1 // Copyright 2017 The Abseil Authors.
2 //
3 // Licensed under the Apache License, Version 2.0 (the "License");
4 // you may not use this file except in compliance with the License.
5 // You may obtain a copy of the License at
6 //
7 //      https://www.apache.org/licenses/LICENSE-2.0
8 //
9 // Unless required by applicable law or agreed to in writing, software
10 // distributed under the License is distributed on an "AS IS" BASIS,
11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 // See the License for the specific language governing permissions and
13 // limitations under the License.
14 
15 #include "absl/strings/string_view.h"
16 
17 #include <stdlib.h>
18 #include <iomanip>
19 #include <iterator>
20 #include <limits>
21 #include <map>
22 #include <sstream>
23 #include <stdexcept>
24 #include <string>
25 #include <type_traits>
26 #include <utility>
27 
28 #include "gtest/gtest.h"
29 #include "absl/base/config.h"
30 #include "absl/base/dynamic_annotations.h"
31 #include "absl/base/options.h"
32 
33 #if defined(ABSL_HAVE_STD_STRING_VIEW) || defined(__ANDROID__)
34 // We don't control the death messaging when using std::string_view.
35 // Android assert messages only go to system log, so death tests cannot inspect
36 // the message for matching.
37 #define ABSL_EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
38   EXPECT_DEATH_IF_SUPPORTED(statement, ".*")
39 #else
40 #define ABSL_EXPECT_DEATH_IF_SUPPORTED(statement, regex) \
41   EXPECT_DEATH_IF_SUPPORTED(statement, regex)
42 #endif
43 
44 namespace {
45 
46 // A minimal allocator that uses malloc().
47 template <typename T>
48 struct Mallocator {
49   typedef T value_type;
50   typedef size_t size_type;
51   typedef ptrdiff_t difference_type;
52   typedef T* pointer;
53   typedef const T* const_pointer;
54   typedef T& reference;
55   typedef const T& const_reference;
56 
max_size__anon8537586a0111::Mallocator57   size_type max_size() const {
58     return size_t(std::numeric_limits<size_type>::max()) / sizeof(value_type);
59   }
60   template <typename U>
61   struct rebind {
62     typedef Mallocator<U> other;
63   };
64   Mallocator() = default;
65   template <class U>
Mallocator__anon8537586a0111::Mallocator66   Mallocator(const Mallocator<U>&) {}  // NOLINT(runtime/explicit)
67 
allocate__anon8537586a0111::Mallocator68   T* allocate(size_t n) { return static_cast<T*>(std::malloc(n * sizeof(T))); }
deallocate__anon8537586a0111::Mallocator69   void deallocate(T* p, size_t) { std::free(p); }
70 };
71 template <typename T, typename U>
operator ==(const Mallocator<T> &,const Mallocator<U> &)72 bool operator==(const Mallocator<T>&, const Mallocator<U>&) {
73   return true;
74 }
75 template <typename T, typename U>
operator !=(const Mallocator<T> &,const Mallocator<U> &)76 bool operator!=(const Mallocator<T>&, const Mallocator<U>&) {
77   return false;
78 }
79 
TEST(StringViewTest,Ctor)80 TEST(StringViewTest, Ctor) {
81   {
82     // Null.
83     absl::string_view s10;
84     EXPECT_TRUE(s10.data() == nullptr);
85     EXPECT_EQ(0u, s10.length());
86   }
87 
88   {
89     // const char* without length.
90     const char* hello = "hello";
91     absl::string_view s20(hello);
92     EXPECT_TRUE(s20.data() == hello);
93     EXPECT_EQ(5u, s20.length());
94 
95     // const char* with length.
96     absl::string_view s21(hello, 4);
97     EXPECT_TRUE(s21.data() == hello);
98     EXPECT_EQ(4u, s21.length());
99 
100     // Not recommended, but valid C++
101     absl::string_view s22(hello, 6);
102     EXPECT_TRUE(s22.data() == hello);
103     EXPECT_EQ(6u, s22.length());
104   }
105 
106   {
107     // std::string.
108     std::string hola = "hola";
109     absl::string_view s30(hola);
110     EXPECT_TRUE(s30.data() == hola.data());
111     EXPECT_EQ(4u, s30.length());
112 
113     // std::string with embedded '\0'.
114     hola.push_back('\0');
115     hola.append("h2");
116     hola.push_back('\0');
117     absl::string_view s31(hola);
118     EXPECT_TRUE(s31.data() == hola.data());
119     EXPECT_EQ(8u, s31.length());
120   }
121 
122   {
123     using mstring =
124         std::basic_string<char, std::char_traits<char>, Mallocator<char>>;
125     mstring str1("BUNGIE-JUMPING!");
126     const mstring str2("SLEEPING!");
127 
128     absl::string_view s1(str1);
129     s1.remove_prefix(strlen("BUNGIE-JUM"));
130 
131     absl::string_view s2(str2);
132     s2.remove_prefix(strlen("SLEE"));
133 
134     EXPECT_EQ(s1, s2);
135     EXPECT_EQ(s1, "PING!");
136   }
137 
138   // TODO(mec): absl::string_view(const absl::string_view&);
139 }
140 
TEST(StringViewTest,Swap)141 TEST(StringViewTest, Swap) {
142   absl::string_view a("a");
143   absl::string_view b("bbb");
144   EXPECT_TRUE(noexcept(a.swap(b)));
145   a.swap(b);
146   EXPECT_EQ(a, "bbb");
147   EXPECT_EQ(b, "a");
148   a.swap(b);
149   EXPECT_EQ(a, "a");
150   EXPECT_EQ(b, "bbb");
151 }
152 
TEST(StringViewTest,STLComparator)153 TEST(StringViewTest, STLComparator) {
154   std::string s1("foo");
155   std::string s2("bar");
156   std::string s3("baz");
157 
158   absl::string_view p1(s1);
159   absl::string_view p2(s2);
160   absl::string_view p3(s3);
161 
162   typedef std::map<absl::string_view, int> TestMap;
163   TestMap map;
164 
165   map.insert(std::make_pair(p1, 0));
166   map.insert(std::make_pair(p2, 1));
167   map.insert(std::make_pair(p3, 2));
168   EXPECT_EQ(map.size(), 3u);
169 
170   TestMap::const_iterator iter = map.begin();
171   EXPECT_EQ(iter->second, 1);
172   ++iter;
173   EXPECT_EQ(iter->second, 2);
174   ++iter;
175   EXPECT_EQ(iter->second, 0);
176   ++iter;
177   EXPECT_TRUE(iter == map.end());
178 
179   TestMap::iterator new_iter = map.find("zot");
180   EXPECT_TRUE(new_iter == map.end());
181 
182   new_iter = map.find("bar");
183   EXPECT_TRUE(new_iter != map.end());
184 
185   map.erase(new_iter);
186   EXPECT_EQ(map.size(), 2u);
187 
188   iter = map.begin();
189   EXPECT_EQ(iter->second, 2);
190   ++iter;
191   EXPECT_EQ(iter->second, 0);
192   ++iter;
193   EXPECT_TRUE(iter == map.end());
194 }
195 
196 #define COMPARE(result, op, x, y)                                      \
197   EXPECT_EQ(result, absl::string_view((x)) op absl::string_view((y))); \
198   EXPECT_EQ(result, absl::string_view((x)).compare(absl::string_view((y))) op 0)
199 
TEST(StringViewTest,ComparisonOperators)200 TEST(StringViewTest, ComparisonOperators) {
201   COMPARE(true, ==, "",   "");
202   COMPARE(true, ==, "", absl::string_view());
203   COMPARE(true, ==, absl::string_view(), "");
204   COMPARE(true, ==, "a",  "a");
205   COMPARE(true, ==, "aa", "aa");
206   COMPARE(false, ==, "a",  "");
207   COMPARE(false, ==, "",   "a");
208   COMPARE(false, ==, "a",  "b");
209   COMPARE(false, ==, "a",  "aa");
210   COMPARE(false, ==, "aa", "a");
211 
212   COMPARE(false, !=, "",   "");
213   COMPARE(false, !=, "a",  "a");
214   COMPARE(false, !=, "aa", "aa");
215   COMPARE(true, !=, "a",  "");
216   COMPARE(true, !=, "",   "a");
217   COMPARE(true, !=, "a",  "b");
218   COMPARE(true, !=, "a",  "aa");
219   COMPARE(true, !=, "aa", "a");
220 
221   COMPARE(true, <, "a",  "b");
222   COMPARE(true, <, "a",  "aa");
223   COMPARE(true, <, "aa", "b");
224   COMPARE(true, <, "aa", "bb");
225   COMPARE(false, <, "a",  "a");
226   COMPARE(false, <, "b",  "a");
227   COMPARE(false, <, "aa", "a");
228   COMPARE(false, <, "b",  "aa");
229   COMPARE(false, <, "bb", "aa");
230 
231   COMPARE(true, <=, "a",  "a");
232   COMPARE(true, <=, "a",  "b");
233   COMPARE(true, <=, "a",  "aa");
234   COMPARE(true, <=, "aa", "b");
235   COMPARE(true, <=, "aa", "bb");
236   COMPARE(false, <=, "b",  "a");
237   COMPARE(false, <=, "aa", "a");
238   COMPARE(false, <=, "b",  "aa");
239   COMPARE(false, <=, "bb", "aa");
240 
241   COMPARE(false, >=, "a",  "b");
242   COMPARE(false, >=, "a",  "aa");
243   COMPARE(false, >=, "aa", "b");
244   COMPARE(false, >=, "aa", "bb");
245   COMPARE(true, >=, "a",  "a");
246   COMPARE(true, >=, "b",  "a");
247   COMPARE(true, >=, "aa", "a");
248   COMPARE(true, >=, "b",  "aa");
249   COMPARE(true, >=, "bb", "aa");
250 
251   COMPARE(false, >, "a",  "a");
252   COMPARE(false, >, "a",  "b");
253   COMPARE(false, >, "a",  "aa");
254   COMPARE(false, >, "aa", "b");
255   COMPARE(false, >, "aa", "bb");
256   COMPARE(true, >, "b",  "a");
257   COMPARE(true, >, "aa", "a");
258   COMPARE(true, >, "b",  "aa");
259   COMPARE(true, >, "bb", "aa");
260 }
261 
TEST(StringViewTest,ComparisonOperatorsByCharacterPosition)262 TEST(StringViewTest, ComparisonOperatorsByCharacterPosition) {
263   std::string x;
264   for (size_t i = 0; i < 256; i++) {
265     x += 'a';
266     std::string y = x;
267     COMPARE(true, ==, x, y);
268     for (size_t j = 0; j < i; j++) {
269       std::string z = x;
270       z[j] = 'b';       // Differs in position 'j'
271       COMPARE(false, ==, x, z);
272       COMPARE(true, <, x, z);
273       COMPARE(true, >, z, x);
274       if (j + 1 < i) {
275         z[j + 1] = 'A';  // Differs in position 'j+1' as well
276         COMPARE(false, ==, x, z);
277         COMPARE(true, <, x, z);
278         COMPARE(true, >, z, x);
279         z[j + 1] = 'z';  // Differs in position 'j+1' as well
280         COMPARE(false, ==, x, z);
281         COMPARE(true, <, x, z);
282         COMPARE(true, >, z, x);
283       }
284     }
285   }
286 }
287 #undef COMPARE
288 
289 // Sadly, our users often confuse std::string::npos with
290 // absl::string_view::npos; So much so that we test here that they are the same.
291 // They need to both be unsigned, and both be the maximum-valued integer of
292 // their type.
293 
294 template <typename T>
295 struct is_type {
296   template <typename U>
same__anon8537586a0111::is_type297   static bool same(U) {
298     return false;
299   }
same__anon8537586a0111::is_type300   static bool same(T) { return true; }
301 };
302 
TEST(StringViewTest,NposMatchesStdStringView)303 TEST(StringViewTest, NposMatchesStdStringView) {
304   EXPECT_EQ(absl::string_view::npos, std::string::npos);
305 
306   EXPECT_TRUE(is_type<size_t>::same(absl::string_view::npos));
307   EXPECT_FALSE(is_type<size_t>::same(""));
308 
309   // Make sure absl::string_view::npos continues to be a header constant.
310   char test[absl::string_view::npos & 1] = {0};
311   EXPECT_EQ(0, test[0]);
312 }
313 
TEST(StringViewTest,STL1)314 TEST(StringViewTest, STL1) {
315   const absl::string_view a("abcdefghijklmnopqrstuvwxyz");
316   const absl::string_view b("abc");
317   const absl::string_view c("xyz");
318   const absl::string_view d("foobar");
319   const absl::string_view e;
320   std::string temp("123");
321   temp += '\0';
322   temp += "456";
323   const absl::string_view f(temp);
324 
325   EXPECT_EQ(a[6], 'g');
326   EXPECT_EQ(b[0], 'a');
327   EXPECT_EQ(c[2], 'z');
328   EXPECT_EQ(f[3], '\0');
329   EXPECT_EQ(f[5], '5');
330 
331   EXPECT_EQ(*d.data(), 'f');
332   EXPECT_EQ(d.data()[5], 'r');
333   EXPECT_TRUE(e.data() == nullptr);
334 
335   EXPECT_EQ(*a.begin(), 'a');
336   EXPECT_EQ(*(b.begin() + 2), 'c');
337   EXPECT_EQ(*(c.end() - 1), 'z');
338 
339   EXPECT_EQ(*a.rbegin(), 'z');
340   EXPECT_EQ(*(b.rbegin() + 2), 'a');
341   EXPECT_EQ(*(c.rend() - 1), 'x');
342   EXPECT_TRUE(a.rbegin() + 26 == a.rend());
343 
344   EXPECT_EQ(a.size(), 26u);
345   EXPECT_EQ(b.size(), 3u);
346   EXPECT_EQ(c.size(), 3u);
347   EXPECT_EQ(d.size(), 6u);
348   EXPECT_EQ(e.size(), 0u);
349   EXPECT_EQ(f.size(), 7u);
350 
351   EXPECT_TRUE(!d.empty());
352   EXPECT_TRUE(d.begin() != d.end());
353   EXPECT_TRUE(d.begin() + 6 == d.end());
354 
355   EXPECT_TRUE(e.empty());
356   EXPECT_TRUE(e.begin() == e.end());
357 
358   char buf[4] = { '%', '%', '%', '%' };
359   EXPECT_EQ(a.copy(buf, 4), 4u);
360   EXPECT_EQ(buf[0], a[0]);
361   EXPECT_EQ(buf[1], a[1]);
362   EXPECT_EQ(buf[2], a[2]);
363   EXPECT_EQ(buf[3], a[3]);
364   EXPECT_EQ(a.copy(buf, 3, 7), 3u);
365   EXPECT_EQ(buf[0], a[7]);
366   EXPECT_EQ(buf[1], a[8]);
367   EXPECT_EQ(buf[2], a[9]);
368   EXPECT_EQ(buf[3], a[3]);
369   EXPECT_EQ(c.copy(buf, 99), 3u);
370   EXPECT_EQ(buf[0], c[0]);
371   EXPECT_EQ(buf[1], c[1]);
372   EXPECT_EQ(buf[2], c[2]);
373   EXPECT_EQ(buf[3], a[3]);
374 #ifdef ABSL_HAVE_EXCEPTIONS
375   EXPECT_THROW(a.copy(buf, 1, 27), std::out_of_range);
376 #else
377   ABSL_EXPECT_DEATH_IF_SUPPORTED(a.copy(buf, 1, 27), "absl::string_view::copy");
378 #endif
379 }
380 
381 // Separated from STL1() because some compilers produce an overly
382 // large stack frame for the combined function.
TEST(StringViewTest,STL2)383 TEST(StringViewTest, STL2) {
384   const absl::string_view a("abcdefghijklmnopqrstuvwxyz");
385   const absl::string_view b("abc");
386   const absl::string_view c("xyz");
387   absl::string_view d("foobar");
388   const absl::string_view e;
389   const absl::string_view f(
390       "123"
391       "\0"
392       "456",
393       7);
394 
395   d = absl::string_view();
396   EXPECT_EQ(d.size(), 0u);
397   EXPECT_TRUE(d.empty());
398   EXPECT_TRUE(d.data() == nullptr);
399   EXPECT_TRUE(d.begin() == d.end());
400 
401   EXPECT_EQ(a.find(b), 0u);
402   EXPECT_EQ(a.find(b, 1), absl::string_view::npos);
403   EXPECT_EQ(a.find(c), 23u);
404   EXPECT_EQ(a.find(c, 9), 23u);
405   EXPECT_EQ(a.find(c, absl::string_view::npos), absl::string_view::npos);
406   EXPECT_EQ(b.find(c), absl::string_view::npos);
407   EXPECT_EQ(b.find(c, absl::string_view::npos), absl::string_view::npos);
408   EXPECT_EQ(a.find(d), 0u);
409   EXPECT_EQ(a.find(e), 0u);
410   EXPECT_EQ(a.find(d, 12), 12u);
411   EXPECT_EQ(a.find(e, 17), 17u);
412   absl::string_view g("xx not found bb");
413   EXPECT_EQ(a.find(g), absl::string_view::npos);
414   // empty string nonsense
415   EXPECT_EQ(d.find(b), absl::string_view::npos);
416   EXPECT_EQ(e.find(b), absl::string_view::npos);
417   EXPECT_EQ(d.find(b, 4), absl::string_view::npos);
418   EXPECT_EQ(e.find(b, 7), absl::string_view::npos);
419 
420   size_t empty_search_pos = std::string().find(std::string());
421   EXPECT_EQ(d.find(d), empty_search_pos);
422   EXPECT_EQ(d.find(e), empty_search_pos);
423   EXPECT_EQ(e.find(d), empty_search_pos);
424   EXPECT_EQ(e.find(e), empty_search_pos);
425   EXPECT_EQ(d.find(d, 4), std::string().find(std::string(), 4));
426   EXPECT_EQ(d.find(e, 4), std::string().find(std::string(), 4));
427   EXPECT_EQ(e.find(d, 4), std::string().find(std::string(), 4));
428   EXPECT_EQ(e.find(e, 4), std::string().find(std::string(), 4));
429 
430   EXPECT_EQ(a.find('a'), 0u);
431   EXPECT_EQ(a.find('c'), 2u);
432   EXPECT_EQ(a.find('z'), 25u);
433   EXPECT_EQ(a.find('$'), absl::string_view::npos);
434   EXPECT_EQ(a.find('\0'), absl::string_view::npos);
435   EXPECT_EQ(f.find('\0'), 3u);
436   EXPECT_EQ(f.find('3'), 2u);
437   EXPECT_EQ(f.find('5'), 5u);
438   EXPECT_EQ(g.find('o'), 4u);
439   EXPECT_EQ(g.find('o', 4), 4u);
440   EXPECT_EQ(g.find('o', 5), 8u);
441   EXPECT_EQ(a.find('b', 5), absl::string_view::npos);
442   // empty string nonsense
443   EXPECT_EQ(d.find('\0'), absl::string_view::npos);
444   EXPECT_EQ(e.find('\0'), absl::string_view::npos);
445   EXPECT_EQ(d.find('\0', 4), absl::string_view::npos);
446   EXPECT_EQ(e.find('\0', 7), absl::string_view::npos);
447   EXPECT_EQ(d.find('x'), absl::string_view::npos);
448   EXPECT_EQ(e.find('x'), absl::string_view::npos);
449   EXPECT_EQ(d.find('x', 4), absl::string_view::npos);
450   EXPECT_EQ(e.find('x', 7), absl::string_view::npos);
451 
452   EXPECT_EQ(a.find(b.data(), 1, 0), 1u);
453   EXPECT_EQ(a.find(c.data(), 9, 0), 9u);
454   EXPECT_EQ(a.find(c.data(), absl::string_view::npos, 0),
455             absl::string_view::npos);
456   EXPECT_EQ(b.find(c.data(), absl::string_view::npos, 0),
457             absl::string_view::npos);
458   // empty string nonsense
459   EXPECT_EQ(d.find(b.data(), 4, 0), absl::string_view::npos);
460   EXPECT_EQ(e.find(b.data(), 7, 0), absl::string_view::npos);
461 
462   EXPECT_EQ(a.find(b.data(), 1), absl::string_view::npos);
463   EXPECT_EQ(a.find(c.data(), 9), 23u);
464   EXPECT_EQ(a.find(c.data(), absl::string_view::npos), absl::string_view::npos);
465   EXPECT_EQ(b.find(c.data(), absl::string_view::npos), absl::string_view::npos);
466   // empty string nonsense
467   EXPECT_EQ(d.find(b.data(), 4), absl::string_view::npos);
468   EXPECT_EQ(e.find(b.data(), 7), absl::string_view::npos);
469 
470   EXPECT_EQ(a.rfind(b), 0u);
471   EXPECT_EQ(a.rfind(b, 1), 0u);
472   EXPECT_EQ(a.rfind(c), 23u);
473   EXPECT_EQ(a.rfind(c, 22), absl::string_view::npos);
474   EXPECT_EQ(a.rfind(c, 1), absl::string_view::npos);
475   EXPECT_EQ(a.rfind(c, 0), absl::string_view::npos);
476   EXPECT_EQ(b.rfind(c), absl::string_view::npos);
477   EXPECT_EQ(b.rfind(c, 0), absl::string_view::npos);
478   EXPECT_EQ(a.rfind(d), std::string(a).rfind(std::string()));
479   EXPECT_EQ(a.rfind(e), std::string(a).rfind(std::string()));
480   EXPECT_EQ(a.rfind(d, 12), 12u);
481   EXPECT_EQ(a.rfind(e, 17), 17u);
482   EXPECT_EQ(a.rfind(g), absl::string_view::npos);
483   EXPECT_EQ(d.rfind(b), absl::string_view::npos);
484   EXPECT_EQ(e.rfind(b), absl::string_view::npos);
485   EXPECT_EQ(d.rfind(b, 4), absl::string_view::npos);
486   EXPECT_EQ(e.rfind(b, 7), absl::string_view::npos);
487   // empty string nonsense
488   EXPECT_EQ(d.rfind(d, 4), std::string().rfind(std::string()));
489   EXPECT_EQ(e.rfind(d, 7), std::string().rfind(std::string()));
490   EXPECT_EQ(d.rfind(e, 4), std::string().rfind(std::string()));
491   EXPECT_EQ(e.rfind(e, 7), std::string().rfind(std::string()));
492   EXPECT_EQ(d.rfind(d), std::string().rfind(std::string()));
493   EXPECT_EQ(e.rfind(d), std::string().rfind(std::string()));
494   EXPECT_EQ(d.rfind(e), std::string().rfind(std::string()));
495   EXPECT_EQ(e.rfind(e), std::string().rfind(std::string()));
496 
497   EXPECT_EQ(g.rfind('o'), 8u);
498   EXPECT_EQ(g.rfind('q'), absl::string_view::npos);
499   EXPECT_EQ(g.rfind('o', 8), 8u);
500   EXPECT_EQ(g.rfind('o', 7), 4u);
501   EXPECT_EQ(g.rfind('o', 3), absl::string_view::npos);
502   EXPECT_EQ(f.rfind('\0'), 3u);
503   EXPECT_EQ(f.rfind('\0', 12), 3u);
504   EXPECT_EQ(f.rfind('3'), 2u);
505   EXPECT_EQ(f.rfind('5'), 5u);
506   // empty string nonsense
507   EXPECT_EQ(d.rfind('o'), absl::string_view::npos);
508   EXPECT_EQ(e.rfind('o'), absl::string_view::npos);
509   EXPECT_EQ(d.rfind('o', 4), absl::string_view::npos);
510   EXPECT_EQ(e.rfind('o', 7), absl::string_view::npos);
511 
512   EXPECT_EQ(a.rfind(b.data(), 1, 0), 1u);
513   EXPECT_EQ(a.rfind(c.data(), 22, 0), 22u);
514   EXPECT_EQ(a.rfind(c.data(), 1, 0), 1u);
515   EXPECT_EQ(a.rfind(c.data(), 0, 0), 0u);
516   EXPECT_EQ(b.rfind(c.data(), 0, 0), 0u);
517   EXPECT_EQ(d.rfind(b.data(), 4, 0), 0u);
518   EXPECT_EQ(e.rfind(b.data(), 7, 0), 0u);
519 }
520 
521 // Continued from STL2
TEST(StringViewTest,STL2FindFirst)522 TEST(StringViewTest, STL2FindFirst) {
523   const absl::string_view a("abcdefghijklmnopqrstuvwxyz");
524   const absl::string_view b("abc");
525   const absl::string_view c("xyz");
526   absl::string_view d("foobar");
527   const absl::string_view e;
528   const absl::string_view f(
529       "123"
530       "\0"
531       "456",
532       7);
533   absl::string_view g("xx not found bb");
534 
535   d = absl::string_view();
536   EXPECT_EQ(a.find_first_of(b), 0u);
537   EXPECT_EQ(a.find_first_of(b, 0), 0u);
538   EXPECT_EQ(a.find_first_of(b, 1), 1u);
539   EXPECT_EQ(a.find_first_of(b, 2), 2u);
540   EXPECT_EQ(a.find_first_of(b, 3), absl::string_view::npos);
541   EXPECT_EQ(a.find_first_of(c), 23u);
542   EXPECT_EQ(a.find_first_of(c, 23), 23u);
543   EXPECT_EQ(a.find_first_of(c, 24), 24u);
544   EXPECT_EQ(a.find_first_of(c, 25), 25u);
545   EXPECT_EQ(a.find_first_of(c, 26), absl::string_view::npos);
546   EXPECT_EQ(g.find_first_of(b), 13u);
547   EXPECT_EQ(g.find_first_of(c), 0u);
548   EXPECT_EQ(a.find_first_of(f), absl::string_view::npos);
549   EXPECT_EQ(f.find_first_of(a), absl::string_view::npos);
550   // empty string nonsense
551   EXPECT_EQ(a.find_first_of(d), absl::string_view::npos);
552   EXPECT_EQ(a.find_first_of(e), absl::string_view::npos);
553   EXPECT_EQ(d.find_first_of(b), absl::string_view::npos);
554   EXPECT_EQ(e.find_first_of(b), absl::string_view::npos);
555   EXPECT_EQ(d.find_first_of(d), absl::string_view::npos);
556   EXPECT_EQ(e.find_first_of(d), absl::string_view::npos);
557   EXPECT_EQ(d.find_first_of(e), absl::string_view::npos);
558   EXPECT_EQ(e.find_first_of(e), absl::string_view::npos);
559 
560   EXPECT_EQ(a.find_first_not_of(b), 3u);
561   EXPECT_EQ(a.find_first_not_of(c), 0u);
562   EXPECT_EQ(b.find_first_not_of(a), absl::string_view::npos);
563   EXPECT_EQ(c.find_first_not_of(a), absl::string_view::npos);
564   EXPECT_EQ(f.find_first_not_of(a), 0u);
565   EXPECT_EQ(a.find_first_not_of(f), 0u);
566   EXPECT_EQ(a.find_first_not_of(d), 0u);
567   EXPECT_EQ(a.find_first_not_of(e), 0u);
568   // empty string nonsense
569   EXPECT_EQ(a.find_first_not_of(d), 0u);
570   EXPECT_EQ(a.find_first_not_of(e), 0u);
571   EXPECT_EQ(a.find_first_not_of(d, 1), 1u);
572   EXPECT_EQ(a.find_first_not_of(e, 1), 1u);
573   EXPECT_EQ(a.find_first_not_of(d, a.size() - 1), a.size() - 1);
574   EXPECT_EQ(a.find_first_not_of(e, a.size() - 1), a.size() - 1);
575   EXPECT_EQ(a.find_first_not_of(d, a.size()), absl::string_view::npos);
576   EXPECT_EQ(a.find_first_not_of(e, a.size()), absl::string_view::npos);
577   EXPECT_EQ(a.find_first_not_of(d, absl::string_view::npos),
578             absl::string_view::npos);
579   EXPECT_EQ(a.find_first_not_of(e, absl::string_view::npos),
580             absl::string_view::npos);
581   EXPECT_EQ(d.find_first_not_of(a), absl::string_view::npos);
582   EXPECT_EQ(e.find_first_not_of(a), absl::string_view::npos);
583   EXPECT_EQ(d.find_first_not_of(d), absl::string_view::npos);
584   EXPECT_EQ(e.find_first_not_of(d), absl::string_view::npos);
585   EXPECT_EQ(d.find_first_not_of(e), absl::string_view::npos);
586   EXPECT_EQ(e.find_first_not_of(e), absl::string_view::npos);
587 
588   absl::string_view h("====");
589   EXPECT_EQ(h.find_first_not_of('='), absl::string_view::npos);
590   EXPECT_EQ(h.find_first_not_of('=', 3), absl::string_view::npos);
591   EXPECT_EQ(h.find_first_not_of('\0'), 0u);
592   EXPECT_EQ(g.find_first_not_of('x'), 2u);
593   EXPECT_EQ(f.find_first_not_of('\0'), 0u);
594   EXPECT_EQ(f.find_first_not_of('\0', 3), 4u);
595   EXPECT_EQ(f.find_first_not_of('\0', 2), 2u);
596   // empty string nonsense
597   EXPECT_EQ(d.find_first_not_of('x'), absl::string_view::npos);
598   EXPECT_EQ(e.find_first_not_of('x'), absl::string_view::npos);
599   EXPECT_EQ(d.find_first_not_of('\0'), absl::string_view::npos);
600   EXPECT_EQ(e.find_first_not_of('\0'), absl::string_view::npos);
601 }
602 
603 // Continued from STL2
TEST(StringViewTest,STL2FindLast)604 TEST(StringViewTest, STL2FindLast) {
605   const absl::string_view a("abcdefghijklmnopqrstuvwxyz");
606   const absl::string_view b("abc");
607   const absl::string_view c("xyz");
608   absl::string_view d("foobar");
609   const absl::string_view e;
610   const absl::string_view f(
611       "123"
612       "\0"
613       "456",
614       7);
615   absl::string_view g("xx not found bb");
616   absl::string_view h("====");
617   absl::string_view i("56");
618 
619   d = absl::string_view();
620   EXPECT_EQ(h.find_last_of(a), absl::string_view::npos);
621   EXPECT_EQ(g.find_last_of(a), g.size() - 1);
622   EXPECT_EQ(a.find_last_of(b), 2u);
623   EXPECT_EQ(a.find_last_of(c), a.size() - 1);
624   EXPECT_EQ(f.find_last_of(i), 6u);
625   EXPECT_EQ(a.find_last_of('a'), 0u);
626   EXPECT_EQ(a.find_last_of('b'), 1u);
627   EXPECT_EQ(a.find_last_of('z'), 25u);
628   EXPECT_EQ(a.find_last_of('a', 5), 0u);
629   EXPECT_EQ(a.find_last_of('b', 5), 1u);
630   EXPECT_EQ(a.find_last_of('b', 0), absl::string_view::npos);
631   EXPECT_EQ(a.find_last_of('z', 25), 25u);
632   EXPECT_EQ(a.find_last_of('z', 24), absl::string_view::npos);
633   EXPECT_EQ(f.find_last_of(i, 5), 5u);
634   EXPECT_EQ(f.find_last_of(i, 6), 6u);
635   EXPECT_EQ(f.find_last_of(a, 4), absl::string_view::npos);
636   // empty string nonsense
637   EXPECT_EQ(f.find_last_of(d), absl::string_view::npos);
638   EXPECT_EQ(f.find_last_of(e), absl::string_view::npos);
639   EXPECT_EQ(f.find_last_of(d, 4), absl::string_view::npos);
640   EXPECT_EQ(f.find_last_of(e, 4), absl::string_view::npos);
641   EXPECT_EQ(d.find_last_of(d), absl::string_view::npos);
642   EXPECT_EQ(d.find_last_of(e), absl::string_view::npos);
643   EXPECT_EQ(e.find_last_of(d), absl::string_view::npos);
644   EXPECT_EQ(e.find_last_of(e), absl::string_view::npos);
645   EXPECT_EQ(d.find_last_of(f), absl::string_view::npos);
646   EXPECT_EQ(e.find_last_of(f), absl::string_view::npos);
647   EXPECT_EQ(d.find_last_of(d, 4), absl::string_view::npos);
648   EXPECT_EQ(d.find_last_of(e, 4), absl::string_view::npos);
649   EXPECT_EQ(e.find_last_of(d, 4), absl::string_view::npos);
650   EXPECT_EQ(e.find_last_of(e, 4), absl::string_view::npos);
651   EXPECT_EQ(d.find_last_of(f, 4), absl::string_view::npos);
652   EXPECT_EQ(e.find_last_of(f, 4), absl::string_view::npos);
653 
654   EXPECT_EQ(a.find_last_not_of(b), a.size() - 1);
655   EXPECT_EQ(a.find_last_not_of(c), 22u);
656   EXPECT_EQ(b.find_last_not_of(a), absl::string_view::npos);
657   EXPECT_EQ(b.find_last_not_of(b), absl::string_view::npos);
658   EXPECT_EQ(f.find_last_not_of(i), 4u);
659   EXPECT_EQ(a.find_last_not_of(c, 24), 22u);
660   EXPECT_EQ(a.find_last_not_of(b, 3), 3u);
661   EXPECT_EQ(a.find_last_not_of(b, 2), absl::string_view::npos);
662   // empty string nonsense
663   EXPECT_EQ(f.find_last_not_of(d), f.size() - 1);
664   EXPECT_EQ(f.find_last_not_of(e), f.size() - 1);
665   EXPECT_EQ(f.find_last_not_of(d, 4), 4u);
666   EXPECT_EQ(f.find_last_not_of(e, 4), 4u);
667   EXPECT_EQ(d.find_last_not_of(d), absl::string_view::npos);
668   EXPECT_EQ(d.find_last_not_of(e), absl::string_view::npos);
669   EXPECT_EQ(e.find_last_not_of(d), absl::string_view::npos);
670   EXPECT_EQ(e.find_last_not_of(e), absl::string_view::npos);
671   EXPECT_EQ(d.find_last_not_of(f), absl::string_view::npos);
672   EXPECT_EQ(e.find_last_not_of(f), absl::string_view::npos);
673   EXPECT_EQ(d.find_last_not_of(d, 4), absl::string_view::npos);
674   EXPECT_EQ(d.find_last_not_of(e, 4), absl::string_view::npos);
675   EXPECT_EQ(e.find_last_not_of(d, 4), absl::string_view::npos);
676   EXPECT_EQ(e.find_last_not_of(e, 4), absl::string_view::npos);
677   EXPECT_EQ(d.find_last_not_of(f, 4), absl::string_view::npos);
678   EXPECT_EQ(e.find_last_not_of(f, 4), absl::string_view::npos);
679 
680   EXPECT_EQ(h.find_last_not_of('x'), h.size() - 1);
681   EXPECT_EQ(h.find_last_not_of('='), absl::string_view::npos);
682   EXPECT_EQ(b.find_last_not_of('c'), 1u);
683   EXPECT_EQ(h.find_last_not_of('x', 2), 2u);
684   EXPECT_EQ(h.find_last_not_of('=', 2), absl::string_view::npos);
685   EXPECT_EQ(b.find_last_not_of('b', 1), 0u);
686   // empty string nonsense
687   EXPECT_EQ(d.find_last_not_of('x'), absl::string_view::npos);
688   EXPECT_EQ(e.find_last_not_of('x'), absl::string_view::npos);
689   EXPECT_EQ(d.find_last_not_of('\0'), absl::string_view::npos);
690   EXPECT_EQ(e.find_last_not_of('\0'), absl::string_view::npos);
691 }
692 
693 // Continued from STL2
TEST(StringViewTest,STL2Substr)694 TEST(StringViewTest, STL2Substr) {
695   const absl::string_view a("abcdefghijklmnopqrstuvwxyz");
696   const absl::string_view b("abc");
697   const absl::string_view c("xyz");
698   absl::string_view d("foobar");
699   const absl::string_view e;
700 
701   d = absl::string_view();
702   EXPECT_EQ(a.substr(0, 3), b);
703   EXPECT_EQ(a.substr(23), c);
704   EXPECT_EQ(a.substr(23, 3), c);
705   EXPECT_EQ(a.substr(23, 99), c);
706   EXPECT_EQ(a.substr(0), a);
707   EXPECT_EQ(a.substr(), a);
708   EXPECT_EQ(a.substr(3, 2), "de");
709   // empty string nonsense
710   EXPECT_EQ(d.substr(0, 99), e);
711   // use of npos
712   EXPECT_EQ(a.substr(0, absl::string_view::npos), a);
713   EXPECT_EQ(a.substr(23, absl::string_view::npos), c);
714   // throw exception
715 #ifdef ABSL_HAVE_EXCEPTIONS
716   EXPECT_THROW((void)a.substr(99, 2), std::out_of_range);
717 #else
718   ABSL_EXPECT_DEATH_IF_SUPPORTED((void)a.substr(99, 2),
719                                  "absl::string_view::substr");
720 #endif
721 }
722 
TEST(StringViewTest,TruncSubstr)723 TEST(StringViewTest, TruncSubstr) {
724   const absl::string_view hi("hi");
725   EXPECT_EQ("", absl::ClippedSubstr(hi, 0, 0));
726   EXPECT_EQ("h", absl::ClippedSubstr(hi, 0, 1));
727   EXPECT_EQ("hi", absl::ClippedSubstr(hi, 0));
728   EXPECT_EQ("i", absl::ClippedSubstr(hi, 1));
729   EXPECT_EQ("", absl::ClippedSubstr(hi, 2));
730   EXPECT_EQ("", absl::ClippedSubstr(hi, 3));  // truncation
731   EXPECT_EQ("", absl::ClippedSubstr(hi, 3, 2));  // truncation
732 }
733 
TEST(StringViewTest,UTF8)734 TEST(StringViewTest, UTF8) {
735   std::string utf8 = "\u00E1";
736   std::string utf8_twice = utf8 + " " + utf8;
737   size_t utf8_len = strlen(utf8.data());
738   EXPECT_EQ(utf8_len, absl::string_view(utf8_twice).find_first_of(" "));
739   EXPECT_EQ(utf8_len, absl::string_view(utf8_twice).find_first_of(" \t"));
740 }
741 
TEST(StringViewTest,FindConformance)742 TEST(StringViewTest, FindConformance) {
743   struct {
744     std::string haystack;
745     std::string needle;
746   } specs[] = {
747     {"", ""},
748     {"", "a"},
749     {"a", ""},
750     {"a", "a"},
751     {"a", "b"},
752     {"aa", ""},
753     {"aa", "a"},
754     {"aa", "b"},
755     {"ab", "a"},
756     {"ab", "b"},
757     {"abcd", ""},
758     {"abcd", "a"},
759     {"abcd", "d"},
760     {"abcd", "ab"},
761     {"abcd", "bc"},
762     {"abcd", "cd"},
763     {"abcd", "abcd"},
764   };
765   for (const auto& s : specs) {
766     SCOPED_TRACE(s.haystack);
767     SCOPED_TRACE(s.needle);
768     std::string st = s.haystack;
769     absl::string_view sp = s.haystack;
770     for (size_t i = 0; i <= sp.size(); ++i) {
771       size_t pos = (i == sp.size()) ? absl::string_view::npos : i;
772       SCOPED_TRACE(pos);
773       EXPECT_EQ(sp.find(s.needle, pos),
774                 st.find(s.needle, pos));
775       EXPECT_EQ(sp.rfind(s.needle, pos),
776                 st.rfind(s.needle, pos));
777       EXPECT_EQ(sp.find_first_of(s.needle, pos),
778                 st.find_first_of(s.needle, pos));
779       EXPECT_EQ(sp.find_first_not_of(s.needle, pos),
780                 st.find_first_not_of(s.needle, pos));
781       EXPECT_EQ(sp.find_last_of(s.needle, pos),
782                 st.find_last_of(s.needle, pos));
783       EXPECT_EQ(sp.find_last_not_of(s.needle, pos),
784                 st.find_last_not_of(s.needle, pos));
785     }
786   }
787 }
788 
TEST(StringViewTest,Remove)789 TEST(StringViewTest, Remove) {
790   absl::string_view a("foobar");
791   std::string s1("123");
792   s1 += '\0';
793   s1 += "456";
794   absl::string_view e;
795   std::string s2;
796 
797   // remove_prefix
798   absl::string_view c(a);
799   c.remove_prefix(3);
800   EXPECT_EQ(c, "bar");
801   c = a;
802   c.remove_prefix(0);
803   EXPECT_EQ(c, a);
804   c.remove_prefix(c.size());
805   EXPECT_EQ(c, e);
806 
807   // remove_suffix
808   c = a;
809   c.remove_suffix(3);
810   EXPECT_EQ(c, "foo");
811   c = a;
812   c.remove_suffix(0);
813   EXPECT_EQ(c, a);
814   c.remove_suffix(c.size());
815   EXPECT_EQ(c, e);
816 }
817 
TEST(StringViewTest,Set)818 TEST(StringViewTest, Set) {
819   absl::string_view a("foobar");
820   absl::string_view empty;
821   absl::string_view b;
822 
823   // set
824   b = absl::string_view("foobar", 6);
825   EXPECT_EQ(b, a);
826   b = absl::string_view("foobar", 0);
827   EXPECT_EQ(b, empty);
828   b = absl::string_view("foobar", 7);
829   EXPECT_NE(b, a);
830 
831   b = absl::string_view("foobar");
832   EXPECT_EQ(b, a);
833 }
834 
TEST(StringViewTest,FrontBack)835 TEST(StringViewTest, FrontBack) {
836   static const char arr[] = "abcd";
837   const absl::string_view csp(arr, 4);
838   EXPECT_EQ(&arr[0], &csp.front());
839   EXPECT_EQ(&arr[3], &csp.back());
840 }
841 
TEST(StringViewTest,FrontBackSingleChar)842 TEST(StringViewTest, FrontBackSingleChar) {
843   static const char c = 'a';
844   const absl::string_view csp(&c, 1);
845   EXPECT_EQ(&c, &csp.front());
846   EXPECT_EQ(&c, &csp.back());
847 }
848 
TEST(StringViewTest,FrontBackEmpty)849 TEST(StringViewTest, FrontBackEmpty) {
850 #ifndef ABSL_USES_STD_STRING_VIEW
851 #if !defined(NDEBUG) || ABSL_OPTION_HARDENED
852   // Abseil's string_view implementation has debug assertions that check that
853   // front() and back() are not called on an empty string_view.
854   absl::string_view sv;
855   ABSL_EXPECT_DEATH_IF_SUPPORTED(sv.front(), "");
856   ABSL_EXPECT_DEATH_IF_SUPPORTED(sv.back(), "");
857 #endif
858 #endif
859 }
860 
861 // `std::string_view::string_view(const char*)` calls
862 // `std::char_traits<char>::length(const char*)` to get the string length. In
863 // libc++, it doesn't allow `nullptr` in the constexpr context, with the error
864 // "read of dereferenced null pointer is not allowed in a constant expression".
865 // At run time, the behavior of `std::char_traits::length()` on `nullptr` is
866 // undefined by the standard and usually results in crash with libc++.
867 // GCC also started rejected this in libstdc++ starting in GCC9.
868 // In MSVC, creating a constexpr string_view from nullptr also triggers an
869 // "unevaluable pointer value" error. This compiler implementation conforms
870 // to the standard, but `absl::string_view` implements a different
871 // behavior for historical reasons. We work around tests that construct
872 // `string_view` from `nullptr` when using libc++.
873 #if !defined(ABSL_USES_STD_STRING_VIEW) ||                    \
874     (!(defined(_GLIBCXX_RELEASE) && _GLIBCXX_RELEASE >= 9) && \
875      !defined(_LIBCPP_VERSION) && !defined(_MSC_VER))
876 #define ABSL_HAVE_STRING_VIEW_FROM_NULLPTR 1
877 #endif
878 
TEST(StringViewTest,NULLInput)879 TEST(StringViewTest, NULLInput) {
880   absl::string_view s;
881   EXPECT_EQ(s.data(), nullptr);
882   EXPECT_EQ(s.size(), 0u);
883 
884 #ifdef ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
885   s = absl::string_view(nullptr);
886   EXPECT_EQ(s.data(), nullptr);
887   EXPECT_EQ(s.size(), 0u);
888 
889   // .ToString() on a absl::string_view with nullptr should produce the empty
890   // string.
891   EXPECT_EQ("", std::string(s));
892 #endif  // ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
893 }
894 
TEST(StringViewTest,Comparisons2)895 TEST(StringViewTest, Comparisons2) {
896   // The `compare` member has 6 overloads (v: string_view, s: const char*):
897   //  (1) compare(v)
898   //  (2) compare(pos1, count1, v)
899   //  (3) compare(pos1, count1, v, pos2, count2)
900   //  (4) compare(s)
901   //  (5) compare(pos1, count1, s)
902   //  (6) compare(pos1, count1, s, count2)
903 
904   absl::string_view abc("abcdefghijklmnopqrstuvwxyz");
905 
906   // check comparison operations on strings longer than 4 bytes.
907   EXPECT_EQ(abc, absl::string_view("abcdefghijklmnopqrstuvwxyz"));
908   EXPECT_EQ(abc.compare(absl::string_view("abcdefghijklmnopqrstuvwxyz")), 0);
909 
910   EXPECT_LT(abc, absl::string_view("abcdefghijklmnopqrstuvwxzz"));
911   EXPECT_LT(abc.compare(absl::string_view("abcdefghijklmnopqrstuvwxzz")), 0);
912 
913   EXPECT_GT(abc, absl::string_view("abcdefghijklmnopqrstuvwxyy"));
914   EXPECT_GT(abc.compare(absl::string_view("abcdefghijklmnopqrstuvwxyy")), 0);
915 
916   // The "substr" variants of `compare`.
917   absl::string_view digits("0123456789");
918   auto npos = absl::string_view::npos;
919 
920   // Taking string_view
921   EXPECT_EQ(digits.compare(3, npos, absl::string_view("3456789")), 0);  // 2
922   EXPECT_EQ(digits.compare(3, 4, absl::string_view("3456")), 0);        // 2
923   EXPECT_EQ(digits.compare(10, 0, absl::string_view()), 0);             // 2
924   EXPECT_EQ(digits.compare(3, 4, absl::string_view("0123456789"), 3, 4),
925             0);  // 3
926   EXPECT_LT(digits.compare(3, 4, absl::string_view("0123456789"), 3, 5),
927             0);  // 3
928   EXPECT_LT(digits.compare(0, npos, absl::string_view("0123456789"), 3, 5),
929             0);  // 3
930   // Taking const char*
931   EXPECT_EQ(digits.compare(3, 4, "3456"), 0);                 // 5
932   EXPECT_EQ(digits.compare(3, npos, "3456789"), 0);           // 5
933   EXPECT_EQ(digits.compare(10, 0, ""), 0);                    // 5
934   EXPECT_EQ(digits.compare(3, 4, "0123456789", 3, 4), 0);     // 6
935   EXPECT_LT(digits.compare(3, 4, "0123456789", 3, 5), 0);     // 6
936   EXPECT_LT(digits.compare(0, npos, "0123456789", 3, 5), 0);  // 6
937 }
938 
TEST(StringViewTest,At)939 TEST(StringViewTest, At) {
940   absl::string_view abc = "abc";
941   EXPECT_EQ(abc.at(0), 'a');
942   EXPECT_EQ(abc.at(1), 'b');
943   EXPECT_EQ(abc.at(2), 'c');
944 #ifdef ABSL_HAVE_EXCEPTIONS
945   EXPECT_THROW((void)abc.at(3), std::out_of_range);
946 #else
947   ABSL_EXPECT_DEATH_IF_SUPPORTED((void)abc.at(3), "absl::string_view::at");
948 #endif
949 }
950 
951 struct MyCharAlloc : std::allocator<char> {};
952 
TEST(StringViewTest,ExplicitConversionOperator)953 TEST(StringViewTest, ExplicitConversionOperator) {
954   absl::string_view sp = "hi";
955   EXPECT_EQ(sp, std::string(sp));
956 }
957 
TEST(StringViewTest,NullSafeStringView)958 TEST(StringViewTest, NullSafeStringView) {
959   {
960     absl::string_view s = absl::NullSafeStringView(nullptr);
961     EXPECT_EQ(nullptr, s.data());
962     EXPECT_EQ(0u, s.size());
963     EXPECT_EQ(absl::string_view(), s);
964   }
965   {
966     static const char kHi[] = "hi";
967     absl::string_view s = absl::NullSafeStringView(kHi);
968     EXPECT_EQ(kHi, s.data());
969     EXPECT_EQ(strlen(kHi), s.size());
970     EXPECT_EQ(absl::string_view("hi"), s);
971   }
972 }
973 
TEST(StringViewTest,ConstexprNullSafeStringView)974 TEST(StringViewTest, ConstexprNullSafeStringView) {
975   {
976     constexpr absl::string_view s = absl::NullSafeStringView(nullptr);
977     EXPECT_EQ(nullptr, s.data());
978     EXPECT_EQ(0u, s.size());
979     EXPECT_EQ(absl::string_view(), s);
980   }
981 #if !defined(_MSC_VER) || _MSC_VER >= 1910
982   // MSVC 2017+ is required for good constexpr string_view support.
983   // See the implementation of `absl::string_view::StrlenInternal()`.
984   {
985     static constexpr char kHi[] = "hi";
986     absl::string_view s = absl::NullSafeStringView(kHi);
987     EXPECT_EQ(kHi, s.data());
988     EXPECT_EQ(strlen(kHi), s.size());
989     EXPECT_EQ(absl::string_view("hi"), s);
990   }
991   {
992     constexpr absl::string_view s = absl::NullSafeStringView("hello");
993     EXPECT_EQ(s.size(), 5u);
994     EXPECT_EQ("hello", s);
995   }
996 #endif
997 }
998 
TEST(StringViewTest,ConstexprCompiles)999 TEST(StringViewTest, ConstexprCompiles) {
1000   constexpr absl::string_view sp;
1001 #ifdef ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
1002   constexpr absl::string_view cstr(nullptr);
1003 #endif
1004   constexpr absl::string_view cstr_len("cstr", 4);
1005 
1006 #if defined(ABSL_USES_STD_STRING_VIEW)
1007   // In libstdc++ (as of 7.2), `std::string_view::string_view(const char*)`
1008   // calls `std::char_traits<char>::length(const char*)` to get the string
1009   // length, but it is not marked constexpr yet. See GCC bug:
1010   // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78156
1011   // Also, there is a LWG issue that adds constexpr to length() which was just
1012   // resolved 2017-06-02. See
1013   // http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-defects.html#2232
1014   // TODO(zhangxy): Update the condition when libstdc++ adopts the constexpr
1015   // length().
1016 #if !defined(__GLIBCXX__)
1017 #define ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR 1
1018 #endif  // !__GLIBCXX__
1019 
1020 #else  // ABSL_USES_STD_STRING_VIEW
1021 
1022 // This duplicates the check for __builtin_strlen in the header.
1023 #if ABSL_HAVE_BUILTIN(__builtin_strlen) || \
1024     (defined(__GNUC__) && !defined(__clang__))
1025 #define ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR 1
1026 #elif defined(__GNUC__)  // GCC or clang
1027 #error GCC/clang should have constexpr string_view.
1028 #endif
1029 
1030 // MSVC 2017+ should be able to construct a constexpr string_view from a cstr.
1031 #if defined(_MSC_VER) && _MSC_VER >= 1910
1032 #define ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR 1
1033 #endif
1034 
1035 #endif  // ABSL_USES_STD_STRING_VIEW
1036 
1037 #ifdef ABSL_HAVE_CONSTEXPR_STRING_VIEW_FROM_CSTR
1038   constexpr absl::string_view cstr_strlen("foo");
1039   EXPECT_EQ(cstr_strlen.length(), 3u);
1040   constexpr absl::string_view cstr_strlen2 = "bar";
1041   EXPECT_EQ(cstr_strlen2, "bar");
1042 
1043 #if ABSL_HAVE_BUILTIN(__builtin_memcmp) || \
1044     (defined(__GNUC__) && !defined(__clang__))
1045 #define ABSL_HAVE_CONSTEXPR_STRING_VIEW_COMPARISON 1
1046 #endif
1047 #ifdef ABSL_HAVE_CONSTEXPR_STRING_VIEW_COMPARISON
1048   constexpr absl::string_view foo = "foo";
1049   constexpr absl::string_view bar = "bar";
1050   constexpr bool foo_eq_bar = foo == bar;
1051   constexpr bool foo_ne_bar = foo != bar;
1052   constexpr bool foo_lt_bar = foo < bar;
1053   constexpr bool foo_le_bar = foo <= bar;
1054   constexpr bool foo_gt_bar = foo > bar;
1055   constexpr bool foo_ge_bar = foo >= bar;
1056   constexpr int foo_compare_bar = foo.compare(bar);
1057   EXPECT_FALSE(foo_eq_bar);
1058   EXPECT_TRUE(foo_ne_bar);
1059   EXPECT_FALSE(foo_lt_bar);
1060   EXPECT_FALSE(foo_le_bar);
1061   EXPECT_TRUE(foo_gt_bar);
1062   EXPECT_TRUE(foo_ge_bar);
1063   EXPECT_GT(foo_compare_bar, 0);
1064 #endif
1065 #endif
1066 
1067 #if !defined(__clang__) || 3 < __clang_major__ || \
1068   (3 == __clang_major__ && 4 < __clang_minor__)
1069   // older clang versions (< 3.5) complain that:
1070   //   "cannot perform pointer arithmetic on null pointer"
1071   constexpr absl::string_view::iterator const_begin_empty = sp.begin();
1072   constexpr absl::string_view::iterator const_end_empty = sp.end();
1073   EXPECT_EQ(const_begin_empty, const_end_empty);
1074 
1075 #ifdef ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
1076   constexpr absl::string_view::iterator const_begin_nullptr = cstr.begin();
1077   constexpr absl::string_view::iterator const_end_nullptr = cstr.end();
1078   EXPECT_EQ(const_begin_nullptr, const_end_nullptr);
1079 #endif  // ABSL_HAVE_STRING_VIEW_FROM_NULLPTR
1080 #endif  // !defined(__clang__) || ...
1081 
1082   constexpr absl::string_view::iterator const_begin = cstr_len.begin();
1083   constexpr absl::string_view::iterator const_end = cstr_len.end();
1084   constexpr absl::string_view::size_type const_size = cstr_len.size();
1085   constexpr absl::string_view::size_type const_length = cstr_len.length();
1086   static_assert(const_begin + const_size == const_end,
1087                 "pointer arithmetic check");
1088   static_assert(const_begin + const_length == const_end,
1089                 "pointer arithmetic check");
1090 #ifndef _MSC_VER
1091   // MSVC has bugs doing constexpr pointer arithmetic.
1092   // https://developercommunity.visualstudio.com/content/problem/482192/bad-pointer-arithmetic-in-constepxr-2019-rc1-svc1.html
1093   EXPECT_EQ(const_begin + const_size, const_end);
1094   EXPECT_EQ(const_begin + const_length, const_end);
1095 #endif
1096 
1097   constexpr bool isempty = sp.empty();
1098   EXPECT_TRUE(isempty);
1099 
1100   constexpr const char c = cstr_len[2];
1101   EXPECT_EQ(c, 't');
1102 
1103   constexpr const char cfront = cstr_len.front();
1104   constexpr const char cback = cstr_len.back();
1105   EXPECT_EQ(cfront, 'c');
1106   EXPECT_EQ(cback, 'r');
1107 
1108   constexpr const char* np = sp.data();
1109   constexpr const char* cstr_ptr = cstr_len.data();
1110   EXPECT_EQ(np, nullptr);
1111   EXPECT_NE(cstr_ptr, nullptr);
1112 
1113   constexpr size_t sp_npos = sp.npos;
1114   EXPECT_EQ(sp_npos, static_cast<size_t>(-1));
1115 }
1116 
ConstexprMethodsHelper()1117 constexpr char ConstexprMethodsHelper() {
1118 #if defined(__cplusplus) && __cplusplus >= 201402L
1119   absl::string_view str("123", 3);
1120   str.remove_prefix(1);
1121   str.remove_suffix(1);
1122   absl::string_view bar;
1123   str.swap(bar);
1124   return bar.front();
1125 #else
1126   return '2';
1127 #endif
1128 }
1129 
TEST(StringViewTest,ConstexprMethods)1130 TEST(StringViewTest, ConstexprMethods) {
1131   // remove_prefix, remove_suffix, swap
1132   static_assert(ConstexprMethodsHelper() == '2', "");
1133 
1134   // substr
1135   constexpr absl::string_view foobar("foobar", 6);
1136   constexpr absl::string_view foo = foobar.substr(0, 3);
1137   constexpr absl::string_view bar = foobar.substr(3);
1138   EXPECT_EQ(foo, "foo");
1139   EXPECT_EQ(bar, "bar");
1140 }
1141 
TEST(StringViewTest,Noexcept)1142 TEST(StringViewTest, Noexcept) {
1143   EXPECT_TRUE((std::is_nothrow_constructible<absl::string_view,
1144                                              const std::string&>::value));
1145   EXPECT_TRUE((std::is_nothrow_constructible<absl::string_view,
1146                                              const std::string&>::value));
1147   EXPECT_TRUE(std::is_nothrow_constructible<absl::string_view>::value);
1148   constexpr absl::string_view sp;
1149   EXPECT_TRUE(noexcept(sp.begin()));
1150   EXPECT_TRUE(noexcept(sp.end()));
1151   EXPECT_TRUE(noexcept(sp.cbegin()));
1152   EXPECT_TRUE(noexcept(sp.cend()));
1153   EXPECT_TRUE(noexcept(sp.rbegin()));
1154   EXPECT_TRUE(noexcept(sp.rend()));
1155   EXPECT_TRUE(noexcept(sp.crbegin()));
1156   EXPECT_TRUE(noexcept(sp.crend()));
1157   EXPECT_TRUE(noexcept(sp.size()));
1158   EXPECT_TRUE(noexcept(sp.length()));
1159   EXPECT_TRUE(noexcept(sp.empty()));
1160   EXPECT_TRUE(noexcept(sp.data()));
1161   EXPECT_TRUE(noexcept(sp.compare(sp)));
1162   EXPECT_TRUE(noexcept(sp.find(sp)));
1163   EXPECT_TRUE(noexcept(sp.find('f')));
1164   EXPECT_TRUE(noexcept(sp.rfind(sp)));
1165   EXPECT_TRUE(noexcept(sp.rfind('f')));
1166   EXPECT_TRUE(noexcept(sp.find_first_of(sp)));
1167   EXPECT_TRUE(noexcept(sp.find_first_of('f')));
1168   EXPECT_TRUE(noexcept(sp.find_last_of(sp)));
1169   EXPECT_TRUE(noexcept(sp.find_last_of('f')));
1170   EXPECT_TRUE(noexcept(sp.find_first_not_of(sp)));
1171   EXPECT_TRUE(noexcept(sp.find_first_not_of('f')));
1172   EXPECT_TRUE(noexcept(sp.find_last_not_of(sp)));
1173   EXPECT_TRUE(noexcept(sp.find_last_not_of('f')));
1174 }
1175 
TEST(StringViewTest,BoundsCheck)1176 TEST(StringViewTest, BoundsCheck) {
1177 #ifndef ABSL_USES_STD_STRING_VIEW
1178 #if !defined(NDEBUG) || ABSL_OPTION_HARDENED
1179   // Abseil's string_view implementation has bounds-checking in debug mode.
1180   absl::string_view h = "hello";
1181   ABSL_EXPECT_DEATH_IF_SUPPORTED(h[5], "");
1182   ABSL_EXPECT_DEATH_IF_SUPPORTED(h[static_cast<size_t>(-1)], "");
1183 #endif
1184 #endif
1185 }
1186 
TEST(ComparisonOpsTest,StringCompareNotAmbiguous)1187 TEST(ComparisonOpsTest, StringCompareNotAmbiguous) {
1188   EXPECT_EQ("hello", std::string("hello"));
1189   EXPECT_LT("hello", std::string("world"));
1190 }
1191 
TEST(ComparisonOpsTest,HeterogeneousStringViewEquals)1192 TEST(ComparisonOpsTest, HeterogeneousStringViewEquals) {
1193   EXPECT_EQ(absl::string_view("hello"), std::string("hello"));
1194   EXPECT_EQ("hello", absl::string_view("hello"));
1195 }
1196 
TEST(FindOneCharTest,EdgeCases)1197 TEST(FindOneCharTest, EdgeCases) {
1198   absl::string_view a("xxyyyxx");
1199 
1200   // Set a = "xyyyx".
1201   a.remove_prefix(1);
1202   a.remove_suffix(1);
1203 
1204   EXPECT_EQ(0u, a.find('x'));
1205   EXPECT_EQ(0u, a.find('x', 0));
1206   EXPECT_EQ(4u, a.find('x', 1));
1207   EXPECT_EQ(4u, a.find('x', 4));
1208   EXPECT_EQ(absl::string_view::npos, a.find('x', 5));
1209 
1210   EXPECT_EQ(4u, a.rfind('x'));
1211   EXPECT_EQ(4u, a.rfind('x', 5));
1212   EXPECT_EQ(4u, a.rfind('x', 4));
1213   EXPECT_EQ(0u, a.rfind('x', 3));
1214   EXPECT_EQ(0u, a.rfind('x', 0));
1215 
1216   // Set a = "yyy".
1217   a.remove_prefix(1);
1218   a.remove_suffix(1);
1219 
1220   EXPECT_EQ(absl::string_view::npos, a.find('x'));
1221   EXPECT_EQ(absl::string_view::npos, a.rfind('x'));
1222 }
1223 
1224 #ifndef ABSL_HAVE_THREAD_SANITIZER  // Allocates too much memory for tsan.
TEST(HugeStringView,TwoPointTwoGB)1225 TEST(HugeStringView, TwoPointTwoGB) {
1226   if (sizeof(size_t) <= 4)
1227     return;
1228   // Try a huge string piece.
1229   const size_t size = size_t{2200} * 1000 * 1000;
1230   std::string s(size, 'a');
1231   absl::string_view sp(s);
1232   EXPECT_EQ(size, sp.length());
1233   sp.remove_prefix(1);
1234   EXPECT_EQ(size - 1, sp.length());
1235   sp.remove_suffix(2);
1236   EXPECT_EQ(size - 1 - 2, sp.length());
1237 }
1238 #endif  // ABSL_HAVE_THREAD_SANITIZER
1239 
1240 #if !defined(NDEBUG) && !defined(ABSL_USES_STD_STRING_VIEW)
TEST(NonNegativeLenTest,NonNegativeLen)1241 TEST(NonNegativeLenTest, NonNegativeLen) {
1242   ABSL_EXPECT_DEATH_IF_SUPPORTED(
1243       absl::string_view("xyz", static_cast<size_t>(-1)), "len <= kMaxSize");
1244 }
1245 
TEST(LenExceedsMaxSizeTest,LenExceedsMaxSize)1246 TEST(LenExceedsMaxSizeTest, LenExceedsMaxSize) {
1247   auto max_size = absl::string_view().max_size();
1248 
1249   // This should construct ok (although the view itself is obviously invalid).
1250   absl::string_view ok_view("", max_size);
1251 
1252   // Adding one to the max should trigger an assertion.
1253   ABSL_EXPECT_DEATH_IF_SUPPORTED(absl::string_view("", max_size + 1),
1254                                  "len <= kMaxSize");
1255 }
1256 #endif  // !defined(NDEBUG) && !defined(ABSL_USES_STD_STRING_VIEW)
1257 
1258 class StringViewStreamTest : public ::testing::Test {
1259  public:
1260   // Set negative 'width' for right justification.
1261   template <typename T>
Pad(const T & s,int width,char fill=0)1262   std::string Pad(const T& s, int width, char fill = 0) {
1263     std::ostringstream oss;
1264     if (fill != 0) {
1265       oss << std::setfill(fill);
1266     }
1267     if (width < 0) {
1268       width = -width;
1269       oss << std::right;
1270     }
1271     oss << std::setw(width) << s;
1272     return oss.str();
1273   }
1274 };
1275 
TEST_F(StringViewStreamTest,Padding)1276 TEST_F(StringViewStreamTest, Padding) {
1277   std::string s("hello");
1278   absl::string_view sp(s);
1279   for (int w = -64; w < 64; ++w) {
1280     SCOPED_TRACE(w);
1281     EXPECT_EQ(Pad(s, w), Pad(sp, w));
1282   }
1283   for (int w = -64; w < 64; ++w) {
1284     SCOPED_TRACE(w);
1285     EXPECT_EQ(Pad(s, w, '#'), Pad(sp, w, '#'));
1286   }
1287 }
1288 
TEST_F(StringViewStreamTest,ResetsWidth)1289 TEST_F(StringViewStreamTest, ResetsWidth) {
1290   // Width should reset after one formatted write.
1291   // If we weren't resetting width after formatting the string_view,
1292   // we'd have width=5 carrying over to the printing of the "]",
1293   // creating "[###hi####]".
1294   std::string s = "hi";
1295   absl::string_view sp = s;
1296   {
1297     std::ostringstream oss;
1298     oss << "[" << std::setfill('#') << std::setw(5) << s << "]";
1299     ASSERT_EQ("[###hi]", oss.str());
1300   }
1301   {
1302     std::ostringstream oss;
1303     oss << "[" << std::setfill('#') << std::setw(5) << sp << "]";
1304     EXPECT_EQ("[###hi]", oss.str());
1305   }
1306 }
1307 
1308 }  // namespace
1309