#71 Fixed 0 padding bug and added fast paths for 2 and 3 digit numbers

Author: ChristianPanov

lwlog/include/details/os/datetime_utility.h

@@ -37,8 +37,6 @@ namespace lwlog::details::os::datetime
 					}
 
 					return -bias / 60;
-
-					return -tz_info.Bias / 60;
 			#else
 					const std::time_t now{ std::time(nullptr) };
 
@@ -70,7 +68,9 @@ namespace lwlog::details::os::datetime
     struct timestamp_builder
     {
     public:
+		template<std::uint8_t Width>
 		timestamp_builder& append(std::size_t value);
+
 		timestamp_builder& append_ampm(std::size_t hour);
 		timestamp_builder& separate(char separator);
 

lwlog/include/details/os/datetime_utility_impl.h

@@ -1,4 +1,4 @@
-#pragma once
+#pragma once
 
 #include "details/memory_buffer.h"
 #include "datetime_utility.h"
@@ -19,23 +19,48 @@ namespace lwlog::details::os::datetime
 	}
 
 	template<std::size_t Size>
+	template<std::uint8_t Width>
 	timestamp_builder<Size>& timestamp_builder<Size>::append(std::size_t value)
 	{
-		if (value <= 9)
+		std::size_t remaining{ value };
+
+		if constexpr (Width == 2) 
 		{
-			m_buffer[m_pos++] = '0';
+			m_buffer[m_pos + 1] = char('0' + (remaining % 10)); remaining /= 10;
+			m_buffer[m_pos + 0] = char('0' + (remaining % 10));
+
+			m_pos += 2;
 		}
+		else if constexpr (Width == 3) 
+		{
+			m_buffer[m_pos + 2] = char('0' + (remaining % 10)); remaining /= 10;
+			m_buffer[m_pos + 1] = char('0' + (remaining % 10)); remaining /= 10;
+			m_buffer[m_pos + 0] = char('0' + (remaining % 10));
 
-		const auto [ptr, ec]{ std::to_chars(m_buffer + m_pos, m_buffer + Size, value) };
-		m_pos = ptr - m_buffer;
+			m_pos += 3;
+		}
+		else
+		{
+			std::size_t write_pos{ m_pos + Width };
+
+			for (std::uint8_t n = Width; n--;)
+			{
+				m_buffer[--write_pos] = char('0' + (remaining % 10));
+				remaining /= 10;
+			}
+
+			m_pos += Width;
+		}
 
 		return *this;
 	}
 
 	template<std::size_t Size>
 	timestamp_builder<Size>& timestamp_builder<Size>::append_ampm(std::size_t hour)
 	{
-		std::memcpy(m_buffer + m_pos, hour >= 12 ? "pm" : "am", 2);
+		m_buffer[m_pos] = (hour >= 12) ? 'p' : 'a';
+		m_buffer[m_pos + 1] = 'm';
+
 		m_pos += 2;
 
 		return *this;

lwlog/include/details/pattern/formatters.h

@@ -156,11 +156,11 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::date, 
 				os::datetime::timestamp_builder<10>()
-				.append(time_point.year)
+				.append<2>(time_point.year)
 				.separate('-')
-				.append(time_point.month)
+				.append<2>(time_point.month)
 				.separate('-')
-				.append(time_point.day).data()
+				.append<2>(time_point.day).data()
 			);
 		}
 	};
@@ -175,11 +175,11 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::date_short, 
 				os::datetime::timestamp_builder<8>()
-				.append(time_point.month)
+				.append<2>(time_point.month)
 				.separate('/')
-				.append(time_point.day)
+				.append<2>(time_point.day)
 				.separate('/')
-				.append(time_point.year % 100).data()
+				.append<2>(time_point.year % 100).data()
 			);
 		}
 	};
@@ -194,7 +194,7 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::year, 
 				os::datetime::timestamp_builder<4>()
-				.append(time_point.year)
+				.append<2>(time_point.year)
 				.data()
 			);
 		}
@@ -210,7 +210,7 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::year_short, 
 				os::datetime::timestamp_builder<2>()
-				.append(time_point.year % 100)
+				.append<2>(time_point.year % 100)
 				.data()
 			);
 		}
@@ -226,7 +226,7 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::month, 
 				os::datetime::timestamp_builder<2>()
-				.append(time_point.month)
+				.append<2>(time_point.month)
 				.data()
 			);
 		}
@@ -274,7 +274,7 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::day,
 				os::datetime::timestamp_builder<2>()
-				.append(time_point.day)
+				.append<2>(time_point.day)
 				.data()
 			);
 		}
@@ -322,11 +322,11 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::time, 
 				os::datetime::timestamp_builder<10>()
-				.append(time_point.hour)
+				.append<2>(time_point.hour)
 				.separate(':')
-				.append(time_point.minute)
+				.append<2>(time_point.minute)
 				.separate(':')
-				.append(time_point.second)
+				.append<2>(time_point.second)
 				.data()
 			);
 		}
@@ -342,9 +342,9 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::hour_clock_24, 
 				os::datetime::timestamp_builder<5>()
-				.append(time_point.hour)
+				.append<2>(time_point.hour)
 				.separate(':')
-				.append(time_point.minute)
+				.append<2>(time_point.minute)
 				.data()
 			);
 		}
@@ -360,11 +360,11 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::hour_clock_12, 
 				os::datetime::timestamp_builder<10>()
-				.append(time_point.hour)
+				.append<2>(time_point.hour)
 				.separate(':')
-				.append(time_point.minute)
+				.append<2>(time_point.minute)
 				.separate(':')
-				.append(time_point.second)
+				.append<2>(time_point.second)
 				.append_ampm(time_point.hour)
 				.data()
 			);
@@ -397,7 +397,7 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::hour_24,
 				os::datetime::timestamp_builder<2>()
-				.append(time_point.hour)
+				.append<2>(time_point.hour)
 				.data()
 			);
 		}
@@ -413,7 +413,7 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::hour_12,
 				os::datetime::timestamp_builder<2>()
-				.append(os::datetime::to_12h(time_point.hour))
+				.append<2>(os::datetime::to_12h(time_point.hour))
 				.data()
 			);
 		}
@@ -429,7 +429,7 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::minute,
 				os::datetime::timestamp_builder<2>()
-				.append(time_point.minute)
+				.append<2>(time_point.minute)
 				.data()
 			);
 		}
@@ -445,7 +445,7 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::second,
 				os::datetime::timestamp_builder<2>()
-				.append(time_point.second)
+				.append<2>(time_point.second)
 				.data()
 			);
 		}
@@ -461,7 +461,7 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::millisecond,
 				os::datetime::timestamp_builder<3>()
-				.append(time_point.millisecond)
+				.append<3>(time_point.millisecond)
 				.data()
 			);
 		}
@@ -477,7 +477,7 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::microsecond,
 				os::datetime::timestamp_builder<6>()
-				.append(time_point.microsecond)
+				.append<6>(time_point.microsecond)
 				.data()
 			);
 		}
@@ -493,7 +493,7 @@ namespace lwlog::details
 
 			formatter<BufferLimits>::format_attribute(pattern_buffer, conv_buffer, flag::nanosecond,
 				os::datetime::timestamp_builder<9>()
-				.append(time_point.nanosecond)
+				.append<9>(time_point.nanosecond)
 				.data()
 			);
 		}