Implemented #335: custom printf support

test/CMakeLists.txt

@@ -80,6 +80,7 @@ add_fmt_test(printf-test)
 add_fmt_test(string-test)
 add_fmt_test(util-test mock-allocator.h)
 add_fmt_test(macro-test)
+add_fmt_test(custom-formatter-test)
 
 # Enable stricter options for one test to make sure that the header is free of
 # warnings.

test/custom-formatter-test.cc

@@ -0,0 +1,65 @@
+/*
+ Custom argument formatter tests
+
+ Copyright (c) 2016, Victor Zverovich
+ All rights reserved.
+
+ For the license information refer to format.h.
+ */
+
+#include "fmt/printf.h"
+#include "gtest-extra.h"
+
+using fmt::internal::BasicPrintfArgFormatter;
+
+// A custom argument formatter that doesn't print `-` for floating-point values
+// rounded to 0.
+class CustomArgFormatter
+  : public fmt::BasicArgFormatter<CustomArgFormatter, char> {
+ public:
+  CustomArgFormatter(fmt::BasicFormatter<char, CustomArgFormatter> &f,
+                     fmt::FormatSpec &s, const char *fmt)
+  : fmt::BasicArgFormatter<CustomArgFormatter, char>(f, s, fmt) {}
+
+  void visit_double(double value) {
+    if (round(value * pow(10, spec().precision())) == 0)
+      value = 0;
+    fmt::BasicArgFormatter<CustomArgFormatter, char>::visit_double(value);
+  }
+};
+
+// A custom argument formatter that doesn't print `-` for floating-point values
+// rounded to 0.
+class CustomPAF : public BasicPrintfArgFormatter<CustomPAF, char> {
+ public:
+  CustomPAF(fmt::BasicWriter<char> &writer, fmt::FormatSpec &spec)
+  : BasicPrintfArgFormatter<CustomPAF, char>(writer, spec) {}
+
+  void visit_double(double value) {
+    if (round(value * pow(10, spec().precision())) == 0)
+      value = 0;
+    BasicPrintfArgFormatter<CustomPAF, char>::visit_double(value);
+  }
+};
+
+std::string custom_format(const char *format_str, fmt::ArgList args) {
+  fmt::MemoryWriter writer;
+  // Pass custom argument formatter as a template arg to BasicFormatter.
+  fmt::BasicFormatter<char, CustomArgFormatter> formatter(args, writer);
+  formatter.format(format_str);
+  return writer.str();
+}
+FMT_VARIADIC(std::string, custom_format, const char *)
+
+std::string custom_sprintf(const char* fstr, fmt::ArgList args){
+  fmt::MemoryWriter writer;
+  fmt::internal::PrintfFormatter< char, CustomPAF > pfer( args);
+  pfer.format(writer, fstr);
+  return writer.str();
+}
+FMT_VARIADIC(std::string, custom_sprintf, const char*);
+
+TEST(CustomFormatterTest, Format) {
+  EXPECT_EQ("0.00", custom_format("{:.2f}", -.00001));
+  EXPECT_EQ("0.00", custom_sprintf("%.2f", -.00001));
+}

test/format-impl-test.cc

@@ -46,7 +46,7 @@ TEST(FormatTest, ArgConverter) {
   Arg arg = Arg();
   arg.type = Arg::LONG_LONG;
   arg.long_long_value = std::numeric_limits<fmt::LongLong>::max();
-  fmt::ArgConverter<fmt::LongLong>(arg, 'd').visit(arg);
+  fmt::internal::ArgConverter<fmt::LongLong>(arg, 'd').visit(arg);
   EXPECT_EQ(Arg::LONG_LONG, arg.type);
 }
 

test/printf-test.cc

@@ -29,6 +29,7 @@
 #include <climits>
 #include <cstring>
 
+#include "fmt/printf.h"
 #include "fmt/format.h"
 #include "gtest-extra.h"
 #include "util.h"