YQL-16239 Move purecalc to public

1 files changed, 54 insertions, 0 deletions

diff --git a/library/cpp/ipreg/split.cpp b/library/cpp/ipreg/split.cpp
new file mode 100644
index 00000000000..19b7b85d510
--- /dev/null
+++ b/library/cpp/ipreg/split.cpp
@@ -0,0 +1,54 @@
+#include "split.h"
+
+#include <util/generic/list.h>
+#include <util/generic/vector.h>
+
+namespace NIPREG {
+
+void SplitIPREG(TReader &reader, std::function<void(const TAddress& first, const TAddress& last, const TVector<TString>& data)>&& proc) {
+    TList<TGenericEntry> prevEntries;
+
+    bool end;
+    do {
+        end = !reader.Next();
+
+        while (!prevEntries.empty() && (end || prevEntries.front().First < reader.Get().First)) {
+            // find smallest common range to process
+            TAddress first = prevEntries.front().First;
+            TAddress last = end ? TAddress::Highest() : reader.Get().First.Prev();
+
+            for (const auto& entry: prevEntries)
+                last = Min(last, entry.Last);
+
+            // extract data for the range
+            TVector<TString> strings;
+            auto item = prevEntries.begin();
+            while (item != prevEntries.end()) {
+                Y_ASSERT(item->First == first);
+                strings.push_back(item->Data);
+
+                if (item->Last == last) {
+                    // item completely processed, remove
+                    auto victim = item;
+                    item++;
+                    prevEntries.erase(victim);
+                } else {
+                    // item still have part of range left, update it
+                    item->First = last.Next();
+                    item++;
+                }
+            }
+
+            proc(first, last, strings);
+        }
+
+        if (!end) {
+            if (!prevEntries.empty()) {
+                Y_ASSERT(prevEntries.front().First == reader.Get().First);
+            }
+            prevEntries.push_back(reader.Get());
+        }
+    } while (!end);
+}
+
+}