Added ByAsciiWhitespace to str_split library.

PiperOrigin-RevId: 592653487
Change-Id: Iddd2f484807cb02dd2ee8bba26c22d196be02c88

absl/strings/str_split.cc

@@ -96,6 +96,11 @@ absl::string_view ByString::Find(absl::string_view text, size_t pos) const {
   return GenericFind(text, delimiter_, pos, LiteralPolicy());
 }
 
+absl::string_view ByAsciiWhitespace::Find(absl::string_view text,
+                                          size_t pos) const {
+  return GenericFind(text, " \t\v\f\r\n", pos, AnyOfPolicy());
+}
+
 //
 // ByChar
 //

absl/strings/str_split.h

@@ -130,6 +130,24 @@ class ByString {
   const std::string delimiter_;
 };
 
+// ByAsciiWhitespace
+//
+// A sub-string delimiter that splits by ASCII whitespace
+// (space, tab, vertical tab, formfeed, linefeed, or carriage return).
+// Note: you probably want to use absl::SkipEmpty() as well!
+//
+// This class is equivalent to ByAnyChar with ASCII whitespace chars.
+//
+// Example:
+//
+//   std::vector<std::string> v = absl::StrSplit(
+//       "a b\tc\n  d  \n", absl::ByAsciiWhitespace(), absl::SkipEmpty());
+//   // v[0] == "a", v[1] == "b", v[2] == "c", v[3] == "d"
+class ByAsciiWhitespace {
+ public:
+  absl::string_view Find(absl::string_view text, size_t pos) const;
+};
+
 // ByChar
 //
 // A single character delimiter. `ByChar` is functionally equivalent to a

absl/strings/str_split_test.cc

@@ -40,6 +40,7 @@
 namespace {
 
 using ::testing::ElementsAre;
+using ::testing::IsEmpty;
 using ::testing::Pair;
 using ::testing::UnorderedElementsAre;
 
@@ -923,6 +924,45 @@ TEST(Delimiter, ByAnyChar) {
   EXPECT_TRUE(IsFoundAt("abc", empty, 1));
 }
 
+//
+// Tests for ByAsciiWhitespace
+//
+TEST(Split, ByAsciiWhitespace) {
+  using absl::ByAsciiWhitespace;
+  using absl::SkipEmpty;
+  std::vector<absl::string_view> results;
+
+  results = absl::StrSplit("aaaa\n", ByAsciiWhitespace());
+  EXPECT_THAT(results, ElementsAre("aaaa", ""));
+
+  results = absl::StrSplit("aaaa\n", ByAsciiWhitespace(), SkipEmpty());
+  EXPECT_THAT(results, ElementsAre("aaaa"));
+
+  results = absl::StrSplit(" ", ByAsciiWhitespace());
+  EXPECT_THAT(results, ElementsAre("", ""));
+
+  results = absl::StrSplit(" ", ByAsciiWhitespace(), SkipEmpty());
+  EXPECT_THAT(results, IsEmpty());
+
+  results = absl::StrSplit("a", ByAsciiWhitespace());
+  EXPECT_THAT(results, ElementsAre("a"));
+
+  results = absl::StrSplit("", ByAsciiWhitespace());
+  EXPECT_THAT(results, ElementsAre(""));
+
+  results = absl::StrSplit("", ByAsciiWhitespace(), SkipEmpty());
+  EXPECT_THAT(results, IsEmpty());
+
+  results = absl::StrSplit("a b\tc\n  d\n", ByAsciiWhitespace());
+  EXPECT_THAT(results, ElementsAre("a", "b", "c", "", "", "d", ""));
+
+  results = absl::StrSplit("a b\tc\n  d  \n", ByAsciiWhitespace(), SkipEmpty());
+  EXPECT_THAT(results, ElementsAre("a", "b", "c", "d"));
+
+  results = absl::StrSplit("a\t\n\v\f\r b", ByAsciiWhitespace(), SkipEmpty());
+  EXPECT_THAT(results, ElementsAre("a", "b"));
+}
+
 //
 // Tests for ByLength
 //