add external dependencies in a pre-built way to avoid incompatibilities

external/include/google/protobuf/stubs/stringpiece.h

@@ -0,0 +1,390 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// A StringPiece points to part or all of a string, Cord, double-quoted string
+// literal, or other string-like object.  A StringPiece does *not* own the
+// string to which it points.  A StringPiece is not null-terminated.
+//
+// You can use StringPiece as a function or method parameter.  A StringPiece
+// parameter can receive a double-quoted string literal argument, a "const
+// char*" argument, a string argument, or a StringPiece argument with no data
+// copying.  Systematic use of StringPiece for arguments reduces data
+// copies and strlen() calls.
+//
+// Prefer passing StringPieces by value:
+//   void MyFunction(StringPiece arg);
+// If circumstances require, you may also pass by const reference:
+//   void MyFunction(const StringPiece& arg);  // not preferred
+// Both of these have the same lifetime semantics.  Passing by value
+// generates slightly smaller code.  For more discussion, see the thread
+// go/stringpiecebyvalue on c-users.
+//
+// StringPiece is also suitable for local variables if you know that
+// the lifetime of the underlying object is longer than the lifetime
+// of your StringPiece variable.
+//
+// Beware of binding a StringPiece to a temporary:
+//   StringPiece sp = obj.MethodReturningString();  // BAD: lifetime problem
+//
+// This code is okay:
+//   string str = obj.MethodReturningString();  // str owns its contents
+//   StringPiece sp(str);  // GOOD, because str outlives sp
+//
+// StringPiece is sometimes a poor choice for a return value and usually a poor
+// choice for a data member.  If you do use a StringPiece this way, it is your
+// responsibility to ensure that the object pointed to by the StringPiece
+// outlives the StringPiece.
+//
+// A StringPiece may represent just part of a string; thus the name "Piece".
+// For example, when splitting a string, vector<StringPiece> is a natural data
+// type for the output.  For another example, a Cord is a non-contiguous,
+// potentially very long string-like object.  The Cord class has an interface
+// that iteratively provides StringPiece objects that point to the
+// successive pieces of a Cord object.
+//
+// A StringPiece is not null-terminated.  If you write code that scans a
+// StringPiece, you must check its length before reading any characters.
+// Common idioms that work on null-terminated strings do not work on
+// StringPiece objects.
+//
+// There are several ways to create a null StringPiece:
+//   StringPiece()
+//   StringPiece(nullptr)
+//   StringPiece(nullptr, 0)
+// For all of the above, sp.data() == nullptr, sp.length() == 0,
+// and sp.empty() == true.  Also, if you create a StringPiece with
+// a non-null pointer then sp.data() != nullptr.  Once created,
+// sp.data() will stay either nullptr or not-nullptr, except if you call
+// sp.clear() or sp.set().
+//
+// Thus, you can use StringPiece(nullptr) to signal an out-of-band value
+// that is different from other StringPiece values.  This is similar
+// to the way that const char* p1 = nullptr; is different from
+// const char* p2 = "";.
+//
+// There are many ways to create an empty StringPiece:
+//   StringPiece()
+//   StringPiece(nullptr)
+//   StringPiece(nullptr, 0)
+//   StringPiece("")
+//   StringPiece("", 0)
+//   StringPiece("abcdef", 0)
+//   StringPiece("abcdef"+6, 0)
+// For all of the above, sp.length() will be 0 and sp.empty() will be true.
+// For some empty StringPiece values, sp.data() will be nullptr.
+// For some empty StringPiece values, sp.data() will not be nullptr.
+//
+// Be careful not to confuse: null StringPiece and empty StringPiece.
+// The set of empty StringPieces properly includes the set of null StringPieces.
+// That is, every null StringPiece is an empty StringPiece,
+// but some non-null StringPieces are empty Stringpieces too.
+//
+// All empty StringPiece values compare equal to each other.
+// Even a null StringPieces compares equal to a non-null empty StringPiece:
+//  StringPiece() == StringPiece("", 0)
+//  StringPiece(nullptr) == StringPiece("abc", 0)
+//  StringPiece(nullptr, 0) == StringPiece("abcdef"+6, 0)
+//
+// Look carefully at this example:
+//   StringPiece("") == nullptr
+// True or false?  TRUE, because StringPiece::operator== converts
+// the right-hand side from nullptr to StringPiece(nullptr),
+// and then compares two zero-length spans of characters.
+// However, we are working to make this example produce a compile error.
+//
+// Suppose you want to write:
+//   bool TestWhat?(StringPiece sp) { return sp == nullptr; }  // BAD
+// Do not do that.  Write one of these instead:
+//   bool TestNull(StringPiece sp) { return sp.data() == nullptr; }
+//   bool TestEmpty(StringPiece sp) { return sp.empty(); }
+// The intent of TestWhat? is unclear.  Did you mean TestNull or TestEmpty?
+// Right now, TestWhat? behaves likes TestEmpty.
+// We are working to make TestWhat? produce a compile error.
+// TestNull is good to test for an out-of-band signal.
+// TestEmpty is good to test for an empty StringPiece.
+//
+// Caveats (again):
+// (1) The lifetime of the pointed-to string (or piece of a string)
+//     must be longer than the lifetime of the StringPiece.
+// (2) There may or may not be a '\0' character after the end of
+//     StringPiece data.
+// (3) A null StringPiece is empty.
+//     An empty StringPiece may or may not be a null StringPiece.
+
+#ifndef GOOGLE_PROTOBUF_STUBS_STRINGPIECE_H_
+#define GOOGLE_PROTOBUF_STUBS_STRINGPIECE_H_
+
+#include <assert.h>
+#include <stddef.h>
+#include <string.h>
+#include <iosfwd>
+#include <limits>
+#include <string>
+
+#include <google/protobuf/stubs/hash.h>
+
+#include <google/protobuf/port_def.inc>
+
+namespace google {
+namespace protobuf {
+namespace stringpiece_internal {
+
+class PROTOBUF_EXPORT StringPiece {
+ public:
+  using traits_type = std::char_traits<char>;
+  using value_type = char;
+  using pointer = char*;
+  using const_pointer = const char*;
+  using reference = char&;
+  using const_reference = const char&;
+  using const_iterator = const char*;
+  using iterator = const_iterator;
+  using const_reverse_iterator = std::reverse_iterator<const_iterator>;
+  using reverse_iterator = const_reverse_iterator;
+  using size_type = size_t;
+  using difference_type = std::ptrdiff_t;
+
+ private:
+  const char* ptr_;
+  size_type length_;
+
+  static constexpr size_type kMaxSize =
+      (std::numeric_limits<difference_type>::max)();
+
+  static size_type CheckSize(size_type size) {
+#if !defined(NDEBUG) || defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0
+    if (PROTOBUF_PREDICT_FALSE(size > kMaxSize)) {
+      // Some people grep for this message in logs
+      // so take care if you ever change it.
+      LogFatalSizeTooBig(size, "string length exceeds max size");
+    }
+#endif
+    return size;
+  }
+
+  // Out-of-line error path.
+  static void LogFatalSizeTooBig(size_type size, const char* details);
+
+ public:
+  // We provide non-explicit singleton constructors so users can pass
+  // in a "const char*" or a "string" wherever a "StringPiece" is
+  // expected.
+  //
+  // Style guide exception granted:
+  // http://goto/style-guide-exception-20978288
+  StringPiece() : ptr_(nullptr), length_(0) {}
+
+  StringPiece(const char* str)  // NOLINT(runtime/explicit)
+      : ptr_(str), length_(0) {
+    if (str != nullptr) {
+      length_ = CheckSize(strlen(str));
+    }
+  }
+
+  template <class Allocator>
+  StringPiece(  // NOLINT(runtime/explicit)
+      const std::basic_string<char, std::char_traits<char>, Allocator>& str)
+      : ptr_(str.data()), length_(0) {
+    length_ = CheckSize(str.size());
+  }
+
+  StringPiece(const char* offset, size_type len)
+      : ptr_(offset), length_(CheckSize(len)) {}
+
+  // data() may return a pointer to a buffer with embedded NULs, and the
+  // returned buffer may or may not be null terminated.  Therefore it is
+  // typically a mistake to pass data() to a routine that expects a NUL
+  // terminated string.
+  const_pointer data() const { return ptr_; }
+  size_type size() const { return length_; }
+  size_type length() const { return length_; }
+  bool empty() const { return length_ == 0; }
+
+  char operator[](size_type i) const {
+    assert(i < length_);
+    return ptr_[i];
+  }
+
+  void remove_prefix(size_type n) {
+    assert(length_ >= n);
+    ptr_ += n;
+    length_ -= n;
+  }
+
+  void remove_suffix(size_type n) {
+    assert(length_ >= n);
+    length_ -= n;
+  }
+
+  // returns {-1, 0, 1}
+  int compare(StringPiece x) const {
+    size_type min_size = length_ < x.length_ ? length_ : x.length_;
+    int r = memcmp(ptr_, x.ptr_, static_cast<size_t>(min_size));
+    if (r < 0) return -1;
+    if (r > 0) return 1;
+    if (length_ < x.length_) return -1;
+    if (length_ > x.length_) return 1;
+    return 0;
+  }
+
+  std::string as_string() const { return ToString(); }
+  // We also define ToString() here, since many other string-like
+  // interfaces name the routine that converts to a C++ string
+  // "ToString", and it's confusing to have the method that does that
+  // for a StringPiece be called "as_string()".  We also leave the
+  // "as_string()" method defined here for existing code.
+  std::string ToString() const {
+    if (ptr_ == nullptr) return "";
+    return std::string(data(), static_cast<size_type>(size()));
+  }
+
+  explicit operator std::string() const { return ToString(); }
+
+  void CopyToString(std::string* target) const;
+  void AppendToString(std::string* target) const;
+
+  bool starts_with(StringPiece x) const {
+    return (length_ >= x.length_) &&
+           (memcmp(ptr_, x.ptr_, static_cast<size_t>(x.length_)) == 0);
+  }
+
+  bool ends_with(StringPiece x) const {
+    return ((length_ >= x.length_) &&
+            (memcmp(ptr_ + (length_-x.length_), x.ptr_,
+                 static_cast<size_t>(x.length_)) == 0));
+  }
+
+  // Checks whether StringPiece starts with x and if so advances the beginning
+  // of it to past the match.  It's basically a shortcut for starts_with
+  // followed by remove_prefix.
+  bool Consume(StringPiece x);
+  // Like above but for the end of the string.
+  bool ConsumeFromEnd(StringPiece x);
+
+  // standard STL container boilerplate
+  static const size_type npos;
+  const_iterator begin() const { return ptr_; }
+  const_iterator end() const { return ptr_ + length_; }
+  const_reverse_iterator rbegin() const {
+    return const_reverse_iterator(ptr_ + length_);
+  }
+  const_reverse_iterator rend() const {
+    return const_reverse_iterator(ptr_);
+  }
+  size_type max_size() const { return length_; }
+  size_type capacity() const { return length_; }
+
+  // cpplint.py emits a false positive [build/include_what_you_use]
+  size_type copy(char* buf, size_type n, size_type pos = 0) const;  // NOLINT
+
+  bool contains(StringPiece s) const;
+
+  size_type find(StringPiece s, size_type pos = 0) const;
+  size_type find(char c, size_type pos = 0) const;
+  size_type rfind(StringPiece s, size_type pos = npos) const;
+  size_type rfind(char c, size_type pos = npos) const;
+
+  size_type find_first_of(StringPiece s, size_type pos = 0) const;
+  size_type find_first_of(char c, size_type pos = 0) const {
+    return find(c, pos);
+  }
+  size_type find_first_not_of(StringPiece s, size_type pos = 0) const;
+  size_type find_first_not_of(char c, size_type pos = 0) const;
+  size_type find_last_of(StringPiece s, size_type pos = npos) const;
+  size_type find_last_of(char c, size_type pos = npos) const {
+    return rfind(c, pos);
+  }
+  size_type find_last_not_of(StringPiece s, size_type pos = npos) const;
+  size_type find_last_not_of(char c, size_type pos = npos) const;
+
+  StringPiece substr(size_type pos, size_type n = npos) const;
+};
+
+// This large function is defined inline so that in a fairly common case where
+// one of the arguments is a literal, the compiler can elide a lot of the
+// following comparisons.
+inline bool operator==(StringPiece x, StringPiece y) {
+  StringPiece::size_type len = x.size();
+  if (len != y.size()) {
+    return false;
+  }
+
+  return x.data() == y.data() || len <= 0 ||
+      memcmp(x.data(), y.data(), static_cast<size_t>(len)) == 0;
+}
+
+inline bool operator!=(StringPiece x, StringPiece y) {
+  return !(x == y);
+}
+
+inline bool operator<(StringPiece x, StringPiece y) {
+  const StringPiece::size_type min_size =
+      x.size() < y.size() ? x.size() : y.size();
+  const int r = memcmp(x.data(), y.data(), static_cast<size_t>(min_size));
+  return (r < 0) || (r == 0 && x.size() < y.size());
+}
+
+inline bool operator>(StringPiece x, StringPiece y) {
+  return y < x;
+}
+
+inline bool operator<=(StringPiece x, StringPiece y) {
+  return !(x > y);
+}
+
+inline bool operator>=(StringPiece x, StringPiece y) {
+  return !(x < y);
+}
+
+// allow StringPiece to be logged
+extern std::ostream& operator<<(std::ostream& o, StringPiece piece);
+
+}  // namespace stringpiece_internal
+
+using ::google::protobuf::stringpiece_internal::StringPiece;
+
+}  // namespace protobuf
+}  // namespace google
+
+GOOGLE_PROTOBUF_HASH_NAMESPACE_DECLARATION_START
+template<> struct hash<StringPiece> {
+  size_t operator()(const StringPiece& s) const {
+    size_t result = 0;
+    for (const char *str = s.data(), *end = str + s.size(); str < end; str++) {
+      result = 5 * result + static_cast<size_t>(*str);
+    }
+    return result;
+  }
+};
+GOOGLE_PROTOBUF_HASH_NAMESPACE_DECLARATION_END
+
+#include <google/protobuf/port_undef.inc>
+
+#endif  // STRINGS_STRINGPIECE_H_