1 files changed, 130 insertions, 0 deletions
diff --git a/gnulib-tests/test-freading.c b/gnulib-tests/test-freading.c
new file mode 100644
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--- /dev/null
+++ b/gnulib-tests/test-freading.c
@@ -0,0 +1,130 @@
+/* Test of freading() function.
+   Copyright (C) 2007-2022 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
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   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 <https://www.gnu.org/licenses/>.  */
+
+/* Written by Bruno Haible <bruno@clisp.org>, 2007.  */
+
+#include <config.h>
+
+/* None of the files accessed by this test are large, so disable the
+   fseek link warning if we are not using the gnulib fseek module.  */
+#define _GL_NO_LARGE_FILES
+#include "freading.h"
+
+#include <stdio.h>
+
+#include "macros.h"
+
+#define TESTFILE "t-freading.tmp"
+
+int
+main (void)
+{
+  FILE *fp;
+
+  /* Create a file with some contents.  Write-only file is never reading.  */
+  fp = fopen (TESTFILE, "w");
+  ASSERT (fp);
+  ASSERT (!freading (fp));
+  ASSERT (fwrite ("foobarsh", 1, 8, fp) == 8);
+  ASSERT (!freading (fp));
+  ASSERT (fclose (fp) == 0);
+
+  /* Open it in read-only mode.  Read-only file is always reading.  */
+  fp = fopen (TESTFILE, "r");
+  ASSERT (fp);
+  ASSERT (freading (fp));
+  ASSERT (fgetc (fp) == 'f');
+  ASSERT (freading (fp));
+  ASSERT (fseek (fp, 2, SEEK_CUR) == 0);
+  ASSERT (freading (fp));
+  ASSERT (fgetc (fp) == 'b');
+  ASSERT (freading (fp));
+  fflush (fp);
+  ASSERT (freading (fp));
+  ASSERT (fgetc (fp) == 'a');
+  ASSERT (freading (fp));
+  ASSERT (fseek (fp, 0, SEEK_END) == 0);
+  ASSERT (freading (fp));
+  ASSERT (fclose (fp) == 0);
+
+  /* Open it in read-write mode.  POSIX requires a reposition (fseek,
+     fsetpos, rewind) or EOF when transitioning from read to write;
+     freading is only deterministic after input or output, but this
+     test case should be portable even on open, after reposition, and
+     at EOF.  */
+  /* First a scenario with only fgetc, fseek, fputc.  */
+  fp = fopen (TESTFILE, "r+");
+  ASSERT (fp);
+  ASSERT (!freading (fp));
+  ASSERT (fgetc (fp) == 'f');
+  ASSERT (freading (fp));
+  ASSERT (fseek (fp, 2, SEEK_CUR) ==  0);
+  /* freading (fp) is undefined here, but fwriting (fp) is false.  */
+  ASSERT (fgetc (fp) == 'b');
+  ASSERT (freading (fp));
+  /* This fseek call is necessary when switching from reading to writing.
+     See the description of fopen(), ISO C 99 7.19.5.3.(6).  */
+  ASSERT (fseek (fp, 0, SEEK_CUR) == 0);
+  /* freading (fp) is undefined here, but fwriting (fp) is false.  */
+  ASSERT (fputc ('x', fp) == 'x');
+  ASSERT (!freading (fp));
+  ASSERT (fseek (fp, 0, SEEK_END) == 0);
+  /* freading (fp) is undefined here, because on some implementations (e.g.
+     glibc) fseek causes a buffer to be read.
+     fwriting (fp) is undefined as well.  */
+  ASSERT (fclose (fp) == 0);
+
+  /* Open it in read-write mode.  POSIX requires a reposition (fseek,
+     fsetpos, rewind) or EOF when transitioning from read to write;
+     freading is only deterministic after input or output, but this
+     test case should be portable even on open, after reposition, and
+     at EOF.  */
+  /* Here a scenario that includes fflush.  */
+  fp = fopen (TESTFILE, "r+");
+  ASSERT (fp);
+  ASSERT (!freading (fp));
+  ASSERT (fgetc (fp) == 'f');
+  ASSERT (freading (fp));
+  ASSERT (fseek (fp, 2, SEEK_CUR) == 0);
+  /* freading (fp) is undefined here, but fwriting (fp) is false.  */
+  ASSERT (fgetc (fp) == 'b');
+  ASSERT (freading (fp));
+  fflush (fp);
+  /* freading (fp) is undefined here, but fwriting (fp) is false.  */
+  ASSERT (fgetc (fp) == 'x');
+  ASSERT (freading (fp));
+  /* This fseek call is necessary when switching from reading to writing.
+     See the description of fopen(), ISO C 99 7.19.5.3.(6).  */
+  ASSERT (fseek (fp, 0, SEEK_CUR) == 0);
+  /* freading (fp) is undefined here, but fwriting (fp) is false.  */
+  ASSERT (fputc ('z', fp) == 'z');
+  ASSERT (!freading (fp));
+  ASSERT (fseek (fp, 0, SEEK_END) == 0);
+  /* freading (fp) is undefined here, because on some implementations (e.g.
+     glibc) fseek causes a buffer to be read.
+     fwriting (fp) is undefined as well.  */
+  ASSERT (fclose (fp) == 0);
+
+  /* Open it in append mode.  Write-only file is never reading.  */
+  fp = fopen (TESTFILE, "a");
+  ASSERT (fp);
+  ASSERT (!freading (fp));
+  ASSERT (fwrite ("bla", 1, 3, fp) == 3);
+  ASSERT (!freading (fp));
+  ASSERT (fclose (fp) == 0);
+  ASSERT (remove (TESTFILE) == 0);
+  return 0;
+}