Upsilon/apps/shared/cartesian_function.cpp

#include "cartesian_function.h"
#include "expression_model_store.h"
#include "poincare_helpers.h"
#include <poincare/derivative.h>
#include <poincare/serialization_helper.h>
#include <escher/palette.h>
#include <ion/unicode/utf8_decoder.h>
#include <float.h>
#include <cmath>

using namespace Poincare;

namespace Shared {

void CartesianFunction::DefaultName(char buffer[], size_t bufferSize) {
  constexpr int k_maxNumberOfDefaultLetterNames = 4;
  static constexpr const char k_defaultLetterNames[k_maxNumberOfDefaultLetterNames] = {
    'f', 'g', 'h', 'p'
  };
  /* First default names are f, g, h, p and then f0, f1... ie, "f[number]",
   * for instance "f12", that does not exist yet in the storage. */
  size_t constantNameLength = 1; // 'f', no null-terminating char
  assert(bufferSize > constantNameLength+1);
  // Find the next available name
  int currentNumber = -k_maxNumberOfDefaultLetterNames;
  int currentNumberLength = 0;
  int availableBufferSize = bufferSize - constantNameLength;
  while (currentNumberLength < availableBufferSize) {
    // Choose letter
    buffer[0] = currentNumber < 0 ? k_defaultLetterNames[k_maxNumberOfDefaultLetterNames+currentNumber] : k_defaultLetterNames[0];
    // Choose number if required
    if (currentNumber >= 0) {
      currentNumberLength = Poincare::Integer(currentNumber).serialize(&buffer[1], availableBufferSize);
    } else {
      buffer[1] = 0;
    }
    if (GlobalContext::SymbolAbstractNameIsFree(buffer)) {
      // Name found
      break;
    }
    currentNumber++;
  }
  assert(currentNumberLength >= 0 && currentNumberLength < availableBufferSize);
}

CartesianFunction CartesianFunction::NewModel(Ion::Storage::Record::ErrorStatus * error, const char * baseName) {
  static int s_colorIndex = 0;
  // Create the record
  char nameBuffer[SymbolAbstract::k_maxNameSize];
  int numberOfColors = sizeof(Palette::DataColor)/sizeof(KDColor);
  CartesianFunctionRecordDataBuffer data(Palette::DataColor[s_colorIndex++ % numberOfColors]);
  if (baseName == nullptr) {
    DefaultName(nameBuffer, SymbolAbstract::k_maxNameSize);
    baseName = nameBuffer;
  }
  *error = Ion::Storage::sharedStorage()->createRecordWithExtension(baseName, Ion::Storage::funcExtension, &data, sizeof(data));

  // Return if error
  if (*error != Ion::Storage::Record::ErrorStatus::None) {
    return CartesianFunction();
  }

  // Return the CartesianFunction withthe new record
  return CartesianFunction(Ion::Storage::sharedStorage()->recordBaseNamedWithExtension(baseName, Ion::Storage::funcExtension));
}

int CartesianFunction::derivativeNameWithArgument(char * buffer, size_t bufferSize) {
  // Fill buffer with f(x). Keep size for derivative sign.
  int derivativeSize = UTF8Decoder::CharSizeOfCodePoint('\'');
  int numberOfChars = nameWithArgument(buffer, bufferSize - derivativeSize);
  assert(numberOfChars + derivativeSize < (int)bufferSize);
  char * firstParenthesis = const_cast<char *>(UTF8Helper::CodePointSearch(buffer, '('));
  if (!UTF8Helper::CodePointIs(firstParenthesis, '(')) {
    return numberOfChars;
  }
  memmove(firstParenthesis + derivativeSize, firstParenthesis, numberOfChars - (firstParenthesis - buffer) + 1);
  UTF8Decoder::CodePointToChars('\'', firstParenthesis, derivativeSize);
  return numberOfChars + derivativeSize;
}

Poincare::Expression CartesianFunction::expressionReduced(Poincare::Context * context) const {
  Poincare::Expression result = ExpressionModelHandle::expressionReduced(context);
  if (plotType() == PlotType::Parametric && (
      result.type() != Poincare::ExpressionNode::Type::Matrix ||
      static_cast<Poincare::Matrix&>(result).numberOfRows() != 2 ||
      static_cast<Poincare::Matrix&>(result).numberOfColumns() != 1)
     ) {
    return Poincare::Expression::Parse("[[undef][undef]]");
  }
  return result;
}

CodePoint CartesianFunction::symbol() const {
  switch (plotType()) {
  case PlotType::Cartesian:
    return 'x';
  case PlotType::Polar:
    return UCodePointGreekSmallLetterTheta;
  default:
    assert(plotType() == PlotType::Parametric);
    return 't';
  }
}

CartesianFunction::PlotType CartesianFunction::plotType() const {
  return recordData()->plotType();
}

void CartesianFunction::setPlotType(PlotType plotType) {
  /* Reset memoized layout. */
  m_model.tidy();
  return recordData()->setPlotType(plotType);
}

Coordinate2D<double> CartesianFunction::evaluateXYAtParameter(double t, Poincare::Context * context) const {
  Coordinate2D<double> x1x2 = evaluate2DAtParameter(t, context);
  PlotType type = plotType();
  if (type == PlotType::Cartesian || type == PlotType::Parametric) {
    return x1x2;
  }
  assert(type == PlotType::Polar);
  return Coordinate2D<double>(x1x2.y() * std::cos(x1x2.x()*3.14/180.0), x1x2.y() * std::sin(x1x2.x()*3.14/180.0)); //TODO LEA RUBEN
}

bool CartesianFunction::displayDerivative() const {
  return recordData()->displayDerivative();
}

void CartesianFunction::setDisplayDerivative(bool display) {
  return recordData()->setDisplayDerivative(display);
}

double CartesianFunction::approximateDerivative(double x, Poincare::Context * context) const {
  Poincare::Derivative derivative = Poincare::Derivative::Builder(expressionReduced(context).clone(), Symbol::Builder(UCodePointUnknownX), Poincare::Float<double>::Builder(x)); // derivative takes ownership of Poincare::Float<double>::Builder(x) and the clone of expression
  /* TODO: when we approximate derivative, we might want to simplify the
   * derivative here. However, we might want to do it once for all x (to avoid
   * lagging in the derivative table. */
  return PoincareHelpers::ApproximateToScalar<double>(derivative, context);
}

double CartesianFunction::tMin() const {
  return recordData()->tMin();
}

double CartesianFunction::tMax() const {
  return recordData()->tMax();
}

void CartesianFunction::setTMin(double tMin) {
  recordData()->setTMin(tMin);
}

void CartesianFunction::setTMax(double tMax) {
  recordData()->setTMax(tMax);
}

void * CartesianFunction::Model::expressionAddress(const Ion::Storage::Record * record) const {
  return (char *)record->value().buffer+sizeof(CartesianFunctionRecordDataBuffer);
}

size_t CartesianFunction::Model::expressionSize(const Ion::Storage::Record * record) const {
  return record->value().size-sizeof(CartesianFunctionRecordDataBuffer);
}

CartesianFunction::CartesianFunctionRecordDataBuffer * CartesianFunction::recordData() const {
  assert(!isNull());
  Ion::Storage::Record::Data d = value();
  return reinterpret_cast<CartesianFunctionRecordDataBuffer *>(const_cast<void *>(d.buffer));
}

template<typename T>
Coordinate2D<T> CartesianFunction::templatedApproximateAtParameter(T t, Poincare::Context * context) const {
  if (isCircularlyDefined(context)) {
    return Coordinate2D<T>(NAN, NAN);
  }
  constexpr int bufferSize = CodePoint::MaxCodePointCharLength + 1;
  char unknown[bufferSize];
  Poincare::SerializationHelper::CodePoint(unknown, bufferSize, symbol());
  PlotType type = plotType();
  if (type == PlotType::Cartesian || type == PlotType::Polar) {
    return Coordinate2D<T>(t, PoincareHelpers::ApproximateWithValueForSymbol(expressionReduced(context), unknown, t, context));
  }
  assert(type == PlotType::Parametric);
  Expression e = expressionReduced(context);
  assert(e.type() == ExpressionNode::Type::Matrix);
  assert(static_cast<Poincare::Matrix&>(e).numberOfRows() == 2);
  assert(static_cast<Poincare::Matrix&>(e).numberOfColumns() == 1);
  return Coordinate2D<T>(
      PoincareHelpers::ApproximateWithValueForSymbol(e.childAtIndex(0), unknown, t, context),
      PoincareHelpers::ApproximateWithValueForSymbol(e.childAtIndex(1), unknown, t, context));
}

template Coordinate2D<float> CartesianFunction::templatedApproximateAtParameter<float>(float, Poincare::Context *) const;
template Coordinate2D<double> CartesianFunction::templatedApproximateAtParameter<double>(double, Poincare::Context *) const;

}