uart_output_stream.cpp

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#if (defined ESP_PLATFORM || defined ROO_TESTING)
 
#include "roo_io/uart/esp32/uart_output_stream.h"
 
#include "driver/uart.h"
#ifndef ROO_TESTING
#include "hal/uart_ll.h"
#endif
 
namespace roo_io {
 
size_t Esp32UartOutputStream::tryWrite(const byte* buf, size_t count) {
  if (!isOpen() || count == 0) return 0;
  size_t avail_for_write = available_for_write();
  if (count > avail_for_write) count = avail_for_write;
  if (count == 0) return 0;
  int result = uart_write_bytes(port_, (const char*)buf, count);
  if (result < 0) {
    status_ = roo_io::kWriteError;
    return 0;
  }
  return result;
}
 
size_t Esp32UartOutputStream::write(const byte* buf, size_t count) {
  if (!isOpen() || count == 0) return 0;
  size_t avail_for_write = available_for_write();
  if (count > avail_for_write) count = avail_for_write;
  if (count == 0) ++count;  // Force at least one byte to be written.
  int result = uart_write_bytes(port_, (const char*)buf, count);
  if (result < 0) {
    status_ = roo_io::kWriteError;
    return 0;
  }
  return result;
}
 
size_t Esp32UartOutputStream::writeFully(const byte* buf, size_t count) {
  if (!isOpen() || count == 0) return 0;
  int result = uart_write_bytes(port_, (const char*)buf, count);
  if (result < 0) {
    status_ = roo_io::kWriteError;
    return 0;
  }
  return result;
}
 
void Esp32UartOutputStream::flush() {
  // No-op.
}
 
void Esp32UartOutputStream::close() {
  if (status_ == kOk) {
    status_ = kClosed;
  }
}
 
size_t Esp32UartOutputStream::available_for_write() const {
#ifdef ROO_TESTING
  return 64;  // Arbitrary large number for testing.
#else
  uint32_t available = uart_ll_get_txfifo_len(UART_LL_GET_HW(port_));
  size_t tx_ringbuf_available = 0;
  if (uart_get_tx_buffer_free_size(port_, &tx_ringbuf_available) == ESP_OK) {
    available = tx_ringbuf_available == 0 ? available : tx_ringbuf_available;
  }
  return available;
#endif
}
 
}  // namespace roo_io
 
#endif  // (defined ESP_PLATFORM || defined ROO_TESTING)