Tasmota/lib/IRremoteESP8266-2.7.7/src/ir_Whirlpool.cpp
2020-05-20 12:42:34 +02:00

608 lines
20 KiB
C++

// Copyright 2018 David Conran
//
// Code to emulate Whirlpool protocol compatible devices.
// Should be compatible with:
// * SPIS409L, SPIS412L, SPIW409L, SPIW412L, SPIW418L
// Remotes:
// * DG11J1-3A / DG11J1-04
// * DG11J1-91
//
// Note: Smart, iFeel, AroundU, PowerSave, & Silent modes are unsupported.
// Advanced 6thSense, Dehumidify, & Sleep modes are not supported.
// FYI:
// Dim == !Light
// Jet == Super == Turbo
//
#include "ir_Whirlpool.h"
#include <algorithm>
#include <cstring>
#ifndef ARDUINO
#include <string>
#endif
#include "IRrecv.h"
#include "IRremoteESP8266.h"
#include "IRsend.h"
#include "IRtext.h"
#include "IRutils.h"
// Constants
// Ref: https://github.com/crankyoldgit/IRremoteESP8266/issues/509
const uint16_t kWhirlpoolAcHdrMark = 8950;
const uint16_t kWhirlpoolAcHdrSpace = 4484;
const uint16_t kWhirlpoolAcBitMark = 597;
const uint16_t kWhirlpoolAcOneSpace = 1649;
const uint16_t kWhirlpoolAcZeroSpace = 533;
const uint16_t kWhirlpoolAcGap = 7920;
const uint32_t kWhirlpoolAcMinGap = kDefaultMessageGap; // Just a guess.
const uint8_t kWhirlpoolAcSections = 3;
using irutils::addBoolToString;
using irutils::addFanToString;
using irutils::addIntToString;
using irutils::addLabeledString;
using irutils::addModeToString;
using irutils::addModelToString;
using irutils::addTempToString;
using irutils::minsToString;
using irutils::setBit;
using irutils::setBits;
#if SEND_WHIRLPOOL_AC
// Send a Whirlpool A/C message.
//
// Args:
// data: An array of bytes containing the IR command.
// nbytes: Nr. of bytes of data in the array. (>=kWhirlpoolAcStateLength)
// repeat: Nr. of times the message is to be repeated. (Default = 0).
//
// Status: BETA / Probably works.
//
// Ref:
// https://github.com/crankyoldgit/IRremoteESP8266/issues/509
void IRsend::sendWhirlpoolAC(const unsigned char data[], const uint16_t nbytes,
const uint16_t repeat) {
if (nbytes < kWhirlpoolAcStateLength)
return; // Not enough bytes to send a proper message.
for (uint16_t r = 0; r <= repeat; r++) {
// Section 1
sendGeneric(kWhirlpoolAcHdrMark, kWhirlpoolAcHdrSpace, kWhirlpoolAcBitMark,
kWhirlpoolAcOneSpace, kWhirlpoolAcBitMark,
kWhirlpoolAcZeroSpace, kWhirlpoolAcBitMark, kWhirlpoolAcGap,
data, 6, // 6 bytes == 48 bits
38000, // Complete guess of the modulation frequency.
false, 0, 50);
// Section 2
sendGeneric(0, 0, kWhirlpoolAcBitMark, kWhirlpoolAcOneSpace,
kWhirlpoolAcBitMark, kWhirlpoolAcZeroSpace, kWhirlpoolAcBitMark,
kWhirlpoolAcGap, data + 6, 8, // 8 bytes == 64 bits
38000, // Complete guess of the modulation frequency.
false, 0, 50);
// Section 3
sendGeneric(0, 0, kWhirlpoolAcBitMark, kWhirlpoolAcOneSpace,
kWhirlpoolAcBitMark, kWhirlpoolAcZeroSpace, kWhirlpoolAcBitMark,
kWhirlpoolAcMinGap, data + 14, 7, // 7 bytes == 56 bits
38000, // Complete guess of the modulation frequency.
false, 0, 50);
}
}
#endif // SEND_WHIRLPOOL_AC
// Class for emulating a Whirlpool A/C remote.
// Decoding help from:
// @redmusicxd, @josh929800, @raducostea
IRWhirlpoolAc::IRWhirlpoolAc(const uint16_t pin, const bool inverted,
const bool use_modulation)
: _irsend(pin, inverted, use_modulation) { this->stateReset(); }
void IRWhirlpoolAc::stateReset(void) {
for (uint8_t i = 2; i < kWhirlpoolAcStateLength; i++) remote_state[i] = 0x0;
remote_state[0] = 0x83;
remote_state[1] = 0x06;
remote_state[6] = 0x80;
this->_setTemp(kWhirlpoolAcAutoTemp); // Default to a sane value.
}
void IRWhirlpoolAc::begin(void) { _irsend.begin(); }
bool IRWhirlpoolAc::validChecksum(uint8_t state[], const uint16_t length) {
if (length > kWhirlpoolAcChecksumByte1 &&
state[kWhirlpoolAcChecksumByte1] !=
xorBytes(state + 2, kWhirlpoolAcChecksumByte1 - 1 - 2)) {
DPRINTLN("DEBUG: First Whirlpool AC checksum failed.");
return false;
}
if (length > kWhirlpoolAcChecksumByte2 &&
state[kWhirlpoolAcChecksumByte2] !=
xorBytes(state + kWhirlpoolAcChecksumByte1 + 1,
kWhirlpoolAcChecksumByte2 - kWhirlpoolAcChecksumByte1 - 1)) {
DPRINTLN("DEBUG: Second Whirlpool AC checksum failed.");
return false;
}
// State is too short to have a checksum or everything checked out.
return true;
}
// Update the checksum for the internal state.
void IRWhirlpoolAc::checksum(uint16_t length) {
if (length >= kWhirlpoolAcChecksumByte1)
remote_state[kWhirlpoolAcChecksumByte1] =
xorBytes(remote_state + 2, kWhirlpoolAcChecksumByte1 - 1 - 2);
if (length >= kWhirlpoolAcChecksumByte2)
remote_state[kWhirlpoolAcChecksumByte2] =
xorBytes(remote_state + kWhirlpoolAcChecksumByte1 + 1,
kWhirlpoolAcChecksumByte2 - kWhirlpoolAcChecksumByte1 - 1);
}
#if SEND_WHIRLPOOL_AC
void IRWhirlpoolAc::send(const uint16_t repeat, const bool calcchecksum) {
if (calcchecksum) this->checksum();
_irsend.sendWhirlpoolAC(remote_state, kWhirlpoolAcStateLength, repeat);
}
#endif // SEND_WHIRLPOOL_AC
uint8_t *IRWhirlpoolAc::getRaw(const bool calcchecksum) {
if (calcchecksum) this->checksum();
return remote_state;
}
void IRWhirlpoolAc::setRaw(const uint8_t new_code[], const uint16_t length) {
memcpy(remote_state, new_code, std::min(length, kWhirlpoolAcStateLength));
}
whirlpool_ac_remote_model_t IRWhirlpoolAc::getModel(void) {
if (GETBIT8(remote_state[kWhirlpoolAcAltTempPos], kWhirlpoolAcAltTempOffset))
return DG11J191;
else
return DG11J13A;
}
void IRWhirlpoolAc::setModel(const whirlpool_ac_remote_model_t model) {
switch (model) {
case DG11J191:
setBit(&remote_state[kWhirlpoolAcAltTempPos], kWhirlpoolAcAltTempOffset);
break;
case DG11J13A:
// FALL THRU
default:
setBit(&remote_state[kWhirlpoolAcAltTempPos], kWhirlpoolAcAltTempOffset,
false);
}
this->_setTemp(_desiredtemp); // Different models have different temp values.
}
// Return the temp. offset in deg C for the current model.
int8_t IRWhirlpoolAc::getTempOffset(void) {
switch (this->getModel()) {
case whirlpool_ac_remote_model_t::DG11J191: return -2;
default: return 0;
}
}
// Set the temp. in deg C
void IRWhirlpoolAc::_setTemp(const uint8_t temp, const bool remember) {
if (remember) _desiredtemp = temp;
int8_t offset = this->getTempOffset(); // Cache the min temp for the model.
uint8_t newtemp = std::max((uint8_t)(kWhirlpoolAcMinTemp + offset), temp);
newtemp = std::min((uint8_t)(kWhirlpoolAcMaxTemp + offset), newtemp);
setBits(&remote_state[kWhirlpoolAcTempPos], kHighNibble, kNibbleSize,
newtemp - (kWhirlpoolAcMinTemp + offset));
}
// Set the temp. in deg C
void IRWhirlpoolAc::setTemp(const uint8_t temp) {
this->_setTemp(temp);
this->setSuper(false); // Changing temp cancels Super/Jet mode.
this->setCommand(kWhirlpoolAcCommandTemp);
}
// Return the set temp. in deg C
uint8_t IRWhirlpoolAc::getTemp(void) {
return GETBITS8(remote_state[kWhirlpoolAcTempPos], kHighNibble, kNibbleSize) +
kWhirlpoolAcMinTemp + this->getTempOffset();
}
void IRWhirlpoolAc::_setMode(const uint8_t mode) {
switch (mode) {
case kWhirlpoolAcAuto:
this->setFan(kWhirlpoolAcFanAuto);
this->_setTemp(kWhirlpoolAcAutoTemp, false);
this->setSleep(false); // Cancel sleep mode when in auto/6thsense mode.
// FALL THRU
case kWhirlpoolAcHeat:
case kWhirlpoolAcCool:
case kWhirlpoolAcDry:
case kWhirlpoolAcFan:
setBits(&remote_state[kWhirlpoolAcModePos], kWhirlpoolAcModeOffset,
kModeBitsSize, mode);
this->setCommand(kWhirlpoolAcCommandMode);
break;
default:
return;
}
if (mode == kWhirlpoolAcAuto) this->setCommand(kWhirlpoolAcCommand6thSense);
}
void IRWhirlpoolAc::setMode(const uint8_t mode) {
this->setSuper(false); // Changing mode cancels Super/Jet mode.
this->_setMode(mode);
}
uint8_t IRWhirlpoolAc::getMode(void) {
return GETBITS8(remote_state[kWhirlpoolAcModePos], kWhirlpoolAcModeOffset,
kModeBitsSize);
}
void IRWhirlpoolAc::setFan(const uint8_t speed) {
switch (speed) {
case kWhirlpoolAcFanAuto:
case kWhirlpoolAcFanLow:
case kWhirlpoolAcFanMedium:
case kWhirlpoolAcFanHigh:
setBits(&remote_state[kWhirlpoolAcFanPos], kWhirlpoolAcFanOffset,
kWhirlpoolAcFanSize, speed);
this->setSuper(false); // Changing fan speed cancels Super/Jet mode.
this->setCommand(kWhirlpoolAcCommandFanSpeed);
break;
}
}
uint8_t IRWhirlpoolAc::getFan(void) {
return GETBITS8(remote_state[kWhirlpoolAcFanPos], kWhirlpoolAcFanOffset,
kWhirlpoolAcFanSize);
}
void IRWhirlpoolAc::setSwing(const bool on) {
setBit(&remote_state[kWhirlpoolAcFanPos], kWhirlpoolAcSwing1Offset, on);
setBit(&remote_state[kWhirlpoolAcOffTimerPos], kWhirlpoolAcSwing2Offset, on);
setCommand(kWhirlpoolAcCommandSwing);
}
bool IRWhirlpoolAc::getSwing(void) {
return GETBIT8(remote_state[kWhirlpoolAcFanPos], kWhirlpoolAcSwing1Offset) &&
GETBIT8(remote_state[kWhirlpoolAcOffTimerPos],
kWhirlpoolAcSwing2Offset);
}
void IRWhirlpoolAc::setLight(const bool on) {
// Cleared when on.
setBit(&remote_state[kWhirlpoolAcClockPos], kWhirlpoolAcLightOffset, !on);
}
bool IRWhirlpoolAc::getLight(void) {
return !GETBIT8(remote_state[kWhirlpoolAcClockPos], kWhirlpoolAcLightOffset);
}
void IRWhirlpoolAc::setTime(const uint16_t pos,
const uint16_t minspastmidnight) {
// Hours
setBits(&remote_state[pos], kWhirlpoolAcHourOffset, kWhirlpoolAcHourSize,
(minspastmidnight / 60) % 24);
// Minutes
setBits(&remote_state[pos + 1], kWhirlpoolAcMinuteOffset,
kWhirlpoolAcMinuteSize, minspastmidnight % 60);
}
uint16_t IRWhirlpoolAc::getTime(const uint16_t pos) {
return GETBITS8(remote_state[pos], kWhirlpoolAcHourOffset,
kWhirlpoolAcHourSize) * 60 +
GETBITS8(remote_state[pos + 1], kWhirlpoolAcMinuteOffset,
kWhirlpoolAcMinuteSize);
}
bool IRWhirlpoolAc::isTimerEnabled(const uint16_t pos) {
return GETBIT8(remote_state[pos - 1], kWhirlpoolAcTimerEnableOffset);
}
void IRWhirlpoolAc::enableTimer(const uint16_t pos, const bool on) {
setBit(&remote_state[pos - 1], kWhirlpoolAcTimerEnableOffset, on);
}
void IRWhirlpoolAc::setClock(const uint16_t minspastmidnight) {
this->setTime(kWhirlpoolAcClockPos, minspastmidnight);
}
uint16_t IRWhirlpoolAc::getClock(void) {
return this->getTime(kWhirlpoolAcClockPos);
}
void IRWhirlpoolAc::setOffTimer(const uint16_t minspastmidnight) {
this->setTime(kWhirlpoolAcOffTimerPos, minspastmidnight);
}
uint16_t IRWhirlpoolAc::getOffTimer(void) {
return this->getTime(kWhirlpoolAcOffTimerPos);
}
bool IRWhirlpoolAc::isOffTimerEnabled(void) {
return this->isTimerEnabled(kWhirlpoolAcOffTimerPos);
}
void IRWhirlpoolAc::enableOffTimer(const bool on) {
this->enableTimer(kWhirlpoolAcOffTimerPos, on);
this->setCommand(kWhirlpoolAcCommandOffTimer);
}
void IRWhirlpoolAc::setOnTimer(const uint16_t minspastmidnight) {
this->setTime(kWhirlpoolAcOnTimerPos, minspastmidnight);
}
uint16_t IRWhirlpoolAc::getOnTimer(void) {
return this->getTime(kWhirlpoolAcOnTimerPos);
}
bool IRWhirlpoolAc::isOnTimerEnabled(void) {
return this->isTimerEnabled(kWhirlpoolAcOnTimerPos);
}
void IRWhirlpoolAc::enableOnTimer(const bool on) {
this->enableTimer(kWhirlpoolAcOnTimerPos, on);
this->setCommand(kWhirlpoolAcCommandOnTimer);
}
void IRWhirlpoolAc::setPowerToggle(const bool on) {
setBit(&remote_state[kWhirlpoolAcPowerTogglePos],
kWhirlpoolAcPowerToggleOffset, on);
this->setSuper(false); // Changing power cancels Super/Jet mode.
this->setCommand(kWhirlpoolAcCommandPower);
}
bool IRWhirlpoolAc::getPowerToggle(void) {
return GETBIT8(remote_state[kWhirlpoolAcPowerTogglePos],
kWhirlpoolAcPowerToggleOffset);
}
uint8_t IRWhirlpoolAc::getCommand(void) {
return remote_state[kWhirlpoolAcCommandPos];
}
void IRWhirlpoolAc::setSleep(const bool on) {
setBit(&remote_state[kWhirlpoolAcSleepPos],
kWhirlpoolAcSleepOffset, on);
if (on) this->setFan(kWhirlpoolAcFanLow);
this->setCommand(kWhirlpoolAcCommandSleep);
}
bool IRWhirlpoolAc::getSleep(void) {
return GETBIT8(remote_state[kWhirlpoolAcSleepPos], kWhirlpoolAcSleepOffset);
}
// AKA Jet/Turbo mode.
void IRWhirlpoolAc::setSuper(const bool on) {
if (on) {
this->setFan(kWhirlpoolAcFanHigh);
switch (this->getMode()) {
case kWhirlpoolAcHeat:
this->setTemp(kWhirlpoolAcMaxTemp + this->getTempOffset());
break;
case kWhirlpoolAcCool:
default:
this->setTemp(kWhirlpoolAcMinTemp + this->getTempOffset());
this->setMode(kWhirlpoolAcCool);
break;
}
remote_state[kWhirlpoolAcSuperPos] |= kWhirlpoolAcSuperMask;
} else {
remote_state[kWhirlpoolAcSuperPos] &= ~kWhirlpoolAcSuperMask;
}
this->setCommand(kWhirlpoolAcCommandSuper);
}
bool IRWhirlpoolAc::getSuper(void) {
return remote_state[kWhirlpoolAcSuperPos] & kWhirlpoolAcSuperMask;
}
void IRWhirlpoolAc::setCommand(const uint8_t code) {
remote_state[kWhirlpoolAcCommandPos] = code;
}
// Convert a standard A/C mode into its native mode.
uint8_t IRWhirlpoolAc::convertMode(const stdAc::opmode_t mode) {
switch (mode) {
case stdAc::opmode_t::kCool: return kWhirlpoolAcCool;
case stdAc::opmode_t::kHeat: return kWhirlpoolAcHeat;
case stdAc::opmode_t::kDry: return kWhirlpoolAcDry;
case stdAc::opmode_t::kFan: return kWhirlpoolAcFan;
default: return kWhirlpoolAcAuto;
}
}
// Convert a standard A/C Fan speed into its native fan speed.
uint8_t IRWhirlpoolAc::convertFan(const stdAc::fanspeed_t speed) {
switch (speed) {
case stdAc::fanspeed_t::kMin:
case stdAc::fanspeed_t::kLow: return kWhirlpoolAcFanLow;
case stdAc::fanspeed_t::kMedium: return kWhirlpoolAcFanMedium;
case stdAc::fanspeed_t::kHigh:
case stdAc::fanspeed_t::kMax: return kWhirlpoolAcFanHigh;
default: return kWhirlpoolAcFanAuto;
}
}
// Convert a native mode to it's common equivalent.
stdAc::opmode_t IRWhirlpoolAc::toCommonMode(const uint8_t mode) {
switch (mode) {
case kWhirlpoolAcCool: return stdAc::opmode_t::kCool;
case kWhirlpoolAcHeat: return stdAc::opmode_t::kHeat;
case kWhirlpoolAcDry: return stdAc::opmode_t::kDry;
case kWhirlpoolAcFan: return stdAc::opmode_t::kFan;
default: return stdAc::opmode_t::kAuto;
}
}
// Convert a native fan speed to it's common equivalent.
stdAc::fanspeed_t IRWhirlpoolAc::toCommonFanSpeed(const uint8_t speed) {
switch (speed) {
case kWhirlpoolAcFanHigh: return stdAc::fanspeed_t::kMax;
case kWhirlpoolAcFanMedium: return stdAc::fanspeed_t::kMedium;
case kWhirlpoolAcFanLow: return stdAc::fanspeed_t::kMin;
default: return stdAc::fanspeed_t::kAuto;
}
}
// Convert the A/C state to it's common equivalent.
stdAc::state_t IRWhirlpoolAc::toCommon(void) {
stdAc::state_t result;
result.protocol = decode_type_t::WHIRLPOOL_AC;
result.model = this->getModel();
result.power = this->getPowerToggle();
result.mode = this->toCommonMode(this->getMode());
result.celsius = true;
result.degrees = this->getTemp();
result.fanspeed = this->toCommonFanSpeed(this->getFan());
result.swingv = this->getSwing() ? stdAc::swingv_t::kAuto :
stdAc::swingv_t::kOff;
result.turbo = this->getSuper();
result.light = this->getLight();
result.sleep = this->getSleep() ? 0 : -1;
// Not supported.
result.swingh = stdAc::swingh_t::kOff;
result.quiet = false;
result.filter = false;
result.econo = false;
result.clean = false;
result.beep = false;
result.clock = -1;
return result;
}
// Convert the internal state into a human readable string.
String IRWhirlpoolAc::toString(void) {
String result = "";
result.reserve(200); // Reserve some heap for the string to reduce fragging.
result += addModelToString(decode_type_t::WHIRLPOOL_AC, getModel(), false);
result += addBoolToString(getPowerToggle(), kPowerToggleStr);
result += addModeToString(getMode(), kWhirlpoolAcAuto, kWhirlpoolAcCool,
kWhirlpoolAcHeat, kWhirlpoolAcDry, kWhirlpoolAcFan);
result += addTempToString(getTemp());
result += addFanToString(getFan(), kWhirlpoolAcFanHigh, kWhirlpoolAcFanLow,
kWhirlpoolAcFanAuto, kWhirlpoolAcFanAuto,
kWhirlpoolAcFanMedium);
result += addBoolToString(getSwing(), kSwingStr);
result += addBoolToString(getLight(), kLightStr);
result += addLabeledString(minsToString(getClock()), kClockStr);
result += addLabeledString(
isOnTimerEnabled() ? minsToString(getOnTimer()) : kOffStr,
kOnTimerStr);
result += addLabeledString(
isOffTimerEnabled() ? minsToString(getOffTimer()) : kOffStr,
kOffTimerStr);
result += addBoolToString(getSleep(), kSleepStr);
result += addBoolToString(getSuper(), kSuperStr);
result += addIntToString(getCommand(), kCommandStr);
result += kSpaceLBraceStr;
switch (this->getCommand()) {
case kWhirlpoolAcCommandLight:
result += kLightStr;
break;
case kWhirlpoolAcCommandPower:
result += kPowerStr;
break;
case kWhirlpoolAcCommandTemp:
result += kTempStr;
break;
case kWhirlpoolAcCommandSleep:
result += kSleepStr;
break;
case kWhirlpoolAcCommandSuper:
result += kSuperStr;
break;
case kWhirlpoolAcCommandOnTimer:
result += kOnTimerStr;
break;
case kWhirlpoolAcCommandMode:
result += kModeStr;
break;
case kWhirlpoolAcCommandSwing:
result += kSwingStr;
break;
case kWhirlpoolAcCommandIFeel:
result += kIFeelStr;
break;
case kWhirlpoolAcCommandFanSpeed:
result += kFanStr;
break;
case kWhirlpoolAcCommand6thSense:
result += k6thSenseStr;
break;
case kWhirlpoolAcCommandOffTimer:
result += kOffTimerStr;
break;
default:
result += kUnknownStr;
break;
}
result += ')';
return result;
}
#if DECODE_WHIRLPOOL_AC
// Decode the supplied Whirlpool A/C message.
//
// Args:
// results: Ptr to the data to decode and where to store the decode result.
// offset: The starting index to use when attempting to decode the raw data.
// Typically/Defaults to kStartOffset.
// nbits: The number of data bits to expect. Typically kWhirlpoolAcBits
// strict: Flag indicating if we should perform strict matching.
// Returns:
// boolean: True if it can decode it, false if it can't.
//
// Status: STABLE / Working as intended.
//
//
// Ref:
// https://github.com/crankyoldgit/IRremoteESP8266/issues/509
bool IRrecv::decodeWhirlpoolAC(decode_results *results, uint16_t offset,
const uint16_t nbits, const bool strict) {
if (results->rawlen < 2 * nbits + 4 + kHeader + kFooter - 1 + offset)
return false; // Can't possibly be a valid Whirlpool A/C message.
if (strict) {
if (nbits != kWhirlpoolAcBits) return false;
}
const uint8_t sectionSize[kWhirlpoolAcSections] = {6, 8, 7};
// Header
if (!matchMark(results->rawbuf[offset++], kWhirlpoolAcHdrMark)) return false;
if (!matchSpace(results->rawbuf[offset++], kWhirlpoolAcHdrSpace))
return false;
// Data Sections
uint16_t pos = 0;
for (uint8_t section = 0; section < kWhirlpoolAcSections;
section++) {
uint16_t used;
// Section Data
used = matchGeneric(results->rawbuf + offset, results->state + pos,
results->rawlen - offset, sectionSize[section] * 8,
0, 0,
kWhirlpoolAcBitMark, kWhirlpoolAcOneSpace,
kWhirlpoolAcBitMark, kWhirlpoolAcZeroSpace,
kWhirlpoolAcBitMark, kWhirlpoolAcGap,
section >= kWhirlpoolAcSections - 1,
_tolerance, kMarkExcess, false);
if (used == 0) return false;
offset += used;
pos += sectionSize[section];
}
// Compliance
if (strict) {
// Re-check we got the correct size/length due to the way we read the data.
if (pos * 8 != nbits) return false;
if (!IRWhirlpoolAc::validChecksum(results->state, nbits / 8))
return false;
}
// Success
results->decode_type = WHIRLPOOL_AC;
results->bits = nbits;
// No need to record the state as we stored it as we decoded it.
// As we use result->state, we don't record value, address, or command as it
// is a union data type.
return true;
}
#endif // WHIRLPOOL_AC