/******************************************************************************

 ** Filename:    ocrfeatures.cpp

 ** Purpose:     Generic definition of a feature.

 ** Author:      Dan Johnson

 **

 ** (c) Copyright Hewlett-Packard Company, 1988.

 ** Licensed under the Apache License, Version 2.0 (the "License");

 ** you may not use this file except in compliance with the License.

 ** You may obtain a copy of the License at

 ** http://www.apache.org/licenses/LICENSE-2.0

 ** Unless required by applicable law or agreed to in writing, software

 ** distributed under the License is distributed on an "AS IS" BASIS,

 ** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 ** See the License for the specific language governing permissions and

 ** limitations under the License.

 ******************************************************************************/

#include "ocrfeatures.h"

#include "scanutils.h"

#include <cassert>

#include <cmath>

#include <sstream> // for std::stringstream

namespace tesseract {

/*----------------------------------------------------------------------------

              Public Code

----------------------------------------------------------------------------*/

/**

 * Add a feature to a feature set.  If the feature set is

 * already full, false is returned to indicate that the

 * feature could not be added to the set; otherwise, true is

 * returned.

 * @param FeatureSet set of features to add Feature to

 * @param Feature feature to be added to FeatureSet

 * @return  true if feature added to set, false if set is already full.

 */

bool AddFeature(FEATURE_SET FeatureSet, FEATURE Feature) {

  if (FeatureSet->NumFeatures >= FeatureSet->MaxNumFeatures) {

    delete Feature;

    return false;

  }

  FeatureSet->Features[FeatureSet->NumFeatures++] = Feature;

  return true;

} /* AddFeature */

/**

 * Create a new feature of the specified type and read in

 * the value of its parameters from File.  The extra penalty

 * for the feature is also computed by calling the appropriate

 * function for the specified feature type.  The correct text

 * representation for a feature is a list of N floats where

 * N is the number of parameters in the feature.

 * @param File open text file to read feature from

 * @param FeatureDesc specifies type of feature to read from File

 * @return New #FEATURE read from File.

 */

static FEATURE ReadFeature(FILE *File, const FEATURE_DESC_STRUCT *FeatureDesc) {

  auto Feature = new FEATURE_STRUCT(FeatureDesc);

  for (int i = 0; i < Feature->Type->NumParams; i++) {

    ASSERT_HOST(tfscanf(File, "%f", &(Feature->Params[i])) == 1);

#ifndef _WIN32

    assert(!std::isnan(Feature->Params[i]));

#endif

  }

  return Feature;

}

/**

 * Create a new feature set of the specified type and read in

 * the features from File.  The correct text representation

 * for a feature set is an integer which specifies the number (N)

 * of features in a set followed by a list of N feature

 * descriptions.

 * @param File open text file to read new feature set from

 * @param FeatureDesc specifies type of feature to read from File

 * @return New feature set read from File.

 */

FEATURE_SET ReadFeatureSet(FILE *File, const FEATURE_DESC_STRUCT *FeatureDesc) {

  int NumFeatures;

  ASSERT_HOST(tfscanf(File, "%d", &NumFeatures) == 1);

  ASSERT_HOST(NumFeatures >= 0);

  auto FeatureSet = new FEATURE_SET_STRUCT(NumFeatures);

  for (int i = 0; i < NumFeatures; i++) {

    AddFeature(FeatureSet, ReadFeature(File, FeatureDesc));

  }

  return FeatureSet;

}

/**

 * Appends a textual representation of Feature to str.

 * This representation is simply a list of the N parameters

 * of the feature, terminated with a newline.  It is assumed

 * that the ExtraPenalty field can be reconstructed from the

 * parameters of the feature.  It is also assumed that the

 * feature type information is specified or assumed elsewhere.

 * @param Feature feature to write out to str

 * @param str string to write Feature to

 */

static void WriteFeature(FEATURE Feature, std::string &str) {

  for (int i = 0; i < Feature->Type->NumParams; i++) {

#ifndef WIN32

    assert(!std::isnan(Feature->Params[i]));

#endif

    std::stringstream stream;

    // Use "C" locale (needed for double value).

    stream.imbue(std::locale::classic());

    // Use 8 digits for double value.

    stream.precision(8);

    stream << Feature->Params[i];

    str += " " + stream.str();

  }

  str += "\n";

} /* WriteFeature */

/**

 * Write a textual representation of FeatureSet to File.

 * This representation is an integer specifying the number of

 * features in the set, followed by a newline, followed by

 * text representations for each feature in the set.

 * @param FeatureSet feature set to write to File

 * @param str string to write Feature to

 */

void WriteFeatureSet(FEATURE_SET FeatureSet, std::string &str) {

  if (FeatureSet) {

    str += "" + std::to_string(FeatureSet->NumFeatures);

    str += "\n";

    for (int i = 0; i < FeatureSet->NumFeatures; i++) {

      WriteFeature(FeatureSet->Features[i], str);

    }

  }

} /* WriteFeatureSet */

} // namespace tesseract