Added StrContains, StartsWith, and EndsWith functions to str_util.h.

Marked contains, starts_with, ends_with, and consume StringPiece methods as deprecated.

This will allow tensorflow::StringPiece to be more easily replaced with absl::string_view (once the deprecated methods are removed) as absl::string_view does not contain those methods.

PiperOrigin-RevId: 189355316

4 files changed, 90 insertions, 2 deletions

diff --git a/tensorflow/core/lib/core/stringpiece.h b/tensorflow/core/lib/core/stringpiece.h
index 910e4d9e2a..79409cce4b 100644
--- a/tensorflow/core/lib/core/stringpiece.h
+++ b/tensorflow/core/lib/core/stringpiece.h
@@ -88,11 +88,13 @@ class StringPiece {
 
   size_t find(char c, size_t pos = 0) const;
   size_t rfind(char c, size_t pos = npos) const;
+  // DEPRECATED: Use tensorflow::str_util::StrContains instead.
   bool contains(StringPiece s) const;
 
   // Checks whether StringPiece starts with x and if so advances the beginning
   // of it to past the match.  It's basically a shortcut for starts_with
   // followed by remove_prefix.
+  // DEPRECATED: Use tensorflow::str_util::ConsumePrefix instead.
   bool Consume(StringPiece x) {
     if (starts_with(x)) {
       remove_prefix(x.size_);
@@ -113,10 +115,12 @@ class StringPiece {
   int compare(StringPiece b) const;
 
   // Return true iff "x" is a prefix of "*this"
+  // DEPRECATED: Use tensorflow::str_util::StartsWith instead.
   bool starts_with(StringPiece x) const {
     return ((size_ >= x.size_) && (memcmp(data_, x.data_, x.size_) == 0));
   }
   // Return true iff "x" is a suffix of "*this"
+  // DEPRECATED: Use tensorflow::str_util::EndsWith instead.
   bool ends_with(StringPiece x) const {
     return ((size_ >= x.size_) &&
             (memcmp(data_ + (size_ - x.size_), x.data_, x.size_) == 0));
diff --git a/tensorflow/core/lib/strings/str_util.cc b/tensorflow/core/lib/strings/str_util.cc
index d28857803d..9dbb74f6b8 100644
--- a/tensorflow/core/lib/strings/str_util.cc
+++ b/tensorflow/core/lib/strings/str_util.cc
@@ -373,7 +373,7 @@ size_t RemoveWhitespaceContext(StringPiece* text) {
 }
 
 bool ConsumePrefix(StringPiece* s, StringPiece expected) {
-  if (s->starts_with(expected)) {
+  if (StartsWith(*s, expected)) {
     s->remove_prefix(expected.size());
     return true;
   }
@@ -381,7 +381,7 @@ bool ConsumePrefix(StringPiece* s, StringPiece expected) {
 }
 
 bool ConsumeSuffix(StringPiece* s, StringPiece expected) {
-  if (s->ends_with(expected)) {
+  if (EndsWith(*s, expected)) {
     s->remove_suffix(expected.size());
     return true;
   }
@@ -452,5 +452,22 @@ bool SplitAndParseAsFloats(StringPiece text, char delim,
                                     result);
 }
 
+bool StrContains(StringPiece haystack, StringPiece needle) {
+  return std::search(haystack.begin(), haystack.end(), needle.begin(),
+                     needle.end()) != haystack.end();
+}
+
+bool StartsWith(StringPiece text, StringPiece prefix) {
+  return prefix.empty() ||
+         (text.size() >= prefix.size() &&
+          memcmp(text.data(), prefix.data(), prefix.size()) == 0);
+}
+
+bool EndsWith(StringPiece text, StringPiece suffix) {
+  return suffix.empty() || (text.size() >= suffix.size() &&
+                            memcmp(text.data() + (text.size() - suffix.size()),
+                                   suffix.data(), suffix.size()) == 0);
+}
+
 }  // namespace str_util
 }  // namespace tensorflow
diff --git a/tensorflow/core/lib/strings/str_util.h b/tensorflow/core/lib/strings/str_util.h
index 44c52850fa..f062eddef8 100644
--- a/tensorflow/core/lib/strings/str_util.h
+++ b/tensorflow/core/lib/strings/str_util.h
@@ -141,6 +141,21 @@ bool SplitAndParseAsInts(StringPiece text, char delim,
 bool SplitAndParseAsFloats(StringPiece text, char delim,
                            std::vector<float>* result);
 
+// StartsWith()
+//
+// Returns whether a given string `text` begins with `prefix`.
+bool StartsWith(StringPiece text, StringPiece prefix);
+
+// EndsWith()
+//
+// Returns whether a given string `text` ends with `suffix`.
+bool EndsWith(StringPiece text, StringPiece suffix);
+
+// StrContains()
+//
+// Returns whether a given string `haystack` contains the substring `needle`.
+bool StrContains(StringPiece haystack, StringPiece needle);
+
 // ------------------------------------------------------------------
 // Implementation details below
 template <typename T>
diff --git a/tensorflow/core/lib/strings/str_util_test.cc b/tensorflow/core/lib/strings/str_util_test.cc
index 6d461241f7..63643c3e8e 100644
--- a/tensorflow/core/lib/strings/str_util_test.cc
+++ b/tensorflow/core/lib/strings/str_util_test.cc
@@ -430,4 +430,56 @@ TEST(StringReplace, EmptyStringReplaceAll) {
   EXPECT_EQ("", str_util::StringReplace("", "a", "X", /*replace_all=*/true));
 }
 
+TEST(StartsWith, Basic) {
+  const string s1(
+      "123"
+      "\0"
+      "456",
+      7);
+  const StringPiece a("foobar");
+  const StringPiece b(s1);
+  const StringPiece e;
+  EXPECT_TRUE(str_util::StartsWith(a, a));
+  EXPECT_TRUE(str_util::StartsWith(a, "foo"));
+  EXPECT_TRUE(str_util::StartsWith(a, e));
+  EXPECT_TRUE(str_util::StartsWith(b, s1));
+  EXPECT_TRUE(str_util::StartsWith(b, b));
+  EXPECT_TRUE(str_util::StartsWith(b, e));
+  EXPECT_TRUE(str_util::StartsWith(e, ""));
+  EXPECT_FALSE(str_util::StartsWith(a, b));
+  EXPECT_FALSE(str_util::StartsWith(b, a));
+  EXPECT_FALSE(str_util::StartsWith(e, a));
+}
+
+TEST(EndsWith, Basic) {
+  const string s1(
+      "123"
+      "\0"
+      "456",
+      7);
+  const StringPiece a("foobar");
+  const StringPiece b(s1);
+  const StringPiece e;
+  EXPECT_TRUE(str_util::EndsWith(a, a));
+  EXPECT_TRUE(str_util::EndsWith(a, "bar"));
+  EXPECT_TRUE(str_util::EndsWith(a, e));
+  EXPECT_TRUE(str_util::EndsWith(b, s1));
+  EXPECT_TRUE(str_util::EndsWith(b, b));
+  EXPECT_TRUE(str_util::EndsWith(b, e));
+  EXPECT_TRUE(str_util::EndsWith(e, ""));
+  EXPECT_FALSE(str_util::EndsWith(a, b));
+  EXPECT_FALSE(str_util::EndsWith(b, a));
+  EXPECT_FALSE(str_util::EndsWith(e, a));
+}
+
+TEST(StrContains, Basic) {
+  StringPiece a("abcdefg");
+  StringPiece b("abcd");
+  StringPiece c("efg");
+  StringPiece d("gh");
+  EXPECT_TRUE(str_util::StrContains(a, b));
+  EXPECT_TRUE(str_util::StrContains(a, c));
+  EXPECT_TRUE(!str_util::StrContains(a, d));
+}
+
 }  // namespace tensorflow