1 files changed, 105 insertions, 0 deletions
diff --git a/third_party/libwebrtc/rtc_base/string_to_number.h b/third_party/libwebrtc/rtc_base/string_to_number.h
new file mode 100644
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--- /dev/null
+++ b/third_party/libwebrtc/rtc_base/string_to_number.h
@@ -0,0 +1,105 @@
+/*
+ *  Copyright 2017 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.
+ */
+
+#ifndef RTC_BASE_STRING_TO_NUMBER_H_
+#define RTC_BASE_STRING_TO_NUMBER_H_
+
+#include <limits>
+#include <string>
+#include <type_traits>
+
+#include "absl/strings/string_view.h"
+#include "absl/types/optional.h"
+
+namespace rtc {
+
+// This file declares a family of functions to parse integers from strings.
+// The standard C library functions either fail to indicate errors (atoi, etc.)
+// or are a hassle to work with (strtol, sscanf, etc.). The standard C++ library
+// functions (std::stoi, etc.) indicate errors by throwing exceptions, which
+// are disabled in WebRTC.
+//
+// Integers are parsed using:
+//   absl::optional<int-type> StringToNumber(absl::string_view str,
+//                                           int base = 10);
+//
+// These functions parse a value from the beginning of a string into one of the
+// fundamental integer types, or returns an empty Optional if parsing
+// failed. Values outside of the range supported by the type will be
+// rejected. The strings must begin with a digit or a minus sign. No leading
+// space nor trailing contents are allowed.
+// By setting base to 0, one of octal, decimal or hexadecimal will be
+// detected from the string's prefix (0, nothing or 0x, respectively).
+// If non-zero, base can be set to a value between 2 and 36 inclusively.
+
+namespace string_to_number_internal {
+// These must be (unsigned) long long, to match the signature of strto(u)ll.
+using unsigned_type = unsigned long long;  // NOLINT(runtime/int)
+using signed_type = long long;             // NOLINT(runtime/int)
+
+absl::optional<signed_type> ParseSigned(absl::string_view str, int base);
+absl::optional<unsigned_type> ParseUnsigned(absl::string_view str, int base);
+
+template <typename T>
+absl::optional<T> ParseFloatingPoint(absl::string_view str);
+}  // namespace string_to_number_internal
+
+template <typename T>
+typename std::enable_if<std::is_integral<T>::value && std::is_signed<T>::value,
+                        absl::optional<T>>::type
+StringToNumber(absl::string_view str, int base = 10) {
+  using string_to_number_internal::signed_type;
+  static_assert(
+      std::numeric_limits<T>::max() <=
+              std::numeric_limits<signed_type>::max() &&
+          std::numeric_limits<T>::lowest() >=
+              std::numeric_limits<signed_type>::lowest(),
+      "StringToNumber only supports signed integers as large as long long int");
+  absl::optional<signed_type> value =
+      string_to_number_internal::ParseSigned(str, base);
+  if (value && *value >= std::numeric_limits<T>::lowest() &&
+      *value <= std::numeric_limits<T>::max()) {
+    return static_cast<T>(*value);
+  }
+  return absl::nullopt;
+}
+
+template <typename T>
+typename std::enable_if<std::is_integral<T>::value &&
+                            std::is_unsigned<T>::value,
+                        absl::optional<T>>::type
+StringToNumber(absl::string_view str, int base = 10) {
+  using string_to_number_internal::unsigned_type;
+  static_assert(std::numeric_limits<T>::max() <=
+                    std::numeric_limits<unsigned_type>::max(),
+                "StringToNumber only supports unsigned integers as large as "
+                "unsigned long long int");
+  absl::optional<unsigned_type> value =
+      string_to_number_internal::ParseUnsigned(str, base);
+  if (value && *value <= std::numeric_limits<T>::max()) {
+    return static_cast<T>(*value);
+  }
+  return absl::nullopt;
+}
+
+template <typename T>
+typename std::enable_if<std::is_floating_point<T>::value,
+                        absl::optional<T>>::type
+StringToNumber(absl::string_view str, int base = 10) {
+  static_assert(
+      std::numeric_limits<T>::max() <= std::numeric_limits<long double>::max(),
+      "StringToNumber only supports floating-point numbers as large "
+      "as long double");
+  return string_to_number_internal::ParseFloatingPoint<T>(str);
+}
+
+}  // namespace rtc
+
+#endif  // RTC_BASE_STRING_TO_NUMBER_H_