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Diffstat (limited to 'kfile-plugins/torrent/bytetape.h')
| -rw-r--r-- | kfile-plugins/torrent/bytetape.h | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/kfile-plugins/torrent/bytetape.h b/kfile-plugins/torrent/bytetape.h new file mode 100644 index 00000000..1d8c8db2 --- /dev/null +++ b/kfile-plugins/torrent/bytetape.h @@ -0,0 +1,194 @@ +/* + * Copyright (c) 2003, 2004 Michael Pyne <michael.pyne@kdemail.net> + * + * This software 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. + * + * This software 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public + * License along with this library; see the file COPYING. + * If not, write to the Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ +#ifndef _BYTETAPE_H +#define _BYTETAPE_H + +#include <ksharedptr.h> + +#include <qcstring.h> + +class ByteTapeShared : public KShared +{ + public: + + unsigned int pos; +}; + +/** + * Class to simulate a seekable byte stream. Very similar to QByteArray, + * but the difference is that this class "knows" what a current position + * is. Also, the copy constructor will share the byte stream of the + * ByteTape being copied. This means that any copies made of an object of + * this class will share BOTH the data and the current position. This is + * by design. + * + * @author Michael Pyne <mpyne@grammarian.homelinux.net> + * @see QByteArray + */ +class ByteTape +{ + public: + + /** + * Constructs a new ByteTape object from @p array. The + * current position will be set to @p pos. + * + * @param array a data buffer to use for reading and writing. + * The tape will be fixed to the size of this buffer. + * @param pos the initial position of the tape head. It must be + * a position within the buffer contained in @p array. + */ + ByteTape (QByteArray &array, int pos = 0); + + /** + * Creates a ByteTape as a copy of @p tape. The newly created + * object will share both data and the current position with @p tape. + * This is done using reference counts. + * + * @param tape the ByteTape to copy + */ + ByteTape (const ByteTape &tape); + + /** + * Increments the current position by @p i. It is the responsibility + * of the function caller to ensure that the new position is in bounds. + * The position will be capped to remain in bounds regardless. + * + * @param i the amount to increment the current position by + * @return t reference to the object incremented + */ + ByteTape & operator += (const unsigned int i); + + /** + * Decrements the current position by @p i. It is the responsibility + * of the function caller to ensure that the new position is in bounds. + * Unlike a real Turing machine, attempting to decrement past the + * start will be capped to the beginning instead of crashing the + * computer. + * + * @param i the amount to decrement the current position by + * @return a reference to the object decremented + */ + ByteTape & operator -= (const unsigned int i); + + /** + * Increments the current position by 1. This is a postfix + * operator (i++). The current position will be capped to the end + * of the buffer. + * + * @return the object before the increment operation + */ + ByteTape operator ++ (int); + + /** + * Increments the current position by 1. This is a prefix + * operator (++i). The current position will be capped to the end + * of the buffer. + * + * @return a reference to the object incremented + */ + ByteTape & operator ++ (); + + /** + * Decrements the current position by 1. This is a postfix + * operator (i--). The current position will be capped to the start + * of the buffer. + * + * @return the object before the decrement operation + */ + ByteTape operator -- (int); + + /** + * Decrements the current position by 1. This is a prefix + * operator (--i). The current position will be capped to the start + * of the buffer. + * + * @return a reference to the object decremented + */ + ByteTape & operator -- (); + + /** + * Returns the byte within the array indexed by @p i. It is + * the responsibility of the caller to ensure that @p i is in bounds. + * Although out-of-range errors will be detected, no exceptions will + * be thrown. Since a reference is not returned, you won't be able + * to assign to the result. Example: tape[i] = 'a' will not work. + * + * The reason a reference isn't returned is because no exceptions are + * thrown by this class, and we can't return a reference to an out-of- + * bounds character. + * + * @param i the index of the byte to return + * @return the byte at the given index. 0 may be returned on error, + * but does not necessarily indicate an error. + */ + char operator [] (const unsigned int i); + + /** + * Returns the byte at the tape's current position. You can assign + * to the reference returned. + * + * @return a reference to the byte at the tape head's current position + */ + char &operator * (); + + /** + * Returns the position in memory of data at the given index, @p i. + * Unlike operator [], this function returns a pointer, so it can be + * used to access memory. + * + * @param i index of the byte to lookup. + * @return 0 if @p i is out of range, else the address of memory + * at that index + */ + char *at(const unsigned int i); + + /** + * Returns the current position of the tape head. + * + * @return the tape head's current position + */ + unsigned int pos() const { return m_shared->pos; } + + /** + * Sets the current position of the tape head to @p pos. If the + * position given is out-of-bounds, it will be capped to be within + * the array. + * + * @param pos the new position of the tape head + * @return whether the set operation was successful + */ + bool setPos(unsigned int pos); + + /** + * Returns a reference to the QByteArray used to hold all the data. + * + * @return the QByteArray used to hold the data + * @see QByteArray + */ + QByteArray &data() { return m_array; } + + private: + QByteArray &m_array; + KSharedPtr<ByteTapeShared> m_shared; +}; + +#endif /* _BYTETAPE_H */ + +// vim: set et ts=4 sw=4: |