fs(FileStream* in, const char** cp, UConverter** conv, int32_t*
     numRead=T_FileStream_read(in, start, sizeof(start));
 
     *cp = ucnv_detectUnicodeSignature(start, numRead, signatureLength, error);
-    if(*cp==NULL){
-        /* unread the bytes already read */
-        while(numRead>0) {
-            T_FileStream_ungetc(start[--numRead], in);
-        }
+    
+    /* unread the bytes beyond what was consumed for U+FEFF */
+    T_FileStream_rewind(in);
+    numRead = T_FileStream_read(in, start,*signatureLength);
 
+    if(*cp==NULL){
         *conv =NULL;
         return FALSE;
     }
@@ -84,10 +84,7 @@ ucbuf_autodetect_fs(FileStream* in, const char** cp, UConverter** conv, int32_t*
         *error=U_INTERNAL_PROGRAM_ERROR;
     }
 
-    /* unread the bytes beyond what was consumed for U+FEFF */
-    while(numRead>*signatureLength) {
-        T_FileStream_ungetc(start[--numRead], in);
-    }
+
 
     return TRUE; 
 }