#include <QtGui>
#include "dpx.h"
#include <iostream>

#define UINT_10_TO_8(val) \
(int)(((float)(val & 0x3FF) * (float)(0xFF)) / (float)(0x3FF))

#define DPX_PIXEL_RGB	50

QLabel* LoadDPX()
{
	QString strPath = QFileDialog::getOpenFileName(NULL, "Open DPX File",
						QDir::homePath(),
						"*.dpx",
						NULL, 0);
	if (strPath.isEmpty())
		return NULL;
	
	DPXHeader hdr;
	DPXImageHeader imgHdr;
	FILE* pf = fopen(strPath.toStdString().c_str(), "r");
	if (!pf)
		return NULL;
	if (!fread(&hdr, sizeof(hdr), 1, pf))
	{
		std::cerr << "Unable to read DPXHeader\n";
		fclose(pf);
		return NULL;
	}
	if (!fread(&imgHdr, sizeof(imgHdr), 1, pf))
	{
		std::cerr << "Unable to read DPXImageHeader\n";
		fclose(pf);
		return NULL;
	}
	
	// assume 10-bit image
	if (imgHdr.img_element[0].bit_size != 10)
	{
		std::cerr << "Only supports 10-bit DPX\n";
		fclose(pf);
		return NULL;
	}
	// and has RGB interleaved format
	if (imgHdr.img_element[0].descriptor != DPX_PIXEL_RGB)
	{
		std::cerr << "Has to be RGB Interleaved (desciptor == " 
			<< (int)imgHdr.img_element[0].descriptor << ")\n";
		fclose(pf);
		return NULL;
	}
	
	int nCount = imgHdr.img_width * imgHdr.img_height;
	size_t read_size = nCount * sizeof(uint32_t);
	
	QImage* pImg = new QImage(imgHdr.img_width, 
				imgHdr.img_height,
				QImage::Format_RGB32);
	
	// Jump to the right place
	fseek(pf, hdr.image_offset, SEEK_SET);
	
	if (!fread(pImg->bits(), sizeof(uint32_t), read_size, pf))
	{
		std::cerr << "Unable to read image data\n";
		delete pImg;
		fclose(pf);
		return NULL;
	}
	
	// now, align the bits properly...
	uint32_t* pData32 = (uint32_t*)pImg->bits();
	uint32_t val32;
	for (int i = 0; i < nCount; i++)
	{
		val32 = *pData32;
		if (imgHdr.img_element[0].packing == 1)
		{
			// 10-bit DPX packed using METHOD A
			// 2 bits padding in least significant bits
			// get rid of this bits
			val32 >>= 2;
		}
		*pData32++ = UINT_10_TO_8(val32) | (UINT_10_TO_8(val32>>10)<<8) | 
			(UINT_10_TO_8(val32>>20)<<16) | (0xFF<<24);
	}
	
	QLabel* pResult = new QLabel;
	pResult->setPixmap(QPixmap::fromImage(*pImg));
	return pResult;
}

int main(int argc, char** argv)
{
	QApplication app(argc, argv);
	QLabel* label = LoadDPX();
	if (!label)
		return 0;
	label->show();
	return app.exec();
}