tests/unittests: Extend & clean up base64 tests

- Added unit test for `base64_estimate_{de,en}code_size()`
- Mark constant stuff as `const`
- Use `memcmp()` for comparing memory
- Do not use variable size arrays
- Various code style issue

tests/unittests/tests-base64/tests-base64.c

@@ -20,16 +20,17 @@
 
 static void test_base64_01_encode_string(void)
 {
-    unsigned char data_in[] = "Hello RIOT this is a base64 test!\n"
+    static const char data_in[] = "Hello RIOT this is a base64 test!\n"
                                   "This should work as intended.";
 
-    unsigned char expected_encoding[] = "SGVsbG8gUklPVCB0aGlzIGlzIGEgYmFzZTY0IHR"
+    static const char expected_encoding[] =
+        "SGVsbG8gUklPVCB0aGlzIGlzIGEgYmFzZTY0IHR"
         "lc3QhClRoaXMgc2hvdWxkIHdvcmsgYXMgaW50ZW5kZWQu";
 
-    size_t data_in_size = strlen((char *)data_in);
+    size_t data_in_size = strlen(data_in);
 
     size_t base64_out_size = 0;
-    unsigned char base64_out[ strlen((char *)expected_encoding) ];
+    char base64_out[sizeof(expected_encoding)];
 
     /*
     * @Note:
@@ -46,34 +47,34 @@ static void test_base64_01_encode_string(void)
 
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
-    for (int i = 0; i < (int)base64_out_size; ++i) {
+    TEST_ASSERT_MESSAGE((0 == memcmp(expected_encoding, base64_out,
-        TEST_ASSERT_MESSAGE(base64_out[i] == expected_encoding[i], \
+                                     base64_out_size)),
                         "encoding failed!(produced unexpected output)");
-    }
 
 #if (TEST_BASE64_SHOW_OUTPUT == 1)
     puts("Test 01 Encoded:");
 
-    for (int i = 0; i < (int)base64_out_size; ++i) {
+    for (size_t i = 0; i < base64_out_size; ++i) {
         printf("%c", base64_out[i]);
     }
 
-    printf("\nFrom:\n%s\n", (char *)data_in);
+    printf("\nFrom:\n%s\n", data_in);
 #endif
 }
 
 static void test_base64_02_decode_base64(void)
 {
-    unsigned char encoded_base64[] = "SGVsbG8gUklPVCB0aGlzIGlzIGEgYmFzZTY0IHRlc3Q"
+    static const char encoded_base64[] =
+        "SGVsbG8gUklPVCB0aGlzIGlzIGEgYmFzZTY0IHRlc3Q"
         "hClRoaXMgc2hvdWxkIHdvcmsgYXMgaW50ZW5kZWQu";
 
-    unsigned char expected_string[] = "Hello RIOT this is a base64 test!\n"
+    static const char expected_string[] = "Hello RIOT this is a base64 test!\n"
                                           "This should work as intended.";
 
-    size_t base64_size = strlen((char *)encoded_base64);
+    size_t base64_size = strlen(encoded_base64);
 
     size_t data_out_size = 0;
-    unsigned char data_out[ strlen((char *)expected_string) ];
+    unsigned char data_out[sizeof(expected_string)];
 
     int ret = base64_decode(encoded_base64, base64_size, NULL, &data_out_size);
     TEST_ASSERT_EQUAL_INT(BASE64_ERROR_BUFFER_OUT_SIZE, ret);
@@ -84,51 +85,49 @@ static void test_base64_02_decode_base64(void)
     ret = base64_decode(encoded_base64, base64_size, data_out, &data_out_size);
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
-    for (int i = 0; i < (int)data_out_size; ++i) {
+    TEST_ASSERT_MESSAGE((0 == memcmp(expected_string, data_out,
-        TEST_ASSERT_MESSAGE(data_out[i] == expected_string[i], \
+                                     data_out_size)),
                         "decoding failed!(produced unexpected output)");
-    }
 
 #if (TEST_BASE64_SHOW_OUTPUT == 1)
     puts("Test 02 Decoded:");
 
-    for (int i = 0; i < (int)data_out_size; ++i) {
+    for (size_t i = 0; i < data_out_size; ++i) {
         printf("%c", data_out[i]);
     }
 
-    printf("\nFrom:\n%s\n", (char *)encoded_base64);
+    printf("\nFrom:\n%s\n", encoded_base64);
 #endif
 }
 
 static void test_base64_03_single_character(void)
 {
     size_t element_size = 1;
-    unsigned char element[] = "1";
+    static const char element[] = "1";
 
-    size_t elementDecodeSize = 3;
+    unsigned char element_decode[3];
-    unsigned char elementDecode[3];
+    size_t element_decode_size = sizeof(element_decode);
 
-    size_t element_base64_out_size = 10;
     unsigned char element_base64_out[10];
+    size_t element_base64_out_size = sizeof(element_base64_out);
 
-    int ret = base64_encode(element, element_size, \
+    int ret = base64_encode(element, element_size,
                             element_base64_out, &element_base64_out_size);
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
-    ret = base64_decode(element_base64_out, element_base64_out_size, \
+    ret = base64_decode(element_base64_out, element_base64_out_size,
-                        elementDecode, &elementDecodeSize);
+                        element_decode, &element_decode_size);
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
-    for (int i = 0; i < (int)elementDecodeSize; ++i) {
+    TEST_ASSERT_MESSAGE((0 == memcmp(element, element_decode,
-        TEST_ASSERT_MESSAGE(element[i] == elementDecode[i], \
+                                     element_decode_size)),
-                            "decoding failed!(produced unexpected output)");
+                        "encoding failed!(produced unexpected output)");
-    }
 }
 
 static void test_base64_04_free_conversion(void)
 {
     size_t elements = 255;
-    unsigned char elm[elements];
+    char elm[elements];
 
     size_t elem_base64_out_size = 0;
     unsigned char elm_base64_out[((elements / 3) * 4) + (elements / 10)];
@@ -137,7 +136,7 @@ static void test_base64_04_free_conversion(void)
     unsigned char elem_base64_out_decoded[ elements + 10 ];
 
     /* fill some values */
-    for (int i = 0; i < (int)elements; ++i) {
+    for (size_t i = 0; i < elements; ++i) {
         elm[i] = i;
     }
 
@@ -147,23 +146,23 @@ static void test_base64_04_free_conversion(void)
     ret = base64_encode(elm, elements, elm_base64_out, &elem_base64_out_size);
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
-    ret = base64_decode(elm_base64_out, elem_base64_out_size, \
+    ret = base64_decode(elm_base64_out, elem_base64_out_size,
                         NULL, &elem_base64_out_decoded_size);
     TEST_ASSERT_EQUAL_INT(BASE64_ERROR_BUFFER_OUT_SIZE, ret);
 
-    ret = base64_decode(elm_base64_out, elem_base64_out_size, \
+    ret = base64_decode(elm_base64_out, elem_base64_out_size,
                         elem_base64_out_decoded, &elem_base64_out_decoded_size);
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
-    for (int i = 0; i < (int)elements; ++i) {
+    TEST_ASSERT_MESSAGE((0 == memcmp(elem_base64_out_decoded, elm,
-        TEST_ASSERT_MESSAGE(elem_base64_out_decoded[i] == elm[i], \
+                                     elements)),
                         "decoding failed!(produced unexpected output)");
 }
-}
 
 static void test_base64_05_decode_larger(void)
 {
-    unsigned char decodeit[] = "SG93IG11Y2ggd29vZCB3b3VsZCBhIHdvb2RjaHVjayBjaHVj"
+    static const char decodeit[] =
+        "SG93IG11Y2ggd29vZCB3b3VsZCBhIHdvb2RjaHVjayBjaHVj"
         "awppZiBhIHdvb2RjaHVjayBjb3VsZCBjaHVjayB3b29kPwpI"
         "ZSB3b3VsZCBjaHVjaywgaGUgd291bGQsIGFzIG11Y2ggYXMg"
         "aGUgY291bGQsCmFuZCBjaHVjayBhcyBtdWNoIHdvb2QgYXMg"
@@ -171,9 +170,9 @@ static void test_base64_05_decode_larger(void)
         "bGQgY2h1Y2sgd29vZC4==";
 
     size_t data_size = 199;
-    unsigned char data[data_size];
+    char data[data_size];
 
-    size_t decodeit_size = strlen((char *)decodeit);
+    size_t decodeit_size = strlen(decodeit);
 
     int ret = base64_decode(decodeit, decodeit_size, data, &data_size);
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
@@ -181,11 +180,11 @@ static void test_base64_05_decode_larger(void)
 #if (TEST_BASE64_SHOW_OUTPUT == 1)
     puts("Test 05 Decoded:");
 
-    for (int i = 0; i < (int)data_size; ++i) {
+    for (size_t i = 0; i < data_size; ++i) {
         printf("%c", data[i]);
     }
 
-    printf("\nFrom:\n%s\n", (char *)decodeit);
+    printf("\nFrom:\n%s\n", decodeit);
 #endif
 }
 
@@ -202,25 +201,26 @@ static void test_base64_06_stream_encode(void)
     *
     */
 
-    unsigned char stream_encode[] = "Peter Piper picked a peck of pickled peppers."
+    static const char stream_encode[] =
-                                    "\nA peck of pickled peppers Peter Piper picked."
+        "Peter Piper picked a peck of pickled peppers.\n"
-                                    "\nIf Peter Piper picked a peck of pickled peppers,"
+        "A peck of pickled peppers Peter Piper picked.\n"
-                                    "\nWhere's the peck of pickled peppers Peter Piper picked?";
+        "If Peter Piper picked a peck of pickled peppers,\n"
+        "Where's the peck of pickled peppers Peter Piper picked?";
 
     /* required output size +2 extra bytes */
     size_t encoded_size = 264 + 2;
     /* cppcheck-suppress unassignedVariable
      * (reason: the above array is used/assigned in base64_encode() using its pointer) */
-    unsigned char encode_result[encoded_size];
+    char encode_result[encoded_size];
 
-    int remain = strlen((char *)stream_encode);
+    int remain = strlen(stream_encode);
     int out_iter = 0;
 
     int ret = BASE64_SUCCESS;
 
     for (int i = 3; i < remain; (i += 3)) {
         size_t size_used = encoded_size - out_iter;
-        ret = base64_encode(stream_encode + (strlen((char *)stream_encode) - remain), \
+        ret = base64_encode(stream_encode + (strlen(stream_encode) - remain),
                             i, encode_result + out_iter, &size_used);
         TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
@@ -230,7 +230,7 @@ static void test_base64_06_stream_encode(void)
 
     /* this final chunk we want to encode and append is prime to 3 */
     size_t finish = encoded_size - out_iter;
-    ret = base64_encode(stream_encode + (strlen((char *)stream_encode) - remain), \
+    ret = base64_encode(stream_encode + (strlen(stream_encode) - remain),
                         remain, encode_result + out_iter, &finish);
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
@@ -238,11 +238,11 @@ static void test_base64_06_stream_encode(void)
     out_iter += finish;
     puts("Test 06 Encoded:");
 
-    for (int i = 0; i < (int)out_iter; ++i) {
+    for (size_t i = 0; i < out_iter; ++i) {
         printf("%c", encode_result[i]);
     }
 
-    printf("\nFrom:\n%s\n", (char *)stream_encode);
+    printf("\nFrom:\n%s\n", stream_encode);
 #endif
 }
 
@@ -255,7 +255,8 @@ static void test_base64_07_stream_decode(void)
     * The chunks passed to decode MUST be dividable by 4.
     */
 
-    unsigned char encoded[] = "UGV0ZXIgUGlwZXIgcGlja2VkIGEgcGVjayBvZiBwaWNrbGVkIH"
+    static const char encoded[] =
+        "UGV0ZXIgUGlwZXIgcGlja2VkIGEgcGVjayBvZiBwaWNrbGVkIH"
         "BlcHBlcnMuCkEgcGVjayBvZiBwaWNrbGVkIHBlcHBlcnMgUGV0"
         "ZXIgUGlwZXIgcGlja2VkLgpJZiBQZXRlciBQaXBlciBwaWNrZW"
         "QgYSBwZWNrIG9mIHBpY2tsZWQgcGVwcGVycywKV2hlcmUncyB0"
@@ -267,9 +268,9 @@ static void test_base64_07_stream_decode(void)
 
     /* cppcheck-suppress unassignedVariable
      * (reason: the above array is used/assigned in base64_decode() using its pointer) */
-    unsigned char stream_decoded[decoded_size];
+    char stream_decoded[decoded_size];
 
-    size_t encoded_size = strlen((char *)encoded);
+    size_t encoded_size = strlen(encoded);
     int remain = encoded_size;
     int out_iter = 0;
 
@@ -277,7 +278,7 @@ static void test_base64_07_stream_decode(void)
 
     for (int i = 4; i < remain; (i += 4)) {
         size_t size_used = decoded_size - out_iter;
-        ret = base64_decode(encoded + (encoded_size - remain), \
+        ret = base64_decode(encoded + (encoded_size - remain),
                             i, stream_decoded + out_iter, &size_used);
         TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
@@ -286,7 +287,7 @@ static void test_base64_07_stream_decode(void)
     }
 
     size_t finish = decoded_size - out_iter;
-    ret = base64_decode(encoded + (encoded_size - remain), \
+    ret = base64_decode(encoded + (encoded_size - remain),
                         remain, stream_decoded + out_iter, &finish);
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
@@ -294,37 +295,34 @@ static void test_base64_07_stream_decode(void)
     out_iter += finish;
     puts("Test 07 Decoded:");
 
-    for (int i = 0; i < (int)out_iter; ++i) {
+    for (size_t i = 0; i < out_iter; ++i) {
         printf("%c", stream_decoded[i]);
     }
 
-    printf("\nFrom:\n%s\n", (char *)encoded);
+    printf("\nFrom:\n%s\n", encoded);
 #endif
 }
 
 static void test_base64_08_encode_16_bytes(void)
 {
-    /* FIXME: init as enum here and below required,
+    unsigned char buffer[16];
-     * to fix folding-constant compiler error on OS X
+    size_t buffer_size = sizeof(buffer);
-     */
+    for (size_t i = 0; i < buffer_size; ++i) {
-    enum { buffer_size = 16 };
-    unsigned char buffer[buffer_size];
-    for (int i = 0; i < buffer_size; ++i) {
         buffer[i] = 'a';
     }
 
-    enum { expected_out_size = 24 };
+    char element_base64_out[24];
+    size_t expected_out_size = sizeof(element_base64_out);
     size_t element_base64_out_size = expected_out_size;
-    unsigned char element_base64_out[expected_out_size];
 
     size_t required_out_size = 0;
-    int ret = base64_encode(buffer, buffer_size, \
+    int ret = base64_encode(buffer, buffer_size,
                             element_base64_out, &required_out_size);
 
     TEST_ASSERT_EQUAL_INT(BASE64_ERROR_BUFFER_OUT_SIZE, ret);
     TEST_ASSERT_EQUAL_INT(required_out_size, expected_out_size);
 
-    ret = base64_encode(buffer, buffer_size, \
+    ret = base64_encode(buffer, buffer_size,
                         element_base64_out, &element_base64_out_size);
 
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
@@ -345,13 +343,13 @@ static void test_base64_09_encode_size_determination(void)
 
     // test 20 bytes input, expected 28 bytes output
     size_t required_out_size = 0;
-    int ret = base64_encode(buffer, buffer_size, \
+    int ret = base64_encode(buffer, buffer_size,
                             element_base64_out, &required_out_size);
 
     TEST_ASSERT_EQUAL_INT(BASE64_ERROR_BUFFER_OUT_SIZE, ret);
     TEST_ASSERT_EQUAL_INT(required_out_size, expected_out_size);
 
-    ret = base64_encode(buffer, buffer_size, \
+    ret = base64_encode(buffer, buffer_size,
                         element_base64_out, &element_base64_out_size);
 
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
@@ -359,7 +357,7 @@ static void test_base64_09_encode_size_determination(void)
 
     // test 19 bytes input, expected 28 bytes output
     required_out_size = 0;
-    ret = base64_encode(buffer, 19, \
+    ret = base64_encode(buffer, 19,
                         element_base64_out, &required_out_size);
 
     TEST_ASSERT_EQUAL_INT(BASE64_ERROR_BUFFER_OUT_SIZE, ret);
@@ -368,7 +366,7 @@ static void test_base64_09_encode_size_determination(void)
     // test 18 bytes input, expected 24 bytes output
     expected_out_size = 24;
     required_out_size = 0;
-    ret = base64_encode(buffer, 18, \
+    ret = base64_encode(buffer, 18,
                         element_base64_out, &required_out_size);
 
     TEST_ASSERT_EQUAL_INT(BASE64_ERROR_BUFFER_OUT_SIZE, ret);
@@ -377,7 +375,7 @@ static void test_base64_09_encode_size_determination(void)
     // test 17 bytes input, expected 24 bytes output
     expected_out_size = 24;
     required_out_size = 0;
-    ret = base64_encode(buffer, 17, \
+    ret = base64_encode(buffer, 17,
                         element_base64_out, &required_out_size);
 
     TEST_ASSERT_EQUAL_INT(BASE64_ERROR_BUFFER_OUT_SIZE, ret);
@@ -416,7 +414,7 @@ static void test_base64_11_urlsafe_encode_int(void)
     unsigned char expected_encoding[] = "-RAAAA==";
 
     size_t base64_out_size = 0;
-    unsigned char base64_out[ strlen((char *)expected_encoding) ];
+    char base64_out[sizeof(expected_encoding)];
 
     /*
     * @Note:
@@ -425,23 +423,22 @@ static void test_base64_11_urlsafe_encode_int(void)
     * This size is a lower bound estimation,
     * thus it can require few more bytes then the actual used size for the output.
     */
-    int ret = base64url_encode((void *)&data_in, sizeof(data_in), NULL, &base64_out_size);
+    int ret = base64url_encode(&data_in, sizeof(data_in), NULL, &base64_out_size);
 
     TEST_ASSERT_EQUAL_INT(BASE64_ERROR_BUFFER_OUT_SIZE, ret);
 
-    ret = base64url_encode((void *)&data_in, sizeof(data_in), base64_out, &base64_out_size);
+    ret = base64url_encode(&data_in, sizeof(data_in), base64_out, &base64_out_size);
 
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
-    for (int i = 0; i < (int)base64_out_size; ++i) {
+    TEST_ASSERT_MESSAGE((0 == memcmp(expected_encoding, base64_out,
-        TEST_ASSERT_MESSAGE(base64_out[i] == expected_encoding[i], \
+                                     base64_out_size)),
                         "encoding failed!(produced unexpected output)");
-    }
 
 #if (TEST_BASE64_SHOW_OUTPUT == 1)
     puts("Test 11 Encoded:");
 
-    for (int i = 0; i < (int)base64_out_size; ++i) {
+    for (size_t i = 0; i < base64_out_size; ++i) {
         printf("%c", base64_out[i]);
     }
 
@@ -451,10 +448,10 @@ static void test_base64_11_urlsafe_encode_int(void)
 
 static void test_base64_12_urlsafe_decode_int(void)
 {
-    unsigned char encoded_base64[] = "_____wAA==";
+    static const char encoded_base64[]  = "_____wAA==";
-    unsigned char expected[]       = {0xFF, 0xFF, 0xFF, 0xFF, 0x0, 0x0};
+    static const uint8_t expected[]     = {0xFF, 0xFF, 0xFF, 0xFF, 0x0, 0x0};
 
-    size_t base64_size = strlen((char *)encoded_base64);
+    size_t base64_size = strlen(encoded_base64);
 
     size_t data_out_size = 0;
     unsigned char data_out[sizeof(expected)];
@@ -468,22 +465,39 @@ static void test_base64_12_urlsafe_decode_int(void)
     ret = base64_decode(encoded_base64, base64_size, data_out, &data_out_size);
     TEST_ASSERT_EQUAL_INT(BASE64_SUCCESS, ret);
 
-    for (int i = 0; i < (int)data_out_size; ++i) {
+    TEST_ASSERT_MESSAGE((0 == memcmp(expected, data_out, data_out_size)),
-        TEST_ASSERT_MESSAGE(data_out[i] == expected[i], \
                         "decoding failed!(produced unexpected output)");
-    }
 
 #if (TEST_BASE64_SHOW_OUTPUT == 1)
     puts("Test 11 Decoded:");
 
-    for (int i = 0; i < (int)data_out_size; ++i) {
+    for (size_t i = 0; i < data_out_size; ++i) {
         printf("%x", data_out[i]);
     }
 
-    printf("\nFrom:\n%x\n", (char *)encoded_base64);
+    printf("\nFrom:\n%s\n", encoded_base64);
 #endif
 }
 
+static void test_base64_13_size_estimation(void) {
+    size_t expected = 0;
+    for (size_t i = 0; i < 33; i += 3) {
+        TEST_ASSERT_EQUAL_INT(expected, base64_estimate_encode_size(i + 0));
+        expected += 4;
+        TEST_ASSERT_EQUAL_INT(expected, base64_estimate_encode_size(i + 1));
+        TEST_ASSERT_EQUAL_INT(expected, base64_estimate_encode_size(i + 2));
+    }
+
+    expected = 0;
+    for (size_t i = 0; i < 44; i += 4) {
+        TEST_ASSERT_EQUAL_INT(expected, base64_estimate_decode_size(i + 0));
+        expected += 3;
+        TEST_ASSERT_EQUAL_INT(expected, base64_estimate_decode_size(i + 1));
+        TEST_ASSERT_EQUAL_INT(expected, base64_estimate_decode_size(i + 2));
+        TEST_ASSERT_EQUAL_INT(expected, base64_estimate_decode_size(i + 3));
+    }
+}
+
 Test *tests_base64_tests(void)
 {
     EMB_UNIT_TESTFIXTURES(fixtures) {
@@ -500,6 +514,7 @@ Test *tests_base64_tests(void)
         new_TestFixture(test_base64_10_decode_empty),
         new_TestFixture(test_base64_11_urlsafe_encode_int),
         new_TestFixture(test_base64_12_urlsafe_decode_int),
+        new_TestFixture(test_base64_13_size_estimation),
     };
 
     EMB_UNIT_TESTCALLER(base64_tests, NULL, NULL, fixtures);