This is a starting point for how to compress data from a buffer using heatshrink and write the data into an output buffer:
Note that this has not been thoroughly tested, but at least it doesn’t crash 🙂
// TODO Your code goes here
const size_t outbuf_size = filesize + 128;
char* outbuf = new char[outbuf_size];
heatshrink_encoder* encoder = heatshrink_encoder_alloc(10, 4);
size_t tosink = filesize;
size_t output_size = 0;
while(tosink > 0) {
size_t sunk = 0;
auto err = heatshrink_encoder_sink(encoder, reinterpret_cast<uint8_t*>(buf), (size_t)filesize, &sunk);
if(err != HSER_SINK_OK) {
std::cerr << "Error sinking data" << std::endl;
break;
}
if(sunk == 0) {
std::cerr << "No data sunk" << std::endl;
break;
}
// Check how much has been sunk & update tosink
tosink -= sunk;
// Poll for output
size_t polled = 0;
auto err2 = heatshrink_encoder_poll(encoder, reinterpret_cast<uint8_t*>(outbuf + output_size), outbuf_size - output_size, &polled);
if(err2 == HSER_POLL_ERROR_NULL || err2 == HSER_POLL_ERROR_MISUSE) {
std::cerr << "Error polling data" << std::endl;
break;
}
output_size += polled;
}
// Input data finished
auto err3 = heatshrink_encoder_finish(encoder);
// Poll for final output
// Poll for output
size_t polled = 0;
auto err2 = heatshrink_encoder_poll(encoder, reinterpret_cast<uint8_t*>(outbuf + output_size), outbuf_size - output_size, &polled);
if(err2 == HSER_POLL_ERROR_NULL || err2 == HSER_POLL_ERROR_MISUSE) {
std::cerr << "Error finally polling data" << std::endl;
}
output_size += polled;
cout << "Original size: " << filesize << ", compressed size: " << output_size << endl;
