FitsToJson.cpp

 
/* SPDX-License-Identifier: CC0-1.0 */
#include "FitsToJson.h"
 
#include <nlohmann/json.hpp>
#include <QString>
 
#include "IException.h"
#include "IString.h"
#include "PvlObject.h"
#include "PvlGroup.h"
#include "PvlToJSON.h"
 
using json = nlohmann::json;
 
namespace Isis {
 
  json fitsToJson(std::ifstream &fileStream) {
    PvlObject fitsPvl;
    QList<PvlGroup *> *fitsImageLabels = new QList< PvlGroup * >;
    QList<PvlGroup *> *extraFitsLabels = new QList< PvlGroup * >;
    QList<int> *headerSizes = new QList < int >;
    QList<int> *dataStarts = new QList < int >;
 
    // Process each FITS label area, storing each in its own PvlGroup.
    char readBuf[81];
    IString line = "";
    unsigned int place;
 
    // Start at the beginning of the file for the main FITS label
    fileStream.seekg(0, std::ios_base::beg);
 
    // Reads each label line (80 chars)
    while (fileStream.read(readBuf, 80) && fileStream.gcount() == 80) {
 
      PvlGroup *fitsLabel = new PvlGroup("FitsLabels");
 
      readBuf[80] = '\0';
      line = readBuf;
      place = 80;
 
      // Process each fits label record (80 bytes) and place keyword, value pairs into PvlKeywords
      // with any associated comments.
      while (line.substr(0, 3) != "END") {
 
        // Check for blank lines
        if (line.substr(0, 1) != " " && line.substr(0, 1) != "/") {
          // Name of keyword
          PvlKeyword label(line.Token(" =").ToQt()); // Stop on spaces OR equal sign
          if (QString::compare(label.name(), "OBJECT", Qt::CaseInsensitive) == 0) {
            label.setName("TARGET");
            label.addComment("NOTE: This keyword name was changed from 'OBJECT' in the original "
                             "fit header file.");
          }
          // Remove up to beginning of data
          line.TrimHead(" =");
          line.TrimTail(" ");
          if (label.name() == "COMMENT" || label.name() == "HISTORY") {
            label += line.ToQt();
          }
          else {
            // Check for a quoted value
            if (line.substr(0,1) == "'") {
              line.TrimHead("'");
              label += line.Token("'").TrimHead(" ").TrimTail(" ").ToQt();
              line.TrimHead(" '");
            }
            else {
              // Access any remaining data without the trailing comment if there is one
              IString value = line.Token("/");
              value.TrimTail(" ");
              label += value.ToQt();
              line.TrimHead(" ");
            }
            // If the line still has anything in it, treat it is as a comment.
            if (line.size() > 0) {
              line.TrimHead(" /");
              label.addComment(line.ToQt());
              if (line != line.Token("[")) {
                label.setUnits(line.Token("[").Token("]").ToQt());
              }
            }
          }
          fitsLabel->addKeyword(label);
        }
 
        fileStream.read(readBuf, 80);
        readBuf[80] = '\0';
        line = readBuf;
        place += 80;
      }
      fitsPvl.addGroup(*fitsLabel);
      // Move the file pointer past the padding after the "END" (i.e., points to start of data)
      std::streamoff jump;
      jump = headerSizes->last() * 2880 - place;
      fileStream.seekg(jump, std::ios_base::cur);
 
      dataStarts->append(fileStream.tellg());
 
      if (fitsLabel->hasKeyword("BITPIX") && fitsLabel->hasKeyword("NAXIS")) {
 
        if((int)fitsLabel->findKeyword("NAXIS") > 0) {
          int bytesPerPixel = 0;
          bytesPerPixel = (int)((*fitsLabel)["BITPIX"]);
          bytesPerPixel = std::abs(bytesPerPixel);
          bytesPerPixel /= 8;
 
          unsigned int axis1 = 1;
          axis1 = toInt((*fitsLabel)["NAXIS1"]);
 
          unsigned int axis2 = 1;
          if (fitsLabel->hasKeyword("NAXIS2")) {
            axis2 = toInt((*fitsLabel)["NAXIS2"]);
          }
 
          unsigned int axis3 = 1;
          if (fitsLabel->hasKeyword("NAXIS3")) {
            axis3 = toInt((*fitsLabel)["NAXIS3"]);
          }
 
          jump = (int)(ceil(bytesPerPixel * axis1 * axis2 * axis3 / 2880.0) * 2880.0);
          fileStream.seekg(jump, std::ios_base::cur);
        }
        else {
          // Note: this will allow us to read extra label sections that have 0 axes,
          // but has image-related info (so BITPIX and NAXIS keywords exist). This
          // includes informational labels, as seen at the beginning of hayabusa2
          // images in this case, there is NO DATA, so no jump should be needed to
          // get to the next section.
          PvlGroup *extraLabelGroup = fitsImageLabels->last();
          extraLabelGroup->setName("FitsExtras");
          extraFitsLabels->append(extraLabelGroup);
 
          fitsImageLabels->removeLast();
          headerSizes->removeLast();
          dataStarts->removeLast();
 
          fitsPvl.addGroup(*extraLabelGroup);
        }
      }
      else if (fitsImageLabels->size() > 1) {
        fitsImageLabels->removeLast();
        headerSizes->removeLast();
        dataStarts->removeLast();
        break;
      }
 
      else {
        QString msg = QObject::tr("The FITS file does not contain a section header that appears "
                                  "to describe an image.");
        throw IException(IException::User, msg, _FILEINFO_);
      }
    }
    return pvlObjectToJSON(fitsPvl);
  }
 
 
  json fitsToJson(FileName fitsFile) {
    std::ifstream fileStream;
    try {
      fileStream.open(fitsFile.expanded().toLocal8Bit().constData(), std::ios::in  | std::ios::binary);
    }
    catch (IException &e) {
      QString msg = QString("Unable to open FITS formatted file [%1].")
                               .arg(fitsFile.toString());
      throw IException(e, IException::User, msg, _FILEINFO_);
    }
 
    return fitsToJson(fileStream);
  }
 
}