Include RE2 library

third_party/re2/re2/testing/string_generator_test.cc

+// Copyright 2008 The RE2 Authors.  All Rights Reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Test StringGenerator.
+
+#include <stdlib.h>
+#include <string>
+#include <vector>
+#include "util/test.h"
+#include "re2/testing/string_generator.h"
+#include "re2/testing/regexp_generator.h"
+
+namespace re2 {
+
+// Returns i to the e.
+static int64 IntegerPower(int i, int e) {
+  int64 p = 1;
+  while (e-- > 0)
+    p *= i;
+  return p;
+}
+
+// Checks that for given settings of the string generator:
+//   * it generates strings that are non-decreasing in length.
+//   * strings of the same length are sorted in alphabet order.
+//   * it doesn't generate the same string twice.
+//   * it generates the right number of strings.
+//
+// If all of these hold, the StringGenerator is behaving.
+// Assumes that the alphabet is sorted, so that the generated
+// strings can just be compared lexicographically.
+static void RunTest(int len, string alphabet, bool donull) {
+  StringGenerator g(len, Explode(alphabet));
+
+  int n = 0;
+  int last_l = -1;
+  string last_s;
+
+  if (donull) {
+    g.GenerateNULL();
+    EXPECT_TRUE(g.HasNext());
+    StringPiece sp = g.Next();
+    EXPECT_EQ(sp.data(), static_cast<const char*>(NULL));
+    EXPECT_EQ(sp.size(), 0);
+  }
+
+  while (g.HasNext()) {
+    string s = g.Next().as_string();
+    n++;
+
+    // Check that all characters in s appear in alphabet.
+    for (const char *p = s.c_str(); *p != '\0'; ) {
+      Rune r;
+      p += chartorune(&r, p);
+      EXPECT_TRUE(utfrune(alphabet.c_str(), r) != NULL);
+    }
+
+    // Check that string is properly ordered w.r.t. previous string.
+    int l = utflen(s.c_str());
+    EXPECT_LE(l, len);
+    if (last_l < l) {
+      last_l = l;
+    } else {
+      EXPECT_EQ(last_l, l);
+      EXPECT_LT(last_s, s);
+    }
+    last_s = s;
+  }
+
+  // Check total string count.
+  int64 m = 0;
+  int alpha = utflen(alphabet.c_str());
+  if (alpha == 0)  // Degenerate case.
+    len = 0;
+  for (int i = 0; i <= len; i++)
+    m += IntegerPower(alpha, i);
+  EXPECT_EQ(n, m);
+}
+
+TEST(StringGenerator, NoLength) {
+  RunTest(0, "abc", false);
+}
+
+TEST(StringGenerator, NoLengthNoAlphabet) {
+  RunTest(0, "", false);
+}
+
+TEST(StringGenerator, NoAlphabet) {
+  RunTest(5, "", false);
+}
+
+TEST(StringGenerator, Simple) {
+  RunTest(3, "abc", false);
+}
+
+TEST(StringGenerator, UTF8) {
+  RunTest(4, "abc\xE2\x98\xBA", false);
+}
+
+TEST(StringGenerator, GenNULL) {
+  RunTest(0, "abc", true);
+  RunTest(0, "", true);
+  RunTest(5, "", true);
+  RunTest(3, "abc", true);
+  RunTest(4, "abc\xE2\x98\xBA", true);
+}
+
+}  // namespace re2