Function compressData

source/core/StarCompression.cpp:11–46

namespace Star {

void compressData(ByteArray const& in, ByteArray& out, CompressionLevel compression) {
  out.clear();

  if (in.empty())
    return;

  const size_t BUFSIZE = 32 * 1024;
  auto tempBuffer = std::make_unique<unsigned char[]>(BUFSIZE);

  z_stream strm{};
  strm.zalloc = Z_NULL;
  strm.zfree = Z_NULL;
  strm.opaque = Z_NULL;
  int deflate_res = deflateInit(&strm, compression);
  if (deflate_res != Z_OK)
    throw IOException(strf("Failed to initialise deflate ({})", deflate_res));

  strm.next_in = (unsigned char*)in.ptr();
  strm.avail_in = in.size();
  strm.next_out = tempBuffer.get();
  strm.avail_out = BUFSIZE;
  while (deflate_res == Z_OK) {
    deflate_res = deflate(&strm, Z_FINISH);
    if (strm.avail_out == 0) {
      out.append((char const*)tempBuffer.get(), BUFSIZE);
      strm.next_out = tempBuffer.get();
      strm.avail_out = BUFSIZE;
    }
  }
  deflateEnd(&strm);

  if (deflate_res != Z_STREAM_END)
    throw IOException(strf("Internal error in uncompressData, deflate_res is {}", deflate_res));

  out.append((char const*)tempBuffer.get(), BUFSIZE - strm.avail_out);
}

ByteArray compressData(ByteArray const& in, CompressionLevel compression) {
  ByteArray out = ByteArray::withReserve(in.size());