Rewrote format_impl.h functions to work with both decimal and binary

const_fmt/format.h

@@ -42,12 +42,12 @@ constexpr inline void check_fmt_params() {
 
 template <fmt_data_t fmt_data, std::integral arg_t>
 constexpr inline void format_arg(char* dest, arg_t arg) {
-    const_fmt_detail::format_int<arg_t, fmt_data>(dest, arg);
+    const_fmt_detail::format_int<fmt_data>(dest, arg);
 };
 
 template <fmt_data_t fmt_data, std::floating_point arg_t>
 constexpr inline void format_arg(char* dest, arg_t arg){
-    const_fmt_detail::format_float<arg_t, fmt_data>(dest, arg);
+    const_fmt_detail::format_float<fmt_data>(dest, arg);
 };
 
 // TODO: Error handling

const_fmt/format_impl.h

@@ -58,22 +58,40 @@ inline int do_count_digits(uint64_t n) {
     return t - (n < zero_or_powers_of_10[t]);
 }
 
-constexpr inline auto count_digits(uint64_t n) -> int {
+template <FormatType t_format_type>
+constexpr inline auto count_digits_base(uint64_t n) -> int {
+    if constexpr (t_format_type == FormatType::b) {
+        int result = 0;
+
+        while (n) {
+            n = n >> 1;
+            result += 1;
+        }
+
+        return result;
+    } else {
         if (!std::is_constant_evaluated()) {
             return do_count_digits(n);
         }
+
         return count_digits_fallback(n);
+    }
 }
 
 
-// Converts value in the range [0, 100) to a string.
-constexpr inline const char* digits2(size_t value) {
+// Converts value in the range [0, base^2) to a string.
+template <FormatType t_format_type>
+constexpr inline const char* digits2_base(size_t value) {
     // GCC generates slightly better code when value is pointer-size.
+    if constexpr (t_format_type == FormatType::b) {
+        return &"00011011"[value * 2];
+    } else {
         return &"0001020304050607080910111213141516171819"
                 "2021222324252627282930313233343536373839"
                 "4041424344454647484950515253545556575859"
                 "6061626364656667686970717273747576777879"
                 "8081828384858687888990919293949596979899"[value * 2];
+    }
 }
 
 
@@ -86,9 +104,13 @@ constexpr inline void copy2(char* dst, const char* src) {
     *dst   = static_cast<char>(*src);
 }
 
-template <typename uint_t>
-constexpr inline void format_decimal(char* out, uint_t value, int n_digits,
+
+template <FormatType t_format_type, typename uint_t>
+constexpr inline void format_base(char* out, uint_t value, int n_digits,
                                   int size) {
+    constexpr unsigned divisor = (t_format_type == FormatType::b) ? 2 : 10;
+    constexpr unsigned square_divisor = const_pow(divisor, 2);
+
     if (n_digits > size) {
         for (int i = 0; i < size; ++i) {
             *(out++) = 'f';
@@ -97,19 +119,20 @@ constexpr inline void format_decimal(char* out, uint_t value, int n_digits,
     }
 
     out += size;
-    while (value >= 100) {
+    while (value >= square_divisor) {
         out -= 2;
-        copy2(out, digits2(static_cast<size_t>(value % 100)));
-        value /= 100;
+        copy2(out, digits2_base<t_format_type>(
+                       static_cast<size_t>(value % square_divisor)));
+        value /= square_divisor;
     }
 
-    if (value < 10) {
+    if (value < divisor) {
         *--out = static_cast<char>('0' + value);
         return;
     }
 
     out -= 2;
-    copy2(out, digits2(static_cast<size_t>(value)));
+    copy2(out, digits2_base<t_format_type>(static_cast<size_t>(value)));
 }
 
 // returns {abs_value, was_negative}
@@ -139,18 +162,21 @@ constexpr std::pair<int_t, bool> get_abs_value(int_t value) {
  */
 
 
-template <std::unsigned_integral uint_t, fmt_data_t t_fmt_node>
+template <fmt_data_t t_fmt_node, std::unsigned_integral uint_t>
 constexpr inline void format_int(char* out, uint_t value) {
-    format_decimal(out, value, count_digits(value), t_fmt_node.length);
+    // format_decimal(out, value, count_digits(value), t_fmt_node.length);
+    format_base<t_fmt_node.type>(out, value, count_digits_base<t_fmt_node.type>(value),
+                                 t_fmt_node.length);
 }
 
-template <std::signed_integral int_t, fmt_data_t t_fmt_node>
+
+template <fmt_data_t t_fmt_node, std::signed_integral int_t>
 constexpr inline void format_int(char* out, int_t value) {
     const auto [abs_value, negative] = get_abs_value(value);
 
-    const std::size_t n_digits = count_digits(abs_value);
+    const std::size_t n_digits = count_digits_base<t_fmt_node.type>(abs_value);
 
-    format_decimal(out + 1 * (negative), abs_value, n_digits,
+    format_base<t_fmt_node.type>(out + 1 * (negative), abs_value, n_digits,
                                  t_fmt_node.length - 1 * (negative));
 
     if constexpr (t_fmt_node.has_zero_padding) {
@@ -169,21 +195,21 @@ constexpr inline void format_int(char* out, int_t value) {
  */
 
 
-template <std::floating_point float_t, fmt_data_t t_fmt_node>
+template <fmt_data_t t_fmt_node, std::floating_point float_t>
 constexpr inline void format_float(char* out, float_t value) {
     // clang-format off
     constexpr fmt_data_t fmt_node_integral = {
         t_fmt_node.has_zero_padding,                  // has_zero_padding
         t_fmt_node.length - t_fmt_node.precision - 1, // length
         t_fmt_node.precision,                         // ignored
-        t_fmt_node.type,                              // ignored
+        FormatType::d,                                // type
         t_fmt_node.position                           // ignored
     };
     constexpr fmt_data_t fmt_node_fractional = {
         true,                                         // has_zero_padding
         t_fmt_node.precision,                         // length
         t_fmt_node.precision,                         // ignored
-        t_fmt_node.type,                              // ignored
+        FormatType::d,                                // type
         t_fmt_node.position                           // ignored
     };
     // clang-format on
@@ -198,8 +224,8 @@ constexpr inline void format_float(char* out, float_t value) {
     const auto [fractional_abs, fractional_negative] =
         get_abs_value(fractional);
 
-    format_int<int, fmt_node_integral>(out, integral);
-    format_int<uint16_t, fmt_node_fractional>(
+    format_int<fmt_node_integral, int>(out, integral);
+    format_int<fmt_node_fractional, uint16_t>(
         out + t_fmt_node.length - t_fmt_node.precision, fractional_abs);
 }
 

examples/src/examples.cpp

@@ -5,7 +5,7 @@
 using namespace const_fmt;
 
 int main() {
-    constexpr auto s = "This is an integer: {:08}, and this is a float: {:09.4}"_const_fmt(12345, -86.2);
+    constexpr auto s = "This is an integer: {:08b}, and this is a float: {:09.4b}"_const_fmt(125u, -86.2);
 
     // Convert s (with a type of 'std::array<char, N>') into something
     // writable to std::cout

test/CMakeLists.txt

@@ -25,5 +25,6 @@ endmacro()
 
 package_add_test(utility_test src/utility.cpp)
 package_add_test(parse_test src/parse.cpp)
-package_add_test(format_test src/format.cpp)
+package_add_test(format_decimal_test src/format_decimal.cpp)
+package_add_test(format_binary_test src/format_binary.cpp)
 

test/src/format_binary.cpp

@@ -0,0 +1,59 @@
+#include <const_fmt/format.h>
+#include <gtest/gtest.h>
+
+
+using namespace const_fmt;
+using namespace const_fmt::const_fmt_detail;
+
+
+TEST(FormatBinary, positive_int) {
+    constexpr std::array<char, 8> control1   = {'0', '0', '0', '0',
+                                              '0', '0', '1', '0'};
+    constexpr std::array<char, 8> formatted1 = const_format<"{:08b}">(0b10);
+
+    constexpr std::array<char, 8> control2   = {' ', ' ', '1', '0',
+                                              '1', '0', '1', '0'};
+    constexpr std::array<char, 8> formatted2 = const_format<"{:8b}">(0b101010);
+
+    constexpr std::array<char, 8> control3   = {'0', '0', '0', '1',
+                                              '1', '0', '0', '1'};
+    constexpr std::array<char, 8> formatted3 = const_format<"{:08.4b}">(0b11001);
+
+    constexpr std::array<char, 4> control4   = {'1', '0', '1', '1'};
+    constexpr std::array<char, 4> formatted4 = const_format<"{:4b}">(0b1011);
+
+    constexpr std::array<char, 4> control5   = {'f', 'f', 'f', 'f'};
+    constexpr std::array<char, 4> formatted5 = const_format<"{:4b}">(0b10011);
+
+    EXPECT_EQ(control1, formatted1);
+    EXPECT_EQ(control2, formatted2);
+    EXPECT_EQ(control3, formatted3);
+    EXPECT_EQ(control4, formatted4);
+    EXPECT_EQ(control5, formatted5);
+}
+
+TEST(FormatBinary, negative_int) {
+    constexpr std::array<char, 8> control1   = {'-', '0', '0', '0',
+                                              '0', '0', '1', '0'};
+    constexpr std::array<char, 8> formatted1 = const_format<"{:08b}">(-0b10);
+
+    constexpr std::array<char, 8> control2   = {' ', '-', '1', '0',
+                                                '1', '0', '1', '0'};
+    constexpr std::array<char, 8> formatted2 = const_format<"{:8b}">(-0b101010);
+
+    constexpr std::array<char, 8> control3   = {'-', '0', '0', '1',
+                                              '0', '0', '1', '1'};
+    constexpr std::array<char, 8> formatted3 = const_format<"{:08.4b}">(-0b10011);
+
+    constexpr std::array<char, 5> control4   = {'-', '1', '1', '0', '1'};
+    constexpr std::array<char, 5> formatted4 = const_format<"{:5b}">(-0b1101);
+
+    constexpr std::array<char, 5> control5   = {'-', 'f', 'f', 'f', 'f'};
+    constexpr std::array<char, 5> formatted5 = const_format<"{:05b}">(-0b10101);
+
+    EXPECT_EQ(control1, formatted1);
+    EXPECT_EQ(control2, formatted2);
+    EXPECT_EQ(control3, formatted3);
+    EXPECT_EQ(control4, formatted4);
+    EXPECT_EQ(control5, formatted5);
+}

test/src/format_decimal.cpp

@@ -6,7 +6,7 @@ using namespace const_fmt;
 using namespace const_fmt::const_fmt_detail;
 
 
-TEST(Format, positive_int) {
+TEST(FormatDecimal, positive_int) {
     constexpr std::array<char, 8> control1   = {'0', '0', '0', '0',
                                               '0', '0', '0', '2'};
     constexpr std::array<char, 8> formatted1 = const_format<"{:08}">(2);
@@ -32,7 +32,7 @@ TEST(Format, positive_int) {
     EXPECT_EQ(control5, formatted5);
 }
 
-TEST(Format, negative_int) {
+TEST(FormatDecimal, negative_int) {
     constexpr std::array<char, 8> control1   = {'-', '0', '0', '0',
                                               '0', '0', '0', '2'};
     constexpr std::array<char, 8> formatted1 = const_format<"{:08}">(-2);
@@ -58,7 +58,7 @@ TEST(Format, negative_int) {
     EXPECT_EQ(control5, formatted5);
 }
 
-TEST(Format, positive_float) {
+TEST(FormatDecimal, positive_float) {
     constexpr std::array<char, 8> control1   = {'0', '0', '2', '.',
                                               '3', '4', '5', '6'};
     constexpr std::array<char, 8> formatted1 = const_format<"{:08.4}">(2.3456);
@@ -82,7 +82,7 @@ TEST(Format, positive_float) {
     EXPECT_EQ(control4, formatted4);
 }
 
-TEST(Format, negative_float) {
+TEST(FormatDecimal, negative_float) {
     constexpr std::array<char, 8> control1   = {'-', '0', '2', '.',
                                                 '3', '4', '5', '6'};
     constexpr std::array<char, 8> formatted1 = const_format<"{:08.4}">(-2.3456);
@@ -101,8 +101,3 @@ TEST(Format, negative_float) {
     EXPECT_EQ(control2, formatted2);
     EXPECT_EQ(control3, formatted3);
 }
-//
-// TEST(Format, string) {
-//    // TODO
-//    EXPECT_EQ(true, false);
-//}