replace boost filesystem with std filesystem; upgrade gtest and find it using cmake.

webcc/string.cc

@@ -0,0 +1,40 @@
+#include "webcc/string.h"
+
+#include <random>
+
+namespace webcc {
+namespace string {
+
+// See: https://stackoverflow.com/a/24586587
+std::string RandomString(std::size_t length) {
+  static const char chrs[] =
+      "0123456789"
+      "abcdefghijklmnopqrstuvwxyz"
+      "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+  thread_local static std::mt19937 rg{ std::random_device{}() };
+  thread_local static std::uniform_int_distribution<std::string::size_type>
+      pick(0, sizeof(chrs) - 2);
+
+  std::string s;
+  s.reserve(length);
+
+  while (length--) {
+    s += chrs[pick(rg)];
+  }
+
+  return s;
+}
+
+bool EqualsNoCase(const std::string& str1, const std::string& str2) {
+  if (str1.size() != str2.size()) {
+    return false;
+  }
+
+  return std::equal(str1.begin(), str1.end(), str2.begin(), [](int c1, int c2) {
+    return std::toupper(c1) == std::toupper(c2);
+  });
+}
+
+}  // namespace string
+}  // namespace webcc