gnulib/tests/test-wmemcmp.c

/* Test of wmemcmp() function.
   Copyright (C) 2008-2026 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>, 2023.  */

#include <config.h>

#include <wchar.h>

#include "signature.h"
SIGNATURE_CHECK (wmemcmp, int, (const wchar_t *, const wchar_t *, size_t));

#include "macros.h"

/* Test the prototype in <wchar.h> + compiler.  */
static int
null_wmemcmp (wchar_t const *ws1, wchar_t const *ws2, size_t n)
{
  int r = wmemcmp (ws1, ws2, n);
  ASSERT (ws1 == NULL);
  return r;
}
int (*volatile volatile_null_wmemcmp) (wchar_t const *, wchar_t const *, size_t)
  = null_wmemcmp;

/* Test the library, not the compiler+library.  */
static int
lib_wmemcmp (wchar_t const *ws1, wchar_t const *ws2, size_t n)
{
  return wmemcmp (ws1, ws2, n);
}
int (*volatile volatile_lib_wmemcmp) (wchar_t const *, wchar_t const *, size_t)
  = lib_wmemcmp;
#undef wmemcmp
#define wmemcmp volatile_lib_wmemcmp

int
main (int argc, char *argv[])
{
  /* Test equal / not equal distinction.  */
  {
    static const wchar_t input1[] = { 'f', 'o', 'o', 0 };
    static const wchar_t input2[] = { 'f', 'o', 'o', 'b', 'a', 'r', 0 };
    ASSERT (wmemcmp (input1, input2, 2) == 0);
    ASSERT (wmemcmp (input1, input2, 3) == 0);
    ASSERT (wmemcmp (input1, input2, 4) != 0);
  }
  {
    static const wchar_t input1[] = { 'f', 'o', 'o', 0 };
    static const wchar_t input2[] = { 'b', 'a', 'r', 0 };
    ASSERT (wmemcmp (input1, input2, 1) != 0);
    ASSERT (wmemcmp (input1, input2, 3) != 0);
  }

  /* Test less / equal / greater distinction.  */
  {
    static const wchar_t input1[] = { 'f', 'o', 'o', 0 };
    static const wchar_t input2[] = { 'm', 'o', 'o', 0 };
    ASSERT (wmemcmp (input1, input2, 4) < 0);
    ASSERT (wmemcmp (input2, input1, 4) > 0);
  }
  {
    static const wchar_t input1[] = { 'o', 'o', 'm', 'p', 'h', 0 };
    static const wchar_t input2[] = { 'o', 'o', 'p', 's', 0 };
    ASSERT (wmemcmp (input1, input2, 3) < 0);
    ASSERT (wmemcmp (input2, input1, 3) > 0);
  }
  {
    static const wchar_t input1[] = { 'f', 'o', 'o', 0 };
    static const wchar_t input2[] = { 'f', 'o', 'o', 'b', 'a', 'r', 0 };
    ASSERT (wmemcmp (input1, input2, 4) < 0);
    ASSERT (wmemcmp (input2, input1, 4) > 0);
  }

  /* ISO C requires wcscmp to work with all wchar_t values.
     ISO C 17 § 7.29.4.4 says:
       "Unless explicitly stated otherwise, the functions described in this
        subclause order two wide characters the same way as two integers of
        the underlying integer type designated by wchar_t."  */
  {
    const wchar_t input1[] = { (wchar_t) {0x76547654} };
    const wchar_t input2[] = { (wchar_t) {0x9abc9abc} };
    if ((wchar_t) {-1} < 0)
      {
        /* wchar_t is signed.  */
        ASSERT (wmemcmp (input1, input2, 1) > 0);
        ASSERT (wmemcmp (input2, input1, 1) < 0);
      }
    else
      {
        /* wchar_t is unsigned.  */
        ASSERT (wmemcmp (input1, input2, 1) < 0);
        ASSERT (wmemcmp (input2, input1, 1) > 0);
      }
  }
  {
    const wchar_t input1[] = { (wchar_t) {0x9abc9abc} };
    const wchar_t input2[] = { (wchar_t) {0x9bdf9bdf} };
    ASSERT (wmemcmp (input1, input2, 1) < 0);
    ASSERT (wmemcmp (input2, input1, 1) > 0);
  }

  /* Test zero-length operations on NULL pointers, allowed by
     <https://www.open-std.org/jtc1/sc22/wg14/www/docs/n3322.pdf>.  */
  ASSERT (wmemcmp (NULL, L"x", 0) == 0);
  ASSERT (wmemcmp (L"x", NULL, 0) == 0);
  ASSERT (wmemcmp (NULL, NULL, 0) == 0);

  ASSERT (volatile_null_wmemcmp (NULL, L"x", 0) == 0);

  return test_exit_status;
}