From ba6ff9a6f70139594362b4b4a6b816707bb165c8 Mon Sep 17 00:00:00 2001
From: Jim Posen <jim.posen@gmail.com>
Date: Mon, 27 Aug 2018 15:42:35 -0700
Subject: [PATCH] blockfilter: Functions to translate filter types to/from
 names.

---
 src/blockfilter.cpp            | 21 +++++++++++++++++++++
 src/blockfilter.h              |  7 +++++++
 src/test/blockfilter_tests.cpp | 12 ++++++++++++
 3 files changed, 40 insertions(+)

diff --git a/src/blockfilter.cpp b/src/blockfilter.cpp
index e15213c552e..b96956212bb 100644
--- a/src/blockfilter.cpp
+++ b/src/blockfilter.cpp
@@ -15,6 +15,10 @@ static constexpr int GCS_SER_TYPE = SER_NETWORK;
 /// Protocol version used to serialize parameters in GCS filter encoding.
 static constexpr int GCS_SER_VERSION = 0;
 
+static const std::map<BlockFilterType, std::string> g_filter_types = {
+    {BlockFilterType::BASIC, "basic"},
+};
+
 template <typename OStream>
 static void GolombRiceEncode(BitStreamWriter<OStream>& bitwriter, uint8_t P, uint64_t x)
 {
@@ -197,6 +201,23 @@ bool GCSFilter::MatchAny(const ElementSet& elements) const
     return MatchInternal(queries.data(), queries.size());
 }
 
+const std::string& BlockFilterTypeName(BlockFilterType filter_type)
+{
+    static std::string unknown_retval = "";
+    auto it = g_filter_types.find(filter_type);
+    return it != g_filter_types.end() ? it->second : unknown_retval;
+}
+
+bool BlockFilterTypeByName(const std::string& name, BlockFilterType& filter_type) {
+    for (const auto& entry : g_filter_types) {
+        if (entry.second == name) {
+            filter_type = entry.first;
+            return true;
+        }
+    }
+    return false;
+}
+
 static GCSFilter::ElementSet BasicFilterElements(const CBlock& block,
                                                  const CBlockUndo& block_undo)
 {
diff --git a/src/blockfilter.h b/src/blockfilter.h
index e5e087ed5a3..7a219ff22b8 100644
--- a/src/blockfilter.h
+++ b/src/blockfilter.h
@@ -6,6 +6,7 @@
 #define BITCOIN_BLOCKFILTER_H
 
 #include <stdint.h>
+#include <string>
 #include <unordered_set>
 #include <vector>
 
@@ -89,6 +90,12 @@ enum class BlockFilterType : uint8_t
     INVALID = 255,
 };
 
+/** Get the human-readable name for a filter type. Returns empty string for unknown types. */
+const std::string& BlockFilterTypeName(BlockFilterType filter_type);
+
+/** Find a filter type by its human-readable name. */
+bool BlockFilterTypeByName(const std::string& name, BlockFilterType& filter_type);
+
 /**
  * Complete block filter struct as defined in BIP 157. Serialization matches
  * payload of "cfilter" messages.
diff --git a/src/test/blockfilter_tests.cpp b/src/test/blockfilter_tests.cpp
index cd0c36d802c..92f9de78e7d 100644
--- a/src/test/blockfilter_tests.cpp
+++ b/src/test/blockfilter_tests.cpp
@@ -174,4 +174,16 @@ BOOST_AUTO_TEST_CASE(blockfilters_json_test)
     }
 }
 
+BOOST_AUTO_TEST_CASE(blockfilter_type_names)
+{
+    BOOST_CHECK_EQUAL(BlockFilterTypeName(BlockFilterType::BASIC), "basic");
+    BOOST_CHECK_EQUAL(BlockFilterTypeName(static_cast<BlockFilterType>(255)), "");
+
+    BlockFilterType filter_type;
+    BOOST_CHECK(BlockFilterTypeByName("basic", filter_type));
+    BOOST_CHECK_EQUAL(filter_type, BlockFilterType::BASIC);
+
+    BOOST_CHECK(!BlockFilterTypeByName("unknown", filter_type));
+}
+
 BOOST_AUTO_TEST_SUITE_END()