/*

  +----------------------------------------------------------------------+

  | Copyright © The PHP Group and Contributors.                          |

  +----------------------------------------------------------------------+

  | This source file is subject to the Modified BSD License that is      |

  | bundled with this package in the file LICENSE, and is available      |

  | through the World Wide Web at <https://www.php.net/license/>.        |

  |                                                                      |

  | SPDX-License-Identifier: BSD-3-Clause                                |

  +----------------------------------------------------------------------+

  | Author: David Carlier <devnexen@gmail.com>                           |

  +----------------------------------------------------------------------+

*/

#include "php.h"

#include <string.h>

/*

 * Returns 0 if both inputs match, non-zero if they don't.

 * Returns -1 early if inputs do not have the same lengths.

 *

 */

PHPAPI int php_safe_bcmp(const zend_string *a, const zend_string *b)

{

  const volatile unsigned char *ua = (const volatile unsigned char *)ZSTR_VAL(a);

  const volatile unsigned char *ub = (const volatile unsigned char *)ZSTR_VAL(b);

  size_t i = 0;

  int r = 0;

  if (ZSTR_LEN(a) != ZSTR_LEN(b)) {

    return -1;

  }

  /* This is security sensitive code. Do not optimize this for speed. */

  while (i < ZSTR_LEN(a)) {

    r |= ua[i] ^ ub[i];

    ++i;

  }

  return r;

}