Replace uses of RE2 with Scanner, for sources that are used on mobile.

This CL also adds the Scanner class to do simple scans over strings, to mimic
regexp behavior like [a-zA-Z][a-zA-Z0-9]* with:

 Scanner scan(s);
 scan.One(Scanner::LETTER);
 scan.Any(Scanner::LETTER_DIGIT);
 bool matched = scan.GetResult();
Change: 116803757

1 files changed, 266 insertions, 0 deletions

diff --git a/tensorflow/core/lib/strings/scanner_test.cc b/tensorflow/core/lib/strings/scanner_test.cc
new file mode 100644
index 0000000000..98028ae516
--- /dev/null
+++ b/tensorflow/core/lib/strings/scanner_test.cc
@@ -0,0 +1,266 @@
+/* Copyright 2016 Google Inc. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+
+#include "tensorflow/core/lib/strings/scanner.h"
+
+#include "tensorflow/core/platform/test.h"
+
+namespace tensorflow {
+namespace strings {
+
+class ScannerTest : public ::testing::Test {
+ protected:
+  // Returns a string with all chars that are in <clz>, in byte value order.
+  string ClassStr(Scanner::CharClass clz) {
+    string s;
+    for (int i = 0; i < 256; ++i) {
+      char ch = i;
+      if (Scanner::Matches(clz, ch)) {
+        s += ch;
+      }
+    }
+    return s;
+  }
+};
+
+TEST_F(ScannerTest, Any) {
+  StringPiece remaining, match;
+  EXPECT_TRUE(Scanner("   horse0123")
+                  .Any(Scanner::SPACE)
+                  .Any(Scanner::DIGIT)
+                  .Any(Scanner::LETTER)
+                  .GetResult(&remaining, &match));
+  EXPECT_EQ("   horse", match.ToString());
+  EXPECT_EQ("0123", remaining.ToString());
+
+  EXPECT_TRUE(Scanner("")
+                  .Any(Scanner::SPACE)
+                  .Any(Scanner::DIGIT)
+                  .Any(Scanner::LETTER)
+                  .GetResult(&remaining, &match));
+  EXPECT_EQ("", remaining.ToString());
+  EXPECT_EQ("", match.ToString());
+
+  EXPECT_TRUE(Scanner("----")
+                  .Any(Scanner::SPACE)
+                  .Any(Scanner::DIGIT)
+                  .Any(Scanner::LETTER)
+                  .GetResult(&remaining, &match));
+  EXPECT_EQ("----", remaining.ToString());
+  EXPECT_EQ("", match.ToString());
+}
+
+TEST_F(ScannerTest, AnySpace) {
+  StringPiece remaining, match;
+  EXPECT_TRUE(Scanner("  a b ")
+                  .AnySpace()
+                  .One(Scanner::LETTER)
+                  .AnySpace()
+                  .GetResult(&remaining, &match));
+  EXPECT_EQ("  a ", match.ToString());
+  EXPECT_EQ("b ", remaining.ToString());
+}
+
+TEST_F(ScannerTest, Eos) {
+  EXPECT_FALSE(Scanner("a").Eos().GetResult());
+  EXPECT_TRUE(Scanner("").Eos().GetResult());
+  EXPECT_FALSE(Scanner("abc").OneLiteral("ab").Eos().GetResult());
+  EXPECT_TRUE(Scanner("abc").OneLiteral("abc").Eos().GetResult());
+}
+
+TEST_F(ScannerTest, Many) {
+  StringPiece remaining, match;
+  EXPECT_TRUE(Scanner("abc").Many(Scanner::LETTER).GetResult());
+  EXPECT_FALSE(Scanner("0").Many(Scanner::LETTER).GetResult());
+  EXPECT_FALSE(Scanner("").Many(Scanner::LETTER).GetResult());
+
+  EXPECT_TRUE(
+      Scanner("abc ").Many(Scanner::LETTER).GetResult(&remaining, &match));
+  EXPECT_EQ(" ", remaining);
+  EXPECT_EQ("abc", match);
+  EXPECT_TRUE(
+      Scanner("abc").Many(Scanner::LETTER).GetResult(&remaining, &match));
+  EXPECT_EQ("", remaining);
+  EXPECT_EQ("abc", match);
+}
+
+TEST_F(ScannerTest, One) {
+  StringPiece remaining, match;
+  EXPECT_TRUE(Scanner("abc").One(Scanner::LETTER).GetResult());
+  EXPECT_FALSE(Scanner("0").One(Scanner::LETTER).GetResult());
+  EXPECT_FALSE(Scanner("").One(Scanner::LETTER).GetResult());
+
+  EXPECT_TRUE(Scanner("abc")
+                  .One(Scanner::LETTER)
+                  .One(Scanner::LETTER)
+                  .GetResult(&remaining, &match));
+  EXPECT_EQ("c", remaining);
+  EXPECT_EQ("ab", match);
+  EXPECT_TRUE(Scanner("a").One(Scanner::LETTER).GetResult(&remaining, &match));
+  EXPECT_EQ("", remaining);
+  EXPECT_EQ("a", match);
+}
+
+TEST_F(ScannerTest, OneLiteral) {
+  EXPECT_FALSE(Scanner("abc").OneLiteral("abC").GetResult());
+  EXPECT_TRUE(Scanner("abc").OneLiteral("ab").OneLiteral("c").GetResult());
+}
+
+TEST_F(ScannerTest, ScanEscapedUntil) {
+  StringPiece remaining, match;
+  EXPECT_TRUE(Scanner(R"(' \1 \2 \3 \' \\'rest)")
+                  .OneLiteral("'")
+                  .ScanEscapedUntil('\'')
+                  .OneLiteral("'")
+                  .GetResult(&remaining, &match));
+  EXPECT_EQ("rest", remaining.ToString());
+  EXPECT_EQ(R"(' \1 \2 \3 \' \\')", match.ToString());
+
+  // The "scan until" character is not present.
+  remaining = match = "unset";
+  EXPECT_FALSE(Scanner(R"(' \1 \2 \3 \' \\rest)")
+                   .OneLiteral("'")
+                   .ScanEscapedUntil('\'')
+                   .GetResult(&remaining, &match));
+  EXPECT_EQ("unset", remaining.ToString());
+  EXPECT_EQ("unset", match.ToString());
+}
+
+TEST_F(ScannerTest, ZeroOrOneLiteral) {
+  StringPiece remaining, match;
+  EXPECT_TRUE(
+      Scanner("abc").ZeroOrOneLiteral("abC").GetResult(&remaining, &match));
+  EXPECT_EQ("abc", remaining.ToString());
+  EXPECT_EQ("", match.ToString());
+
+  EXPECT_TRUE(
+      Scanner("abcd").ZeroOrOneLiteral("ab").ZeroOrOneLiteral("c").GetResult(
+          &remaining, &match));
+  EXPECT_EQ("d", remaining.ToString());
+  EXPECT_EQ("abc", match.ToString());
+
+  EXPECT_TRUE(
+      Scanner("").ZeroOrOneLiteral("abc").GetResult(&remaining, &match));
+  EXPECT_EQ("", remaining.ToString());
+  EXPECT_EQ("", match.ToString());
+}
+
+// Test output of GetResult (including the forms with optional params),
+// and that it can be called multiple times.
+TEST_F(ScannerTest, CaptureAndGetResult) {
+  StringPiece remaining, match;
+
+  Scanner scan("  first    second");
+  EXPECT_TRUE(scan.Any(Scanner::SPACE)
+                  .RestartCapture()
+                  .One(Scanner::LETTER)
+                  .Any(Scanner::LETTER_DIGIT)
+                  .StopCapture()
+                  .Any(Scanner::SPACE)
+                  .GetResult(&remaining, &match));
+  EXPECT_EQ("second", remaining.ToString());
+  EXPECT_EQ("first", match.ToString());
+  EXPECT_TRUE(scan.GetResult());
+  remaining = "";
+  EXPECT_TRUE(scan.GetResult(&remaining));
+  EXPECT_EQ("second", remaining.ToString());
+  remaining = "";
+  match = "";
+  EXPECT_TRUE(scan.GetResult(&remaining, &match));
+  EXPECT_EQ("second", remaining.ToString());
+  EXPECT_EQ("first", match.ToString());
+}
+
+// Tests that if StopCapture is not called, then calling GetResult, then
+// scanning more, then GetResult again will update the capture.
+TEST_F(ScannerTest, MultipleGetResultExtendsCapture) {
+  StringPiece remaining, match;
+
+  Scanner scan("one2three");
+  EXPECT_TRUE(scan.Many(Scanner::LETTER).GetResult(&remaining, &match));
+  EXPECT_EQ("2three", remaining.ToString());
+  EXPECT_EQ("one", match.ToString());
+  EXPECT_TRUE(scan.Many(Scanner::DIGIT).GetResult(&remaining, &match));
+  EXPECT_EQ("three", remaining.ToString());
+  EXPECT_EQ("one2", match.ToString());
+  EXPECT_TRUE(scan.Many(Scanner::LETTER).GetResult(&remaining, &match));
+  EXPECT_EQ("", remaining.ToString());
+  EXPECT_EQ("one2three", match.ToString());
+}
+
+TEST_F(ScannerTest, FailedMatchDoesntChangeResult) {
+  // A failed match doesn't change pointers passed to GetResult.
+  Scanner scan("name");
+  StringPiece remaining = "rem";
+  StringPiece match = "match";
+  EXPECT_FALSE(scan.One(Scanner::SPACE).GetResult(&remaining, &match));
+  EXPECT_EQ("rem", remaining.ToString());
+  EXPECT_EQ("match", match.ToString());
+}
+
+TEST_F(ScannerTest, DefaultCapturesAll) {
+  // If RestartCapture() is not called, the whole string is used.
+  Scanner scan("a b");
+  StringPiece remaining = "rem";
+  StringPiece match = "match";
+  EXPECT_TRUE(scan.Any(Scanner::LETTER)
+                  .AnySpace()
+                  .Any(Scanner::LETTER)
+                  .GetResult(&remaining, &match));
+  EXPECT_EQ("", remaining.ToString());
+  EXPECT_EQ("a b", match.ToString());
+}
+
+TEST_F(ScannerTest, AllCharClasses) {
+  EXPECT_EQ("0123456789", ClassStr(Scanner::DIGIT));
+  EXPECT_EQ("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
+            ClassStr(Scanner::LETTER));
+  EXPECT_EQ("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
+            ClassStr(Scanner::LETTER_DIGIT));
+  EXPECT_EQ(
+      "-./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+      "abcdefghijklmnopqrstuvwxyz",
+      ClassStr(Scanner::LETTER_DIGIT_DASH_DOT_SLASH));
+  EXPECT_EQ(
+      "-./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_"
+      "abcdefghijklmnopqrstuvwxyz",
+      ClassStr(Scanner::LETTER_DIGIT_DASH_DOT_SLASH_UNDERSCORE));
+  EXPECT_EQ(".0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz",
+            ClassStr(Scanner::LETTER_DIGIT_DOT));
+  EXPECT_EQ(".0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz",
+            ClassStr(Scanner::LETTER_DIGIT_DOT_UNDERSCORE));
+  EXPECT_EQ("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ_abcdefghijklmnopqrstuvwxyz",
+            ClassStr(Scanner::LETTER_DIGIT_UNDERSCORE));
+  EXPECT_EQ("abcdefghijklmnopqrstuvwxyz", ClassStr(Scanner::LOWERLETTER));
+  EXPECT_EQ("0123456789abcdefghijklmnopqrstuvwxyz",
+            ClassStr(Scanner::LOWERLETTER_DIGIT));
+  EXPECT_EQ("0123456789_abcdefghijklmnopqrstuvwxyz",
+            ClassStr(Scanner::LOWERLETTER_DIGIT_UNDERSCORE));
+  EXPECT_EQ("123456789", ClassStr(Scanner::NON_ZERO_DIGIT));
+  EXPECT_EQ("\t\n\v\f\r ", ClassStr(Scanner::SPACE));
+  EXPECT_EQ("ABCDEFGHIJKLMNOPQRSTUVWXYZ", ClassStr(Scanner::UPPERLETTER));
+}
+
+TEST_F(ScannerTest, Peek) {
+  EXPECT_EQ('a', Scanner("abc").Peek());
+  EXPECT_EQ('a', Scanner("abc").Peek('b'));
+  EXPECT_EQ('\0', Scanner("").Peek());
+  EXPECT_EQ('z', Scanner("").Peek('z'));
+  EXPECT_EQ('A', Scanner("0123A").Any(Scanner::DIGIT).Peek());
+  EXPECT_EQ('\0', Scanner("0123A").Any(Scanner::LETTER_DIGIT).Peek());
+}
+
+}  // namespace strings
+}  // namespace tensorflow