Add a virtual beamforming audio device on ChromeOS.

media/audio/point.cc

+// Copyright (c) 2015 The Chromium Authors. All rights reserved.

[mcasas, 2015/09/02 03:05:37]

// Copyright 2015,
with no (c)

[ajm, 2015/09/02 06:41:48]

Thanks, copied from an old file.

+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "media/audio/point.h"
+
+#include "base/logging.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/strings/string_split.h"
+#include "base/strings/string_util.h"
+#include "base/strings/stringprintf.h"
+
+namespace media {
+
+Point::Point() : x_(0), y_(0), z_(0){};
+Point::Point(float x, float y, float z) : x_(x), y_(y), z_(z) {}
+
+bool Point::IsValid() const {
+  return std::isfinite(x_) && std::isfinite(y_) && std::isfinite(z_);
+}
+
+std::string Point::ToString() const {
+  return base::StringPrintf("x=%.3f, y=%.3f, z=%.3f", x_, y_, z_);
+}
+
+std::vector<Point> ParsePointsFromString(const std::string& points_string) {
+  std::vector<Point> points;
+  if (points_string.empty()) {

[mcasas, 2015/09/02 03:05:37]

No {}

+    return points;
+  }
+
+  const auto& tokens =
+      base::SplitString(points_string, base::kWhitespaceASCII,
+                        base::KEEP_WHITESPACE, base::SPLIT_WANT_NONEMPTY);
+  if (tokens.size() < 3 || tokens.size() % 3 != 0) {
+    LOG(ERROR) << "Malformed points string: " << points_string;
+    return points;
+  }
+
+  std::vector<float> float_tokens;
+  float_tokens.reserve(tokens.size());

[mcasas, 2015/09/02 03:05:37]

std::vector<float> float_tokens(tokens.size());

[ajm, 2015/09/02 06:41:48]

That will insert tokens.size() default-initialized floats, which is not what I
want.

[mcasas, 2015/09/03 15:29:27]

Actually both are the same, reserve() will also insert stuff
"If case of reallocation, the storage is allocated using the 
container's allocator, "

http://www.cplusplus.com/reference/vector/vector/reserve/

[ajm, 2015/09/03 20:32:04]

They are most certainly not the same. reserve() allocates memory but does not
insert elements. Run this example if you'd like a demonstration:
#include <iostream>
#include <vector>

template <typename T>
void PrintVector(const std::vector<T>& vec) {
  std::cout << "size: " << vec.size() << std::endl;
  std::cout << "elements: ";
  for (const auto& v : vec) {
    std::cout << v << " ";
  }
  std::cout << std::endl;
}

int main() {
  std::cout << "vec_initialized" << std::endl;
  std::vector<int> vec_initialized(10);
  PrintVector(vec_initialized);

  std::cout << std::endl << "vec_reserved" << std::endl;
  std::vector<int> vec_reserved;
  vec_reserved.reserve(10);
  PrintVector(vec_reserved);

  return 0;
}

$ ./a.out
vec_initialized
size: 10
elements: 0 0 0 0 0 0 0 0 0 0

vec_reserved
size: 0
elements:

+  for (const auto& token : tokens) {
+    double float_token;
+    if (!base::StringToDouble(token, &float_token)) {
+      LOG(ERROR) << "Unable to convert token=" << token
+                 << " to double from points string: " << points_string;
+      return points;
+    }
+    float_tokens.push_back(float_token);
+  }
+
+  points.reserve(float_tokens.size() / 3);
+  for (size_t i = 0; i < float_tokens.size(); i += 3) {
+    points.push_back(
+        Point(float_tokens[i + 0], float_tokens[i + 1], float_tokens[i + 2]));
+  }
+
+  return points;
+}
+
+}  // namespace media