On 19 November 2012 21:35, Jonathan Wakely wrote:
> * include/bits/hashtable.h: Improve comments.
> * include/bits/hashtable_policy.h: Likewise.
>
> Tested x86_64-linux, committed to trunk.
Attached version committed to the 4.7 branch.
commit 8db4c698a78df8c150ea3353aaed254448620fba
Author: Jonathan Wakely <jwakely....@gmail.com>
Date: Mon Feb 18 21:06:08 2013 +0000
* include/bits/hashtable.h: Improve comments.
* include/bits/hashtable_policy.h: Likewise.
diff --git a/libstdc++-v3/include/bits/hashtable.h
b/libstdc++-v3/include/bits/hashtable.h
index b58189f..c7a8be0 100644
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -1,6 +1,7 @@
// hashtable.h header -*- C++ -*-
-// Copyright (C) 2007-2012 Free Software Foundation, Inc.
+// Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013
+// Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
@@ -98,43 +99,44 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
* - size_type _M_bucket_count
* - size_type _M_element_count
*
- * with _Bucket being _Hash_node* and _Hash_node constaining:
+ * with _Bucket being _Hash_node* and _Hash_node containing:
* - _Hash_node* _M_next
* - Tp _M_value
- * - size_t _M_code if cache_hash_code is true
+ * - size_t _M_hash_code if cache_hash_code is true
*
- * In terms of Standard containers the hastable is like the aggregation of:
+ * In terms of Standard containers the hashtable is like the aggregation of:
* - std::forward_list<_Node> containing the elements
* - std::vector<std::forward_list<_Node>::iterator> representing the buckets
*
- * The non-empty buckets contain the node before the first bucket node. This
- * design allow to implement something like a std::forward_list::insert_after
- * on container insertion and std::forward_list::erase_after on container
- * erase calls. _M_before_begin is equivalent to
- * std::foward_list::before_begin. Empty buckets are containing nullptr.
- * Note that one of the non-empty bucket contains &_M_before_begin which is
- * not a derefenrenceable node so the node pointers in buckets shall never be
- * derefenrenced, only its next node can be.
+ * The non-empty buckets contain the node before the first node in the
+ * bucket. This design makes it possible to implement something like a
+ * std::forward_list::insert_after on container insertion and
+ * std::forward_list::erase_after on container erase calls.
+ * _M_before_begin is equivalent to std::foward_list::before_begin.
+ * Empty buckets contain nullptr.
+ * Note that one of the non-empty buckets contains &_M_before_begin which is
+ * not a dereferenceable node so the node pointer in a bucket shall never be
+ * dereferenced, only its next node can be.
*
- * Walk through a bucket nodes require a check on the hash code to see if the
- * node is still in the bucket. Such a design impose a quite efficient hash
- * functor and is one of the reasons it is highly advise to set
- * __cache_hash_code to true.
+ * Walking through a bucket's nodes requires a check on the hash code to see
+ * if each node is still in the bucket. Such a design assumes a quite
+ * efficient hash functor and is one of the reasons it is
+ * highly advisable to set __cache_hash_code to true.
*
* The container iterators are simply built from nodes. This way incrementing
* the iterator is perfectly efficient independent of how many empty buckets
* there are in the container.
*
- * On insert we compute element hash code and thanks to it find the bucket
- * index. If the element must be inserted on an empty bucket we add it at the
- * beginning of the singly linked list and make the bucket point to
+ * On insert we compute the element's hash code and use it to it find the
+ * bucket index. If the element must be inserted in an empty bucket we add
+ * it at the beginning of the singly linked list and make the bucket point to
* _M_before_begin. The bucket that used to point to _M_before_begin, if any,
* is updated to point to its new before begin node.
*
- * On erase, the simple iterator design impose to use the hash functor to get
- * the index of the bucket to update. For this reason, when __cache_hash_code
- * is set to false, there is a static assertion that the hash functor cannot
- * throw.
+ * On erase, the simple iterator design requires using the hash functor to
+ * get the index of the bucket to update. For this reason, when
+ * __cache_hash_code is set to false, the hash functor must not throw
+ * and this is enforced by a statied assertion.
*/
template<typename _Key, typename _Value, typename _Allocator,
@@ -981,7 +983,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
else if (__result)
// All equivalent values are next to each other, if we found a not
// equivalent value after an equivalent one it means that we won't
- // find anymore an equivalent value.
+ // find any more equivalent values.
break;
if (!__p->_M_nxt || _M_bucket_index(__p->_M_next()) != __n)
break;
@@ -1103,7 +1105,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
else
{
// The bucket is empty, the new node is inserted at the beginning of
- // the singly linked list and the bucket will contain _M_before_begin
+ // the singly-linked list and the bucket will contain _M_before_begin
// pointer.
__new_node->_M_nxt = _M_before_begin._M_nxt;
_M_before_begin._M_nxt = __new_node;
@@ -1251,7 +1253,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
else
// The inserted node has no equivalent in the hashtable. We must
// insert the new node at the beginning of the bucket to preserve
- // equivalent elements relative positions.
+ // equivalent elements' relative positions.
_M_insert_bucket_begin(__bkt, __new_node);
++_M_element_count;
return iterator(__new_node);
@@ -1433,7 +1435,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
std::size_t __bkt = _M_bucket_index(__n);
// Look for previous node to unlink it from the erased one, this is why
- // we need buckets to contain the before begin to make this research
fast.
+ // we need buckets to contain the before begin to make this search fast.
_BaseNode* __prev_n = _M_get_previous_node(__bkt, __n);
if (__n == _M_bucket_begin(__bkt))
_M_remove_bucket_begin(__bkt, __n->_M_next(),
diff --git a/libstdc++-v3/include/bits/hashtable_policy.h
b/libstdc++-v3/include/bits/hashtable_policy.h
index 631128a..2359e93 100644
--- a/libstdc++-v3/include/bits/hashtable_policy.h
+++ b/libstdc++-v3/include/bits/hashtable_policy.h
@@ -59,8 +59,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return __distance_fw(__first, __last, _Tag());
}
- // Helper type used to detect when the hash functor is noexcept qualified or
- // not
+ // Helper type used to detect whether the hash functor is noexcept.
template <typename _Key, typename _Hash>
struct __is_noexcept_hash : std::integral_constant<bool,
noexcept(declval<const _Hash&>()(declval<const _Key&>()))>
