refactored hassing task

Signed-off-by: Trial97 <alexandru.tripon97@gmail.com>

libraries/murmur2/src/MurmurHash2.cpp

@@ -8,14 +8,14 @@
 
 #include "MurmurHash2.h"
 
-//-----------------------------------------------------------------------------
+namespace Murmur2 {
 
 // 'm' and 'r' are mixing constants generated offline.
 // They're not really 'magic', they just happen to work well.
 const uint32_t m = 0x5bd1e995;
 const int r = 24;
 
-uint32_t MurmurHash2(std::ifstream&& file_stream, std::size_t buffer_size, std::function<bool(char)> filter_out)
+uint32_t hash(Reader* file_stream, std::size_t buffer_size, std::function<bool(char)> filter_out)
 {
     auto* buffer = new char[buffer_size];
     char data[4];
@@ -26,24 +26,21 @@ uint32_t MurmurHash2(std::ifstream&& file_stream, std::size_t buffer_size, std::
     // We need the size without the filtered out characters before actually calculating the hash,
     // to setup the initial value for the hash.
     do {
-        file_stream.read(buffer, buffer_size);
-        read = file_stream.gcount();
+        read = file_stream->read(buffer, buffer_size);
         for (int i = 0; i < read; i++) {
             if (!filter_out(buffer[i]))
                 size += 1;
         }
-    } while (!file_stream.eof());
+    } while (!file_stream->eof());
 
-    file_stream.clear();
-    file_stream.seekg(0, file_stream.beg);
+    file_stream->goToBegining();
 
     int index = 0;
 
     // This forces a seed of 1.
     IncrementalHashInfo info{ (uint32_t)1 ^ size, (uint32_t)size };
     do {
-        file_stream.read(buffer, buffer_size);
-        read = file_stream.gcount();
+        read = file_stream->read(buffer, buffer_size);
         for (int i = 0; i < read; i++) {
             char c = buffer[i];
 
@@ -57,14 +54,13 @@ uint32_t MurmurHash2(std::ifstream&& file_stream, std::size_t buffer_size, std::
             if (index == 0)
                 FourBytes_MurmurHash2(reinterpret_cast<unsigned char*>(&data), info);
         }
-    } while (!file_stream.eof());
+    } while (!file_stream->eof());
 
     // Do one last bit shuffle in the hash
     FourBytes_MurmurHash2(reinterpret_cast<unsigned char*>(&data), info);
 
     delete[] buffer;
 
-    file_stream.close();
     return info.h;
 }
 
@@ -109,4 +105,4 @@ void FourBytes_MurmurHash2(const unsigned char* data, IncrementalHashInfo& prev)
     }
 }
 
-//-----------------------------------------------------------------------------
+}  // namespace Murmur2

libraries/murmur2/src/MurmurHash2.h

@@ -9,17 +9,23 @@
 #pragma once
 
 #include <cstdint>
-#include <fstream>
-
 #include <functional>
 
-//-----------------------------------------------------------------------------
+namespace Murmur2 {
 
 #define KiB 1024
 #define MiB 1024 * KiB
 
-uint32_t MurmurHash2(
-    std::ifstream&& file_stream,
+class Reader {
+   public:
+    virtual ~Reader() = default;
+    virtual int read(char* s, int n) = 0;
+    virtual bool eof() = 0;
+    virtual void goToBegining() = 0;
+};
+
+uint32_t hash(
+    Reader* file_stream,
     std::size_t buffer_size = 4 * MiB,
     std::function<bool(char)> filter_out = [](char) { return false; });
 
@@ -29,5 +35,4 @@ struct IncrementalHashInfo {
 };
 
 void FourBytes_MurmurHash2(const unsigned char* data, IncrementalHashInfo& prev);
-
-//-----------------------------------------------------------------------------
+}  // namespace Murmur2