main: start of address index

Adds a configuration option for addressindex to search for txids by address. Includes
an additional rpc method for getting the txids for an address.

src/txdb.cpp

@@ -21,6 +21,7 @@ using namespace std;
 static const char DB_COINS = 'c';
 static const char DB_BLOCK_FILES = 'f';
 static const char DB_TXINDEX = 't';
+static const char DB_ADDRESSINDEX = 'a';
 static const char DB_BLOCK_INDEX = 'b';
 
 static const char DB_BEST_BLOCK = 'B';
@@ -163,6 +164,38 @@ bool CBlockTreeDB::WriteTxIndex(const std::vector<std::pair<uint256, CDiskTxPos>
     return WriteBatch(batch);
 }
 
+bool CBlockTreeDB::WriteAddressIndex(const std::vector<std::pair<CAddressIndexKey, CAmount > >&vect) {
+    CDBBatch batch(&GetObfuscateKey());
+    for (std::vector<std::pair<CAddressIndexKey, CAmount> >::const_iterator it=vect.begin(); it!=vect.end(); it++)
+	batch.Write(make_pair(DB_ADDRESSINDEX, it->first), it->second);
+    return WriteBatch(batch);
+}
+
+bool CBlockTreeDB::ReadAddressIndex(uint160 addressHash, int type, std::vector<std::pair<CAddressIndexKey, CAmount> > &addressIndex) {
+
+    boost::scoped_ptr<CDBIterator> pcursor(NewIterator());
+
+    pcursor->Seek(make_pair(DB_ADDRESSINDEX, addressHash)); //TODO include type
+
+    while (pcursor->Valid()) {
+        boost::this_thread::interruption_point();
+        std::pair<char,CAddressIndexKey> key;
+        if (pcursor->GetKey(key) && key.first == DB_ADDRESSINDEX && key.second.hashBytes == addressHash) {
+            CAmount nValue;
+            if (pcursor->GetValue(nValue)) {
+                addressIndex.push_back(make_pair(key.second, nValue));
+                pcursor->Next();
+            } else {
+                return error("failed to get address index value");
+            }
+        } else {
+            break;
+        }
+    }
+
+    return true;
+}
+
 bool CBlockTreeDB::WriteFlag(const std::string &name, bool fValue) {
     return Write(std::make_pair(DB_FLAG, name), fValue ? '1' : '0');
 }