Refactor stream write functionality into a standalone utility

Make string_view operator<< use rdbuf directly

appveyor.yml

@@ -1,4 +1,4 @@
-# Copyright 2016, 2017 Peter Dimov
+# Copyright 2016-2019 Peter Dimov
 # Distributed under the Boost Software License, Version 1.0.
 # (See accompanying file LICENSE_1_0.txt or copy at http://boost.org/LICENSE_1_0.txt)
 
@@ -14,12 +14,14 @@ branches:
 
 environment:
   matrix:
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
-      TOOLSET: msvc-9.0,msvc-10.0,msvc-11.0,msvc-12.0
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
-      TOOLSET: msvc-14.0
+      TOOLSET: msvc-9.0,msvc-10.0,msvc-11.0
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
+      TOOLSET: msvc-12.0,msvc-14.0
+      ADDRMD: 32,64
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
       TOOLSET: msvc-14.1
+      ADDRMD: 32,64
       CXXSTD: 14,17
 
 install:
@@ -43,7 +45,7 @@ install:
   - git submodule init libs/integer
   - git submodule init libs/detail
   - git submodule update --jobs %GIT_FETCH_JOBS%
-  - xcopy /s /e /q %APPVEYOR_BUILD_FOLDER% libs\utility
+  - xcopy /s /e /q %APPVEYOR_BUILD_FOLDER% libs\utility\
   - cmd /c bootstrap
   - b2 -d0 headers
 
@@ -52,4 +54,5 @@ build: off
 test_script:
   - PATH=%ADDPATH%%PATH%
   - if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
-  - b2 -j %NUMBER_OF_PROCESSORS% libs/utility/test toolset=%TOOLSET% %CXXSTD%
+  - if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
+  - b2 -j %NUMBER_OF_PROCESSORS% libs/utility/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release

doc/Jamfile.v2

@@ -99,6 +99,19 @@ boostbook standalone_declval
         <xsl:param>generate.section.toc.level=1
      ;
 
+xml ostream_string : ostream_string.qbk ;
+boostbook standalone_ostream_string
+    :
+        ostream_string
+    :
+        <xsl:param>root.filename=ostream_string
+        <xsl:param>chunk.section.depth=0
+        <xsl:param>chunk.first.sections=0
+        <xsl:param>toc.section.depth=1
+        <xsl:param>toc.max.depth=1
+        <xsl:param>generate.section.toc.level=1
+     ;
+
 xml string_ref : string_ref.qbk ;
 boostbook standalone_string_ref
     :
@@ -123,5 +136,5 @@ alias boostdoc ;
 explicit boostdoc ;
 alias boostrelease :
     standalone_base_from_member standalone_compressed_pair
-    standalone_declval standalone_string_ref ;
+    standalone_declval standalone_ostream_string standalone_string_ref ;
 explicit boostrelease ;

doc/ostream_string.qbk

@@ -0,0 +1,62 @@
+[/
+Copyright 2019 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+]
+
+[article ostream_string
+[quickbook 1.5]
+[authors [Fernandes, Glen]]
+[copyright 2019 Glen Joseph Fernandes]
+[license Distributed under the Boost Software License, Version 1.0.]]
+
+[section Overview]
+
+The header <boost/utility/ostream_string.hpp> provides the function template
+boost::ostream_string for formatted output that satisfies the requirements of
+\[ostream.formatted.reqmts\].
+
+[endsect]
+
+[section Examples]
+
+The inserter for class template `basic_string_view` could be implemented as
+follows:
+
+```
+template<class charT, class traits>
+std::basic_ostream<charT, traits>&
+operator<<(std::basic_ostream<charT, traits>& os,
+    const basic_string_view<charT, traits>& str)
+{
+    return boost::ostream_string(os, str.data(), str.size());
+}
+```
+
+[endsect]
+
+[section Reference]
+
+```
+namespace boost {
+
+template<class charT, class traits>
+std::basic_ostream<charT, traits>&
+ostream_string(std::basic_ostream<charT, traits>& os,
+    const charT* data, std::size_t size);
+
+} /* boost */
+```
+
+[variablelist
+[[Effects]
+[Behaves like a formatted inserter (as described in
+\[ostream.formatted.reqmts\]) of `os`. Creates a character sequence `seq` of
+`size` characters starting at `data`, each widened using `os.widen()`
+(\[basic.ios.members\]). Determines padding for `seq` as described in
+\[ostream.formatted.reqmts\]. Inserts `seq` into `os`. Calls `width(0)`.]]
+[[Returns] [`os`.]]]
+
+[endsect]

include/boost/utility/ostream_string.hpp

@@ -0,0 +1,95 @@
+/*
+Copyright 2019 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#ifndef BOOST_UTILITY_OSTREAM_STRING_HPP
+#define BOOST_UTILITY_OSTREAM_STRING_HPP
+
+#include <boost/config.hpp>
+#include <iosfwd>
+#include <cstddef>
+
+namespace boost {
+namespace detail {
+
+template<class charT, class traits>
+inline std::size_t
+oss_put(std::basic_ostream<charT, traits>& os, const charT* data,
+    std::size_t size)
+{
+    return static_cast<std::size_t>(os.rdbuf()->sputn(data, size));
+}
+
+template<class charT, class traits>
+inline bool
+oss_fill(std::basic_ostream<charT, traits>& os, std::size_t size)
+{
+    charT c = os.fill();
+    charT fill[] = { c, c, c, c, c, c, c, c };
+    enum {
+        chunk = sizeof fill / sizeof(charT)
+    };
+    for (; size > chunk; size -= chunk) {
+        if (boost::detail::oss_put(os, fill, chunk) != chunk) {
+            return false;
+        }
+    }
+    return boost::detail::oss_put(os, fill, size) == size;
+}
+
+template<class charT, class traits>
+class oss_guard {
+public:
+    explicit oss_guard(std::basic_ostream<charT, traits>& os) BOOST_NOEXCEPT
+        : os_(&os) { }
+    ~oss_guard() BOOST_NOEXCEPT_IF(false) {
+        if (os_) {
+            os_->setstate(std::basic_ostream<charT, traits>::badbit);
+        }
+    }
+    void release() BOOST_NOEXCEPT {
+        os_ = 0;
+    }
+private:
+    oss_guard(const oss_guard&);
+    oss_guard& operator=(const oss_guard&);
+    std::basic_ostream<charT, traits>* os_;
+};
+
+} /* detail */
+
+template<class charT, class traits>
+inline std::basic_ostream<charT, traits>&
+ostream_string(std::basic_ostream<charT, traits>& os, const charT* data,
+    std::size_t size)
+{
+    typedef std::basic_ostream<charT, traits> stream;
+    detail::oss_guard<charT, traits> guard(os);
+    typename stream::sentry entry(os);
+    if (entry) {
+        std::size_t width = static_cast<std::size_t>(os.width());
+        if (width <= size) {
+            if (detail::oss_put(os, data, size) != size) {
+                return os;
+            }
+        } else if ((os.flags() & stream::adjustfield) == stream::left) {
+            if (detail::oss_put(os, data, size) != size ||
+                !detail::oss_fill(os, width - size)) {
+                return os;
+            }
+        } else if (!detail::oss_fill(os, width - size) ||
+            detail::oss_put(os, data, size) != size) {
+            return os;
+        }
+        os.width(0);
+    }
+    guard.release();
+    return os;
+}
+
+} /* boost */
+
+#endif

include/boost/utility/string_ref.hpp

@@ -1,5 +1,6 @@
 /*
    Copyright (c) Marshall Clow 2012-2015.
+   Copyright (c) Glen Joseph Fernandes 2019 (glenjofe@gmail.com)
 
    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)
@@ -17,6 +18,7 @@
 
 #include <boost/config.hpp>
 #include <boost/detail/workaround.hpp>
+#include <boost/utility/ostream_string.hpp>
 #include <boost/utility/string_ref_fwd.hpp>
 #include <boost/throw_exception.hpp>
 
@@ -421,52 +423,11 @@ namespace boost {
         return basic_string_ref<charT, traits>(x) >= y;
         }
 
-    namespace detail {
-
-        template<class charT, class traits>
-        inline void sr_insert_fill_chars(std::basic_ostream<charT, traits>& os, std::size_t n) {
-            enum { chunk_size = 8 };
-            charT fill_chars[chunk_size];
-            std::fill_n(fill_chars, static_cast< std::size_t >(chunk_size), os.fill());
-            for (; n >= chunk_size && os.good(); n -= chunk_size)
-                os.write(fill_chars, static_cast< std::size_t >(chunk_size));
-            if (n > 0 && os.good())
-                os.write(fill_chars, n);
-            }
-
-        template<class charT, class traits>
-        void sr_insert_aligned(std::basic_ostream<charT, traits>& os, const basic_string_ref<charT,traits>& str) {
-            const std::size_t size = str.size();
-            const std::size_t alignment_size = static_cast< std::size_t >(os.width()) - size;
-            const bool align_left = (os.flags() & std::basic_ostream<charT, traits>::adjustfield) == std::basic_ostream<charT, traits>::left;
-            if (!align_left) {
-                detail::sr_insert_fill_chars(os, alignment_size);
-                if (os.good())
-                    os.write(str.data(), size);
-                }
-            else {
-                os.write(str.data(), size);
-                if (os.good())
-                    detail::sr_insert_fill_chars(os, alignment_size);
-                }
-            }
-
-        } // namespace detail
-
     // Inserter
     template<class charT, class traits>
     inline std::basic_ostream<charT, traits>&
     operator<<(std::basic_ostream<charT, traits>& os, const basic_string_ref<charT,traits>& str) {
-        if (os.good()) {
-            const std::size_t size = str.size();
-            const std::size_t w = static_cast< std::size_t >(os.width());
-            if (w <= size)
-                os.write(str.data(), size);
-            else
-                detail::sr_insert_aligned(os, str);
-            os.width(0);
-            }
-        return os;
+        return boost::ostream_string(os, str.data(), str.size());
         }
 
 #if 0

include/boost/utility/string_view.hpp

@@ -1,6 +1,7 @@
 /*
    Copyright (c) Marshall Clow 2012-2015.
    Copyright (c) Beman Dawes 2015
+   Copyright (c) Glen Joseph Fernandes 2019 (glenjofe@gmail.com)
 
    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)
@@ -19,6 +20,7 @@
 
 #include <boost/config.hpp>
 #include <boost/detail/workaround.hpp>
+#include <boost/utility/ostream_string.hpp>
 #include <boost/utility/string_view_fwd.hpp>
 #include <boost/throw_exception.hpp>
 #include <boost/container_hash/hash_fwd.hpp>
@@ -571,53 +573,12 @@ namespace boost {
         return basic_string_view<charT, traits>(x) >= y;
         }
 
-    namespace detail {
-
-        template<class charT, class traits>
-        inline void sv_insert_fill_chars(std::basic_ostream<charT, traits>& os, std::size_t n) {
-            enum { chunk_size = 8 };
-            charT fill_chars[chunk_size];
-            std::fill_n(fill_chars, static_cast< std::size_t >(chunk_size), os.fill());
-            for (; n >= chunk_size && os.good(); n -= chunk_size)
-                os.write(fill_chars, static_cast< std::size_t >(chunk_size));
-            if (n > 0 && os.good())
-                os.write(fill_chars, n);
-            }
-
-        template<class charT, class traits>
-        void sv_insert_aligned(std::basic_ostream<charT, traits>& os, const basic_string_view<charT,traits>& str) {
-            const std::size_t size = str.size();
-            const std::size_t alignment_size = static_cast< std::size_t >(os.width()) - size;
-            const bool align_left = (os.flags() & std::basic_ostream<charT, traits>::adjustfield) == std::basic_ostream<charT, traits>::left;
-            if (!align_left) {
-                detail::sv_insert_fill_chars(os, alignment_size);
-                if (os.good())
-                    os.write(str.data(), size);
-                }
-            else {
-                os.write(str.data(), size);
-                if (os.good())
-                    detail::sv_insert_fill_chars(os, alignment_size);
-                }
-            }
-
-        } // namespace detail
-
     // Inserter
     template<class charT, class traits>
     inline std::basic_ostream<charT, traits>&
     operator<<(std::basic_ostream<charT, traits>& os,
       const basic_string_view<charT,traits>& str) {
-        if (os.good()) {
-            const std::size_t size = str.size();
-            const std::size_t w = static_cast< std::size_t >(os.width());
-            if (w <= size)
-                os.write(str.data(), size);
-            else
-                detail::sv_insert_aligned(os, str);
-            os.width(0);
-            }
-        return os;
+        return boost::ostream_string(os, str.data(), str.size());
         }
 
 #if 0

index.html

@@ -31,6 +31,7 @@
 				<a href="utility.htm#result_of">result_of</a><br>
 				<a href="throw_exception.html">throw_exception</a><br>
 				<a href="utility.htm">utility</a><br>
+            <a href="doc/html/ostream_string.html">ostream_string</a><br>
             <a href="doc/html/string_ref.html">string_ref</a><br>
             <a href="value_init.htm">value_init</a><br>
          </p>

test/Jamfile.v2

@@ -42,3 +42,5 @@ compile-fail value_init_test_fail2.cpp ;
 compile-fail value_init_test_fail3.cpp ;
 compile-fail initialized_test_fail1.cpp ;
 compile-fail initialized_test_fail2.cpp ;
+
+run ostream_string_test.cpp ;

test/ostream_string_test.cpp

@@ -0,0 +1,136 @@
+/*
+Copyright 2019 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#include <boost/core/lightweight_test.hpp>
+#include <boost/utility/ostream_string.hpp>
+#include <sstream>
+#include <string>
+
+int main()
+{
+    {
+        std::ostringstream os;
+        os.width(1);
+        os.fill('.');
+        os.setf(std::ios_base::left, std::ios_base::adjustfield);
+        boost::ostream_string(os, "xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == "xy");
+    }
+    {
+        std::wostringstream os;
+        os.width(1);
+        os.fill('.');
+        os.setf(std::ios_base::left, std::ios_base::adjustfield);
+        boost::ostream_string(os, L"xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == L"xy");
+    }
+    {
+        std::ostringstream os;
+        os.width(1);
+        os.fill('.');
+        os.setf(std::ios_base::right, std::ios_base::adjustfield);
+        boost::ostream_string(os, "xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == "xy");
+    }
+    {
+        std::wostringstream os;
+        os.width(1);
+        os.fill('.');
+        os.setf(std::ios_base::right, std::ios_base::adjustfield);
+        boost::ostream_string(os, L"xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == L"xy");
+    }
+    {
+        std::ostringstream os;
+        os.width(4);
+        os.fill('.');
+        os.setf(std::ios_base::left, std::ios_base::adjustfield);
+        boost::ostream_string(os, "xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == "xy..");
+    }
+    {
+        std::wostringstream os;
+        os.width(4);
+        os.fill(L'.');
+        os.setf(std::ios_base::left, std::ios_base::adjustfield);
+        boost::ostream_string(os, L"xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == L"xy..");
+    }
+    {
+        std::ostringstream os;
+        os.width(4);
+        os.fill('.');
+        os.setf(std::ios_base::right, std::ios_base::adjustfield);
+        boost::ostream_string(os, "xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == "..xy");
+    }
+    {
+        std::wostringstream os;
+        os.width(4);
+        os.fill(L'.');
+        os.setf(std::ios_base::right, std::ios_base::adjustfield);
+        boost::ostream_string(os, L"xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == L"..xy");
+    }
+    {
+        std::ostringstream os;
+        os.width(12);
+        os.fill('.');
+        os.setf(std::ios_base::left, std::ios_base::adjustfield);
+        boost::ostream_string(os, "xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == "xy..........");
+    }
+    {
+        std::wostringstream os;
+        os.width(12);
+        os.fill(L'.');
+        os.setf(std::ios_base::left, std::ios_base::adjustfield);
+        boost::ostream_string(os, L"xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == L"xy..........");
+    }
+    {
+        std::ostringstream os;
+        os.width(12);
+        os.fill('.');
+        os.setf(std::ios_base::right, std::ios_base::adjustfield);
+        boost::ostream_string(os, "xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == "..........xy");
+    }
+    {
+        std::wostringstream os;
+        os.width(12);
+        os.fill(L'.');
+        os.setf(std::ios_base::right, std::ios_base::adjustfield);
+        boost::ostream_string(os, L"xy", 2);
+        BOOST_TEST(os.good());
+        BOOST_TEST(os.width() == 0);
+        BOOST_TEST(os.str() == L"..........xy");
+    }
+    return boost::report_errors();
+}