Merge #19706: refactor: make EncodeBase58{Check} consume Spans

356988e util: make EncodeBase58Check consume Spans (Sebastian Falbesoner)
f0fce06 util: make EncodeBase58 consume Spans (Sebastian Falbesoner)

Pull request description:

  This PR improves the interfaces for the functions `EncodeBase58{Check}` by using Spans, in a similar fashion to e.g. PRs #19660, #19687. Note that on the master branch there are currently two versions of `EncodeBase58`: one that takes two pointers (marking begin and end) and another one that takes a `std::vector<unsigned char>` const-ref. The PR branch only leaves one generic Span-interface, both simplifying the interface and allowing more generic containers to be passed. The same is done for `EncodeBase58Check`, where only one interface existed but it's more generic now (e.g. a std::array can be directly passed, as done in the benchmarks).

ACKs for top commit:
  laanwj:
    Code review ACK 356988e

Tree-SHA512: 47cfccdd7f3a2d4694bb8785e6e5fd756daee04ce1652ee59a7822e7e833b4a441ae9362b9bd67ea020d2b5b7d927629c9addb6abaa9881d8564fd3b1257f512

Author: laanwj

src/base58.cpp

@@ -84,21 +84,21 @@ bool DecodeBase58(const char* psz, std::vector<unsigned char>& vch, int max_ret_
     return true;
 }
 
-std::string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend)
+std::string EncodeBase58(Span<const unsigned char> input)
 {
     // Skip & count leading zeroes.
     int zeroes = 0;
     int length = 0;
-    while (pbegin != pend && *pbegin == 0) {
-        pbegin++;
+    while (input.size() > 0 && input[0] == 0) {
+        input = input.subspan(1);
         zeroes++;
     }
     // Allocate enough space in big-endian base58 representation.
-    int size = (pend - pbegin) * 138 / 100 + 1; // log(256) / log(58), rounded up.
+    int size = input.size() * 138 / 100 + 1; // log(256) / log(58), rounded up.
     std::vector<unsigned char> b58(size);
     // Process the bytes.
-    while (pbegin != pend) {
-        int carry = *pbegin;
+    while (input.size() > 0) {
+        int carry = input[0];
         int i = 0;
         // Apply "b58 = b58 * 256 + ch".
         for (std::vector<unsigned char>::reverse_iterator it = b58.rbegin(); (carry != 0 || i < length) && (it != b58.rend()); it++, i++) {
@@ -109,7 +109,7 @@ std::string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend)
 
         assert(carry == 0);
         length = i;
-        pbegin++;
+        input = input.subspan(1);
     }
     // Skip leading zeroes in base58 result.
     std::vector<unsigned char>::iterator it = b58.begin() + (size - length);
@@ -124,11 +124,6 @@ std::string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend)
     return str;
 }
 
-std::string EncodeBase58(const std::vector<unsigned char>& vch)
-{
-    return EncodeBase58(vch.data(), vch.data() + vch.size());
-}
-
 bool DecodeBase58(const std::string& str, std::vector<unsigned char>& vchRet, int max_ret_len)
 {
     if (!ValidAsCString(str)) {
@@ -137,10 +132,10 @@ bool DecodeBase58(const std::string& str, std::vector<unsigned char>& vchRet, in
     return DecodeBase58(str.c_str(), vchRet, max_ret_len);
 }
 
-std::string EncodeBase58Check(const std::vector<unsigned char>& vchIn)
+std::string EncodeBase58Check(Span<const unsigned char> input)
 {
     // add 4-byte hash check to the end
-    std::vector<unsigned char> vch(vchIn);
+    std::vector<unsigned char> vch(input.begin(), input.end());
     uint256 hash = Hash(vch);
     vch.insert(vch.end(), (unsigned char*)&hash, (unsigned char*)&hash + 4);
     return EncodeBase58(vch);

src/base58.h

@@ -15,20 +15,15 @@
 #define BITCOIN_BASE58_H
 
 #include <attributes.h>
+#include <span.h>
 
 #include <string>
 #include <vector>
 
 /**
- * Encode a byte sequence as a base58-encoded string.
- * pbegin and pend cannot be nullptr, unless both are.
+ * Encode a byte span as a base58-encoded string
  */
-std::string EncodeBase58(const unsigned char* pbegin, const unsigned char* pend);
-
-/**
- * Encode a byte vector as a base58-encoded string
- */
-std::string EncodeBase58(const std::vector<unsigned char>& vch);
+std::string EncodeBase58(Span<const unsigned char> input);
 
 /**
  * Decode a base58-encoded string (psz) into a byte vector (vchRet).
@@ -44,9 +39,9 @@ NODISCARD bool DecodeBase58(const char* psz, std::vector<unsigned char>& vchRet,
 NODISCARD bool DecodeBase58(const std::string& str, std::vector<unsigned char>& vchRet, int max_ret_len);
 
 /**
- * Encode a byte vector into a base58-encoded string, including checksum
+ * Encode a byte span into a base58-encoded string, including checksum
  */
-std::string EncodeBase58Check(const std::vector<unsigned char>& vchIn);
+std::string EncodeBase58Check(Span<const unsigned char> input);
 
 /**
  * Decode a base58-encoded string (psz) that includes a checksum into a byte

src/bench/base58.cpp

@@ -20,7 +20,7 @@ static void Base58Encode(benchmark::Bench& bench)
         }
     };
     bench.batch(buff.size()).unit("byte").run([&] {
-        EncodeBase58(buff.data(), buff.data() + buff.size());
+        EncodeBase58(buff);
     });
 }
 
@@ -34,10 +34,8 @@ static void Base58CheckEncode(benchmark::Bench& bench)
             200, 24
         }
     };
-    std::vector<unsigned char> vch;
-    vch.assign(buff.begin(), buff.end());
     bench.batch(buff.size()).unit("byte").run([&] {
-        EncodeBase58Check(vch);
+        EncodeBase58Check(buff);
     });
 }
 

src/qt/guiutil.cpp

@@ -94,7 +94,7 @@ static std::string DummyAddress(const CChainParams &params)
     std::vector<unsigned char> sourcedata = params.Base58Prefix(CChainParams::PUBKEY_ADDRESS);
     sourcedata.insert(sourcedata.end(), dummydata, dummydata + sizeof(dummydata));
     for(int i=0; i<256; ++i) { // Try every trailing byte
-        std::string s = EncodeBase58(sourcedata.data(), sourcedata.data() + sourcedata.size());
+        std::string s = EncodeBase58(sourcedata);
         if (!IsValidDestinationString(s)) {
             return s;
         }

src/test/base58_tests.cpp

@@ -33,7 +33,7 @@ BOOST_AUTO_TEST_CASE(base58_EncodeBase58)
         std::vector<unsigned char> sourcedata = ParseHex(test[0].get_str());
         std::string base58string = test[1].get_str();
         BOOST_CHECK_MESSAGE(
-                    EncodeBase58(sourcedata.data(), sourcedata.data() + sourcedata.size()) == base58string,
+                    EncodeBase58(sourcedata) == base58string,
                     strTest);
     }
 }