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Custom FormatSpec (#439) (#444)
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* A custom FormatSpec type can be passed as a template argument to the ArgFormatter chain (#439)

* Corrected nested-name-specifier error

* Spec template argument defaulted to FormatSpec

* Forward declaration of FormatSpec

* Style

* Style (part 2)

* Style (part 3)
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@polyvertex @vitaut
polyvertex authored and vitaut committed Dec 30, 2016
1 parent b9aaa50 commit 554946a
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Showing 5 changed files with 47 additions and 38 deletions.
2 changes: 1 addition & 1 deletion doc/api.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -120,7 +120,7 @@ custom argument formatter class::
// A custom argument formatter that formats negative integers as unsigned
// with the ``x`` format specifier.
class CustomArgFormatter :
public fmt::BasicArgFormatter<CustomArgFormatter, char> {
public fmt::BasicArgFormatter<CustomArgFormatter, char> {
public:
CustomArgFormatter(fmt::BasicFormatter<char, CustomArgFormatter> &f,
fmt::FormatSpec &s, const char *fmt)
Expand Down
57 changes: 33 additions & 24 deletions fmt/format.h
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Original file line number Diff line number Diff line change
Expand Up @@ -431,7 +431,9 @@ typedef BasicWriter<wchar_t> WWriter;
template <typename Char>
class ArgFormatter;

template <typename Impl, typename Char>
struct FormatSpec;

template <typename Impl, typename Char, typename Spec = fmt::FormatSpec>
class BasicPrintfArgFormatter;

template <typename CharType,
Expand Down Expand Up @@ -1697,6 +1699,7 @@ struct TypeSpec : EmptySpec {
int precision() const { return -1; }
bool flag(unsigned) const { return false; }
char type() const { return TYPE; }
char type_prefix() const { return TYPE; }
char fill() const { return ' '; }
};

Expand Down Expand Up @@ -1732,6 +1735,7 @@ struct AlignTypeSpec : AlignSpec {

bool flag(unsigned) const { return false; }
char type() const { return TYPE; }
char type_prefix() const { return TYPE; }
};

// A full format specifier.
Expand All @@ -1747,6 +1751,7 @@ struct FormatSpec : AlignSpec {
bool flag(unsigned f) const { return (flags_ & f) != 0; }
int precision() const { return precision_; }
char type() const { return type_; }
char type_prefix() const { return type_; }
};

// An integer format specifier.
Expand Down Expand Up @@ -1922,11 +1927,11 @@ class ArgMap {
}
};

template <typename Impl, typename Char>
template <typename Impl, typename Char, typename Spec = fmt::FormatSpec>
class ArgFormatterBase : public ArgVisitor<Impl, void> {
private:
BasicWriter<Char> &writer_;
FormatSpec &spec_;
Spec &spec_;

FMT_DISALLOW_COPY_AND_ASSIGN(ArgFormatterBase);

Expand All @@ -1938,7 +1943,7 @@ class ArgFormatterBase : public ArgVisitor<Impl, void> {

protected:
BasicWriter<Char> &writer() { return writer_; }
FormatSpec &spec() { return spec_; }
Spec &spec() { return spec_; }

void write(bool value) {
const char *str_value = value ? "true" : "false";
Expand All @@ -1952,7 +1957,9 @@ class ArgFormatterBase : public ArgVisitor<Impl, void> {
}

public:
ArgFormatterBase(BasicWriter<Char> &w, FormatSpec &s)
typedef Spec SpecType;

ArgFormatterBase(BasicWriter<Char> &w, Spec &s)
: writer_(w), spec_(s) {}

template <typename T>
Expand Down Expand Up @@ -2086,8 +2093,8 @@ class FormatterBase {
will be called.
\endrst
*/
template <typename Impl, typename Char>
class BasicArgFormatter : public internal::ArgFormatterBase<Impl, Char> {
template <typename Impl, typename Char, typename Spec = fmt::FormatSpec>
class BasicArgFormatter : public internal::ArgFormatterBase<Impl, Char, Spec> {
private:
BasicFormatter<Char, Impl> &formatter_;
const Char *format_;
Expand All @@ -2102,8 +2109,8 @@ class BasicArgFormatter : public internal::ArgFormatterBase<Impl, Char> {
\endrst
*/
BasicArgFormatter(BasicFormatter<Char, Impl> &formatter,
FormatSpec &spec, const Char *fmt)
: internal::ArgFormatterBase<Impl, Char>(formatter.writer(), spec),
Spec &spec, const Char *fmt)
: internal::ArgFormatterBase<Impl, Char, Spec>(formatter.writer(), spec),
formatter_(formatter), format_(fmt) {}

/** Formats an argument of a custom (user-defined) type. */
Expand All @@ -2114,12 +2121,14 @@ class BasicArgFormatter : public internal::ArgFormatterBase<Impl, Char> {

/** The default argument formatter. */
template <typename Char>
class ArgFormatter : public BasicArgFormatter<ArgFormatter<Char>, Char> {
class ArgFormatter :
public BasicArgFormatter<ArgFormatter<Char>, Char, FormatSpec> {
public:
/** Constructs an argument formatter object. */
ArgFormatter(BasicFormatter<Char> &formatter,
FormatSpec &spec, const Char *fmt)
: BasicArgFormatter<ArgFormatter<Char>, Char>(formatter, spec, fmt) {}
: BasicArgFormatter<ArgFormatter<Char>,
Char, FormatSpec>(formatter, spec, fmt) {}
};

/** This template formats data and writes the output to a writer. */
Expand Down Expand Up @@ -2501,16 +2510,16 @@ class BasicWriter {
void write_int(T value, Spec spec);

// Formats a floating-point number (double or long double).
template <typename T>
void write_double(T value, const FormatSpec &spec);
template <typename T, typename Spec>
void write_double(T value, const Spec &spec);

// Writes a formatted string.
template <typename StrChar>
CharPtr write_str(const StrChar *s, std::size_t size, const AlignSpec &spec);

template <typename StrChar>
template <typename StrChar, typename Spec>
void write_str(const internal::Arg::StringValue<StrChar> &str,
const FormatSpec &spec);
const Spec &spec);

// This following methods are private to disallow writing wide characters
// and strings to a char stream. If you want to print a wide string as a
Expand All @@ -2529,10 +2538,10 @@ class BasicWriter {
template<typename T>
void append_float_length(Char *&, T) {}

template <typename Impl, typename Char_>
template <typename Impl, typename Char_, typename Spec_>
friend class internal::ArgFormatterBase;

template <typename Impl, typename Char_>
template <typename Impl, typename Char_, typename Spec_>
friend class BasicPrintfArgFormatter;

protected:
Expand Down Expand Up @@ -2729,9 +2738,9 @@ typename BasicWriter<Char>::CharPtr BasicWriter<Char>::write_str(
}

template <typename Char>
template <typename StrChar>
template <typename StrChar, typename Spec>
void BasicWriter<Char>::write_str(
const internal::Arg::StringValue<StrChar> &s, const FormatSpec &spec) {
const internal::Arg::StringValue<StrChar> &s, const Spec &spec) {
// Check if StrChar is convertible to Char.
internal::CharTraits<Char>::convert(StrChar());
if (spec.type_ && spec.type_ != 's')
Expand Down Expand Up @@ -2855,7 +2864,7 @@ void BasicWriter<Char>::write_int(T value, Spec spec) {
UnsignedType n = abs_value;
if (spec.flag(HASH_FLAG)) {
prefix[prefix_size++] = '0';
prefix[prefix_size++] = spec.type();
prefix[prefix_size++] = spec.type_prefix();
}
unsigned num_digits = 0;
do {
Expand All @@ -2875,7 +2884,7 @@ void BasicWriter<Char>::write_int(T value, Spec spec) {
UnsignedType n = abs_value;
if (spec.flag(HASH_FLAG)) {
prefix[prefix_size++] = '0';
prefix[prefix_size++] = spec.type();
prefix[prefix_size++] = spec.type_prefix();
}
unsigned num_digits = 0;
do {
Expand Down Expand Up @@ -2923,8 +2932,8 @@ void BasicWriter<Char>::write_int(T value, Spec spec) {
}

template <typename Char>
template <typename T>
void BasicWriter<Char>::write_double(T value, const FormatSpec &spec) {
template <typename T, typename Spec>
void BasicWriter<Char>::write_double(T value, const Spec &spec) {
// Check type.
char type = spec.type();
bool upper = false;
Expand Down Expand Up @@ -3661,7 +3670,7 @@ const Char *BasicFormatter<Char, ArgFormatter>::format(
const Char *&format_str, const internal::Arg &arg) {
using internal::Arg;
const Char *s = format_str;
FormatSpec spec;
typename ArgFormatter::SpecType spec;
if (*s == ':') {
if (arg.type == Arg::CUSTOM) {
arg.custom.format(this, arg.custom.value, &s);
Expand Down
21 changes: 11 additions & 10 deletions fmt/printf.h
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Original file line number Diff line number Diff line change
Expand Up @@ -189,15 +189,16 @@ class WidthHandler : public ArgVisitor<WidthHandler, unsigned> {
superclass will be called.
\endrst
*/
template <typename Impl, typename Char>
class BasicPrintfArgFormatter : public internal::ArgFormatterBase<Impl, Char> {
template <typename Impl, typename Char, typename Spec>
class BasicPrintfArgFormatter :
public internal::ArgFormatterBase<Impl, Char, Spec> {
private:
void write_null_pointer() {
this->spec().type_ = 0;
this->write("(nil)");
}

typedef internal::ArgFormatterBase<Impl, Char> Base;
typedef internal::ArgFormatterBase<Impl, Char, Spec> Base;

public:
/**
Expand All @@ -207,12 +208,12 @@ class BasicPrintfArgFormatter : public internal::ArgFormatterBase<Impl, Char> {
specifier information for standard argument types.
\endrst
*/
BasicPrintfArgFormatter(BasicWriter<Char> &w, FormatSpec &s)
: internal::ArgFormatterBase<Impl, Char>(w, s) {}
BasicPrintfArgFormatter(BasicWriter<Char> &w, Spec &s)
: internal::ArgFormatterBase<Impl, Char, Spec>(w, s) {}

/** Formats an argument of type ``bool``. */
void visit_bool(bool value) {
FormatSpec &fmt_spec = this->spec();
Spec &fmt_spec = this->spec();
if (fmt_spec.type_ != 's')
return this->visit_any_int(value);
fmt_spec.type_ = 0;
Expand All @@ -221,7 +222,7 @@ class BasicPrintfArgFormatter : public internal::ArgFormatterBase<Impl, Char> {

/** Formats a character. */
void visit_char(int value) {
const FormatSpec &fmt_spec = this->spec();
const Spec &fmt_spec = this->spec();
BasicWriter<Char> &w = this->writer();
if (fmt_spec.type_ && fmt_spec.type_ != 'c')
w.write_int(value, fmt_spec);
Expand Down Expand Up @@ -271,12 +272,12 @@ class BasicPrintfArgFormatter : public internal::ArgFormatterBase<Impl, Char> {

/** The default printf argument formatter. */
template <typename Char>
class PrintfArgFormatter
: public BasicPrintfArgFormatter<PrintfArgFormatter<Char>, Char> {
class PrintfArgFormatter :
public BasicPrintfArgFormatter<PrintfArgFormatter<Char>, Char, FormatSpec> {
public:
/** Constructs an argument formatter object. */
PrintfArgFormatter(BasicWriter<Char> &w, FormatSpec &s)
: BasicPrintfArgFormatter<PrintfArgFormatter<Char>, Char>(w, s) {}
: BasicPrintfArgFormatter<PrintfArgFormatter<Char>, Char, FormatSpec>(w, s) {}
};

/** This template formats data and writes the output to a writer. */
Expand Down
4 changes: 2 additions & 2 deletions test/custom-formatter-test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -30,8 +30,8 @@ class CustomArgFormatter

// A custom argument formatter that doesn't print `-` for floating-point values
// rounded to 0.
class CustomPrintfArgFormatter :
public BasicPrintfArgFormatter<CustomPrintfArgFormatter, char> {
class CustomPrintfArgFormatter
: public BasicPrintfArgFormatter<CustomPrintfArgFormatter, char> {
public:
typedef BasicPrintfArgFormatter<CustomPrintfArgFormatter, char> Base;

Expand Down
1 change: 0 additions & 1 deletion test/format-test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1660,4 +1660,3 @@ void convert(int);
TEST(FormatTest, ConvertCollision) {
fmt::format("{}", 42);
}

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