Break down iPhone photo with depth (jpg file with Multi-picture Format) https://wordpress.com/post/initialneil.wordpress.com/254

breakdown-jpg.cpp

#include <fstream>
#include <vector>
#include <string>

using namespace std;

int main(int argc, char **argv)
{
	string fn = argc > 1 ? argv[1] : "";
	ifstream in(fn, ios::binary);
	if (!in.is_open())
		return -1;

	ofstream fout;

	long addr = 0;
	int n_jpg = 0, n_out = 0;
	std::vector<int> stack;

	// c0 is the last, c is the current
	unsigned char c0 = 0, c = 0;

	// Skips potential padding between markers
	while (!in.eof()) {
		c = in.get();
		//printf("%02X ", c);

		// find jpg start
		if (c0 == 0xff && c == 0xd8) {
			for (int i = 0; i < stack.size(); ++i)
				printf("  ");
			printf("|-- [image %d] start at %ld\n", n_jpg, addr - 1);

			// open output file
			if (stack.empty()) {
				fout.open(fn + "-" + to_string(n_out) + ".jpg", ios::binary | ios::out);
				fout.write((char*)&c0, sizeof(c0));
				n_out++;
			}

			// push to jpg stack
			stack.push_back(n_jpg);
			n_jpg++;
		}

		// write current uchar
		fout.write((char*)&c, sizeof(c));

		// check jpg finished
		if (c0 == 0xff && c == 0xd9) {
			for (int i = 0; i < stack.size() - 1; ++i)
				printf("  ");
			printf("|-- [image %d] end at %ld\n", stack.back(), addr);

			stack.pop_back();

			// close finished file
			if (stack.empty())
				fout.close();
		}

		c0 = c;
		addr++;
	}

	return 0;
}