Make buffer_range public and update custom formatting docs (#1281)

doc/api.rst

@@ -278,21 +278,21 @@ Custom Formatting of Built-in Types
 It is possible to change the way arguments are formatted by providing a
 custom argument formatter class::
 
-  using arg_formatter =
-    fmt::arg_formatter<fmt::back_insert_range<fmt::internal::buffer>>;
+  using arg_formatter = fmt::arg_formatter<fmt::buffer_range<char>>;
 
   // A custom argument formatter that formats negative integers as unsigned
   // with the ``x`` format specifier.
   class custom_arg_formatter : public arg_formatter {
    public:
-    custom_arg_formatter(fmt::format_context &ctx,
-                         fmt::format_specs *spec = nullptr)
-      : arg_formatter(ctx, spec) {}
+    custom_arg_formatter(fmt::format_context& ctx,
+                         fmt::format_parse_context* parse_ctx = nullptr,
+                         fmt::format_specs* spec = nullptr)
+      : arg_formatter(ctx, parse_ctx, spec) {}
 
     using arg_formatter::operator();
 
     auto operator()(int value) {
-      if (spec().type() == 'x')
+      if (specs() && specs()->type == 'x')
         return (*this)(static_cast<unsigned>(value)); // convert to unsigned and format
       return arg_formatter::operator()(value);
     }

include/fmt/compile.h

@@ -426,7 +426,7 @@ template <typename CompiledFormat, typename... Args,
           typename Char = typename CompiledFormat::char_type>
 std::basic_string<Char> format(const CompiledFormat& cf, const Args&... args) {
   basic_memory_buffer<Char> buffer;
-  using range = internal::buffer_range<Char>;
+  using range = buffer_range<Char>;
   using context = buffer_context<Char>;
   cf.template vformat_to<range, context>(range(buffer),
                                          {make_format_args<context>(args...)});

include/fmt/format.h

@@ -413,17 +413,6 @@ class output_range {
   sentinel end() const { return {}; }  // Sentinel is not used yet.
 };
 
-// A range with an iterator appending to a buffer.
-template <typename T>
-class buffer_range
-    : public output_range<std::back_insert_iterator<buffer<T>>, T> {
- public:
-  using iterator = std::back_insert_iterator<buffer<T>>;
-  using output_range<iterator, T>::output_range;
-  buffer_range(buffer<T>& buf)
-      : output_range<iterator, T>(std::back_inserter(buf)) {}
-};
-
 template <typename Char>
 inline size_t count_code_points(basic_string_view<Char> s) {
   return s.size();
@@ -478,6 +467,17 @@ void buffer<T>::append(const U* begin, const U* end) {
 }
 }  // namespace internal
 
+// A range with an iterator appending to a buffer.
+template <typename T>
+class buffer_range : public internal::output_range<
+                         std::back_insert_iterator<internal::buffer<T>>, T> {
+ public:
+  using iterator = std::back_insert_iterator<internal::buffer<T>>;
+  using internal::output_range<iterator, T>::output_range;
+  buffer_range(internal::buffer<T>& buf)
+      : internal::output_range<iterator, T>(std::back_inserter(buf)) {}
+};
+
 // A UTF-8 string view.
 class u8string_view : public basic_string_view<char8_t> {
  public:
@@ -2598,7 +2598,7 @@ template <typename Range>
 using basic_writer FMT_DEPRECATED_ALIAS = internal::basic_writer<Range>;
 using writer FMT_DEPRECATED_ALIAS = internal::writer;
 using wwriter FMT_DEPRECATED_ALIAS =
-    internal::basic_writer<internal::buffer_range<wchar_t>>;
+    internal::basic_writer<buffer_range<wchar_t>>;
 
 /** The default argument formatter. */
 template <typename Range>

include/fmt/printf.h

@@ -368,8 +368,7 @@ template <typename OutputIt, typename Char> class basic_printf_context {
   }
 
   /** Formats stored arguments and writes the output to the range. */
-  template <typename ArgFormatter =
-                printf_arg_formatter<internal::buffer_range<Char>>>
+  template <typename ArgFormatter = printf_arg_formatter<buffer_range<Char>>>
   OutputIt format();
 };
 

test/custom-formatter-test.cc

@@ -18,9 +18,9 @@
 // A custom argument formatter that doesn't print `-` for floating-point values
 // rounded to 0.
 class custom_arg_formatter
-    : public fmt::arg_formatter<fmt::internal::buffer_range<char>> {
+    : public fmt::arg_formatter<fmt::buffer_range<char>> {
  public:
-  using range = fmt::internal::buffer_range<char>;
+  using range = fmt::buffer_range<char>;
   typedef fmt::arg_formatter<range> base;
 
   custom_arg_formatter(fmt::format_context& ctx,

test/format

@@ -718,7 +718,7 @@ template<class... Args>
 string vformat(string_view fmt, format_args args) {
   fmt::memory_buffer mbuf;
   fmt::internal::buffer<char>& buf = mbuf;
-  using range = fmt::internal::buffer_range<char>;
+  using range = fmt::buffer_range<char>;
   detail::format_handler<detail::arg_formatter<range>, char, format_context>
     h(range(std::back_inserter(buf)), fmt, args, {});
   fmt::internal::parse_format_string<false>(fmt::to_string_view(fmt), h);

test/format-test.cc

@@ -99,7 +99,7 @@ void std_format(long double value, std::wstring& result) {
 template <typename Char, typename T>
 ::testing::AssertionResult check_write(const T& value, const char* type) {
   fmt::basic_memory_buffer<Char> buffer;
-  using range = fmt::internal::buffer_range<Char>;
+  using range = fmt::buffer_range<Char>;
   basic_writer<range> writer(buffer);
   writer.write(value);
   std::basic_string<Char> actual = to_string(buffer);
@@ -1911,7 +1911,7 @@ enum TestFixedEnum : short { B };
 TEST(FormatTest, FixedEnum) { EXPECT_EQ("0", fmt::format("{}", B)); }
 #endif
 
-using buffer_range = fmt::internal::buffer_range<char>;
+using buffer_range = fmt::buffer_range<char>;
 
 class mock_arg_formatter
     : public fmt::internal::arg_formatter_base<buffer_range> {

test/ostream-test.cc

@@ -64,7 +64,7 @@ TEST(OStreamTest, Enum) {
   EXPECT_EQ(L"0", fmt::format(L"{}", unstreamable_enum()));
 }
 
-using range = fmt::internal::buffer_range<char>;
+using range = fmt::buffer_range<char>;
 
 struct test_arg_formatter : fmt::arg_formatter<range> {
   fmt::format_parse_context parse_ctx;

test/printf-test.cc

@@ -561,8 +561,7 @@ TEST(PrintfTest, VSPrintfMakeWArgsExample) {
 #endif
 }
 
-typedef fmt::printf_arg_formatter<fmt::internal::buffer_range<char>>
-    formatter_t;
+typedef fmt::printf_arg_formatter<fmt::buffer_range<char>> formatter_t;
 typedef fmt::basic_printf_context<formatter_t::iterator, char> context_t;
 
 // A custom printf argument formatter that doesn't print `-` for floating-point