(_IO_str_seekoff): Handle MODE == 0.

diff --git a/libio/strops.c b/libio/strops.c
index afc293bd7d2fce1e9c136c0616f776de89309677..ed55c8e836d635bd833e8268a5ca7a431a8aac4b 100644 (file)
--- a/libio/strops.c
+++ b/libio/strops.c
@@ -202,48 +202,62 @@ _IO_pos_t
 DEFUN(_IO_str_seekoff, (fp, offset, dir, mode),
       register _IO_FILE *fp AND _IO_off_t offset AND int dir AND int mode)
 {
-  _IO_ssize_t cur_size = _IO_str_count(fp);
-  _IO_pos_t new_pos = EOF;
+  _IO_pos_t new_pos;
 
-  /* Move the get pointer, if requested. */
-  if (mode & _IOS_INPUT)
+  if (mode == 0)
     {
-      switch (dir)
+      /* Don't move any pointers. But there is no clear indication what
+        mode FP is in. Let's guess. */
+      if (fp->_IO_file_flags & _IO_NO_WRITES)
+        new_pos = fp->_IO_read_ptr - fp->_IO_read_base;
+      else
+        new_pos = fp->_IO_write_ptr - fp->_IO_write_base;
+    }
+  else
+    {
+      _IO_ssize_t cur_size = _IO_str_count(fp);
+      new_pos = EOF;
+
+      /* Move the get pointer, if requested. */
+      if (mode & _IOS_INPUT)
        {
-       case _IO_seek_end:
-         offset += cur_size;
-         break;
-       case _IO_seek_cur:
-         offset += fp->_IO_read_ptr - fp->_IO_read_base;
-         break;
-       default: /* case _IO_seek_set: */
-         break;
+         switch (dir)
+           {
+           case _IO_seek_end:
+             offset += cur_size;
+             break;
+           case _IO_seek_cur:
+             offset += fp->_IO_read_ptr - fp->_IO_read_base;
+             break;
+           default: /* case _IO_seek_set: */
+             break;
+           }
+         if (offset < 0 || (_IO_ssize_t)offset > cur_size)
+           return EOF;
+         fp->_IO_read_ptr = fp->_IO_read_base + offset;
+         fp->_IO_read_end = fp->_IO_read_base + cur_size;
+         new_pos = offset;
        }
-      if (offset < 0 || (_IO_ssize_t)offset > cur_size)
-       return EOF;
-      fp->_IO_read_ptr = fp->_IO_read_base + offset;
-      fp->_IO_read_end = fp->_IO_read_base + cur_size;
-      new_pos = offset;
-    }
 
-  /* Move the put pointer, if requested. */
-  if (mode & _IOS_OUTPUT)
-    {
-      switch (dir)
+      /* Move the put pointer, if requested. */
+      if (mode & _IOS_OUTPUT)
        {
-       case _IO_seek_end:
-         offset += cur_size;
-         break;
-       case _IO_seek_cur:
-         offset += fp->_IO_write_ptr - fp->_IO_write_base;
-         break;
-       default: /* case _IO_seek_set: */
-         break;
+         switch (dir)
+           {
+           case _IO_seek_end:
+             offset += cur_size;
+             break;
+           case _IO_seek_cur:
+             offset += fp->_IO_write_ptr - fp->_IO_write_base;
+             break;
+           default: /* case _IO_seek_set: */
+             break;
+           }
+         if (offset < 0 || (_IO_ssize_t)offset > cur_size)
+           return EOF;
+         fp->_IO_write_ptr = fp->_IO_write_base + offset;
+         new_pos = offset;
        }
-      if (offset < 0 || (_IO_ssize_t)offset > cur_size)
-       return EOF;
-      fp->_IO_write_ptr = fp->_IO_write_base + offset;
-      new_pos = offset;
     }
   return new_pos;
 }