pw_tokenizer: Base64EncodedBufferSize function

Rename Base64EncodedSize to Base64EncodedBufferSize and have it include
the null terminator. This makes it easier to use directly to size
buffers for Base64 encoding.

Change-Id: Ied24eed67f8d3c5e42a405c98e0b20b30d543536
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/20300
Commit-Queue: Wyatt Hepler <hepler@google.com>
Reviewed-by: Ewout van Bekkum <ewout@google.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/pw_tokenizer/base64_test.cc b/pw_tokenizer/base64_test.cc
index e751b8196..fbbd06412 100644
--- a/pw_tokenizer/base64_test.cc
+++ b/pw_tokenizer/base64_test.cc
@@ -74,6 +74,7 @@ TEST_F(PrefixedBase64, Encode) {
 TEST_F(PrefixedBase64, Encode_EmptyInput_WritesPrefix) {
   EXPECT_EQ(1u, PrefixedBase64Encode(std::span<byte>(), base64_));
   EXPECT_EQ('$', base64_[0]);
+  EXPECT_EQ('\0', base64_[1]);
 }
 
 TEST_F(PrefixedBase64, Encode_EmptyOutput_WritesNothing) {
@@ -114,7 +115,7 @@ TEST_F(PrefixedBase64, EncodeToVector_Successful) {
 }
 
 TEST_F(PrefixedBase64, EncodeToVector_VectorTooSmall_OnlyNullTerminates) {
-  constexpr byte big[Base64EncodedSize(
+  constexpr byte big[Base64EncodedBufferSize(
       PW_TOKENIZER_CFG_ENCODING_BUFFER_SIZE_BYTES + 1)] = {};
 
   auto buffer = PrefixedBase64Encode(big);
@@ -122,6 +123,19 @@ TEST_F(PrefixedBase64, EncodeToVector_VectorTooSmall_OnlyNullTerminates) {
   EXPECT_EQ('\0', buffer[0]);
 }
 
+TEST_F(PrefixedBase64, Base64EncodedBufferSize_Empty_RoomForPrefixAndNull) {
+  EXPECT_EQ(2u, Base64EncodedBufferSize(0));
+}
+
+TEST_F(PrefixedBase64, Base64EncodedBufferSize_PositiveSizes) {
+  for (unsigned i = 1; i <= 3; ++i) {
+    EXPECT_EQ(6u, Base64EncodedBufferSize(i));
+  }
+  for (unsigned i = 4; i <= 6; ++i) {
+    EXPECT_EQ(10u, Base64EncodedBufferSize(i));
+  }
+}
+
 TEST_F(PrefixedBase64, Decode) {
   for (auto& [binary, base64] : kTestData) {
     EXPECT_EQ(binary.size(), PrefixedBase64Decode(base64, binary_));