From c1855f6052aca806fdb51be01b30dfeee8b55f40 Mon Sep 17 00:00:00 2001
From: Jim Posen <jimpo@coinbase.com>
Date: Tue, 23 Jan 2018 17:25:30 -0800
Subject: blockfilter: Construction of basic block filters.

---
 src/blockfilter.cpp | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

(limited to 'src/blockfilter.cpp')

diff --git a/src/blockfilter.cpp b/src/blockfilter.cpp
index 52d8f8c296..1119b54901 100644
--- a/src/blockfilter.cpp
+++ b/src/blockfilter.cpp
@@ -4,6 +4,8 @@
 
 #include <blockfilter.h>
 #include <hash.h>
+#include <primitives/transaction.h>
+#include <script/script.h>
 #include <streams.h>
 
 /// SerType used to serialize parameters in GCS filter encoding.
@@ -193,3 +195,41 @@ bool GCSFilter::MatchAny(const ElementSet& elements) const
     const std::vector<uint64_t> queries = BuildHashedSet(elements);
     return MatchInternal(queries.data(), queries.size());
 }
+
+static GCSFilter::ElementSet BasicFilterElements(const CBlock& block,
+                                                 const CBlockUndo& block_undo)
+{
+    GCSFilter::ElementSet elements;
+
+    for (const CTransactionRef& tx : block.vtx) {
+        for (const CTxOut& txout : tx->vout) {
+            const CScript& script = txout.scriptPubKey;
+            if (script[0] == OP_RETURN) continue;
+            elements.emplace(script.begin(), script.end());
+        }
+    }
+
+    for (const CTxUndo& tx_undo : block_undo.vtxundo) {
+        for (const Coin& prevout : tx_undo.vprevout) {
+            const CScript& script = prevout.out.scriptPubKey;
+            elements.emplace(script.begin(), script.end());
+        }
+    }
+
+    return elements;
+}
+
+BlockFilter::BlockFilter(BlockFilterType filter_type, const CBlock& block, const CBlockUndo& block_undo)
+    : m_filter_type(filter_type), m_block_hash(block.GetHash())
+{
+    switch (m_filter_type) {
+    case BlockFilterType::BASIC:
+        m_filter = GCSFilter(m_block_hash.GetUint64(0), m_block_hash.GetUint64(1),
+                             BASIC_FILTER_P, BASIC_FILTER_M,
+                             BasicFilterElements(block, block_undo));
+        break;
+
+    default:
+        throw std::invalid_argument("unknown filter_type");
+    }
+}
-- 
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