build: add libbitcoinconsensus files and hook up the lib build

Credit BlueMatt for libbitcoinsonsensus.h/cpp

1 files changed, 91 insertions, 0 deletions

diff --git a/src/script/bitcoinconsensus.cpp b/src/script/bitcoinconsensus.cpp
new file mode 100644
index 0000000000..4faa760ad7
--- /dev/null
+++ b/src/script/bitcoinconsensus.cpp
@@ -0,0 +1,91 @@
+// Copyright (c) 2009-2010 Satoshi Nakamoto
+// Copyright (c) 2009-2014 The Bitcoin developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "bitcoinconsensus.h"
+
+#include "core/transaction.h"
+#include "script/interpreter.h"
+#include "version.h"
+
+namespace {
+
+/** A class that deserializes a single CTransaction one time. */
+class TxInputStream
+{
+public:
+    TxInputStream(int nTypeIn, int nVersionIn, const unsigned char *txTo, size_t txToLen) :
+    m_type(nTypeIn),
+    m_version(nVersionIn),
+    m_data(txTo),
+    m_remaining(txToLen)
+    {}
+
+    TxInputStream& read(char* pch, size_t nSize)
+    {
+        if (nSize > m_remaining)
+            throw std::ios_base::failure(std::string(__func__) + ": end of data");
+
+        if (pch == NULL)
+            throw std::ios_base::failure(std::string(__func__) + ": bad destination buffer");
+
+        if (m_data == NULL)
+            throw std::ios_base::failure(std::string(__func__) + ": bad source buffer");
+
+        memcpy(pch, m_data, nSize);
+        m_remaining -= nSize;
+        m_data += nSize;
+        return *this;
+    }
+
+    template<typename T>
+    TxInputStream& operator>>(T& obj)
+    {
+        ::Unserialize(*this, obj, m_type, m_version);
+        return *this;
+    }
+
+private:
+    const int m_type;
+    const int m_version;
+    const unsigned char* m_data;
+    size_t m_remaining;
+};
+
+inline int set_error(bitcoinconsensus_error* ret, bitcoinconsensus_error serror)
+{
+    if (ret)
+        *ret = serror;
+    return 0;
+}
+
+} // anon namespace
+
+int bitcoinconsensus_verify_script(const unsigned char *scriptPubKey, unsigned int scriptPubKeyLen,
+                                    const unsigned char *txTo        , unsigned int txToLen,
+                                    unsigned int nIn, unsigned int flags, bitcoinconsensus_error* err)
+{
+    try {
+        TxInputStream stream(SER_NETWORK, PROTOCOL_VERSION, txTo, txToLen);
+        CTransaction tx;
+        stream >> tx;
+        if (nIn >= tx.vin.size())
+            return set_error(err, bitcoinconsensus_ERR_TX_INDEX);
+        if (tx.GetSerializeSize(SER_NETWORK, PROTOCOL_VERSION) != txToLen)
+            return set_error(err, bitcoinconsensus_ERR_TX_SIZE_MISMATCH);
+
+         // Regardless of the verification result, the tx did not error.
+         set_error(err, bitcoinconsensus_ERR_OK);
+
+        return VerifyScript(tx.vin[nIn].scriptSig, CScript(scriptPubKey, scriptPubKey + scriptPubKeyLen), flags, SignatureChecker(tx, nIn), NULL);
+    } catch (std::exception &e) {
+        return set_error(err, bitcoinconsensus_ERR_TX_DESERIALIZE); // Error deserializing
+    }
+}
+
+unsigned int bitcoinconsensus_version()
+{
+    // Just use the API version for now
+    return BITCOINCONSENSUS_API_VER;
+}