Add string_number_conversion and its test

util/stdlib/string_number_conversion.cc

Index: util/stdlib/string_number_conversion.cc
diff --git a/util/stdlib/string_number_conversion.cc b/util/stdlib/string_number_conversion.cc
new file mode 100644
index 0000000000000000000000000000000000000000..76c80fdd5ec179f6b495122f4db9bf7c72e92c6f
--- /dev/null
+++ b/util/stdlib/string_number_conversion.cc
@@ -0,0 +1,157 @@
+// Copyright 2014 The Crashpad Authors. All rights reserved.
+//
+// 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
+//
+//     http://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 "util/stdlib/string_number_conversion.h"
+
+#include <ctype.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <limits>
+
+#include "base/basictypes.h"
+#include "base/logging.h"
+#include "util/stdlib/cxx.h"
+
+// CONSTEXPR_COMPILE_ASSERT will be a normal COMPILE_ASSERT if the C++ library
+// is the C++11 library. If using an older C++ library when compiling C++11
+// code, the std::numeric_limits<>::min() and max() functions will not be
+// marked as constexpr, and thus won’t be usable with C++11’s static_assert().
+// In that case, a run-time CHECK() will have to do.
+#if CXX_LIBRARY_VERSION >= 2011
+#define CONSTEXPR_COMPILE_ASSERT(condition, message) \
+  COMPILE_ASSERT(condition, message)
+#else
+#define CONSTEXPR_COMPILE_ASSERT(condition, message) CHECK(condition)
+#endif
+
+namespace {
+
+template <typename TIntType, typename TLongType>
+struct StringToIntegerTraits {
+  typedef TIntType IntType;
+  typedef TLongType LongType;
+  static void TypeCheck() {
+    COMPILE_ASSERT(std::numeric_limits<TIntType>::is_integer &&
+                       std::numeric_limits<TLongType>::is_integer,
+                   IntType_and_LongType_must_be_integer);
+    COMPILE_ASSERT(std::numeric_limits<TIntType>::is_signed ==
+                       std::numeric_limits<TLongType>::is_signed,
+                   IntType_and_LongType_signedness_must_agree);
+    CONSTEXPR_COMPILE_ASSERT(std::numeric_limits<TIntType>::min() >=
+                                     std::numeric_limits<TLongType>::min() &&
+                                 std::numeric_limits<TIntType>::min() <
+                                     std::numeric_limits<TLongType>::max(),
+                             IntType_min_must_be_in_LongType_range);
+    CONSTEXPR_COMPILE_ASSERT(std::numeric_limits<TIntType>::max() >
+                                     std::numeric_limits<TLongType>::min() &&
+                                 std::numeric_limits<TIntType>::max() <=
+                                     std::numeric_limits<TLongType>::max(),
+                             IntType_max_must_be_in_LongType_range);
+  }
+};
+
+template <typename TIntType, typename TLongType>
+struct StringToSignedIntegerTraits
+    : public StringToIntegerTraits<TIntType, TLongType> {
+  static void TypeCheck() {
+    COMPILE_ASSERT(std::numeric_limits<TIntType>::is_signed,
+                   StringToSignedTraits_IntType_must_be_signed);
+    return super::TypeCheck();
+  }
+  static bool IsNegativeOverflow(TLongType value) {
+    return value < std::numeric_limits<TIntType>::min();
+  }
+
+ private:
+  typedef StringToIntegerTraits<TIntType, TLongType> super;
+};
+
+template <typename TIntType, typename TLongType>
+struct StringToUnsignedIntegerTraits
+    : public StringToIntegerTraits<TIntType, TLongType> {
+  static void TypeCheck() {
+    COMPILE_ASSERT(!std::numeric_limits<TIntType>::is_signed,
+                   StringToUnsignedTraits_IntType_must_be_unsigned);
+    return super::TypeCheck();
+  }
+  static bool IsNegativeOverflow(TLongType value) { return false; }
+
+ private:
+  typedef StringToIntegerTraits<TIntType, TLongType> super;
+};
+
+struct StringToIntTraits : public StringToSignedIntegerTraits<int, long> {
+  static LongType Convert(const char* str, char** end, int base) {
+    return strtol(str, end, base);
+  }
+};
+
+struct StringToUnsignedIntTraits
+    : public StringToUnsignedIntegerTraits<unsigned int, unsigned long> {
+  static LongType Convert(const char* str, char** end, int base) {
+    if (str[0] == '-') {
+      return 0;
+    }
+    return strtoul(str, end, base);
+  }
+};
+
+template <typename Traits>
+bool StringToIntegerInternal(const base::StringPiece& string,
+                             typename Traits::IntType* number) {
+  typedef typename Traits::IntType IntType;
+  typedef typename Traits::LongType LongType;
+
+  Traits::TypeCheck();
+
+  if (string.empty() || isspace(string[0])) {
+    return false;
+  }
+
+  if (string[string.length()] != '\0') {
+    // The implementations use the C standard library’s conversion routines,
+    // which rely on the strings having a trailing NUL character. std::string
+    // will NUL-terminate.
+    std::string terminated_string(string.data(), string.length());
+    return StringToIntegerInternal<Traits>(terminated_string, number);
+  }
+
+  errno = 0;
+  char* end;
+  LongType result = Traits::Convert(string.data(), &end, 0);
+  if (Traits::IsNegativeOverflow(result) ||
+      result > std::numeric_limits<IntType>::max() ||
+      errno == ERANGE ||
+      end != string.data() + string.length()) {
+    return false;
+  }
+  *number = result;
+  return true;
+}
+
+}  // namespace
+
+namespace crashpad {
+
+bool StringToNumber(const base::StringPiece& string, int* number) {
+  return StringToIntegerInternal<StringToIntTraits>(string, number);
+}
+
+bool StringToNumber(const base::StringPiece& string, unsigned int* number) {
+  return StringToIntegerInternal<StringToUnsignedIntTraits>(string, number);
+}
+
+}  // namespace crashpad