Move MemoryStream to separate source files, and to a test target.

Also delete the base class MemoryStreamBase.

Bug: webrtc:6424
Change-Id: I7eec40ecff17c7c65fdf55882bccb2abaf1d5d84
Reviewed-on: https://webrtc-review.googlesource.com/c/108622
Commit-Queue: Niels Moller <nisse@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#25494}

rtc_base/memory_stream.cc

@@ -0,0 +1,143 @@
+/*
+ *  Copyright 2018 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include <algorithm>
+
+#include "rtc_base/memory_stream.h"
+
+namespace rtc {
+
+StreamState MemoryStream::GetState() const {
+  return SS_OPEN;
+}
+
+StreamResult MemoryStream::Read(void* buffer,
+                                size_t bytes,
+                                size_t* bytes_read,
+                                int* error) {
+  if (seek_position_ >= data_length_) {
+    return SR_EOS;
+  }
+  size_t available = data_length_ - seek_position_;
+  if (bytes > available) {
+    // Read partial buffer
+    bytes = available;
+  }
+  memcpy(buffer, &buffer_[seek_position_], bytes);
+  seek_position_ += bytes;
+  if (bytes_read) {
+    *bytes_read = bytes;
+  }
+  return SR_SUCCESS;
+}
+
+StreamResult MemoryStream::Write(const void* buffer,
+                                 size_t bytes,
+                                 size_t* bytes_written,
+                                 int* error) {
+  size_t available = buffer_length_ - seek_position_;
+  if (0 == available) {
+    // Increase buffer size to the larger of:
+    // a) new position rounded up to next 256 bytes
+    // b) double the previous length
+    size_t new_buffer_length =
+        std::max(((seek_position_ + bytes) | 0xFF) + 1, buffer_length_ * 2);
+    StreamResult result = DoReserve(new_buffer_length, error);
+    if (SR_SUCCESS != result) {
+      return result;
+    }
+    RTC_DCHECK(buffer_length_ >= new_buffer_length);
+    available = buffer_length_ - seek_position_;
+  }
+
+  if (bytes > available) {
+    bytes = available;
+  }
+  memcpy(&buffer_[seek_position_], buffer, bytes);
+  seek_position_ += bytes;
+  if (data_length_ < seek_position_) {
+    data_length_ = seek_position_;
+  }
+  if (bytes_written) {
+    *bytes_written = bytes;
+  }
+  return SR_SUCCESS;
+}
+
+void MemoryStream::Close() {
+  // nothing to do
+}
+
+bool MemoryStream::SetPosition(size_t position) {
+  if (position > data_length_)
+    return false;
+  seek_position_ = position;
+  return true;
+}
+
+bool MemoryStream::GetPosition(size_t* position) const {
+  if (position)
+    *position = seek_position_;
+  return true;
+}
+
+bool MemoryStream::GetSize(size_t* size) const {
+  if (size)
+    *size = data_length_;
+  return true;
+}
+
+bool MemoryStream::ReserveSize(size_t size) {
+  return (SR_SUCCESS == DoReserve(size, nullptr));
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+MemoryStream::MemoryStream() {}
+
+MemoryStream::MemoryStream(const char* data) {
+  SetData(data, strlen(data));
+}
+
+MemoryStream::MemoryStream(const void* data, size_t length) {
+  SetData(data, length);
+}
+
+MemoryStream::~MemoryStream() {
+  delete[] buffer_;
+}
+
+void MemoryStream::SetData(const void* data, size_t length) {
+  data_length_ = buffer_length_ = length;
+  delete[] buffer_;
+  buffer_ = new char[buffer_length_];
+  memcpy(buffer_, data, data_length_);
+  seek_position_ = 0;
+}
+
+StreamResult MemoryStream::DoReserve(size_t size, int* error) {
+  if (buffer_length_ >= size)
+    return SR_SUCCESS;
+
+  if (char* new_buffer = new char[size]) {
+    memcpy(new_buffer, buffer_, data_length_);
+    delete[] buffer_;
+    buffer_ = new_buffer;
+    buffer_length_ = size;
+    return SR_SUCCESS;
+  }
+
+  if (error) {
+    *error = ENOMEM;
+  }
+  return SR_ERROR;
+}
+
+}  // namespace rtc