From a3d76a138ddb9e5c0e7607aae38248ef0b33959b Mon Sep 17 00:00:00 2001
From: BlackMark <me@blackmark.me>
Date: Fri, 2 Aug 2019 18:20:06 +0200
Subject: [PATCH] Implemented peeking with and without data for interrupt and
 blocking mode

---
 hardware.hpp  |  9 +++++++++
 hardware0.hpp | 29 ++++++++++++++++++++++++++---
 hardware1.hpp | 29 ++++++++++++++++++++++++++---
 uart.hpp      |  7 ++++++-
 4 files changed, 67 insertions(+), 7 deletions(-)

diff --git a/hardware.hpp b/hardware.hpp
index 96f3c2e..1aec066 100644
--- a/hardware.hpp
+++ b/hardware.hpp
@@ -73,6 +73,15 @@ class Hardware {
 		*Registers::IO_REG = byte;
 	}
 
+	static bool peekBlocking() FORCE_INLINE
+	{
+		if (*Registers::CTRL_STAT_REG_A & (1 << CtrlFlagsA::RECEIVE_COMPLETE)) {
+			return true;
+		}
+
+		return false;
+	}
+
 	static void enableDataRegEmptyInt() FORCE_INLINE
 	{
 		*Registers::CTRL_STAT_REG_B |= (1 << CtrlFlagsB::DATA_REG_EMPTY_INT_ENABLE);
diff --git a/hardware0.hpp b/hardware0.hpp
index 62ab024..0dc82e4 100644
--- a/hardware0.hpp
+++ b/hardware0.hpp
@@ -101,7 +101,17 @@ class Hardware0 {
 		return HardwareImpl::rxByteBlocking(byte);
 	}
 
-	static data_t peek() FORCE_INLINE {}
+	static bool peek(data_t &byte) FORCE_INLINE
+	{
+		static_cast<void>(byte);
+		static_assert(driven == Driven::BLOCKING, "Peek with data is not supported in blocking mode");
+		return false;
+	}
+
+	static bool peek() FORCE_INLINE
+	{
+		return HardwareImpl::peekBlocking();
+	}
 
   private:
 	using HardwareImpl = detail::Hardware<detail::Registers0, detail::ControlFlagsA0, detail::ControlFlagsB0,
@@ -140,14 +150,27 @@ class Hardware0<mode, cfg, Driven::INTERRUPT> {
 			return false;
 
 		uint8_t tmpTail = (sm_rxBuf.tail + 1) % RX_BUFFER_SIZE;
-
 		byte = sm_rxBuf.buf[tmpTail];
 		sm_rxBuf.tail = tmpTail;
 
 		return true;
 	}
 
-	static data_t peek() FORCE_INLINE {}
+	static bool peek(data_t &byte) FORCE_INLINE
+	{
+		if (sm_rxBuf.head == sm_rxBuf.tail)
+			return false;
+
+		uint8_t tmpTail = (sm_rxBuf.tail + 1) % RX_BUFFER_SIZE;
+		byte = sm_rxBuf.buf[tmpTail];
+
+		return true;
+	}
+
+	static bool peek() FORCE_INLINE
+	{
+		return (sm_rxBuf.head != sm_rxBuf.tail);
+	}
 
   private:
 	using HardwareImpl = detail::Hardware<detail::Registers0, detail::ControlFlagsA0, detail::ControlFlagsB0,
diff --git a/hardware1.hpp b/hardware1.hpp
index 0f0f60e..51360e9 100644
--- a/hardware1.hpp
+++ b/hardware1.hpp
@@ -105,7 +105,17 @@ class Hardware1 {
 		return HardwareImpl::rxByteBlocking(byte);
 	}
 
-	static data_t peek() FORCE_INLINE {}
+	static bool peek(data_t &byte) FORCE_INLINE
+	{
+		static_cast<void>(byte);
+		static_assert(driven != Driven::BLOCKING, "Peek with data is not supported in blocking mode");
+		return false;
+	}
+
+	static bool peek() FORCE_INLINE
+	{
+		return HardwareImpl::peekBlocking();
+	}
 
   private:
 	using HardwareImpl = detail::Hardware<detail::Registers1, detail::ControlFlagsA1, detail::ControlFlagsB1,
@@ -144,14 +154,27 @@ class Hardware1<mode, cfg, Driven::INTERRUPT> {
 			return false;
 
 		uint8_t tmpTail = (sm_rxBuf.tail + 1) % RX_BUFFER_SIZE;
-
 		byte = sm_rxBuf.buf[tmpTail];
 		sm_rxBuf.tail = tmpTail;
 
 		return true;
 	}
 
-	static data_t peek() FORCE_INLINE {}
+	static bool peek(data_t &byte) FORCE_INLINE
+	{
+		if (sm_rxBuf.head == sm_rxBuf.tail)
+			return false;
+
+		uint8_t tmpTail = (sm_rxBuf.tail + 1) % RX_BUFFER_SIZE;
+		byte = sm_rxBuf.buf[tmpTail];
+
+		return true;
+	}
+
+	static bool peek() FORCE_INLINE
+	{
+		return (sm_rxBuf.head != sm_rxBuf.tail);
+	}
 
   private:
 	using HardwareImpl = detail::Hardware<detail::Registers1, detail::ControlFlagsA1, detail::ControlFlagsB1,
diff --git a/uart.hpp b/uart.hpp
index b64bab0..3fd9a00 100644
--- a/uart.hpp
+++ b/uart.hpp
@@ -45,7 +45,12 @@ class Uart {
 		return Driver::rxByte(byte);
 	}
 
-	static typename Driver::data_t peek()
+	static bool peek(typename Driver::data_t &byte)
+	{
+		return Driver::peek(byte);
+	}
+
+	static bool peek()
 	{
 		return Driver::peek();
 	}