From 8792d59c67bfd49aa7113c72eacbcf17c9bc747e Mon Sep 17 00:00:00 2001
From: Cheng <cheng@>
Date: Tue, 30 Jul 2024 08:01:39 +0000
Subject: [PATCH] removed requirement for a blob field from base58

---
 src/mpir_and_base58.h | 42 +++++++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/src/mpir_and_base58.h b/src/mpir_and_base58.h
index 13f2389..d22b566 100644
--- a/src/mpir_and_base58.h
+++ b/src/mpir_and_base58.h
@@ -52,20 +52,22 @@ extern thread_local thread_local__* thl;
 namespace ro {
 	using ristretto255::scalar, ristretto255::point;
 
+	template <typename T> concept has_type_indentifier
+		= requires(T v) {
+			{ v.type_indentifier } -> std::convertible_to<uint64_t>;
+	};
+
 	auto fasthash(uint64_t, std::span<const uint64_t>)->uint32_t;
 	void right_justify_string(char*, char*);
 	bool is_alphanumeric_fixed_length(unsigned int, const char*);
 
-	template <class T> typename std::enable_if<
-		ro::blob_type<T>,
-		decltype(T::type_indentifier, uint32_t())
-	>::type fasthash(const T& p_blob) {
+	template <has_type_indentifier T> auto fasthash(const T& sc) {
 		static_assert(sizeof(T) % 8 == 0, "fasthash assumes a multiple of 8 bytes");
 		return fasthash(
 			T::type_indentifier,
 			std::span< const uint64_t >(
-				reinterpret_cast<const uint64_t*>(&p_blob.blob[0]),
-				p_blob.blob.size() / 8
+				reinterpret_cast<const uint64_t*>(&sc),
+				sizeof(sc) / 8
 				)
 		);
 	}
@@ -73,7 +75,7 @@ namespace ro {
 	void map_base_from_mpir58(char*);
 	void map_base_to_mpir58(const char*, char*, size_t);
 
-	template <typename T> class base58 : public CompileSizedString<
+	template <has_type_indentifier T> class base58 : public CompileSizedString<
 		((sizeof(T) * 8 + 4) * 4943ui64 + 28955ui64) / 28956ui64 - (std::is_same_v<std::remove_cvref_t<T>, scalar> ? 1 : 0)> {
 	public:
 		//	The rational number 4943 / 28956 is minisculy larger than log(2)/log(58)
@@ -83,7 +85,7 @@ namespace ro {
 		base58(const T&);
 		base58(const char* p);
 		static const char* bin(
-			typename const decltype(T::type_indentifier, char())* p,
+			const char* p,
 			T& sc
 		);
 		static void bin(const base58<T>& str, T& sc);
@@ -102,7 +104,7 @@ namespace ro {
 		}
 	};
 
-	template <class T> typename const decltype(base58<T>::length, T::type_indentifier, uint32_t())
+	template <has_type_indentifier T> const uint32_t
 		//		cannot be consteval or constexpr, because has to be called after the mpir temp values are constructed
 		check_range() {
 		if (thl == nullptr)thl = new thread_local__();
@@ -120,8 +122,8 @@ namespace ro {
 
 	template <class T> const uint32_t check_range_m{ check_range<T>() };
 
-	template <class T> const char* base58<T>::bin(
-		typename const decltype(T::type_indentifier, char())* p,
+	template <has_type_indentifier T> const char* base58<T>::bin(
+		const char* p,
 		T& sc
 	) {
 		const uint32_t range = check_range_m<T>;
@@ -134,12 +136,14 @@ namespace ro {
 			mpz_fdiv_qr(thl->q, thl->r, thl->n, mpir::ristretto25519_curve_order);
 		}
 		else {
-			mpz_fdiv_q_2exp(thl->q, thl->n, sizeof(sc.blob) * 8);
-			mpz_fdiv_r_2exp(thl->r, thl->n, sizeof(sc.blob) * 8);
+			mpz_fdiv_q_2exp(thl->q, thl->n, sizeof(sc) * 8);
+			mpz_fdiv_r_2exp(thl->r, thl->n, sizeof(sc) * 8);
 		}
 		size_t count;
-		mpz_export(&(sc.blob[0]), &count, -1, 1, -1, 0, thl->r);
-		if (count < sizeof(sc.blob))memset(&sc.blob[count], 0, sizeof(sc.blob) - count);
+		mpz_export(&(sc), &count, -1, 1, -1, 0, thl->r);
+		if (count < sizeof(sc)) {
+			memset(((byte*)&sc) + count, 0, sizeof(sc) - count);
+		}
 		mpir_ui ck{ (static_cast<uint64_t>(fasthash(sc)) * static_cast<uint64_t>(range)) >> 32 };
 		if (ck != mpz_get_ui(thl->q)) throw BadStringRepresentationOfCryptoIdException();
 		return p + base58<T>::length;
@@ -152,13 +156,13 @@ namespace ro {
 		const T& sc
 	) {
 		mpir_ui ck{ (static_cast<uint64_t>(fasthash(sc)) * static_cast<uint64_t>(check_range_m<T>)) >> 32 };
-		mpz_import(thl->n, sizeof(sc.blob), -1, 1, -1, 0, &sc.blob[0]);
+		mpz_import(thl->n, sizeof(sc), -1, 1, -1, 0, &sc);
 		if constexpr (std::is_same_v<std::remove_cvref_t<T>, scalar>) {
 			mpz_addmul_ui(thl->n, mpir::ristretto25519_curve_order, ck);
 		}
 		else {
 			mpz_set_ui(thl->r, ck);
-			mpz_mul_2exp(thl->r, thl->r, sizeof(sc.blob) * 8);
+			mpz_mul_2exp(thl->r, thl->r, sizeof(sc) * 8);
 			mpz_add(thl->n, thl->n, thl->r);
 		}
 		mpz_get_str(p, 58, thl->n);
@@ -169,11 +173,11 @@ namespace ro {
 		//	return value points to trailing null
 	}
 
-	template <class T> base58<T>::base58(const T& el) {
+	template <has_type_indentifier T> base58<T>::base58(const T& el) {
 		to_base58<T>(static_cast<char*>(*this), el);
 	}
 
-	template <class T> base58<T>::base58(const char* p) {
+	template <has_type_indentifier T> base58<T>::base58(const char* p) {
 		memmove(this, p, (this->length));
 		std::array<char, (this->length)> test;
 		map_base_to_mpir58(this, test, this->length);	//Force an exception for bad char