From 02b4c2c20958c9fb04e657c58c41f3fe1b550f49 Mon Sep 17 00:00:00 2001
From: Jens Ahrensfeld <jens@jayfield.org>
Date: Fri, 11 Jan 2019 16:39:37 +0000
Subject: [PATCH] -a dded

git-svn-id: http://moon:8086/svn/software/trunk/projects/GnuRadio@404 b431acfa-c32f-4a4a-93f1-934dc6c82436
---
 gr-jay/lib/PocsagDecoder.cpp | 167 +++++++++++++++++++++++++++++++++++
 gr-jay/lib/PocsagDecoder.hpp |  47 ++++++++++
 2 files changed, 214 insertions(+)
 create mode 100644 gr-jay/lib/PocsagDecoder.cpp
 create mode 100644 gr-jay/lib/PocsagDecoder.hpp

diff --git a/gr-jay/lib/PocsagDecoder.cpp b/gr-jay/lib/PocsagDecoder.cpp
new file mode 100644
index 0000000..40126c6
--- /dev/null
+++ b/gr-jay/lib/PocsagDecoder.cpp
@@ -0,0 +1,167 @@
+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+/* 
+ * File:   PocsagDecoder.cpp
+ * Author: jens
+ * 
+ * Created on 11. Januar 2019, 17:20
+ */
+
+#include "PocsagDecoder.hpp"
+
+const char numericChar[16] = 
+{
+	'0', '1', '2', '3', 
+	'4', '5', '6', '7', 
+	'8', '9', '.', 'U', 
+	' ', '-', ']', '[', 
+};
+
+PocsagDecoder::PocsagDecoder()
+: state(Sync)
+, dataCount(0)
+, msgPos(0)
+, msgWord(0)
+, func(0)
+, msgActive(0)
+{
+}
+
+PocsagDecoder::PocsagDecoder(const PocsagDecoder& orig)
+{
+}
+
+PocsagDecoder::~PocsagDecoder()
+{
+}
+
+void PocsagDecoder::messageFinish()
+{
+	if (msgActive)
+	{
+		msgActive = 0;
+		msgPos = 0;
+		msgWord = 0;
+		fprintf(stderr, "\n");
+	}
+}
+
+size_t PocsagDecoder::process(uint8_t const *pData, size_t size)
+{
+	size_t remain = size;
+	size_t numProcessed = 0;
+	while(remain >= 4)
+	{
+		int incr = 4;
+		uint32_t word 
+				= (uint32_t)pData[0] << 24 & 0xFF000000
+				| (uint32_t)pData[1] << 16 & 0x00FF0000
+				| (uint32_t)pData[2] <<  8 & 0x0000FF00
+				| (uint32_t)pData[3] <<  0 & 0x000000FF;
+	
+//		printf ("word=%08X\n", word);
+
+		State stateNext = state;
+		switch(state)
+		{
+			case Sync:
+				if (word == 0x7CD215D8)
+				{
+					stateNext = Data;
+					dataCount = 0x00;
+				}
+				else
+				{
+					incr = 1;
+				}
+				break;
+			case Data:
+				if (word == 0x7CD215D8)
+				{
+					dataCount = 0x00;
+					break;
+				}
+				if (word & 0x80000000)
+				{
+					// Message word
+					if (func == 0x00)
+					{
+						// Numeric
+						msgActive = 1;
+						for (size_t i=1; i < 21; i++)
+						{
+							uint32_t bit = 0x80000000 & (word << i);
+							msgWord >>= 1;
+
+							msgWord |= (uint8_t)(0x8*(bit != 0));
+							msgPos++;
+							if (msgPos == 4)
+							{
+								fprintf(stderr, "%c", numericChar[msgWord]);
+								msgPos = 0;
+								msgWord = 0;
+							}
+						}
+					}
+					if (func == 0x03)
+					{
+						// Alpha numeric
+						msgActive = 1;
+						for (size_t i=1; i < 21; i++)
+						{
+							uint32_t bit = 0x80000000 & (word << i);
+							msgWord >>= 1;
+
+							msgWord |= (uint8_t)(0x40*(bit != 0));
+							msgPos++;
+							if (msgPos == 7)
+							{
+								if (msgWord != 0x04)
+								{
+									fprintf(stderr, "%c", msgWord);
+									msgPos = 0;
+									msgWord = 0;
+								}
+							}
+						}
+					}
+				}
+				else
+				{
+					if (word == 0x7A89C197)
+					{
+						// Idle
+						messageFinish();
+					}
+					else
+					{
+						// Address word
+						messageFinish();
+						uint32_t addr = (word >> 13) & 0x3FFFF; 
+						func = (word >> 11) & 0x03; 
+						fprintf(stderr, "%02X: [%07u](%02X): ", (uint8_t)(dataCount), 8*addr+dataCount/2, func);
+					}
+				}
+				dataCount++;
+				if (dataCount == 0x10)
+				{
+					stateNext = Sync;
+					dataCount = 0;
+//					incr = 1;
+				}
+				break;
+	
+		}
+		pData += incr;
+		remain -= incr;
+		state = stateNext;
+		numProcessed += incr;
+		
+	}
+	
+	return numProcessed;
+}
\ No newline at end of file
diff --git a/gr-jay/lib/PocsagDecoder.hpp b/gr-jay/lib/PocsagDecoder.hpp
new file mode 100644
index 0000000..21bbccd
--- /dev/null
+++ b/gr-jay/lib/PocsagDecoder.hpp
@@ -0,0 +1,47 @@
+/*
+ * To change this license header, choose License Headers in Project Properties.
+ * To change this template file, choose Tools | Templates
+ * and open the template in the editor.
+ */
+
+/* 
+ * File:   PocsagDecoder.hpp
+ * Author: jens
+ *
+ * Created on 11. Januar 2019, 17:20
+ */
+
+#ifndef POCSAGDECODER_HPP
+#define POCSAGDECODER_HPP
+
+#include <cstdlib>
+#include <cstdio>
+#include <cstdint>
+
+class PocsagDecoder
+{
+public:
+	PocsagDecoder();
+	PocsagDecoder(const PocsagDecoder& orig);
+	virtual ~PocsagDecoder();
+	size_t process(uint8_t const *pData, size_t size); 
+
+private:
+	enum State
+	{
+		Sync,
+		Data
+	};
+
+	State state = Sync;
+	size_t dataCount;
+	size_t msgPos = 0;
+	uint8_t msgWord = 0;
+	uint32_t func = 0;
+	bool msgActive = 0;
+
+	void messageFinish();
+};
+
+#endif /* POCSAGDECODER_HPP */
+