Merge bitcoin#30532: refactor: remove deprecated TxidFromString() in …

…favour of transaction_identifier::FromHex()

f553e6d refactor: remove TxidFromString (stickies-v)
285ab50 test: replace WtxidFromString with Wtxid::FromHex (stickies-v)
9a0b2a6 fuzz: increase FromHex() coverage (stickies-v)
526a87b test: add uint256::FromHex unittest coverage (stickies-v)

Pull request description:

  Since bitcoin@fab6ddb, `TxidFromString()` has been deprecated because it is less robust than the `transaction_identifier::FromHex()` introduced in [the same PR](bitcoin#30482). Specifically, it tries to recover from length-mismatches, recover from untrimmed whitespace, 0x-prefix and garbage at the end, instead of simply requiring exactly 64 hex-only characters.

  In this PR, `TxidFromString` is removed completely to clean up the code and prevent further unsafe usage. Unit and fuzz test coverage on `uint256::FromHex()` and functions that wrap it is increased.

  Note: `TxidFromSring` allowed users to prefix strings with "0x", this is no longer allowed for `transaction_identifier::FromHex()`, so a helper function for input validation may prove helpful in the future _(this overlaps with the `uint256::uint256S()` vs `uint256::FromHex()` future cleanup)_. It is not relevant to this PR, though, besides the fact that this unused (except for in tests) functionality is removed.

  The only users of `TxidFromString` are:
  - `test`, where it is straightforward to drop in the new `FromHex()` methods without much further concern
  - `qt` coincontrol. There is no need for input validation here, but txids are not guaranteed to be 64 characters. This is already handled by the existing code, so again, using `FromHex()` here seems quite straightforward.

  Addresses @maflcko's suggestion: bitcoin#30482 (comment)

  Also removes `WtxidFromString()`, which is a test-only helper function.

  ### Testing GUI changes

  To test the GUI coincontrol affected lines, `regtest` is probably the easiest way to quickly get some test coins, you can use e.g.

  ```
  alias cli="./src/bitcoin-cli -regtest"
  cli createwallet "coincontrol"
  # generate 10 spendable outputs on 1 address
  cli generatetoaddress 10 $(cli -rpcwallet=coincontrol getnewaddress)
  # generate 10 spendable outputs on another address
  cli generatetoaddress 10 $(cli -rpcwallet=coincontrol getnewaddress)
  # make previous outputs spendable
  cli generatetoaddress 100 $(cli -rpcwallet=coincontrol getnewaddress)
  ```

ACKs for top commit:
  maflcko:
    re-ACK f553e6d 🔻
  hodlinator:
    ACK f553e6d
  paplorinc:
    ACK f553e6d
  TheCharlatan:
    Nice, ACK f553e6d

Tree-SHA512: c1c7e6ea4cbf05cf660ba178ffc4f35f0328f7aa6ad81872e2462fb91a6a22e4681ff64b3d0202a5a9abcb650c939561585cd309164a69ab6081c0765ee271ef

src/qt/coincontroldialog.cpp

@@ -174,22 +174,17 @@ void CoinControlDialog::showMenu(const QPoint &point)
         contextMenuItem = item;
 
         // disable some items (like Copy Transaction ID, lock, unlock) for tree roots in context menu
-        if (item->data(COLUMN_ADDRESS, TxHashRole).toString().length() == 64) // transaction hash is 64 characters (this means it is a child node, so it is not a parent node in tree mode)
-        {
+        auto txid{Txid::FromHex(item->data(COLUMN_ADDRESS, TxHashRole).toString().toStdString())};
+        if (txid) { // a valid txid means this is a child node, and not a parent node in tree mode
             m_copy_transaction_outpoint_action->setEnabled(true);
-            if (model->wallet().isLockedCoin(COutPoint(TxidFromString(item->data(COLUMN_ADDRESS, TxHashRole).toString().toStdString()), item->data(COLUMN_ADDRESS, VOutRole).toUInt())))
-            {
+            if (model->wallet().isLockedCoin(COutPoint(*txid, item->data(COLUMN_ADDRESS, VOutRole).toUInt()))) {
                 lockAction->setEnabled(false);
                 unlockAction->setEnabled(true);
-            }
-            else
-            {
+            } else {
                 lockAction->setEnabled(true);
                 unlockAction->setEnabled(false);
             }
-        }
-        else // this means click on parent node in tree mode -> disable all
-        {
+        } else { // this means click on parent node in tree mode -> disable all
             m_copy_transaction_outpoint_action->setEnabled(false);
             lockAction->setEnabled(false);
             unlockAction->setEnabled(false);
@@ -240,7 +235,7 @@ void CoinControlDialog::lockCoin()
     if (contextMenuItem->checkState(COLUMN_CHECKBOX) == Qt::Checked)
         contextMenuItem->setCheckState(COLUMN_CHECKBOX, Qt::Unchecked);
 
-    COutPoint outpt(TxidFromString(contextMenuItem->data(COLUMN_ADDRESS, TxHashRole).toString().toStdString()), contextMenuItem->data(COLUMN_ADDRESS, VOutRole).toUInt());
+    COutPoint outpt(Txid::FromHex(contextMenuItem->data(COLUMN_ADDRESS, TxHashRole).toString().toStdString()).value(), contextMenuItem->data(COLUMN_ADDRESS, VOutRole).toUInt());
     model->wallet().lockCoin(outpt, /* write_to_db = */ true);
     contextMenuItem->setDisabled(true);
     contextMenuItem->setIcon(COLUMN_CHECKBOX, platformStyle->SingleColorIcon(":/icons/lock_closed"));
@@ -250,7 +245,7 @@ void CoinControlDialog::lockCoin()
 // context menu action: unlock coin
 void CoinControlDialog::unlockCoin()
 {
-    COutPoint outpt(TxidFromString(contextMenuItem->data(COLUMN_ADDRESS, TxHashRole).toString().toStdString()), contextMenuItem->data(COLUMN_ADDRESS, VOutRole).toUInt());
+    COutPoint outpt(Txid::FromHex(contextMenuItem->data(COLUMN_ADDRESS, TxHashRole).toString().toStdString()).value(), contextMenuItem->data(COLUMN_ADDRESS, VOutRole).toUInt());
     model->wallet().unlockCoin(outpt);
     contextMenuItem->setDisabled(false);
     contextMenuItem->setIcon(COLUMN_CHECKBOX, QIcon());
@@ -340,9 +335,10 @@ void CoinControlDialog::radioListMode(bool checked)
 // checkbox clicked by user
 void CoinControlDialog::viewItemChanged(QTreeWidgetItem* item, int column)
 {
-    if (column == COLUMN_CHECKBOX && item->data(COLUMN_ADDRESS, TxHashRole).toString().length() == 64) // transaction hash is 64 characters (this means it is a child node, so it is not a parent node in tree mode)
-    {
-        COutPoint outpt(TxidFromString(item->data(COLUMN_ADDRESS, TxHashRole).toString().toStdString()), item->data(COLUMN_ADDRESS, VOutRole).toUInt());
+    if (column != COLUMN_CHECKBOX) return;
+    auto txid{Txid::FromHex(item->data(COLUMN_ADDRESS, TxHashRole).toString().toStdString())};
+    if (txid) { // a valid txid means this is a child node, and not a parent node in tree mode
+        COutPoint outpt(*txid, item->data(COLUMN_ADDRESS, VOutRole).toUInt());
 
         if (item->checkState(COLUMN_CHECKBOX) == Qt::Unchecked)
             m_coin_control.UnSelect(outpt);

src/test/bloom_tests.cpp

@@ -138,11 +138,11 @@ BOOST_AUTO_TEST_CASE(bloom_match)
     BOOST_CHECK_MESSAGE(filter.IsRelevantAndUpdate(tx), "Simple Bloom filter didn't match output address");
 
     filter = CBloomFilter(10, 0.000001, 0, BLOOM_UPDATE_ALL);
-    filter.insert(COutPoint(TxidFromString("0x90c122d70786e899529d71dbeba91ba216982fb6ba58f3bdaab65e73b7e9260b"), 0));
+    filter.insert(COutPoint(Txid::FromHex("90c122d70786e899529d71dbeba91ba216982fb6ba58f3bdaab65e73b7e9260b").value(), 0));
     BOOST_CHECK_MESSAGE(filter.IsRelevantAndUpdate(tx), "Simple Bloom filter didn't match COutPoint");
 
     filter = CBloomFilter(10, 0.000001, 0, BLOOM_UPDATE_ALL);
-    COutPoint prevOutPoint(TxidFromString("0x90c122d70786e899529d71dbeba91ba216982fb6ba58f3bdaab65e73b7e9260b"), 0);
+    COutPoint prevOutPoint(Txid::FromHex("90c122d70786e899529d71dbeba91ba216982fb6ba58f3bdaab65e73b7e9260b").value(), 0);
     {
         std::vector<unsigned char> data(32 + sizeof(unsigned int));
         memcpy(data.data(), prevOutPoint.hash.begin(), 32);
@@ -160,11 +160,11 @@ BOOST_AUTO_TEST_CASE(bloom_match)
     BOOST_CHECK_MESSAGE(!filter.IsRelevantAndUpdate(tx), "Simple Bloom filter matched random address");
 
     filter = CBloomFilter(10, 0.000001, 0, BLOOM_UPDATE_ALL);
-    filter.insert(COutPoint(TxidFromString("0x90c122d70786e899529d71dbeba91ba216982fb6ba58f3bdaab65e73b7e9260b"), 1));
+    filter.insert(COutPoint(Txid::FromHex("90c122d70786e899529d71dbeba91ba216982fb6ba58f3bdaab65e73b7e9260b").value(), 1));
     BOOST_CHECK_MESSAGE(!filter.IsRelevantAndUpdate(tx), "Simple Bloom filter matched COutPoint for an output we didn't care about");
 
     filter = CBloomFilter(10, 0.000001, 0, BLOOM_UPDATE_ALL);
-    filter.insert(COutPoint(TxidFromString("0x000000d70786e899529d71dbeba91ba216982fb6ba58f3bdaab65e73b7e9260b"), 0));
+    filter.insert(COutPoint(Txid::FromHex("000000d70786e899529d71dbeba91ba216982fb6ba58f3bdaab65e73b7e9260b").value(), 0));
     BOOST_CHECK_MESSAGE(!filter.IsRelevantAndUpdate(tx), "Simple Bloom filter matched COutPoint for an output we didn't care about");
 }
 
@@ -426,9 +426,9 @@ BOOST_AUTO_TEST_CASE(merkle_block_4_test_p2pubkey_only)
     BOOST_CHECK(merkleBlock.header.GetHash() == block.GetHash());
 
     // We should match the generation outpoint
-    BOOST_CHECK(filter.contains(COutPoint(TxidFromString("0x147caa76786596590baa4e98f5d9f48b86c7765e489f7a6ff3360fe5c674360b"), 0)));
+    BOOST_CHECK(filter.contains(COutPoint(Txid::FromHex("147caa76786596590baa4e98f5d9f48b86c7765e489f7a6ff3360fe5c674360b").value(), 0)));
     // ... but not the 4th transaction's output (its not pay-2-pubkey)
-    BOOST_CHECK(!filter.contains(COutPoint(TxidFromString("0x02981fa052f0481dbc5868f4fc2166035a10f27a03cfd2de67326471df5bc041"), 0)));
+    BOOST_CHECK(!filter.contains(COutPoint(Txid::FromHex("02981fa052f0481dbc5868f4fc2166035a10f27a03cfd2de67326471df5bc041").value(), 0)));
 }
 
 BOOST_AUTO_TEST_CASE(merkle_block_4_test_update_none)
@@ -451,8 +451,8 @@ BOOST_AUTO_TEST_CASE(merkle_block_4_test_update_none)
     BOOST_CHECK(merkleBlock.header.GetHash() == block.GetHash());
 
     // We shouldn't match any outpoints (UPDATE_NONE)
-    BOOST_CHECK(!filter.contains(COutPoint(TxidFromString("0x147caa76786596590baa4e98f5d9f48b86c7765e489f7a6ff3360fe5c674360b"), 0)));
-    BOOST_CHECK(!filter.contains(COutPoint(TxidFromString("0x02981fa052f0481dbc5868f4fc2166035a10f27a03cfd2de67326471df5bc041"), 0)));
+    BOOST_CHECK(!filter.contains(COutPoint(Txid::FromHex("147caa76786596590baa4e98f5d9f48b86c7765e489f7a6ff3360fe5c674360b").value(), 0)));
+    BOOST_CHECK(!filter.contains(COutPoint(Txid::FromHex("02981fa052f0481dbc5868f4fc2166035a10f27a03cfd2de67326471df5bc041").value(), 0)));
 }
 
 static std::vector<unsigned char> RandomData()

src/test/fuzz/hex.cpp

@@ -10,6 +10,7 @@
 #include <uint256.h>
 #include <univalue.h>
 #include <util/strencodings.h>
+#include <util/transaction_identifier.h>
 
 #include <cassert>
 #include <cstdint>
@@ -27,7 +28,11 @@ FUZZ_TARGET(hex)
         assert(ToLower(random_hex_string) == hex_data);
     }
     (void)IsHexNumber(random_hex_string);
-    (void)uint256::FromHex(random_hex_string);
+    if (uint256::FromHex(random_hex_string)) {
+        assert(random_hex_string.length() == 64);
+        assert(Txid::FromHex(random_hex_string));
+        assert(Wtxid::FromHex(random_hex_string));
+    }
     (void)uint256S(random_hex_string);
     try {
         (void)HexToPubKey(random_hex_string);

src/test/merkleblock_tests.cpp

@@ -24,10 +24,10 @@ BOOST_AUTO_TEST_CASE(merkleblock_construct_from_txids_found)
     std::set<Txid> txids;
 
     // Last txn in block.
-    Txid txhash1{TxidFromString("0x74d681e0e03bafa802c8aa084379aa98d9fcd632ddc2ed9782b586ec87451f20")};
+    Txid txhash1{Txid::FromHex("74d681e0e03bafa802c8aa084379aa98d9fcd632ddc2ed9782b586ec87451f20").value()};
 
     // Second txn in block.
-    Txid txhash2{TxidFromString("0xf9fc751cb7dc372406a9f8d738d5e6f8f63bab71986a39cf36ee70ee17036d07")};
+    Txid txhash2{Txid::FromHex("f9fc751cb7dc372406a9f8d738d5e6f8f63bab71986a39cf36ee70ee17036d07").value()};
 
     txids.insert(txhash1);
     txids.insert(txhash2);
@@ -63,7 +63,7 @@ BOOST_AUTO_TEST_CASE(merkleblock_construct_from_txids_not_found)
     CBlock block = getBlock13b8a();
 
     std::set<Txid> txids2;
-    txids2.insert(TxidFromString("0xc0ffee00003bafa802c8aa084379aa98d9fcd632ddc2ed9782b586ec87451f20"));
+    txids2.insert(Txid::FromHex("c0ffee00003bafa802c8aa084379aa98d9fcd632ddc2ed9782b586ec87451f20").value());
     CMerkleBlock merkleBlock(block, txids2);
 
     BOOST_CHECK_EQUAL(merkleBlock.header.GetHash().GetHex(), block.GetHash().GetHex());

src/test/transaction_tests.cpp

@@ -223,7 +223,7 @@ BOOST_AUTO_TEST_CASE(tx_valid)
                     fValid = false;
                     break;
                 }
-                COutPoint outpoint{TxidFromString(vinput[0].get_str()), uint32_t(vinput[1].getInt<int>())};
+                COutPoint outpoint{Txid::FromHex(vinput[0].get_str()).value(), uint32_t(vinput[1].getInt<int>())};
                 mapprevOutScriptPubKeys[outpoint] = ParseScript(vinput[2].get_str());
                 if (vinput.size() >= 4)
                 {
@@ -311,7 +311,7 @@ BOOST_AUTO_TEST_CASE(tx_invalid)
                     fValid = false;
                     break;
                 }
-                COutPoint outpoint{TxidFromString(vinput[0].get_str()), uint32_t(vinput[1].getInt<int>())};
+                COutPoint outpoint{Txid::FromHex(vinput[0].get_str()).value(), uint32_t(vinput[1].getInt<int>())};
                 mapprevOutScriptPubKeys[outpoint] = ParseScript(vinput[2].get_str());
                 if (vinput.size() >= 4)
                 {
@@ -542,7 +542,7 @@ BOOST_AUTO_TEST_CASE(test_big_witness_transaction)
     // create a big transaction of 4500 inputs signed by the same key
     for(uint32_t ij = 0; ij < 4500; ij++) {
         uint32_t i = mtx.vin.size();
-        COutPoint outpoint(TxidFromString("0000000000000000000000000000000000000000000000000000000000000100"), i);
+        COutPoint outpoint(Txid::FromHex("0000000000000000000000000000000000000000000000000000000000000100").value(), i);
 
         mtx.vin.resize(mtx.vin.size() + 1);
         mtx.vin[i].prevout = outpoint;
@@ -1028,12 +1028,4 @@ BOOST_AUTO_TEST_CASE(test_IsStandard)
     }
 }
 
-BOOST_AUTO_TEST_CASE(test_TxidFromString)
-{
-    // Make sure TxidFromString respects string_view length and stops reading at
-    // end of the substring.
-    BOOST_CHECK_EQUAL(TxidFromString(std::string_view("ABCD1234", 4)).ToString(),
-        "000000000000000000000000000000000000000000000000000000000000abcd");
-}
-
 BOOST_AUTO_TEST_SUITE_END()

src/test/txpackage_tests.cpp

@@ -43,13 +43,6 @@ inline CTransactionRef create_placeholder_tx(size_t num_inputs, size_t num_outpu
     }
     return MakeTransactionRef(mtx);
 }
-
-// Create a Wtxid from a hex string
-inline Wtxid WtxidFromString(std::string_view str)
-{
-    return Wtxid::FromUint256(uint256S(str));
-}
-
 BOOST_FIXTURE_TEST_CASE(package_hash_tests, TestChain100Setup)
 {
     // Random real segwit transaction
@@ -74,9 +67,9 @@ BOOST_FIXTURE_TEST_CASE(package_hash_tests, TestChain100Setup)
     CTransactionRef ptx_3{MakeTransactionRef(tx_3)};
 
     // It's easy to see that wtxids are sorted in lexicographical order:
-    Wtxid wtxid_1{WtxidFromString("0x85cd1a31eb38f74ed5742ec9cb546712ab5aaf747de28a9168b53e846cbda17f")};
-    Wtxid wtxid_2{WtxidFromString("0xb4749f017444b051c44dfd2720e88f314ff94f3dd6d56d40ef65854fcd7fff6b")};
-    Wtxid wtxid_3{WtxidFromString("0xe065bac15f62bb4e761d761db928ddee65a47296b2b776785abb912cdec474e3")};
+    Wtxid wtxid_1{Wtxid::FromHex("85cd1a31eb38f74ed5742ec9cb546712ab5aaf747de28a9168b53e846cbda17f").value()};
+    Wtxid wtxid_2{Wtxid::FromHex("b4749f017444b051c44dfd2720e88f314ff94f3dd6d56d40ef65854fcd7fff6b").value()};
+    Wtxid wtxid_3{Wtxid::FromHex("e065bac15f62bb4e761d761db928ddee65a47296b2b776785abb912cdec474e3").value()};
     BOOST_CHECK_EQUAL(tx_1.GetWitnessHash(), wtxid_1);
     BOOST_CHECK_EQUAL(tx_2.GetWitnessHash(), wtxid_2);
     BOOST_CHECK_EQUAL(tx_3.GetWitnessHash(), wtxid_3);
@@ -85,9 +78,9 @@ BOOST_FIXTURE_TEST_CASE(package_hash_tests, TestChain100Setup)
     BOOST_CHECK(wtxid_2.GetHex() < wtxid_3.GetHex());
 
     // The txids are not (we want to test that sorting and hashing use wtxid, not txid):
-    Txid txid_1{TxidFromString("0xbd0f71c1d5e50589063e134fad22053cdae5ab2320db5bf5e540198b0b5a4e69")};
-    Txid txid_2{TxidFromString("0xb4749f017444b051c44dfd2720e88f314ff94f3dd6d56d40ef65854fcd7fff6b")};
-    Txid txid_3{TxidFromString("0xee707be5201160e32c4fc715bec227d1aeea5940fb4295605e7373edce3b1a93")};
+    Txid txid_1{Txid::FromHex("bd0f71c1d5e50589063e134fad22053cdae5ab2320db5bf5e540198b0b5a4e69").value()};
+    Txid txid_2{Txid::FromHex("b4749f017444b051c44dfd2720e88f314ff94f3dd6d56d40ef65854fcd7fff6b").value()};
+    Txid txid_3{Txid::FromHex("ee707be5201160e32c4fc715bec227d1aeea5940fb4295605e7373edce3b1a93").value()};
     BOOST_CHECK_EQUAL(tx_1.GetHash(), txid_1);
     BOOST_CHECK_EQUAL(tx_2.GetHash(), txid_2);
     BOOST_CHECK_EQUAL(tx_3.GetHash(), txid_3);

src/test/uint256_tests.cpp

@@ -6,12 +6,15 @@
 #include <streams.h>
 #include <test/util/setup_common.h>
 #include <uint256.h>
+#include <util/strencodings.h>
+#include <util/transaction_identifier.h>
 
 #include <boost/test/unit_test.hpp>
 
 #include <iomanip>
 #include <sstream>
 #include <string>
+#include <string_view>
 #include <vector>
 
 BOOST_AUTO_TEST_SUITE(uint256_tests)
@@ -330,6 +333,59 @@ BOOST_AUTO_TEST_CASE(parse)
     }
 }
 
+/**
+ * Implemented as a templated function so it can be reused by other classes that have a FromHex()
+ * method that wraps base_blob::FromHex(), such as transaction_identifier::FromHex().
+ */
+template <typename T>
+void TestFromHex()
+{
+    constexpr unsigned int num_chars{T::size() * 2};
+    static_assert(num_chars <= 64); // this test needs to be modified to allow for more than 64 hex chars
+    const std::string valid_64char_input{"0123456789abcdef0123456789ABCDEF0123456789abcdef0123456789ABCDEF"};
+    const auto valid_input{valid_64char_input.substr(0, num_chars)};
+    {
+        // check that lower and upper case hex characters are accepted
+        auto valid_result{T::FromHex(valid_input)};
+        BOOST_REQUIRE(valid_result);
+        BOOST_CHECK_EQUAL(valid_result->ToString(), ToLower(valid_input));
+    }
+    {
+        // check that only strings of size num_chars are accepted
+        BOOST_CHECK(!T::FromHex(""));
+        BOOST_CHECK(!T::FromHex("0"));
+        BOOST_CHECK(!T::FromHex(valid_input.substr(0, num_chars / 2)));
+        BOOST_CHECK(!T::FromHex(valid_input.substr(0, num_chars - 1)));
+        BOOST_CHECK(!T::FromHex(valid_input + "0"));
+    }
+    {
+        // check that non-hex characters are not accepted
+        std::string invalid_chars{R"( !"#$%&'()*+,-./:;<=>?@GHIJKLMNOPQRSTUVWXYZ[\]^_`ghijklmnopqrstuvwxyz{|}~)"};
+        for (auto c : invalid_chars) {
+            BOOST_CHECK(!T::FromHex(valid_input.substr(0, num_chars - 1) + c));
+        }
+        // 0x prefixes are invalid
+        std::string invalid_prefix{"0x" + valid_input};
+        BOOST_CHECK(!T::FromHex(std::string_view(invalid_prefix.data(), num_chars)));
+        BOOST_CHECK(!T::FromHex(invalid_prefix));
+    }
+    {
+        // check that string_view length is respected
+        std::string chars_68{valid_64char_input + "0123"};
+        BOOST_CHECK_EQUAL(T::FromHex(std::string_view(chars_68.data(), num_chars)).value().ToString(), ToLower(valid_input));
+        BOOST_CHECK(!T::FromHex(std::string_view(chars_68.data(), num_chars - 1))); // too short
+        BOOST_CHECK(!T::FromHex(std::string_view(chars_68.data(), num_chars + 1))); // too long
+    }
+}
+
+BOOST_AUTO_TEST_CASE(from_hex)
+{
+    TestFromHex<uint160>();
+    TestFromHex<uint256>();
+    TestFromHex<Txid>();
+    TestFromHex<Wtxid>();
+}
+
 BOOST_AUTO_TEST_CASE( check_ONE )
 {
     uint256 one = uint256S("0000000000000000000000000000000000000000000000000000000000000001");

src/util/transaction_identifier.h

@@ -72,10 +72,4 @@ using Txid = transaction_identifier<false>;
 /** Wtxid commits to all transaction fields including the witness. */
 using Wtxid = transaction_identifier<true>;
 
-/** DEPRECATED due to missing length-check and hex-check, please use the safer FromHex, or FromUint256 */
-inline Txid TxidFromString(std::string_view str)
-{
-    return Txid::FromUint256(uint256S(str));
-}
-
 #endif // BITCOIN_UTIL_TRANSACTION_IDENTIFIER_H