1 //===-- llvm/ADT/Hashing.cpp - Utilities for hashing ------------*- C++ -*-===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "llvm/ADT/Hashing.h"
11 
12 namespace llvm {
13 
14 // Add a possibly unaligned sequence of bytes.
15 void GeneralHash::addUnaligned(const uint8_t *I, const uint8_t *E) {
16   ptrdiff_t Length = E - I;
17   if (uintptr_t(I) & 3 == 0) {
18     while (Length > 3) {
19       mix(*reinterpret_cast<const uint32_t *>(I));
20       I += 4;
21       Length -= 4;
22     }
23   } else {
24     while (Length > 3) {
25       mix(
26         uint32_t(I[0]) +
27         (uint32_t(I[1]) << 8) +
28         (uint32_t(I[2]) << 16) +
29         (uint32_t(I[3]) << 24));
30       I += 4;
31       Length -= 4;
32     }
33   }
34 
35   if (Length & 3) {
36     uint32_t Data = 0;
37     switch (Length & 3) {
38       case 3: Data |= uint32_t(I[2]) << 16;   // fall through
39       case 2: Data |= uint32_t(I[1]) << 8;    // fall through
40       case 1: Data |= uint32_t(I[0]); break;
41     }
42     mix(Data);
43   }
44 }
45 
46 }
47