diff --git a/include/string.hpp b/include/string.hpp
index 6ebf7887..70e71cfa 100644
--- a/include/string.hpp
+++ b/include/string.hpp
@@ -67,8 +67,7 @@ https://en.wikipedia.org/wiki/Base64
 std::string toBase64(const uint8_t* data, size_t dataLen);
 std::string toBase64(const std::vector<uint8_t>& data);
 /** Converts a Base64-encoded string to a byte array.
-`outLen` is set to the length of the byte array.
-If non-NULL, caller must delete[] the result.
+Throws std::runtime_error if string is invalid.
 */
 std::vector<uint8_t> fromBase64(const std::string& str);
 
@@ -77,6 +76,8 @@ std::vector<uint8_t> fromBase64(const std::string& str);
 std::vector<uint8_t> compress(const uint8_t* data, size_t dataLen);
 std::vector<uint8_t> compress(const std::vector<uint8_t>& data);
 /** Uncompress bytes with zlib.
+Before calling this function, set `dataLen` to the capacity of `data`.
+After returning, `dataLen` is set to the number of bytes written.
 Unfortunately the output buffer cannot be computed from the compressed data, so you may need to hard-code the maximum expected size.
 */
 void uncompress(const uint8_t* compressed, size_t compressedLen, uint8_t* data, size_t* dataLen);
diff --git a/src/string.cpp b/src/string.cpp
index 80eac59f..4de82dd0 100644
--- a/src/string.cpp
+++ b/src/string.cpp
@@ -158,7 +158,7 @@ float fuzzyScore(const std::string& s, const std::string& query) {
 std::string toBase64(const uint8_t* data, size_t dataLen) {
 	static const char alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 
-	size_t numBlocks = size_t((dataLen + 2) / 3);
+	size_t numBlocks = (dataLen + 2) / 3;
 	size_t strLen = numBlocks * 4;
 	std::string str;
 	str.reserve(strLen);