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str_split_test.cc (35319B)


      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/str_split.h"
     16 
     17 #include <array>
     18 #include <cstddef>
     19 #include <cstdint>
     20 #include <deque>
     21 #include <initializer_list>
     22 #include <list>
     23 #include <map>
     24 #include <memory>
     25 #include <set>
     26 #include <string>
     27 #include <unordered_map>
     28 #include <unordered_set>
     29 #include <utility>
     30 #include <vector>
     31 
     32 #include "gmock/gmock.h"
     33 #include "gtest/gtest.h"
     34 #include "absl/base/macros.h"
     35 #include "absl/container/btree_map.h"
     36 #include "absl/container/btree_set.h"
     37 #include "absl/container/flat_hash_map.h"
     38 #include "absl/container/node_hash_map.h"
     39 #include "absl/strings/string_view.h"
     40 
     41 namespace {
     42 
     43 using ::testing::ElementsAre;
     44 using ::testing::IsEmpty;
     45 using ::testing::Pair;
     46 using ::testing::UnorderedElementsAre;
     47 
     48 TEST(Split, TraitsTest) {
     49  static_assert(!absl::strings_internal::SplitterIsConvertibleTo<int>::value,
     50                "");
     51  static_assert(
     52      !absl::strings_internal::SplitterIsConvertibleTo<std::string>::value, "");
     53  static_assert(absl::strings_internal::SplitterIsConvertibleTo<
     54                    std::vector<std::string>>::value,
     55                "");
     56  static_assert(
     57      !absl::strings_internal::SplitterIsConvertibleTo<std::vector<int>>::value,
     58      "");
     59  static_assert(absl::strings_internal::SplitterIsConvertibleTo<
     60                    std::vector<absl::string_view>>::value,
     61                "");
     62  static_assert(absl::strings_internal::SplitterIsConvertibleTo<
     63                    std::map<std::string, std::string>>::value,
     64                "");
     65  static_assert(absl::strings_internal::SplitterIsConvertibleTo<
     66                    std::map<absl::string_view, absl::string_view>>::value,
     67                "");
     68  static_assert(!absl::strings_internal::SplitterIsConvertibleTo<
     69                    std::map<int, std::string>>::value,
     70                "");
     71  static_assert(!absl::strings_internal::SplitterIsConvertibleTo<
     72                    std::map<std::string, int>>::value,
     73                "");
     74 }
     75 
     76 // This tests the overall split API, which is made up of the absl::StrSplit()
     77 // function and the Delimiter objects in the absl:: namespace.
     78 // This TEST macro is outside of any namespace to require full specification of
     79 // namespaces just like callers will need to use.
     80 TEST(Split, APIExamples) {
     81  {
     82    // Passes string delimiter. Assumes the default of ByString.
     83    std::vector<std::string> v = absl::StrSplit("a,b,c", ",");  // NOLINT
     84    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
     85 
     86    // Equivalent to...
     87    using absl::ByString;
     88    v = absl::StrSplit("a,b,c", ByString(","));
     89    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
     90 
     91    // Equivalent to...
     92    EXPECT_THAT(absl::StrSplit("a,b,c", ByString(",")),
     93                ElementsAre("a", "b", "c"));
     94  }
     95 
     96  {
     97    // Same as above, but using a single character as the delimiter.
     98    std::vector<std::string> v = absl::StrSplit("a,b,c", ',');
     99    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    100 
    101    // Equivalent to...
    102    using absl::ByChar;
    103    v = absl::StrSplit("a,b,c", ByChar(','));
    104    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    105  }
    106 
    107  {
    108    // Uses the Literal string "=>" as the delimiter.
    109    const std::vector<std::string> v = absl::StrSplit("a=>b=>c", "=>");
    110    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    111  }
    112 
    113  {
    114    // The substrings are returned as string_views, eliminating copying.
    115    std::vector<absl::string_view> v = absl::StrSplit("a,b,c", ',');
    116    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    117  }
    118 
    119  {
    120    // Leading and trailing empty substrings.
    121    std::vector<std::string> v = absl::StrSplit(",a,b,c,", ',');
    122    EXPECT_THAT(v, ElementsAre("", "a", "b", "c", ""));
    123  }
    124 
    125  {
    126    // Splits on a delimiter that is not found.
    127    std::vector<std::string> v = absl::StrSplit("abc", ',');
    128    EXPECT_THAT(v, ElementsAre("abc"));
    129  }
    130 
    131  {
    132    // Splits the input string into individual characters by using an empty
    133    // string as the delimiter.
    134    std::vector<std::string> v = absl::StrSplit("abc", "");
    135    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    136  }
    137 
    138  {
    139    // Splits string data with embedded NUL characters, using NUL as the
    140    // delimiter. A simple delimiter of "\0" doesn't work because strlen() will
    141    // say that's the empty string when constructing the absl::string_view
    142    // delimiter. Instead, a non-empty string containing NUL can be used as the
    143    // delimiter.
    144    std::string embedded_nulls("a\0b\0c", 5);
    145    std::string null_delim("\0", 1);
    146    std::vector<std::string> v = absl::StrSplit(embedded_nulls, null_delim);
    147    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    148  }
    149 
    150  {
    151    // Stores first two split strings as the members in a std::pair.
    152    std::pair<std::string, std::string> p = absl::StrSplit("a,b,c", ',');
    153    EXPECT_EQ("a", p.first);
    154    EXPECT_EQ("b", p.second);
    155    // "c" is omitted because std::pair can hold only two elements.
    156  }
    157 
    158  {
    159    // Results stored in std::set<std::string>
    160    std::set<std::string> v = absl::StrSplit("a,b,c,a,b,c,a,b,c", ',');
    161    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    162  }
    163 
    164  {
    165    // Uses a non-const char* delimiter.
    166    char a[] = ",";
    167    char* d = a + 0;
    168    std::vector<std::string> v = absl::StrSplit("a,b,c", d);
    169    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    170  }
    171 
    172  {
    173    // Results split using either of , or ;
    174    using absl::ByAnyChar;
    175    std::vector<std::string> v = absl::StrSplit("a,b;c", ByAnyChar(",;"));
    176    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    177  }
    178 
    179  {
    180    // Uses the SkipWhitespace predicate.
    181    using absl::SkipWhitespace;
    182    std::vector<std::string> v =
    183        absl::StrSplit(" a , ,,b,", ',', SkipWhitespace());
    184    EXPECT_THAT(v, ElementsAre(" a ", "b"));
    185  }
    186 
    187  {
    188    // Uses the ByLength delimiter.
    189    using absl::ByLength;
    190    std::vector<std::string> v = absl::StrSplit("abcdefg", ByLength(3));
    191    EXPECT_THAT(v, ElementsAre("abc", "def", "g"));
    192  }
    193 
    194  {
    195    // Different forms of initialization / conversion.
    196    std::vector<std::string> v1 = absl::StrSplit("a,b,c", ',');
    197    EXPECT_THAT(v1, ElementsAre("a", "b", "c"));
    198    std::vector<std::string> v2(absl::StrSplit("a,b,c", ','));
    199    EXPECT_THAT(v2, ElementsAre("a", "b", "c"));
    200    auto v3 = std::vector<std::string>(absl::StrSplit("a,b,c", ','));
    201    EXPECT_THAT(v3, ElementsAre("a", "b", "c"));
    202    v3 = absl::StrSplit("a,b,c", ',');
    203    EXPECT_THAT(v3, ElementsAre("a", "b", "c"));
    204  }
    205 
    206  {
    207    // Results stored in a std::map.
    208    std::map<std::string, std::string> m = absl::StrSplit("a,1,b,2,a,3", ',');
    209    EXPECT_EQ(2, m.size());
    210    EXPECT_EQ("3", m["a"]);
    211    EXPECT_EQ("2", m["b"]);
    212  }
    213 
    214  {
    215    // Results stored in a std::multimap.
    216    std::multimap<std::string, std::string> m =
    217        absl::StrSplit("a,1,b,2,a,3", ',');
    218    EXPECT_EQ(3, m.size());
    219    auto it = m.find("a");
    220    EXPECT_EQ("1", it->second);
    221    ++it;
    222    EXPECT_EQ("3", it->second);
    223    it = m.find("b");
    224    EXPECT_EQ("2", it->second);
    225  }
    226 
    227  {
    228    // Demonstrates use in a range-based for loop in C++11.
    229    std::string s = "x,x,x,x,x,x,x";
    230    for (absl::string_view sp : absl::StrSplit(s, ',')) {
    231      EXPECT_EQ("x", sp);
    232    }
    233  }
    234 
    235  {
    236    // Demonstrates use with a Predicate in a range-based for loop.
    237    using absl::SkipWhitespace;
    238    std::string s = " ,x,,x,,x,x,x,,";
    239    for (absl::string_view sp : absl::StrSplit(s, ',', SkipWhitespace())) {
    240      EXPECT_EQ("x", sp);
    241    }
    242  }
    243 
    244  {
    245    // Demonstrates a "smart" split to std::map using two separate calls to
    246    // absl::StrSplit. One call to split the records, and another call to split
    247    // the keys and values. This also uses the Limit delimiter so that the
    248    // std::string "a=b=c" will split to "a" -> "b=c".
    249    std::map<std::string, std::string> m;
    250    for (absl::string_view sp : absl::StrSplit("a=b=c,d=e,f=,g", ',')) {
    251      m.insert(absl::StrSplit(sp, absl::MaxSplits('=', 1)));
    252    }
    253    EXPECT_EQ("b=c", m.find("a")->second);
    254    EXPECT_EQ("e", m.find("d")->second);
    255    EXPECT_EQ("", m.find("f")->second);
    256    EXPECT_EQ("", m.find("g")->second);
    257  }
    258 }
    259 
    260 //
    261 // Tests for SplitIterator
    262 //
    263 
    264 TEST(SplitIterator, Basics) {
    265  auto splitter = absl::StrSplit("a,b", ',');
    266  auto it = splitter.begin();
    267  auto end = splitter.end();
    268 
    269  EXPECT_NE(it, end);
    270  EXPECT_EQ("a", *it);  // tests dereference
    271  ++it;                 // tests preincrement
    272  EXPECT_NE(it, end);
    273  EXPECT_EQ("b",
    274            std::string(it->data(), it->size()));  // tests dereference as ptr
    275  it++;                                            // tests postincrement
    276  EXPECT_EQ(it, end);
    277 }
    278 
    279 // Simple Predicate to skip a particular string.
    280 class Skip {
    281 public:
    282  explicit Skip(const std::string& s) : s_(s) {}
    283  bool operator()(absl::string_view sp) { return sp != s_; }
    284 
    285 private:
    286  std::string s_;
    287 };
    288 
    289 TEST(SplitIterator, Predicate) {
    290  auto splitter = absl::StrSplit("a,b,c", ',', Skip("b"));
    291  auto it = splitter.begin();
    292  auto end = splitter.end();
    293 
    294  EXPECT_NE(it, end);
    295  EXPECT_EQ("a", *it);  // tests dereference
    296  ++it;                 // tests preincrement -- "b" should be skipped here.
    297  EXPECT_NE(it, end);
    298  EXPECT_EQ("c",
    299            std::string(it->data(), it->size()));  // tests dereference as ptr
    300  it++;                                            // tests postincrement
    301  EXPECT_EQ(it, end);
    302 }
    303 
    304 TEST(SplitIterator, EdgeCases) {
    305  // Expected input and output, assuming a delimiter of ','
    306  struct {
    307    std::string in;
    308    std::vector<std::string> expect;
    309  } specs[] = {
    310      {"", {""}},
    311      {"foo", {"foo"}},
    312      {",", {"", ""}},
    313      {",foo", {"", "foo"}},
    314      {"foo,", {"foo", ""}},
    315      {",foo,", {"", "foo", ""}},
    316      {"foo,bar", {"foo", "bar"}},
    317  };
    318 
    319  for (const auto& spec : specs) {
    320    SCOPED_TRACE(spec.in);
    321    auto splitter = absl::StrSplit(spec.in, ',');
    322    auto it = splitter.begin();
    323    auto end = splitter.end();
    324    for (const auto& expected : spec.expect) {
    325      EXPECT_NE(it, end);
    326      EXPECT_EQ(expected, *it++);
    327    }
    328    EXPECT_EQ(it, end);
    329  }
    330 }
    331 
    332 TEST(Splitter, Const) {
    333  const auto splitter = absl::StrSplit("a,b,c", ',');
    334  EXPECT_THAT(splitter, ElementsAre("a", "b", "c"));
    335 }
    336 
    337 TEST(Split, EmptyAndNull) {
    338  // Attention: Splitting a null absl::string_view is different than splitting
    339  // an empty absl::string_view even though both string_views are considered
    340  // equal. This behavior is likely surprising and undesirable. However, to
    341  // maintain backward compatibility, there is a small "hack" in
    342  // str_split_internal.h that preserves this behavior. If that behavior is ever
    343  // changed/fixed, this test will need to be updated.
    344  EXPECT_THAT(absl::StrSplit(absl::string_view(""), '-'), ElementsAre(""));
    345  EXPECT_THAT(absl::StrSplit(absl::string_view(), '-'), ElementsAre());
    346 }
    347 
    348 TEST(SplitIterator, EqualityAsEndCondition) {
    349  auto splitter = absl::StrSplit("a,b,c", ',');
    350  auto it = splitter.begin();
    351  auto it2 = it;
    352 
    353  // Increments it2 twice to point to "c" in the input text.
    354  ++it2;
    355  ++it2;
    356  EXPECT_EQ("c", *it2);
    357 
    358  // This test uses a non-end SplitIterator as the terminating condition in a
    359  // for loop. This relies on SplitIterator equality for non-end SplitIterators
    360  // working correctly. At this point it2 points to "c", and we use that as the
    361  // "end" condition in this test.
    362  std::vector<absl::string_view> v;
    363  for (; it != it2; ++it) {
    364    v.push_back(*it);
    365  }
    366  EXPECT_THAT(v, ElementsAre("a", "b"));
    367 }
    368 
    369 //
    370 // Tests for Splitter
    371 //
    372 
    373 TEST(Splitter, RangeIterators) {
    374  auto splitter = absl::StrSplit("a,b,c", ',');
    375  std::vector<absl::string_view> output;
    376  for (absl::string_view p : splitter) {
    377    output.push_back(p);
    378  }
    379  EXPECT_THAT(output, ElementsAre("a", "b", "c"));
    380 }
    381 
    382 // Some template functions for use in testing conversion operators
    383 template <typename ContainerType, typename Splitter>
    384 void TestConversionOperator(const Splitter& splitter) {
    385  ContainerType output = splitter;
    386  EXPECT_THAT(output, UnorderedElementsAre("a", "b", "c", "d"));
    387 }
    388 
    389 template <typename MapType, typename Splitter>
    390 void TestMapConversionOperator(const Splitter& splitter) {
    391  MapType m = splitter;
    392  EXPECT_THAT(m, UnorderedElementsAre(Pair("a", "b"), Pair("c", "d")));
    393 }
    394 
    395 template <typename FirstType, typename SecondType, typename Splitter>
    396 void TestPairConversionOperator(const Splitter& splitter) {
    397  std::pair<FirstType, SecondType> p = splitter;
    398  EXPECT_EQ(p, (std::pair<FirstType, SecondType>("a", "b")));
    399 }
    400 
    401 template <typename StringType, typename Splitter>
    402 void TestArrayConversionOperator(const Splitter& splitter) {
    403  std::array<StringType, 2> a = splitter;
    404  EXPECT_THAT(a, ElementsAre("a", "b"));
    405 }
    406 
    407 TEST(Splitter, ConversionOperator) {
    408  auto splitter = absl::StrSplit("a,b,c,d", ',');
    409 
    410  TestConversionOperator<std::vector<absl::string_view>>(splitter);
    411  TestConversionOperator<std::vector<std::string>>(splitter);
    412  TestConversionOperator<std::list<absl::string_view>>(splitter);
    413  TestConversionOperator<std::list<std::string>>(splitter);
    414  TestConversionOperator<std::deque<absl::string_view>>(splitter);
    415  TestConversionOperator<std::deque<std::string>>(splitter);
    416  TestConversionOperator<std::set<absl::string_view>>(splitter);
    417  TestConversionOperator<std::set<std::string>>(splitter);
    418  TestConversionOperator<std::multiset<absl::string_view>>(splitter);
    419  TestConversionOperator<std::multiset<std::string>>(splitter);
    420  TestConversionOperator<absl::btree_set<absl::string_view>>(splitter);
    421  TestConversionOperator<absl::btree_set<std::string>>(splitter);
    422  TestConversionOperator<absl::btree_multiset<absl::string_view>>(splitter);
    423  TestConversionOperator<absl::btree_multiset<std::string>>(splitter);
    424  TestConversionOperator<std::unordered_set<std::string>>(splitter);
    425 
    426  // Tests conversion to map-like objects.
    427 
    428  TestMapConversionOperator<std::map<absl::string_view, absl::string_view>>(
    429      splitter);
    430  TestMapConversionOperator<std::map<absl::string_view, std::string>>(splitter);
    431  TestMapConversionOperator<std::map<std::string, absl::string_view>>(splitter);
    432  TestMapConversionOperator<std::map<std::string, std::string>>(splitter);
    433  TestMapConversionOperator<
    434      std::multimap<absl::string_view, absl::string_view>>(splitter);
    435  TestMapConversionOperator<std::multimap<absl::string_view, std::string>>(
    436      splitter);
    437  TestMapConversionOperator<std::multimap<std::string, absl::string_view>>(
    438      splitter);
    439  TestMapConversionOperator<std::multimap<std::string, std::string>>(splitter);
    440  TestMapConversionOperator<
    441      absl::btree_map<absl::string_view, absl::string_view>>(splitter);
    442  TestMapConversionOperator<absl::btree_map<absl::string_view, std::string>>(
    443      splitter);
    444  TestMapConversionOperator<absl::btree_map<std::string, absl::string_view>>(
    445      splitter);
    446  TestMapConversionOperator<absl::btree_map<std::string, std::string>>(
    447      splitter);
    448  TestMapConversionOperator<
    449      absl::btree_multimap<absl::string_view, absl::string_view>>(splitter);
    450  TestMapConversionOperator<
    451      absl::btree_multimap<absl::string_view, std::string>>(splitter);
    452  TestMapConversionOperator<
    453      absl::btree_multimap<std::string, absl::string_view>>(splitter);
    454  TestMapConversionOperator<absl::btree_multimap<std::string, std::string>>(
    455      splitter);
    456  TestMapConversionOperator<std::unordered_map<std::string, std::string>>(
    457      splitter);
    458  TestMapConversionOperator<
    459      absl::node_hash_map<absl::string_view, absl::string_view>>(splitter);
    460  TestMapConversionOperator<
    461      absl::node_hash_map<absl::string_view, std::string>>(splitter);
    462  TestMapConversionOperator<
    463      absl::node_hash_map<std::string, absl::string_view>>(splitter);
    464  TestMapConversionOperator<
    465      absl::flat_hash_map<absl::string_view, absl::string_view>>(splitter);
    466  TestMapConversionOperator<
    467      absl::flat_hash_map<absl::string_view, std::string>>(splitter);
    468  TestMapConversionOperator<
    469      absl::flat_hash_map<std::string, absl::string_view>>(splitter);
    470 
    471  // Tests conversion to std::pair
    472 
    473  TestPairConversionOperator<absl::string_view, absl::string_view>(splitter);
    474  TestPairConversionOperator<absl::string_view, std::string>(splitter);
    475  TestPairConversionOperator<std::string, absl::string_view>(splitter);
    476  TestPairConversionOperator<std::string, std::string>(splitter);
    477 
    478  // Tests conversion to std::array
    479  TestArrayConversionOperator<std::string>(splitter);
    480  TestArrayConversionOperator<absl::string_view>(splitter);
    481 }
    482 
    483 // A few additional tests for conversion to std::pair. This conversion is
    484 // different from others because a std::pair always has exactly two elements:
    485 // .first and .second. The split has to work even when the split has
    486 // less-than, equal-to, and more-than 2 strings.
    487 TEST(Splitter, ToPair) {
    488  {
    489    // Empty string
    490    std::pair<std::string, std::string> p = absl::StrSplit("", ',');
    491    EXPECT_EQ("", p.first);
    492    EXPECT_EQ("", p.second);
    493  }
    494 
    495  {
    496    // Only first
    497    std::pair<std::string, std::string> p = absl::StrSplit("a", ',');
    498    EXPECT_EQ("a", p.first);
    499    EXPECT_EQ("", p.second);
    500  }
    501 
    502  {
    503    // Only second
    504    std::pair<std::string, std::string> p = absl::StrSplit(",b", ',');
    505    EXPECT_EQ("", p.first);
    506    EXPECT_EQ("b", p.second);
    507  }
    508 
    509  {
    510    // First and second.
    511    std::pair<std::string, std::string> p = absl::StrSplit("a,b", ',');
    512    EXPECT_EQ("a", p.first);
    513    EXPECT_EQ("b", p.second);
    514  }
    515 
    516  {
    517    // First and second and then more stuff that will be ignored.
    518    std::pair<std::string, std::string> p = absl::StrSplit("a,b,c", ',');
    519    EXPECT_EQ("a", p.first);
    520    EXPECT_EQ("b", p.second);
    521    // "c" is omitted.
    522  }
    523 }
    524 
    525 // std::array tests similar to std::pair tests above, testing fewer, exactly,
    526 // or more elements than the array size.
    527 TEST(Splitter, ToArray) {
    528  {
    529    // Empty string
    530    std::array<std::string, 2> p = absl::StrSplit("", ',');
    531    EXPECT_THAT(p, ElementsAre("", ""));
    532  }
    533 
    534  {
    535    // Only first
    536    std::array<std::string, 2> p = absl::StrSplit("a", ',');
    537    EXPECT_THAT(p, ElementsAre("a", ""));
    538  }
    539 
    540  {
    541    // Only second
    542    std::array<std::string, 2> p = absl::StrSplit(",b", ',');
    543    EXPECT_THAT(p, ElementsAre("", "b"));
    544  }
    545 
    546  {
    547    // First and second.
    548    std::array<std::string, 2> p = absl::StrSplit("a,b", ',');
    549    EXPECT_THAT(p, ElementsAre("a", "b"));
    550  }
    551 
    552  {
    553    // First and second and then more stuff that will be ignored.
    554    std::array<std::string, 2> p = absl::StrSplit("a,b,c", ',');
    555    EXPECT_THAT(p, ElementsAre("a", "b"));
    556    // "c" is omitted.
    557  }
    558 }
    559 
    560 TEST(Splitter, Predicates) {
    561  static const char kTestChars[] = ",a, ,b,";
    562  using absl::AllowEmpty;
    563  using absl::SkipEmpty;
    564  using absl::SkipWhitespace;
    565 
    566  {
    567    // No predicate. Does not skip empties.
    568    auto splitter = absl::StrSplit(kTestChars, ',');
    569    std::vector<std::string> v = splitter;
    570    EXPECT_THAT(v, ElementsAre("", "a", " ", "b", ""));
    571  }
    572 
    573  {
    574    // Allows empty strings. Same behavior as no predicate at all.
    575    auto splitter = absl::StrSplit(kTestChars, ',', AllowEmpty());
    576    std::vector<std::string> v_allowempty = splitter;
    577    EXPECT_THAT(v_allowempty, ElementsAre("", "a", " ", "b", ""));
    578 
    579    // Ensures AllowEmpty equals the behavior with no predicate.
    580    auto splitter_nopredicate = absl::StrSplit(kTestChars, ',');
    581    std::vector<std::string> v_nopredicate = splitter_nopredicate;
    582    EXPECT_EQ(v_allowempty, v_nopredicate);
    583  }
    584 
    585  {
    586    // Skips empty strings.
    587    auto splitter = absl::StrSplit(kTestChars, ',', SkipEmpty());
    588    std::vector<std::string> v = splitter;
    589    EXPECT_THAT(v, ElementsAre("a", " ", "b"));
    590  }
    591 
    592  {
    593    // Skips empty and all-whitespace strings.
    594    auto splitter = absl::StrSplit(kTestChars, ',', SkipWhitespace());
    595    std::vector<std::string> v = splitter;
    596    EXPECT_THAT(v, ElementsAre("a", "b"));
    597  }
    598 }
    599 
    600 //
    601 // Tests for StrSplit()
    602 //
    603 
    604 TEST(Split, Basics) {
    605  {
    606    // Doesn't really do anything useful because the return value is ignored,
    607    // but it should work.
    608    absl::StrSplit("a,b,c", ',');
    609  }
    610 
    611  {
    612    std::vector<absl::string_view> v = absl::StrSplit("a,b,c", ',');
    613    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    614  }
    615 
    616  {
    617    std::vector<std::string> v = absl::StrSplit("a,b,c", ',');
    618    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    619  }
    620 
    621  {
    622    // Ensures that assignment works. This requires a little extra work with
    623    // C++11 because of overloads with initializer_list.
    624    std::vector<std::string> v;
    625    v = absl::StrSplit("a,b,c", ',');
    626 
    627    EXPECT_THAT(v, ElementsAre("a", "b", "c"));
    628    std::map<std::string, std::string> m;
    629    m = absl::StrSplit("a,b,c", ',');
    630    EXPECT_EQ(2, m.size());
    631    std::unordered_map<std::string, std::string> hm;
    632    hm = absl::StrSplit("a,b,c", ',');
    633    EXPECT_EQ(2, hm.size());
    634  }
    635 }
    636 
    637 absl::string_view ReturnStringView() { return "Hello World"; }
    638 const char* ReturnConstCharP() { return "Hello World"; }
    639 char* ReturnCharP() { return const_cast<char*>("Hello World"); }
    640 
    641 TEST(Split, AcceptsCertainTemporaries) {
    642  std::vector<std::string> v;
    643  v = absl::StrSplit(ReturnStringView(), ' ');
    644  EXPECT_THAT(v, ElementsAre("Hello", "World"));
    645  v = absl::StrSplit(ReturnConstCharP(), ' ');
    646  EXPECT_THAT(v, ElementsAre("Hello", "World"));
    647  v = absl::StrSplit(ReturnCharP(), ' ');
    648  EXPECT_THAT(v, ElementsAre("Hello", "World"));
    649 }
    650 
    651 TEST(Split, Temporary) {
    652  // Use a std::string longer than the SSO length, so that when the temporary is
    653  // destroyed, if the splitter keeps a reference to the string's contents,
    654  // it'll reference freed memory instead of just dead on-stack memory.
    655  const char input[] = "a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u";
    656  EXPECT_LT(sizeof(std::string), ABSL_ARRAYSIZE(input))
    657      << "Input should be larger than fits on the stack.";
    658 
    659  // This happens more often in C++11 as part of a range-based for loop.
    660  auto splitter = absl::StrSplit(std::string(input), ',');
    661  std::string expected = "a";
    662  for (absl::string_view letter : splitter) {
    663    EXPECT_EQ(expected, letter);
    664    ++expected[0];
    665  }
    666  EXPECT_EQ("v", expected);
    667 
    668  // This happens more often in C++11 as part of a range-based for loop.
    669  auto std_splitter = absl::StrSplit(std::string(input), ',');
    670  expected = "a";
    671  for (absl::string_view letter : std_splitter) {
    672    EXPECT_EQ(expected, letter);
    673    ++expected[0];
    674  }
    675  EXPECT_EQ("v", expected);
    676 }
    677 
    678 template <typename T>
    679 static std::unique_ptr<T> CopyToHeap(const T& value) {
    680  return std::unique_ptr<T>(new T(value));
    681 }
    682 
    683 TEST(Split, LvalueCaptureIsCopyable) {
    684  std::string input = "a,b";
    685  auto heap_splitter = CopyToHeap(absl::StrSplit(input, ','));
    686  auto stack_splitter = *heap_splitter;
    687  heap_splitter.reset();
    688  std::vector<std::string> result = stack_splitter;
    689  EXPECT_THAT(result, testing::ElementsAre("a", "b"));
    690 }
    691 
    692 TEST(Split, TemporaryCaptureIsCopyable) {
    693  auto heap_splitter = CopyToHeap(absl::StrSplit(std::string("a,b"), ','));
    694  auto stack_splitter = *heap_splitter;
    695  heap_splitter.reset();
    696  std::vector<std::string> result = stack_splitter;
    697  EXPECT_THAT(result, testing::ElementsAre("a", "b"));
    698 }
    699 
    700 TEST(Split, SplitterIsCopyableAndMoveable) {
    701  auto a = absl::StrSplit("foo", '-');
    702 
    703  // Ensures that the following expressions compile.
    704  auto b = a;             // Copy construct
    705  auto c = std::move(a);  // Move construct
    706  b = c;                  // Copy assign
    707  c = std::move(b);       // Move assign
    708 
    709  EXPECT_THAT(c, ElementsAre("foo"));
    710 }
    711 
    712 TEST(Split, StringDelimiter) {
    713  {
    714    std::vector<absl::string_view> v = absl::StrSplit("a,b", ',');
    715    EXPECT_THAT(v, ElementsAre("a", "b"));
    716  }
    717 
    718  {
    719    std::vector<absl::string_view> v = absl::StrSplit("a,b", std::string(","));
    720    EXPECT_THAT(v, ElementsAre("a", "b"));
    721  }
    722 
    723  {
    724    std::vector<absl::string_view> v =
    725        absl::StrSplit("a,b", absl::string_view(","));
    726    EXPECT_THAT(v, ElementsAre("a", "b"));
    727  }
    728 }
    729 
    730 #if !defined(__cpp_char8_t)
    731 #if defined(__clang__)
    732 #pragma clang diagnostic push
    733 #pragma clang diagnostic ignored "-Wc++2a-compat"
    734 #endif
    735 TEST(Split, UTF8) {
    736  // Tests splitting utf8 strings and utf8 delimiters.
    737  std::string utf8_string = u8"\u03BA\u1F79\u03C3\u03BC\u03B5";
    738  {
    739    // A utf8 input string with an ascii delimiter.
    740    std::string to_split = "a," + utf8_string;
    741    std::vector<absl::string_view> v = absl::StrSplit(to_split, ',');
    742    EXPECT_THAT(v, ElementsAre("a", utf8_string));
    743  }
    744 
    745  {
    746    // A utf8 input string and a utf8 delimiter.
    747    std::string to_split = "a," + utf8_string + ",b";
    748    std::string unicode_delimiter = "," + utf8_string + ",";
    749    std::vector<absl::string_view> v =
    750        absl::StrSplit(to_split, unicode_delimiter);
    751    EXPECT_THAT(v, ElementsAre("a", "b"));
    752  }
    753 
    754  {
    755    // A utf8 input string and ByAnyChar with ascii chars.
    756    std::vector<absl::string_view> v =
    757        absl::StrSplit(u8"Foo h\u00E4llo th\u4E1Ere", absl::ByAnyChar(" \t"));
    758    EXPECT_THAT(v, ElementsAre("Foo", u8"h\u00E4llo", u8"th\u4E1Ere"));
    759  }
    760 }
    761 #if defined(__clang__)
    762 #pragma clang diagnostic pop
    763 #endif
    764 #endif  // !defined(__cpp_char8_t)
    765 
    766 TEST(Split, EmptyStringDelimiter) {
    767  {
    768    std::vector<std::string> v = absl::StrSplit("", "");
    769    EXPECT_THAT(v, ElementsAre(""));
    770  }
    771 
    772  {
    773    std::vector<std::string> v = absl::StrSplit("a", "");
    774    EXPECT_THAT(v, ElementsAre("a"));
    775  }
    776 
    777  {
    778    std::vector<std::string> v = absl::StrSplit("ab", "");
    779    EXPECT_THAT(v, ElementsAre("a", "b"));
    780  }
    781 
    782  {
    783    std::vector<std::string> v = absl::StrSplit("a b", "");
    784    EXPECT_THAT(v, ElementsAre("a", " ", "b"));
    785  }
    786 }
    787 
    788 TEST(Split, SubstrDelimiter) {
    789  std::vector<absl::string_view> results;
    790  absl::string_view delim("//");
    791 
    792  results = absl::StrSplit("", delim);
    793  EXPECT_THAT(results, ElementsAre(""));
    794 
    795  results = absl::StrSplit("//", delim);
    796  EXPECT_THAT(results, ElementsAre("", ""));
    797 
    798  results = absl::StrSplit("ab", delim);
    799  EXPECT_THAT(results, ElementsAre("ab"));
    800 
    801  results = absl::StrSplit("ab//", delim);
    802  EXPECT_THAT(results, ElementsAre("ab", ""));
    803 
    804  results = absl::StrSplit("ab/", delim);
    805  EXPECT_THAT(results, ElementsAre("ab/"));
    806 
    807  results = absl::StrSplit("a/b", delim);
    808  EXPECT_THAT(results, ElementsAre("a/b"));
    809 
    810  results = absl::StrSplit("a//b", delim);
    811  EXPECT_THAT(results, ElementsAre("a", "b"));
    812 
    813  results = absl::StrSplit("a///b", delim);
    814  EXPECT_THAT(results, ElementsAre("a", "/b"));
    815 
    816  results = absl::StrSplit("a////b", delim);
    817  EXPECT_THAT(results, ElementsAre("a", "", "b"));
    818 }
    819 
    820 TEST(Split, EmptyResults) {
    821  std::vector<absl::string_view> results;
    822 
    823  results = absl::StrSplit("", '#');
    824  EXPECT_THAT(results, ElementsAre(""));
    825 
    826  results = absl::StrSplit("#", '#');
    827  EXPECT_THAT(results, ElementsAre("", ""));
    828 
    829  results = absl::StrSplit("#cd", '#');
    830  EXPECT_THAT(results, ElementsAre("", "cd"));
    831 
    832  results = absl::StrSplit("ab#cd#", '#');
    833  EXPECT_THAT(results, ElementsAre("ab", "cd", ""));
    834 
    835  results = absl::StrSplit("ab##cd", '#');
    836  EXPECT_THAT(results, ElementsAre("ab", "", "cd"));
    837 
    838  results = absl::StrSplit("ab##", '#');
    839  EXPECT_THAT(results, ElementsAre("ab", "", ""));
    840 
    841  results = absl::StrSplit("ab#ab#", '#');
    842  EXPECT_THAT(results, ElementsAre("ab", "ab", ""));
    843 
    844  results = absl::StrSplit("aaaa", 'a');
    845  EXPECT_THAT(results, ElementsAre("", "", "", "", ""));
    846 
    847  results = absl::StrSplit("", '#', absl::SkipEmpty());
    848  EXPECT_THAT(results, ElementsAre());
    849 }
    850 
    851 template <typename Delimiter>
    852 static bool IsFoundAtStartingPos(absl::string_view text, Delimiter d,
    853                                 size_t starting_pos, int expected_pos) {
    854  absl::string_view found = d.Find(text, starting_pos);
    855  return found.data() != text.data() + text.size() &&
    856         expected_pos == found.data() - text.data();
    857 }
    858 
    859 // Helper function for testing Delimiter objects. Returns true if the given
    860 // Delimiter is found in the given string at the given position. This function
    861 // tests two cases:
    862 //   1. The actual text given, staring at position 0
    863 //   2. The text given with leading padding that should be ignored
    864 template <typename Delimiter>
    865 static bool IsFoundAt(absl::string_view text, Delimiter d, int expected_pos) {
    866  const std::string leading_text = ",x,y,z,";
    867  return IsFoundAtStartingPos(text, d, 0, expected_pos) &&
    868         IsFoundAtStartingPos(leading_text + std::string(text), d,
    869                              leading_text.length(),
    870                              expected_pos + leading_text.length());
    871 }
    872 
    873 //
    874 // Tests for ByString
    875 //
    876 
    877 // Tests using any delimiter that represents a single comma.
    878 template <typename Delimiter>
    879 void TestComma(Delimiter d) {
    880  EXPECT_TRUE(IsFoundAt(",", d, 0));
    881  EXPECT_TRUE(IsFoundAt("a,", d, 1));
    882  EXPECT_TRUE(IsFoundAt(",b", d, 0));
    883  EXPECT_TRUE(IsFoundAt("a,b", d, 1));
    884  EXPECT_TRUE(IsFoundAt("a,b,", d, 1));
    885  EXPECT_TRUE(IsFoundAt("a,b,c", d, 1));
    886  EXPECT_FALSE(IsFoundAt("", d, -1));
    887  EXPECT_FALSE(IsFoundAt(" ", d, -1));
    888  EXPECT_FALSE(IsFoundAt("a", d, -1));
    889  EXPECT_FALSE(IsFoundAt("a b c", d, -1));
    890  EXPECT_FALSE(IsFoundAt("a;b;c", d, -1));
    891  EXPECT_FALSE(IsFoundAt(";", d, -1));
    892 }
    893 
    894 TEST(Delimiter, ByString) {
    895  using absl::ByString;
    896  TestComma(ByString(","));
    897 
    898  // Works as named variable.
    899  ByString comma_string(",");
    900  TestComma(comma_string);
    901 
    902  // The first occurrence of empty string ("") in a string is at position 0.
    903  // There is a test below that demonstrates this for absl::string_view::find().
    904  // If the ByString delimiter returned position 0 for this, there would
    905  // be an infinite loop in the SplitIterator code. To avoid this, empty string
    906  // is a special case in that it always returns the item at position 1.
    907  absl::string_view abc("abc");
    908  EXPECT_EQ(0, abc.find(""));  // "" is found at position 0
    909  ByString empty("");
    910  EXPECT_FALSE(IsFoundAt("", empty, 0));
    911  EXPECT_FALSE(IsFoundAt("a", empty, 0));
    912  EXPECT_TRUE(IsFoundAt("ab", empty, 1));
    913  EXPECT_TRUE(IsFoundAt("abc", empty, 1));
    914 }
    915 
    916 TEST(Split, ByChar) {
    917  using absl::ByChar;
    918  TestComma(ByChar(','));
    919 
    920  // Works as named variable.
    921  ByChar comma_char(',');
    922  TestComma(comma_char);
    923 }
    924 
    925 //
    926 // Tests for ByAnyChar
    927 //
    928 
    929 TEST(Delimiter, ByAnyChar) {
    930  using absl::ByAnyChar;
    931  ByAnyChar one_delim(",");
    932  // Found
    933  EXPECT_TRUE(IsFoundAt(",", one_delim, 0));
    934  EXPECT_TRUE(IsFoundAt("a,", one_delim, 1));
    935  EXPECT_TRUE(IsFoundAt("a,b", one_delim, 1));
    936  EXPECT_TRUE(IsFoundAt(",b", one_delim, 0));
    937  // Not found
    938  EXPECT_FALSE(IsFoundAt("", one_delim, -1));
    939  EXPECT_FALSE(IsFoundAt(" ", one_delim, -1));
    940  EXPECT_FALSE(IsFoundAt("a", one_delim, -1));
    941  EXPECT_FALSE(IsFoundAt("a;b;c", one_delim, -1));
    942  EXPECT_FALSE(IsFoundAt(";", one_delim, -1));
    943 
    944  ByAnyChar two_delims(",;");
    945  // Found
    946  EXPECT_TRUE(IsFoundAt(",", two_delims, 0));
    947  EXPECT_TRUE(IsFoundAt(";", two_delims, 0));
    948  EXPECT_TRUE(IsFoundAt(",;", two_delims, 0));
    949  EXPECT_TRUE(IsFoundAt(";,", two_delims, 0));
    950  EXPECT_TRUE(IsFoundAt(",;b", two_delims, 0));
    951  EXPECT_TRUE(IsFoundAt(";,b", two_delims, 0));
    952  EXPECT_TRUE(IsFoundAt("a;,", two_delims, 1));
    953  EXPECT_TRUE(IsFoundAt("a,;", two_delims, 1));
    954  EXPECT_TRUE(IsFoundAt("a;,b", two_delims, 1));
    955  EXPECT_TRUE(IsFoundAt("a,;b", two_delims, 1));
    956  // Not found
    957  EXPECT_FALSE(IsFoundAt("", two_delims, -1));
    958  EXPECT_FALSE(IsFoundAt(" ", two_delims, -1));
    959  EXPECT_FALSE(IsFoundAt("a", two_delims, -1));
    960  EXPECT_FALSE(IsFoundAt("a=b=c", two_delims, -1));
    961  EXPECT_FALSE(IsFoundAt("=", two_delims, -1));
    962 
    963  // ByAnyChar behaves just like ByString when given a delimiter of empty
    964  // string. That is, it always returns a zero-length absl::string_view
    965  // referring to the item at position 1, not position 0.
    966  ByAnyChar empty("");
    967  EXPECT_FALSE(IsFoundAt("", empty, 0));
    968  EXPECT_FALSE(IsFoundAt("a", empty, 0));
    969  EXPECT_TRUE(IsFoundAt("ab", empty, 1));
    970  EXPECT_TRUE(IsFoundAt("abc", empty, 1));
    971 }
    972 
    973 //
    974 // Tests for ByAsciiWhitespace
    975 //
    976 TEST(Split, ByAsciiWhitespace) {
    977  using absl::ByAsciiWhitespace;
    978  using absl::SkipEmpty;
    979  std::vector<absl::string_view> results;
    980 
    981  results = absl::StrSplit("aaaa\n", ByAsciiWhitespace());
    982  EXPECT_THAT(results, ElementsAre("aaaa", ""));
    983 
    984  results = absl::StrSplit("aaaa\n", ByAsciiWhitespace(), SkipEmpty());
    985  EXPECT_THAT(results, ElementsAre("aaaa"));
    986 
    987  results = absl::StrSplit(" ", ByAsciiWhitespace());
    988  EXPECT_THAT(results, ElementsAre("", ""));
    989 
    990  results = absl::StrSplit(" ", ByAsciiWhitespace(), SkipEmpty());
    991  EXPECT_THAT(results, IsEmpty());
    992 
    993  results = absl::StrSplit("a", ByAsciiWhitespace());
    994  EXPECT_THAT(results, ElementsAre("a"));
    995 
    996  results = absl::StrSplit("", ByAsciiWhitespace());
    997  EXPECT_THAT(results, ElementsAre(""));
    998 
    999  results = absl::StrSplit("", ByAsciiWhitespace(), SkipEmpty());
   1000  EXPECT_THAT(results, IsEmpty());
   1001 
   1002  results = absl::StrSplit("a b\tc\n  d\n", ByAsciiWhitespace());
   1003  EXPECT_THAT(results, ElementsAre("a", "b", "c", "", "", "d", ""));
   1004 
   1005  results = absl::StrSplit("a b\tc\n  d  \n", ByAsciiWhitespace(), SkipEmpty());
   1006  EXPECT_THAT(results, ElementsAre("a", "b", "c", "d"));
   1007 
   1008  results = absl::StrSplit("a\t\n\v\f\r b", ByAsciiWhitespace(), SkipEmpty());
   1009  EXPECT_THAT(results, ElementsAre("a", "b"));
   1010 }
   1011 
   1012 //
   1013 // Tests for ByLength
   1014 //
   1015 
   1016 TEST(Delimiter, ByLength) {
   1017  using absl::ByLength;
   1018 
   1019  ByLength four_char_delim(4);
   1020 
   1021  // Found
   1022  EXPECT_TRUE(IsFoundAt("abcde", four_char_delim, 4));
   1023  EXPECT_TRUE(IsFoundAt("abcdefghijklmnopqrstuvwxyz", four_char_delim, 4));
   1024  EXPECT_TRUE(IsFoundAt("a b,c\nd", four_char_delim, 4));
   1025  // Not found
   1026  EXPECT_FALSE(IsFoundAt("", four_char_delim, 0));
   1027  EXPECT_FALSE(IsFoundAt("a", four_char_delim, 0));
   1028  EXPECT_FALSE(IsFoundAt("ab", four_char_delim, 0));
   1029  EXPECT_FALSE(IsFoundAt("abc", four_char_delim, 0));
   1030  EXPECT_FALSE(IsFoundAt("abcd", four_char_delim, 0));
   1031 }
   1032 
   1033 TEST(Split, WorksWithLargeStrings) {
   1034 #if defined(ABSL_HAVE_ADDRESS_SANITIZER) || \
   1035    defined(ABSL_HAVE_MEMORY_SANITIZER) || defined(ABSL_HAVE_THREAD_SANITIZER)
   1036  constexpr size_t kSize = (uint32_t{1} << 26) + 1;  // 64M + 1 byte
   1037 #else
   1038  constexpr size_t kSize = (uint32_t{1} << 31) + 1;  // 2G + 1 byte
   1039 #endif
   1040  if (sizeof(size_t) > 4) {
   1041    std::string s(kSize, 'x');
   1042    s.back() = '-';
   1043    std::vector<absl::string_view> v = absl::StrSplit(s, '-');
   1044    EXPECT_EQ(2, v.size());
   1045    // The first element will contain 2G of 'x's.
   1046    // testing::StartsWith is too slow with a 2G string.
   1047    EXPECT_EQ('x', v[0][0]);
   1048    EXPECT_EQ('x', v[0][1]);
   1049    EXPECT_EQ('x', v[0][3]);
   1050    EXPECT_EQ("", v[1]);
   1051  }
   1052 }
   1053 
   1054 TEST(SplitInternalTest, TypeTraits) {
   1055  EXPECT_FALSE(absl::strings_internal::HasMappedType<int>::value);
   1056  EXPECT_TRUE(
   1057      (absl::strings_internal::HasMappedType<std::map<int, int>>::value));
   1058  EXPECT_FALSE(absl::strings_internal::HasValueType<int>::value);
   1059  EXPECT_TRUE(
   1060      (absl::strings_internal::HasValueType<std::map<int, int>>::value));
   1061  EXPECT_FALSE(absl::strings_internal::HasConstIterator<int>::value);
   1062  EXPECT_TRUE(
   1063      (absl::strings_internal::HasConstIterator<std::map<int, int>>::value));
   1064  EXPECT_FALSE(absl::strings_internal::IsInitializerList<int>::value);
   1065  EXPECT_TRUE((absl::strings_internal::IsInitializerList<
   1066               std::initializer_list<int>>::value));
   1067 }
   1068 
   1069 }  // namespace