kernel / pub / scm / linux / kernel / git / jkacur / trace-cmd / refs/heads/trace-cmd-stable-v2.4 / . / trace-hash-local.h

/* | |

* Copyright (C) 2009, Steven Rostedt <srostedt@redhat.com> | |

* | |

* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |

* | |

* 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; version 2 of the License (not later!) | |

* | |

* 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 <http://www.gnu.org/licenses> | |

* | |

* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | |

*/ | |

#ifndef _TRACE_HASH_LOCAL_H | |

#define _TRACE_HASH_LOCAL_H | |

static inline unsigned int trace_hash(int val) | |

{ | |

int hash, tmp; | |

hash = 12546869; /* random prime */ | |

/* | |

* The following hash is based off of Paul Hsieh's super fast hash: | |

* http://www.azillionmonkeys.com/qed/hash.html | |

* Note, he released this code unde the GPL 2.0 license, which | |

* is the same as the license for the programs that use it here. | |

*/ | |

hash += (val & 0xffff); | |

tmp = (val >> 16) ^ hash; | |

hash = (hash << 16) ^ tmp; | |

hash += hash >> 11; | |

hash ^= hash << 3; | |

hash += hash >> 5; | |

hash ^= hash << 4; | |

hash += hash >> 17; | |

hash ^= hash << 25; | |

hash += hash >> 6; | |

return hash; | |

} | |

#endif /* _TRACE_HASH_LOCAL_H */ |