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Manchester decoder into separate class.

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Now operates directly on data, doesn't make a new pair of data/error bitsets.
This commit is contained in:
Jared Boone 2015-12-01 12:05:42 -08:00
parent 426295b93e
commit d75f601b54
1 changed files with 46 additions and 39 deletions
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85
firmware/application/ui_receiver.cpp
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@ -544,30 +544,60 @@ void ReceiverView::on_packet_ais(const AISPacketMessage& message) {
static FIL fil_tpms;
class ManchesterDecoder {
public:
struct DecodedSymbol {
bool value;
bool error;
};
constexpr ManchesterDecoder(
const std::bitset<1024>& encoded,
const size_t count,
const size_t sense = 0
) : encoded { encoded },
count { count },
sense { sense }
{
}
DecodedSymbol operator[](const size_t index) const {
const auto value = encoded[index * 2 + sense];
const auto error = encoded[index * 2 + 0] == encoded[index * 2 + 1];
return { value, error };
}
size_t symbols_count() const {
return count / 2;
}
private:
const std::bitset<1024>& encoded;
const size_t count;
const size_t sense;
};
static std::pair<std::string, std::string> format_manchester(
const uint_fast8_t sense,
const std::bitset<1024>& payload,
const size_t payload_length
const ManchesterDecoder& decoder
) {
const size_t payload_length_decoded = payload_length / 2;
const size_t payload_length_decoded = decoder.symbols_count();
const size_t payload_length_bytes = (payload_length_decoded + 7) / 8;
const size_t payload_length_symbols_rounded = payload_length_bytes * 8 * 2;
const size_t payload_length_symbols_rounded = payload_length_bytes * 8;
std::string hex_data;
std::string hex_error;
uint8_t byte_data = 0;
uint8_t byte_error = 0;
for(size_t i=0; i<payload_length_symbols_rounded; i+=2) {
const auto bit_data = payload[i+sense];
const auto bit_error = (payload[i+0] == payload[i+1]);
for(size_t i=0; i<payload_length_symbols_rounded; i++) {
const auto symbol = decoder[i];
byte_data <<= 1;
byte_data |= bit_data ? 1 : 0;
byte_data |= symbol.value ? 1 : 0;
byte_error <<= 1;
byte_error |= bit_error ? 1 : 0;
byte_error |= symbol.error ? 1 : 0;
if( ((i >> 1) & 7) == 7 ) {
if( (i & 7) == 7 ) {
hex_data += to_string_hex(byte_data, 2);
hex_error += to_string_hex(byte_error, 2);
}
@ -577,10 +607,8 @@ static std::pair<std::string, std::string> format_manchester(
}
void ReceiverView::on_packet_tpms(const TPMSPacketMessage& message) {
auto payload = message.packet.payload;
auto payload_length = message.packet.bits_received;
const auto hex_formatted = format_manchester(1, payload, payload_length);
const ManchesterDecoder decoder(message.packet.payload, message.packet.bits_received, 1);
const auto hex_formatted = format_manchester(decoder);
auto console = reinterpret_cast<Console*>(widget_content.get());
console->writeln(hex_formatted.first.substr(0, 240 / 8));
@ -606,29 +634,6 @@ void ReceiverView::on_packet_tpms(const TPMSPacketMessage& message) {
}
}
static std::bitset<512> manchester_decode(
const size_t sense,
const std::bitset<1024>& encoded,
const size_t count
) {
std::bitset<512> result;
for(size_t i=0; i<count; i+=2) {
result[i >> 1] = encoded[i+sense];
}
return result;
}
static std::bitset<512> manchester_errors(
const std::bitset<1024>& encoded,
const size_t count
) {
std::bitset<512> result;
for(size_t i=0; i<count; i+=2) {
result[i >> 1] = (encoded[i+0] == encoded[i+1]);
}
return result;
}
void ReceiverView::on_packet_ert(const ERTPacketMessage& message) {
auto console = reinterpret_cast<Console*>(widget_content.get());
@ -639,7 +644,9 @@ void ReceiverView::on_packet_ert(const ERTPacketMessage& message) {
console->writeln("SCM");
}
const auto hex_formatted = format_manchester(0, message.packet.payload, message.packet.bits_received);
const ManchesterDecoder decoder(message.packet.payload, message.packet.bits_received);
const auto hex_formatted = format_manchester(decoder);
console->writeln(hex_formatted.first);
console->writeln(hex_formatted.second);
}