1 files changed, 191 insertions, 0 deletions
diff --git a/absl/flags/marshalling.cc b/absl/flags/marshalling.cc
new file mode 100644
index 00000000..71b01d77
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+++ b/absl/flags/marshalling.cc
@@ -0,0 +1,191 @@
+//
+//  Copyright 2019 The Abseil Authors.
+//
+// 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
+//
+//      https://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 "absl/flags/marshalling.h"
+
+#include <limits>
+
+#include "absl/base/macros.h"
+#include "absl/strings/match.h"
+#include "absl/strings/numbers.h"
+#include "absl/strings/str_cat.h"
+#include "absl/strings/str_format.h"
+#include "absl/strings/str_join.h"
+#include "absl/strings/str_split.h"
+
+namespace absl {
+inline namespace lts_2019_08_08 {
+namespace flags_internal {
+
+// --------------------------------------------------------------------
+// AbslParseFlag specializations for boolean type.
+
+bool AbslParseFlag(absl::string_view text, bool* dst, std::string*) {
+  const char* kTrue[] = {"1", "t", "true", "y", "yes"};
+  const char* kFalse[] = {"0", "f", "false", "n", "no"};
+  static_assert(sizeof(kTrue) == sizeof(kFalse), "true_false_equal");
+
+  text = absl::StripAsciiWhitespace(text);
+
+  for (size_t i = 0; i < ABSL_ARRAYSIZE(kTrue); ++i) {
+    if (absl::EqualsIgnoreCase(text, kTrue[i])) {
+      *dst = true;
+      return true;
+    } else if (absl::EqualsIgnoreCase(text, kFalse[i])) {
+      *dst = false;
+      return true;
+    }
+  }
+  return false;  // didn't match a legal input
+}
+
+// --------------------------------------------------------------------
+// AbslParseFlag for integral types.
+
+// Return the base to use for parsing text as an integer.  Leading 0x
+// puts us in base 16.  But leading 0 does not put us in base 8. It
+// caused too many bugs when we had that behavior.
+static int NumericBase(absl::string_view text) {
+  const bool hex = (text.size() >= 2 && text[0] == '0' &&
+                    (text[1] == 'x' || text[1] == 'X'));
+  return hex ? 16 : 10;
+}
+
+template <typename IntType>
+inline bool ParseFlagImpl(absl::string_view text, IntType* dst) {
+  text = absl::StripAsciiWhitespace(text);
+
+  return absl::numbers_internal::safe_strtoi_base(text, dst, NumericBase(text));
+}
+
+bool AbslParseFlag(absl::string_view text, short* dst, std::string*) {
+  int val;
+  if (!ParseFlagImpl(text, &val)) return false;
+  if (static_cast<short>(val) != val)  // worked, but number out of range
+    return false;
+  *dst = static_cast<short>(val);
+  return true;
+}
+
+bool AbslParseFlag(absl::string_view text, unsigned short* dst, std::string*) {
+  unsigned int val;
+  if (!ParseFlagImpl(text, &val)) return false;
+  if (static_cast<unsigned short>(val) !=
+      val)  // worked, but number out of range
+    return false;
+  *dst = static_cast<unsigned short>(val);
+  return true;
+}
+
+bool AbslParseFlag(absl::string_view text, int* dst, std::string*) {
+  return ParseFlagImpl(text, dst);
+}
+
+bool AbslParseFlag(absl::string_view text, unsigned int* dst, std::string*) {
+  return ParseFlagImpl(text, dst);
+}
+
+bool AbslParseFlag(absl::string_view text, long* dst, std::string*) {
+  return ParseFlagImpl(text, dst);
+}
+
+bool AbslParseFlag(absl::string_view text, unsigned long* dst, std::string*) {
+  return ParseFlagImpl(text, dst);
+}
+
+bool AbslParseFlag(absl::string_view text, long long* dst, std::string*) {
+  return ParseFlagImpl(text, dst);
+}
+
+bool AbslParseFlag(absl::string_view text, unsigned long long* dst,
+                   std::string*) {
+  return ParseFlagImpl(text, dst);
+}
+
+// --------------------------------------------------------------------
+// AbslParseFlag for floating point types.
+
+bool AbslParseFlag(absl::string_view text, float* dst, std::string*) {
+  return absl::SimpleAtof(text, dst);
+}
+
+bool AbslParseFlag(absl::string_view text, double* dst, std::string*) {
+  return absl::SimpleAtod(text, dst);
+}
+
+// --------------------------------------------------------------------
+// AbslParseFlag for strings.
+
+bool AbslParseFlag(absl::string_view text, std::string* dst, std::string*) {
+  dst->assign(text.data(), text.size());
+  return true;
+}
+
+// --------------------------------------------------------------------
+// AbslParseFlag for vector of strings.
+
+bool AbslParseFlag(absl::string_view text, std::vector<std::string>* dst,
+                   std::string*) {
+  // An empty flag value corresponds to an empty vector, not a vector
+  // with a single, empty std::string.
+  if (text.empty()) {
+    dst->clear();
+    return true;
+  }
+  *dst = absl::StrSplit(text, ',', absl::AllowEmpty());
+  return true;
+}
+
+// --------------------------------------------------------------------
+// AbslUnparseFlag specializations for various builtin flag types.
+
+std::string Unparse(bool v) { return v ? "true" : "false"; }
+std::string Unparse(short v) { return absl::StrCat(v); }
+std::string Unparse(unsigned short v) { return absl::StrCat(v); }
+std::string Unparse(int v) { return absl::StrCat(v); }
+std::string Unparse(unsigned int v) { return absl::StrCat(v); }
+std::string Unparse(long v) { return absl::StrCat(v); }
+std::string Unparse(unsigned long v) { return absl::StrCat(v); }
+std::string Unparse(long long v) { return absl::StrCat(v); }
+std::string Unparse(unsigned long long v) { return absl::StrCat(v); }
+template <typename T>
+std::string UnparseFloatingPointVal(T v) {
+  // digits10 is guaranteed to roundtrip correctly in std::string -> value -> std::string
+  // conversions, but may not be enough to represent all the values correctly.
+  std::string digit10_str =
+      absl::StrFormat("%.*g", std::numeric_limits<T>::digits10, v);
+  if (std::isnan(v) || std::isinf(v)) return digit10_str;
+
+  T roundtrip_val = 0;
+  std::string err;
+  if (absl::ParseFlag(digit10_str, &roundtrip_val, &err) &&
+      roundtrip_val == v) {
+    return digit10_str;
+  }
+
+  // max_digits10 is the number of base-10 digits that are necessary to uniquely
+  // represent all distinct values.
+  return absl::StrFormat("%.*g", std::numeric_limits<T>::max_digits10, v);
+}
+std::string Unparse(float v) { return UnparseFloatingPointVal(v); }
+std::string Unparse(double v) { return UnparseFloatingPointVal(v); }
+std::string AbslUnparseFlag(absl::string_view v) { return std::string(v); }
+std::string AbslUnparseFlag(const std::vector<std::string>& v) {
+  return absl::StrJoin(v, ",");
+}
+
+}  // namespace flags_internal
+}  // inline namespace lts_2019_08_08
+}  // namespace absl