dt2dtb.cpp

#include <iostream>
#include <fstream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <string>
#include <sys/stat.h>

using namespace std;

vector<uint8_t> readBytes(string filename) {
	ifstream ifs(filename, ios::binary | ios::ate);

	ifstream::pos_type pos = ifs.tellg();
	vector<uint8_t> result(pos);

	ifs.seekg(0, ios::beg);
	ifs.read((char*) &result[0], pos);

	return result;
}

void writeBytes(string filename, vector<uint8_t> data, size_t start, size_t length) {
	ofstream ofs(filename, ios::out | ios::binary);
	ofs.write((char*) &data[start], length);
}

uint32_t bytesToUint32(vector<uint8_t> data, size_t start) {
	uint32_t r = 0;
	for(size_t i = start + 3; i >= start; i--) {
		r <<= 8;
		r |= data[i];
	}
	return r;
}

int main(int argc, char *argv[]) {
	vector<string> args(argv + 1, argv + argc);
	if(args.size() < 2) {
		return -1;
	}

	string dtPath = args[0];
	string dtbPath = args[1];

	struct stat st;
	if (stat(dtPath.c_str(), &st) == -1) {
	    return -1;
	}	
	if (stat(dtbPath.c_str(), &st) == -1) {
	    mkdir(dtbPath.c_str(), 0766);
	}

	vector<uint8_t> dtData = readBytes(dtPath);
	vector<uint32_t> dtbOffsets;

	uint32_t numDtbs = bytesToUint32(dtData, 4 * 2);

	for(uint32_t i = 0; i < numDtbs; i++) {
		cout << "dtb #" << i << "\n"; 

		uint32_t headerOffset = 4 * 3 + 4 * 10 * i;
		uint32_t offset = bytesToUint32(dtData, headerOffset + 4 * 8);
		uint32_t size = bytesToUint32(dtData, headerOffset + 4 * 9);

		cout << "offset: " << offset << "\n";
		cout << "size: " << size << "\n";

		if(find(dtbOffsets.begin(), dtbOffsets.end(), offset) == dtbOffsets.end()) {
			string filename = dtbPath + "/" + to_string(i) + ".dtb";
			writeBytes(filename, dtData, offset, size);
			dtbOffsets.push_back(offset);
		}

		cout << "\n";
	}
	return 0;
}