Restoring authorship annotation for <iddqd@yandex-team.ru>. Commit 1 of 2.

16 files changed, 206 insertions, 206 deletions

diff --git a/util/stream/buffer.cpp b/util/stream/buffer.cpp
index 2facece4ea..bc2159dff8 100644
--- a/util/stream/buffer.cpp
+++ b/util/stream/buffer.cpp
@@ -113,8 +113,8 @@ size_t TBufferInput::DoNext(const void** ptr, size_t len) {
     Readed_ += len;
     return len;
 }
-
-void TBufferInput::DoUndo(size_t len) {
-    Y_VERIFY(len <= Readed_);
-    Readed_ -= len;
-}
+ 
+void TBufferInput::DoUndo(size_t len) { 
+    Y_VERIFY(len <= Readed_); 
+    Readed_ -= len; 
+} 
diff --git a/util/stream/buffer.h b/util/stream/buffer.h
index 9dc99dbe49..c77960bcb6 100644
--- a/util/stream/buffer.h
+++ b/util/stream/buffer.h
@@ -77,7 +77,7 @@ public:
 
 protected:
     size_t DoNext(const void** ptr, size_t len) override;
-    void DoUndo(size_t len) override;
+    void DoUndo(size_t len) override; 
 
 private:
     const TBuffer& Buf_;
diff --git a/util/stream/buffered.cpp b/util/stream/buffered.cpp
index a00e592e1c..de4ec8c756 100644
--- a/util/stream/buffered.cpp
+++ b/util/stream/buffered.cpp
@@ -35,7 +35,7 @@ public:
         return MemInput_.Read(buf, len);
     }
 
-    inline size_t Skip(size_t len) {
+    inline size_t Skip(size_t len) { 
         size_t totalSkipped = 0;
         while (len) {
             const size_t skipped = DoSkip(len);
@@ -45,11 +45,11 @@ public:
 
             totalSkipped += skipped;
             len -= skipped;
-        }
+        } 
 
         return totalSkipped;
-    }
-
+    } 
+ 
     inline size_t DoSkip(size_t len) {
         if (MemInput_.Exhausted()) {
             if (len > BufLen() / 2) {
@@ -131,10 +131,10 @@ size_t TBufferedInput::DoRead(void* buf, size_t len) {
     return Impl_->Read(buf, len);
 }
 
-size_t TBufferedInput::DoSkip(size_t len) {
-    return Impl_->Skip(len);
-}
-
+size_t TBufferedInput::DoSkip(size_t len) { 
+    return Impl_->Skip(len); 
+} 
+ 
 size_t TBufferedInput::DoNext(const void** ptr, size_t len) {
     return Impl_->Next(ptr, len);
 }
diff --git a/util/stream/buffered_ut.cpp b/util/stream/buffered_ut.cpp
index 41d2fc3030..62a32776de 100644
--- a/util/stream/buffered_ut.cpp
+++ b/util/stream/buffered_ut.cpp
@@ -59,7 +59,7 @@ Y_UNIT_TEST_SUITE(TestBufferedIO) {
 
         UNIT_ASSERT_VALUES_EQUAL(s, "112");
     }
-
+ 
     Y_UNIT_TEST(Test4) {
         TString s;
 
@@ -109,24 +109,24 @@ Y_UNIT_TEST_SUITE(TestBufferedIO) {
 
     Y_UNIT_TEST(TestInput) {
         TString s("0123456789abcdefghijklmn");
-        TBuffered<TStringInput> in(5, s);
-        char c;
+        TBuffered<TStringInput> in(5, s); 
+        char c; 
         UNIT_ASSERT_VALUES_EQUAL(in.Read(&c, 1), 1); //1
-        UNIT_ASSERT_VALUES_EQUAL(c, '0');
+        UNIT_ASSERT_VALUES_EQUAL(c, '0'); 
         UNIT_ASSERT_VALUES_EQUAL(in.Skip(4), 4);     //5 end of buffer
         UNIT_ASSERT_VALUES_EQUAL(in.Read(&c, 1), 1); //6
-        UNIT_ASSERT_VALUES_EQUAL(c, '5');
+        UNIT_ASSERT_VALUES_EQUAL(c, '5'); 
         UNIT_ASSERT_VALUES_EQUAL(in.Skip(3), 3);     //9
         UNIT_ASSERT_VALUES_EQUAL(in.Read(&c, 1), 1); //10 end of buffer
-        UNIT_ASSERT_VALUES_EQUAL(c, '9');
+        UNIT_ASSERT_VALUES_EQUAL(c, '9'); 
         UNIT_ASSERT_VALUES_EQUAL(in.Skip(3), 3);     //13
         UNIT_ASSERT_VALUES_EQUAL(in.Read(&c, 1), 1); //14 start new buffer
-        UNIT_ASSERT_VALUES_EQUAL(c, 'd');
+        UNIT_ASSERT_VALUES_EQUAL(c, 'd'); 
         UNIT_ASSERT_VALUES_EQUAL(in.Skip(6), 6);     //20
         UNIT_ASSERT_VALUES_EQUAL(in.Read(&c, 1), 1); //21 start new buffer
-        UNIT_ASSERT_VALUES_EQUAL(c, 'k');
+        UNIT_ASSERT_VALUES_EQUAL(c, 'k'); 
         UNIT_ASSERT_VALUES_EQUAL(in.Skip(6), 3); //24 eof
-    }
+    } 
 
     Y_UNIT_TEST(TestReadTo) {
         TString s("0123456789abc");
diff --git a/util/stream/direct_io.cpp b/util/stream/direct_io.cpp
index 649033af34..5aab0830e1 100644
--- a/util/stream/direct_io.cpp
+++ b/util/stream/direct_io.cpp
@@ -1,47 +1,47 @@
-#include "direct_io.h"
-
+#include "direct_io.h" 
+ 
 #include <util/generic/utility.h>
 
-size_t TRandomAccessFileInput::DoRead(void* buf, size_t len) {
-    const size_t result = File.Pread(buf, len, Position);
-    Position += result;
-    return result;
-}
-
-TRandomAccessFileInput::TRandomAccessFileInput(TDirectIOBufferedFile& file, ui64 position)
-    : File(file)
-    , Position(position)
-{
-}
-
-size_t TRandomAccessFileInput::DoSkip(size_t len) {
+size_t TRandomAccessFileInput::DoRead(void* buf, size_t len) { 
+    const size_t result = File.Pread(buf, len, Position); 
+    Position += result; 
+    return result; 
+} 
+ 
+TRandomAccessFileInput::TRandomAccessFileInput(TDirectIOBufferedFile& file, ui64 position) 
+    : File(file) 
+    , Position(position) 
+{ 
+} 
+ 
+size_t TRandomAccessFileInput::DoSkip(size_t len) { 
     size_t skiped = Min(len, (size_t)Min((ui64)Max<size_t>(), File.GetLength() - Position));
-    Position += skiped;
-    return skiped;
-}
-
-TRandomAccessFileOutput::TRandomAccessFileOutput(TDirectIOBufferedFile& file)
+    Position += skiped; 
+    return skiped; 
+} 
+ 
+TRandomAccessFileOutput::TRandomAccessFileOutput(TDirectIOBufferedFile& file) 
     : File(&file)
-{
-}
-
-void TRandomAccessFileOutput::DoWrite(const void* buf, size_t len) {
+{ 
+} 
+ 
+void TRandomAccessFileOutput::DoWrite(const void* buf, size_t len) { 
     File->Write(buf, len);
-}
-
-void TRandomAccessFileOutput::DoFlush() {
+} 
+ 
+void TRandomAccessFileOutput::DoFlush() { 
     File->FlushData();
-}
-
+} 
+ 
 TBufferedFileOutputEx::TBufferedFileOutputEx(const TString& path, EOpenMode oMode, size_t buflen)
-    : TRandomAccessFileOutput(*(new TDirectIOBufferedFile(path, oMode, buflen)))
+    : TRandomAccessFileOutput(*(new TDirectIOBufferedFile(path, oMode, buflen))) 
     , FileHolder(File)
-{
-}
-
-void TBufferedFileOutputEx::DoFinish() {
-    FileHolder->Finish();
-}
-
-void TBufferedFileOutputEx::DoFlush() {
-}
+{ 
+} 
+ 
+void TBufferedFileOutputEx::DoFinish() { 
+    FileHolder->Finish(); 
+} 
+ 
+void TBufferedFileOutputEx::DoFlush() { 
+} 
diff --git a/util/stream/direct_io.h b/util/stream/direct_io.h
index 2e1f2e07dd..0c55f15a95 100644
--- a/util/stream/direct_io.h
+++ b/util/stream/direct_io.h
@@ -1,43 +1,43 @@
-#pragma once
-
-#include "input.h"
-#include "output.h"
-#include <util/system/direct_io.h>
-
+#pragma once 
+ 
+#include "input.h" 
+#include "output.h" 
+#include <util/system/direct_io.h> 
+ 
 class TRandomAccessFileInput: public IInputStream {
-public:
-    TRandomAccessFileInput(TDirectIOBufferedFile& file, ui64 position);
-
-protected:
+public: 
+    TRandomAccessFileInput(TDirectIOBufferedFile& file, ui64 position); 
+ 
+protected: 
     size_t DoRead(void* buf, size_t len) override;
     size_t DoSkip(size_t len) override;
-
-private:
-    TDirectIOBufferedFile& File;
-    ui64 Position;
-};
-
+ 
+private: 
+    TDirectIOBufferedFile& File; 
+    ui64 Position; 
+}; 
+ 
 class TRandomAccessFileOutput: public IOutputStream {
-public:
-    TRandomAccessFileOutput(TDirectIOBufferedFile& file);
-
+public: 
+    TRandomAccessFileOutput(TDirectIOBufferedFile& file); 
+ 
     TRandomAccessFileOutput(TRandomAccessFileOutput&&) noexcept = default;
     TRandomAccessFileOutput& operator=(TRandomAccessFileOutput&&) noexcept = default;
 
-protected:
+protected: 
     TDirectIOBufferedFile* File;
-
-private:
+ 
+private: 
     void DoWrite(const void* buf, size_t len) override;
     void DoFlush() override;
-};
-
-class TBufferedFileOutputEx: public TRandomAccessFileOutput {
-public:
+}; 
+ 
+class TBufferedFileOutputEx: public TRandomAccessFileOutput { 
+public: 
     TBufferedFileOutputEx(const TString& path, EOpenMode oMode, size_t buflen = 1 << 17);
-
-private:
+ 
+private: 
     void DoFlush() override;
     void DoFinish() override;
-    THolder<TDirectIOBufferedFile> FileHolder;
-};
+    THolder<TDirectIOBufferedFile> FileHolder; 
+}; 
diff --git a/util/stream/direct_io_ut.cpp b/util/stream/direct_io_ut.cpp
index 01d09db232..0dbc2454f2 100644
--- a/util/stream/direct_io_ut.cpp
+++ b/util/stream/direct_io_ut.cpp
@@ -1,12 +1,12 @@
 #include <library/cpp/testing/unittest/registar.h>
-
+ 
 #include <util/generic/string.h>
 #include <util/generic/array_size.h>
 #include <util/system/env.h>
-
+ 
 #include "buffered.h"
 #include "direct_io.h"
-
+ 
 Y_UNIT_TEST_SUITE(TDirectIOTests) {
     // Decrease numBufToWrite further if tests continue to time out
     static void Y_NO_INLINE Test(EOpenMode mode, size_t numBufToWrite) {
@@ -55,8 +55,8 @@ Y_UNIT_TEST_SUITE(TDirectIOTests) {
         }
 
         UNIT_ASSERT_VALUES_EQUAL(bytesRead, numBufToWrite * BUFFER_SIZE);
-    }
-
+    } 
+ 
     Y_UNIT_TEST(ReadWriteTest) {
         Test(0, 100 * 32);
     }
@@ -67,5 +67,5 @@ Y_UNIT_TEST_SUITE(TDirectIOTests) {
 
     Y_UNIT_TEST(ReadWriteDirectSeqTest) {
         Test(Direct | Seq, 100 * 4);
-    }
-}
+    } 
+} 
diff --git a/util/stream/ios_ut.cpp b/util/stream/ios_ut.cpp
index 139f4296e5..2094295103 100644
--- a/util/stream/ios_ut.cpp
+++ b/util/stream/ios_ut.cpp
@@ -2,7 +2,7 @@
 #include "tokenizer.h"
 #include "buffer.h"
 #include "buffered.h"
-#include "walk.h"
+#include "walk.h" 
 
 #include <library/cpp/testing/unittest/registar.h>
 
@@ -23,8 +23,8 @@ class TStreamsTest: public TTestBase {
     UNIT_TEST(TestBufferStream);
     UNIT_TEST(TestStringStream);
     UNIT_TEST(TestWtrokaInput);
-    UNIT_TEST(TestStrokaInput);
-    UNIT_TEST(TestReadTo);
+    UNIT_TEST(TestStrokaInput); 
+    UNIT_TEST(TestReadTo); 
     UNIT_TEST(TestWtrokaOutput);
     UNIT_TEST(TestIStreamOperators);
     UNIT_TEST(TestWchar16Output);
@@ -41,10 +41,10 @@ public:
     void TestBufferStream();
     void TestStringStream();
     void TestWtrokaInput();
-    void TestStrokaInput();
+    void TestStrokaInput(); 
     void TestWtrokaOutput();
     void TestIStreamOperators();
-    void TestReadTo();
+    void TestReadTo(); 
     void TestWchar16Output();
     void TestWchar32Output();
     void TestUtf16StingOutputByChars();
@@ -280,30 +280,30 @@ void TStreamsTest::TestBufferStream() {
 
 namespace {
     class TStringListInput: public IWalkInput {
-    public:
+    public: 
         TStringListInput(const TVector<TString>& data)
-            : Data_(data)
-            , Index_(0)
-        {
-        }
-
-    protected:
-        size_t DoUnboundedNext(const void** ptr) override {
-            if (Index_ >= Data_.size()) {
-                return 0;
-            }
-
+            : Data_(data) 
+            , Index_(0) 
+        { 
+        } 
+ 
+    protected: 
+        size_t DoUnboundedNext(const void** ptr) override { 
+            if (Index_ >= Data_.size()) { 
+                return 0; 
+            } 
+ 
             const TString& string = Data_[Index_++];
-
-            *ptr = string.data();
-            return string.size();
-        }
-
-    private:
+ 
+            *ptr = string.data(); 
+            return string.size(); 
+        } 
+ 
+    private: 
         const TVector<TString>& Data_;
-        size_t Index_;
-    };
-
+        size_t Index_; 
+    }; 
+ 
     const char Text[] =
         // UTF8 encoded "one \ntwo\r\nthree\n\tfour\nfive\n" in russian and ...
         "один \n"
@@ -335,18 +335,18 @@ namespace {
         TString tmp;
         input.ReadTo(tmp, 'c');
         UNIT_ASSERT_VALUES_EQUAL_C(tmp, "111a222b333", comment);
-
+ 
         char tmp2;
         input.Read(&tmp2, 1);
         UNIT_ASSERT_VALUES_EQUAL_C(tmp2, '4', comment);
-
+ 
         input.ReadTo(tmp, '6');
         UNIT_ASSERT_VALUES_EQUAL_C(tmp, "44d555e", comment);
-
+ 
         tmp = input.ReadAll();
         UNIT_ASSERT_VALUES_EQUAL_C(tmp, "66f", comment);
     }
-
+ 
     void TestStreamReadTo2(IInputStream& input, const char* comment) {
         TString s;
         size_t i = 0;
@@ -354,30 +354,30 @@ namespace {
             UNIT_ASSERT_C(i < Y_ARRAY_SIZE(Expected), comment);
             UNIT_ASSERT_VALUES_EQUAL_C(s, Expected[i], comment);
             ++i;
-        }
+        } 
     }
-
+ 
     void TestStreamReadTo3(IInputStream& input, const char* comment) {
         UNIT_ASSERT_VALUES_EQUAL_C(input.ReadLine(), "111a222b333c444d555e666f", comment);
     }
-
+ 
     void TestStreamReadTo4(IInputStream& input, const char* comment) {
         UNIT_ASSERT_VALUES_EQUAL_C(input.ReadTo('\0'), "one", comment);
         UNIT_ASSERT_VALUES_EQUAL_C(input.ReadTo('\0'), "two", comment);
         UNIT_ASSERT_VALUES_EQUAL_C(input.ReadTo('\0'), "three", comment);
     }
-
+ 
     void TestStrokaInput(IInputStream& input, const char* comment) {
         TString line;
         ui32 i = 0;
         TInstant start = Now();
         while (input.ReadLine(line)) {
             ++i;
-        }
+        } 
         Cout << comment << ":" << (Now() - start).SecondsFloat() << Endl;
         UNIT_ASSERT_VALUES_EQUAL(i, 100000);
     }
-
+ 
     template <class T>
     void TestStreamReadTo(const TString& text, T test) {
         TStringInput is(text);
@@ -396,25 +396,25 @@ namespace {
     }
 }
 
-void TStreamsTest::TestReadTo() {
-    TestStreamReadTo("111a222b333c444d555e666f", TestStreamReadTo1);
-    TestStreamReadTo(Text, TestStreamReadTo2);
-    TestStreamReadTo("111a222b333c444d555e666f", TestStreamReadTo3);
+void TStreamsTest::TestReadTo() { 
+    TestStreamReadTo("111a222b333c444d555e666f", TestStreamReadTo1); 
+    TestStreamReadTo(Text, TestStreamReadTo2); 
+    TestStreamReadTo("111a222b333c444d555e666f", TestStreamReadTo3); 
     TString withZero = "one";
-    withZero.append('\0').append("two").append('\0').append("three");
-    TestStreamReadTo(withZero, TestStreamReadTo4);
-}
-
-void TStreamsTest::TestStrokaInput() {
+    withZero.append('\0').append("two").append('\0').append("three"); 
+    TestStreamReadTo(withZero, TestStreamReadTo4); 
+} 
+ 
+void TStreamsTest::TestStrokaInput() { 
     TString s;
-    for (ui32 i = 0; i < 100000; ++i) {
+    for (ui32 i = 0; i < 100000; ++i) { 
         TVector<char> d(i % 1000, 'a');
         s.append(d.data(), d.size());
-        s.append('\n');
-    }
+        s.append('\n'); 
+    } 
     TestStreamReadTo(s, ::TestStrokaInput);
-}
-
+} 
+ 
 void TStreamsTest::TestWtrokaInput() {
     const TString s(Text);
     TStringInput is(s);
diff --git a/util/stream/mem.cpp b/util/stream/mem.cpp
index 22a3339e27..68778a86f2 100644
--- a/util/stream/mem.cpp
+++ b/util/stream/mem.cpp
@@ -31,7 +31,7 @@ size_t TMemoryInput::DoNext(const void** ptr, size_t len) {
     return len;
 }
 
-void TMemoryInput::DoUndo(size_t len) {
+void TMemoryInput::DoUndo(size_t len) { 
     Len_ += len;
     Buf_ -= len;
 }
diff --git a/util/stream/mem.h b/util/stream/mem.h
index 18a5d46772..383e49dfd5 100644
--- a/util/stream/mem.h
+++ b/util/stream/mem.h
@@ -98,7 +98,7 @@ public:
 
 private:
     size_t DoNext(const void** ptr, size_t len) override;
-    void DoUndo(size_t len) override;
+    void DoUndo(size_t len) override; 
 
 private:
     const char* Buf_;
diff --git a/util/stream/str.cpp b/util/stream/str.cpp
index 13f0e8ef28..e1b6e72d67 100644
--- a/util/stream/str.cpp
+++ b/util/stream/str.cpp
@@ -11,11 +11,11 @@ size_t TStringInput::DoNext(const void** ptr, size_t len) {
     return len;
 }
 
-void TStringInput::DoUndo(size_t len) {
-    Y_VERIFY(len <= Pos_);
-    Pos_ -= len;
-}
-
+void TStringInput::DoUndo(size_t len) { 
+    Y_VERIFY(len <= Pos_); 
+    Pos_ -= len; 
+} 
+ 
 TStringOutput::~TStringOutput() = default;
 
 size_t TStringOutput::DoNext(void** ptr) {
diff --git a/util/stream/str.h b/util/stream/str.h
index 028bd572c0..89f42c1fd7 100644
--- a/util/stream/str.h
+++ b/util/stream/str.h
@@ -49,7 +49,7 @@ public:
 
 protected:
     size_t DoNext(const void** ptr, size_t len) override;
-    void DoUndo(size_t len) override;
+    void DoUndo(size_t len) override; 
 
 private:
     const TString* S_;
diff --git a/util/stream/walk.cpp b/util/stream/walk.cpp
index 57dc9ab036..47a6cae5f8 100644
--- a/util/stream/walk.cpp
+++ b/util/stream/walk.cpp
@@ -3,8 +3,8 @@
 #include <util/generic/string.h>
 
 void IWalkInput::DoUndo(size_t len) {
-    Len_ += len;
-    Buf_ = static_cast<const char*>(Buf_) - len;
+    Len_ += len; 
+    Buf_ = static_cast<const char*>(Buf_) - len; 
 }
 
 size_t IWalkInput::DoNext(const void** ptr, size_t len) {
diff --git a/util/stream/walk.h b/util/stream/walk.h
index 7e62cb44dc..9683943331 100644
--- a/util/stream/walk.h
+++ b/util/stream/walk.h
@@ -16,7 +16,7 @@ public:
     }
 
 protected:
-    void DoUndo(size_t len) override;
+    void DoUndo(size_t len) override; 
     size_t DoNext(const void** ptr, size_t len) override;
 
     /**
diff --git a/util/stream/zerocopy.cpp b/util/stream/zerocopy.cpp
index dc2982ad55..b5f8e58b70 100644
--- a/util/stream/zerocopy.cpp
+++ b/util/stream/zerocopy.cpp
@@ -31,30 +31,30 @@ size_t IZeroCopyInput::DoSkip(size_t len) {
 
     return DoNext(&ptr, len);
 }
-
+ 
 IZeroCopyInputFastReadTo::~IZeroCopyInputFastReadTo() = default;
-
+ 
 size_t IZeroCopyInputFastReadTo::DoReadTo(TString& st, char ch) {
-    const char* ptr;
-    size_t len = Next(&ptr);
-    if (!len) {
-        return 0;
-    }
-    size_t result = 0;
-    st.clear();
-    do {
-        if (const char* pos = (const char*)memchr(ptr, ch, len)) {
+    const char* ptr; 
+    size_t len = Next(&ptr); 
+    if (!len) { 
+        return 0; 
+    } 
+    size_t result = 0; 
+    st.clear(); 
+    do { 
+        if (const char* pos = (const char*)memchr(ptr, ch, len)) { 
             size_t bytesRead = (pos - ptr) + 1;
             if (bytesRead > 1) {
-                st.append(ptr, pos);
-            }
+                st.append(ptr, pos); 
+            } 
             Undo(len - bytesRead);
             result += bytesRead;
-            return result;
-        } else {
-            result += len;
-            st.append(ptr, len);
-        }
-    } while (len = Next(&ptr));
-    return result;
-}
+            return result; 
+        } else { 
+            result += len; 
+            st.append(ptr, len); 
+        } 
+    } while (len = Next(&ptr)); 
+    return result; 
+} 
diff --git a/util/stream/zerocopy.h b/util/stream/zerocopy.h
index 3315aa3a51..d44d5e0d77 100644
--- a/util/stream/zerocopy.h
+++ b/util/stream/zerocopy.h
@@ -56,36 +56,36 @@ protected:
     virtual size_t DoNext(const void** ptr, size_t len) = 0;
 };
 
-/**
-* Input stream with direct access to the input buffer and ability to undo read
-*
-* Derived classes must implement `DoUndo` method.
-*/
+/** 
+* Input stream with direct access to the input buffer and ability to undo read 
+* 
+* Derived classes must implement `DoUndo` method. 
+*/ 
 class IZeroCopyInputFastReadTo: public IZeroCopyInput {
-public:
+public: 
     IZeroCopyInputFastReadTo() noexcept = default;
     ~IZeroCopyInputFastReadTo() override;
-
+ 
     IZeroCopyInputFastReadTo(IZeroCopyInputFastReadTo&&) noexcept = default;
     IZeroCopyInputFastReadTo& operator=(IZeroCopyInputFastReadTo&&) noexcept = default;
 
-protected:
+protected: 
     size_t DoReadTo(TString& st, char ch) override;
-
-private:
-    /**
-    * Undo read.
-    *
-    * Note that this function not check if you try undo more that read. In fact Undo used for undo read in last chunk.
-    *
-    * @param len[in]                   Bytes to undo.
-    */
-    inline void Undo(size_t len) {
-        if (len) {
-            DoUndo(len);
-        }
-    }
-    virtual void DoUndo(size_t len) = 0;
-};
-
+ 
+private: 
+    /** 
+    * Undo read. 
+    * 
+    * Note that this function not check if you try undo more that read. In fact Undo used for undo read in last chunk. 
+    * 
+    * @param len[in]                   Bytes to undo. 
+    */ 
+    inline void Undo(size_t len) { 
+        if (len) { 
+            DoUndo(len); 
+        } 
+    } 
+    virtual void DoUndo(size_t len) = 0; 
+}; 
+ 
 /** @} */