/* Optimized string comparison.
   Copyright (C) 2001-2002, 2007, 2009-2018 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or
   modify it under the terms of either:

     * the GNU Lesser General Public License as published by the Free
       Software Foundation; either version 3 of the License, or (at your
       option) any later version.

   or

     * the GNU General Public License as published by the Free
       Software Foundation; either version 2 of the License, or (at your
       option) any later version.

   or both in parallel, as here.
   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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible <bruno@clisp.org>.  */

#ifndef _GL_STREQ_H
#define _GL_STREQ_H

#include <string.h>

/* STREQ_OPT allows to optimize string comparison with a small literal string.
     STREQ_OPT (s, "EUC-KR", 'E', 'U', 'C', '-', 'K', 'R', 0, 0, 0)
   is semantically equivalent to
     strcmp (s, "EUC-KR") == 0
   just faster.  */

/* Help GCC to generate good code for string comparisons with
   immediate strings. */
#if defined (__GNUC__) && defined (__OPTIMIZE__)

static inline int
streq9 (const char *s1, const char *s2)
{
  return strcmp (s1 + 9, s2 + 9) == 0;
}

static inline int
streq8 (const char *s1, const char *s2, char s28)
{
  if (s1[8] == s28)
    {
      if (s28 == 0)
        return 1;
      else
        return streq9 (s1, s2);
    }
  else
    return 0;
}

static inline int
streq7 (const char *s1, const char *s2, char s27, char s28)
{
  if (s1[7] == s27)
    {
      if (s27 == 0)
        return 1;
      else
        return streq8 (s1, s2, s28);
    }
  else
    return 0;
}

static inline int
streq6 (const char *s1, const char *s2, char s26, char s27, char s28)
{
  if (s1[6] == s26)
    {
      if (s26 == 0)
        return 1;
      else
        return streq7 (s1, s2, s27, s28);
    }
  else
    return 0;
}

static inline int
streq5 (const char *s1, const char *s2, char s25, char s26, char s27, char s28)
{
  if (s1[5] == s25)
    {
      if (s25 == 0)
        return 1;
      else
        return streq6 (s1, s2, s26, s27, s28);
    }
  else
    return 0;
}

static inline int
streq4 (const char *s1, const char *s2, char s24, char s25, char s26, char s27, char s28)
{
  if (s1[4] == s24)
    {
      if (s24 == 0)
        return 1;
      else
        return streq5 (s1, s2, s25, s26, s27, s28);
    }
  else
    return 0;
}

static inline int
streq3 (const char *s1, const char *s2, char s23, char s24, char s25, char s26, char s27, char s28)
{
  if (s1[3] == s23)
    {
      if (s23 == 0)
        return 1;
      else
        return streq4 (s1, s2, s24, s25, s26, s27, s28);
    }
  else
    return 0;
}

static inline int
streq2 (const char *s1, const char *s2, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
{
  if (s1[2] == s22)
    {
      if (s22 == 0)
        return 1;
      else
        return streq3 (s1, s2, s23, s24, s25, s26, s27, s28);
    }
  else
    return 0;
}

static inline int
streq1 (const char *s1, const char *s2, char s21, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
{
  if (s1[1] == s21)
    {
      if (s21 == 0)
        return 1;
      else
        return streq2 (s1, s2, s22, s23, s24, s25, s26, s27, s28);
    }
  else
    return 0;
}

static inline int
streq0 (const char *s1, const char *s2, char s20, char s21, char s22, char s23, char s24, char s25, char s26, char s27, char s28)
{
  if (s1[0] == s20)
    {
      if (s20 == 0)
        return 1;
      else
        return streq1 (s1, s2, s21, s22, s23, s24, s25, s26, s27, s28);
    }
  else
    return 0;
}

#define STREQ_OPT(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \
  streq0 (s1, s2, s20, s21, s22, s23, s24, s25, s26, s27, s28)

#else

#define STREQ_OPT(s1,s2,s20,s21,s22,s23,s24,s25,s26,s27,s28) \
  (strcmp (s1, s2) == 0)

#endif

#endif /* _GL_STREQ_H */
