ksparser.cpp

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/***************************************************************************
                          KSParser.cpp  -  K Desktop Planetarium
                             -------------------
    begin                : 2012/24/06
    copyright            : (C) 2012 by Rishab Arora
    email                : ra.rishab@gmail.com
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#include "ksparser.h"
#include <kdebug.h>
#include <klocale.h>

const int KSParser::EBROKEN_INT = 0;
const double KSParser::EBROKEN_DOUBLE = 0.0;
const float KSParser::EBROKEN_FLOAT = 0.0;
const QString KSParser::EBROKEN_QSTRING = "Null";
const bool KSParser::parser_debug_mode_ = false;

KSParser::KSParser(const QString &filename, const char comment_char,
                   const QList< QPair<QString, DataTypes> > &sequence,
                   const char delimiter)
    : filename_(filename), comment_char_(comment_char),
      name_type_sequence_(sequence), delimiter_(delimiter) {
    if (!file_reader_.openFullPath(filename_)) {
        kWarning() <<"Unable to open file: "<< filename;
        readFunctionPtr = &KSParser::DummyRow;
    } else {
        readFunctionPtr = &KSParser::ReadCSVRow;
        kDebug() <<"File opened: "<< filename;
    }
}

KSParser::KSParser(const QString &filename, const char comment_char,
                   const QList< QPair<QString, DataTypes> > &sequence,
                   const QList<int> &widths)
    : filename_(filename), comment_char_(comment_char),
      name_type_sequence_(sequence), width_sequence_(widths) {
    if (!file_reader_.openFullPath(filename_)) {
        kWarning() <<"Unable to open file: "<< filename;
        readFunctionPtr = &KSParser::DummyRow;
    } else {
        readFunctionPtr = &KSParser::ReadFixedWidthRow;
        kDebug() <<"File opened: "<< filename;
    }
}

QHash<QString, QVariant>  KSParser::ReadNextRow() {
    return (this->*readFunctionPtr)();
}

QHash<QString, QVariant>  KSParser::ReadCSVRow() {
    bool read_success = false;
    QString next_line;
    QStringList separated;
    QHash<QString, QVariant> newRow;

    while (file_reader_.hasMoreLines() && read_success == false) {
        next_line = file_reader_.readLine();
        if (next_line.mid(0,1)[0] == comment_char_) continue;
        separated = next_line.split(delimiter_);
        /*
            * 1) split along delimiter eg. comma (,)
            * 2) check first and last characters.
            *    if the first letter is  '"',
            *    then combine the nexto ones in it till
            *    till you come across the next word which
            *    has the last character as '"'
            *    (CombineQuoteParts
            *
        */
        if (separated.length() == 1) continue; // Length will be 1 if there
                                               // is no delimiter

        separated = CombineQuoteParts(separated);  // At this point, the
                                     // string has been split
                                    // taking the quote marks into account

        // Check if the generated list has correct size
        // If not, continue to next row. (i.e SKIP INCOMPLETE ROW)
        if (separated.length() != name_type_sequence_.length())
            continue;

        for (int i = 0; i < name_type_sequence_.length(); i++) {
           bool ok;
           newRow[name_type_sequence_[i].first] =
           ConvertToQVariant(separated[i], name_type_sequence_[i].second, ok);
           if (!ok && parser_debug_mode_) {
             kDebug() << name_type_sequence_[i].second
                      <<"Failed at field: "
                      << name_type_sequence_[i].first
                      << " & next_line : " << next_line;
           }
        }
        read_success = true;
    }
   /*
    * This signifies that someone tried to read a row
    * without checking if HasNextRow is true.
    * OR
    * The file was truncated OR the file ends with one or more '\n'
    */
    if (file_reader_.hasMoreLines() == false && newRow.size()<=1)
      newRow = DummyRow();
    return newRow;
}

QHash<QString, QVariant>  KSParser::ReadFixedWidthRow() {
    if (name_type_sequence_.length() != (width_sequence_.length() + 1)) {
        // line length is appendeded to width_sequence_ by default.
        // Hence, the length of width_sequence_ is one less than
        // name_type_sequence_
        kWarning() << "Unequal fields and widths! Returning dummy row!";
        Q_ASSERT( false ); // Make sure that in Debug mode, this condition generates an abort.
        return DummyRow();
    }

    bool read_success = false;
    QString next_line;
    QStringList separated;
    QHash<QString, QVariant> newRow;
    int total_min_length = 0;

    foreach(const int width_value, width_sequence_) {
      total_min_length += width_value;
    }
    while (file_reader_.hasMoreLines() && read_success == false) {
      /*
       * Steps:
       * 1) Read Line
       * 2) If it is a comment, loop again
       * 3) If it is too small, loop again
       * 4) Else, a) Break it down according to widths
       *          b) Convert each broken down unit to appropriate value
       *          c) set read_success to True denoting we have a valid
       *             conversion
      */
        next_line = file_reader_.readLine();
        if (next_line.mid(0,1)[0] == comment_char_) continue;
        if (next_line.length() < total_min_length) continue;

        int curr_width = 0;
        for (int n_split = 0; n_split < width_sequence_.length(); n_split++) {
            // Build separated stringlist. Then assign it afterwards.
            QString temp_split;
            temp_split = next_line.mid(curr_width, width_sequence_[n_split]);
                        // Don't use at(), because it crashes on invalid index
            curr_width += width_sequence_[n_split];
            separated.append(temp_split.trimmed());
        }
        separated.append(next_line.mid(curr_width).trimmed());  // Append last segment

        // Conversions
        for (int i = 0; i < name_type_sequence_.length(); ++i) {
           bool ok;
           newRow[name_type_sequence_[i].first] =
           ConvertToQVariant(separated[i], name_type_sequence_[i].second, ok);
           if (!ok && parser_debug_mode_) {
             kDebug() << name_type_sequence_[i].second
                      <<"Failed at field: "
                      << name_type_sequence_[i].first
                      << " & next_line : " << next_line;
           }
        }
        read_success = true;
    }
   /*
    * This signifies that someone tried to read a row
    * without checking if HasNextRow is true.
    * OR
    * The file was truncated OR the file ends with one or more '\n'
    */
    if (file_reader_.hasMoreLines() == false && newRow.size()<=1)
      newRow = DummyRow();
    return newRow;
}

QHash<QString, QVariant>  KSParser::DummyRow() {
    kWarning() << "File named " << filename_ << " encountered an error while reading";
    QHash<QString, QVariant> newRow;
    for (int i = 0; i < name_type_sequence_.length(); ++i) {
           switch (name_type_sequence_[i].second) {
                case D_QSTRING:
                    newRow[name_type_sequence_[i].first] = EBROKEN_QSTRING;
                    break;
                case D_DOUBLE:
                    newRow[name_type_sequence_[i].first] = EBROKEN_DOUBLE;
                    break;
                case D_INT:
                    newRow[name_type_sequence_[i].first] = EBROKEN_INT;
                    break;
                case D_FLOAT:
                    newRow[name_type_sequence_[i].first] = EBROKEN_FLOAT;
                    break;
            }
        }
    return newRow;
}

bool KSParser::HasNextRow() {
    return file_reader_.hasMoreLines();
}

void KSParser::SetProgress(QString msg, int total_lines, int step_size) {
    file_reader_.setProgress(i18n("Loading NGC/IC objects"),
                             total_lines, step_size);
}

void KSParser::ShowProgress() {
    file_reader_.showProgress();
}

QList< QString > KSParser::CombineQuoteParts(QList<QString> &separated) {
    QString iter_string;
    QList<QString> quoteCombined;
    QStringList::const_iterator iter;

    if (separated.length() == 0) {
      kDebug() << "Cannot Combine empty list";
    } else {
      /* Algorithm:
       * In the following steps, 'word' implies a unit from 'separated'.
       * i.e. separated[0], separated[1] etc are 'words'
       *
       * 1) Read a word
       * 2) If word does not start with \" add to final expression. Goto 1)
       * 3) If word starts with \", push to queue
       * 4) If word ends with \", empty queue and join each with delimiter.
       *    Add this to final expression. Go to 6)
       * 5) Read next word. Goto 3) until end of list of words is reached
       * 6) Goto 1) until end of list of words is reached
      */
      iter = separated.constBegin();

      while (iter != separated.constEnd()) {
          QList <QString> queue;
          iter_string = *iter;

          if (iter_string.indexOf("\"") == 0) {  // if (quote mark is the first character)
              iter_string = (iter_string).remove(0,1);  // remove the quote at the start
              while (iter_string.lastIndexOf('\"') != (iter_string.length()-1) &&
                      iter != separated.constEnd()) {  // handle stuff between parent quotes
                  queue.append((iter_string));
                  ++iter;
                  iter_string = *iter;
              }
              iter_string.chop(1);  // remove the quote at the end
              queue.append(iter_string);
          } else {
              queue.append(iter_string);
          }

          QString col_result;
          foreach(const QString &join, queue)
              col_result += (join + delimiter_);
          col_result.chop(1);  // remove extra delimiter
          quoteCombined.append(col_result);
          ++iter;
      }
    }
    return quoteCombined;
}

QVariant KSParser::ConvertToQVariant(const QString &input_string,
                                     const KSParser::DataTypes &data_type,
                                     bool &ok) {
  ok = true;
  QVariant converted_object;
  switch (data_type) {
    case D_QSTRING:
    case D_SKIP:
      converted_object = input_string;
      break;
    case D_DOUBLE:
      converted_object = input_string.trimmed().toDouble(&ok);
      if (!ok)
        converted_object = EBROKEN_DOUBLE;
      break;
    case D_INT:
      converted_object = input_string.trimmed().toInt(&ok);
      if (!ok)
        converted_object = EBROKEN_INT;
      break;
    case D_FLOAT:
      converted_object = input_string.trimmed().toFloat(&ok);
      if (!ok)
        converted_object = EBROKEN_FLOAT;
      break;
  }
  return converted_object;
}