Roll forward to cl/338482889

Signed-off-by: Alexey Polyudov <apolyudov@google.com>
Change-Id: Ic2bdb234e89f3c5860d1b483dd4bce689f13d057

cpp/platform/base/base_input_stream.cc

@@ -0,0 +1,99 @@
+// Copyright 2020 Google LLC
+//
+// 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 "platform/base/base_input_stream.h"
+
+namespace location {
+namespace nearby {
+
+ExceptionOr<ByteArray> BaseInputStream::Read(std::int64_t size) {
+  if (!IsAvailable(size)) {
+    return ExceptionOr<ByteArray>{Exception::kIo};
+  }
+
+  ByteArray read_bytes{static_cast<size_t>(size)};
+  if (read_bytes.CopyAt(/*offset=*/0, buffer_,
+                        /*source_offset=*/position_)) {
+    position_ += size;
+    return ExceptionOr<ByteArray>{read_bytes};
+  } else {
+    return ExceptionOr<ByteArray>{Exception::kIo};
+  }
+}
+
+std::uint8_t BaseInputStream::ReadUint8() {
+  constexpr int byte_size = sizeof(std::uint8_t);
+  ByteArray read_bytes = ReadBytes(byte_size);
+  if (read_bytes.Empty() || read_bytes.size() != byte_size) {
+    return -1;
+  }
+
+  return read_bytes.data()[0];
+}
+
+std::uint16_t BaseInputStream::ReadUint16() {
+  constexpr int byte_size = sizeof(std::uint16_t);
+  ByteArray read_bytes = ReadBytes(byte_size);
+  if (read_bytes.Empty() || read_bytes.size() != byte_size) {
+    return -1;
+  }
+
+  // Convert from network order.
+  const char *data = read_bytes.data();
+  return static_cast<uint16_t>(data[0]) << 8 | static_cast<uint16_t>(data[1]);
+}
+
+std::uint32_t BaseInputStream::ReadUint32() {
+  constexpr int byte_size = sizeof(std::uint32_t);
+  ByteArray read_bytes = ReadBytes(byte_size);
+  if (read_bytes.Empty() || read_bytes.size() != byte_size) {
+    return -1;
+  }
+
+  // Convert from network order.
+  const char *data = read_bytes.data();
+  return static_cast<uint32_t>(data[0]) << 24 |
+         static_cast<uint32_t>(data[1]) << 16 |
+         static_cast<uint32_t>(data[2]) << 8 | static_cast<uint32_t>(data[3]);
+}
+
+std::uint64_t BaseInputStream::ReadUint64() {
+  constexpr int byte_size = sizeof(std::uint64_t);
+  ByteArray read_bytes = ReadBytes(byte_size);
+  if (read_bytes.Empty() || read_bytes.size() != byte_size) {
+    return -1;
+  }
+
+  // Convert from network order.
+  const char *data = read_bytes.data();
+  return static_cast<uint64_t>(data[0]) << 56 |
+         static_cast<uint64_t>(data[1]) << 48 |
+         static_cast<uint64_t>(data[2]) << 40 |
+         static_cast<uint64_t>(data[3]) << 32 |
+         static_cast<uint64_t>(data[4]) << 24 |
+         static_cast<uint64_t>(data[5]) << 16 |
+         static_cast<uint64_t>(data[6]) << 8 | static_cast<uint64_t>(data[7]);
+}
+
+ByteArray BaseInputStream::ReadBytes(int size) {
+  ExceptionOr<ByteArray> read_bytes_result = Read(size);
+  if (!read_bytes_result.ok()) {
+    return ByteArray{};
+  }
+
+  return read_bytes_result.GetResult();
+}
+
+}  // namespace nearby
+}  // namespace location