[range] - merge the tested changes from the trunk in preparation for the 1.46 release.

[SVN r67905]

doc/reference/adaptors/strided.qbk

@@ -11,7 +11,7 @@
     [[Function] [`boost::adaptors::stride(rng, n)`]]
 ]
 
-* [*Precondition:] `0 <= n` and `boost::size(rng)` is a valid expression.
+* [*Precondition:] `0 <= n`.
 * [*Returns:] A new range based on `rng` where traversal is performed in steps of `n`.
 * [*Range Category:] __single_pass_range__
 * [*Returned Range Category:] The range category of `rng`.

doc/reference/adaptors/type_erased.qbk

@@ -0,0 +1,151 @@
+[/
+    Copyright 2010 Neil Groves
+    Distributed under the Boost Software License, Version 1.0.
+    (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+/]
+[section:type_erased type_erased]
+
+[table
+    [[Syntax] [Code]]
+    [[Pipe] [`rng | boost::adaptors::type_erased<Value, Traversal, Reference, Difference, Buffer>()`]]
+    [[Function] [`boost::adaptors::type_erase(rng, boost::adaptors::type_erased<Value, Traversal, Reference, Difference, Buffer>)`]]
+]
+
+Please note that it is frequently unnecessary to use the `type_erased` adaptor. It is often better to use the implicit conversion to `any_range`.
+
+Let `Rng` be the type of `rng`.
+
+* [*Template parameters:]
+    * `Value` is the `value_type` for the `any_range`. If this is set to boost::use_default, `Value` will be calculated from the
+        range type when the adaptor is applied.
+    * `Traversal` is the tag used to identify the traversal of the resultant range. Frequently it is desireable to set a traversal category lower than the source container or range to maximize the number of ranges that can convert to the `any_range`. If this is left as boost::use_default then `Traversal` will be `typename boost::iterator_traversal<boost::range_iterator<Rng>::type>::type`
+    * `Reference` is the `reference` for the `any_range`. `boost::use_default` will equate to `typename range_reference<Rng>::type`.
+    * `Difference` is the `difference_type` for the any_range. `boost::use_default` will equate to `typename boost::range_difference<Rng>::type`
+    * `Buffer` is the storage used to allocate the underlying iterator wrappers. This can typically be ignored, but is available as a template parameter for customization. Buffer must be a model of the `AnyIteratorBufferConcept`.
+* [*Precondition:]  `Traversal` is one of `{ boost::use_default, boost::single_pass_traversal_tag, boost::forward_traversal_tag, boost::bidirectional_traversal_tag, boost::random_access_traversal_tag }`
+* [*Returns:] The returned value is the same as `typename any_range_type_generator< Rng, Value, Traversal, Reference, Difference, Buffer >` that represents `rng` in a type-erased manner.
+* [*Range Category:] __single_pass_range__
+* [*Returned Range Category:] if `Traversal` was specified as `boost::use_default` then `typename boost::iterator_traversal<boost::range_iterator<Rng>::type>::type`, otherwise `Traversal`.
+
+[heading AnyIteratorBufferConcept]
+``
+class AnyIteratorBufferConcept
+{
+public:
+    AnyIteratorBufferConcept();
+    ~AnyIteratorBufferConcept();
+
+    // bytes is the requested size to allocate. This function
+    // must return a pointer to an adequate area of memory.
+    // throws: bad_alloc
+    //
+    // The buffer will only ever have zero or one
+    // outstanding memory allocations.
+    void* allocate(std::size_t bytes);
+
+    // deallocate this buffer
+    void deallocate();
+};
+``
+
+[section:type_erased_example type-erased example]
+``
+#include <boost/range/adaptor/type_erased.hpp>
+#include <boost/range/algorithm/copy.hpp>
+#include <boost/assign.hpp>
+#include <boost/foreach.hpp>
+#include <algorithm>
+#include <iostream>
+#include <list>
+#include <vector>
+
+// The client interface from an OO perspective merely requires a sequence
+// of integers that can be forward traversed
+typedef boost::any_range<
+    int
+  , boost::forward_traversal_tag
+  , int
+  , std::ptrdiff_t
+> integer_range;
+
+namespace server
+{
+    void display_integers(const integer_range& rng)
+    {
+        boost::copy(rng,
+                    std::ostream_iterator<int>(std::cout, ","));
+
+        std::cout << std::endl;
+    }
+}
+
+namespace client
+{
+    void run()
+    {
+        using namespace boost::assign;
+        using namespace boost::adaptors;
+
+        // Under most conditions one would simply use an appropriate
+        // any_range as a function parameter. The type_erased adaptor
+        // is often superfluous. However because the type_erased
+        // adaptor is applied to a range, we can use default template
+        // arguments that are generated in conjunction with the
+        // range type to which we are applying the adaptor.
+
+        std::vector<int> input;
+        input += 1,2,3,4,5;
+
+        // Note that this call is to a non-template function
+        server::display_integers(input);
+
+        std::list<int> input2;
+        input2 += 6,7,8,9,10;
+
+        // Note that this call is to the same non-tempate function
+        server::display_integers(input2);
+
+        input2.clear();
+        input2 += 11,12,13,14,15;
+
+        // Calling using the adaptor looks like this:
+        // Notice that here I have a type_erased that would be a
+        // bidirectional_traversal_tag, but this is convertible
+        // to the forward_traversal_tag equivalent hence this
+        // works.
+        server::display_integers(input2 | type_erased<>());
+
+        // However we may simply wish to define an adaptor that
+        // takes a range and makes it into an appropriate
+        // forward_traversal any_range...
+        typedef boost::adaptors::type_erased<
+            boost::use_default
+          , boost::forward_traversal_tag
+        > type_erased_forward;
+
+        // This adaptor can turn other containers with different
+        // value_types and reference_types into the appropriate
+        // any_range.
+
+        server::display_integers(input2 | type_erased_forward());
+    }
+}
+
+int main(int argc, const char* argv[])
+{
+    client::run();
+    return 0;
+}
+``
+[endsect]
+
+This would produce the output:
+``
+1,2,3,4,5
+6,7,8,9,10
+11,12,13,14,15
+11,12,13,14,15
+``
+[endsect]
+
+