Imported Upstream version 1.4.19

[platform/upstream/m4.git] / lib / ftello.c

diff --git a/lib/ftello.c b/lib/ftello.c
index 4c18ed1..da13694 100644 (file)
--- a/lib/ftello.c
+++ b/lib/ftello.c
@@ -1,5 +1,5 @@
 /* An ftello() function that works around platform bugs.
-   Copyright (C) 2007, 2009-2016 Free Software Foundation, Inc.
+   Copyright (C) 2007, 2009-2021 Free Software Foundation, Inc.
 
    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -12,13 +12,16 @@
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 
 /* Specification.  */
 #include <stdio.h>
 
+#include <errno.h>
+#include "intprops.h"
+
 /* Get lseek.  */
 #include <unistd.h>
 
@@ -40,13 +43,79 @@ ftello (FILE *fp)
 # endif
 #endif
 {
-#if LSEEK_PIPE_BROKEN
+#if FTELLO_BROKEN_AFTER_UNGETC /* macOS >= 10.15 */
+  /* The system's ftello() is completely broken, because it calls __sflush,
+     which makes side effects on the stream.  */
+
+  /* Handle non-seekable files first.  */
+  if (fp->_file < 0 || fp->_seek == NULL)
+    {
+      errno = ESPIPE;
+      return -1;
+    }
+
+  /* Determine the current offset, ignoring buffered and pushed-back bytes.  */
+  off_t pos;
+
+  if (fp->_flags & __SOFF)
+    pos = fp->_offset;
+  else
+    {
+      pos = fp->_seek (fp->_cookie, 0, SEEK_CUR);
+      if (pos < 0)
+        return -1;
+      if (fp->_flags & __SOPT)
+        {
+          fp->_offset = pos;
+          fp->_flags |= __SOFF;
+        }
+    }
+
+  if (fp->_flags & __SRD)
+    {
+      /* Now consider buffered and pushed-back bytes from ungetc.  */
+      if (fp->_ub._base != NULL)
+        /* Considering the buffered bytes, we are at position
+             pos - fp->_ur.
+           Considering also the pushed-back bytes, we are at position
+             pos - fp->_ur - fp->_r.  */
+        pos = pos - fp->_ur - fp->_r;
+      else
+        /* Considering the buffered bytes, we are at position
+             pos - fp->_r.  */
+        pos = pos - fp->_r;
+      if (pos < 0)
+        {
+          errno = EIO;
+          return -1;
+        }
+    }
+  else if ((fp->_flags & __SWR) && fp->_p != NULL)
+    {
+      /* Consider the buffered bytes.  */
+      off_t buffered = fp->_p - fp->_bf._base;
+
+      /* Compute pos + buffered, with overflow check.  */
+      off_t sum;
+      if (! INT_ADD_OK (pos, buffered, &sum))
+        {
+          errno = EOVERFLOW;
+          return -1;
+        }
+      pos = sum;
+    }
+
+  return pos;
+
+#else
+
+# if LSEEK_PIPE_BROKEN
   /* mingw gives bogus answers rather than failure on non-seekable files.  */
   if (lseek (fileno (fp), 0, SEEK_CUR) == -1)
     return -1;
-#endif
+# endif
 
-#if FTELLO_BROKEN_AFTER_SWITCHING_FROM_READ_TO_WRITE /* Solaris */
+# if FTELLO_BROKEN_AFTER_SWITCHING_FROM_READ_TO_WRITE /* Solaris */
   /* The Solaris stdio leaves the _IOREAD flag set after reading from a file
      reaches EOF and the program then starts writing to the file.  ftello
      gets confused by this.  */
@@ -66,9 +135,9 @@ ftello (FILE *fp)
         }
       return pos;
     }
-#endif
+# endif
 
-#if defined __SL64 && defined __SCLE /* Cygwin */
+# if defined __SL64 && defined __SCLE /* Cygwin */
   if ((fp->_flags & __SL64) == 0)
     {
       /* Cygwin 1.5.0 through 1.5.24 failed to open stdin in 64-bit
@@ -80,6 +149,9 @@ ftello (FILE *fp)
       fp->_seek64 = tmp->_seek64;
       fclose (tmp);
     }
-#endif
+# endif
+
   return ftello (fp);
+
+#endif
 }