1 /*
2 Copyright 2019 Glen Joseph Fernandes
3 (glenjofe@gmail.com)
4
5 Distributed under the Boost Software License, Version 1.0.
6 (http://www.boost.org/LICENSE_1_0.txt)
7 */
8 #ifndef BOOST_UTILITY_OSTREAM_STRING_HPP
9 #define BOOST_UTILITY_OSTREAM_STRING_HPP
10
11 #include <boost/config.hpp>
12 #include <iosfwd>
13 #include <cstddef>
14
15 namespace boost {
16 namespace detail {
17
18 template<class charT, class traits>
19 inline std::size_t
oss_put(std::basic_ostream<charT,traits> & os,const charT * data,std::size_t size)20 oss_put(std::basic_ostream<charT, traits>& os, const charT* data,
21 std::size_t size)
22 {
23 return static_cast<std::size_t>(os.rdbuf()->sputn(data, size));
24 }
25
26 template<class charT, class traits>
27 inline bool
oss_fill(std::basic_ostream<charT,traits> & os,std::size_t size)28 oss_fill(std::basic_ostream<charT, traits>& os, std::size_t size)
29 {
30 charT c = os.fill();
31 charT fill[] = { c, c, c, c, c, c, c, c };
32 enum {
33 chunk = sizeof fill / sizeof(charT)
34 };
35 for (; size > chunk; size -= chunk) {
36 if (boost::detail::oss_put(os, fill, chunk) != chunk) {
37 return false;
38 }
39 }
40 return boost::detail::oss_put(os, fill, size) == size;
41 }
42
43 template<class charT, class traits>
44 class oss_guard {
45 public:
oss_guard(std::basic_ostream<charT,traits> & os)46 explicit oss_guard(std::basic_ostream<charT, traits>& os) BOOST_NOEXCEPT
47 : os_(&os) { }
BOOST_NOEXCEPT_IF(false)48 ~oss_guard() BOOST_NOEXCEPT_IF(false) {
49 if (os_) {
50 os_->setstate(std::basic_ostream<charT, traits>::badbit);
51 }
52 }
release()53 void release() BOOST_NOEXCEPT {
54 os_ = 0;
55 }
56 private:
57 oss_guard(const oss_guard&);
58 oss_guard& operator=(const oss_guard&);
59 std::basic_ostream<charT, traits>* os_;
60 };
61
62 } /* detail */
63
64 template<class charT, class traits>
65 inline std::basic_ostream<charT, traits>&
ostream_string(std::basic_ostream<charT,traits> & os,const charT * data,std::size_t size)66 ostream_string(std::basic_ostream<charT, traits>& os, const charT* data,
67 std::size_t size)
68 {
69 typedef std::basic_ostream<charT, traits> stream;
70 detail::oss_guard<charT, traits> guard(os);
71 typename stream::sentry entry(os);
72 if (entry) {
73 std::size_t width = static_cast<std::size_t>(os.width());
74 if (width <= size) {
75 if (detail::oss_put(os, data, size) != size) {
76 return os;
77 }
78 } else if ((os.flags() & stream::adjustfield) == stream::left) {
79 if (detail::oss_put(os, data, size) != size ||
80 !detail::oss_fill(os, width - size)) {
81 return os;
82 }
83 } else if (!detail::oss_fill(os, width - size) ||
84 detail::oss_put(os, data, size) != size) {
85 return os;
86 }
87 os.width(0);
88 }
89 guard.release();
90 return os;
91 }
92
93 } /* boost */
94
95 #endif
96