pw_sys_io_stdio/sys_io.cc

// Copyright 2019 The Pigweed Authors
//
// Licensed under the Apache License, Version 2.0 (the "License"); you may not
// use this file except in compliance with the License. You may obtain a copy of
// the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
// License for the specific language governing permissions and limitations under
// the License.

#include "pw_sys_io/sys_io.h"

#include <cstdio>

namespace pw::sys_io {

Status ReadByte(std::byte* dest) {
  if (dest == nullptr) {
    return Status::FailedPrecondition();
  }

  int value = std::getchar();
  if (value == EOF) {
    return Status::ResourceExhausted();
  }
  *dest = static_cast<std::byte>(value);
  return OkStatus();
}

Status TryReadByte(std::byte*) {
  // TryReadByte() is not (yet) supported on hosts.
  return Status::Unimplemented();
}

Status WriteByte(std::byte b) {
  if (std::putchar(static_cast<char>(b)) == EOF) {
    return Status::Internal();
  }
  return OkStatus();
}

StatusWithSize WriteLine(const std::string_view& s) {
  size_t chars_written = 0;
  StatusWithSize size_result = WriteBytes(std::as_bytes(std::span(s)));
  if (!size_result.ok()) {
    return size_result;
  }
  chars_written += size_result.size();

  // Write trailing newline character.
  Status result = WriteByte(static_cast<std::byte>('\n'));
  if (result.ok()) {
    chars_written++;
  }

  return StatusWithSize(result, chars_written);
}

}  // namespace pw::sys_io