StdioDevice.h

/*
    StdioDevice.h 
    Copyright (c) 2025 Phil Schatzmann. All right reserved.
 
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.
 
    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.
 
    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#pragma once
 
#include <iostream>
#include <cstring>
#include <algorithm>
#include <deque>
#if defined(__unix__) || defined(__APPLE__)
#include <sys/ioctl.h>
#include <unistd.h>
#endif
#include <streambuf>
#include "api/Stream.h"
#include "api/Printable.h"
 
namespace arduino {
 
class StdioDevice : public Stream {
 public:
  StdioDevice(bool autoFlush = true) { auto_flush = autoFlush; }
 
  ~StdioDevice() {}
 
  operator bool() const {
    return true;
  }  // For classic while(!Serial) { ... } pattern for USB ready wait
 
  virtual void begin(int speed) {
    // nothing to be done
  }
 
  // Keep all of Print's overloads (double, long, unsigned, char, ...)
  // visible: declaring print()/println() here would otherwise hide them,
  // silently routing e.g. print(3.14, 2) to print(int, radix).
  using Stream::print;
  using Stream::println;
 
  virtual size_t print(const char* str) {
    std::cout << str;
    if (auto_flush) flush();
    return strlen(str);
  }
 
  virtual size_t println() { return println(""); }
 
  virtual size_t println(const char* str) {
    std::cout << str << "\n";
    if (auto_flush) flush();
    return strlen(str) + 1;
  }
 
  virtual size_t print(int val, int radix = DEC) {
    size_t result = Stream::print(val, radix);
    if (auto_flush) flush();
    return result;
  }
 
  virtual size_t println(int val, int radix = DEC) {
    size_t result = Stream::println(val, radix);
    if (auto_flush) flush();
    return result;
  }
 
  virtual size_t println(String& str) { return println(str.c_str()); }
 
  virtual size_t print(String& str) { return print(str.c_str()); }
 
  virtual size_t println(Printable& p) {
    size_t result = p.printTo(*this);
    std::cout << "\n";
    if (auto_flush) flush();
    return result + 1;
  }
 
  virtual size_t print(Printable& p) {
    auto result = p.printTo(*this);
    if (auto_flush) flush();
    return result;
  }
 
  void flush() override { std::cout.flush(); }
 
  virtual size_t write(const char* str, size_t len) {
    std::cout.write(str, len);
    if (auto_flush) flush();
    return len;
  }
 
  virtual size_t write(uint8_t* str, size_t len) {
    std::cout.write((const char*)str, len);
    if (auto_flush) flush();
    return len;
  }
  size_t write(const uint8_t* str, size_t len) override {
    std::cout.write((const char*)str, len);
    if (auto_flush) flush();
    return len;
  }
 
  virtual size_t write(int32_t value) {
    std::cout.put(value);
    if (auto_flush) flush();
    return 1;
  }
 
  size_t write(uint8_t value) override {
    std::cout.put(value);
    if (auto_flush) flush();
    return 1;
  }
 
  int available() override {
#if defined(__unix__) || defined(__APPLE__)
    fillInputBuffer();
    return static_cast<int>(inputBuffer_.size());
#endif
    return std::cin.rdbuf()->in_avail();
  }
 
  int read() override {
#if defined(__unix__) || defined(__APPLE__)
    if (available() == 0) return -1;
    const int value = inputBuffer_.front();
    inputBuffer_.pop_front();
    return value;
#else
    return std::cin.get();
#endif
  }
 
  int peek() override {
#if defined(__unix__) || defined(__APPLE__)
    return available() > 0 ? inputBuffer_.front() : -1;
#else
    return std::cin.peek();
#endif
  }
 
 protected:
  bool auto_flush = true;
 
#if defined(__unix__) || defined(__APPLE__)
 private:
  void fillInputBuffer() {
    int byteCount = 0;
    if (ioctl(STDIN_FILENO, FIONREAD, &byteCount) != 0 || byteCount <= 0) {
      return;
    }
 
    char buffer[256];
    const size_t bytesToRead = std::min(static_cast<size_t>(byteCount), sizeof(buffer));
    const ssize_t bytesRead = ::read(STDIN_FILENO, buffer, bytesToRead);
    if (bytesRead <= 0) {
      return;
    }
    inputBuffer_.insert(inputBuffer_.end(), buffer, buffer + bytesRead);
  }
 
  std::deque<unsigned char> inputBuffer_;
#endif
};
 
inline StdioDevice Serial;
#ifndef USE_RPI
inline StdioDevice Serial2;
#endif
 
}  // namespace arduino