cxx/include/ext/__hash
Sean Hunt affd9e5d43 Add a new hash class in __gnu_ext for the extension containers. There
are two motivations for this.

First, this allows users who are specializing __gnu_ext::hash to
continue doing so without changing their code.

Second, SGI specifies hash overloads for char* and const char* that
perform a hash of the string, not of the pointer.

In order to support this, the hashing code for string is factored out.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@136539 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-29 23:31:56 +00:00

47 lines
1.1 KiB
C++

// -*- C++ -*-
//===------------------------- hash_set ------------------------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP_EXT_HASH
#define _LIBCPP_EXT_HASH
#pragma GCC system_header
#include <string>
#include <cstring>
namespace __gnu_cxx {
using namespace std;
template <typename T> struct _LIBCPP_VISIBLE hash : public std::hash<T>
{ };
template <> struct _LIBCPP_VISIBLE hash<const char*>
: public unary_function<const char*, size_t>
{
_LIBCPP_INLINE_VISIBILITY
size_t operator()(const char *__c) const _NOEXCEPT
{
return __do_string_hash(__c, __c + strlen(__c));
}
};
template <> struct _LIBCPP_VISIBLE hash<char *>
: public unary_function<char*, size_t>
{
_LIBCPP_INLINE_VISIBILITY
size_t operator()(char *__c) const _NOEXCEPT
{
return __do_string_hash<const char *>(__c, __c + strlen(__c));
}
};
}
#endif _LIBCPP_EXT_HASH