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
diff --git a/include/ext/__hash b/include/ext/__hash
new file mode 100644
index 0000000..8e9635d
--- /dev/null
+++ b/include/ext/__hash
@@ -0,0 +1,46 @@
+// -*- 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
diff --git a/include/ext/hash_map b/include/ext/hash_map
index 21ce3be..9e62e7a 100644
--- a/include/ext/hash_map
+++ b/include/ext/hash_map
@@ -203,6 +203,7 @@
#include <__hash_table>
#include <functional>
#include <stdexcept>
+#include <ext/__hash>
#if __DEPRECATED
#warning Use of the header <ext/hash_map> is deprecated. Migrate to <unordered_map>
diff --git a/include/ext/hash_set b/include/ext/hash_set
index daad847..14daf7b 100644
--- a/include/ext/hash_set
+++ b/include/ext/hash_set
@@ -196,6 +196,7 @@
#include <__config>
#include <__hash_table>
#include <functional>
+#include <ext/__hash>
#if __DEPRECATED
#warning Use of the header <ext/hash_set> is deprecated. Migrate to <unordered_set>
@@ -205,7 +206,7 @@
using namespace std;
-template <class _Value, class _Hash = std::hash<_Value>, class _Pred = equal_to<_Value>,
+template <class _Value, class _Hash = hash<_Value>, class _Pred = equal_to<_Value>,
class _Alloc = allocator<_Value> >
class _LIBCPP_VISIBLE hash_set
{
diff --git a/include/string b/include/string
index d1b9a5e..8d48e0a 100644
--- a/include/string
+++ b/include/string
@@ -3857,6 +3857,21 @@
const typename basic_string<_CharT, _Traits, _Allocator>::size_type
basic_string<_CharT, _Traits, _Allocator>::npos;
+template<class _Ptr>
+size_t _LIBCPP_INLINE_VISIBILITY __do_string_hash(_Ptr __p, _Ptr __e)
+{
+ size_t __r = 0;
+ const size_t __sr = __CHAR_BIT__ * sizeof(size_t) - 8;
+ const size_t __m = size_t(0xF) << (__sr + 4);
+ for (; __p != __e; ++__p)
+ {
+ __r = (__r << 4) + *__p;
+ size_t __g = __r & __m;
+ __r ^= __g | (__g >> __sr);
+ }
+ return __r;
+}
+
template<class _CharT, class _Traits, class _Allocator>
struct _LIBCPP_VISIBLE hash<basic_string<_CharT, _Traits, _Allocator> >
: public unary_function<basic_string<_CharT, _Traits, _Allocator>, size_t>
@@ -3870,20 +3885,7 @@
hash<basic_string<_CharT, _Traits, _Allocator> >::operator()(
const basic_string<_CharT, _Traits, _Allocator>& __val) const _NOEXCEPT
{
- typedef basic_string<_CharT, _Traits, _Allocator> S;
- typedef typename S::const_pointer const_pointer;
- size_t __r = 0;
- const size_t __sr = __CHAR_BIT__ * sizeof(size_t) - 8;
- const size_t __m = size_t(0xF) << (__sr + 4);
- const_pointer __p = __val.data();
- const_pointer __e = __p + __val.size();
- for (; __p != __e; ++__p)
- {
- __r = (__r << 4) + *__p;
- size_t __g = __r & __m;
- __r ^= __g | (__g >> __sr);
- }
- return __r;
+ return __do_string_hash(__val.data(), __val.data() + __val.size());
}
template<class _CharT, class _Traits, class _Allocator>