From 6438aa81c1e75ae06c1e833bcdad0ab4d5fc913b Mon Sep 17 00:00:00 2001
From: BlackMark <me@blackmark.me>
Date: Sat, 3 Aug 2019 19:49:01 +0200
Subject: [PATCH] Added padding and case selection to txNumber

---
 uart.hpp | 41 ++++++++++++++++++++++++++++++++---------
 1 file changed, 32 insertions(+), 9 deletions(-)

diff --git a/uart.hpp b/uart.hpp
index 91326ab..a3cefe7 100644
--- a/uart.hpp
+++ b/uart.hpp
@@ -22,11 +22,6 @@ static constexpr size_t cntDigits()
 	T num = limit;
 	size_t cnt = 0;
 
-	if (num < 0) {
-		num = -num;
-		++cnt;
-	}
-
 	do {
 		num /= Base;
 		++cnt;
@@ -38,8 +33,23 @@ static constexpr size_t cntDigits()
 template <typename T, size_t Base>
 static constexpr size_t maxNumDigits()
 {
-	T minDigits = cntDigits<T, util::NumericLimits<T>::min(), Base>();
-	T maxDigits = cntDigits<T, util::NumericLimits<T>::max(), Base>();
+	constexpr T minVal = util::NumericLimits<T>::min();
+	constexpr T maxVal = util::NumericLimits<T>::max();
+
+	T minDigits = cntDigits<T, minVal, Base>() + ((minVal < 0) ? 1 : 0);
+	T maxDigits = cntDigits<T, maxVal, Base>() + ((maxVal < 0) ? 1 : 0);
+
+	return (minDigits < maxDigits) ? maxDigits : minDigits;
+}
+
+template <typename T, size_t Base>
+static constexpr size_t maxPadding()
+{
+	constexpr T minVal = util::NumericLimits<T>::min();
+	constexpr T maxVal = util::NumericLimits<T>::max();
+
+	T minDigits = cntDigits<T, minVal, Base>();
+	T maxDigits = cntDigits<T, maxVal, Base>();
 
 	return (minDigits < maxDigits) ? maxDigits : minDigits;
 }
@@ -111,14 +121,17 @@ class Uart {
 			txByte(ch);
 	}
 
-	template <typename T, size_t Base = 10>
+	template <typename T, size_t Base = 10, size_t Padding = 0, char PadChar = '0', bool LowerCase = true>
 	static void txNumber(const T &val)
 	{
 		static_assert(util::is_integral_v<T>, "Only supported on integral types");
 		static_assert(Base >= 2, "Numbers with bases less than 2 make no sense");
 		static_assert(Base <= 16, "Numbers with bases higher than 16 are not supported");
+		static_assert(Padding <= detail::maxPadding<T, Base>(), "Cannot pad more than maximum length of number");
 
+		constexpr char alphaChar = (LowerCase) ? 'a' : 'A';
 		constexpr size_t numDigits = detail::maxNumDigits<T, Base>();
+
 		data_t buffer[numDigits];
 		data_t *bufEnd = buffer + numDigits - 1;
 
@@ -131,10 +144,20 @@ class Uart {
 
 		do {
 			data_t lastDigit = digits % Base;
-			*bufEnd-- = (lastDigit < 10) ? ('0' + lastDigit) : ('a' + lastDigit - 10);
+			*bufEnd-- = (lastDigit < 10) ? ('0' + lastDigit) : (alphaChar + lastDigit - 10);
 			digits /= Base;
 		} while (digits > 0);
 
+		if (Padding > 0) {
+			size_t strLen = buffer + numDigits - (bufEnd + 1);
+
+			if (Padding > strLen) {
+				for (size_t i = Padding; i > strLen && bufEnd >= buffer; --i) {
+					*bufEnd-- = PadChar;
+				}
+			}
+		}
+
 		for (data_t *buf = bufEnd + 1; buf < buffer + numDigits; ++buf)
 			txByte(*buf);
 	}