Remove functions which return strings

We don't want anything which does dynamic memory allocation in the library.

include/olm/crypto.hh

@@ -17,7 +17,6 @@
 
 #include <cstdint>
 #include <cstddef>
-#include <string>
 
 namespace olm {
 
@@ -27,7 +26,6 @@ static const std::size_t IV_LENGTH = 16;
 
 struct Curve25519PublicKey {
     std::uint8_t public_key[KEY_LENGTH];
-    std::string to_string() const;
 };
 
 

include/olm/memory.hh

@@ -87,23 +87,4 @@ std::uint8_t * store_array(
     return destination + sizeof(T);
 }
 
-/** convert an array of bytes to a string representation */
-template<typename T>
-std::string bytes_to_string(T start, T end) {
-    std::ostringstream ss;
-    ss << std::hex << std::setfill('0');
-    while (start != end) {
-        ss << std::setw(2) << static_cast<int>(*start++);
-        if (start != end) {
-            ss << ":";
-        }
-    }
-    return ss.str();
-}
-
-template<typename T>
-std::string bytes_to_string(T start, size_t len) {
-    return bytes_to_string(start, start+len);
-}
-
 } // namespace olm

src/crypto.cpp

@@ -101,11 +101,6 @@ inline static void hmac_sha256_final(
 
 } // namespace
 
-std::string olm::Curve25519PublicKey::to_string() const {
-    return olm::bytes_to_string(std::begin(public_key),
-                                std::end(public_key));
-};
-
 void olm::curve25519_generate_key(
     std::uint8_t const * random_32_bytes,
     olm::Curve25519KeyPair & key_pair