Merge bitcoin#9867: Replace remaining sprintf with snprintf

19cafc6 test: Replace remaining sprintf with snprintf (Wladimir J. van der Laan)
0a17714 uint256: replace sprintf with HexStr and reverse-iterator (Wladimir J. van der Laan)

Tree-SHA512: 2ba1dd4d25e1cbfff4d67b2f483448aa7c34ab5c799cddd48ba5826e5fa6df425abe35e244aaf4c52db9fccfb4d2a25a14bb4597bf9d1fce95991f270da6bb26

Author: laanwj

src/test/dbwrapper_tests.cpp

@@ -277,7 +277,7 @@ BOOST_AUTO_TEST_CASE(iterator_string_ordering)
     CDBWrapper dbw(ph, (1 << 20), true, false, false);
     for (int x=0x00; x<10; ++x) {
         for (int y = 0; y < 10; y++) {
-            sprintf(buf, "%d", x);
+            snprintf(buf, sizeof(buf), "%d", x);
             StringContentsSerializer key(buf);
             for (int z = 0; z < y; z++)
                 key += key;
@@ -293,12 +293,12 @@ BOOST_AUTO_TEST_CASE(iterator_string_ordering)
             seek_start = 0;
         else
             seek_start = 5;
-        sprintf(buf, "%d", seek_start);
+        snprintf(buf, sizeof(buf), "%d", seek_start);
         StringContentsSerializer seek_key(buf);
         it->Seek(seek_key);
         for (int x=seek_start; x<10; ++x) {
             for (int y = 0; y < 10; y++) {
-                sprintf(buf, "%d", x);
+                snprintf(buf, sizeof(buf), "%d", x);
                 std::string exp_key(buf);
                 for (int z = 0; z < y; z++)
                     exp_key += exp_key;

src/uint256.cpp

@@ -20,10 +20,7 @@ base_blob<BITS>::base_blob(const std::vector<unsigned char>& vch)
 template <unsigned int BITS>
 std::string base_blob<BITS>::GetHex() const
 {
-    char psz[sizeof(data) * 2 + 1];
-    for (unsigned int i = 0; i < sizeof(data); i++)
-        sprintf(psz + i * 2, "%02x", data[sizeof(data) - i - 1]);
-    return std::string(psz, psz + sizeof(data) * 2);
+    return HexStr(std::reverse_iterator<const uint8_t*>(data + sizeof(data)), std::reverse_iterator<const uint8_t*>(data));
 }
 
 template <unsigned int BITS>