2013-04-10 Bin Cheng <bin.cheng@arm.com>

        * acconfig.h (_FSEEK_OPTIMIZATION): Undef
        * newlib.hin (_FSEEK_OPTIMIZATION): Undef
        * configure.in (--disable-newlib-fseek-optimization): New option.
        * configure: Regenerated.
        * libc/stdio/fflush.c (__sflush_r): Use _FSEEK_OPTIMIZATION to
        control fseek optimization.
        * libc/stdio/fseeko.c (_fseeko_r): Ditto.
        * libc/stdio/makebuf.c (__smakebuf_r): Ditto.
        * libc/stdio64/fseeko64.c (_fseeko64_r): Ditto.

4 files changed, 14 insertions, 0 deletions

diff --git a/newlib/libc/stdio/fflush.c b/newlib/libc/stdio/fflush.c
index b2bde7af5..ee24cf7ca 100644
--- a/newlib/libc/stdio/fflush.c
+++ b/newlib/libc/stdio/fflush.c
@@ -80,10 +80,12 @@ _DEFUN(__sflush_r, (ptr, fp),
   t = fp->_flags;
   if ((t & __SWR) == 0)
     {
+#ifdef _FSEEK_OPTIMIZATION
       /* For a read stream, an fflush causes the next seek to be
          unoptimized (i.e. forces a system-level seek).  This conforms
          to the POSIX and SUSv3 standards.  */
       fp->_flags |= __SNPT;
+#endif
 
       /* For a seekable stream with buffered read characters, we will attempt
          a seek to the current position now.  A subsequent read will then get
@@ -152,7 +154,9 @@ _DEFUN(__sflush_r, (ptr, fp),
 	    {
 	      /* Seek successful or ignorable error condition.
 		 We can clear read buffer now.  */
+#ifdef _FSEEK_OPTIMIZATION
 	      fp->_flags &= ~__SNPT;
+#endif
 	      fp->_r = 0;
 	      fp->_p = fp->_bf._base;
 	      if ((fp->_flags & __SOFF) && (curoff != -1 || ptr->_errno == 0))
diff --git a/newlib/libc/stdio/fseeko.c b/newlib/libc/stdio/fseeko.c
index 97eafd9ca..2c9419d97 100644
--- a/newlib/libc/stdio/fseeko.c
+++ b/newlib/libc/stdio/fseeko.c
@@ -219,6 +219,8 @@ _DEFUN(_fseeko_r, (ptr, fp, offset, whence),
 
   if (fp->_bf._base == NULL)
     __smakebuf_r (ptr, fp);
+
+#ifdef _FSEEK_OPTIMIZATION
   if (fp->_flags & (__SWR | __SRW | __SNBF | __SNPT))
     goto dumb;
   if ((fp->_flags & __SOPT) == 0)
@@ -350,6 +352,7 @@ _DEFUN(_fseeko_r, (ptr, fp, offset, whence),
    * We get here if we cannot optimise the seek ... just
    * do it.  Allow the seek function to change fp->_bf._base.
    */
+#endif
 
 dumb:
   if (_fflush_r (ptr, fp)
diff --git a/newlib/libc/stdio/makebuf.c b/newlib/libc/stdio/makebuf.c
index a3f47e2f7..349783ded 100644
--- a/newlib/libc/stdio/makebuf.c
+++ b/newlib/libc/stdio/makebuf.c
@@ -65,8 +65,10 @@ _DEFUN(__smakebuf_r, (ptr, fp),
         size = _DEFAULT_ASPRINTF_BUFSIZE;
       else
         size = BUFSIZ;
+#ifdef _FSEEK_OPTIMIZATION
       /* do not try to optimise fseek() */
       fp->_flags |= __SNPT;
+#endif
     }
   else
     {
@@ -76,6 +78,7 @@ _DEFUN(__smakebuf_r, (ptr, fp),
 #else
       size = BUFSIZ;
 #endif
+#ifdef _FSEEK_OPTIMIZATION
       /*
        * Optimize fseek() only if it is a regular file.
        * (The test for __sseek is mainly paranoia.)
@@ -91,6 +94,7 @@ _DEFUN(__smakebuf_r, (ptr, fp),
 	}
       else
 	fp->_flags |= __SNPT;
+#endif
     }
   if ((p = _malloc_r (ptr, size)) == NULL)
     {
diff --git a/newlib/libc/stdio64/fseeko64.c b/newlib/libc/stdio64/fseeko64.c
index b323f97d8..d605dd09b 100644
--- a/newlib/libc/stdio64/fseeko64.c
+++ b/newlib/libc/stdio64/fseeko64.c
@@ -209,6 +209,8 @@ _DEFUN (_fseeko64_r, (ptr, fp, offset, whence),
 
   if (fp->_bf._base == NULL)
     __smakebuf_r (ptr, fp);
+
+#if _FSEEK_OPTIMIZATION
   if (fp->_flags & (__SWR | __SRW | __SNBF | __SNPT))
     goto dumb;
   if ((fp->_flags & __SOPT) == 0)
@@ -330,6 +332,7 @@ _DEFUN (_fseeko64_r, (ptr, fp, offset, whence),
    * We get here if we cannot optimise the seek ... just
    * do it.  Allow the seek function to change fp->_bf._base.
    */
+#endif
 
 dumb:
   if (_fflush_r (ptr, fp)