include/llvm/Support/DJB.h

   1 //===-- llvm/Support/DJB.h ---DJB Hash --------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file contains support for the DJ Bernstein hash function.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef LLVM_SUPPORT_DJB_H
  14 #define LLVM_SUPPORT_DJB_H
  15
  16 #include "llvm/ADT/StringRef.h"
  17
  18 namespace llvm {
  19
  20 /// The Bernstein hash function used by the DWARF accelerator tables.
  21 inline uint32_t djbHash(StringRef Buffer, uint32_t H = 5381) {
  22   for (unsigned char C : Buffer.bytes())
  23     H = (H << 5) + H + C;
  24   return H;
  25 }
  26
  27 /// Computes the Bernstein hash after folding the input according to the Dwarf 5
  28 /// standard case folding rules.
  29 uint32_t caseFoldingDjbHash(StringRef Buffer, uint32_t H = 5381);
  30 } // namespace llvm
  31
  32 #endif // LLVM_SUPPORT_DJB_H