[llvm-commits] [llvm] r150890 - in /llvm/trunk: include/llvm/ADT/Hashing.h lib/Support/CMakeLists.txt lib/Support/Hashing.cpp unittests/ADT/HashingTest.cpp unittests/CMakeLists.txt

[Ahmed Charles]

On Sat, Feb 18, 2012 at 1:00 PM, Talin <viridia at gmail.com> wrote:
> Author: talin
> Date: Sat Feb 18 15:00:49 2012
> New Revision: 150890
>
> URL: http://llvm.org/viewvc/llvm-project?rev=150890&view=rev
> Log:
> Hashing.h - utilities for hashing various data types.
>
> --- llvm/trunk/lib/Support/Hashing.cpp (added)
> +++ llvm/trunk/lib/Support/Hashing.cpp Sat Feb 18 15:00:49 2012
> @@ -0,0 +1,46 @@
> +//===-- llvm/ADT/Hashing.cpp - Utilities for hashing ------------*- C++ -*-===//
> +//
> +//                     The LLVM Compiler Infrastructure
> +//
> +// This file is distributed under the University of Illinois Open Source
> +// License. See LICENSE.TXT for details.
> +//
> +//===----------------------------------------------------------------------===//
> +
> +#include "llvm/ADT/Hashing.h"
> +
> +namespace llvm {
> +
> +// Add a possibly unaligned sequence of bytes.
> +void GeneralHash::addUnaligned(const uint8_t *I, const uint8_t *E) {
> +  ptrdiff_t Length = E - I;
> +  if (uintptr_t(I) & 3 == 0) {

You probably want:

if ((uintptr_t(I) & 3) == 0) {

Right?

> +    while (Length > 3) {
> +      mix(*reinterpret_cast<const uint32_t *>(I));
> +      I += 4;
> +      Length -= 4;
> +    }
> +  } else {
> +    while (Length > 3) {
> +      mix(
> +        uint32_t(I[0]) +
> +        (uint32_t(I[1]) << 8) +
> +        (uint32_t(I[2]) << 16) +
> +        (uint32_t(I[3]) << 24));
> +      I += 4;
> +      Length -= 4;
> +    }
> +  }
> +
> +  if (Length & 3) {
> +    uint32_t Data = 0;
> +    switch (Length & 3) {
> +      case 3: Data |= uint32_t(I[2]) << 16;   // fall through
> +      case 2: Data |= uint32_t(I[1]) << 8;    // fall through
> +      case 1: Data |= uint32_t(I[0]); break;
> +    }
> +    mix(Data);
> +  }
> +}
> +
> +}
>