kc3-lang/gnulib/lib/next-prime.c

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• Hash : b5eb8780
  Author :
  Date : 2025-07-19T21:38:57
  

  next-prime: Tweaks for GNU gettext.
  
  * lib/next-prime.c (is_prime): Change so that is_prime (3) returns true.
  * tests/test-next-prime.c (main): Allow next_prime (1) to be 1.
  

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• lib/next-prime.c

• /* Finding the next prime >= a given small integer.
     Copyright (C) 1995-2025 Free Software Foundation, Inc.
  
     This file is free software: you can redistribute it and/or modify
     it under the terms of the GNU Lesser General Public License as
     published by the Free Software Foundation; either version 2.1 of the
     License, or (at your option) any later version.
  
     This file 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/>.  */
  
  #include <config.h>
  
  /* Specification.  */
  #include "next-prime.h"
  
  #include <stdint.h> /* for SIZE_MAX */
  
  /* Return true if CANDIDATE is a prime number or 1.
     CANDIDATE should be an odd number >= 1.  */
  static bool _GL_ATTRIBUTE_CONST
  is_prime (size_t candidate)
  {
    size_t divisor = 3;
    size_t square = divisor * divisor;
  
    for (;;)
      {
        if (square > candidate)
          return true;
        if ((candidate % divisor) == 0)
          return false;
        /* Increment divisor by 2.  */
        divisor++;
        square += 4 * divisor;
        divisor++;
      }
  }
  
  size_t _GL_ATTRIBUTE_CONST
  next_prime (size_t candidate)
  {
  #if !defined IN_LIBGETTEXTLIB
    /* Skip small primes.  */
    if (candidate < 10)
      candidate = 10;
  #endif
  
    /* Make it definitely odd.  */
    candidate |= 1;
  
    while (SIZE_MAX != candidate && !is_prime (candidate))
      candidate += 2;
  
    return candidate;
  }
  

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