#include <cstdint>
#include <string>
#include <cstring>
#include <memory>

class BufferedReader {
 public:
  explicit BufferedReader(PackageStream *stream) {
    ps_ = stream;
    buf_ = new char[ps_->PackageLen()];
    pos_ = 0;
    buf_size_ = 0;
  }
  int32_t Read(char *output_buffer, int32_t buffer_len) {
    int32_t pos;
    for (pos = 0; pos < buffer_len; ++pos, ++pos_) {
      if (pos_ == buf_size_) {
        buf_size_ = ps_->ReadPackage(buf_);
        pos_ = 0;
        if (buf_size_ == 0) break;
      }
      output_buffer[pos] = buf_[pos_];
    }
    return pos;
  }
  
 private:
  PackageStream *ps_;
  char *buf_;
  int buf_size_;
  int pos_;
};