implement separate rfc4251::(string|mpint|name_list) types

1 files changed, 26 insertions, 25 deletions

diff --git a/rfc4251_gmp.C b/rfc4251_gmp.C
index b4c369b..06b6cf6 100644
--- a/rfc4251_gmp.C
+++ b/rfc4251_gmp.C
@@ -1,9 +1,9 @@
 /*
- * rfc4251_gmp.C -- implements mpint/gmp conversions for rfc4251::string
+ * rfc4251_gmp.C -- implements mpint/mpz conversions for rfc4251::mpint
  *
  * these functions need linking against libgmp
  *
- * Copyright (C) 2013,2015 Timo Weingärtner <timo@tiwe.de>
+ * Copyright (C) 2013,2015,2021 Timo Weingärtner <timo@tiwe.de>
  *
  * This file is part of ssh-agent-filter.
  *
@@ -25,36 +25,37 @@
 
 namespace rfc4251 {
 
-string::string (mpz_srcptr x) {
-	if (mpz_sgn(x) == 0)
-		return;
-
-	auto const import_positive = [] (mpz_srcptr x, std::vector<char> & value) {
+mpint::mpint (mpz_srcptr x) {
+	auto const import_positive = [] (mpz_srcptr x, std::vector<char> & buf) {
 		size_t bits{mpz_sizeinbase(x, 2)};
 		size_t bytes{(bits + 7) / 8};
 		size_t extrabyte{(bits % 8) == 0}; // need extra byte if MSB is 1 to keep it non-negative
-		if (bytes + extrabyte > std::numeric_limits<uint32_t>::max())
-			throw std::length_error{"32-bit limit for rfc4251::string exceeded"};
-		value.resize(bytes + extrabyte);
-		value[0] = 0;
-		mpz_export(value.data() + extrabyte, nullptr, 1, 1, 1, 0, x);
+		check_length_against_limit(bytes + extrabyte);
+		buf.resize(bytes + extrabyte);
+		buf[0] = 0;
+		mpz_export(buf.data() + extrabyte, nullptr, 1, 1, 1, 0, x);
 	};
-	if (mpz_sgn(x) == 1)
-		import_positive(x, value);
-	else {
-		// handle two's complement: add 1, invert all bits
-		mpz_class tmp{x};
-		tmp += 1;
-		import_positive(tmp.get_mpz_t(), value);
-		for (auto & i : value)
-			i ^= 0xff;
+
+	switch (mpz_sgn(x)) {
+		case 0:
+			return;
+		case 1:
+			import_positive(x, buf);
+			return;
+		default:
+			// handle two's complement: add 1, invert all bits
+			mpz_class tmp{x};
+			tmp += 1;
+			import_positive(tmp.get_mpz_t(), buf);
+			for (auto & i : buf)
+				i ^= 0xff;
 	}
 }
 
-string::operator mpz_class () const {
-	mpz_class ret;
-	mpz_import(ret.get_mpz_t(), value.size(), 1, 1, 1, 0, value.data());
-	if (mpz_sizeinbase(ret.get_mpz_t(), 2) == value.size() * 8) { // negative
+mpint::operator mpz_class () const {
+	mpz_class ret{};
+	mpz_import(ret.get_mpz_t(), buf.size(), 1, 1, 1, 0, buf.data());
+	if (mpz_sizeinbase(ret.get_mpz_t(), 2) == buf.size() * 8) { // negative
 		mpz_com(ret.get_mpz_t(), ret.get_mpz_t());
 		ret += 1;
 		mpz_neg(ret.get_mpz_t(), ret.get_mpz_t());