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Add support for '%' type to output floating point values as a percentage. #1060

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Add support for '%' type to output floating point values as a percentage. #1060

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29db6bd
Add support for '%' type to output floating point values as a
gawain-bolton Mar 1, 2019
73f31a8
Updates for formatting output as a percentage.
gawain-bolton Mar 3, 2019
d6d33a9
Changes to fix CI as g++-4.4 BUILD was broken.
gawain-bolton Mar 3, 2019
141d1cf
Revert unnecessary changes.
gawain-bolton Mar 4, 2019
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12 changes: 9 additions & 3 deletions include/fmt/format-inl.h
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Original file line number Diff line number Diff line change
Expand Up @@ -539,8 +539,7 @@ struct fixed_stop {
void on_exp(int exp) {
if (!fixed) return;
exp += exp10;
if (exp >= 0)
precision += exp;
if (exp >= 0) precision += exp;
}

bool operator()(char*, int& size, uint64_t remainder, uint64_t divisor,
Expand Down Expand Up @@ -656,7 +655,14 @@ void sprintf_format(Double value, internal::buffer& buf,
*format_ptr++ = '*';
}
if (std::is_same<Double, long double>::value) *format_ptr++ = 'L';
char type = spec.type ? spec.type : 'g';

char type = spec.type;

if (type == '%') {
type = 'f';
} else if (type == 0) {
type = 'g';
}
#if FMT_MSC_VER
if (type == 'F') {
// MSVC's printf doesn't support 'F'.
Expand Down
30 changes: 26 additions & 4 deletions include/fmt/format.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1274,6 +1274,9 @@ FMT_CONSTEXPR void handle_float_type_spec(char spec, Handler&& handler) {
case 'F':
handler.on_fixed();
break;
case '%':
handler.on_percent();
break;
case 'a':
case 'A':
handler.on_hex();
Expand Down Expand Up @@ -1338,6 +1341,7 @@ class float_type_checker : private ErrorHandler {
FMT_CONSTEXPR void on_general() {}
FMT_CONSTEXPR void on_exp() {}
FMT_CONSTEXPR void on_fixed() {}
FMT_CONSTEXPR void on_percent() {}
FMT_CONSTEXPR void on_hex() {}

FMT_CONSTEXPR void on_error() {
Expand Down Expand Up @@ -2642,17 +2646,20 @@ template <typename Range> class basic_writer {

struct inf_or_nan_writer {
char sign;
bool as_percentage;
const char* str;

size_t size() const {
return static_cast<std::size_t>(INF_SIZE + (sign ? 1 : 0));
return static_cast<std::size_t>(INF_SIZE + (sign ? 1 : 0) +
(as_percentage ? 1 : 0));
}
size_t width() const { return size(); }

template <typename It> void operator()(It&& it) const {
if (sign) *it++ = static_cast<char_type>(sign);
it = internal::copy_str<char_type>(
str, str + static_cast<std::size_t>(INF_SIZE), it);
if (as_percentage) *it++ = static_cast<char_type>('%');
}
};

Expand Down Expand Up @@ -2810,8 +2817,9 @@ struct float_spec_handler {
char type;
bool upper;
bool fixed;
bool as_percentage;

explicit float_spec_handler(char t) : type(t), upper(false), fixed(false) {}
explicit float_spec_handler(char t) : type(t), upper(false), fixed(false), as_percentage(false) {}

void on_general() {
if (type == 'G') upper = true;
Expand All @@ -2826,6 +2834,11 @@ struct float_spec_handler {
if (type == 'F') upper = true;
}

void on_percent() {
fixed = true;
as_percentage = true;
}

void on_hex() {
if (type == 'A') upper = true;
}
Expand Down Expand Up @@ -2854,10 +2867,11 @@ void basic_writer<Range>::write_double(T value, const format_specs& spec) {
basic_writer& writer;
format_specs spec;
char sign;
bool as_percentage;
void operator()(const char* str) const {
writer.write_padded(spec, inf_or_nan_writer{sign, str});
writer.write_padded(spec, inf_or_nan_writer{sign, as_percentage, str});
}
} write_inf_or_nan = {*this, spec, sign};
} write_inf_or_nan = {*this, spec, sign, handler.as_percentage};

// Format NaN and ininity ourselves because sprintf's output is not consistent
// across platforms.
Expand All @@ -2869,11 +2883,19 @@ void basic_writer<Range>::write_double(T value, const format_specs& spec) {
memory_buffer buffer;
int exp = 0;
int precision = spec.has_precision() || !spec.type ? spec.precision : 6;

if (handler.as_percentage) value *= 100.;

bool use_grisu = fmt::internal::use_grisu<T>() &&
(!spec.type || handler.fixed) &&
internal::grisu2_format(static_cast<double>(value), buffer,
precision, handler.fixed, exp);
if (!use_grisu) internal::sprintf_format(value, buffer, spec);

if (handler.as_percentage) {
buffer.push_back('%');
--exp; // Adjust decimal place position.
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Shouldn't this be -= 2?

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The decimal place position is shifted by one place because only one character, the percent sign, is added.

}
align_spec as = spec;
if (spec.align() == ALIGN_NUMERIC) {
if (sign) {
Expand Down
11 changes: 10 additions & 1 deletion test/format-test.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -1207,6 +1207,8 @@ TEST(FormatterTest, Precision) {
"precision not allowed for this argument type");
EXPECT_THROW_MSG(format("{0:.2f}", 42ull), format_error,
"precision not allowed for this argument type");
EXPECT_THROW_MSG(format("{0:.2%}", 42), format_error,
"precision not allowed for this argument type");
EXPECT_THROW_MSG(format("{0:3.0}", 'x'), format_error,
"precision not allowed for this argument type");
EXPECT_EQ("1.2", format("{0:.2}", 1.2345));
Expand Down Expand Up @@ -1440,10 +1442,11 @@ TEST(FormatterTest, FormatConvertibleToLongLong) {

TEST(FormatterTest, FormatFloat) {
EXPECT_EQ("392.500000", format("{0:f}", 392.5f));
EXPECT_EQ("12.500000%", format("{0:%}", 0.125f));
}

TEST(FormatterTest, FormatDouble) {
check_unknown_types(1.2, "eEfFgGaA", "double");
check_unknown_types(1.2, "eEfFgGaA%", "double");
EXPECT_EQ("0.0", format("{:}", 0.0));
EXPECT_EQ("0.000000", format("{:f}", 0.0));
EXPECT_EQ("0", format("{:g}", 0.0));
Expand All @@ -1452,6 +1455,8 @@ TEST(FormatterTest, FormatDouble) {
EXPECT_EQ("392.65", format("{:G}", 392.65));
EXPECT_EQ("392.650000", format("{:f}", 392.65));
EXPECT_EQ("392.650000", format("{:F}", 392.65));
EXPECT_EQ("12.500000%", format("{:%}", 0.125));
EXPECT_EQ("12.34%", format("{:.2%}", 0.1234432));
char buffer[BUFFER_SIZE];
safe_sprintf(buffer, "%e", 392.65);
EXPECT_EQ(buffer, format("{0:e}", 392.65));
Expand All @@ -1473,6 +1478,7 @@ TEST(FormatterTest, FormatNaN) {
EXPECT_EQ("nan ", format("{:<7}", nan));
EXPECT_EQ(" nan ", format("{:^7}", nan));
EXPECT_EQ(" nan", format("{:>7}", nan));
EXPECT_EQ("nan%", format("{:%}", nan));
}

TEST(FormatterTest, FormatInfinity) {
Expand All @@ -1485,6 +1491,7 @@ TEST(FormatterTest, FormatInfinity) {
EXPECT_EQ("inf ", format("{:<7}", inf));
EXPECT_EQ(" inf ", format("{:^7}", inf));
EXPECT_EQ(" inf", format("{:>7}", inf));
EXPECT_EQ("inf%", format("{:%}", inf));
}

TEST(FormatterTest, FormatLongDouble) {
Expand All @@ -1495,6 +1502,8 @@ TEST(FormatterTest, FormatLongDouble) {
EXPECT_EQ("392.65", format("{0:G}", 392.65l));
EXPECT_EQ("392.650000", format("{0:f}", 392.65l));
EXPECT_EQ("392.650000", format("{0:F}", 392.65l));
EXPECT_EQ("12.500000%", format("{:%}", 0.125l));
EXPECT_EQ("12.34%", format("{:.2%}", 0.1234432l));
char buffer[BUFFER_SIZE];
safe_sprintf(buffer, "%Le", 392.65l);
EXPECT_EQ(buffer, format("{0:e}", 392.65l));
Expand Down