EDK: Add functions for converting between strings and numbers.

mojo/edk/util/string_number_conversions.h

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Functions for converting between numbers and their representations as strings
+// (in decimal, in a locale-independent way).
+
+#ifndef MOJO_EDK_UTIL_STRING_NUMBER_CONVERSIONS_H_
+#define MOJO_EDK_UTIL_STRING_NUMBER_CONVERSIONS_H_
+
+#include <string>
+
+namespace mojo {
+namespace util {
+
+// Converts |number| to a string with a locale-independent decimal
+// representation of it. This is available for all |NumberType|s (u)intN_t (from
+// <stdint.h>) and also (unsigned) int.
+template <typename NumberType>
+std::string NumberToString(NumberType number);

[vardhan, 2015/12/02 00:07:42]

is locale the only reason you would want to use this vs. std::to_string<>()?

+
+// Converts |string| containing a locale-independent decimal representation of a
+// number to a numeric representation of that number. (On error, this returns
+// false and leaves |*number| alone.) This is available for all |NumberType|s
+// (u)intN_t (from <stdint.h>) and also (unsigned) int.
+//
+// Notes: Unary '+' is not allowed. Leading zeros are allowed (and ignored). For
+// unsigned types, unary '-' is not allowed. For signed types, "-0", "-00", etc.
+// are also allowed.
+template <typename NumberType>
+bool StringToNumberWithError(const std::string& string, NumberType* number);
+
+// Converts |string| containing a locale-independent decimal representation of a
+// number to a numeric representation of that number. (On error, this returns
+// zero.) This is available for all |NumberType|s (u)intN_t (from <stdint.h>)
+// and also (unsigned) int. (See |StringToNumberWithError()| for more details.)
+template <typename NumberType>
+NumberType StringToNumber(const std::string& string) {
+  NumberType rv = static_cast<NumberType>(0);
+  return StringToNumberWithError(string, &rv) ? rv : static_cast<NumberType>(0);
+}
+
+}  // namespace util
+}  // namespace mojo
+
+#endif  // MOJO_EDK_UTIL_STRING_NUMBER_CONVERSIONS_H_