Keyboard.h

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// SPDX-License-Identifier: Apache-2.0
// Copyright 2023 Inria
 
#pragma once
 
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/select.h>
#include <termios.h>
#include <unistd.h>
 
#include <chrono>
#include <iostream>
#include <string>
 
#include "vulp/observation/Source.h"
 
using std::chrono::duration_cast;
using std::chrono::milliseconds;
using std::chrono::system_clock;
 
constexpr ssize_t kMaxKeyBytes = 3;
 
constexpr int64_t kPollingIntervalMS = 50;
 
// Scan codes for arrow keys
constexpr unsigned char UP_BYTES[] = {0x1B, 0x5B, 0x41};
constexpr unsigned char DOWN_BYTES[] = {0x1B, 0x5B, 0x42};
constexpr unsigned char RIGHT_BYTES[] = {0x1B, 0x5B, 0x43};
constexpr unsigned char LEFT_BYTES[] = {0x1B, 0x5B, 0x44};
 
inline bool is_lowercase_alpha(unsigned char c) {
  return 0x61 <= c && c <= 0x7A;
}
inline bool is_uppercase_alpha(unsigned char c) {
  return 0x41 <= c && c <= 0x5A;
}
inline bool is_printable_ascii(unsigned char c) {
  return 0x20 <= c && c <= 0x7F;
}
 
namespace vulp::observation::sources {
enum class Key {
  UP,
  DOWN,
  LEFT,
  RIGHT,
  W,
  A,
  S,
  D,
  X,
  NONE,    // No key pressed
  UNKNOWN  // Map everything else to this key
};
 
class Keyboard : public Source {
 public:
  Keyboard();
 
  ~Keyboard() override;
 
  inline std::string prefix() const noexcept final { return "keyboard"; }
 
  void write(Dictionary& output) final;
 
 private:
  bool read_event();
 
  Key map_char_to_key(unsigned char* buf);
 
  unsigned char buf_[kMaxKeyBytes];
 
  Key key_code_;
 
  bool key_pressed_;
 
  system_clock::time_point last_key_poll_time_;
};
 
}  // namespace vulp::observation::sources