lldb/Utility/DataBufferHeap.h

0001 //===-- DataBufferHeap.h ----------------------------------------*- C++ -*-===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef LLDB_UTILITY_DATABUFFERHEAP_H
0010 #define LLDB_UTILITY_DATABUFFERHEAP_H
0011
0012 #include "lldb/Utility/DataBuffer.h"
0013 #include "lldb/lldb-types.h"
0014 #include "llvm/ADT/StringRef.h"
0015
0016 #include <cstdint>
0017 #include <vector>
0018
0019 namespace lldb_private {
0020
0021 /// \class DataBufferHeap DataBufferHeap.h "lldb/Core/DataBufferHeap.h"
0022 /// A subclass of DataBuffer that stores a data buffer on the heap.
0023 ///
0024 /// This class keeps its data in a heap based buffer that is owned by the
0025 /// object. This class is best used to store chunks of data that are created
0026 /// or read from sources that can't intelligently and lazily fault new data
0027 /// pages in. Large amounts of data that comes from files should probably use
0028 /// DataBufferLLVM, which can intelligently determine when memory mapping is
0029 /// optimal.
0030 class DataBufferHeap : public WritableDataBuffer {
0031 public:
0032   /// Default constructor
0033   ///
0034   /// Initializes the heap based buffer with no bytes.
0035   DataBufferHeap();
0036
0037   /// Construct with size \a n and fill with \a ch.
0038   ///
0039   /// Initialize this class with \a n bytes and fills the buffer with \a ch.
0040   ///
0041   /// \param[in] n
0042   ///     The number of bytes that heap based buffer should contain.
0043   ///
0044   /// \param[in] ch
0045   ///     The character to use when filling the buffer initially.
0046   DataBufferHeap(lldb::offset_t n, uint8_t ch);
0047
0048   /// Construct by making a copy of \a src_len bytes from \a src.
0049   ///
0050   /// \param[in] src
0051   ///     A pointer to the data to copy.
0052   ///
0053   /// \param[in] src_len
0054   ///     The number of bytes in \a src to copy.
0055   DataBufferHeap(const void *src, lldb::offset_t src_len);
0056
0057   /// Construct by making a copy of a DataBuffer.
0058   ///
0059   /// \param[in] data_buffer
0060   ///     A read only data buffer to copy.
0061   DataBufferHeap(const DataBuffer &data_buffer);
0062
0063   /// Destructor.
0064   ///
0065   /// Virtual destructor since this class inherits from a pure virtual base
0066   /// class #DataBuffer.
0067   ~DataBufferHeap() override;
0068
0069   /// \copydoc DataBuffer::GetBytes() const
0070   const uint8_t *GetBytesImpl() const override;
0071
0072   /// \copydoc DataBuffer::GetByteSize() const
0073   lldb::offset_t GetByteSize() const override;
0074
0075   /// Set the number of bytes in the data buffer.
0076   ///
0077   /// Sets the number of bytes that this object should be able to contain.
0078   /// This can be used prior to copying data into the buffer. Note that this
0079   /// zero-initializes up to \p byte_size bytes.
0080   ///
0081   /// \param[in] byte_size
0082   ///     The new size in bytes that this data buffer should attempt
0083   ///     to resize itself to.
0084   ///
0085   /// \return
0086   ///     The size in bytes after this heap buffer was resized. If
0087   ///     the resize failed the size will remain unchanged.
0088   lldb::offset_t SetByteSize(lldb::offset_t byte_size);
0089
0090   /// Makes a copy of the \a src_len bytes in \a src.
0091   ///
0092   /// Copies the data in \a src into an internal buffer.
0093   ///
0094   /// \param[in] src
0095   ///     A pointer to the data to copy.
0096   ///
0097   /// \param[in] src_len
0098   ///     The number of bytes in \a src to copy.
0099   void CopyData(const void *src, lldb::offset_t src_len);
0100   void CopyData(llvm::StringRef src) { CopyData(src.data(), src.size()); }
0101
0102   void AppendData(const void *src, uint64_t src_len);
0103
0104   void Clear();
0105
0106   /// LLVM RTTI support.
0107   /// {
0108   static char ID;
0109   bool isA(const void *ClassID) const override {
0110     return ClassID == &ID || WritableDataBuffer::isA(ClassID);
0111   }
0112   static bool classof(const DataBuffer *data_buffer) {
0113     return data_buffer->isA(&ID);
0114   }
0115   /// }
0116
0117 private:
0118   // This object uses a std::vector<uint8_t> to store its data. This takes care
0119   // of free the data when the object is deleted.
0120   typedef std::vector<uint8_t> buffer_t; ///< Buffer type
0121   buffer_t m_data; ///< The heap based buffer where data is stored
0122 };
0123
0124 } // namespace lldb_private
0125
0126 #endif // LLDB_UTILITY_DATABUFFERHEAP_H