File indexing completed on 2024-04-28 04:40:01

 /* This file is part of the KDE project
    Copyright (C) 2009,2010 KO GmbH <jos.van.den.oever@kogmbh.com>
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.
 
    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.
 
    You should have received a copy of the GNU Library General Public License
    along with this library; see the file COPYING.LIB.  If not, write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
 */
 #ifndef LEINPUTSTREAM_H
 #define LEINPUTSTREAM_H
 
 #include <QIODevice>
 #include <QDataStream>
 #include <QDebug>
 #include <exception>
 
 class IOException : public std::exception {
 public:
     const QString msg;
     IOException() {}
     explicit IOException(const QString &m) :msg(m) {}
     ~IOException() throw() {}
 };
 
 class IncorrectValueException : public IOException {
 public:
     explicit IncorrectValueException(const QString &msg) :IOException(msg) {}
     IncorrectValueException(qint64 /*pos*/, const char* errMsg) :IOException(errMsg) {}
     ~IncorrectValueException() throw() {}
 };
 
 class EOFException : public IOException {
 public:
     explicit EOFException(const QString &msg = QString()) :IOException(msg) {}
     ~EOFException() throw() {}
 };
 
 class LEInputStream {
 private:
     QIODevice* input;
     QDataStream data;
 
     qint64 maxPosition;
 
     qint8 bitfieldpos;
     quint8 bitfield;
 
     quint8 getBits(quint8 n) {
         if (bitfieldpos < 0) {
             bitfield = readuint8();
             bitfieldpos = 0;
         }
         quint8 v = bitfield >> bitfieldpos;
         bitfieldpos += n;
         if (bitfieldpos == 8) {
             bitfieldpos = -1;
         } else if (bitfieldpos > 8) {
             throw IOException("Bitfield does not have enough bits left.");
         }
         return v;
     }
     void checkForLeftOverBits() const {
         if (bitfieldpos >= 0) {
             throw IOException("Cannot read this type halfway through a bit operation.");
         }
     }
     void checkStatus() const {
         if (data.status() != QDataStream::Ok) {
             if (data.status() == QDataStream::ReadPastEnd) {
                 throw EOFException("Stream claims to be at the end at position: " + QString::number(input->pos()) + "." );
             }
             throw IOException("Error reading data at position " + QString::number(input->pos()) + ".");
         }
     }
 
 public:
     class Mark {
     friend class LEInputStream;
     private:
         QIODevice* input;
         qint64 pos;
         explicit Mark(QIODevice *in) :input(in), pos((in) ?in->pos() :0) {}
     public:
         Mark() :input(0), pos(0) {} 
     };
 
     LEInputStream(QIODevice* in) :input(in), data(in) {
         maxPosition = 0;
         bitfield = 0;
         bitfieldpos = -1;
         data.setByteOrder(QDataStream::LittleEndian);
     }
 
     Mark setMark() { return Mark(input); }
     void rewind(const Mark& m) {
         maxPosition = qMax(input->pos(), maxPosition);
         if (!m.input || !m.input->seek(m.pos)) {
             throw IOException("Cannot rewind.");
         }
         data.resetStatus();
     }
 
     bool readbit() {
         quint8 v = getBits(1) & 1;
         return v == 1;
     }
 
     quint8 readuint2() {
         return getBits(2) & 3;
     }
 
     quint8 readuint3() {
         return getBits(3) & 0x7;
     }
 
     quint8 readuint4() {
         return getBits(4) & 0xF;
     }
 
     quint8 readuint5() {
         return getBits(5) & 0x1F;
     }
 
     quint8 readuint6() {
         return getBits(6) & 0x3F;
     }
 
     quint8 readuint7() {
         return getBits(7) & 0x7F;
     }
 
     quint16 readuint9() {
         quint8 a = readuint8();
         quint8 b = getBits(1) & 0x1;
         return (b << 8) | a;
     }
 
     quint16 readuint12() {
         // we assume there are 4 bits left
         quint8 a = getBits(4) & 0xF;
         quint8 b = readuint8();
         return (b << 4) | a;
     }
 
     quint16 readuint13() {
         quint8 a = getBits(5) & 0x1F;
         quint8 b = readuint8();
         return (b << 5) | a;
     }
 
     quint16 readuint14() {
         quint16 v;
         if (bitfieldpos < 0) {
             quint8 a = readuint8();
             quint8 b = getBits(6) & 0x3F;
             v = (b << 8) | a;
         } else if (bitfieldpos == 2) {
             quint8 a = getBits(6) & 0x3F;
             quint8 b = readuint8();
             v = (b << 6) | a;
         } else {
             throw IOException("Cannot read this type halfway through a bit operation.");
         }
         return v;
     }
 
     quint16 readuint15() {
         // we assume there are 7 bits left
         quint8 a = getBits(7) & 0x7F;
         quint8 b = readuint8();
         return (b << 7) | a;
     }
 
     quint32 readuint20() {
         quint32 v;
         if (bitfieldpos < 0) {
             quint8 a = readuint8();
             quint8 b = readuint8();
             quint8 c = getBits(4) & 0xF;
             v = (c << 16) | (b << 8) | a;
         } else if (bitfieldpos == 4) {
             quint8 a = getBits(4) & 0xF;
             quint8 b = readuint8();
             quint8 c = readuint8();
             v = (c << 12) | (b << 4) | a;
         } else {
             throw IOException("Cannot read this type halfway through a bit operation.");
         }
         return v;
     }
 
     quint32 readuint30() {
         checkForLeftOverBits();
         quint8 a = readuint8();
         quint8 b = readuint8();
         quint8 c = readuint8();
         quint8 d = getBits(6) & 0x3F;
         return (d << 24) | (c << 16) | (b << 8) | a;
     }
 
     quint8 readuint8() {
         checkForLeftOverBits();
         quint8 a;
         data >> a;
         checkStatus();
         return a;
     }
 
     qint16 readint16() {
         checkForLeftOverBits();
         qint16 v;
         data >> v;
         checkStatus();
         return v;
     }
 
     quint16 readuint16() {
         checkForLeftOverBits();
         quint16 v;
         data >> v;
         checkStatus();
         return v;
     }
 
     quint32 readuint32() {
         checkForLeftOverBits();
         quint32 v;
         data >> v;
         checkStatus();
         return v;
     }
 
     qint32 readint32() {
         checkForLeftOverBits();
         qint32 v;
         data >> v;
         checkStatus();
         return v;
     }
 
     void readBytes(QByteArray& b) {
         int offset = 0;
         int todo = b.size();
         while (todo > 0) { // do not enter loop if array size is 0
             int nread = data.readRawData(b.data() + offset, todo);
             if (nread == -1 || nread == 0) {
                 throw EOFException();// TODO: differentiate
             }
             todo -= nread;
             offset += nread;
         }
     }
 
     void skip(int len) {
         data.skipRawData(len);
     }
 
     qint64 getPosition() const { return input->pos(); }
 
     qint64 getMaxPosition() const { return qMax(input->pos(), maxPosition); }
     qint64 getSize() const { return input->size(); }
 };
 
 #endif