GPXSee/src/map/IMG/subfile.h

#ifndef SUBFILE_H
#define SUBFILE_H

#include <QVector>
#include <QFile>
#include "img.h"


#define BLOCK_BITS 12 /* 4096 bytes */

class SubFile
{
public:
	enum Type {Unknown, TRE, RGN, LBL, NET, NOD, TYP, GMP};

	class Handle
	{
	public:
		Handle(const SubFile *subFile)
		  : _file(0), _blockNum(-1), _blockPos(-1), _pos(-1)
		{
			if (subFile && subFile->_path) {
				_file = new QFile(*(subFile->_path));
				_file->open(QIODevice::ReadOnly);
				_data.resize(1U<<BLOCK_BITS);
			} else if (subFile)
				_data.resize(1U<<subFile->_img->blockBits());
		}
		~Handle() {delete _file;}

	private:
		friend class SubFile;

		QFile *_file;
		QByteArray _data;
		int _blockNum;
		int _blockPos;
		int _pos;
	};

	SubFile(IMG *img)
	  : _gmpOffset(0), _img(img), _blocks(new QVector<quint16>()), _path(0) {}
	SubFile(SubFile *gmp, quint32 offset) : _gmpOffset(offset), _img(gmp->_img),
	  _blocks(gmp->_blocks), _path(gmp->_path) {}
	SubFile(const QString &path)
	  : _gmpOffset(0), _img(0), _blocks(0), _path(new QString(path)) {}
	~SubFile()
	{
		if (!_gmpOffset) {
			delete _blocks;
			delete _path;
		}
	}

	void addBlock(quint16 block) {_blocks->append(block);}

	bool seek(Handle &handle, quint32 pos) const;
	quint32 pos(Handle &handle) const {return handle._pos;}

	template<typename T>
	bool readUInt8(Handle &handle, T &val) const
	{
		quint8 b;
		if (!readByte(handle, b))
			return false;
		val = b;
		return true;
	}

	template<typename T>
	bool readUInt16(Handle &handle, T &val) const
	{
		quint8 b0, b1;
		if (!(readByte(handle, b0) && readByte(handle, b1)))
			return false;
		val = b0 | ((quint16)b1) << 8;
		return true;
	}

	bool readInt16(Handle &handle, qint16 &val) const
	{
		if (!readUInt16(handle, (quint16&)val))
			return false;
		if((quint16)val > 0x7FFF)
			val = (val & 0x7FFF) - 0x8000;
		return true;
	}

	bool readUInt24(Handle &handle, quint32 &val) const
	{
		quint8 b0, b1, b2;
		if (!(readByte(handle, b0) && readByte(handle, b1)
		  && readByte(handle, b2)))
			return false;
		val = b0 | ((quint32)b1) << 8 | ((quint32)b2) << 16;
		return true;
	}

	bool readInt24(Handle &handle, qint32 &val) const
	{
		if (!readUInt24(handle, (quint32&)val))
			return false;
		if (val > 0x7FFFFF)
			val = (val & 0x7FFFFF) - 0x800000;
		return true;
	}

	bool readUInt32(Handle &handle, quint32 &val) const
	{
		quint8 b0, b1, b2, b3;
		if (!(readByte(handle, b0) && readByte(handle, b1)
		  && readByte(handle, b2) && readByte(handle, b3)))
			return false;
		val = b0 | ((quint32)b1) << 8 | ((quint32)b2) << 16
		  | ((quint32)b3) << 24;
		return true;
	}

	bool readVUInt32SW(Handle &hdl, quint32 bytes, quint32 &val) const
	{
		quint8 b;

		val = 0;
		for (quint32 i = bytes; i; i--) {
			if (!readByte(hdl, b))
				return false;
			val |= ((quint32)b) << ((i-1) * 8);
		}

		return true;
	}

	bool readVUInt32(Handle &hdl, quint32 &val) const;
	bool readVUInt32(Handle &hdl, quint32 bytes, quint32 &val) const;
	bool readVBitfield32(Handle &hdl, quint32 &bitfield) const;

	QString fileName() const {return _path ? *_path : _img->fileName();}

protected:
	quint32 _gmpOffset;

private:
	bool readByte(Handle &handle, quint8 &val) const
	{
		int blockSize = _img ? 1U<<_img->blockBits() : 1U<<BLOCK_BITS;
		val = handle._data.at(handle._blockPos++);
		handle._pos++;
		return (handle._blockPos >= blockSize)
		  ? seek(handle, handle._pos) : true;
	}

	IMG *_img;
	QVector<quint16> *_blocks;
	QString *_path;
};

#endif // SUBFILE_H