diff --git a/oss-internship-2020/libtiff/CMakeLists.txt b/oss-internship-2020/libtiff/CMakeLists.txt
index b659fd3..59175d1 100644
--- a/oss-internship-2020/libtiff/CMakeLists.txt
+++ b/oss-internship-2020/libtiff/CMakeLists.txt
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-cmake_minimum_required(VERSION 3.10)
+cmake_minimum_required(VERSION 3.12)
 
 project(sandboxed_libtiff CXX)
 
@@ -120,10 +120,10 @@ target_include_directories(tiff_sapi INTERFACE
     "${PROJECT_BINARY_DIR}"  # To find the generated SAPI header
 )
 
-if (TIFF_SAPI_ENABLE_EXAMPLES)
+#if (TIFF_SAPI_ENABLE_EXAMPLES)
   add_subdirectory(example)
-endif()
+#endif()
 
-if (TIFF_SAPI_ENABLE_TESTS)
+#if (TIFF_SAPI_ENABLE_TESTS)
   add_subdirectory(test)
-endif()
+#endif()
diff --git a/oss-internship-2020/libtiff/README.md b/oss-internship-2020/libtiff/README.md
index 4e253db..75ba011 100644
--- a/oss-internship-2020/libtiff/README.md
+++ b/oss-internship-2020/libtiff/README.md
@@ -19,4 +19,4 @@ You should make sure the libtiff submodule is cloned.
 #### to run tests:
 `./test/tests`
 
-you also can use sandbox flags `sandbox2_danger_danger_permit_all` and `sandbox2_danger_danger_permit_all_and_log`
+You also can use sandbox flags `sandbox2_danger_danger_permit_all` and `sandbox2_danger_danger_permit_all_and_log`.
diff --git a/oss-internship-2020/libtiff/example/main_sandboxed.cc b/oss-internship-2020/libtiff/example/main_sandboxed.cc
index 5b61acd..fe59e8b 100644
--- a/oss-internship-2020/libtiff/example/main_sandboxed.cc
+++ b/oss-internship-2020/libtiff/example/main_sandboxed.cc
@@ -12,36 +12,39 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <cstdlib>
 #include <cstring>
 #include <iostream>
-#include <vector>
+#include <array>
+#include <cstdint>
 
 #include "../sandboxed.h"
 #include "sandboxed_api/sandbox2/util/fileops.h"
 #include "sandboxed_api/sandbox2/util/path.h"
-#include "tiffio.h"
+#include "sandboxed_api/vars.h"
+#include "tiffio.h"  // NOLINT(build/include)
 
-/* sapi functions:
- *    TIFFTileSize
- *    TIFFOpen
- *    TIFFReadEncodedTile
- *    TIFFSetField
- *    TIFFClose
- *    TIFFReadRGBATile
- *    TIFFGetField
- */
+// sapi functions:
+//  TIFFTileSize
+//  TIFFOpen
+//  TIFFReadEncodedTile
+//  TIFFSetField
+//  TIFFClose
+//  TIFFReadRGBATile
+//  TIFFGetField
 
-static const std::vector<unsigned char> cluster_0 = {0, 0, 2, 0, 138, 139};
-static const std::vector<unsigned char> cluster_64 = {0, 0, 9, 6, 134, 119};
-static const std::vector<unsigned char> cluster_128 = {44, 40, 63, 59, 230, 95};
+constexpr std::array<uint8_t, 6> kCluster0 = {0, 0, 2, 0, 138, 139};
+constexpr std::array<uint8_t, 6> kCluster64 = {0, 0, 9, 6, 134, 119};
+constexpr std::array<uint8_t, 6> kCluster128 = {44, 40, 63, 59, 230, 95};
 
-static int CheckCluster(int cluster,
-                        const sapi::v::Array<unsigned char> &buffer,
-                        const std::vector<unsigned char> &expected_cluster) {
-  unsigned char* target = buffer.GetData() + cluster * 6;
+namespace {
+
+absl::Status CheckCluster(int cluster, const sapi::v::Array<uint8_t>& buffer,
+                          const std::array<uint8_t, 6>& expected_cluster) {
+  uint8_t* target = buffer.GetData() + cluster * 6;
 
   if (!std::memcmp(target, expected_cluster.data(), 6)) {
-    return 0;
+    return absl::OkStatus();
   }
 
   std::cerr << "Cluster " << cluster << " did not match expected results.\n"
@@ -53,31 +56,36 @@ static int CheckCluster(int cluster,
             << "\t" << target[5] << "\t" << target[2] << "\t" << target[3]
             << '\n';
 
-  return 1;
+  return absl::InternalError(absl::StrCat(
+    "Cluster ", cluster, " did not match expected results.\n", "Expect: ",
+    expected_cluster[0], "\t", expected_cluster[1], "\t", expected_cluster[4],
+    "\t", expected_cluster[5], "\t", expected_cluster[2], "\t",
+    expected_cluster[3], "\n"
+  ));
 }
 
-static int CheckRgbPixel(int pixel, int min_red, int max_red, int min_green,
-                         int max_green, int min_blue, int max_blue,
-                         const sapi::v::Array<unsigned char> &buffer) {
-  unsigned char* rgb = buffer.GetData() + 3 * pixel;
+absl::Status CheckRgbPixel(int pixel, int min_red, int max_red, int min_green,
+                           int max_green, int min_blue, int max_blue,
+                           const sapi::v::Array<uint8_t>& buffer) {
+  uint8_t* rgb = buffer.GetData() + 3 * pixel;
 
   if (rgb[0] >= min_red && rgb[0] <= max_red && rgb[1] >= min_green &&
       rgb[1] <= max_green && rgb[2] >= min_blue && rgb[2] <= max_blue) {
-    return 0;
+    return absl::OkStatus();
   }
 
-  std::cerr << "Pixel " << pixel << " did not match expected results.\n"
-            << "Got R=" << rgb[0] << " (expected " << min_red << ".." << max_red
-            << "), G=" << rgb[1] << " (expected " << min_green << ".."
-            << max_green << "), B=" << rgb[2] << " (expected " << min_blue
-            << ".." << max_blue << ")\n";
-  return 1;
+  return absl::InternalError(absl::StrCat(
+    "Pixel ", pixel, " did not match expected results.\n", "Got R=", rgb[0],
+    " (expected ", min_red, "..", max_red, "), G=", rgb[1], " (expected ",
+    min_green, "..", max_green, "), B=", rgb[2], " (expected ", min_blue, "..",
+    max_blue, ")\n"
+  ));
 }
 
-static int CheckRgbaPixel(int pixel, int min_red, int max_red, int min_green,
-                          int max_green, int min_blue, int max_blue,
-                          int min_alpha, int max_alpha,
-                          const sapi::v::Array<unsigned> &buffer) {
+absl::Status CheckRgbaPixel(int pixel, int min_red, int max_red, int min_green,
+                            int max_green, int min_blue, int max_blue,
+                            int min_alpha, int max_alpha,
+                            const sapi::v::Array<unsigned>& buffer) {
   // RGBA images are upside down - adjust for normal ordering
   int adjusted_pixel = pixel % 128 + (127 - (pixel / 128)) * 128;
   uint32 rgba = buffer[adjusted_pixel];
@@ -89,37 +97,33 @@ static int CheckRgbaPixel(int pixel, int min_red, int max_red, int min_green,
       TIFFGetB(rgba) <= (uint32)max_blue &&
       TIFFGetA(rgba) >= (uint32)min_alpha &&
       TIFFGetA(rgba) <= (uint32)max_alpha) {
-    return 0;
+    return absl::OkStatus();
   }
 
-  std::cerr << "Pixel " << pixel << " did not match expected results.\n"
-            << "Got R=" << TIFFGetR(rgba) << " (expected " << min_red << ".."
-            << max_red << "), G=" << TIFFGetG(rgba) << " (expected "
-            << min_green << ".." << max_green << "), B=" << TIFFGetB(rgba)
-            << " (expected " << min_blue << ".." << max_blue
-            << "), A=" << TIFFGetA(rgba) << " (expected " << min_alpha << ".."
-            << max_alpha << ")\n";
-  return 1;
+  return absl::InternalError(absl::StrCat(
+    "Pixel ", pixel, " did not match expected results.\n", "Got R=",
+    TIFFGetR(rgba), " (expected ", min_red, "..", max_red, "), G=",
+    TIFFGetG(rgba), " (expected ", min_green, "..", max_green, "), B=",
+    TIFFGetB(rgba), " (expected ", min_blue, "..", max_blue, "), A=",
+    TIFFGetA(rgba), " (expected ", min_alpha, "..", max_alpha, ")\n"
+  ));
 }
-std::string GetFilePath(const std::string &dir, const std::string &filename) {
+
+} // namespace
+
+std::string GetFilePath(const std::string& dir, const std::string& filename) {
   return sandbox2::file::JoinPath(dir, "test", "images", filename);
 }
 
-std::string GetCWD() {
-  char cwd[PATH_MAX];
-  getcwd(cwd, sizeof(cwd));
-  return cwd;
-}
-
 std::string GetFilePath(const std::string filename) {
-  std::string cwd = GetCWD();
+  std::string cwd = sandbox2::file_util::fileops::GetCWD();
   auto find = cwd.rfind("build");
 
   std::string project_path;
   if (find == std::string::npos) {
-    std::cerr << "Something went wrong: CWD don't contain build dir. "
-              << "Please run tests from build dir or send project dir as a "
-              << "parameter: ./sandboxed /absolute/path/to/project/dir \n";
+    LOG(ERROR) << "Something went wrong: CWD don't contain build dir. "
+               << "Please run tests from build dir or send project dir as a "
+               << "parameter: ./sandboxed /absolute/path/to/project/dir \n";
     project_path = cwd;
   } else {
     project_path = cwd.substr(0, find);
@@ -128,6 +132,173 @@ std::string GetFilePath(const std::string filename) {
   return sandbox2::file::JoinPath(project_path, "test", "images", filename);
 }
 
+absl::Status LibTIFFMain(const std::string& srcfile) {
+  // without addDir to sandbox. to add dir use
+  // sandbox(absolute_path_to_dir, srcfile) or
+  // sandbox(absolute_path_to_dir). file and dir should be exists.
+  // srcfile must also be absolute_path_to_file
+  TiffSapiSandbox sandbox("", srcfile);
+
+  // initialize sapi vars after constructing TiffSapiSandbox
+  sapi::v::UShort h, v;
+  sapi::StatusOr<TIFF*> status_or_tif;
+  sapi::StatusOr<int> status_or_int;
+  sapi::StatusOr<tmsize_t> status_or_long;
+  absl::Status status;
+
+  status = sandbox.Init();
+
+  SAPI_RETURN_IF_ERROR(sandbox.Init());
+
+  TiffApi api(&sandbox);
+  sapi::v::ConstCStr srcfile_var(srcfile.c_str());
+  sapi::v::ConstCStr r_var("r");
+
+  SAPI_ASSIGN_OR_RETURN(
+    status_or_tif, api.TIFFOpen(srcfile_var.PtrBefore(), r_var.PtrBefore()));
+
+  sapi::v::RemotePtr tif(status_or_tif.value());
+  if (!tif.GetValue()) {
+    // tif is NULL
+    return absl::InternalError(absl::StrCat("Could not open ", srcfile));
+  }
+
+  SAPI_ASSIGN_OR_RETURN(
+    status_or_int, api.TIFFGetField2(&tif, TIFFTAG_YCBCRSUBSAMPLING,
+                                     h.PtrBoth(), v.PtrBoth()));
+  if (status_or_int.value() == 0 || h.GetValue() != 2 || v.GetValue() != 2) {
+    return absl::InternalError("Could not retrieve subsampling tag");
+  }
+
+  SAPI_ASSIGN_OR_RETURN(
+    status_or_long, api.TIFFTileSize(&tif));
+  if (status_or_long.value() != 24576) {
+    return absl::InternalError(absl::StrCat("tiles are ",
+                                            status_or_long.value(),
+                                            " bytes\n"));
+  }
+  tsize_t sz = status_or_long.value();
+
+  sapi::v::Array<uint8_t> buffer_(sz);
+  SAPI_ASSIGN_OR_RETURN(
+    status_or_long, api.TIFFReadEncodedTile(&tif, 9, buffer_.PtrBoth(), sz));
+  if (status_or_long.value() != sz) {
+    return absl::InternalError(absl::StrCat(
+      "Did not get expected result code from TIFFReadEncodedTile(): ",
+      status_or_long.value(), " instead of ", sz
+    ));
+  }
+
+  unsigned pixel_status = 1;
+  if (status = CheckCluster(0, buffer_, kCluster0); !status.ok()) {
+    LOG(ERROR) << "CheckCluster failed:\n" << status.ToString();
+  }
+  pixel_status &= status.ok();
+
+  if (status = CheckCluster(64, buffer_, kCluster64); !status.ok()) {
+    LOG(ERROR) << "CheckCluster failed:\n" << status.ToString();
+  }
+  pixel_status &= status.ok();
+  
+  if (status = CheckCluster(128, buffer_, kCluster128); !status.ok()) {
+    LOG(ERROR) << "CheckCluster failed:\n" << status.ToString();
+  }
+  pixel_status &= status.ok();
+
+  if (!pixel_status) {
+    return absl::InternalError("unexpected pixel_status value");
+  }
+
+  SAPI_ASSIGN_OR_RETURN(
+    status_or_int, api.TIFFSetFieldU1(&tif, TIFFTAG_JPEGCOLORMODE,
+                                      JPEGCOLORMODE_RGB));
+  if (!status_or_int.value()) {
+    return absl::InternalError("TIFFSetFieldU1 not available");
+  }
+
+  SAPI_ASSIGN_OR_RETURN(
+    status_or_long, api.TIFFTileSize(&tif));
+  if (status_or_long.value() != 128 * 128 * 3) {
+    return absl::InternalError(absl::StrCat("tiles are ",
+                                            status_or_long.value(),
+                                            " bytes"));
+  }
+  sz = status_or_long.value();
+
+  sapi::v::Array<uint8_t> buffer2_(sz);
+
+  SAPI_ASSIGN_OR_RETURN(
+    status_or_long, api.TIFFReadEncodedTile(&tif, 9, buffer2_.PtrBoth(), sz));
+  if (status_or_long.value() != sz) {
+    return absl::InternalError(absl::StrCat(
+      "Did not get expected result code from TIFFReadEncodedTile(): ",
+      status_or_long.value(), " instead of ", sz
+    ));
+  }
+
+  pixel_status = 1;
+  if (status = CheckRgbPixel(0, 15, 18, 0, 0, 18, 41, buffer2_);
+      !status.ok()) {
+    LOG(ERROR) << "CheckRgbPixel failed:\n" << status.ToString();
+  }
+  pixel_status &= status.ok();
+
+  if (status = CheckRgbPixel(64, 0, 0, 0, 0, 0, 2, buffer2_); !status.ok()) {
+    LOG(ERROR) << "CheckRgbPixel failed:\n" << status.ToString();
+  }
+  pixel_status &= status.ok();
+  
+  if (status = CheckRgbPixel(512, 5, 6, 34, 36, 182, 196, buffer2_);
+      !status.ok()) {
+    LOG(ERROR) << "CheckRgbPixel failed:\n" << status.ToString();
+  }
+  pixel_status &= status.ok();
+
+  SAPI_RETURN_IF_ERROR(api.TIFFClose(&tif));
+
+  SAPI_ASSIGN_OR_RETURN(
+    status_or_tif, api.TIFFOpen(srcfile_var.PtrBefore(), r_var.PtrBefore()));
+
+  sapi::v::RemotePtr tif2(status_or_tif.value());
+  if (!tif2.GetValue()) {  // tif is NULL
+    return absl::InternalError(absl::StrCat("Could not reopen ", srcfile));
+  }
+
+  sapi::v::Array<uint32> rgba_buffer_(128 * 128);
+
+  SAPI_ASSIGN_OR_RETURN(status_or_int,
+    api.TIFFReadRGBATile(&tif2, 1 * 128, 2 * 128, rgba_buffer_.PtrBoth()));
+  if (!status_or_int.value()) {
+    return absl::InternalError("TIFFReadRGBATile() returned failure code");
+  }
+
+  if (status = CheckRgbaPixel(0, 15, 18, 0, 0, 18, 41, 255, 255, rgba_buffer_);
+      !status.ok()) {
+    LOG(ERROR) << "CheckRgbaPixel failed:\n" << status.ToString();
+  }
+  pixel_status &= status.ok();
+
+  if (status = CheckRgbaPixel(64, 0, 0, 0, 0, 0, 2, 255, 255, rgba_buffer_);
+      !status.ok()) {
+    LOG(ERROR) << "CheckRgbaPixel failed:\n" << status.ToString();
+  }
+  pixel_status &= status.ok();
+  
+  if (status = CheckRgbaPixel(512, 5, 6, 34, 36, 182, 196, 255, 255,
+                              rgba_buffer_); !status.ok()) {
+    LOG(ERROR) << "CheckRgbaPixel failed:\n" << status.ToString();
+  }
+  pixel_status &= status.ok();
+
+  SAPI_RETURN_IF_ERROR(api.TIFFClose(&tif2));
+
+  if (!pixel_status) {
+    return absl::InternalError("unexpected pixel_status value");
+  }
+
+  return absl::OkStatus();
+}
+
 int main(int argc, char** argv) {
   gflags::ParseCommandLineFlags(&argc, &argv, true);
 
@@ -141,137 +312,12 @@ int main(int argc, char** argv) {
     srcfile = GetFilePath(argv[1], srcfilerel);
   }
 
-  // without addDir to sandbox. to add dir use
-  // sandbox(absolute_path_to_dir, srcfile) or
-  // sandbox(absolute_path_to_dir). file and dir should be exists.
-  // srcfile must also be absolute_path_to_file
-  TiffSapiSandbox sandbox("", srcfile);
-
-  // initialize sapi vars after constructing TiffSapiSandbox
-  sapi::v::UShort h, v;
-  sapi::StatusOr<TIFF*> status_or_tif;
-  sapi::StatusOr<int> status_or_int;
-  sapi::StatusOr<tmsize_t> status_or_long;
-
-  auto status = sandbox.Init();
+  auto status = LibTIFFMain(srcfile);
   if (!status.ok()) {
-    fprintf(stderr, "Couldn't initialize Sandboxed API: %s\n", status);
+    LOG(ERROR)
+      << "LibTIFFMain failed with error:\n" << status.ToString() << '\n';
+    return EXIT_FAILURE;
   }
 
-  TiffApi api(&sandbox);
-  sapi::v::ConstCStr srcfile_var(srcfile.c_str());
-  sapi::v::ConstCStr r_var("r");
-
-  status_or_tif = api.TIFFOpen(srcfile_var.PtrBefore(), r_var.PtrBefore());
-  if (!status_or_tif.ok()) {
-    std::cerr << "Could not open " << srcfile << ", TIFFError\n";
-    return 1;
-  }
-
-  sapi::v::RemotePtr tif(status_or_tif.value());
-  if (!tif.GetValue()) {
-    // tif is NULL
-    std::cerr << "Could not open " << srcfile << "\n";
-    return 1;
-  }
-
-  status_or_int = api.TIFFGetField2(&tif, TIFFTAG_YCBCRSUBSAMPLING, h.PtrBoth(),
-                                    v.PtrBoth());
-  if (!status_or_int.ok() || status_or_int.value() == 0 || h.GetValue() != 2 ||
-      v.GetValue() != 2) {
-    std::cerr << "Could not retrieve subsampling tag\n";
-    return 1;
-  }
-
-  status_or_long = api.TIFFTileSize(&tif);
-  if (!status_or_int.ok() || status_or_long.value() != 24576) {
-    std::cerr << "tiles are " << status_or_long.value() << " bytes\n";
-    exit(1);
-  }
-  tsize_t sz = status_or_long.value();
-
-  sapi::v::Array<unsigned char> buffer_(sz);
-  status_or_long = api.TIFFReadEncodedTile(&tif, 9, buffer_.PtrBoth(), sz);
-  if (!status_or_long.ok() || status_or_long.value() != sz) {
-    std::cerr << "Did not get expected result code from"
-              << "TIFFReadEncodedTile(): (" << status_or_long.value()
-              << " instead of " << sz << ")\n";
-    return 1;
-  }
-
-  if (CheckCluster(0, buffer_, cluster_0) ||
-      CheckCluster(64, buffer_, cluster_64) ||
-      CheckCluster(128, buffer_, cluster_128)) {
-    return 1;
-  }
-
-  status_or_int =
-      api.TIFFSetFieldU1(&tif, TIFFTAG_JPEGCOLORMODE, JPEGCOLORMODE_RGB);
-  if (!status_or_int.ok() || !status_or_int.value()) {
-    std::cerr << "TIFFSetFieldU1 not available\n";
-  }
-
-  status_or_long = api.TIFFTileSize(&tif);
-  if (!status_or_long.ok() || status_or_long.value() != 128 * 128 * 3) {
-    std::cerr << "tiles are " << status_or_long.value() << " bytes\n";
-    return 1;
-  }
-  sz = status_or_long.value();
-
-  sapi::v::Array<unsigned char> buffer2_(sz);
-
-  status_or_long = api.TIFFReadEncodedTile(&tif, 9, buffer2_.PtrBoth(), sz);
-  if (!status_or_long.ok() || status_or_long.value() != sz) {
-    std::cerr << "Did not get expected result code from "
-              << "TIFFReadEncodedTile(): (" << status_or_long.value()
-              << " instead of " << sz << ")\n";
-    return 1;
-  }
-
-  unsigned pixel_status = 0;
-  pixel_status |= CheckRgbPixel(0, 15, 18, 0, 0, 18, 41, buffer2_);
-  pixel_status |= CheckRgbPixel(64, 0, 0, 0, 0, 0, 2, buffer2_);
-  pixel_status |= CheckRgbPixel(512, 5, 6, 34, 36, 182, 196, buffer2_);
-
-  if (!api.TIFFClose(&tif).ok()) {
-    std::cerr << "TIFFClose error\n";
-  }
-
-  status_or_tif = api.TIFFOpen(srcfile_var.PtrBefore(), r_var.PtrBefore());
-  if (!status_or_tif.ok()) {
-    std::cerr << "Could not reopen " << srcfile << "\n";
-    return 1;
-  }
-
-  sapi::v::RemotePtr tif2(status_or_tif.value());
-  if (!tif2.GetValue()) {  // tif is NULL
-    std::cerr << "Could not reopen " << srcfile << "\n";
-    return 1;
-  }
-
-  sapi::v::Array<uint32> rgba_buffer_(128 * 128);
-
-  status_or_int =
-      api.TIFFReadRGBATile(&tif2, 1 * 128, 2 * 128, rgba_buffer_.PtrBoth());
-  if (!status_or_int.ok() || !status_or_int.value()) {
-    fprintf(stderr, "TIFFReadRGBATile() returned failure code.\n");
-    return 1;
-  }
-
-  pixel_status |=
-      CheckRgbaPixel(0, 15, 18, 0, 0, 18, 41, 255, 255, rgba_buffer_);
-  pixel_status |= CheckRgbaPixel(64, 0, 0, 0, 0, 0, 2, 255, 255, rgba_buffer_);
-  pixel_status |=
-      CheckRgbaPixel(512, 5, 6, 34, 36, 182, 196, 255, 255, rgba_buffer_);
-
-  if (!api.TIFFClose(&tif2).ok()) {
-    std::cerr << "TIFFClose erro\n";
-  }
-
-  if (pixel_status) {
-    std::cerr << "pixel_status is true, expected false";
-    return 1;
-  }
-
-  return 0;
+  return EXIT_SUCCESS;
 }
diff --git a/oss-internship-2020/libtiff/sandboxed.h b/oss-internship-2020/libtiff/sandboxed.h
index 70dbdff..168740b 100644
--- a/oss-internship-2020/libtiff/sandboxed.h
+++ b/oss-internship-2020/libtiff/sandboxed.h
@@ -41,6 +41,7 @@ class TiffSapiSandbox : public TiffSandbox {
         .AllowOpen()
         .AllowExit()
         .AllowStat()
+        .AllowMmap()
         .AllowSystemMalloc()
         .AllowSyscalls({
             __NR_futex,
@@ -48,7 +49,6 @@ class TiffSapiSandbox : public TiffSandbox {
             __NR_lseek,
             __NR_gettid,
             __NR_sysinfo,
-            __NR_mmap,
             __NR_munmap,
         });
 
@@ -63,7 +63,8 @@ class TiffSapiSandbox : public TiffSandbox {
     return builder.get()->BuildOrDie();
   }
 
-  std::string dir_, file_;
+  std::string dir_;
+  std::string file_;
 };
 
 }  // namespace
diff --git a/oss-internship-2020/libtiff/test/check_tag.cc b/oss-internship-2020/libtiff/test/check_tag.cc
index 72240e5..0f48835 100644
--- a/oss-internship-2020/libtiff/test/check_tag.cc
+++ b/oss-internship-2020/libtiff/test/check_tag.cc
@@ -14,12 +14,11 @@
 
 #include "check_tag.h"
 
-/* sapi functions:
- * TIFFGetField
- */
+// sapi functions:
+//  TIFFGetField
 
 void CheckShortField(TiffApi& api, sapi::v::RemotePtr& tif, const ttag_t field,
-                     const unsigned short value) {
+                     const uint16_t value) {
   sapi::v::UShort tmp(123);
   sapi::StatusOr<int> status_or_int;
 
@@ -33,7 +32,7 @@ void CheckShortField(TiffApi& api, sapi::v::RemotePtr& tif, const ttag_t field,
 
 void CheckShortPairedField(TiffApi& api, sapi::v::RemotePtr& tif,
                            const ttag_t field,
-                           const std::array<unsigned short, 2>& values) {
+                           const std::array<uint16_t, 2>& values) {
   sapi::v::UShort tmp0(123);
   sapi::v::UShort tmp1(456);
   sapi::StatusOr<int> status_or_int;
diff --git a/oss-internship-2020/libtiff/test/check_tag.h b/oss-internship-2020/libtiff/test/check_tag.h
index fd48e39..18a029c 100644
--- a/oss-internship-2020/libtiff/test/check_tag.h
+++ b/oss-internship-2020/libtiff/test/check_tag.h
@@ -12,13 +12,15 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <cstring>
+
 #include "helper.h"
 #include "tiffio.h"
 
 void CheckShortField(TiffApi&, sapi::v::RemotePtr& tif, const ttag_t field,
-                     const unsigned short value);
+                     const uint16_t value);
 void CheckShortPairedField(TiffApi& api, sapi::v::RemotePtr& tif,
                            const ttag_t field,
-                           const std::array<unsigned short, 2>& values);
+                           const std::array<uint16_t, 2>& values);
 void CheckLongField(TiffApi&, sapi::v::RemotePtr& tif, const ttag_t field,
                     const unsigned value);
diff --git a/oss-internship-2020/libtiff/test/defer_strile_writing.cc b/oss-internship-2020/libtiff/test/defer_strile_writing.cc
index cbaab14..67ff3c3 100644
--- a/oss-internship-2020/libtiff/test/defer_strile_writing.cc
+++ b/oss-internship-2020/libtiff/test/defer_strile_writing.cc
@@ -12,33 +12,36 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <cstdint>
+
 #include "helper.h"
 #include "tiffio.h"
 
-/* sapi functions:
- * TIFFOpen
- * TIFFClose
- * TIFFGetField
- * TIFFSetField
- * TIFFWriteCheck
- * TIFFSetDirectory
- * TIFFFreeDirectory
- * TIFFWriteScanline
- * TIFFWriteDirectory
- * TIFFCreateDirectory
- * TIFFReadEncodedTile
- * TIFFReadEncodedStrip
- * TIFFWriteEncodedTile
- * TIFFWriteEncodedStrip
- * TIFFDeferStrileArrayWriting
- * TIFFForceStrileArrayWriting
- */
+// sapi functions:
+//  TIFFOpen
+//  TIFFClose
+//  TIFFGetField
+//  TIFFSetField
+//  TIFFWriteCheck
+//  TIFFSetDirectory
+//  TIFFFreeDirectory
+//  TIFFWriteScanline
+//  TIFFWriteDirectory
+//  TIFFCreateDirectory
+//  TIFFReadEncodedTile
+//  TIFFReadEncodedStrip
+//  TIFFWriteEncodedTile
+//  TIFFWriteEncodedStrip
+//  TIFFDeferStrileArrayWriting
+//  TIFFForceStrileArrayWriting
+
+namespace { 
 
 #define TBS 256  // kTileBufferSize
-static const unsigned short kWidth = 1;
-static const unsigned short kBps = 8;
-static const unsigned short kRowsPerStrip = 1;
-static const unsigned short kSamplePerPixel = 1;
+constexpr uint16_t kWidth = 1;
+constexpr uint16_t kBps = 8;
+constexpr uint16_t kRowsPerStrip = 1;
+constexpr uint16_t kSamplePerPixel = 1;
 
 void TestWriting(const char* mode, int tiled, int height) {
   sapi::StatusOr<std::string> status_or_path =
@@ -320,3 +323,5 @@ TEST(SandboxTest, DeferStrileWriting) {
     TestWriting("wD", tiled, 1);
   }
 }
+
+} // namespace
diff --git a/oss-internship-2020/libtiff/test/helper.cc b/oss-internship-2020/libtiff/test/helper.cc
index 964c15d..b50fc1d 100644
--- a/oss-internship-2020/libtiff/test/helper.cc
+++ b/oss-internship-2020/libtiff/test/helper.cc
@@ -16,16 +16,10 @@
 
 #include <iostream>
 
-std::string inDir;
-
-std::string GetCWD() {
-  char cwd[PATH_MAX];
-  getcwd(cwd, sizeof(cwd));
-  return cwd;
-}
+static auto* g_in_dir = new std::string();
 
 std::string GetImagesDir() {
-  std::string cwd = GetCWD();
+  std::string cwd = sandbox2::file_util::fileops::GetCWD();
   auto find = cwd.rfind("/build");
   if (find == std::string::npos) {
     std::cerr << "Something went wrong: CWD don't contain build dir. "
@@ -38,8 +32,8 @@ std::string GetImagesDir() {
 }
 
 std::string GetFilePath(const std::string& filename) {
-  if (inDir.empty()) {
-    inDir = GetImagesDir();
+  if (g_in_dir->empty()) {
+    *g_in_dir = GetImagesDir();
   }
-  return sandbox2::file::JoinPath(inDir, filename);
+  return sandbox2::file::JoinPath(*g_in_dir, filename);
 }
diff --git a/oss-internship-2020/libtiff/test/long_tag.cc b/oss-internship-2020/libtiff/test/long_tag.cc
index a065204..e575ded 100644
--- a/oss-internship-2020/libtiff/test/long_tag.cc
+++ b/oss-internship-2020/libtiff/test/long_tag.cc
@@ -18,13 +18,14 @@
 #include "check_tag.h"
 #include "tiffio.h"
 
-/* sapi functions:
- * TIFFWriteScanline
- * TIFFOpen
- * TIFFClose
- * TIFFGetField (from check_tag.c)
- * TIFFSetField
- */
+// sapi functions:
+//  TIFFWriteScanline
+//  TIFFOpen
+//  TIFFClose
+//  TIFFGetField (from check_tag.c)
+//  TIFFSetField
+
+namespace {
 
 struct LongTag {
   ttag_t tag;
@@ -32,14 +33,13 @@ struct LongTag {
   unsigned value;
 };
 
-const std::vector<LongTag> long_tags = {
-    {TIFFTAG_SUBFILETYPE, 1,
-     FILETYPE_REDUCEDIMAGE | FILETYPE_PAGE | FILETYPE_MASK}};
+constexpr std::array<LongTag, 1> kLongTags = {
+	{TIFFTAG_SUBFILETYPE, 1, FILETYPE_REDUCEDIMAGE | FILETYPE_PAGE | FILETYPE_MASK}};
 #define SPP 3  // kSamplePerPixel
-static const unsigned kWidth = 1;
-static const unsigned kLength = 1;
-static const unsigned kBps = 8;
-static const unsigned kRowsPerStrip = 1;
+constexpr unsigned kWidth = 1;
+constexpr unsigned kLength = 1;
+constexpr unsigned kBps = 8;
+constexpr unsigned kRowsPerStrip = 1;
 
 TEST(SandboxTest, LongTag) {
   sapi::StatusOr<std::string> status_or_path =
@@ -52,8 +52,8 @@ TEST(SandboxTest, LongTag) {
   TiffSapiSandbox sandbox("", srcfile);
   ASSERT_THAT(sandbox.Init(), IsOk()) << "Couldn't initialize Sandboxed API";
 
-  std::array<unsigned char, SPP> buffer = {0, 127, 255};
-  sapi::v::Array<unsigned char> buffer_(buffer.data(), SPP);
+  std::array<uint8_t, SPP> buffer = {0, 127, 255};
+  sapi::v::Array<uint8_t> buffer_(buffer.data(), SPP);
 
   sapi::StatusOr<int> status_or_int;
   sapi::StatusOr<TIFF*> status_or_tif;
@@ -102,7 +102,7 @@ TEST(SandboxTest, LongTag) {
   EXPECT_THAT(status_or_int.value(), IsTrue())
       << "Can't set PhotometricInterpretation tag";
 
-  for (auto& tag : long_tags) {
+  for (auto& tag : kLongTags) {
     status_or_int = api.TIFFSetFieldU1(&tif, tag.tag, tag.value);
     ASSERT_THAT(status_or_int, IsOk()) << "TIFFSetFieldUShort1 fatal error";
     EXPECT_THAT(status_or_int.value(), IsTrue()) << "Can't set tag " << tag.tag;
@@ -126,10 +126,12 @@ TEST(SandboxTest, LongTag) {
   CheckLongField(api, tif2, TIFFTAG_IMAGELENGTH, kLength);
   CheckLongField(api, tif2, TIFFTAG_ROWSPERSTRIP, kRowsPerStrip);
 
-  for (auto& tag : long_tags) {
+  for (auto& tag : kLongTags) {
     CheckLongField(api, tif2, tag.tag, tag.value);
   }
 
   ASSERT_THAT(api.TIFFClose(&tif2), IsOk()) << "TIFFClose fatal error";
   unlink(srcfile.c_str());
 }
+
+} // namespace
diff --git a/oss-internship-2020/libtiff/test/raw_decode.cc b/oss-internship-2020/libtiff/test/raw_decode.cc
index 0a3f58e..d359316 100644
--- a/oss-internship-2020/libtiff/test/raw_decode.cc
+++ b/oss-internship-2020/libtiff/test/raw_decode.cc
@@ -12,30 +12,31 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <array>
 #include <cstring>
 
 #include "gtest/gtest.h"
 #include "helper.h"
 #include "tiffio.h"
 
-/* sapi functions:
- *    TIFFOpen
- *    TIFFClose
- *    TIFFGetField
- *    TIFFSetField
- *    TIFFTileSize
- *    TIFFReadRGBATile
- *    TIFFReadEncodedTile
- */
+// sapi functions:
+//  TIFFOpen
+//  TIFFClose
+//  TIFFGetField
+//  TIFFSetField
+//  TIFFTileSize
+//  TIFFReadRGBATile
+//  TIFFReadEncodedTile
 
-static const std::vector<unsigned char> cluster_0 = {0, 0, 2, 0, 138, 139};
-static const std::vector<unsigned char> cluster_64 = {0, 0, 9, 6, 134, 119};
-static const std::vector<unsigned char> cluster_128 = {44, 40, 63, 59, 230, 95};
+namespace {
 
-static int CheckCluster(int cluster,
-                        const sapi::v::Array<unsigned char> &buffer,
-                        const std::vector<unsigned char> &expected_cluster) {
-  unsigned char* target = buffer.GetData() + cluster * 6;
+constexpr std::array<uint8_t, 6> kCluster0 = {0, 0, 2, 0, 138, 139};
+constexpr std::array<uint8_t, 6> kCluster64 = {0, 0, 9, 6, 134, 119};
+constexpr std::array<uint8_t, 6> kCluster128 = {44, 40, 63, 59, 230, 95};
+
+int CheckCluster(int cluster, const sapi::v::Array<uint8_t> &buffer,
+                 const std::array<uint8_t, 6> &expected_cluster) {
+  uint8_t* target = buffer.GetData() + cluster * 6;
 
   bool comp = !(std::memcmp(target, expected_cluster.data(), 6) == 0);
 
@@ -50,10 +51,10 @@ static int CheckCluster(int cluster,
   return comp;
 }
 
-static int CheckRgbPixel(int pixel, int min_red, int max_red, int min_green,
-                         int max_green, int min_blue, int max_blue,
-                         const sapi::v::Array<unsigned char> &buffer) {
-  unsigned char* rgb = buffer.GetData() + 3 * pixel;
+int CheckRgbPixel(int pixel, int min_red, int max_red, int min_green,
+                  int max_green, int min_blue, int max_blue,
+                  const sapi::v::Array<uint8_t> &buffer) {
+  uint8_t* rgb = buffer.GetData() + 3 * pixel;
 
   bool comp =
       !(rgb[0] >= min_red && rgb[0] <= max_red && rgb[1] >= min_green &&
@@ -68,10 +69,9 @@ static int CheckRgbPixel(int pixel, int min_red, int max_red, int min_green,
   return comp;
 }
 
-static int CheckRgbaPixel(int pixel, int min_red, int max_red, int min_green,
-                          int max_green, int min_blue, int max_blue,
-                          int min_alpha, int max_alpha,
-                          const sapi::v::Array<unsigned> &buffer) {
+int CheckRgbaPixel(int pixel, int min_red, int max_red, int min_green,
+                   int max_green, int min_blue, int max_blue, int min_alpha,
+                   int max_alpha, const sapi::v::Array<unsigned> &buffer) {
   // RGBA images are upside down - adjust for normal ordering
   int adjusted_pixel = pixel % 128 + (127 - (pixel / 128)) * 128;
   unsigned rgba = buffer[adjusted_pixel];
@@ -133,16 +133,16 @@ TEST(SandboxTest, RawDecode) {
       << "tiles are " << status_or_long.value() << " bytes";
   sz = status_or_long.value();
 
-  sapi::v::Array<unsigned char> buffer_(sz);
+  sapi::v::Array<uint8_t> buffer_(sz);
   status_or_long = api.TIFFReadEncodedTile(&tif, 9, buffer_.PtrBoth(), sz);
   ASSERT_THAT(status_or_long, IsOk()) << "TIFFReadEncodedTile fatal error";
   EXPECT_THAT(status_or_long.value(), Eq(sz))
       << "Did not get expected result code from TIFFReadEncodedTile()("
       << (int)status_or_long.value() << " instead of " << (int)sz << ")";
 
-  ASSERT_FALSE(CheckCluster(0, buffer_, cluster_0) ||
-               CheckCluster(64, buffer_, cluster_64) ||
-               CheckCluster(128, buffer_, cluster_128))
+  ASSERT_FALSE(CheckCluster(0, buffer_, kCluster0) ||
+               CheckCluster(64, buffer_, kCluster64) ||
+               CheckCluster(128, buffer_, kCluster128))
       << "Clusters did not match expected results";
 
   status_or_int =
@@ -157,7 +157,7 @@ TEST(SandboxTest, RawDecode) {
       << "tiles are " << status_or_long.value() << " bytes";
   sz = status_or_long.value();
 
-  sapi::v::Array<unsigned char> buffer2_(sz);
+  sapi::v::Array<uint8_t> buffer2_(sz);
   status_or_long = api.TIFFReadEncodedTile(&tif, 9, buffer2_.PtrBoth(), sz);
   ASSERT_THAT(status_or_long, IsOk()) << "TIFFReadEncodedTile fatal error";
   EXPECT_THAT(status_or_long.value(), Eq(sz))
@@ -194,4 +194,6 @@ TEST(SandboxTest, RawDecode) {
   EXPECT_THAT(api.TIFFClose(&tif2), IsOk()) << "TIFFClose fatal error";
 
   EXPECT_THAT(pixel_status, IsFalse()) << "wrong encoding";
-}
\ No newline at end of file
+}
+
+} // namespace
diff --git a/oss-internship-2020/libtiff/test/short_tag.cc b/oss-internship-2020/libtiff/test/short_tag.cc
index d5a6bb1..5913d51 100644
--- a/oss-internship-2020/libtiff/test/short_tag.cc
+++ b/oss-internship-2020/libtiff/test/short_tag.cc
@@ -13,38 +13,40 @@
 // limitations under the License.
 
 #include <array>
+#include <cstdint>
 #include <vector>
 
 #include "check_tag.h"
 #include "tiffio.h"
 
-/* sapi functions:
- * TIFFWriteScanline
- * TIFFOpen
- * TIFFClose
- * TIFFGetField (from check_tag.c)
- * TIFFSetField
- */
+// sapi functions:
+//  TIFFWriteScanline
+//  TIFFOpen
+//  TIFFClose
+//  TIFFGetField (from check_tag.c)
+//  TIFFSetField
+
+namespace {
 
 #define SPP 3  // kSamplePerPixel
-static const unsigned short kWidth = 1;
-static const unsigned short kLength = 1;
-static const unsigned short kBps = 8;
-static const unsigned short kPhotometric = PHOTOMETRIC_RGB;
-static const unsigned short kRowsPerStrip = 1;
-static const unsigned short kPlanarConfig = PLANARCONFIG_CONTIG;
+constexpr uint16_t kWidth = 1;
+constexpr uint16_t kLength = 1;
+constexpr uint16_t kBps = 8;
+constexpr uint16_t kPhotometric = PHOTOMETRIC_RGB;
+constexpr uint16_t kRowsPerStrip = 1;
+constexpr uint16_t kPlanarConfig = PLANARCONFIG_CONTIG;
 
 struct SingleTag {
   const ttag_t tag;
-  const unsigned short value;
+  const uint16_t value;
 };
 
 struct PairedTag {
   const ttag_t tag;
-  const std::array<unsigned short, 2> values;
+  const std::array<uint16_t, 2> values;
 };
 
-static const std::vector<SingleTag> short_single_tags = {
+constexpr std::array<SingleTag, 9> kShortSingleTags = {{
     {TIFFTAG_COMPRESSION, COMPRESSION_NONE},
     {TIFFTAG_FILLORDER, FILLORDER_MSB2LSB},
     {TIFFTAG_ORIENTATION, ORIENTATION_BOTRIGHT},
@@ -53,13 +55,13 @@ static const std::vector<SingleTag> short_single_tags = {
     {TIFFTAG_MAXSAMPLEVALUE, 241},
     {TIFFTAG_INKSET, INKSET_MULTIINK},
     {TIFFTAG_NUMBEROFINKS, SPP},
-    {TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_UINT}};
+    {TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_UINT}}};
 
-static const std::vector<PairedTag> short_paired_tags = {
+constexpr std::array<PairedTag, 4> kShortPairedTags = {{
     {TIFFTAG_PAGENUMBER, {1, 1}},
     {TIFFTAG_HALFTONEHINTS, {0, 255}},
     {TIFFTAG_DOTRANGE, {8, 16}},
-    {TIFFTAG_YCBCRSUBSAMPLING, {2, 1}}};
+    {TIFFTAG_YCBCRSUBSAMPLING, {2, 1}}}};
 
 TEST(SandboxTest, ShortTag) {
   sapi::StatusOr<std::string> status_or_path =
@@ -72,8 +74,8 @@ TEST(SandboxTest, ShortTag) {
   TiffSapiSandbox sandbox("", srcfile);
   ASSERT_THAT(sandbox.Init(), IsOk()) << "Couldn't initialize Sandboxed API";
 
-  std::array<unsigned char, SPP> buffer = {0, 127, 255};
-  sapi::v::Array<unsigned char> buffer_(buffer.data(), SPP);
+  std::array<uint8_t, SPP> buffer = {0, 127, 255};
+  sapi::v::Array<uint8_t> buffer_(buffer.data(), SPP);
 
   sapi::StatusOr<int> status_or_int;
   sapi::StatusOr<TIFF*> status_or_tif;
@@ -123,13 +125,13 @@ TEST(SandboxTest, ShortTag) {
   EXPECT_THAT(status_or_int.value(), IsTrue())
       << "Can't set PhotometricInterpretation tag";
 
-  for (auto& tag : short_single_tags) {
+  for (auto& tag : kShortSingleTags) {
     status_or_int = api.TIFFSetFieldUShort1(&tif, tag.tag, tag.value);
     ASSERT_THAT(status_or_int, IsOk()) << "TIFFSetFieldUShort1 fatal error";
     EXPECT_THAT(status_or_int.value(), IsTrue()) << "Can't set tag " << tag.tag;
   }
 
-  for (auto& tag : short_paired_tags) {
+  for (auto& tag : kShortPairedTags) {
     status_or_int =
         api.TIFFSetFieldUShort2(&tif, tag.tag, tag.values[0], tag.values[1]);
     ASSERT_THAT(status_or_int, IsOk()) << "TIFFSetFieldUShort2 fatal error";
@@ -158,13 +160,15 @@ TEST(SandboxTest, ShortTag) {
   CheckLongField(api, tif2, TIFFTAG_ROWSPERSTRIP, kRowsPerStrip);
   CheckShortField(api, tif2, TIFFTAG_PLANARCONFIG, kPlanarConfig);
 
-  for (auto& tag : short_single_tags) {
+  for (auto& tag : kShortSingleTags) {
     CheckShortField(api, tif2, tag.tag, tag.value);
   }
 
-  for (auto& tag : short_paired_tags) {
+  for (auto& tag : kShortPairedTags) {
     CheckShortPairedField(api, tif2, tag.tag, tag.values);
   }
 
   ASSERT_THAT(api.TIFFClose(&tif2), IsOk()) << "TIFFClose fatal error";
 }
+
+} // namespace
diff --git a/oss-internship-2020/libtiff/wrapper/CMakeLists.txt b/oss-internship-2020/libtiff/wrapper/CMakeLists.txt
index 0be8ee7..6627455 100644
--- a/oss-internship-2020/libtiff/wrapper/CMakeLists.txt
+++ b/oss-internship-2020/libtiff/wrapper/CMakeLists.txt
@@ -26,4 +26,4 @@ target_link_libraries(wrapped_tiff
   sandbox2::temp_file
   sapi::sapi
   tiff
-)
\ No newline at end of file
+)
diff --git a/oss-internship-2020/libtiff/wrapper/func.h b/oss-internship-2020/libtiff/wrapper/func.h
index 4d841dc..3115ddb 100644
--- a/oss-internship-2020/libtiff/wrapper/func.h
+++ b/oss-internship-2020/libtiff/wrapper/func.h
@@ -17,10 +17,9 @@
 
 #include "tiffio.h"
 
-/* s - signed
- * u - unsigned
- * wrapper for variadic functions TIFFGetField and TIFFSetField
- */
+// wrapper for variadic functions TIFFGetField and TIFFSetField
+// s - signed
+// u - unsigned
 
 extern "C" {
 int TIFFGetField1(TIFF* tif, unsigned tag, void* param);