http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/strings/string_view_test.cc
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+// Copyright 2017 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
+//
+//      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 "absl/strings/string_view.h"
+
+#include <stdlib.h>
+#include <iomanip>
+#include <iterator>
+#include <limits>
+#include <map>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+#include <type_traits>
+#include <utility>
+
+#include "gtest/gtest.h"
+#include "absl/base/config.h"
+#include "absl/base/dynamic_annotations.h"
+
+namespace {
+
+// A minimal allocator that uses malloc().
+template <typename T>
+struct Mallocator {
+  typedef T value_type;
+  typedef size_t size_type;
+  typedef ptrdiff_t difference_type;
+  typedef T* pointer;
+  typedef const T* const_pointer;
+  typedef T& reference;
+  typedef const T& const_reference;
+
+  size_type max_size() const {
+    return size_t(std::numeric_limits<size_type>::max()) / sizeof(value_type);
+  }
+  template <typename U>
+  struct rebind {
+    typedef Mallocator<U> other;
+  };
+  Mallocator() = default;
+  template <class U>
+  Mallocator(const Mallocator<U>&) {}  // NOLINT(runtime/explicit)
+
+  T* allocate(size_t n) { return static_cast<T*>(std::malloc(n * sizeof(T))); }
+  void deallocate(T* p, size_t) { std::free(p); }
+};
+template <typename T, typename U>
+bool operator==(const Mallocator<T>&, const Mallocator<U>&) {
+  return true;
+}
+template <typename T, typename U>
+bool operator!=(const Mallocator<T>&, const Mallocator<U>&) {
+  return false;
+}
+
+TEST(StringViewTest, Ctor) {
+  {
+    // Null.
+    absl::string_view s10;
+    EXPECT_TRUE(s10.data() == nullptr);
+    EXPECT_EQ(0, s10.length());
+  }
+
+  {
+    // const char* without length.
+    const char* hello = "hello";
+    absl::string_view s20(hello);
+    EXPECT_TRUE(s20.data() == hello);
+    EXPECT_EQ(5, s20.length());
+
+    // const char* with length.
+    absl::string_view s21(hello, 4);
+    EXPECT_TRUE(s21.data() == hello);
+    EXPECT_EQ(4, s21.length());
+
+    // Not recommended, but valid C++
+    absl::string_view s22(hello, 6);
+    EXPECT_TRUE(s22.data() == hello);
+    EXPECT_EQ(6, s22.length());
+  }
+
+  {
+    // std::string.
+    std::string hola = "hola";
+    absl::string_view s30(hola);
+    EXPECT_TRUE(s30.data() == hola.data());
+    EXPECT_EQ(4, s30.length());
+
+    // std::string with embedded '\0'.
+    hola.push_back('\0');
+    hola.append("h2");
+    hola.push_back('\0');
+    absl::string_view s31(hola);
+    EXPECT_TRUE(s31.data() == hola.data());
+    EXPECT_EQ(8, s31.length());
+  }
+
+  {
+    using mstring =
+        std::basic_string<char, std::char_traits<char>, Mallocator<char>>;
+    mstring str1("BUNGIE-JUMPING!");
+    const mstring str2("SLEEPING!");
+
+    absl::string_view s1(str1);
+    s1.remove_prefix(strlen("BUNGIE-JUM"));
+
+    absl::string_view s2(str2);
+    s2.remove_prefix(strlen("SLEE"));
+
+    EXPECT_EQ(s1, s2);
+    EXPECT_EQ(s1, "PING!");
+  }
+
+  // TODO(mec): absl::string_view(const absl::string_view&);
+}
+
+TEST(StringViewTest, Swap) {
+  absl::string_view a("a");
+  absl::string_view b("bbb");
+  EXPECT_TRUE(noexcept(a.swap(b)));
+  a.swap(b);
+  EXPECT_EQ(a, "bbb");
+  EXPECT_EQ(b, "a");
+  a.swap(b);
+  EXPECT_EQ(a, "a");
+  EXPECT_EQ(b, "bbb");
+}
+
+TEST(StringViewTest, STLComparator) {
+  std::string s1("foo");
+  std::string s2("bar");
+  std::string s3("baz");
+
+  absl::string_view p1(s1);
+  absl::string_view p2(s2);
+  absl::string_view p3(s3);
+
+  typedef std::map<absl::string_view, int> TestMap;
+  TestMap map;
+
+  map.insert(std::make_pair(p1, 0));
+  map.insert(std::make_pair(p2, 1));
+  map.insert(std::make_pair(p3, 2));
+  EXPECT_EQ(map.size(), 3);
+
+  TestMap::const_iterator iter = map.begin();
+  EXPECT_EQ(iter->second, 1);
+  ++iter;
+  EXPECT_EQ(iter->second, 2);
+  ++iter;
+  EXPECT_EQ(iter->second, 0);
+  ++iter;
+  EXPECT_TRUE(iter == map.end());
+
+  TestMap::iterator new_iter = map.find("zot");
+  EXPECT_TRUE(new_iter == map.end());
+
+  new_iter = map.find("bar");
+  EXPECT_TRUE(new_iter != map.end());
+
+  map.erase(new_iter);
+  EXPECT_EQ(map.size(), 2);
+
+  iter = map.begin();
+  EXPECT_EQ(iter->second, 2);
+  ++iter;
+  EXPECT_EQ(iter->second, 0);
+  ++iter;
+  EXPECT_TRUE(iter == map.end());
+}
+
+#define COMPARE(result, op, x, y)                                      \
+  EXPECT_EQ(result, absl::string_view((x)) op absl::string_view((y))); \
+  EXPECT_EQ(result, absl::string_view((x)).compare(absl::string_view((y))) op 
0)
+
+TEST(StringViewTest, ComparisonOperators) {
+  COMPARE(true, ==, "",   "");
+  COMPARE(true, ==, "", absl::string_view());
+  COMPARE(true, ==, absl::string_view(), "");
+  COMPARE(true, ==, "a",  "a");
+  COMPARE(true, ==, "aa", "aa");
+  COMPARE(false, ==, "a",  "");
+  COMPARE(false, ==, "",   "a");
+  COMPARE(false, ==, "a",  "b");
+  COMPARE(false, ==, "a",  "aa");
+  COMPARE(false, ==, "aa", "a");
+
+  COMPARE(false, !=, "",   "");
+  COMPARE(false, !=, "a",  "a");
+  COMPARE(false, !=, "aa", "aa");
+  COMPARE(true, !=, "a",  "");
+  COMPARE(true, !=, "",   "a");
+  COMPARE(true, !=, "a",  "b");
+  COMPARE(true, !=, "a",  "aa");
+  COMPARE(true, !=, "aa", "a");
+
+  COMPARE(true, <, "a",  "b");
+  COMPARE(true, <, "a",  "aa");
+  COMPARE(true, <, "aa", "b");
+  COMPARE(true, <, "aa", "bb");
+  COMPARE(false, <, "a",  "a");
+  COMPARE(false, <, "b",  "a");
+  COMPARE(false, <, "aa", "a");
+  COMPARE(false, <, "b",  "aa");
+  COMPARE(false, <, "bb", "aa");
+
+  COMPARE(true, <=, "a",  "a");
+  COMPARE(true, <=, "a",  "b");
+  COMPARE(true, <=, "a",  "aa");
+  COMPARE(true, <=, "aa", "b");
+  COMPARE(true, <=, "aa", "bb");
+  COMPARE(false, <=, "b",  "a");
+  COMPARE(false, <=, "aa", "a");
+  COMPARE(false, <=, "b",  "aa");
+  COMPARE(false, <=, "bb", "aa");
+
+  COMPARE(false, >=, "a",  "b");
+  COMPARE(false, >=, "a",  "aa");
+  COMPARE(false, >=, "aa", "b");
+  COMPARE(false, >=, "aa", "bb");
+  COMPARE(true, >=, "a",  "a");
+  COMPARE(true, >=, "b",  "a");
+  COMPARE(true, >=, "aa", "a");
+  COMPARE(true, >=, "b",  "aa");
+  COMPARE(true, >=, "bb", "aa");
+
+  COMPARE(false, >, "a",  "a");
+  COMPARE(false, >, "a",  "b");
+  COMPARE(false, >, "a",  "aa");
+  COMPARE(false, >, "aa", "b");
+  COMPARE(false, >, "aa", "bb");
+  COMPARE(true, >, "b",  "a");
+  COMPARE(true, >, "aa", "a");
+  COMPARE(true, >, "b",  "aa");
+  COMPARE(true, >, "bb", "aa");
+}
+
+TEST(StringViewTest, ComparisonOperatorsByCharacterPosition) {
+  std::string x;
+  for (int i = 0; i < 256; i++) {
+    x += 'a';
+    std::string y = x;
+    COMPARE(true, ==, x, y);
+    for (int j = 0; j < i; j++) {
+      std::string z = x;
+      z[j] = 'b';       // Differs in position 'j'
+      COMPARE(false, ==, x, z);
+      COMPARE(true, <, x, z);
+      COMPARE(true, >, z, x);
+      if (j + 1 < i) {
+        z[j + 1] = 'A';  // Differs in position 'j+1' as well
+        COMPARE(false, ==, x, z);
+        COMPARE(true, <, x, z);
+        COMPARE(true, >, z, x);
+        z[j + 1] = 'z';  // Differs in position 'j+1' as well
+        COMPARE(false, ==, x, z);
+        COMPARE(true, <, x, z);
+        COMPARE(true, >, z, x);
+      }
+    }
+  }
+}
+#undef COMPARE
+
+// Sadly, our users often confuse std::string::npos with 
absl::string_view::npos;
+// So much so that we test here that they are the same.  They need to
+// both be unsigned, and both be the maximum-valued integer of their type.
+
+template <typename T>
+struct is_type {
+  template <typename U>
+  static bool same(U) {
+    return false;
+  }
+  static bool same(T) { return true; }
+};
+
+TEST(StringViewTest, NposMatchesStdStringView) {
+  EXPECT_EQ(absl::string_view::npos, std::string::npos);
+
+  EXPECT_TRUE(is_type<size_t>::same(absl::string_view::npos));
+  EXPECT_FALSE(is_type<size_t>::same(""));
+
+  // Make sure absl::string_view::npos continues to be a header constant.
+  char test[absl::string_view::npos & 1] = {0};
+  EXPECT_EQ(0, test[0]);
+}
+
+TEST(StringViewTest, STL1) {
+  const absl::string_view a("abcdefghijklmnopqrstuvwxyz");
+  const absl::string_view b("abc");
+  const absl::string_view c("xyz");
+  const absl::string_view d("foobar");
+  const absl::string_view e;
+  std::string temp("123");
+  temp += '\0';
+  temp += "456";
+  const absl::string_view f(temp);
+
+  EXPECT_EQ(a[6], 'g');
+  EXPECT_EQ(b[0], 'a');
+  EXPECT_EQ(c[2], 'z');
+  EXPECT_EQ(f[3], '\0');
+  EXPECT_EQ(f[5], '5');
+
+  EXPECT_EQ(*d.data(), 'f');
+  EXPECT_EQ(d.data()[5], 'r');
+  EXPECT_TRUE(e.data() == nullptr);
+
+  EXPECT_EQ(*a.begin(), 'a');
+  EXPECT_EQ(*(b.begin() + 2), 'c');
+  EXPECT_EQ(*(c.end() - 1), 'z');
+
+  EXPECT_EQ(*a.rbegin(), 'z');
+  EXPECT_EQ(*(b.rbegin() + 2), 'a');
+  EXPECT_EQ(*(c.rend() - 1), 'x');
+  EXPECT_TRUE(a.rbegin() + 26 == a.rend());
+
+  EXPECT_EQ(a.size(), 26);
+  EXPECT_EQ(b.size(), 3);
+  EXPECT_EQ(c.size(), 3);
+  EXPECT_EQ(d.size(), 6);
+  EXPECT_EQ(e.size(), 0);
+  EXPECT_EQ(f.size(), 7);
+
+  EXPECT_TRUE(!d.empty());
+  EXPECT_TRUE(d.begin() != d.end());
+  EXPECT_TRUE(d.begin() + 6 == d.end());
+
+  EXPECT_TRUE(e.empty());
+  EXPECT_TRUE(e.begin() == e.end());
+
+  char buf[4] = { '%', '%', '%', '%' };
+  EXPECT_EQ(a.copy(buf, 4), 4);
+  EXPECT_EQ(buf[0], a[0]);
+  EXPECT_EQ(buf[1], a[1]);
+  EXPECT_EQ(buf[2], a[2]);
+  EXPECT_EQ(buf[3], a[3]);
+  EXPECT_EQ(a.copy(buf, 3, 7), 3);
+  EXPECT_EQ(buf[0], a[7]);
+  EXPECT_EQ(buf[1], a[8]);
+  EXPECT_EQ(buf[2], a[9]);
+  EXPECT_EQ(buf[3], a[3]);
+  EXPECT_EQ(c.copy(buf, 99), 3);
+  EXPECT_EQ(buf[0], c[0]);
+  EXPECT_EQ(buf[1], c[1]);
+  EXPECT_EQ(buf[2], c[2]);
+  EXPECT_EQ(buf[3], a[3]);
+}
+
+// Separated from STL1() because some compilers produce an overly
+// large stack frame for the combined function.
+TEST(StringViewTest, STL2) {
+  const absl::string_view a("abcdefghijklmnopqrstuvwxyz");
+  const absl::string_view b("abc");
+  const absl::string_view c("xyz");
+  absl::string_view d("foobar");
+  const absl::string_view e;
+  const absl::string_view f(
+      "123"
+      "\0"
+      "456",
+      7);
+
+  d = absl::string_view();
+  EXPECT_EQ(d.size(), 0);
+  EXPECT_TRUE(d.empty());
+  EXPECT_TRUE(d.data() == nullptr);
+  EXPECT_TRUE(d.begin() == d.end());
+
+  EXPECT_EQ(a.find(b), 0);
+  EXPECT_EQ(a.find(b, 1), absl::string_view::npos);
+  EXPECT_EQ(a.find(c), 23);
+  EXPECT_EQ(a.find(c, 9), 23);
+  EXPECT_EQ(a.find(c, absl::string_view::npos), absl::string_view::npos);
+  EXPECT_EQ(b.find(c), absl::string_view::npos);
+  EXPECT_EQ(b.find(c, absl::string_view::npos), absl::string_view::npos);
+  EXPECT_EQ(a.find(d), 0);
+  EXPECT_EQ(a.find(e), 0);
+  EXPECT_EQ(a.find(d, 12), 12);
+  EXPECT_EQ(a.find(e, 17), 17);
+  absl::string_view g("xx not found bb");
+  EXPECT_EQ(a.find(g), absl::string_view::npos);
+  // empty std::string nonsense
+  EXPECT_EQ(d.find(b), absl::string_view::npos);
+  EXPECT_EQ(e.find(b), absl::string_view::npos);
+  EXPECT_EQ(d.find(b, 4), absl::string_view::npos);
+  EXPECT_EQ(e.find(b, 7), absl::string_view::npos);
+
+  size_t empty_search_pos = std::string().find(std::string());
+  EXPECT_EQ(d.find(d), empty_search_pos);
+  EXPECT_EQ(d.find(e), empty_search_pos);
+  EXPECT_EQ(e.find(d), empty_search_pos);
+  EXPECT_EQ(e.find(e), empty_search_pos);
+  EXPECT_EQ(d.find(d, 4), std::string().find(std::string(), 4));
+  EXPECT_EQ(d.find(e, 4), std::string().find(std::string(), 4));
+  EXPECT_EQ(e.find(d, 4), std::string().find(std::string(), 4));
+  EXPECT_EQ(e.find(e, 4), std::string().find(std::string(), 4));
+
+  EXPECT_EQ(a.find('a'), 0);
+  EXPECT_EQ(a.find('c'), 2);
+  EXPECT_EQ(a.find('z'), 25);
+  EXPECT_EQ(a.find('$'), absl::string_view::npos);
+  EXPECT_EQ(a.find('\0'), absl::string_view::npos);
+  EXPECT_EQ(f.find('\0'), 3);
+  EXPECT_EQ(f.find('3'), 2);
+  EXPECT_EQ(f.find('5'), 5);
+  EXPECT_EQ(g.find('o'), 4);
+  EXPECT_EQ(g.find('o', 4), 4);
+  EXPECT_EQ(g.find('o', 5), 8);
+  EXPECT_EQ(a.find('b', 5), absl::string_view::npos);
+  // empty std::string nonsense
+  EXPECT_EQ(d.find('\0'), absl::string_view::npos);
+  EXPECT_EQ(e.find('\0'), absl::string_view::npos);
+  EXPECT_EQ(d.find('\0', 4), absl::string_view::npos);
+  EXPECT_EQ(e.find('\0', 7), absl::string_view::npos);
+  EXPECT_EQ(d.find('x'), absl::string_view::npos);
+  EXPECT_EQ(e.find('x'), absl::string_view::npos);
+  EXPECT_EQ(d.find('x', 4), absl::string_view::npos);
+  EXPECT_EQ(e.find('x', 7), absl::string_view::npos);
+
+  EXPECT_EQ(a.rfind(b), 0);
+  EXPECT_EQ(a.rfind(b, 1), 0);
+  EXPECT_EQ(a.rfind(c), 23);
+  EXPECT_EQ(a.rfind(c, 22), absl::string_view::npos);
+  EXPECT_EQ(a.rfind(c, 1), absl::string_view::npos);
+  EXPECT_EQ(a.rfind(c, 0), absl::string_view::npos);
+  EXPECT_EQ(b.rfind(c), absl::string_view::npos);
+  EXPECT_EQ(b.rfind(c, 0), absl::string_view::npos);
+  EXPECT_EQ(a.rfind(d), std::string(a).rfind(std::string()));
+  EXPECT_EQ(a.rfind(e), std::string(a).rfind(std::string()));
+  EXPECT_EQ(a.rfind(d, 12), 12);
+  EXPECT_EQ(a.rfind(e, 17), 17);
+  EXPECT_EQ(a.rfind(g), absl::string_view::npos);
+  EXPECT_EQ(d.rfind(b), absl::string_view::npos);
+  EXPECT_EQ(e.rfind(b), absl::string_view::npos);
+  EXPECT_EQ(d.rfind(b, 4), absl::string_view::npos);
+  EXPECT_EQ(e.rfind(b, 7), absl::string_view::npos);
+  // empty std::string nonsense
+  EXPECT_EQ(d.rfind(d, 4), std::string().rfind(std::string()));
+  EXPECT_EQ(e.rfind(d, 7), std::string().rfind(std::string()));
+  EXPECT_EQ(d.rfind(e, 4), std::string().rfind(std::string()));
+  EXPECT_EQ(e.rfind(e, 7), std::string().rfind(std::string()));
+  EXPECT_EQ(d.rfind(d), std::string().rfind(std::string()));
+  EXPECT_EQ(e.rfind(d), std::string().rfind(std::string()));
+  EXPECT_EQ(d.rfind(e), std::string().rfind(std::string()));
+  EXPECT_EQ(e.rfind(e), std::string().rfind(std::string()));
+
+  EXPECT_EQ(g.rfind('o'), 8);
+  EXPECT_EQ(g.rfind('q'), absl::string_view::npos);
+  EXPECT_EQ(g.rfind('o', 8), 8);
+  EXPECT_EQ(g.rfind('o', 7), 4);
+  EXPECT_EQ(g.rfind('o', 3), absl::string_view::npos);
+  EXPECT_EQ(f.rfind('\0'), 3);
+  EXPECT_EQ(f.rfind('\0', 12), 3);
+  EXPECT_EQ(f.rfind('3'), 2);
+  EXPECT_EQ(f.rfind('5'), 5);
+  // empty std::string nonsense
+  EXPECT_EQ(d.rfind('o'), absl::string_view::npos);
+  EXPECT_EQ(e.rfind('o'), absl::string_view::npos);
+  EXPECT_EQ(d.rfind('o', 4), absl::string_view::npos);
+  EXPECT_EQ(e.rfind('o', 7), absl::string_view::npos);
+}
+
+// Continued from STL2
+TEST(StringViewTest, STL2FindFirst) {
+  const absl::string_view a("abcdefghijklmnopqrstuvwxyz");
+  const absl::string_view b("abc");
+  const absl::string_view c("xyz");
+  absl::string_view d("foobar");
+  const absl::string_view e;
+  const absl::string_view f(
+      "123"
+      "\0"
+      "456",
+      7);
+  absl::string_view g("xx not found bb");
+
+  d = absl::string_view();
+  EXPECT_EQ(a.find_first_of(b), 0);
+  EXPECT_EQ(a.find_first_of(b, 0), 0);
+  EXPECT_EQ(a.find_first_of(b, 1), 1);
+  EXPECT_EQ(a.find_first_of(b, 2), 2);
+  EXPECT_EQ(a.find_first_of(b, 3), absl::string_view::npos);
+  EXPECT_EQ(a.find_first_of(c), 23);
+  EXPECT_EQ(a.find_first_of(c, 23), 23);
+  EXPECT_EQ(a.find_first_of(c, 24), 24);
+  EXPECT_EQ(a.find_first_of(c, 25), 25);
+  EXPECT_EQ(a.find_first_of(c, 26), absl::string_view::npos);
+  EXPECT_EQ(g.find_first_of(b), 13);
+  EXPECT_EQ(g.find_first_of(c), 0);
+  EXPECT_EQ(a.find_first_of(f), absl::string_view::npos);
+  EXPECT_EQ(f.find_first_of(a), absl::string_view::npos);
+  // empty std::string nonsense
+  EXPECT_EQ(a.find_first_of(d), absl::string_view::npos);
+  EXPECT_EQ(a.find_first_of(e), absl::string_view::npos);
+  EXPECT_EQ(d.find_first_of(b), absl::string_view::npos);
+  EXPECT_EQ(e.find_first_of(b), absl::string_view::npos);
+  EXPECT_EQ(d.find_first_of(d), absl::string_view::npos);
+  EXPECT_EQ(e.find_first_of(d), absl::string_view::npos);
+  EXPECT_EQ(d.find_first_of(e), absl::string_view::npos);
+  EXPECT_EQ(e.find_first_of(e), absl::string_view::npos);
+
+  EXPECT_EQ(a.find_first_not_of(b), 3);
+  EXPECT_EQ(a.find_first_not_of(c), 0);
+  EXPECT_EQ(b.find_first_not_of(a), absl::string_view::npos);
+  EXPECT_EQ(c.find_first_not_of(a), absl::string_view::npos);
+  EXPECT_EQ(f.find_first_not_of(a), 0);
+  EXPECT_EQ(a.find_first_not_of(f), 0);
+  EXPECT_EQ(a.find_first_not_of(d), 0);
+  EXPECT_EQ(a.find_first_not_of(e), 0);
+  // empty std::string nonsense
+  EXPECT_EQ(a.find_first_not_of(d), 0);
+  EXPECT_EQ(a.find_first_not_of(e), 0);
+  EXPECT_EQ(a.find_first_not_of(d, 1), 1);
+  EXPECT_EQ(a.find_first_not_of(e, 1), 1);
+  EXPECT_EQ(a.find_first_not_of(d, a.size() - 1), a.size() - 1);
+  EXPECT_EQ(a.find_first_not_of(e, a.size() - 1), a.size() - 1);
+  EXPECT_EQ(a.find_first_not_of(d, a.size()), absl::string_view::npos);
+  EXPECT_EQ(a.find_first_not_of(e, a.size()), absl::string_view::npos);
+  EXPECT_EQ(a.find_first_not_of(d, absl::string_view::npos),
+            absl::string_view::npos);
+  EXPECT_EQ(a.find_first_not_of(e, absl::string_view::npos),
+            absl::string_view::npos);
+  EXPECT_EQ(d.find_first_not_of(a), absl::string_view::npos);
+  EXPECT_EQ(e.find_first_not_of(a), absl::string_view::npos);
+  EXPECT_EQ(d.find_first_not_of(d), absl::string_view::npos);
+  EXPECT_EQ(e.find_first_not_of(d), absl::string_view::npos);
+  EXPECT_EQ(d.find_first_not_of(e), absl::string_view::npos);
+  EXPECT_EQ(e.find_first_not_of(e), absl::string_view::npos);
+
+  absl::string_view h("====");
+  EXPECT_EQ(h.find_first_not_of('='), absl::string_view::npos);
+  EXPECT_EQ(h.find_first_not_of('=', 3), absl::string_view::npos);
+  EXPECT_EQ(h.find_first_not_of('\0'), 0);
+  EXPECT_EQ(g.find_first_not_of('x'), 2);
+  EXPECT_EQ(f.find_first_not_of('\0'), 0);
+  EXPECT_EQ(f.find_first_not_of('\0', 3), 4);
+  EXPECT_EQ(f.find_first_not_of('\0', 2), 2);
+  // empty std::string nonsense
+  EXPECT_EQ(d.find_first_not_of('x'), absl::string_view::npos);
+  EXPECT_EQ(e.find_first_not_of('x'), absl::string_view::npos);
+  EXPECT_EQ(d.find_first_not_of('\0'), absl::string_view::npos);
+  EXPECT_EQ(e.find_first_not_of('\0'), absl::string_view::npos);
+}
+
+// Continued from STL2
+TEST(StringViewTest, STL2FindLast) {
+  const absl::string_view a("abcdefghijklmnopqrstuvwxyz");
+  const absl::string_view b("abc");
+  const absl::string_view c("xyz");
+  absl::string_view d("foobar");
+  const absl::string_view e;
+  const absl::string_view f(
+      "123"
+      "\0"
+      "456",
+      7);
+  absl::string_view g("xx not found bb");
+  absl::string_view h("====");
+  absl::string_view i("56");
+
+  d = absl::string_view();
+  EXPECT_EQ(h.find_last_of(a), absl::string_view::npos);
+  EXPECT_EQ(g.find_last_of(a), g.size()-1);
+  EXPECT_EQ(a.find_last_of(b), 2);
+  EXPECT_EQ(a.find_last_of(c), a.size()-1);
+  EXPECT_EQ(f.find_last_of(i), 6);
+  EXPECT_EQ(a.find_last_of('a'), 0);
+  EXPECT_EQ(a.find_last_of('b'), 1);
+  EXPECT_EQ(a.find_last_of('z'), 25);
+  EXPECT_EQ(a.find_last_of('a', 5), 0);
+  EXPECT_EQ(a.find_last_of('b', 5), 1);
+  EXPECT_EQ(a.find_last_of('b', 0), absl::string_view::npos);
+  EXPECT_EQ(a.find_last_of('z', 25), 25);
+  EXPECT_EQ(a.find_last_of('z', 24), absl::string_view::npos);
+  EXPECT_EQ(f.find_last_of(i, 5), 5);
+  EXPECT_EQ(f.find_last_of(i, 6), 6);
+  EXPECT_EQ(f.find_last_of(a, 4), absl::string_view::npos);
+  // empty std::string nonsense
+  EXPECT_EQ(f.find_last_of(d), absl::string_view::npos);
+  EXPECT_EQ(f.find_last_of(e), absl::string_view::npos);
+  EXPECT_EQ(f.find_last_of(d, 4), absl::string_view::npos);
+  EXPECT_EQ(f.find_last_of(e, 4), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_of(d), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_of(e), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_of(d), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_of(e), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_of(f), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_of(f), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_of(d, 4), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_of(e, 4), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_of(d, 4), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_of(e, 4), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_of(f, 4), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_of(f, 4), absl::string_view::npos);
+
+  EXPECT_EQ(a.find_last_not_of(b), a.size()-1);
+  EXPECT_EQ(a.find_last_not_of(c), 22);
+  EXPECT_EQ(b.find_last_not_of(a), absl::string_view::npos);
+  EXPECT_EQ(b.find_last_not_of(b), absl::string_view::npos);
+  EXPECT_EQ(f.find_last_not_of(i), 4);
+  EXPECT_EQ(a.find_last_not_of(c, 24), 22);
+  EXPECT_EQ(a.find_last_not_of(b, 3), 3);
+  EXPECT_EQ(a.find_last_not_of(b, 2), absl::string_view::npos);
+  // empty std::string nonsense
+  EXPECT_EQ(f.find_last_not_of(d), f.size()-1);
+  EXPECT_EQ(f.find_last_not_of(e), f.size()-1);
+  EXPECT_EQ(f.find_last_not_of(d, 4), 4);
+  EXPECT_EQ(f.find_last_not_of(e, 4), 4);
+  EXPECT_EQ(d.find_last_not_of(d), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_not_of(e), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_not_of(d), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_not_of(e), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_not_of(f), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_not_of(f), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_not_of(d, 4), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_not_of(e, 4), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_not_of(d, 4), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_not_of(e, 4), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_not_of(f, 4), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_not_of(f, 4), absl::string_view::npos);
+
+  EXPECT_EQ(h.find_last_not_of('x'), h.size() - 1);
+  EXPECT_EQ(h.find_last_not_of('='), absl::string_view::npos);
+  EXPECT_EQ(b.find_last_not_of('c'), 1);
+  EXPECT_EQ(h.find_last_not_of('x', 2), 2);
+  EXPECT_EQ(h.find_last_not_of('=', 2), absl::string_view::npos);
+  EXPECT_EQ(b.find_last_not_of('b', 1), 0);
+  // empty std::string nonsense
+  EXPECT_EQ(d.find_last_not_of('x'), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_not_of('x'), absl::string_view::npos);
+  EXPECT_EQ(d.find_last_not_of('\0'), absl::string_view::npos);
+  EXPECT_EQ(e.find_last_not_of('\0'), absl::string_view::npos);
+}
+
+// Continued from STL2
+TEST(StringViewTest, STL2Substr) {
+  const absl::string_view a("abcdefghijklmnopqrstuvwxyz");
+  const absl::string_view b("abc");
+  const absl::string_view c("xyz");
+  absl::string_view d("foobar");
+  const absl::string_view e;
+
+  d = absl::string_view();
+  EXPECT_EQ(a.substr(0, 3), b);
+  EXPECT_EQ(a.substr(23), c);
+  EXPECT_EQ(a.substr(23, 3), c);
+  EXPECT_EQ(a.substr(23, 99), c);
+  EXPECT_EQ(a.substr(0), a);
+  EXPECT_EQ(a.substr(3, 2), "de");
+  // empty std::string nonsense
+  EXPECT_EQ(d.substr(0, 99), e);
+  // use of npos
+  EXPECT_EQ(a.substr(0, absl::string_view::npos), a);
+  EXPECT_EQ(a.substr(23, absl::string_view::npos), c);
+  // throw exception
+#ifdef ABSL_HAVE_EXCEPTIONS
+  EXPECT_THROW(a.substr(99, 2), std::out_of_range);
+#else
+  EXPECT_DEATH(a.substr(99, 2), "absl::string_view::substr");
+#endif
+}
+
+TEST(StringViewTest, TruncSubstr) {
+  const absl::string_view hi("hi");
+  EXPECT_EQ("", absl::ClippedSubstr(hi, 0, 0));
+  EXPECT_EQ("h", absl::ClippedSubstr(hi, 0, 1));
+  EXPECT_EQ("hi", absl::ClippedSubstr(hi, 0));
+  EXPECT_EQ("i", absl::ClippedSubstr(hi, 1));
+  EXPECT_EQ("", absl::ClippedSubstr(hi, 2));
+  EXPECT_EQ("", absl::ClippedSubstr(hi, 3));  // truncation
+  EXPECT_EQ("", absl::ClippedSubstr(hi, 3, 2));  // truncation
+}
+
+TEST(StringViewTest, UTF8) {
+  std::string utf8 = "\u00E1";
+  std::string utf8_twice = utf8 + " " + utf8;
+  int utf8_len = strlen(utf8.data());
+  EXPECT_EQ(utf8_len, absl::string_view(utf8_twice).find_first_of(" "));
+  EXPECT_EQ(utf8_len, absl::string_view(utf8_twice).find_first_of(" \t"));
+}
+
+TEST(StringViewTest, FindConformance) {
+  struct {
+    std::string haystack;
+    std::string needle;
+  } specs[] = {
+    {"", ""},
+    {"", "a"},
+    {"a", ""},
+    {"a", "a"},
+    {"a", "b"},
+    {"aa", ""},
+    {"aa", "a"},
+    {"aa", "b"},
+    {"ab", "a"},
+    {"ab", "b"},
+    {"abcd", ""},
+    {"abcd", "a"},
+    {"abcd", "d"},
+    {"abcd", "ab"},
+    {"abcd", "bc"},
+    {"abcd", "cd"},
+    {"abcd", "abcd"},
+  };
+  for (const auto& s : specs) {
+    SCOPED_TRACE(s.haystack);
+    SCOPED_TRACE(s.needle);
+    std::string st = s.haystack;
+    absl::string_view sp = s.haystack;
+    for (size_t i = 0; i <= sp.size(); ++i) {
+      size_t pos = (i == sp.size()) ? absl::string_view::npos : i;
+      SCOPED_TRACE(pos);
+      EXPECT_EQ(sp.find(s.needle, pos),
+                st.find(s.needle, pos));
+      EXPECT_EQ(sp.rfind(s.needle, pos),
+                st.rfind(s.needle, pos));
+      EXPECT_EQ(sp.find_first_of(s.needle, pos),
+                st.find_first_of(s.needle, pos));
+      EXPECT_EQ(sp.find_first_not_of(s.needle, pos),
+                st.find_first_not_of(s.needle, pos));
+      EXPECT_EQ(sp.find_last_of(s.needle, pos),
+                st.find_last_of(s.needle, pos));
+      EXPECT_EQ(sp.find_last_not_of(s.needle, pos),
+                st.find_last_not_of(s.needle, pos));
+    }
+  }
+}
+
+TEST(StringViewTest, Remove) {
+  absl::string_view a("foobar");
+  std::string s1("123");
+  s1 += '\0';
+  s1 += "456";
+  absl::string_view b(s1);
+  absl::string_view e;
+  std::string s2;
+
+  // remove_prefix
+  absl::string_view c(a);
+  c.remove_prefix(3);
+  EXPECT_EQ(c, "bar");
+  c = a;
+  c.remove_prefix(0);
+  EXPECT_EQ(c, a);
+  c.remove_prefix(c.size());
+  EXPECT_EQ(c, e);
+
+  // remove_suffix
+  c = a;
+  c.remove_suffix(3);
+  EXPECT_EQ(c, "foo");
+  c = a;
+  c.remove_suffix(0);
+  EXPECT_EQ(c, a);
+  c.remove_suffix(c.size());
+  EXPECT_EQ(c, e);
+}
+
+TEST(StringViewTest, Set) {
+  absl::string_view a("foobar");
+  absl::string_view empty;
+  absl::string_view b;
+
+  // set
+  b = absl::string_view("foobar", 6);
+  EXPECT_EQ(b, a);
+  b = absl::string_view("foobar", 0);
+  EXPECT_EQ(b, empty);
+  b = absl::string_view("foobar", 7);
+  EXPECT_NE(b, a);
+
+  b = absl::string_view("foobar");
+  EXPECT_EQ(b, a);
+}
+
+TEST(StringViewTest, FrontBack) {
+  static const char arr[] = "abcd";
+  const absl::string_view csp(arr, 4);
+  EXPECT_EQ(&arr[0], &csp.front());
+  EXPECT_EQ(&arr[3], &csp.back());
+}
+
+TEST(StringViewTest, FrontBackSingleChar) {
+  static const char c = 'a';
+  const absl::string_view csp(&c, 1);
+  EXPECT_EQ(&c, &csp.front());
+  EXPECT_EQ(&c, &csp.back());
+}
+
+// `std::string_view::string_view(const char*)` calls
+// `std::char_traits<char>::length(const char*)` to get the std::string 
length. In
+// libc++, it doesn't allow `nullptr` in the constexpr context, with the error
+// "read of dereferenced null pointer is not allowed in a constant expression".
+// At run time, the behavior of `std::char_traits::length()` on `nullptr` is
+// undefined by the standard and usually results in crash with libc++. This
+// conforms to the standard, but `absl::string_view` implements a different
+// behavior for historical reasons. We work around tests that construct
+// `string_view` from `nullptr` when using libc++.
+#if !defined(ABSL_HAVE_STD_STRING_VIEW) || !defined(_LIBCPP_VERSION)
+#define ABSL_HAVE_STRING_VIEW_FROM_NULLPTR 1
+#endif  // !defined(ABSL_HAVE_STD_STRING_VIEW) || !defined(_LIBCPP_VERSION)
+
+TEST(StringViewTest, NULLInput) {
+  absl::string_view s;
+  EXPECT_EQ(s.data(), nullptr);
+  EXPECT_EQ(s.size(), 0);
+
+#ifdef ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
+  s = absl::string_view(nullptr);
+  EXPECT_EQ(s.data(), nullptr);
+  EXPECT_EQ(s.size(), 0);
+
+  // .ToString() on a absl::string_view with nullptr should produce the empty
+  // std::string.
+  EXPECT_EQ("", std::string(s));
+#endif  // ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
+}
+
+TEST(StringViewTest, Comparisons2) {
+  // The `compare` member has 6 overloads (v: string_view, s: const char*):
+  //  (1) compare(v)
+  //  (2) compare(pos1, count1, v)
+  //  (3) compare(pos1, count1, v, pos2, count2)
+  //  (4) compare(s)
+  //  (5) compare(pos1, count1, s)
+  //  (6) compare(pos1, count1, s, count2)
+
+  absl::string_view abc("abcdefghijklmnopqrstuvwxyz");
+
+  // check comparison operations on strings longer than 4 bytes.
+  EXPECT_EQ(abc, absl::string_view("abcdefghijklmnopqrstuvwxyz"));
+  EXPECT_EQ(abc.compare(absl::string_view("abcdefghijklmnopqrstuvwxyz")), 0);
+
+  EXPECT_LT(abc, absl::string_view("abcdefghijklmnopqrstuvwxzz"));
+  EXPECT_LT(abc.compare(absl::string_view("abcdefghijklmnopqrstuvwxzz")), 0);
+
+  EXPECT_GT(abc, absl::string_view("abcdefghijklmnopqrstuvwxyy"));
+  EXPECT_GT(abc.compare(absl::string_view("abcdefghijklmnopqrstuvwxyy")), 0);
+
+  // The "substr" variants of `compare`.
+  absl::string_view digits("0123456789");
+  auto npos = absl::string_view::npos;
+
+  // Taking string_view
+  EXPECT_EQ(digits.compare(3, npos, absl::string_view("3456789")), 0);  // 2
+  EXPECT_EQ(digits.compare(3, 4, absl::string_view("3456")), 0);        // 2
+  EXPECT_EQ(digits.compare(10, 0, absl::string_view()), 0);             // 2
+  EXPECT_EQ(digits.compare(3, 4, absl::string_view("0123456789"), 3, 4),
+            0);  // 3
+  EXPECT_LT(digits.compare(3, 4, absl::string_view("0123456789"), 3, 5),
+            0);  // 3
+  EXPECT_LT(digits.compare(0, npos, absl::string_view("0123456789"), 3, 5),
+            0);  // 3
+  // Taking const char*
+  EXPECT_EQ(digits.compare(3, 4, "3456"), 0);                 // 5
+  EXPECT_EQ(digits.compare(3, npos, "3456789"), 0);           // 5
+  EXPECT_EQ(digits.compare(10, 0, ""), 0);                    // 5
+  EXPECT_EQ(digits.compare(3, 4, "0123456789", 3, 4), 0);     // 6
+  EXPECT_LT(digits.compare(3, 4, "0123456789", 3, 5), 0);     // 6
+  EXPECT_LT(digits.compare(0, npos, "0123456789", 3, 5), 0);  // 6
+}
+
+struct MyCharAlloc : std::allocator<char> {};
+
+TEST(StringViewTest, ExplicitConversionOperator) {
+  absl::string_view sp = "hi";
+  EXPECT_EQ(sp, std::string(sp));
+}
+
+TEST(StringViewTest, NullSafeStringView) {
+  {
+    absl::string_view s = absl::NullSafeStringView(nullptr);
+    EXPECT_EQ(nullptr, s.data());
+    EXPECT_EQ(0, s.size());
+    EXPECT_EQ(absl::string_view(), s);
+  }
+  {
+    static const char kHi[] = "hi";
+    absl::string_view s = absl::NullSafeStringView(kHi);
+    EXPECT_EQ(kHi, s.data());
+    EXPECT_EQ(strlen(kHi), s.size());
+    EXPECT_EQ(absl::string_view("hi"), s);
+  }
+}
+
+TEST(StringViewTest, ConstexprCompiles) {
+  constexpr absl::string_view sp;
+#ifdef ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
+  constexpr absl::string_view cstr(nullptr);
+#endif
+  constexpr absl::string_view cstr_len("cstr", 4);
+
+#if defined(ABSL_HAVE_STD_STRING_VIEW)
+  // In libstdc++ (as of 7.2), `std::string_view::string_view(const char*)`
+  // calls `std::char_traits<char>::length(const char*)` to get the std::string
+  // length, but it is not marked constexpr yet. See GCC bug:
+  // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78156
+  // Also, there is a LWG issue that adds constexpr to length() which was just
+  // resolved 2017-06-02. See
+  // http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2232
+  // TODO(zhangxy): Update the condition when libstdc++ adopts the constexpr
+  // length().
+#if !defined(__GLIBCXX__)
+#define ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR 1
+#endif  // !__GLIBCXX__
+
+#else  // ABSL_HAVE_STD_STRING_VIEW
+
+// This duplicates the check for __builtin_strlen in the header.
+#if ABSL_HAVE_BUILTIN(__builtin_strlen) || \
+    (defined(__GNUC__) && !defined(__clang__))
+#define ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR 1
+#elif defined(__GNUC__)  // GCC or clang
+#error GCC/clang should have constexpr string_view.
+#endif
+
+#endif  // ABSL_HAVE_STD_STRING_VIEW
+
+#ifdef ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR
+  constexpr absl::string_view cstr_strlen("foo");
+  EXPECT_EQ(cstr_strlen.length(), 3);
+  constexpr absl::string_view cstr_strlen2 = "bar";
+  EXPECT_EQ(cstr_strlen2, "bar");
+#endif
+
+#if !defined(__clang__) || 3 < __clang_major__ || \
+  (3 == __clang_major__ && 4 < __clang_minor__)
+  // older clang versions (< 3.5) complain that:
+  //   "cannot perform pointer arithmetic on null pointer"
+  constexpr absl::string_view::iterator const_begin_empty = sp.begin();
+  constexpr absl::string_view::iterator const_end_empty = sp.end();
+  EXPECT_EQ(const_begin_empty, const_end_empty);
+
+#ifdef ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
+  constexpr absl::string_view::iterator const_begin_nullptr = cstr.begin();
+  constexpr absl::string_view::iterator const_end_nullptr = cstr.end();
+  EXPECT_EQ(const_begin_nullptr, const_end_nullptr);
+#endif  // ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
+#endif  // !defined(__clang__) || ...
+
+  constexpr absl::string_view::iterator const_begin = cstr_len.begin();
+  constexpr absl::string_view::iterator const_end = cstr_len.end();
+  constexpr absl::string_view::size_type const_size = cstr_len.size();
+  constexpr absl::string_view::size_type const_length = cstr_len.length();
+  EXPECT_EQ(const_begin + const_size, const_end);
+  EXPECT_EQ(const_begin + const_length, const_end);
+
+  constexpr bool isempty = sp.empty();
+  EXPECT_TRUE(isempty);
+
+  constexpr const char c = cstr_len[2];
+  EXPECT_EQ(c, 't');
+
+  constexpr const char cfront = cstr_len.front();
+  constexpr const char cback = cstr_len.back();
+  EXPECT_EQ(cfront, 'c');
+  EXPECT_EQ(cback, 'r');
+
+  constexpr const char* np = sp.data();
+  constexpr const char* cstr_ptr = cstr_len.data();
+  EXPECT_EQ(np, nullptr);
+  EXPECT_NE(cstr_ptr, nullptr);
+
+  constexpr size_t sp_npos = sp.npos;
+  EXPECT_EQ(sp_npos, -1);
+}
+
+TEST(StringViewTest, Noexcept) {
+  EXPECT_TRUE((std::is_nothrow_constructible<absl::string_view,
+                                             const std::string&>::value));
+  EXPECT_TRUE(
+      (std::is_nothrow_constructible<absl::string_view, const 
std::string&>::value));
+  EXPECT_TRUE(std::is_nothrow_constructible<absl::string_view>::value);
+  constexpr absl::string_view sp;
+  EXPECT_TRUE(noexcept(sp.begin()));
+  EXPECT_TRUE(noexcept(sp.end()));
+  EXPECT_TRUE(noexcept(sp.cbegin()));
+  EXPECT_TRUE(noexcept(sp.cend()));
+  EXPECT_TRUE(noexcept(sp.rbegin()));
+  EXPECT_TRUE(noexcept(sp.rend()));
+  EXPECT_TRUE(noexcept(sp.crbegin()));
+  EXPECT_TRUE(noexcept(sp.crend()));
+  EXPECT_TRUE(noexcept(sp.size()));
+  EXPECT_TRUE(noexcept(sp.length()));
+  EXPECT_TRUE(noexcept(sp.empty()));
+  EXPECT_TRUE(noexcept(sp.data()));
+  EXPECT_TRUE(noexcept(sp.compare(sp)));
+  EXPECT_TRUE(noexcept(sp.find(sp)));
+  EXPECT_TRUE(noexcept(sp.find('f')));
+  EXPECT_TRUE(noexcept(sp.rfind(sp)));
+  EXPECT_TRUE(noexcept(sp.rfind('f')));
+  EXPECT_TRUE(noexcept(sp.find_first_of(sp)));
+  EXPECT_TRUE(noexcept(sp.find_first_of('f')));
+  EXPECT_TRUE(noexcept(sp.find_last_of(sp)));
+  EXPECT_TRUE(noexcept(sp.find_last_of('f')));
+  EXPECT_TRUE(noexcept(sp.find_first_not_of(sp)));
+  EXPECT_TRUE(noexcept(sp.find_first_not_of('f')));
+  EXPECT_TRUE(noexcept(sp.find_last_not_of(sp)));
+  EXPECT_TRUE(noexcept(sp.find_last_not_of('f')));
+}
+
+TEST(ComparisonOpsTest, StringCompareNotAmbiguous) {
+  EXPECT_EQ("hello", std::string("hello"));
+  EXPECT_LT("hello", std::string("world"));
+}
+
+TEST(ComparisonOpsTest, HeterogenousStringViewEquals) {
+  EXPECT_EQ(absl::string_view("hello"), std::string("hello"));
+  EXPECT_EQ("hello", absl::string_view("hello"));
+}
+
+TEST(FindOneCharTest, EdgeCases) {
+  absl::string_view a("xxyyyxx");
+
+  // Set a = "xyyyx".
+  a.remove_prefix(1);
+  a.remove_suffix(1);
+
+  EXPECT_EQ(0, a.find('x'));
+  EXPECT_EQ(0, a.find('x', 0));
+  EXPECT_EQ(4, a.find('x', 1));
+  EXPECT_EQ(4, a.find('x', 4));
+  EXPECT_EQ(absl::string_view::npos, a.find('x', 5));
+
+  EXPECT_EQ(4, a.rfind('x'));
+  EXPECT_EQ(4, a.rfind('x', 5));
+  EXPECT_EQ(4, a.rfind('x', 4));
+  EXPECT_EQ(0, a.rfind('x', 3));
+  EXPECT_EQ(0, a.rfind('x', 0));
+
+  // Set a = "yyy".
+  a.remove_prefix(1);
+  a.remove_suffix(1);
+
+  EXPECT_EQ(absl::string_view::npos, a.find('x'));
+  EXPECT_EQ(absl::string_view::npos, a.rfind('x'));
+}
+
+#ifndef THREAD_SANITIZER  // Allocates too much memory for tsan.
+TEST(HugeStringView, TwoPointTwoGB) {
+  if (sizeof(size_t) <= 4 || RunningOnValgrind())
+    return;
+  // Try a huge std::string piece.
+  const size_t size = size_t{2200} * 1000 * 1000;
+  std::string s(size, 'a');
+  absl::string_view sp(s);
+  EXPECT_EQ(size, sp.length());
+  sp.remove_prefix(1);
+  EXPECT_EQ(size - 1, sp.length());
+  sp.remove_suffix(2);
+  EXPECT_EQ(size - 1 - 2, sp.length());
+}
+#endif  // THREAD_SANITIZER
+
+#if !defined(NDEBUG) && !defined(ABSL_HAVE_STD_STRING_VIEW)
+TEST(NonNegativeLenTest, NonNegativeLen) {
+  EXPECT_DEATH_IF_SUPPORTED(absl::string_view("xyz", -1), "len <= kMaxSize");
+}
+
+TEST(LenExceedsMaxSizeTest, LenExceedsMaxSize) {
+  auto max_size = absl::string_view().max_size();
+
+  // This should construct ok (although the view itself is obviously invalid).
+  absl::string_view ok_view("", max_size);
+
+  // Adding one to the max should trigger an assertion.
+  EXPECT_DEATH_IF_SUPPORTED(absl::string_view("", max_size + 1),
+                            "len <= kMaxSize");
+}
+#endif  // !defined(NDEBUG) && !defined(ABSL_HAVE_STD_STRING_VIEW)
+
+class StringViewStreamTest : public ::testing::Test {
+ public:
+  // Set negative 'width' for right justification.
+  template <typename T>
+  std::string Pad(const T& s, int width, char fill = 0) {
+    std::ostringstream oss;
+    if (fill != 0) {
+      oss << std::setfill(fill);
+    }
+    if (width < 0) {
+      width = -width;
+      oss << std::right;
+    }
+    oss << std::setw(width) << s;
+    return oss.str();
+  }
+};
+
+TEST_F(StringViewStreamTest, Padding) {
+  std::string s("hello");
+  absl::string_view sp(s);
+  for (int w = -64; w < 64; ++w) {
+    SCOPED_TRACE(w);
+    EXPECT_EQ(Pad(s, w), Pad(sp, w));
+  }
+  for (int w = -64; w < 64; ++w) {
+    SCOPED_TRACE(w);
+    EXPECT_EQ(Pad(s, w, '#'), Pad(sp, w, '#'));
+  }
+}
+
+TEST_F(StringViewStreamTest, ResetsWidth) {
+  // Width should reset after one formatted write.
+  // If we weren't resetting width after formatting the string_view,
+  // we'd have width=5 carrying over to the printing of the "]",
+  // creating "[###hi####]".
+  std::string s = "hi";
+  absl::string_view sp = s;
+  {
+    std::ostringstream oss;
+    oss << "[" << std::setfill('#') << std::setw(5) << s << "]";
+    ASSERT_EQ("[###hi]", oss.str());
+  }
+  {
+    std::ostringstream oss;
+    oss << "[" << std::setfill('#') << std::setw(5) << sp << "]";
+    EXPECT_EQ("[###hi]", oss.str());
+  }
+}
+
+}  // namespace

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/strings/strip.h
----------------------------------------------------------------------
diff --git a/libraries/ostrich/backend/3rdparty/abseil/absl/strings/strip.h 
b/libraries/ostrich/backend/3rdparty/abseil/absl/strings/strip.h
new file mode 100644
index 0000000..2f8d21f
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/strings/strip.h
@@ -0,0 +1,89 @@
+//
+// Copyright 2017 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
+//
+//      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.
+//
+// 
-----------------------------------------------------------------------------
+// File: strip.h
+// 
-----------------------------------------------------------------------------
+//
+// This file contains various functions for stripping substrings from a 
std::string.
+#ifndef ABSL_STRINGS_STRIP_H_
+#define ABSL_STRINGS_STRIP_H_
+
+#include <cstddef>
+#include <string>
+
+#include "absl/base/macros.h"
+#include "absl/strings/ascii.h"
+#include "absl/strings/match.h"
+#include "absl/strings/string_view.h"
+
+namespace absl {
+
+// ConsumePrefix()
+//
+// Strips the `expected` prefix from the start of the given std::string, 
returning
+// `true` if the strip operation succeeded or false otherwise.
+//
+// Example:
+//
+//   absl::string_view input("abc");
+//   EXPECT_TRUE(absl::ConsumePrefix(&input, "a"));
+//   EXPECT_EQ(input, "bc");
+inline bool ConsumePrefix(absl::string_view* str, absl::string_view expected) {
+  if (!absl::StartsWith(*str, expected)) return false;
+  str->remove_prefix(expected.size());
+  return true;
+}
+// ConsumeSuffix()
+//
+// Strips the `expected` suffix from the end of the given std::string, 
returning
+// `true` if the strip operation succeeded or false otherwise.
+//
+// Example:
+//
+//   absl::string_view input("abcdef");
+//   EXPECT_TRUE(absl::ConsumeSuffix(&input, "def"));
+//   EXPECT_EQ(input, "abc");
+inline bool ConsumeSuffix(absl::string_view* str, absl::string_view expected) {
+  if (!absl::EndsWith(*str, expected)) return false;
+  str->remove_suffix(expected.size());
+  return true;
+}
+
+// StripPrefix()
+//
+// Returns a view into the input std::string 'str' with the given 'prefix' 
removed,
+// but leaving the original std::string intact. If the prefix does not match 
at the
+// start of the std::string, returns the original std::string instead.
+ABSL_MUST_USE_RESULT inline absl::string_view StripPrefix(
+    absl::string_view str, absl::string_view prefix) {
+  if (absl::StartsWith(str, prefix)) str.remove_prefix(prefix.size());
+  return str;
+}
+
+// StripSuffix()
+//
+// Returns a view into the input std::string 'str' with the given 'suffix' 
removed,
+// but leaving the original std::string intact. If the suffix does not match 
at the
+// end of the std::string, returns the original std::string instead.
+ABSL_MUST_USE_RESULT inline absl::string_view StripSuffix(
+    absl::string_view str, absl::string_view suffix) {
+  if (absl::EndsWith(str, suffix)) str.remove_suffix(suffix.size());
+  return str;
+}
+
+}  // namespace absl
+
+#endif  // ABSL_STRINGS_STRIP_H_

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/strings/strip_test.cc
----------------------------------------------------------------------
diff --git 
a/libraries/ostrich/backend/3rdparty/abseil/absl/strings/strip_test.cc 
b/libraries/ostrich/backend/3rdparty/abseil/absl/strings/strip_test.cc
new file mode 100644
index 0000000..205c160
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/strings/strip_test.cc
@@ -0,0 +1,201 @@
+// Copyright 2017 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
+//
+//      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.
+
+// This file contains functions that remove a defined part from the 
std::string,
+// i.e., strip the std::string.
+
+#include "absl/strings/strip.h"
+
+#include <cassert>
+#include <cstdio>
+#include <cstring>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/strings/string_view.h"
+
+namespace {
+
+using testing::ElementsAre;
+using testing::IsEmpty;
+
+TEST(Strip, ConsumePrefixOneChar) {
+  absl::string_view input("abc");
+  EXPECT_TRUE(absl::ConsumePrefix(&input, "a"));
+  EXPECT_EQ(input, "bc");
+
+  EXPECT_FALSE(absl::ConsumePrefix(&input, "x"));
+  EXPECT_EQ(input, "bc");
+
+  EXPECT_TRUE(absl::ConsumePrefix(&input, "b"));
+  EXPECT_EQ(input, "c");
+
+  EXPECT_TRUE(absl::ConsumePrefix(&input, "c"));
+  EXPECT_EQ(input, "");
+
+  EXPECT_FALSE(absl::ConsumePrefix(&input, "a"));
+  EXPECT_EQ(input, "");
+}
+
+TEST(Strip, ConsumePrefix) {
+  absl::string_view input("abcdef");
+  EXPECT_FALSE(absl::ConsumePrefix(&input, "abcdefg"));
+  EXPECT_EQ(input, "abcdef");
+
+  EXPECT_FALSE(absl::ConsumePrefix(&input, "abce"));
+  EXPECT_EQ(input, "abcdef");
+
+  EXPECT_TRUE(absl::ConsumePrefix(&input, ""));
+  EXPECT_EQ(input, "abcdef");
+
+  EXPECT_FALSE(absl::ConsumePrefix(&input, "abcdeg"));
+  EXPECT_EQ(input, "abcdef");
+
+  EXPECT_TRUE(absl::ConsumePrefix(&input, "abcdef"));
+  EXPECT_EQ(input, "");
+
+  input = "abcdef";
+  EXPECT_TRUE(absl::ConsumePrefix(&input, "abcde"));
+  EXPECT_EQ(input, "f");
+}
+
+TEST(Strip, ConsumeSuffix) {
+  absl::string_view input("abcdef");
+  EXPECT_FALSE(absl::ConsumeSuffix(&input, "abcdefg"));
+  EXPECT_EQ(input, "abcdef");
+
+  EXPECT_TRUE(absl::ConsumeSuffix(&input, ""));
+  EXPECT_EQ(input, "abcdef");
+
+  EXPECT_TRUE(absl::ConsumeSuffix(&input, "def"));
+  EXPECT_EQ(input, "abc");
+
+  input = "abcdef";
+  EXPECT_FALSE(absl::ConsumeSuffix(&input, "abcdeg"));
+  EXPECT_EQ(input, "abcdef");
+
+  EXPECT_TRUE(absl::ConsumeSuffix(&input, "f"));
+  EXPECT_EQ(input, "abcde");
+
+  EXPECT_TRUE(absl::ConsumeSuffix(&input, "abcde"));
+  EXPECT_EQ(input, "");
+}
+
+TEST(Strip, StripPrefix) {
+  const absl::string_view null_str;
+
+  EXPECT_EQ(absl::StripPrefix("foobar", "foo"), "bar");
+  EXPECT_EQ(absl::StripPrefix("foobar", ""), "foobar");
+  EXPECT_EQ(absl::StripPrefix("foobar", null_str), "foobar");
+  EXPECT_EQ(absl::StripPrefix("foobar", "foobar"), "");
+  EXPECT_EQ(absl::StripPrefix("foobar", "bar"), "foobar");
+  EXPECT_EQ(absl::StripPrefix("foobar", "foobarr"), "foobar");
+  EXPECT_EQ(absl::StripPrefix("", ""), "");
+}
+
+TEST(Strip, StripSuffix) {
+  const absl::string_view null_str;
+
+  EXPECT_EQ(absl::StripSuffix("foobar", "bar"), "foo");
+  EXPECT_EQ(absl::StripSuffix("foobar", ""), "foobar");
+  EXPECT_EQ(absl::StripSuffix("foobar", null_str), "foobar");
+  EXPECT_EQ(absl::StripSuffix("foobar", "foobar"), "");
+  EXPECT_EQ(absl::StripSuffix("foobar", "foo"), "foobar");
+  EXPECT_EQ(absl::StripSuffix("foobar", "ffoobar"), "foobar");
+  EXPECT_EQ(absl::StripSuffix("", ""), "");
+}
+
+TEST(Strip, RemoveExtraAsciiWhitespace) {
+  const char* inputs[] = {
+      "No extra space",
+      "  Leading whitespace",
+      "Trailing whitespace  ",
+      "  Leading and trailing  ",
+      " Whitespace \t  in\v   middle  ",
+      "'Eeeeep!  \n Newlines!\n",
+      "nospaces",
+  };
+  const char* outputs[] = {
+      "No extra space",
+      "Leading whitespace",
+      "Trailing whitespace",
+      "Leading and trailing",
+      "Whitespace in middle",
+      "'Eeeeep! Newlines!",
+      "nospaces",
+  };
+  int NUM_TESTS = 7;
+
+  for (int i = 0; i < NUM_TESTS; i++) {
+    std::string s(inputs[i]);
+    absl::RemoveExtraAsciiWhitespace(&s);
+    EXPECT_STREQ(outputs[i], s.c_str());
+  }
+
+  // Test that absl::RemoveExtraAsciiWhitespace returns immediately for empty
+  // strings (It was adding the \0 character to the C++ std::string, which 
broke
+  // tests involving empty())
+  std::string zero_string = "";
+  assert(zero_string.empty());
+  absl::RemoveExtraAsciiWhitespace(&zero_string);
+  EXPECT_EQ(zero_string.size(), 0);
+  EXPECT_TRUE(zero_string.empty());
+}
+
+TEST(Strip, StripTrailingAsciiWhitespace) {
+  std::string test = "foo  ";
+  absl::StripTrailingAsciiWhitespace(&test);
+  EXPECT_EQ(test, "foo");
+
+  test = "   ";
+  absl::StripTrailingAsciiWhitespace(&test);
+  EXPECT_EQ(test, "");
+
+  test = "";
+  absl::StripTrailingAsciiWhitespace(&test);
+  EXPECT_EQ(test, "");
+
+  test = " abc\t";
+  absl::StripTrailingAsciiWhitespace(&test);
+  EXPECT_EQ(test, " abc");
+}
+
+TEST(String, StripLeadingAsciiWhitespace) {
+  absl::string_view orig = "\t  \n\f\r\n\vfoo";
+  EXPECT_EQ("foo", absl::StripLeadingAsciiWhitespace(orig));
+  orig = "\t  \n\f\r\v\n\t  \n\f\r\v\n";
+  EXPECT_EQ(absl::string_view(), absl::StripLeadingAsciiWhitespace(orig));
+}
+
+TEST(Strip, StripAsciiWhitespace) {
+  std::string test2 = "\t  \f\r\n\vfoo \t\f\r\v\n";
+  absl::StripAsciiWhitespace(&test2);
+  EXPECT_EQ(test2, "foo");
+  std::string test3 = "bar";
+  absl::StripAsciiWhitespace(&test3);
+  EXPECT_EQ(test3, "bar");
+  std::string test4 = "\t  \f\r\n\vfoo";
+  absl::StripAsciiWhitespace(&test4);
+  EXPECT_EQ(test4, "foo");
+  std::string test5 = "foo \t\f\r\v\n";
+  absl::StripAsciiWhitespace(&test5);
+  EXPECT_EQ(test5, "foo");
+  absl::string_view test6("\t  \f\r\n\vfoo \t\f\r\v\n");
+  test6 = absl::StripAsciiWhitespace(test6);
+  EXPECT_EQ(test6, "foo");
+  test6 = absl::StripAsciiWhitespace(test6);
+  EXPECT_EQ(test6, "foo");  // already stripped
+}
+
+}  // namespace

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/strings/substitute.cc
----------------------------------------------------------------------
diff --git 
a/libraries/ostrich/backend/3rdparty/abseil/absl/strings/substitute.cc 
b/libraries/ostrich/backend/3rdparty/abseil/absl/strings/substitute.cc
new file mode 100644
index 0000000..3b20059
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/strings/substitute.cc
@@ -0,0 +1,170 @@
+// Copyright 2017 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
+//
+//      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 "absl/strings/substitute.h"
+
+#include <algorithm>
+
+#include "absl/base/internal/raw_logging.h"
+#include "absl/strings/ascii.h"
+#include "absl/strings/escaping.h"
+#include "absl/strings/internal/resize_uninitialized.h"
+#include "absl/strings/string_view.h"
+
+namespace absl {
+namespace substitute_internal {
+
+void SubstituteAndAppendArray(std::string* output, absl::string_view format,
+                              const absl::string_view* args_array,
+                              size_t num_args) {
+  // Determine total size needed.
+  size_t size = 0;
+  for (size_t i = 0; i < format.size(); i++) {
+    if (format[i] == '$') {
+      if (i + 1 >= format.size()) {
+#ifndef NDEBUG
+        ABSL_RAW_LOG(FATAL,
+                     "Invalid strings::Substitute() format std::string: 
\"%s\".",
+                     absl::CEscape(format).c_str());
+#endif
+        return;
+      } else if (absl::ascii_isdigit(format[i + 1])) {
+        int index = format[i + 1] - '0';
+        if (static_cast<size_t>(index) >= num_args) {
+#ifndef NDEBUG
+          ABSL_RAW_LOG(
+              FATAL,
+              "Invalid strings::Substitute() format std::string: asked for \"$"
+              "%d\", but only %d args were given.  Full format std::string 
was: "
+              "\"%s\".",
+              index, static_cast<int>(num_args), 
absl::CEscape(format).c_str());
+#endif
+          return;
+        }
+        size += args_array[index].size();
+        ++i;  // Skip next char.
+      } else if (format[i + 1] == '$') {
+        ++size;
+        ++i;  // Skip next char.
+      } else {
+#ifndef NDEBUG
+        ABSL_RAW_LOG(FATAL,
+                     "Invalid strings::Substitute() format std::string: 
\"%s\".",
+                     absl::CEscape(format).c_str());
+#endif
+        return;
+      }
+    } else {
+      ++size;
+    }
+  }
+
+  if (size == 0) return;
+
+  // Build the std::string.
+  size_t original_size = output->size();
+  strings_internal::STLStringResizeUninitialized(output, original_size + size);
+  char* target = &(*output)[original_size];
+  for (size_t i = 0; i < format.size(); i++) {
+    if (format[i] == '$') {
+      if (absl::ascii_isdigit(format[i + 1])) {
+        const absl::string_view src = args_array[format[i + 1] - '0'];
+        target = std::copy(src.begin(), src.end(), target);
+        ++i;  // Skip next char.
+      } else if (format[i + 1] == '$') {
+        *target++ = '$';
+        ++i;  // Skip next char.
+      }
+    } else {
+      *target++ = format[i];
+    }
+  }
+
+  assert(target == output->data() + output->size());
+}
+
+static const char kHexDigits[] = "0123456789abcdef";
+Arg::Arg(const void* value) {
+  static_assert(sizeof(scratch_) >= sizeof(value) * 2 + 2,
+                "fix sizeof(scratch_)");
+  if (value == nullptr) {
+    piece_ = "NULL";
+  } else {
+    char* ptr = scratch_ + sizeof(scratch_);
+    uintptr_t num = reinterpret_cast<uintptr_t>(value);
+    do {
+      *--ptr = kHexDigits[num & 0xf];
+      num >>= 4;
+    } while (num != 0);
+    *--ptr = 'x';
+    *--ptr = '0';
+    piece_ = absl::string_view(ptr, scratch_ + sizeof(scratch_) - ptr);
+  }
+}
+
+// TODO(jorg): Don't duplicate so much code between here and str_cat.cc
+Arg::Arg(Hex hex) {
+  char* const end = &scratch_[numbers_internal::kFastToBufferSize];
+  char* writer = end;
+  uint64_t value = hex.value;
+  do {
+    *--writer = kHexDigits[value & 0xF];
+    value >>= 4;
+  } while (value != 0);
+
+  char* beg;
+  if (end - writer < hex.width) {
+    beg = end - hex.width;
+    std::fill_n(beg, writer - beg, hex.fill);
+  } else {
+    beg = writer;
+  }
+
+  piece_ = absl::string_view(beg, end - beg);
+}
+
+// TODO(jorg): Don't duplicate so much code between here and str_cat.cc
+Arg::Arg(Dec dec) {
+  assert(dec.width <= numbers_internal::kFastToBufferSize);
+  char* const end = &scratch_[numbers_internal::kFastToBufferSize];
+  char* const minfill = end - dec.width;
+  char* writer = end;
+  uint64_t value = dec.value;
+  bool neg = dec.neg;
+  while (value > 9) {
+    *--writer = '0' + (value % 10);
+    value /= 10;
+  }
+  *--writer = '0' + value;
+  if (neg) *--writer = '-';
+
+  ptrdiff_t fillers = writer - minfill;
+  if (fillers > 0) {
+    // Tricky: if the fill character is ' ', then it's <fill><+/-><digits>
+    // But...: if the fill character is '0', then it's <+/-><fill><digits>
+    bool add_sign_again = false;
+    if (neg && dec.fill == '0') {  // If filling with '0',
+      ++writer;                    // ignore the sign we just added
+      add_sign_again = true;       // and re-add the sign later.
+    }
+    writer -= fillers;
+    std::fill_n(writer, fillers, dec.fill);
+    if (add_sign_again) *--writer = '-';
+  }
+
+  piece_ = absl::string_view(writer, end - writer);
+}
+
+}  // namespace substitute_internal
+}  // namespace absl

http://git-wip-us.apache.org/repos/asf/marmotta/blob/0eb556da/libraries/ostrich/backend/3rdparty/abseil/absl/strings/substitute.h
----------------------------------------------------------------------
diff --git 
a/libraries/ostrich/backend/3rdparty/abseil/absl/strings/substitute.h 
b/libraries/ostrich/backend/3rdparty/abseil/absl/strings/substitute.h
new file mode 100644
index 0000000..5747d38
--- /dev/null
+++ b/libraries/ostrich/backend/3rdparty/abseil/absl/strings/substitute.h
@@ -0,0 +1,668 @@
+//
+// Copyright 2017 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
+//
+//      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.
+//
+// 
-----------------------------------------------------------------------------
+// File: substitute.h
+// 
-----------------------------------------------------------------------------
+//
+// This package contains functions for efficiently performing std::string
+// substitutions using a format std::string with positional notation:
+// `Substitute()` and `SubstituteAndAppend()`.
+//
+// Unlike printf-style format specifiers, `Substitute()` functions do not need
+// to specify the type of the substitution arguments. Supported arguments
+// following the format std::string, such as strings, string_views, ints,
+// floats, and bools, are automatically converted to strings during the
+// substitution process. (See below for a full list of supported types.)
+//
+// `Substitute()` does not allow you to specify *how* to format a value, beyond
+// the default conversion to std::string. For example, you cannot format an 
integer
+// in hex.
+//
+// The format std::string uses positional identifiers indicated by a dollar 
sign ($)
+// and single digit positional ids to indicate which substitution arguments to
+// use at that location within the format std::string.
+//
+// Example 1:
+//   std::string s = Substitute("$1 purchased $0 $2. Thanks $1!",
+//                         5, "Bob", "Apples");
+//   EXPECT_EQ("Bob purchased 5 Apples. Thanks Bob!", s);
+//
+// Example 2:
+//   std::string s = "Hi. ";
+//   SubstituteAndAppend(&s, "My name is $0 and I am $1 years old.", "Bob", 5);
+//   EXPECT_EQ("Hi. My name is Bob and I am 5 years old.", s);
+//
+//
+// Supported types:
+//   * absl::string_view, std::string, const char* (null is equivalent to "")
+//   * int32_t, int64_t, uint32_t, uint64
+//   * float, double
+//   * bool (Printed as "true" or "false")
+//   * pointer types other than char* (Printed as "0x<lower case hex 
std::string>",
+//     except that null is printed as "NULL")
+//
+// If an invalid format std::string is provided, Substitute returns an empty 
std::string
+// and SubstituteAndAppend does not change the provided output std::string.
+// A format std::string is invalid if it:
+//   * ends in an unescaped $ character,
+//     e.g. "Hello $", or
+//   * calls for a position argument which is not provided,
+//     e.g. Substitute("Hello $2", "world"), or
+//   * specifies a non-digit, non-$ character after an unescaped $ character,
+//     e.g. "Hello $f".
+// In debug mode, i.e. #ifndef NDEBUG, such errors terminate the program.
+
+#ifndef ABSL_STRINGS_SUBSTITUTE_H_
+#define ABSL_STRINGS_SUBSTITUTE_H_
+
+#include <cstring>
+#include <string>
+
+#include "absl/base/macros.h"
+#include "absl/base/port.h"
+#include "absl/strings/ascii.h"
+#include "absl/strings/escaping.h"
+#include "absl/strings/numbers.h"
+#include "absl/strings/str_cat.h"
+#include "absl/strings/str_split.h"
+#include "absl/strings/string_view.h"
+#include "absl/strings/strip.h"
+
+namespace absl {
+namespace substitute_internal {
+
+// Arg
+//
+// This class provides an argument type for `absl::Substitute()` and
+// `absl::SubstituteAndAppend()`. `Arg` handles implicit conversion of various
+// types to a std::string. (`Arg` is very similar to the `AlphaNum` class in
+// `StrCat()`.)
+//
+// This class has implicit constructors.
+class Arg {
+ public:
+  // Overloads for std::string-y things
+  //
+  // Explicitly overload `const char*` so the compiler doesn't cast to `bool`.
+  Arg(const char* value)  // NOLINT(runtime/explicit)
+      : piece_(absl::NullSafeStringView(value)) {}
+  Arg(const std::string& value)  // NOLINT(runtime/explicit)
+      : piece_(value) {}
+  Arg(absl::string_view value)  // NOLINT(runtime/explicit)
+      : piece_(value) {}
+
+  // Overloads for primitives
+  //
+  // No overloads are available for signed and unsigned char because if people
+  // are explicitly declaring their chars as signed or unsigned then they are
+  // probably using them as 8-bit integers and would probably prefer an integer
+  // representation. However, we can't really know, so we make the caller 
decide
+  // what to do.
+  Arg(char value)  // NOLINT(runtime/explicit)
+      : piece_(scratch_, 1) { scratch_[0] = value; }
+  Arg(short value)  // NOLINT(*)
+      : piece_(scratch_,
+               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) 
{}
+  Arg(unsigned short value)  // NOLINT(*)
+      : piece_(scratch_,
+               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) 
{}
+  Arg(int value)  // NOLINT(runtime/explicit)
+      : piece_(scratch_,
+               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) 
{}
+  Arg(unsigned int value)  // NOLINT(runtime/explicit)
+      : piece_(scratch_,
+               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) 
{}
+  Arg(long value)  // NOLINT(*)
+      : piece_(scratch_,
+               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) 
{}
+  Arg(unsigned long value)  // NOLINT(*)
+      : piece_(scratch_,
+               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) 
{}
+  Arg(long long value)  // NOLINT(*)
+      : piece_(scratch_,
+               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) 
{}
+  Arg(unsigned long long value)  // NOLINT(*)
+      : piece_(scratch_,
+               numbers_internal::FastIntToBuffer(value, scratch_) - scratch_) 
{}
+  Arg(float value)  // NOLINT(runtime/explicit)
+      : piece_(scratch_, numbers_internal::SixDigitsToBuffer(value, scratch_)) 
{
+  }
+  Arg(double value)  // NOLINT(runtime/explicit)
+      : piece_(scratch_, numbers_internal::SixDigitsToBuffer(value, scratch_)) 
{
+  }
+  Arg(bool value)  // NOLINT(runtime/explicit)
+      : piece_(value ? "true" : "false") {}
+
+  Arg(Hex hex);  // NOLINT(runtime/explicit)
+  Arg(Dec dec);  // NOLINT(runtime/explicit)
+
+  // `void*` values, with the exception of `char*`, are printed as
+  // "0x<hex value>". However, in the case of `nullptr`, "NULL" is printed.
+  Arg(const void* value);  // NOLINT(runtime/explicit)
+
+  Arg(const Arg&) = delete;
+  Arg& operator=(const Arg&) = delete;
+
+  absl::string_view piece() const { return piece_; }
+
+ private:
+  absl::string_view piece_;
+  char scratch_[numbers_internal::kFastToBufferSize];
+};
+
+// Internal helper function. Don't call this from outside this implementation.
+// This interface may change without notice.
+void SubstituteAndAppendArray(std::string* output, absl::string_view format,
+                              const absl::string_view* args_array,
+                              size_t num_args);
+
+#if defined(ABSL_BAD_CALL_IF)
+constexpr int CalculateOneBit(const char* format) {
+  return (*format < '0' || *format > '9') ? 0 : (1 << (*format - '0'));
+}
+
+constexpr const char* SkipNumber(const char* format) {
+  return !*format ? format : (format + 1);
+}
+
+constexpr int PlaceholderBitmask(const char* format) {
+  return !*format ? 0 : *format != '$'
+                             ? PlaceholderBitmask(format + 1)
+                             : (CalculateOneBit(format + 1) |
+                                   PlaceholderBitmask(SkipNumber(format + 1)));
+}
+#endif  // ABSL_BAD_CALL_IF
+
+}  // namespace substitute_internal
+
+//
+// PUBLIC API
+//
+
+// SubstituteAndAppend()
+//
+// Substitutes variables into a given format std::string and appends to a given
+// output std::string. See file comments above for usage.
+//
+// The declarations of `SubstituteAndAppend()` below consist of overloads
+// for passing 0 to 10 arguments, respectively.
+//
+// NOTE: A zero-argument `SubstituteAndAppend()` may be used within variadic
+// templates to allow a variable number of arguments.
+//
+// Example:
+//  template <typename... Args>
+//  void VarMsg(std::string* boilerplate, absl::string_view format,
+//      const Args&... args) {
+//    absl::SubstituteAndAppend(boilerplate, format, args...);
+//  }
+//
+inline void SubstituteAndAppend(std::string* output, absl::string_view format) 
{
+  substitute_internal::SubstituteAndAppendArray(output, format, nullptr, 0);
+}
+
+inline void SubstituteAndAppend(std::string* output, absl::string_view format,
+                                const substitute_internal::Arg& a0) {
+  const absl::string_view args[] = {a0.piece()};
+  substitute_internal::SubstituteAndAppendArray(output, format, args,
+                                                ABSL_ARRAYSIZE(args));
+}
+
+inline void SubstituteAndAppend(std::string* output, absl::string_view format,
+                                const substitute_internal::Arg& a0,
+                                const substitute_internal::Arg& a1) {
+  const absl::string_view args[] = {a0.piece(), a1.piece()};
+  substitute_internal::SubstituteAndAppendArray(output, format, args,
+                                                ABSL_ARRAYSIZE(args));
+}
+
+inline void SubstituteAndAppend(std::string* output, absl::string_view format,
+                                const substitute_internal::Arg& a0,
+                                const substitute_internal::Arg& a1,
+                                const substitute_internal::Arg& a2) {
+  const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece()};
+  substitute_internal::SubstituteAndAppendArray(output, format, args,
+                                                ABSL_ARRAYSIZE(args));
+}
+
+inline void SubstituteAndAppend(std::string* output, absl::string_view format,
+                                const substitute_internal::Arg& a0,
+                                const substitute_internal::Arg& a1,
+                                const substitute_internal::Arg& a2,
+                                const substitute_internal::Arg& a3) {
+  const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(),
+                                    a3.piece()};
+  substitute_internal::SubstituteAndAppendArray(output, format, args,
+                                                ABSL_ARRAYSIZE(args));
+}
+
+inline void SubstituteAndAppend(std::string* output, absl::string_view format,
+                                const substitute_internal::Arg& a0,
+                                const substitute_internal::Arg& a1,
+                                const substitute_internal::Arg& a2,
+                                const substitute_internal::Arg& a3,
+                                const substitute_internal::Arg& a4) {
+  const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(),
+                                    a3.piece(), a4.piece()};
+  substitute_internal::SubstituteAndAppendArray(output, format, args,
+                                                ABSL_ARRAYSIZE(args));
+}
+
+inline void SubstituteAndAppend(std::string* output, absl::string_view format,
+                                const substitute_internal::Arg& a0,
+                                const substitute_internal::Arg& a1,
+                                const substitute_internal::Arg& a2,
+                                const substitute_internal::Arg& a3,
+                                const substitute_internal::Arg& a4,
+                                const substitute_internal::Arg& a5) {
+  const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(),
+                                    a3.piece(), a4.piece(), a5.piece()};
+  substitute_internal::SubstituteAndAppendArray(output, format, args,
+                                                ABSL_ARRAYSIZE(args));
+}
+
+inline void SubstituteAndAppend(std::string* output, absl::string_view format,
+                                const substitute_internal::Arg& a0,
+                                const substitute_internal::Arg& a1,
+                                const substitute_internal::Arg& a2,
+                                const substitute_internal::Arg& a3,
+                                const substitute_internal::Arg& a4,
+                                const substitute_internal::Arg& a5,
+                                const substitute_internal::Arg& a6) {
+  const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(),
+                                    a3.piece(), a4.piece(), a5.piece(),
+                                    a6.piece()};
+  substitute_internal::SubstituteAndAppendArray(output, format, args,
+                                                ABSL_ARRAYSIZE(args));
+}
+
+inline void SubstituteAndAppend(
+    std::string* output, absl::string_view format,
+    const substitute_internal::Arg& a0, const substitute_internal::Arg& a1,
+    const substitute_internal::Arg& a2, const substitute_internal::Arg& a3,
+    const substitute_internal::Arg& a4, const substitute_internal::Arg& a5,
+    const substitute_internal::Arg& a6, const substitute_internal::Arg& a7) {
+  const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(),
+                                    a3.piece(), a4.piece(), a5.piece(),
+                                    a6.piece(), a7.piece()};
+  substitute_internal::SubstituteAndAppendArray(output, format, args,
+                                                ABSL_ARRAYSIZE(args));
+}
+
+inline void SubstituteAndAppend(
+    std::string* output, absl::string_view format,
+    const substitute_internal::Arg& a0, const substitute_internal::Arg& a1,
+    const substitute_internal::Arg& a2, const substitute_internal::Arg& a3,
+    const substitute_internal::Arg& a4, const substitute_internal::Arg& a5,
+    const substitute_internal::Arg& a6, const substitute_internal::Arg& a7,
+    const substitute_internal::Arg& a8) {
+  const absl::string_view args[] = {a0.piece(), a1.piece(), a2.piece(),
+                                    a3.piece(), a4.piece(), a5.piece(),
+                                    a6.piece(), a7.piece(), a8.piece()};
+  substitute_internal::SubstituteAndAppendArray(output, format, args,
+                                                ABSL_ARRAYSIZE(args));
+}
+
+inline void SubstituteAndAppend(
+    std::string* output, absl::string_view format,
+    const substitute_internal::Arg& a0, const substitute_internal::Arg& a1,
+    const substitute_internal::Arg& a2, const substitute_internal::Arg& a3,
+    const substitute_internal::Arg& a4, const substitute_internal::Arg& a5,
+    const substitute_internal::Arg& a6, const substitute_internal::Arg& a7,
+    const substitute_internal::Arg& a8, const substitute_internal::Arg& a9) {
+  const absl::string_view args[] = {
+      a0.piece(), a1.piece(), a2.piece(), a3.piece(), a4.piece(),
+      a5.piece(), a6.piece(), a7.piece(), a8.piece(), a9.piece()};
+  substitute_internal::SubstituteAndAppendArray(output, format, args,
+                                                ABSL_ARRAYSIZE(args));
+}
+
+#if defined(ABSL_BAD_CALL_IF)
+// This body of functions catches cases where the number of placeholders
+// doesn't match the number of data arguments.
+void SubstituteAndAppend(std::string* output, const char* format)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 0,
+                     "There were no substitution arguments "
+                     "but this format std::string has a $[0-9] in it");
+
+void SubstituteAndAppend(std::string* output, const char* format,
+                         const substitute_internal::Arg& a0)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 1,
+                     "There was 1 substitution argument given, but "
+                     "this format std::string is either missing its $0, or "
+                     "contains one of $1-$9");
+
+void SubstituteAndAppend(std::string* output, const char* format,
+                         const substitute_internal::Arg& a0,
+                         const substitute_internal::Arg& a1)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 3,
+                     "There were 2 substitution arguments given, but "
+                     "this format std::string is either missing its $0/$1, or "
+                     "contains one of $2-$9");
+
+void SubstituteAndAppend(std::string* output, const char* format,
+                         const substitute_internal::Arg& a0,
+                         const substitute_internal::Arg& a1,
+                         const substitute_internal::Arg& a2)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 7,
+                     "There were 3 substitution arguments given, but "
+                     "this format std::string is either missing its $0/$1/$2, 
or "
+                     "contains one of $3-$9");
+
+void SubstituteAndAppend(std::string* output, const char* format,
+                         const substitute_internal::Arg& a0,
+                         const substitute_internal::Arg& a1,
+                         const substitute_internal::Arg& a2,
+                         const substitute_internal::Arg& a3)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 15,
+                     "There were 4 substitution arguments given, but "
+                     "this format std::string is either missing its $0-$3, or "
+                     "contains one of $4-$9");
+
+void SubstituteAndAppend(std::string* output, const char* format,
+                         const substitute_internal::Arg& a0,
+                         const substitute_internal::Arg& a1,
+                         const substitute_internal::Arg& a2,
+                         const substitute_internal::Arg& a3,
+                         const substitute_internal::Arg& a4)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 31,
+                     "There were 5 substitution arguments given, but "
+                     "this format std::string is either missing its $0-$4, or "
+                     "contains one of $5-$9");
+
+void SubstituteAndAppend(std::string* output, const char* format,
+                         const substitute_internal::Arg& a0,
+                         const substitute_internal::Arg& a1,
+                         const substitute_internal::Arg& a2,
+                         const substitute_internal::Arg& a3,
+                         const substitute_internal::Arg& a4,
+                         const substitute_internal::Arg& a5)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 63,
+                     "There were 6 substitution arguments given, but "
+                     "this format std::string is either missing its $0-$5, or "
+                     "contains one of $6-$9");
+
+void SubstituteAndAppend(
+    std::string* output, const char* format, const substitute_internal::Arg& 
a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4,
+    const substitute_internal::Arg& a5, const substitute_internal::Arg& a6)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 127,
+                     "There were 7 substitution arguments given, but "
+                     "this format std::string is either missing its $0-$6, or "
+                     "contains one of $7-$9");
+
+void SubstituteAndAppend(
+    std::string* output, const char* format, const substitute_internal::Arg& 
a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4,
+    const substitute_internal::Arg& a5, const substitute_internal::Arg& a6,
+    const substitute_internal::Arg& a7)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 255,
+                     "There were 8 substitution arguments given, but "
+                     "this format std::string is either missing its $0-$7, or "
+                     "contains one of $8-$9");
+
+void SubstituteAndAppend(
+    std::string* output, const char* format, const substitute_internal::Arg& 
a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4,
+    const substitute_internal::Arg& a5, const substitute_internal::Arg& a6,
+    const substitute_internal::Arg& a7, const substitute_internal::Arg& a8)
+    ABSL_BAD_CALL_IF(
+        substitute_internal::PlaceholderBitmask(format) != 511,
+        "There were 9 substitution arguments given, but "
+        "this format std::string is either missing its $0-$8, or contains a 
$9");
+
+void SubstituteAndAppend(
+    std::string* output, const char* format, const substitute_internal::Arg& 
a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4,
+    const substitute_internal::Arg& a5, const substitute_internal::Arg& a6,
+    const substitute_internal::Arg& a7, const substitute_internal::Arg& a8,
+    const substitute_internal::Arg& a9)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 1023,
+                     "There were 10 substitution arguments given, but this "
+                     "format std::string doesn't contain all of $0 through 
$9");
+#endif  // ABSL_BAD_CALL_IF
+
+// Substitute()
+//
+// Substitutes variables into a given format std::string. See file comments 
above
+// for usage.
+//
+// The declarations of `Substitute()` below consist of overloads for passing 0
+// to 10 arguments, respectively.
+//
+// NOTE: A zero-argument `Substitute()` may be used within variadic templates 
to
+// allow a variable number of arguments.
+//
+// Example:
+//  template <typename... Args>
+//  void VarMsg(absl::string_view format, const Args&... args) {
+//    std::string s = absl::Substitute(format, args...);
+
+ABSL_MUST_USE_RESULT inline std::string Substitute(absl::string_view format) {
+  std::string result;
+  SubstituteAndAppend(&result, format);
+  return result;
+}
+
+ABSL_MUST_USE_RESULT inline std::string Substitute(
+    absl::string_view format, const substitute_internal::Arg& a0) {
+  std::string result;
+  SubstituteAndAppend(&result, format, a0);
+  return result;
+}
+
+ABSL_MUST_USE_RESULT inline std::string Substitute(
+    absl::string_view format, const substitute_internal::Arg& a0,
+    const substitute_internal::Arg& a1) {
+  std::string result;
+  SubstituteAndAppend(&result, format, a0, a1);
+  return result;
+}
+
+ABSL_MUST_USE_RESULT inline std::string Substitute(
+    absl::string_view format, const substitute_internal::Arg& a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2) {
+  std::string result;
+  SubstituteAndAppend(&result, format, a0, a1, a2);
+  return result;
+}
+
+ABSL_MUST_USE_RESULT inline std::string Substitute(
+    absl::string_view format, const substitute_internal::Arg& a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3) {
+  std::string result;
+  SubstituteAndAppend(&result, format, a0, a1, a2, a3);
+  return result;
+}
+
+ABSL_MUST_USE_RESULT inline std::string Substitute(
+    absl::string_view format, const substitute_internal::Arg& a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4) {
+  std::string result;
+  SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4);
+  return result;
+}
+
+ABSL_MUST_USE_RESULT inline std::string Substitute(
+    absl::string_view format, const substitute_internal::Arg& a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4,
+    const substitute_internal::Arg& a5) {
+  std::string result;
+  SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4, a5);
+  return result;
+}
+
+ABSL_MUST_USE_RESULT inline std::string Substitute(
+    absl::string_view format, const substitute_internal::Arg& a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4,
+    const substitute_internal::Arg& a5, const substitute_internal::Arg& a6) {
+  std::string result;
+  SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4, a5, a6);
+  return result;
+}
+
+ABSL_MUST_USE_RESULT inline std::string Substitute(
+    absl::string_view format, const substitute_internal::Arg& a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4,
+    const substitute_internal::Arg& a5, const substitute_internal::Arg& a6,
+    const substitute_internal::Arg& a7) {
+  std::string result;
+  SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4, a5, a6, a7);
+  return result;
+}
+
+ABSL_MUST_USE_RESULT inline std::string Substitute(
+    absl::string_view format, const substitute_internal::Arg& a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4,
+    const substitute_internal::Arg& a5, const substitute_internal::Arg& a6,
+    const substitute_internal::Arg& a7, const substitute_internal::Arg& a8) {
+  std::string result;
+  SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4, a5, a6, a7, a8);
+  return result;
+}
+
+ABSL_MUST_USE_RESULT inline std::string Substitute(
+    absl::string_view format, const substitute_internal::Arg& a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4,
+    const substitute_internal::Arg& a5, const substitute_internal::Arg& a6,
+    const substitute_internal::Arg& a7, const substitute_internal::Arg& a8,
+    const substitute_internal::Arg& a9) {
+  std::string result;
+  SubstituteAndAppend(&result, format, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9);
+  return result;
+}
+
+#if defined(ABSL_BAD_CALL_IF)
+// This body of functions catches cases where the number of placeholders
+// doesn't match the number of data arguments.
+std::string Substitute(const char* format)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 0,
+                     "There were no substitution arguments "
+                     "but this format std::string has a $[0-9] in it");
+
+std::string Substitute(const char* format, const substitute_internal::Arg& a0)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 1,
+                     "There was 1 substitution argument given, but "
+                     "this format std::string is either missing its $0, or "
+                     "contains one of $1-$9");
+
+std::string Substitute(const char* format, const substitute_internal::Arg& a0,
+                  const substitute_internal::Arg& a1)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 3,
+                     "There were 2 substitution arguments given, but "
+                     "this format std::string is either missing its $0/$1, or "
+                     "contains one of $2-$9");
+
+std::string Substitute(const char* format, const substitute_internal::Arg& a0,
+                  const substitute_internal::Arg& a1,
+                  const substitute_internal::Arg& a2)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 7,
+                     "There were 3 substitution arguments given, but "
+                     "this format std::string is either missing its $0/$1/$2, 
or "
+                     "contains one of $3-$9");
+
+std::string Substitute(const char* format, const substitute_internal::Arg& a0,
+                  const substitute_internal::Arg& a1,
+                  const substitute_internal::Arg& a2,
+                  const substitute_internal::Arg& a3)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 15,
+                     "There were 4 substitution arguments given, but "
+                     "this format std::string is either missing its $0-$3, or "
+                     "contains one of $4-$9");
+
+std::string Substitute(const char* format, const substitute_internal::Arg& a0,
+                  const substitute_internal::Arg& a1,
+                  const substitute_internal::Arg& a2,
+                  const substitute_internal::Arg& a3,
+                  const substitute_internal::Arg& a4)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 31,
+                     "There were 5 substitution arguments given, but "
+                     "this format std::string is either missing its $0-$4, or "
+                     "contains one of $5-$9");
+
+std::string Substitute(const char* format, const substitute_internal::Arg& a0,
+                  const substitute_internal::Arg& a1,
+                  const substitute_internal::Arg& a2,
+                  const substitute_internal::Arg& a3,
+                  const substitute_internal::Arg& a4,
+                  const substitute_internal::Arg& a5)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 63,
+                     "There were 6 substitution arguments given, but "
+                     "this format std::string is either missing its $0-$5, or "
+                     "contains one of $6-$9");
+
+std::string Substitute(const char* format, const substitute_internal::Arg& a0,
+                  const substitute_internal::Arg& a1,
+                  const substitute_internal::Arg& a2,
+                  const substitute_internal::Arg& a3,
+                  const substitute_internal::Arg& a4,
+                  const substitute_internal::Arg& a5,
+                  const substitute_internal::Arg& a6)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 127,
+                     "There were 7 substitution arguments given, but "
+                     "this format std::string is either missing its $0-$6, or "
+                     "contains one of $7-$9");
+
+std::string Substitute(const char* format, const substitute_internal::Arg& a0,
+                  const substitute_internal::Arg& a1,
+                  const substitute_internal::Arg& a2,
+                  const substitute_internal::Arg& a3,
+                  const substitute_internal::Arg& a4,
+                  const substitute_internal::Arg& a5,
+                  const substitute_internal::Arg& a6,
+                  const substitute_internal::Arg& a7)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 255,
+                     "There were 8 substitution arguments given, but "
+                     "this format std::string is either missing its $0-$7, or "
+                     "contains one of $8-$9");
+
+std::string Substitute(
+    const char* format, const substitute_internal::Arg& a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4,
+    const substitute_internal::Arg& a5, const substitute_internal::Arg& a6,
+    const substitute_internal::Arg& a7, const substitute_internal::Arg& a8)
+    ABSL_BAD_CALL_IF(
+        substitute_internal::PlaceholderBitmask(format) != 511,
+        "There were 9 substitution arguments given, but "
+        "this format std::string is either missing its $0-$8, or contains a 
$9");
+
+std::string Substitute(
+    const char* format, const substitute_internal::Arg& a0,
+    const substitute_internal::Arg& a1, const substitute_internal::Arg& a2,
+    const substitute_internal::Arg& a3, const substitute_internal::Arg& a4,
+    const substitute_internal::Arg& a5, const substitute_internal::Arg& a6,
+    const substitute_internal::Arg& a7, const substitute_internal::Arg& a8,
+    const substitute_internal::Arg& a9)
+    ABSL_BAD_CALL_IF(substitute_internal::PlaceholderBitmask(format) != 1023,
+                     "There were 10 substitution arguments given, but this "
+                     "format std::string doesn't contain all of $0 through 
$9");
+#endif  // ABSL_BAD_CALL_IF
+
+}  // namespace absl
+
+#endif  // ABSL_STRINGS_SUBSTITUTE_H_

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