Polish DecodeBase58

src/base58.cpp

@@ -45,46 +45,45 @@ static constexpr int ENCODE_GROUP_SIZE = 7; // Group bytes into longs, consideri
 
 [[nodiscard]] static bool DecodeBase58(const char* psz, std::vector<unsigned char>& vch, int max_ret_len)
 {
-    // Skip leading spaces.
     while (*psz && IsSpace(*psz))
-        psz++;
+        ++psz;
+
     // Skip and count leading '1's.
-    int zeroes = 0;
-    int length = 0;
-    while (*psz == '1') {
-        zeroes++;
-        if (zeroes > max_ret_len) return false;
-        psz++;
+    int leading = 0;
+    for (; *psz == '1'; ++psz) {
+        ++leading;
+        if (leading > max_ret_len) return false;
     }
+
     int size = 1 + strlen(psz) * LOG_58_256_RATIO / BASE_SCALE;
     std::vector<unsigned char> b256(size);
+
     // Process the characters.
-    static_assert(std::size(MAP_BASE58) == 256, "MAP_BASE58.size() should be 256"); // guarantee not out of range
-    while (*psz && !IsSpace(*psz)) {
-        // Decode base58 character
+    int length = 0;
+    for (; *psz && !IsSpace(*psz); ++psz) {
         int carry = MAP_BASE58[(uint8_t)*psz];
-        if (carry == -1)  // Invalid b58 character
-            return false;
+        if (carry == -1) return false;
+
         int i = 0;
-        for (std::vector<unsigned char>::reverse_iterator it = b256.rbegin(); (carry != 0 || i < length) && (it != b256.rend()); ++it, ++i) {
+        for (auto it = b256.rbegin(); (carry != 0 || i < length) && (it != b256.rend()); ++it, ++i) {
             carry += 58 * (*it);
             *it = carry % 256;
             carry /= 256;
         }
         assert(carry == 0);
         length = i;
-        if (length + zeroes > max_ret_len) return false;
-        psz++;
+        if (length + leading > max_ret_len) return false;
     }
     // Skip trailing spaces.
     while (IsSpace(*psz))
-        psz++;
+        ++psz;
     if (*psz != 0)
         return false;
-    std::vector<unsigned char>::iterator it = b256.begin() + (size - length);
+
+    auto it = b256.begin() + (size - length);
     // Copy result into output vector.
-    vch.reserve(zeroes + (b256.end() - it));
-    vch.assign(zeroes, 0x00);
+    vch.reserve(leading + (b256.end() - it));
+    vch.assign(leading, 0x00);
     while (it != b256.end())
         vch.push_back(*(it++));
     return true;