binfilehelper.h

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/***************************************************************************
                    binfilehelper.h - K Desktop Planetarium
                             -------------------
    begin                : Sat May 31 2008
    copyright            : (C) 2008 by Akarsh Simha
    email                : akarshsimha@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.                                   *
 *                                                                         *
 ***************************************************************************/


#ifndef BINFILEHELPER_H_
#define BINFILEHELPER_H_

#include <QString>
#include <QVector>

#include <cstdio>

class QString;

typedef struct dataElement {
    char name[10];
    qint8 size;
    quint8 type;
    qint32 scale;
} dataElement;


class BinFileHelper {

 public:

    BinFileHelper();
    
    ~BinFileHelper();

    static bool testFileExists( const QString &fileName );
    
    FILE *openFile(const QString &fileName);

    bool readHeader();

    void closeFile();

    int getErrorNumber();

    QString getError();

    struct dataElement getField(const QString &fieldName);

    bool isField(const QString &FieldName);

    inline bool propertiesUpdated() { return indexUpdated; }

    inline FILE *getFileHandle() { return fileHandle; }

    inline long getOffset(int id) { return (indexUpdated ? indexOffset.at( id ) : 0); }

    inline unsigned int getRecordCount(int id) { return (indexUpdated ? indexCount.at( id ) : 0); }

    inline unsigned long getRecordCount() { return (indexUpdated ? recordCount : 0); }

    inline bool getByteSwap() { return byteswap; }

    inline int guessRecordSize() { return (RSUpdated ? recordSize : 0); }

    inline void setRecordSize(int rs) { recordSize = rs; RSUpdated = true; }

    inline int getFieldCount() { return (FDUpdated ? nfields : 0); }

    inline QString getHeaderText() { return (preambleUpdated ? headerText : ""); }

    inline long getDataOffset() { return (indexUpdated ? dataOffset : 0); }

    inline long getIndexTableOffset() { return (FDUpdated ? itableOffset : 0); }

    static int unsigned_KDE_fseek( FILE *stream, quint32 offset, int whence );

    enum Errors {
    ERR_NULL,             // No error occurred
    ERR_FILEOPEN,         // File could not be opened
    ERR_FD_TRUNC,         // Field descriptor table is truncated
    ERR_INDEX_TRUNC,      // File ends prematurely, before expected end of index table
    ERR_INDEX_BADID,      // Index table has an invalid ID entry 
    ERR_INDEX_IDMISMATCH, // Index table has a mismatched ID entry [ID found in the wrong place]
    ERR_INDEX_BADOFFSET,  // Offset / Record count specified in the Index table is bad
    ERR_BADSEEK           // Premature end of file / bad seek while reading index table
    };

    enum dataType {
    DT_CHAR,              /* Character */
    DT_INT8,              /* 8-bit Integer */
    DT_UINT8,             /* 8-bit Unsigned Integer */
    DT_INT16,             /* 16-bit Integer */
    DT_UINT16,            /* 16-bit Unsigned Integer */
    DT_INT32,             /* 32-bit Integer */
    DT_UINT32,            /* 32-bit Unsigned Integer */
    DT_CHARV,             /* Fixed-length array of characters */
    DT_STR,               /* Variable length array of characters, either terminated by NULL or by the limit on field size */
    DT_SPCL = 128         /* Flag indicating that the field requires special treatment (eg: Different bits may mean different things) */
    };

 private:

    enum Errors  __readHeader();

    void clearFields();

    void init();

    FILE *fileHandle;                     // Handle to the file.
    QVector<unsigned long> indexOffset;   // Stores offsets corresponding to each index table entry
    QVector<unsigned int> indexCount;     // Stores number of records under each index table entry
    bool indexUpdated;                    // True if the data from the index, and associated properties have been updated
    bool FDUpdated;                       // True if the data from the Field Descriptor, and associated properties have been updated
    bool RSUpdated;                       // True if the recordSize parameter is set correctly, either manually or bye reading the FD
    bool preambleUpdated;                 // True if the data from the preamble and associated properties have been updated
    enum Errors errnum;                   // Stores the number corresponding to the previous error
    bool byteswap;                        // True if byteswapping should be done
    int recordSize;                       // Stores the size of a record in bytes for quick retrieval
    QVector<dataElement *> fields;        // Maintains a list of fields in the file, along with relevant details
    QString headerText;                   // Stores the file header text
    qint16 nfields;                       // Stores the number of fields as indicated by the field descriptor
    quint32 indexSize;                    // Stores the size of the index table in number of entries
    long itableOffset;                    // Stores the offset position of the first index table entry
    long dataOffset;                      // Stores the offset position of the start of data
    QString errorMessage;                 // Stores the most recent 'unread' error message
    unsigned long recordCount;            // Stores the total number of records in the file
    quint8 versionNumber;                 // Stores the version number of the file
};

#endif