utfcpp: Update to 4.0.4

13 files changed, 919 insertions, 0 deletions

diff --git a/lib/utfcpp/v4/tests/CMakeLists.txt b/lib/utfcpp/v4/tests/CMakeLists.txt
new file mode 100644
index 00000000..8a00a6a0
--- /dev/null
+++ b/lib/utfcpp/v4/tests/CMakeLists.txt
@@ -0,0 +1,56 @@
+cmake_minimum_required (VERSION 3.5)
+project(utfcpptests LANGUAGES CXX)
+enable_testing()
+
+add_library(${PROJECT_NAME} INTERFACE)
+
+include_directories("${PROJECT_SOURCE_DIR}/../source")
+
+add_executable(negative negative.cpp)
+add_executable(cpp11 test_cpp11.cpp)
+add_executable(cpp17 test_cpp17.cpp)
+add_executable(cpp20 test_cpp20.cpp)
+add_executable(apitests apitests.cpp)
+
+add_executable(noexceptionstests noexceptionstests.cpp)
+
+
+
+target_compile_options(${PROJECT_NAME} INTERFACE
+  $<$<CXX_COMPILER_ID:MSVC>:/W4>
+  $<$<NOT:$<CXX_COMPILER_ID:MSVC>>:-Wall -Wextra -Wpedantic -Wconversion>)
+
+target_compile_options(noexceptionstests PUBLIC -fno-exceptions)
+
+set_target_properties(negative apitests noexceptionstests
+                      PROPERTIES
+                      CXX_STANDARD 98
+                      CXX_STANDARD_REQUIRED YES
+                      CXX_EXTENSIONS NO)
+
+set_target_properties(cpp11
+                      PROPERTIES
+                      CXX_STANDARD 11
+                      CXX_STANDARD_REQUIRED YES
+                      CXX_EXTENSIONS NO)
+
+set_target_properties(cpp17
+                      PROPERTIES
+                      CXX_STANDARD 17
+                      CXX_STANDARD_REQUIRED YES
+                      CXX_EXTENSIONS NO)
+
+set_target_properties(cpp20
+                      PROPERTIES
+                      CXX_STANDARD 20
+                      CXX_STANDARD_REQUIRED YES
+                      CXX_EXTENSIONS NO)
+
+
+add_test(negative_test negative ${PROJECT_SOURCE_DIR}/test_data/utf8_invalid.txt)
+add_test(cpp11_test cpp11)
+add_test(cpp17_test cpp17)
+add_test(cpp20_test cpp20)
+add_test(api_test apitests)
+add_test(noexceptions_test noexceptionstests)
+
diff --git a/lib/utfcpp/v4/tests/apitests.cpp b/lib/utfcpp/v4/tests/apitests.cpp
new file mode 100644
index 00000000..083266d7
--- /dev/null
+++ b/lib/utfcpp/v4/tests/apitests.cpp
@@ -0,0 +1,6 @@
+#include "../extern/ftest/ftest.h"
+
+#include "test_checked_api.h"
+#include "test_checked_iterator.h"
+#include "test_unchecked_api.h"
+#include "test_unchecked_iterator.h"
diff --git a/lib/utfcpp/v4/tests/docker/Dockerfile b/lib/utfcpp/v4/tests/docker/Dockerfile
new file mode 100644
index 00000000..dcdd47d1
--- /dev/null
+++ b/lib/utfcpp/v4/tests/docker/Dockerfile
@@ -0,0 +1,5 @@
+FROM gcc:12.2
+
+RUN  apt-get update \
+  && apt-get install -y make g++ cmake git \
+  && rm -rf /var/lib/apt/lists/*
diff --git a/lib/utfcpp/v4/tests/negative.cpp b/lib/utfcpp/v4/tests/negative.cpp
new file mode 100644
index 00000000..f1bcc993
--- /dev/null
+++ b/lib/utfcpp/v4/tests/negative.cpp
@@ -0,0 +1,59 @@
+#include "utf8.h"
+using namespace utf8;
+
+#include <string>
+#include <iostream>
+#include <fstream>
+#include <algorithm>
+using namespace std;
+
+const unsigned INVALID_LINES[] = { 75, 76, 83, 84, 85, 93, 102, 103, 105, 106, 107, 108, 109, 110, 114, 115, 116, 117, 124, 125, 130, 135, 140, 145, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 169, 175, 176, 177, 207, 208, 209, 210, 211, 220, 221, 222, 223, 224, 232, 233, 234, 235, 236, 247, 248, 249, 250, 251, 252, 253, 257, 258, 259, 260, 261, 262, 263, 264};
+const unsigned* INVALID_LINES_END = INVALID_LINES + sizeof(INVALID_LINES)/sizeof(unsigned);
+
+int main(int argc, char** argv)
+{
+    string test_file_path;
+    if (argc == 2) 
+        test_file_path = argv[1];
+    else {
+        cout << "Wrong number of arguments" << endl;
+        return 1;
+    }
+    // Open the test file
+    ifstream fs8(test_file_path.c_str());
+    if (!fs8.is_open()) {
+        cout << "Could not open " << test_file_path << endl;
+        return 1;
+    }
+
+    // Read it line by line
+    unsigned int line_count = 0;
+    char byte;
+    while (!fs8.eof()) {
+        string line;
+        while ((byte = static_cast<char>(fs8.get())) != '\n' && !fs8.eof())
+            line.push_back(byte);
+
+        line_count++;
+        bool expected_valid = (find(INVALID_LINES, INVALID_LINES_END, line_count) == INVALID_LINES_END);
+        // Print out lines that contain unexpected invalid UTF-8
+        if (!is_valid(line.begin(), line.end())) {
+            if (expected_valid) {
+                cout << "Unexpected invalid utf-8 at line " << line_count << '\n';
+                return 1;
+            }
+
+            // try fixing it:
+            string fixed_line;
+            replace_invalid(line.begin(), line.end(), back_inserter(fixed_line));
+            if (!is_valid(fixed_line.begin(), fixed_line.end())) {
+                cout << "replace_invalid() resulted in an invalid utf-8 at line " << line_count << '\n';
+                return 1;
+            }
+        }
+        else if (!expected_valid) {
+            cout << "Invalid utf-8 NOT detected at line " << line_count << '\n';
+            return 1;
+        }
+    }
+}
diff --git a/lib/utfcpp/v4/tests/noexceptionstests.cpp b/lib/utfcpp/v4/tests/noexceptionstests.cpp
new file mode 100644
index 00000000..108ee750
--- /dev/null
+++ b/lib/utfcpp/v4/tests/noexceptionstests.cpp
@@ -0,0 +1,4 @@
+#include "../extern/ftest/ftest.h"
+
+#include "test_unchecked_api.h"
+#include "test_unchecked_iterator.h"
diff --git a/lib/utfcpp/v4/tests/test_checked_api.h b/lib/utfcpp/v4/tests/test_checked_api.h
new file mode 100644
index 00000000..54e9cf8f
--- /dev/null
+++ b/lib/utfcpp/v4/tests/test_checked_api.h
@@ -0,0 +1,233 @@
+#ifndef UTF8_FOR_CPP_TEST_CHECKED_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
+#define UTF8_FOR_CPP_TEST_CHECKED_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
+
+#include "utf8.h"
+
+#include <string>
+#include <vector>
+using namespace utf8;
+using namespace std;
+
+
+TEST(CheckedAPITests, test_append)
+{
+    unsigned char u[5] = {0,0,0,0,0};
+    append(0x0448, u);
+    EXPECT_EQ (u[0], 0xd1);
+    EXPECT_EQ (u[1], 0x88);
+    EXPECT_EQ (u[2], 0);
+    EXPECT_EQ (u[3], 0);
+    EXPECT_EQ (u[4], 0);
+
+    append(0x65e5, u);
+    EXPECT_EQ (u[0], 0xe6);
+    EXPECT_EQ (u[1], 0x97);
+    EXPECT_EQ (u[2], 0xa5);
+    EXPECT_EQ (u[3], 0);
+    EXPECT_EQ (u[4], 0);
+
+    append(0x3044, u);
+    EXPECT_EQ (u[0], 0xe3);
+    EXPECT_EQ (u[1], 0x81);
+    EXPECT_EQ (u[2], 0x84);
+    EXPECT_EQ (u[3], 0);
+    EXPECT_EQ (u[4], 0);
+
+    append(0x10346, u);
+    EXPECT_EQ (u[0], 0xf0);
+    EXPECT_EQ (u[1], 0x90);
+    EXPECT_EQ (u[2], 0x8d);
+    EXPECT_EQ (u[3], 0x86);
+    EXPECT_EQ (u[4], 0);
+
+    // Ensure no warnings with plain char
+    char c[2] = {0,0};
+    append('a', c);
+    EXPECT_EQ (c[0], 'a');
+    EXPECT_EQ (c[1], 0);
+}
+
+TEST(CheckedAPITests, test_append16)
+{
+    utfchar16_t u[5] = {0,0};
+    append16(0x0448, u);
+    EXPECT_EQ (u[0], 0x0448);
+    EXPECT_EQ (u[1], 0x0000);
+
+    append16(0x65e5, u);
+    EXPECT_EQ (u[0], 0x65e5);
+    EXPECT_EQ (u[1], 0x0000);
+
+    append16(0x10346, u);
+    EXPECT_EQ (u[0], 0xd800);
+    EXPECT_EQ (u[1], 0xdf46);
+}
+
+TEST(CheckedAPITests, test_next)
+{
+    const char* twochars = "\xe6\x97\xa5\xd1\x88";
+    const char* w = twochars;
+    unsigned int cp = next(w, twochars + 6);
+    EXPECT_EQ (cp, 0x65e5);
+    EXPECT_EQ (w, twochars + 3);
+
+    const char* threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    w = threechars;
+
+    cp = next(w, threechars + 9);
+    EXPECT_EQ (cp, 0x10346);
+    EXPECT_EQ (w, threechars + 4);
+
+    cp = next(w, threechars + 9);
+    EXPECT_EQ (cp, 0x65e5);
+    EXPECT_EQ (w, threechars + 7);
+
+    cp = next(w, threechars + 9);
+    EXPECT_EQ (cp, 0x0448);
+    EXPECT_EQ (w, threechars + 9);
+}
+
+TEST(CheckedAPITests, test_next16)
+{
+    const utfchar16_t u[3] = {0x65e5, 0xd800, 0xdf46};
+    const utfchar16_t* w = u;
+    utf8::utfchar32_t cp = next16(w, w + 3);
+    EXPECT_EQ (cp, 0x65e5);
+    EXPECT_EQ (w, u + 1);
+
+    cp = next16(w, w + 2);
+    EXPECT_EQ (cp, 0x10346);
+    EXPECT_EQ (w, u + 3);
+}
+
+TEST(CheckedAPITests, test_peek_next)
+{
+    const char* const cw = "\xe6\x97\xa5\xd1\x88";
+    unsigned int cp = peek_next(cw, cw + 6);
+    EXPECT_EQ (cp, 0x65e5);
+}
+
+TEST(CheckedAPITests, test_prior)
+{
+    const char* twochars = "\xe6\x97\xa5\xd1\x88";
+    const char* w = twochars + 3;
+    unsigned int cp = prior (w, twochars);
+    EXPECT_EQ (cp, 0x65e5);
+    EXPECT_EQ (w, twochars);
+
+    const char* threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    w = threechars + 9;
+    cp = prior(w, threechars);
+    EXPECT_EQ (cp, 0x0448);
+    EXPECT_EQ (w, threechars + 7);
+    cp = prior(w, threechars);
+    EXPECT_EQ (cp, 0x65e5);
+    EXPECT_EQ (w, threechars + 4);
+    cp = prior(w, threechars);
+    EXPECT_EQ (cp, 0x10346);
+    EXPECT_EQ (w, threechars);
+}
+
+TEST(CheckedAPITests, test_advance)
+{
+    const char* threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    const char* w = threechars;
+    advance(w, 2, threechars + 9);
+    EXPECT_EQ(w, threechars + 7);
+    advance(w, -2, threechars);
+    EXPECT_EQ(w, threechars);
+    advance(w, 3, threechars + 9);
+    EXPECT_EQ(w, threechars + 9);
+    advance(w, -2, threechars);
+    EXPECT_EQ(w, threechars + 4);
+    advance(w, -1, threechars);
+    EXPECT_EQ(w, threechars);
+}
+
+TEST(CheckedAPITests, test_distance)
+{
+    const char* twochars = "\xe6\x97\xa5\xd1\x88";
+    size_t dist = static_cast<size_t>(utf8::distance(twochars, twochars + 5));
+    EXPECT_EQ (dist, 2);
+}
+
+TEST(CheckedAPITests, test_utf32to8)
+{
+    unsigned int utf32string[] = {0x448, 0x65E5, 0x10346, 0};
+    string utf8result;
+    utf32to8(utf32string, utf32string + 3, back_inserter(utf8result));
+    EXPECT_EQ (utf8result.size(), 9);
+}
+
+TEST(CheckedAPITests, test_utf8to32)
+{
+    const char* twochars = "\xe6\x97\xa5\xd1\x88";
+    vector<unsigned int> utf32result;
+    utf8to32(twochars, twochars + 5, back_inserter(utf32result));
+    EXPECT_EQ (utf32result.size(), 2);
+}
+
+TEST(CheckedAPITests, test_utf16to8)
+{
+    unsigned short utf16string[] = {0x41, 0x0448, 0x65e5, 0xd834, 0xdd1e};
+    string utf8result;
+    utf16to8(utf16string, utf16string + 5, back_inserter(utf8result));
+    EXPECT_EQ (utf8result.size(), 10);
+}
+
+TEST(CheckedAPITests, test_utf8to16)
+{
+    char utf8_with_surrogates[] = "\xe6\x97\xa5\xd1\x88\xf0\x9d\x84\x9e";
+    vector <unsigned short> utf16result;
+    utf8to16(utf8_with_surrogates, utf8_with_surrogates + 9, back_inserter(utf16result));
+    EXPECT_EQ (utf16result.size(), 4);
+    EXPECT_EQ (utf16result[2], 0xd834);
+    EXPECT_EQ (utf16result[3], 0xdd1e);
+}
+
+TEST(CheckedAPITests, test_replace_invalid)
+{
+    char invalid_sequence[] = "a\x80\xe0\xa0\xc0\xaf\xed\xa0\x80z";
+    vector<char> replace_invalid_result;
+    replace_invalid (invalid_sequence, invalid_sequence + sizeof(invalid_sequence), std::back_inserter(replace_invalid_result), '?');
+    bool bvalid = is_valid(replace_invalid_result.begin(), replace_invalid_result.end());
+    EXPECT_TRUE (bvalid);
+    const char fixed_invalid_sequence[] = "a????z";
+    EXPECT_EQ (sizeof(fixed_invalid_sequence), replace_invalid_result.size());
+    EXPECT_TRUE (std::equal(replace_invalid_result.begin(), replace_invalid_result.begin() + sizeof(fixed_invalid_sequence), fixed_invalid_sequence));
+}
+
+TEST(CheckedAPITests, test_find_invalid)
+{
+    char utf_invalid[] = "\xe6\x97\xa5\xd1\x88\xfa";
+    const char* invalid = find_invalid(utf_invalid, utf_invalid + 6);
+    EXPECT_EQ (invalid, utf_invalid + 5);
+    invalid = find_invalid(utf_invalid);
+    EXPECT_EQ (invalid, utf_invalid + 5);
+}
+
+TEST(CheckedAPITests, test_is_valid)
+{
+    char utf_invalid[] = "\xe6\x97\xa5\xd1\x88\xfa";
+    bool bvalid = is_valid(utf_invalid, utf_invalid + 6);
+    EXPECT_FALSE (bvalid);
+    bvalid = is_valid(utf_invalid);
+    EXPECT_FALSE (bvalid);
+    char utf8_with_surrogates[] = "\xe6\x97\xa5\xd1\x88\xf0\x9d\x84\x9e";
+    bvalid = is_valid(utf8_with_surrogates, utf8_with_surrogates + 9);
+    EXPECT_TRUE (bvalid);
+    bvalid = is_valid(utf8_with_surrogates);
+    EXPECT_TRUE (bvalid);
+}
+
+TEST(CheckedAPITests, test_starts_with_bom)
+{
+    unsigned char byte_order_mark[] = {0xef, 0xbb, 0xbf};
+    bool bbom = starts_with_bom(byte_order_mark, byte_order_mark + sizeof(byte_order_mark));
+    EXPECT_TRUE (bbom);
+    const char* threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    bool no_bbom = starts_with_bom(threechars, threechars + sizeof(threechars));
+    EXPECT_FALSE (no_bbom);
+}
+
+#endif
diff --git a/lib/utfcpp/v4/tests/test_checked_iterator.h b/lib/utfcpp/v4/tests/test_checked_iterator.h
new file mode 100644
index 00000000..2829a734
--- /dev/null
+++ b/lib/utfcpp/v4/tests/test_checked_iterator.h
@@ -0,0 +1,35 @@
+#ifndef UTF8_FOR_CPP_TEST_CHECKED_ITERATOR_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
+#define UTF8_FOR_CPP_TEST_CHECKED_ITERATOR_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
+
+#include "utf8.h"
+
+using namespace utf8;
+
+
+TEST(CheckedIteratrTests, test_increment)
+{
+    const char* threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    utf8::iterator<const char*> it(threechars, threechars, threechars + 9);
+    utf8::iterator<const char*> it2 = it;
+    EXPECT_EQ (it2, it);
+    EXPECT_EQ (*it, 0x10346);
+    EXPECT_EQ (*(++it), 0x65e5);
+    EXPECT_EQ ((*it++), 0x65e5);
+    EXPECT_EQ (*it, 0x0448);
+    EXPECT_NE (it, it2);
+    utf8::iterator<const char*> endit (threechars + 9, threechars, threechars + 9);
+    EXPECT_EQ (++it, endit);
+}
+
+TEST(CheckedIteratrTests, test_decrement)
+{
+    const char* threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    utf8::iterator<const char*> it(threechars+9, threechars, threechars + 9);
+    EXPECT_EQ (*(--it), 0x0448);
+    EXPECT_EQ ((*it--), 0x0448);
+    EXPECT_EQ (*it, 0x65e5);
+    EXPECT_EQ (--it, utf8::iterator<const char*>(threechars, threechars, threechars + 9));
+    EXPECT_EQ (*it, 0x10346);
+}
+
+#endif
diff --git a/lib/utfcpp/v4/tests/test_cpp11.cpp b/lib/utfcpp/v4/tests/test_cpp11.cpp
new file mode 100644
index 00000000..e5219668
--- /dev/null
+++ b/lib/utfcpp/v4/tests/test_cpp11.cpp
@@ -0,0 +1,122 @@
+#include "../extern/ftest/ftest.h"
+#include "utf8.h"
+#include <string>
+using namespace utf8;
+using namespace std;
+
+#if __cplusplus >= 201103L // C++ 11 or later
+
+TEST(CPP11APITests, test_append)
+{
+    string u;
+    append(0x0448, u);
+    EXPECT_EQ (u[0], char(0xd1));
+    EXPECT_EQ (u[1], char(0x88));
+    EXPECT_EQ (u.length(), 2);
+
+    u.clear();
+    append(0x65e5, u);
+    EXPECT_EQ (u[0], char(0xe6));
+    EXPECT_EQ (u[1], char(0x97));
+    EXPECT_EQ (u[2], char(0xa5));
+    EXPECT_EQ (u.length(), 3);
+
+    u.clear();
+    append(0x3044, u);
+    EXPECT_EQ (u[0], char(0xe3));
+    EXPECT_EQ (u[1], char(0x81));
+    EXPECT_EQ (u[2], char(0x84));
+    EXPECT_EQ (u.length(), 3);
+
+    u.clear();
+    append(0x10346, u);
+    EXPECT_EQ (u[0], char(0xf0));
+    EXPECT_EQ (u[1], char(0x90));
+    EXPECT_EQ (u[2], char(0x8d));
+    EXPECT_EQ (u[3], char(0x86));
+    EXPECT_EQ (u.length(), 4);
+}
+
+TEST(CPP11APITests, test_append16)
+{
+    u16string u;
+    append16(0x0448, u);
+    EXPECT_EQ (u[0], char16_t(0x0448));
+    EXPECT_EQ (u.length(), 1);
+}
+
+TEST(CPP11APITests, test_utf16to8)
+{
+    u16string utf16string = {0x41, 0x0448, 0x65e5, 0xd834, 0xdd1e};
+    string u = utf16to8(utf16string);
+    EXPECT_EQ (u.size(), 10);
+
+    u16string h16 = u"h!";
+    string h8;
+    utf8::unchecked::utf16to8(h16.begin(), h16.end(), std::back_inserter(h8));
+    EXPECT_EQ (h8, "h!");
+}
+
+TEST(CPP11APITests, test_utf8to16)
+{
+    string utf8_with_surrogates = "\xe6\x97\xa5\xd1\x88\xf0\x9d\x84\x9e";
+    u16string utf16result = utf8to16(utf8_with_surrogates);
+    EXPECT_EQ (utf16result.size(), 4);
+    EXPECT_EQ (utf16result[2], 0xd834);
+    EXPECT_EQ (utf16result[3], 0xdd1e);
+    // Just to make sure it compiles with string literals
+    utf8to16(u8"simple");
+    utf8to16("simple");
+}
+
+TEST(CPP11APITests, test_utf32to8)
+{
+    u32string utf32string = {0x448, 0x65E5, 0x10346};
+    string utf8result = utf32to8(utf32string);
+    EXPECT_EQ (utf8result.size(), 9);
+}
+
+TEST(CPP11APITests, test_utf8to32)
+{
+    const char* twochars = "\xe6\x97\xa5\xd1\x88";
+    u32string utf32result = utf8to32(twochars);
+    EXPECT_EQ (utf32result.size(), 2);
+}
+
+TEST(CPP11APITests, test_find_invalid)
+{
+    string utf_invalid = "\xe6\x97\xa5\xd1\x88\xfa";
+    auto invalid = find_invalid(utf_invalid);
+    EXPECT_EQ (invalid, 5);
+}
+
+TEST(CPP11APITests, test_is_valid)
+{
+    string utf_invalid = "\xe6\x97\xa5\xd1\x88\xfa";
+    bool bvalid = is_valid(utf_invalid);
+    EXPECT_FALSE (bvalid);
+    string utf8_with_surrogates = "\xe6\x97\xa5\xd1\x88\xf0\x9d\x84\x9e";
+    bvalid = is_valid(utf8_with_surrogates);
+    EXPECT_TRUE (bvalid);
+}
+
+TEST(CPP11APITests, test_replace_invalid)
+{
+    string invalid_sequence = "a\x80\xe0\xa0\xc0\xaf\xed\xa0\x80z";
+    string replace_invalid_result = replace_invalid(invalid_sequence, '?');
+    bool bvalid = is_valid(replace_invalid_result);
+    EXPECT_TRUE (bvalid);
+    const string fixed_invalid_sequence = "a????z";
+    EXPECT_EQ(fixed_invalid_sequence, replace_invalid_result);
+}
+
+TEST(CPP11APITests, test_starts_with_bom)
+{
+    string byte_order_mark = {char(0xef), char(0xbb), char(0xbf)};
+    bool bbom = starts_with_bom(byte_order_mark);
+    EXPECT_TRUE (bbom);
+    string threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    bool no_bbom = starts_with_bom(threechars);
+    EXPECT_FALSE (no_bbom);
+}
+#endif  // C++ 11 or later
diff --git a/lib/utfcpp/v4/tests/test_cpp17.cpp b/lib/utfcpp/v4/tests/test_cpp17.cpp
new file mode 100644
index 00000000..a38e6f71
--- /dev/null
+++ b/lib/utfcpp/v4/tests/test_cpp17.cpp
@@ -0,0 +1,88 @@
+#include "../extern/ftest/ftest.h"
+#include "utf8.h"
+#include <string>
+using namespace utf8;
+using namespace std;
+
+#if __cplusplus >= 201703L // C++ 17 or later
+
+
+TEST(CPP17APITests, test_utf16to8)
+{
+    u16string utf16string = {0x41, 0x0448, 0x65e5, 0xd834, 0xdd1e};
+    u16string_view utf16stringview(utf16string);
+    string u = utf16to8(utf16stringview);
+    EXPECT_EQ (u.size(), 10);
+}
+
+TEST(CPP17APITests, test_utf8to16)
+{
+    string_view utf8_with_surrogates = "\xe6\x97\xa5\xd1\x88\xf0\x9d\x84\x9e";
+    u16string utf16result = utf8to16(utf8_with_surrogates);
+    EXPECT_EQ (utf16result.size(), 4);
+    EXPECT_EQ (utf16result[2], 0xd834);
+    EXPECT_EQ (utf16result[3], 0xdd1e);
+}
+
+TEST(CPP17APITests, test_utf32to8)
+{
+    u32string utf32string = {0x448, 0x65E5, 0x10346};
+    u32string_view utf32stringview(utf32string);
+    string utf8result = utf32to8(utf32stringview);
+    EXPECT_EQ (utf8result.size(), 9);
+}
+
+TEST(CPP17APITests, test_utf8to32)
+{
+    string_view twochars = "\xe6\x97\xa5\xd1\x88";
+    u32string utf32result = utf8to32(twochars);
+    EXPECT_EQ (utf32result.size(), 2);
+}
+
+TEST(CPP17APITests, test_find_invalid)
+{
+    string_view utf_invalid = "\xe6\x97\xa5\xd1\x88\xfa";
+    auto invalid = find_invalid(utf_invalid);
+    EXPECT_EQ (invalid, 5);
+}
+
+TEST(CPP17APITests, test_is_valid)
+{
+    string_view utf_invalid = "\xe6\x97\xa5\xd1\x88\xfa";
+    bool bvalid = is_valid(utf_invalid);
+    EXPECT_FALSE (bvalid);
+    string_view utf8_with_surrogates = "\xe6\x97\xa5\xd1\x88\xf0\x9d\x84\x9e";
+    bvalid = is_valid(utf8_with_surrogates);
+    EXPECT_TRUE (bvalid);
+}
+
+TEST(CPP17APITests, test_replace_invalid)
+{
+    string_view invalid_sequence = "a\x80\xe0\xa0\xc0\xaf\xed\xa0\x80z";
+    string replace_invalid_result = replace_invalid(invalid_sequence, '?');
+    bool bvalid = is_valid(replace_invalid_result);
+    EXPECT_TRUE (bvalid);
+    const string fixed_invalid_sequence = "a????z";
+    EXPECT_EQ(fixed_invalid_sequence, replace_invalid_result);
+}
+
+TEST(CPP17APITests, test_starts_with_bom)
+{
+    string byte_order_mark = {char(0xef), char(0xbb), char(0xbf)};
+    string_view byte_order_mark_view(byte_order_mark);
+    bool bbom = starts_with_bom(byte_order_mark_view);
+    EXPECT_TRUE (bbom);
+    string_view threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    bool no_bbom = starts_with_bom(threechars);
+    EXPECT_FALSE (no_bbom);
+}
+
+TEST(CPP17APITests, string_class_and_literals)
+{
+    const char* twochars = u8"ab";
+    EXPECT_TRUE (is_valid(twochars));
+    const string two_chars_string(twochars);
+    EXPECT_TRUE (is_valid(two_chars_string));
+}
+
+#endif  // C++ 11 or later
diff --git a/lib/utfcpp/v4/tests/test_cpp20.cpp b/lib/utfcpp/v4/tests/test_cpp20.cpp
new file mode 100644
index 00000000..50dbe30a
--- /dev/null
+++ b/lib/utfcpp/v4/tests/test_cpp20.cpp
@@ -0,0 +1,77 @@
+#include "../extern/ftest/ftest.h"
+#define UTF_CPP_CPLUSPLUS 202002L
+#include "utf8.h"
+#include <string>
+using namespace utf8;
+using namespace std;
+
+TEST(CPP20APITests, test_utf16tou8)
+{
+    u16string utf16string = {0x41, 0x0448, 0x65e5, 0xd834, 0xdd1e};
+    u16string_view utf16stringview{utf16string};
+    u8string u = utf16tou8(utf16string);
+    EXPECT_EQ (u.size(), 10);
+    u = utf16tou8(utf16stringview);
+    EXPECT_EQ (u.size(), 10);
+}
+
+TEST(CPP20APITests, tes20t_utf8to16)
+{
+    u8string utf8_with_surrogates{u8"\xe6\x97\xa5\xd1\x88\xf0\x9d\x84\x9e"};
+    u16string utf16result = utf8to16(utf8_with_surrogates);
+    EXPECT_EQ (utf16result.size(), 4);
+    EXPECT_EQ (utf16result[2], 0xd834);
+    EXPECT_EQ (utf16result[3], 0xdd1e);
+}
+
+TEST(CPP20APITests, test_utf32tou8)
+{
+    u32string utf32string = {0x448, 0x65E5, 0x10346};
+    u32string_view utf32stringview{utf32string};
+    u8string utf8result = utf32tou8(utf32stringview);
+    EXPECT_EQ (utf8result.size(), 9);
+}
+
+TEST(CPP20APITests, test_utf8to32)
+{
+    u8string twochars = u8"\xe6\x97\xa5\xd1\x88";
+    u32string utf32result = utf8to32(twochars);
+    EXPECT_EQ (utf32result.size(), 2);
+}
+
+TEST(CPP20APITests, test_find_invalid)
+{
+    u8string utf_invalid = u8"\xe6\x97\xa5\xd1\x88\xfa";
+    auto invalid = find_invalid(utf_invalid);
+    EXPECT_EQ (invalid, 5);
+}
+
+TEST(CPP20APITests, test_is_valid)
+{
+    u8string utf_invalid = u8"\xe6\x97\xa5\xd1\x88\xfa";
+    bool bvalid = is_valid(utf_invalid);
+    EXPECT_FALSE (bvalid);
+    u8string utf8_with_surrogates = u8"\xe6\x97\xa5\xd1\x88\xf0\x9d\x84\x9e";
+    bvalid = is_valid(utf8_with_surrogates);
+    EXPECT_TRUE (bvalid);
+}
+
+TEST(CPP20APITests, test_replace_invalid)
+{
+    u8string invalid_sequence = u8"a\x80\xe0\xa0\xc0\xaf\xed\xa0\x80z";
+    u8string replace_invalid_result = replace_invalid(invalid_sequence, u8'?');
+    bool bvalid = is_valid(replace_invalid_result);
+    EXPECT_TRUE (bvalid);
+    const u8string fixed_invalid_sequence = u8"a????z";
+    EXPECT_EQ(fixed_invalid_sequence, replace_invalid_result);
+}
+
+TEST(CPP20APITests, test_starts_with_bom)
+{
+    u8string byte_order_mark = u8"\xef\xbb\xbf";
+    bool bbom = starts_with_bom(byte_order_mark);
+    EXPECT_TRUE (bbom);
+    u8string threechars = u8"\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    bool no_bbom = starts_with_bom(threechars);
+    EXPECT_FALSE (no_bbom);
+}
diff --git a/lib/utfcpp/v4/tests/test_data/utf8_invalid.txt b/lib/utfcpp/v4/tests/test_data/utf8_invalid.txt
new file mode 100644
index 00000000..ae831593
--- /dev/null
+++ b/lib/utfcpp/v4/tests/test_data/utf8_invalid.txt
diff --git a/lib/utfcpp/v4/tests/test_unchecked_api.h b/lib/utfcpp/v4/tests/test_unchecked_api.h
new file mode 100644
index 00000000..aa0cf697
--- /dev/null
+++ b/lib/utfcpp/v4/tests/test_unchecked_api.h
@@ -0,0 +1,198 @@
+#ifndef UTF8_FOR_CPP_TEST_UNCHECKED_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
+#define UTF8_FOR_CPP_TEST_UNCHECKED_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
+
+#include "utf8/unchecked.h"
+
+#include <string>
+#include <vector>
+
+using namespace std;
+
+TEST(UnCheckedAPITests, test_append)
+{
+    unsigned char u[5] = {0,0,0,0,0};
+    utf8::unchecked::append(0x0448, u);
+    EXPECT_EQ (u[0], 0xd1);
+    EXPECT_EQ (u[1], 0x88);
+    EXPECT_EQ (u[2], 0);
+    EXPECT_EQ (u[3], 0);
+    EXPECT_EQ (u[4], 0);
+
+    utf8::unchecked::append(0x65e5, u);
+    EXPECT_EQ (u[0], 0xe6);
+    EXPECT_EQ (u[1], 0x97);
+    EXPECT_EQ (u[2], 0xa5);
+    EXPECT_EQ (u[3], 0);
+    EXPECT_EQ (u[4], 0);
+
+    utf8::unchecked::append(0x3044, u);
+    EXPECT_EQ (u[0], 0xe3);
+    EXPECT_EQ (u[1], 0x81);
+    EXPECT_EQ (u[2], 0x84);
+    EXPECT_EQ (u[3], 0);
+    EXPECT_EQ (u[4], 0);
+
+    utf8::unchecked::append(0x10346, u);
+    EXPECT_EQ (u[0], 0xf0);
+    EXPECT_EQ (u[1], 0x90);
+    EXPECT_EQ (u[2], 0x8d);
+    EXPECT_EQ (u[3], 0x86);
+    EXPECT_EQ (u[4], 0);
+}
+
+TEST(UnCheckedAPITests, test_append16)
+{
+    unsigned short u[5] = {0,0};
+    utf8::unchecked::append16(0x0448, u);
+    EXPECT_EQ (u[0], 0x0448);
+    EXPECT_EQ (u[1], 0x0000);
+
+    utf8::unchecked::append16(0x65e5, u);
+    EXPECT_EQ (u[0], 0x65e5);
+    EXPECT_EQ (u[1], 0x0000);
+
+    utf8::unchecked::append16(0x10346, u);
+    EXPECT_EQ (u[0], 0xd800);
+    EXPECT_EQ (u[1], 0xdf46);
+}
+
+TEST(UnCheckedAPITests, test_next)
+{
+    const char* twochars = "\xe6\x97\xa5\xd1\x88";
+    const char* w = twochars;
+    unsigned int cp = utf8::unchecked::next(w);
+    EXPECT_EQ (cp, 0x65e5);
+    EXPECT_EQ (w, twochars + 3);
+
+    const char* threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    w = threechars;
+
+    cp = utf8::unchecked::next(w);
+    EXPECT_EQ (cp, 0x10346);
+    EXPECT_EQ (w, threechars + 4);
+
+    cp = utf8::unchecked::next(w);
+    EXPECT_EQ (cp, 0x65e5);
+    EXPECT_EQ (w, threechars + 7);
+
+    cp = utf8::unchecked::next(w);
+    EXPECT_EQ (cp, 0x0448);
+    EXPECT_EQ (w, threechars + 9);
+}
+
+TEST(UnCheckedAPITests, test_next16)
+{
+    const utf8::utfchar16_t u[3] = {0x65e5, 0xd800, 0xdf46};
+    const utf8::utfchar16_t* w = u;
+    utf8::utfchar32_t cp = utf8::unchecked::next16(w);
+    EXPECT_EQ (cp, 0x65e5);
+    EXPECT_EQ (w, u + 1);
+
+    cp = utf8::unchecked::next16(w);
+    EXPECT_EQ (cp, 0x10346);
+    EXPECT_EQ (w, u + 3);
+}
+
+TEST(UnCheckedAPITests, test_peek_next)
+{
+    const char* const cw = "\xe6\x97\xa5\xd1\x88";
+    unsigned int cp = utf8::unchecked::peek_next(cw);
+    EXPECT_EQ (cp, 0x65e5);
+}
+
+TEST(UnCheckedAPITests, test_prior)
+{
+    const char* twochars = "\xe6\x97\xa5\xd1\x88";
+    const char* w = twochars + 3;
+    unsigned int cp = utf8::unchecked::prior (w);
+    EXPECT_EQ (cp, 0x65e5);
+    EXPECT_EQ (w, twochars);
+
+    const char* threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    w = threechars + 9;
+    cp = utf8::unchecked::prior(w);
+    EXPECT_EQ (cp, 0x0448);
+    EXPECT_EQ (w, threechars + 7);
+    cp = utf8::unchecked::prior(w);
+    EXPECT_EQ (cp, 0x65e5);
+    EXPECT_EQ (w, threechars + 4);
+    cp = utf8::unchecked::prior(w);
+    EXPECT_EQ (cp, 0x10346);
+    EXPECT_EQ (w, threechars);
+}
+
+TEST(UnCheckedAPITests, test_advance)
+{
+    const char* threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    const char* w = threechars;
+    utf8::unchecked::advance(w, 2);
+    EXPECT_EQ(w, threechars + 7);
+    utf8::unchecked::advance(w, -2);
+    EXPECT_EQ(w, threechars);
+    utf8::unchecked::advance(w, 3);
+    EXPECT_EQ(w, threechars + 9);
+    utf8::unchecked::advance(w, -2);
+    EXPECT_EQ(w, threechars + 4);
+    utf8::unchecked::advance(w, -1);
+    EXPECT_EQ(w, threechars);
+}
+
+TEST(UnCheckedAPITests, test_distance)
+{
+    const char* twochars = "\xe6\x97\xa5\xd1\x88";
+    size_t dist = static_cast<size_t>(utf8::unchecked::distance(twochars, twochars + 5));
+    EXPECT_EQ (dist, 2);
+}
+
+TEST(UnCheckedAPITests, test_utf32to8)
+{
+    unsigned int utf32string[] = {0x448, 0x65E5, 0x10346, 0};
+    string utf8result;
+    utf8::unchecked::utf32to8(utf32string, utf32string + 3, back_inserter(utf8result));
+    EXPECT_EQ (utf8result.size(), 9);
+}
+
+TEST(UnCheckedAPITests, test_utf8to32)
+{
+    const char* twochars = "\xe6\x97\xa5\xd1\x88";
+    vector<unsigned int> utf32result;
+    utf8::unchecked::utf8to32(twochars, twochars + 5, back_inserter(utf32result));
+    EXPECT_EQ (utf32result.size(), 2);
+}
+
+TEST(UnCheckedAPITests, test_utf16to8)
+{
+    unsigned short utf16string[] = {0x41, 0x0448, 0x65e5, 0xd834, 0xdd1e};
+    string utf8result;
+    utf8::unchecked::utf16to8(utf16string, utf16string + 5, back_inserter(utf8result));
+    EXPECT_EQ (utf8result.size(), 10);
+
+    utf8result.clear();
+    unsigned short highsurrogateonly[] = {0xd800};
+    utf8::unchecked::utf16to8(highsurrogateonly, highsurrogateonly + 1, back_inserter(utf8result));
+    EXPECT_TRUE(true); // we didn't crash
+}
+
+TEST(UnCheckedAPITests, test_utf8to16)
+{
+    char utf8_with_surrogates[] = "\xe6\x97\xa5\xd1\x88\xf0\x9d\x84\x9e";
+    vector <unsigned short> utf16result;
+    utf8::unchecked::utf8to16(utf8_with_surrogates, utf8_with_surrogates + 9, back_inserter(utf16result));
+    EXPECT_EQ (utf16result.size(), 4);
+    EXPECT_EQ (utf16result[2], 0xd834);
+    EXPECT_EQ (utf16result[3], 0xdd1e);
+}
+
+TEST(UnCheckedAPITests, test_replace_invalid)
+{
+    char invalid_sequence[] = "a\x80\xe0\xa0\xc0\xaf\xed\xa0\x80z";
+    vector<char> replace_invalid_result;
+    utf8::unchecked::replace_invalid (invalid_sequence, invalid_sequence + sizeof(invalid_sequence), std::back_inserter(replace_invalid_result), '?');
+    bool bvalid = utf8::is_valid(replace_invalid_result.begin(), replace_invalid_result.end());
+    EXPECT_TRUE (bvalid);
+    const char fixed_invalid_sequence[] = "a????z";
+    EXPECT_EQ (sizeof(fixed_invalid_sequence), replace_invalid_result.size());
+    EXPECT_TRUE (std::equal(replace_invalid_result.begin(), replace_invalid_result.begin() + sizeof(fixed_invalid_sequence), fixed_invalid_sequence));
+}
+
+#endif
diff --git a/lib/utfcpp/v4/tests/test_unchecked_iterator.h b/lib/utfcpp/v4/tests/test_unchecked_iterator.h
new file mode 100644
index 00000000..4294232d
--- /dev/null
+++ b/lib/utfcpp/v4/tests/test_unchecked_iterator.h
@@ -0,0 +1,36 @@
+#ifndef UTF8_FOR_CPP_TEST_UNCHECKED_ITERATOR_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
+#define UTF8_FOR_CPP_TEST_UNCHECKED_ITERATOR_H_2675DCD0_9480_4c0c_B92A_CC14C027B731
+
+#include "utf8/unchecked.h"
+
+using namespace utf8::unchecked;
+
+
+TEST(UnCheckedIteratrTests, test_increment)
+{
+    const char* threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    utf8::unchecked::iterator<const char*> it(threechars);
+    utf8::unchecked::iterator<const char*> it2 = it;
+    EXPECT_EQ (it2, it);
+    EXPECT_EQ (*it, 0x10346);
+    EXPECT_EQ (*(++it), 0x65e5);
+    EXPECT_EQ ((*it++), 0x65e5);
+    EXPECT_EQ (*it, 0x0448);
+    EXPECT_NE (it, it2);
+    utf8::unchecked::iterator<const char*> endit (threechars + 9);
+    EXPECT_EQ (++it, endit);
+}
+
+TEST(UnCheckedIteratrTests, test_decrement)
+{
+    const char* threechars = "\xf0\x90\x8d\x86\xe6\x97\xa5\xd1\x88";
+    utf8::unchecked::iterator<const char*> it(threechars+9);
+    EXPECT_EQ (*(--it), 0x0448);
+    EXPECT_EQ ((*it--), 0x0448);
+    EXPECT_EQ (*it, 0x65e5);
+    EXPECT_EQ (--it, utf8::unchecked::iterator<const char*>(threechars));
+    EXPECT_EQ (*it, 0x10346);
+
+}
+
+#endif