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Diffstat (limited to 'src/md/databuffer.h')
| -rw-r--r-- | src/md/databuffer.h | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/src/md/databuffer.h b/src/md/databuffer.h new file mode 100644 index 0000000000..c1e9410738 --- /dev/null +++ b/src/md/databuffer.h @@ -0,0 +1,156 @@ +// Licensed to the .NET Foundation under one or more agreements. +// The .NET Foundation licenses this file to you under the MIT license. +// See the LICENSE file in the project root for more information. +// +// File: DataBuffer.h +// + +// +// Class code:DataBuffer provides secure access to a block of memory. +// +// ====================================================================================== + +#pragma once + +#include "external.h" + +// -------------------------------------------------------------------------------------- +// +// This class provides secure access to a block of memory. +// +class DataBuffer +{ +private: + // + // Private data + // + + // The memory block of size code:m_cbSize. Can be non-NULL even if code:m_cbSize is 0. + __field_bcount(m_cbSize) + BYTE *m_pbData; + // Size of the memory block starting at code:m_pbData. If it is 0, then value of code:m_pbData can be + // anything (incl. NULL). + UINT32 m_cbSize; + +public: + // + // Initialization + // + + // Creates empty memory block. + inline DataBuffer(); + // Creates memory block (pbData, of size cbSize). + inline DataBuffer( + __in_bcount(cbSize) BYTE *pbData, + UINT32 cbSize); + // Creates memory block copy. + inline DataBuffer( + const DataBuffer &source); + // Initializes memory block to empty data. The object could be already initialzied. + inline void Clear(); + // Initializes memory block to data (pbData, of size cbSize). The object should be empty before. + inline void Init( + __in_bcount(cbSize) BYTE *pbData, + UINT32 cbSize); + + // + // Getters + // + + // Reads data of type T without skipping the read data (returns pointer to the type in *ppTypeData). + // Returns FALSE if there's not enough data (of size T) in the blob, doesn't initialize the pointer + // *ppTypeData then. + // Returns TRUE otherwise, fills *ppTypeData with the "read" type start, but doesn't move the memory + // block (doesn't skip the "read" data). + template<class T> + __checkReturn + inline BOOL PeekData( + __deref_out T **ppTypeData); + // Reads data of type T at offset nOffset without skipping the read data (returns pointer to the type in + // *ppTypeData). + // Returns FALSE if there's not enough data (of size T) at offset nOffset in the buffer, doesn't + // initialize the pointer *ppTypeData then. + // Returns TRUE otherwise, fills *ppTypeData with the type start, but doesn't move the memory block + // (doesn't skip any "read" data). + template<class T> + __checkReturn + inline BOOL PeekDataAt( + UINT32 nOffset, + __deref_out T **ppTypeData); + // Reads data of type T and skips the data (instead of reading the bytes, returns pointer to the type in + // *ppTypeData). + // Returns FALSE if there's not enough data (of size T) in the blob, doesn't initialize the pointer + // *ppTypeData then. + // Returns TRUE otherwise, fills *ppTypeData with the "read" type start and moves the memory block + // behind the "read" type. + template<class T> + __checkReturn + inline BOOL GetData( + __deref_out T **ppTypeData); + // Reads data of size cbDataSize and skips the data (instead of reading the bytes, returns pointer to + // the bytes in *ppbDataPointer). + // Returns FALSE if there's not enough data in the blob, doesn't initialize the pointer *ppbDataPointer + // then. + // Returns TRUE otherwise, fills *ppbDataPointer with the "read" data start and moves the memory block + // behind the "read" data. + __checkReturn + inline BOOL GetDataOfSize( + UINT32 cbDataSize, + __out_bcount(cbDataSize) BYTE **ppbDataPointer); + + // Returns TRUE if the represented memory is empty. + inline BOOL IsEmpty() const + { return (m_cbSize == 0); } + // Gets pointer to the represented data buffer (can be random pointer if size of the data is 0). + // Note: Should be used exceptionally. Try to use other operations instead. + inline BYTE *GetDataPointer() + { return m_pbData; } + // Gets pointer to the represented data buffer (can be random pointer if size of the data is 0). + // Note: Should be used exceptionally. Try to use other operations instead. + inline const BYTE *GetDataPointer() const + { return m_pbData; } + // Gets pointer right behind the represented data buffer (can be random pointer if size of the data is + // 0). + inline const BYTE *GetDataPointerBehind() const + { return m_pbData + m_cbSize; } + // Gets the size of represented memory. + inline UINT32 GetSize() const + { return m_cbSize; } + //BOOL SkipBytes(UINT32 cbSize); + +public: + // + // Operations + // + + // Truncates the buffer to exact size (cbSize). + // Returns FALSE if there's less than cbSize data represented. + // Returns TRUE otherwise and truncates the represented data size to cbSize. + __checkReturn + inline BOOL TruncateToExactSize(UINT32 cbSize); + // Truncates the buffer by size (cbSize). + // Returns FALSE if there's less than cbSize data represented. + // Returns TRUE otherwise and truncates the represented data size by cbSize. + __checkReturn + inline BOOL TruncateBySize(UINT32 cbSize); + + // Skips the buffer to exact size (cbSize). + // Returns FALSE if there's less than cbSize data represented. + // Returns TRUE otherwise and skips data at the beggining, so that the result has size cbSize. + __checkReturn + inline BOOL SkipToExactSize(UINT32 cbSize); + +private: + // + // Helpers + // + + // Skips 'cbSize' bytes in the represented memory block. The caller is responsible for making sure that + // the represented memory block contains at least 'cbSize' bytes, otherwise there will be a security + // issue. + // Should be used only internally, never call it from outside of this class. + inline void SkipBytes_InternalInsecure(UINT32 cbSize); + +}; // class DataBuffer + +#include "databuffer.inl" |