Merge pull request 'feature/int_hex' (#6) from feature/int_hex into master

Reviewed-on: http://git.mercurial-manifold.eu/an.tsouchlos/const_fmt/pulls/6

const_fmt/format_impl.h

@@ -69,11 +69,21 @@ constexpr inline auto count_digits_base(uint64_t n) -> int {
 
         return result;
     } else {
-        if (!std::is_constant_evaluated()) {
+        if constexpr (t_format_type == FormatType::x) {
-            return do_count_digits_decimal(n);
+            int result = 0;
-        }
 
-        return count_digits_decimal_fallback(n);
+            while (n) {
+                n = n >> 4;
+                result += 1;
+            }
+
+            return (result + count_digits_base<FormatType::b>(n));
+        } else {
+            if (!std::is_constant_evaluated()) {
+                return do_count_digits_decimal(n);
+            }
+            return count_digits_decimal_fallback(n);
+        }
     }
 }
 
@@ -85,11 +95,24 @@ constexpr inline const char* digits2_base(size_t value) {
     if constexpr (t_format_type == FormatType::b) {
         return &"00011011"[value * 2];
     } else {
-        return &"0001020304050607080910111213141516171819"
+        if constexpr (t_format_type == FormatType::x) {
-                "2021222324252627282930313233343536373839"
+            // clang-format off
-                "4041424344454647484950515253545556575859"
+            return &"000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
-                "6061626364656667686970717273747576777879"
+                    "202122232425262728292A2B2C2D2E2F303132333435363738393A3B3C3D3E3F"
-                "8081828384858687888990919293949596979899"[value * 2];
+                    "404142434445464748494A4B4C4D4E4F505152535455565758595A5B5C5D5E5F"
+                    "606162636465666768696A6B6C6D6E6F707172737475767778797A7B7C7D7E7F"
+                    "808182838485868788898A8B8C8D8E8F909192939495969798999A9B9C9D9E9F"
+                    "A0A1A2A3A4A5A6A7A8A9AAABACADAEAFB0B1B2B3B4B5B6B7B8B9BABBBCBDBEBF"
+                    "C0C1C2C3C4C5C6C7C8C9CACBCCCDCECFD0D1D2D3D4D5D6D7D8D9DADBDCDDDEDF"
+                    "E0E1E2E3E4E5E6E7E8E9EAEBECEDEEEFF0F1F2F3F4F5F6F7F8F9FAFBFCFDFEFF"[value * 2];
+            // clang-format on
+        } else {
+            return &"0001020304050607080910111213141516171819"
+                    "2021222324252627282930313233343536373839"
+                    "4041424344454647484950515253545556575859"
+                    "6061626364656667686970717273747576777879"
+                    "8081828384858687888990919293949596979899"[value * 2];
+        }
     }
 }
 
@@ -103,11 +126,22 @@ constexpr inline void copy2(char* dst, const char* src) {
     *dst   = static_cast<char>(*src);
 }
 
+template <FormatType t_format_type>
+consteval inline unsigned get_base_divisor() {
+    switch (t_format_type) {
+    case FormatType::b:
+        return 2;
+    case FormatType::x:
+        return 16;
+    default:
+        return 10;
+    }
+}
 
 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 divisor        = get_base_divisor<t_format_type>();
     constexpr unsigned square_divisor = const_pow(divisor, 2);
 
     if (n_digits > size) {
@@ -126,7 +160,7 @@ constexpr inline void format_base(char* out, uint_t value, int n_digits,
     }
 
     if (value < divisor) {
-        *--out = static_cast<char>('0' + value);
+        *--out = digits2_base<t_format_type>(value*divisor)[0];
         return;
     }
 
@@ -164,7 +198,6 @@ constexpr std::pair<int_t, bool> get_abs_value(int_t value) {
 
 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_base<t_fmt_node.type>(out, value,
                                  count_digits_base<t_fmt_node.type>(value),
                                  t_fmt_node.length);

examples/src/examples.cpp

@@ -5,7 +5,7 @@
 using namespace const_fmt;
 
 int main() {
-    constexpr auto s = "This is an integer: {:08b}, and this is a float: {:09.4b}"_const_fmt(125u, -86.2);
+    constexpr auto s = "This is an integer: {:08x}, and this is a float: {:09.4b}"_const_fmt(122u, -86.2);
 
     // Convert s (with a type of 'std::array<char, N>') into something
     // writable to std::cout

test/CMakeLists.txt

@@ -25,6 +25,8 @@ endmacro()
 
 package_add_test(utility_test src/utility.cpp)
 package_add_test(parse_test src/parse.cpp)
+package_add_test(format_utility_test src/format_utility.cpp)
 package_add_test(format_decimal_test src/format_decimal.cpp)
 package_add_test(format_binary_test src/format_binary.cpp)
+package_add_test(format_hex_test src/format_hex.cpp)
 

test/src/format_hex.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(FormatHex, positive_int) {
+    constexpr std::array<char, 8> control1   = {'0', '0', '0', '0',
+                                                '0', '0', '1', '0'};
+    constexpr std::array<char, 8> formatted1 = const_format<"{:08x}">(0x10);
+
+    constexpr std::array<char, 8> control2   = {' ', ' ', ' ', 'F',
+                                                'F', 'A', '7', '6'};
+    constexpr std::array<char, 8> formatted2 = const_format<"{:8x}">(0xffa76);
+
+    constexpr std::array<char, 8> control3   = {'0', '0', '0', '0',
+                                                'B', 'C', 'E', 'F'};
+    constexpr std::array<char, 8> formatted3 = const_format<"{:08.4x}">(0xbcef);
+
+    constexpr std::array<char, 4> control4   = {'A', 'D', '0', '1'};
+    constexpr std::array<char, 4> formatted4 = const_format<"{:4x}">(0xad01);
+
+    constexpr std::array<char, 4> control5   = {'f', 'f', 'f', 'f'};
+    constexpr std::array<char, 4> formatted5 = const_format<"{:4x}">(0x12345);
+
+    EXPECT_EQ(control1, formatted1);
+    EXPECT_EQ(control2, formatted2);
+    EXPECT_EQ(control3, formatted3);
+    EXPECT_EQ(control4, formatted4);
+    EXPECT_EQ(control5, formatted5);
+}
+
+TEST(FormatHex, negative_int) {
+    constexpr std::array<char, 8> control1   = {'-', '0', '0', '0',
+                                                '0', '0', '1', '0'};
+    constexpr std::array<char, 8> formatted1 = const_format<"{:08x}">(-0x10);
+
+    constexpr std::array<char, 8> control2   = {' ', ' ', '-', 'F',
+                                                'F', 'A', '7', '6'};
+    constexpr std::array<char, 8> formatted2 = const_format<"{:8x}">(-0xffa76);
+
+    constexpr std::array<char, 8> control3   = {'-', '0', '0', '0',
+                                                'B', 'C', 'E', 'F'};
+    constexpr std::array<char, 8> formatted3 = const_format<"{:08.4x}">(-0xbcef);
+
+    constexpr std::array<char, 4> control4   = {'-', 'A', 'D', '1'};
+    constexpr std::array<char, 4> formatted4 = const_format<"{:4x}">(-0xad1);
+
+    constexpr std::array<char, 4> control5   = {'-', 'f', 'f', 'f'};
+    constexpr std::array<char, 4> formatted5 = const_format<"{:04x}">(-0x1234);
+
+    EXPECT_EQ(control1, formatted1);
+    EXPECT_EQ(control2, formatted2);
+    EXPECT_EQ(control3, formatted3);
+    EXPECT_EQ(control4, formatted4);
+    EXPECT_EQ(control5, formatted5);
+}

test/src/format_utility.cpp

@@ -0,0 +1,44 @@
+#include <const_fmt/format_impl.h>
+#include <limits>
+#include <gtest/gtest.h>
+
+
+using namespace const_fmt;
+using namespace const_fmt::const_fmt_detail;
+
+
+TEST(FormatUtility, count_digits_base_decimal) {
+    constexpr unsigned length1 = count_digits_base<FormatType::d>(123);
+    constexpr unsigned length2 = count_digits_base<FormatType::d>(std::numeric_limits<uint64_t>::max());
+    constexpr unsigned length3 = count_digits_base<FormatType::d>(10000011);
+    constexpr unsigned length4 = count_digits_base<FormatType::d>(1);
+
+    EXPECT_EQ(length1, 3);
+    EXPECT_EQ(length2, 20);
+    EXPECT_EQ(length3, 8);
+    EXPECT_EQ(length4, 1);
+}
+
+TEST(FormatUtility, count_digits_base_binary) {
+    constexpr unsigned length1 = count_digits_base<FormatType::b>(0b1001);
+    constexpr unsigned length2 = count_digits_base<FormatType::b>(std::numeric_limits<uint64_t>::max());
+    constexpr unsigned length3 = count_digits_base<FormatType::b>(0b10000001);
+    constexpr unsigned length4 = count_digits_base<FormatType::b>(0b01);
+
+    EXPECT_EQ(length1, 4);
+    EXPECT_EQ(length2, 64);
+    EXPECT_EQ(length3, 8);
+    EXPECT_EQ(length4, 1);
+}
+
+TEST(FormatUtility, count_digits_base_hex) {
+    constexpr unsigned length1 = count_digits_base<FormatType::x>(0x123);
+    constexpr unsigned length2 = count_digits_base<FormatType::x>(std::numeric_limits<uint64_t>::max());
+    constexpr unsigned length3 = count_digits_base<FormatType::x>(0x1000000f);
+    constexpr unsigned length4 = count_digits_base<FormatType::x>(0x01);
+
+    EXPECT_EQ(length1, 3);
+    EXPECT_EQ(length2, 16);
+    EXPECT_EQ(length3, 8);
+    EXPECT_EQ(length4, 1);
+}