Support stream width and fill and write directly to stream buffer

include/boost/io/quoted.hpp

@@ -1,7 +1,7 @@
 /*
 Copyright 2010 Beman Dawes
 
-Copyright 2019 Glen Joseph Fernandes
+Copyright 2019-2020 Glen Joseph Fernandes
 (glenjofe@gmail.com)
 
 Distributed under the Boost Software License, Version 1.0.
@@ -10,10 +10,9 @@ Distributed under the Boost Software License, Version 1.0.
 #ifndef BOOST_IO_QUOTED_HPP
 #define BOOST_IO_QUOTED_HPP
 
+#include <boost/io/detail/buffer_fill.hpp>
+#include <boost/io/detail/ostream_guard.hpp>
 #include <boost/io/ios_state.hpp>
-#include <ios>
-#include <iterator>
-#include <string>
 
 namespace boost {
 namespace io {
@@ -26,37 +25,113 @@ struct quoted_proxy {
     Char delim;
 };
 
+template<class Char>
+struct quoted_state {
+    const Char* string;
+    std::size_t size;
+    std::size_t count;
+};
+
+template<class Char>
+inline quoted_state<Char>
+quoted_start(const Char* string, Char escape, Char delim)
+{
+    const Char* end = string;
+    std::size_t count = 2;
+    for (Char ch; (ch = *end) != 0; ++end) {
+        count += 1 + (ch == escape || ch == delim);
+    }
+    quoted_state<Char> state = { string,
+        static_cast<std::size_t>(end - string), count };
+    return state;
+}
+
+template<class Char, class String>
+inline quoted_state<Char>
+quoted_start(const String* string, Char escape, Char delim)
+{
+    const Char* begin = string->data();
+    std::size_t size = string->size();
+    std::size_t count = 2;
+    for (const Char *it = begin, *end = begin + size; it != end; ++it) {
+        Char ch = *it;
+        count += 1 + (ch == escape || ch == delim);
+    }
+    quoted_state<Char> state = { begin, size, count };
+    return state;
+}
+
+template<class Char, class Traits>
+inline bool
+quoted_put(std::basic_streambuf<Char, Traits>& buf, const Char* string,
+    std::size_t size, std::size_t count, Char escape, Char delim)
+{
+    if (buf.sputc(delim) == Traits::eof()) {
+        return false;
+    }
+    if (size == count) {
+        if (static_cast<std::size_t>(buf.sputn(string, size)) != size) {
+            return false;
+        }
+    } else {
+        for (const Char* end = string + size; string != end; ++string) {
+            Char ch = *string;
+            if ((ch == escape || ch == delim) &&
+                buf.sputc(escape) == Traits::eof()) {
+                return false;
+            }
+            if (buf.sputc(ch) == Traits::eof()) {
+                return false;
+            }
+        }
+    }
+    return buf.sputc(delim) != Traits::eof();
+}
+
+template<class Char, class Traits, class String>
+inline std::basic_ostream<Char, Traits>&
+quoted_out(std::basic_ostream<Char, Traits>& os, String* string, Char escape,
+    Char delim)
+{
+    typedef std::basic_ostream<Char, Traits> stream;
+    ostream_guard<Char, Traits> guard(os);
+    typename stream::sentry entry(os);
+    if (entry) {
+        quoted_state<Char> state = boost::io::detail::quoted_start(string,
+            escape, delim);
+        std::basic_streambuf<Char, Traits>& buf = *os.rdbuf();
+        std::size_t width = static_cast<std::size_t>(os.width());
+        if (width <= state.count) {
+            if (!boost::io::detail::quoted_put(buf, state.string, state.size,
+                state.count, escape, delim)) {
+                return os;
+            }
+        } else if ((os.flags() & stream::adjustfield) == stream::left) {
+            if (!boost::io::detail::quoted_put(buf, state.string, state.size,
+                    state.count, escape, delim) ||
+                !boost::io::detail::buffer_fill(buf, os.fill(),
+                    width - state.count)) {
+                return os;
+            }
+        } else if (!boost::io::detail::buffer_fill(buf, os.fill(),
+                width - state.count) ||
+            !boost::io::detail::quoted_put(buf, state.string, state.size,
+                state.count, escape, delim)) {
+            return os;
+        }
+        os.width(0);
+    }
+    guard.release();
+    return os;
+}
+
 template<class Char, class Traits>
 inline std::basic_ostream<Char, Traits>&
 operator<<(std::basic_ostream<Char, Traits>& os,
     const quoted_proxy<const Char*, Char>& proxy)
 {
-    os.put(proxy.delim);
-    for (const Char* it = proxy.string; *it; ++it) {
-        if (*it == proxy.delim || *it == proxy.escape) {
-            os.put(proxy.escape);
-        }
-        os.put(*it);
-    }
-    return os.put(proxy.delim);
-}
-
-template<class Char, class Traits, class Alloc>
-inline std::basic_ostream<Char, Traits>&
-quoted_output(std::basic_ostream<Char, Traits>& os,
-    const std::basic_string<Char, Traits, Alloc>& string, Char escape,
-    Char delim)
-{
-    os.put(delim);
-    for (typename std::basic_string<Char, Traits,
-            Alloc>::const_iterator it = string.begin(), end = string.end();
-        it != end; ++it) {
-        if (*it == delim || *it == escape) {
-            os.put(escape);
-        }
-        os.put(*it);
-    }
-    return os.put(delim);
+    return boost::io::detail::quoted_out(os, proxy.string, proxy.escape,
+        proxy.delim);
 }
 
 template <class Char, class Traits, class Alloc>
@@ -65,7 +140,7 @@ operator<<(std::basic_ostream<Char, Traits>& os,
     const quoted_proxy<const std::basic_string<Char, Traits, Alloc>*,
         Char>& proxy)
 {
-    return boost::io::detail::quoted_output(os, *proxy.string, proxy.escape,
+    return boost::io::detail::quoted_out(os, proxy.string, proxy.escape,
         proxy.delim);
 }
 
@@ -74,7 +149,7 @@ inline std::basic_ostream<Char, Traits>&
 operator<<(std::basic_ostream<Char, Traits>& os,
     const quoted_proxy<std::basic_string<Char, Traits, Alloc>*, Char>& proxy)
 {
-    return boost::io::detail::quoted_output(os, *proxy.string, proxy.escape,
+    return boost::io::detail::quoted_out(os, proxy.string, proxy.escape,
         proxy.delim);
 }