From 831e2fb1cd4fc12dbd3e9ac761af7c87223a85b9 Mon Sep 17 00:00:00 2001
From: ache <ache@FreeBSD.org>
Date: Thu, 30 Aug 2001 20:49:47 +0000
Subject: Try to discard some ungetc data in saved internal buffer checks too,
 if offset tends to be negative.

---
 lib/libc/stdio/fseek.c | 20 ++++++++++++++++----
 lib/libc/stdio/ftell.c | 12 +++++++++---
 2 files changed, 25 insertions(+), 7 deletions(-)

(limited to 'lib')

diff --git a/lib/libc/stdio/fseek.c b/lib/libc/stdio/fseek.c
index aa886d2..8af60ba 100644
--- a/lib/libc/stdio/fseek.c
+++ b/lib/libc/stdio/fseek.c
@@ -151,8 +151,14 @@ _fseeko(fp, offset, whence, ltest)
 			if (HASUB(fp)) {
 				curoff -= fp->_ur;
 				if (curoff < 0) {
-					errno = EBADF;
-					return (-1);
+					if (-curoff <= fp->_r) {
+						fp->_p -= curoff;
+						fp->_r += curoff;
+						curoff = 0;
+					} else {
+						errno = EBADF;
+						return (-1);
+					}
 				}
 			}
 		} else if ((fp->_flags & __SWR) && fp->_p != NULL) {
@@ -261,8 +267,14 @@ _fseeko(fp, offset, whence, ltest)
 		}
 		if (HASUB(fp)) {
 			curoff -= fp->_ur;
-			if (curoff < 0)
-				goto dumb;
+			if (curoff < 0) {
+				if (-curoff <= fp->_r) {
+					fp->_p -= curoff;
+					fp->_r += curoff;
+					curoff = 0;
+				} else
+					goto dumb;
+			}
 		}
 	}
 
diff --git a/lib/libc/stdio/ftell.c b/lib/libc/stdio/ftell.c
index 38a164e..46a309c 100644
--- a/lib/libc/stdio/ftell.c
+++ b/lib/libc/stdio/ftell.c
@@ -118,9 +118,15 @@ ftello(fp)
 		if (HASUB(fp)) {
 			pos -= fp->_ur;
 			if (pos < 0) {
-				errno = EBADF;
-				FUNLOCKFILE(fp);
-				return (-1);
+				if (-pos <= fp->_r) {
+					fp->_p -= pos;
+					fp->_r += pos;
+					pos = 0;
+				} else {
+					errno = EBADF;
+					FUNLOCKFILE(fp);
+					return (-1);
+				}
 			}
 		}
 	} else if ((fp->_flags & __SWR) && fp->_p != NULL) {
-- 
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