LCOV - code coverage report
Current view: top level - lib/Support - xxhash.cpp (source / functions) Hit Total Coverage
Test: llvm-toolchain.info Lines: 29 29 100.0 %
Date: 2018-06-17 00:07:59 Functions: 1 1 100.0 %
Legend: Lines: hit not hit

          Line data    Source code
       1             : /*
       2             : *  xxHash - Fast Hash algorithm
       3             : *  Copyright (C) 2012-2016, Yann Collet
       4             : *
       5             : *  BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
       6             : *
       7             : *  Redistribution and use in source and binary forms, with or without
       8             : *  modification, are permitted provided that the following conditions are
       9             : *  met:
      10             : *
      11             : *  * Redistributions of source code must retain the above copyright
      12             : *  notice, this list of conditions and the following disclaimer.
      13             : *  * Redistributions in binary form must reproduce the above
      14             : *  copyright notice, this list of conditions and the following disclaimer
      15             : *  in the documentation and/or other materials provided with the
      16             : *  distribution.
      17             : *
      18             : *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
      19             : *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
      20             : *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
      21             : *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
      22             : *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
      23             : *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
      24             : *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
      25             : *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
      26             : *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
      27             : *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      28             : *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
      29             : *
      30             : *  You can contact the author at :
      31             : *  - xxHash homepage: http://www.xxhash.com
      32             : *  - xxHash source repository : https://github.com/Cyan4973/xxHash
      33             : */
      34             : 
      35             : /* based on revision d2df04efcbef7d7f6886d345861e5dfda4edacc1 Removed
      36             :  * everything but a simple interface for computing XXh64. */
      37             : 
      38             : #include "llvm/Support/xxhash.h"
      39             : #include "llvm/Support/Endian.h"
      40             : 
      41             : #include <stdlib.h>
      42             : #include <string.h>
      43             : 
      44             : using namespace llvm;
      45             : using namespace support;
      46             : 
      47             : static uint64_t rotl64(uint64_t X, size_t R) {
      48       11935 :   return (X << R) | (X >> (64 - R));
      49             : }
      50             : 
      51             : static const uint64_t PRIME64_1 = 11400714785074694791ULL;
      52             : static const uint64_t PRIME64_2 = 14029467366897019727ULL;
      53             : static const uint64_t PRIME64_3 = 1609587929392839161ULL;
      54             : static const uint64_t PRIME64_4 = 9650029242287828579ULL;
      55             : static const uint64_t PRIME64_5 = 2870177450012600261ULL;
      56             : 
      57             : static uint64_t round(uint64_t Acc, uint64_t Input) {
      58        9510 :   Acc += Input * PRIME64_2;
      59             :   Acc = rotl64(Acc, 31);
      60        9510 :   Acc *= PRIME64_1;
      61             :   return Acc;
      62             : }
      63             : 
      64             : static uint64_t mergeRound(uint64_t Acc, uint64_t Val) {
      65             :   Val = round(0, Val);
      66          36 :   Acc ^= Val;
      67          36 :   Acc = Acc * PRIME64_1 + PRIME64_4;
      68             :   return Acc;
      69             : }
      70             : 
      71        2265 : uint64_t llvm::xxHash64(StringRef Data) {
      72             :   size_t Len = Data.size();
      73             :   uint64_t Seed = 0;
      74             :   const char *P = Data.data();
      75        2265 :   const char *const BEnd = P + Len;
      76             :   uint64_t H64;
      77             : 
      78        2265 :   if (Len >= 32) {
      79           9 :     const char *const Limit = BEnd - 32;
      80             :     uint64_t V1 = Seed + PRIME64_1 + PRIME64_2;
      81             :     uint64_t V2 = Seed + PRIME64_2;
      82             :     uint64_t V3 = Seed + 0;
      83             :     uint64_t V4 = Seed - PRIME64_1;
      84             : 
      85             :     do {
      86             :       V1 = round(V1, endian::read64le(P));
      87             :       P += 8;
      88             :       V2 = round(V2, endian::read64le(P));
      89             :       P += 8;
      90             :       V3 = round(V3, endian::read64le(P));
      91             :       P += 8;
      92             :       V4 = round(V4, endian::read64le(P));
      93        1834 :       P += 8;
      94        1834 :     } while (P <= Limit);
      95             : 
      96          27 :     H64 = rotl64(V1, 1) + rotl64(V2, 7) + rotl64(V3, 12) + rotl64(V4, 18);
      97             :     H64 = mergeRound(H64, V1);
      98             :     H64 = mergeRound(H64, V2);
      99             :     H64 = mergeRound(H64, V3);
     100             :     H64 = mergeRound(H64, V4);
     101             : 
     102             :   } else {
     103             :     H64 = Seed + PRIME64_5;
     104             :   }
     105             : 
     106        2265 :   H64 += (uint64_t)Len;
     107             : 
     108        6541 :   while (P + 8 <= BEnd) {
     109             :     uint64_t const K1 = round(0, endian::read64le(P));
     110        2138 :     H64 ^= K1;
     111        2138 :     H64 = rotl64(H64, 27) * PRIME64_1 + PRIME64_4;
     112             :     P += 8;
     113             :   }
     114             : 
     115        2265 :   if (P + 4 <= BEnd) {
     116         126 :     H64 ^= (uint64_t)(endian::read32le(P)) * PRIME64_1;
     117         126 :     H64 = rotl64(H64, 23) * PRIME64_2 + PRIME64_3;
     118             :     P += 4;
     119             :   }
     120             : 
     121        2533 :   while (P < BEnd) {
     122         134 :     H64 ^= (*P) * PRIME64_5;
     123         134 :     H64 = rotl64(H64, 11) * PRIME64_1;
     124         134 :     P++;
     125             :   }
     126             : 
     127        2265 :   H64 ^= H64 >> 33;
     128        2265 :   H64 *= PRIME64_2;
     129        2265 :   H64 ^= H64 >> 29;
     130        2265 :   H64 *= PRIME64_3;
     131        2265 :   H64 ^= H64 >> 32;
     132             : 
     133        2265 :   return H64;
     134             : }

Generated by: LCOV version 1.13