From 2933676ea26d24ae0e2597b138335e3b50d6af57 Mon Sep 17 00:00:00 2001
From: Andreas Tsouchlos <an.tsouchlos@gmail.com>
Date: Tue, 15 Feb 2022 11:34:49 +0100
Subject: [PATCH] Fixed bug in hex formatting, wrote tests for hex int
 formatting

---
 const_fmt/format_impl.h   |  4 +--
 examples/src/examples.cpp |  2 +-
 test/CMakeLists.txt       |  1 +
 test/src/format_hex.cpp   | 59 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 63 insertions(+), 3 deletions(-)
 create mode 100644 test/src/format_hex.cpp

diff --git a/const_fmt/format_impl.h b/const_fmt/format_impl.h
index 2bbc9be..8ca5143 100644
--- a/const_fmt/format_impl.h
+++ b/const_fmt/format_impl.h
@@ -101,7 +101,7 @@ constexpr inline const char* digits2_base(size_t value) {
             return &"000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
                     "202122232425262728292A2B2C2D2E2F303132333435363738393A3B3C3D3E3F"
                     "404142434445464748494A4B4C4D4E4F505152535455565758595A5B5C5D5E5F"
-                    "606162636465666768696A6B6C6D6E6F707172737475767778796A6B6C6D6E6F"
+                    "606162636465666768696A6B6C6D6E6F707172737475767778797A7B7C7D7E7F"
                     "808182838485868788898A8B8C8D8E8F909192939495969798999A9B9C9D9E9F"
                     "A0A1A2A3A4A5A6A7A8A9AAABACADAEAFB0B1B2B3B4B5B6B7B8B9BABBBCBDBEBF"
                     "C0C1C2C3C4C5C6C7C8C9CACBCCCDCECFD0D1D2D3D4D5D6D7D8D9DADBDCDDDEDF"
@@ -161,7 +161,7 @@ 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;
     }
 
diff --git a/examples/src/examples.cpp b/examples/src/examples.cpp
index 911f63c..e955122 100644
--- a/examples/src/examples.cpp
+++ b/examples/src/examples.cpp
@@ -5,7 +5,7 @@
 using namespace const_fmt;
 
 int main() {
-    constexpr auto s = "This is an integer: {:08x}, 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
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index c2818fe..13950f3 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -28,4 +28,5 @@ 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)
 
diff --git a/test/src/format_hex.cpp b/test/src/format_hex.cpp
new file mode 100644
index 0000000..6735fd5
--- /dev/null
+++ b/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);
+}