libcamera  v0.3.1+12-19bbca3c
Supporting cameras in Linux since 2019
byte_stream_buffer.h
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1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
2 /*
3  * Copyright (C) 2019, Google Inc.
4  *
5  * Byte stream buffer
6  */
7 
8 #pragma once
9 
10 #include <stddef.h>
11 #include <stdint.h>
12 #include <type_traits>
13 
14 #include <libcamera/base/class.h>
15 #include <libcamera/base/span.h>
16 
17 namespace libcamera {
18 
20 {
21 public:
22  ByteStreamBuffer(const uint8_t *base, size_t size);
23  ByteStreamBuffer(uint8_t *base, size_t size);
26 
27  const uint8_t *base() const { return base_; }
28  uint32_t offset() const { return (write_ ? write_ : read_) - base_; }
29  size_t size() const { return size_; }
30  bool overflow() const { return overflow_; }
31 
32  ByteStreamBuffer carveOut(size_t size);
33  int skip(size_t size);
34 
35  template<typename T>
36  int read(T *t)
37  {
38  return read(reinterpret_cast<uint8_t *>(t), sizeof(*t));
39  }
40 
41  template<typename T>
42  int read(const Span<T> &data)
43  {
44  return read(reinterpret_cast<uint8_t *>(data.data()),
45  data.size_bytes());
46  }
47 
48  template<typename T>
49  const std::remove_reference_t<T> *read(size_t count = 1)
50  {
51  using return_type = const std::remove_reference_t<T> *;
52  return reinterpret_cast<return_type>(read(sizeof(T), count));
53  }
54 
55  template<typename T>
56  int write(const T *t)
57  {
58  return write(reinterpret_cast<const uint8_t *>(t), sizeof(*t));
59  }
60 
61  template<typename T>
62  int write(const Span<T> &data)
63  {
64  return write(reinterpret_cast<const uint8_t *>(data.data()),
65  data.size_bytes());
66  }
67 
68 private:
70 
71  void setOverflow();
72 
73  int read(uint8_t *data, size_t size);
74  const uint8_t *read(size_t size, size_t count);
75  int write(const uint8_t *data, size_t size);
76 
77  ByteStreamBuffer *parent_;
78 
79  const uint8_t *base_;
80  size_t size_;
81  bool overflow_;
82 
83  const uint8_t *read_;
84  uint8_t *write_;
85 };
86 
87 } /* namespace libcamera */
bool overflow() const
Check if the buffer has overflown.
Definition: byte_stream_buffer.h:30
Utilities to help constructing class interfaces.
int write(const Span< T > &data)
Write data to the managed memory buffer.
Definition: byte_stream_buffer.h:62
const uint8_t * base() const
Retrieve a pointer to the start location of the managed memory buffer.
Definition: byte_stream_buffer.h:27
Top-level libcamera namespace.
Definition: backtrace.h:17
ByteStreamBuffer(const uint8_t *base, size_t size)
Construct a read ByteStreamBuffer from the memory area base of size.
Definition: byte_stream_buffer.cpp:65
size_t size() const
Retrieve the size of the managed memory buffer.
Definition: byte_stream_buffer.h:29
uint32_t offset() const
Retrieve the offset of the current access location from the base.
Definition: byte_stream_buffer.h:28
int skip(size_t size)
Skip size bytes from the buffer.
Definition: byte_stream_buffer.cpp:203
#define LIBCAMERA_DISABLE_COPY(klass)
Disable copy construction and assignment of the klass.
ByteStreamBuffer & operator=(ByteStreamBuffer &&other)
Replace the contents of the buffer with those of other using move semantics.
Definition: byte_stream_buffer.cpp:104
ByteStreamBuffer carveOut(size_t size)
Carve out an area of size bytes into a new ByteStreamBuffer.
Definition: byte_stream_buffer.cpp:167
Wrap a memory buffer and provide sequential data read and write.
Definition: byte_stream_buffer.h:19
const std::remove_reference_t< T > * read(size_t count=1)
Read data from the managed memory buffer without performing a copy.
Definition: byte_stream_buffer.h:49
int write(const T *t)
Write t to the managed memory buffer.
Definition: byte_stream_buffer.h:56
int read(T *t)
Read data from the managed memory buffer into t.
Definition: byte_stream_buffer.h:36
int read(const Span< T > &data)
Read data from the managed memory buffer into Span data.
Definition: byte_stream_buffer.h:42