1//===-- DataBufferHeap.h ----------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef LLDB_UTILITY_DATABUFFERHEAP_H
10#define LLDB_UTILITY_DATABUFFERHEAP_H
11
12#include "lldb/Utility/DataBuffer.h"
13#include "lldb/lldb-types.h"
14#include "llvm/ADT/StringRef.h"
15
16#include <cstdint>
17#include <vector>
18
19namespace lldb_private {
20
21/// \class DataBufferHeap DataBufferHeap.h "lldb/Core/DataBufferHeap.h"
22/// A subclass of DataBuffer that stores a data buffer on the heap.
23///
24/// This class keeps its data in a heap based buffer that is owned by the
25/// object. This class is best used to store chunks of data that are created
26/// or read from sources that can't intelligently and lazily fault new data
27/// pages in. Large amounts of data that comes from files should probably use
28/// DataBufferLLVM, which can intelligently determine when memory mapping is
29/// optimal.
30class DataBufferHeap : public WritableDataBuffer {
31public:
32  /// Default constructor
33  ///
34  /// Initializes the heap based buffer with no bytes.
35  DataBufferHeap();
36
37  /// Construct with size \a n and fill with \a ch.
38  ///
39  /// Initialize this class with \a n bytes and fills the buffer with \a ch.
40  ///
41  /// \param[in] n
42  ///     The number of bytes that heap based buffer should contain.
43  ///
44  /// \param[in] ch
45  ///     The character to use when filling the buffer initially.
46  DataBufferHeap(lldb::offset_t n, uint8_t ch);
47
48  /// Construct by making a copy of \a src_len bytes from \a src.
49  ///
50  /// \param[in] src
51  ///     A pointer to the data to copy.
52  ///
53  /// \param[in] src_len
54  ///     The number of bytes in \a src to copy.
55  DataBufferHeap(const void *src, lldb::offset_t src_len);
56
57  /// Construct by making a copy of a DataBuffer.
58  ///
59  /// \param[in] data_buffer
60  ///     A read only data buffer to copy.
61  DataBufferHeap(const DataBuffer &data_buffer);
62
63  /// Destructor.
64  ///
65  /// Virtual destructor since this class inherits from a pure virtual base
66  /// class #DataBuffer.
67  ~DataBufferHeap() override;
68
69  /// \copydoc DataBuffer::GetBytes() const
70  const uint8_t *GetBytesImpl() const override;
71
72  /// \copydoc DataBuffer::GetByteSize() const
73  lldb::offset_t GetByteSize() const override;
74
75  /// Set the number of bytes in the data buffer.
76  ///
77  /// Sets the number of bytes that this object should be able to contain.
78  /// This can be used prior to copying data into the buffer. Note that this
79  /// zero-initializes up to \p byte_size bytes.
80  ///
81  /// \param[in] byte_size
82  ///     The new size in bytes that this data buffer should attempt
83  ///     to resize itself to.
84  ///
85  /// \return
86  ///     The size in bytes after this heap buffer was resized. If
87  ///     the resize failed the size will remain unchanged.
88  lldb::offset_t SetByteSize(lldb::offset_t byte_size);
89
90  /// Makes a copy of the \a src_len bytes in \a src.
91  ///
92  /// Copies the data in \a src into an internal buffer.
93  ///
94  /// \param[in] src
95  ///     A pointer to the data to copy.
96  ///
97  /// \param[in] src_len
98  ///     The number of bytes in \a src to copy.
99  void CopyData(const void *src, lldb::offset_t src_len);
100  void CopyData(llvm::StringRef src) { CopyData(src.data(), src.size()); }
101
102  void AppendData(const void *src, uint64_t src_len);
103
104  void Clear();
105
106  /// LLVM RTTI support.
107  /// {
108  static char ID;
109  bool isA(const void *ClassID) const override {
110    return ClassID == &ID || WritableDataBuffer::isA(ClassID);
111  }
112  static bool classof(const DataBuffer *data_buffer) {
113    return data_buffer->isA(&ID);
114  }
115  /// }
116
117private:
118  // This object uses a std::vector<uint8_t> to store its data. This takes care
119  // of free the data when the object is deleted.
120  typedef std::vector<uint8_t> buffer_t; ///< Buffer type
121  buffer_t m_data; ///< The heap based buffer where data is stored
122};
123
124} // namespace lldb_private
125
126#endif // LLDB_UTILITY_DATABUFFERHEAP_H
127