/*

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

   | Copyright (c) The PHP Group                                          |

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

   | This source file is subject to version 3.01 of the PHP license,      |

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

   | available through the world-wide-web at the following url:           |

   | http://www.php.net/license/3_01.txt                                  |

   | If you did not receive a copy of the PHP license and are unable to   |

   | obtain it through the world-wide-web, please send a note to          |

   | license@php.net so we can mail you a copy immediately.               |

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

   | Author: Rasmus Lerdorf <rasmus@php.net>                              |

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

*/

#include "php.h"

#include "basic_functions.h"

#include "crc32.h"

#if HAVE_AARCH64_CRC32

# include <arm_acle.h>

# if defined(__linux__)

#  include <sys/auxv.h>

#  include <asm/hwcap.h>

# endif

static inline int has_crc32_insn() {

  /* Only go through the runtime detection once. */

  static int res = -1;

  if (res != -1)

    return res;

# if defined(HWCAP_CRC32)

  res = getauxval(AT_HWCAP) & HWCAP_CRC32;

  return res;

# elif defined(HWCAP2_CRC32)

  res = getauxval(AT_HWCAP2) & HWCAP2_CRC32;

  return res;

# else

  res = 0;

  return res;

# endif

}

# pragma GCC push_options

# pragma GCC target ("+nothing+crc")

static uint32_t crc32_aarch64(uint32_t crc, char *p, size_t nr) {

  while (nr >= sizeof(uint64_t)) {

    crc = __crc32d(crc, *(uint64_t *)p);

    p += sizeof(uint64_t);

    nr -= sizeof(uint64_t);

  }

  if (nr >= sizeof(int32_t)) {

    crc = __crc32w(crc, *(uint32_t *)p);

    p += sizeof(uint32_t);

    nr -= sizeof(uint32_t);

  }

  if (nr >= sizeof(int16_t)) {

    crc = __crc32h(crc, *(uint16_t *)p);

    p += sizeof(uint16_t);

    nr -= sizeof(uint16_t);

  }

  if (nr) {

    crc = __crc32b(crc, *p);

  }

  return crc;

}

# pragma GCC pop_options

#endif

/* {{{ Calculate the crc32 polynomial of a string */

PHP_FUNCTION(crc32)

{

  char *p;

  size_t nr;

  uint32_t crcinit = 0;

  register uint32_t crc;

  ZEND_PARSE_PARAMETERS_START(1, 1)

    Z_PARAM_STRING(p, nr)

  ZEND_PARSE_PARAMETERS_END();

  crc = crcinit^0xFFFFFFFF;

#if HAVE_AARCH64_CRC32

  if (has_crc32_insn()) {

    crc = crc32_aarch64(crc, p, nr);

    RETURN_LONG(crc^0xFFFFFFFF);

  }

#endif

  for (; nr--; ++p) {

    crc = ((crc >> 8) & 0x00FFFFFF) ^ crc32tab[(crc ^ (*p)) & 0xFF ];

  }

  RETURN_LONG(crc^0xFFFFFFFF);

}

/* }}} */