// --------------------------------------------------------------
#include <string.h>
#include <math.h>
#include <stdint.h>
#include "DeSymbolizer.hpp"


DeSymbolizer::DeSymbolizer()
: Processor::Block(1, 1)
, m_dataBitCount(0)
, m_lastSymbol(0)
, m_symbolMask(0)
, m_nBitsPerSym(0)
{
	setNumBitsPerSymbol(8);
}

void DeSymbolizer::setNumBitsPerSymbol(uint32_t nBitsPerSym)
{
	m_nBitsPerSym = nBitsPerSym;
	m_symbolMask = 0;
	for(uint32_t k=0; k < nBitsPerSym; k++)
	{
		m_symbolMask <<= 1;
		m_symbolMask |= 1;
	}
	m_dataBitCount = 0;
	m_lastSymbol = 0;
}

void DeSymbolizer::process(uint32_t src)
{
	uint32_t i, j;
	static uint8_t dst;
	static uint16_t preamble;
	uint16_t preamble_soll;
	uint32_t symSync;
	src = differentialDecode(src);
	symSync = src;
	const uint8_t preamble_bytes[2] = {(uint8_t)FRAME_PREAMBLE_IV, (uint8_t)(~FRAME_PREAMBLE_IV)};

	preamble_soll = ((uint16_t)preamble_bytes[0] << 8) | ((uint16_t)preamble_bytes[1] & 0xFF);

	j = 0;
	for (i=0; i < m_nBitsPerSym; i++)
	{
		preamble <<= 1;
		preamble |= (uint32_t)((symSync >> (m_nBitsPerSym-1) & 1) != 0);
		symSync <<= 1;
		if (preamble == preamble_soll)
		{
			// We have bit sync
			m_dataBitCount = 0;
			j = i + 1;
			src = symSync;
			preamble = 0;
			m_buf_out->write(preamble_bytes, sizeof(preamble_bytes));
		}
	}

	// Transmission order MSB first
	for (i=j; i < m_nBitsPerSym; i++)
	{
		dst <<= 1;
		dst |= (uint32_t)((src >> (m_nBitsPerSym-1) & 1) != 0);
		src <<= 1;
		m_dataBitCount++;
		if (m_dataBitCount == SIZEOF_DATA_BITS)
		{
			m_buf_out->write(&dst, 1);
			m_dataBitCount = 0;
			dst = 0;
		}
	}
}

void DeSymbolizer::prepare()
{
	// Get buffers
	m_buf_in = buffer_in<symbol_t>();
	m_buf_out = buffer_out<uint8_t>();
}

void DeSymbolizer::process()
{
	// Process input
	while(m_buf_in->len())
	{
		symbol_t sym;
		m_buf_in->read(&sym, 1);
		process(sym);
	}
}

uint32_t DeSymbolizer::differentialDecode(uint32_t symbol)
{
	uint32_t res;

	// Differential decode
	res = (uint32_t)(m_symbolMask & (symbol - m_lastSymbol));
	m_lastSymbol = symbol;

	return res;
}

// --------------------------------------------------------------