Add missing Stream.hpp

include/bolt/Stream.hpp

@@ -0,0 +1,76 @@
+
+#pragma once
+
+#include <cstddef>
+#include <deque>
+
+namespace bolt {
+
+  template<typename T>
+  class Stream {
+  public:
+
+    virtual T get() = 0; 
+    virtual T peek(std::size_t Offset = 0) = 0;
+
+    virtual ~Stream() {}
+
+  };
+
+  template<typename ContainerT, typename T = typename ContainerT::value_type>
+  class VectorStream : public Stream<T> {
+  public:
+
+    using value_type = T;
+
+    ContainerT& Data;
+    value_type Sentry;
+    std::size_t Offset;
+
+    VectorStream(ContainerT& Data, value_type Sentry, std::size_t Offset = 0):
+      Data(Data), Sentry(Sentry), Offset(Offset) {}
+
+    value_type get() override {
+      return Offset < Data.size() ? Data[Offset++] : Sentry;
+    }
+
+    value_type peek(std::size_t Offset2) override {
+      auto I = Offset + Offset2;
+      return I < Data.size() ? Data[I] : Sentry;
+    }
+
+  };
+
+  template<typename T>
+  class BufferedStream : public Stream<T> {
+
+    std::deque<T> Buffer;
+
+  protected:
+
+    virtual T read() = 0;
+
+  public:
+
+    using value_type = T;
+
+    value_type get() override {
+      if (Buffer.empty()) {
+        return read();
+      } else {
+        auto Keep = Buffer.front();
+        Buffer.pop_front();
+        return Keep;
+      }
+    }
+
+    value_type peek(std::size_t Offset = 0) override {
+      while (Buffer.size() <= Offset) {
+        Buffer.push_back(read());
+      }
+      return Buffer[Offset];
+    }
+
+  };
+
+}