rpc: make wide_difficulty hexadecimal

This should be friendlier for clients which don't have bignum support

3 files changed, 19 insertions, 1 deletions

diff --git a/src/cryptonote_basic/difficulty.cpp b/src/cryptonote_basic/difficulty.cpp
index 5162e53e6..859173aa5 100644
--- a/src/cryptonote_basic/difficulty.cpp
+++ b/src/cryptonote_basic/difficulty.cpp
@@ -239,4 +239,19 @@ namespace cryptonote {
     return res.convert_to<difficulty_type>();
   }
 
+  std::string hex(difficulty_type v)
+  {
+    static const char chars[] = "0123456789abcdef";
+    std::string s;
+    while (v > 0)
+    {
+      s.push_back(chars[(v & 0xf).convert_to<unsigned>()]);
+      v >>= 4;
+    }
+    if (s.empty())
+      s += "0";
+    std::reverse(s.begin(), s.end());
+    return "0x" + s;
+  }
+
 }
diff --git a/src/cryptonote_basic/difficulty.h b/src/cryptonote_basic/difficulty.h
index f7a9376fb..02ed89e5a 100644
--- a/src/cryptonote_basic/difficulty.h
+++ b/src/cryptonote_basic/difficulty.h
@@ -32,6 +32,7 @@
 
 #include <cstdint>
 #include <vector>
+#include <string>
 #include <boost/multiprecision/cpp_int.hpp>
 
 #include "crypto/hash.h"
@@ -58,4 +59,6 @@ namespace cryptonote
     bool check_hash_128(const crypto::hash &hash, difficulty_type difficulty);
     bool check_hash(const crypto::hash &hash, difficulty_type difficulty);
     difficulty_type next_difficulty(std::vector<std::uint64_t> timestamps, std::vector<difficulty_type> cumulative_difficulties, size_t target_seconds);
+
+    std::string hex(difficulty_type v);
 }
diff --git a/src/rpc/core_rpc_server.cpp b/src/rpc/core_rpc_server.cpp
index f5f1a2f9a..8c201097e 100644
--- a/src/rpc/core_rpc_server.cpp
+++ b/src/rpc/core_rpc_server.cpp
@@ -74,7 +74,7 @@ namespace
   void store_difficulty(cryptonote::difficulty_type difficulty, uint64_t &sdiff, std::string &swdiff, uint64_t &stop64)
   {
     sdiff = (difficulty << 64 >> 64).convert_to<uint64_t>();
-    swdiff = difficulty.convert_to<std::string>();
+    swdiff = cryptonote::hex(difficulty);
     stop64 = (difficulty >> 64).convert_to<uint64_t>();
   }
 }