VirtualWireCodec.cpp

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#include "VirtualWireCodec.hh"

const uint8_t VirtualWireCodec::s_symbols[] __PROGMEM = {
  0xd,  0xe,  0x13, 0x15, 0x16, 0x19, 0x1a, 0x1c,
  0x23, 0x25, 0x26, 0x29, 0x2a, 0x2c, 0x32, 0x34
};

/*
 * Calculating the start symbol (6-bits per symbol):
 * 0x2a, 0x2a => 10.1010, 10.1010 (preamble 6-bit).
 * 0x38, 0x2c => 10.1100, 11.1000 => 1011,0011.1000 => 0xb38
 */
const uint8_t VirtualWireCodec::s_preamble[] __PROGMEM = {
  0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x2a, 0x38, 0x2c
};

uint8_t
VirtualWireCodec::decode4(uint8_t symbol)
{
  symbol &= SYMBOL_MASK;
  // FIX: Binary search for better speed
  for (uint8_t i = 0; i < membersof(s_symbols); i++)
    if (symbol == pgm_read_byte(&s_symbols[i]))
      return (i);
  return (0);
}