sha1/md5: fix exception safety, remove copy, and own exception message

Author: Easton97-Jens

src/utils/sha1.h

@@ -18,6 +18,7 @@
 
 #include <array>
 #include <cassert>
+#include <cstddef>
 #include <exception>
 #include <string>
 #include <string_view>
@@ -67,13 +68,17 @@ class DigestImpl {
     static std::string hexdigest(const std::string& input) {
         try {
             const auto digestBytes = calculateDigest(input);
+            const auto *digestByteData =
+                static_cast<const std::byte *>(static_cast<const void *>(digestBytes.data()));
             return utils::string::string_to_hex(
-                digestBytes.data(), digestBytes.size());
+                digestByteData, digestBytes.size());
         } catch (const DigestCalculationException&) {
             assert(false);
             const std::array<unsigned char, DigestSize> digestBytes = {};
+            const auto *digestByteData =
+                static_cast<const std::byte *>(static_cast<const void *>(digestBytes.data()));
             return utils::string::string_to_hex(
-                digestBytes.data(), digestBytes.size());
+                digestByteData, digestBytes.size());
         }
     }
 

src/utils/string.h

@@ -16,6 +16,7 @@
 #ifndef SRC_UTILS_STRING_H_
 #define SRC_UTILS_STRING_H_
 
+#include <cstddef>
 #include <ctime>
 #include <string>
 #include <cstring>
@@ -241,14 +242,14 @@ inline unsigned char *c2x(unsigned what, unsigned char *where) {
 }
 
 
-inline std::string string_to_hex(const unsigned char *input, size_t size) {
+inline std::string string_to_hex(const std::byte *input, size_t size) {
     static const char* const lut = "0123456789abcdef";
 
     std::string a(size*2, 0);
     char *d = a.data();
 
     for (size_t i = 0; i < size; ++i) {
-        const unsigned char c = input[i];
+        const unsigned char c = std::to_integer<unsigned char>(input[i]);
         *d++ = lut[c >> 4];
         *d++ = lut[c & 15];
     }
@@ -257,6 +258,13 @@ inline std::string string_to_hex(const unsigned char *input, size_t size) {
 }
 
 
+inline std::string string_to_hex(const unsigned char *input, size_t size) {
+    return string_to_hex(
+        static_cast<const std::byte *>(static_cast<const void *>(input)),
+        size);
+}
+
+
 inline std::string string_to_hex(std::string_view input) {
     static const char* const lut = "0123456789abcdef";