nlib
InputStream.h
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1 
2 /*--------------------------------------------------------------------------------*
3  Project: CrossRoad
4  Copyright (C)Nintendo All rights reserved.
5 
6  These coded instructions, statements, and computer programs contain proprietary
7  information of Nintendo and/or its licensed developers and are protected by
8  national and international copyright laws. They may not be disclosed to third
9  parties or copied or duplicated in any form, in whole or in part, without the
10  prior written consent of Nintendo.
11 
12  The content herein is highly confidential and should be handled accordingly.
13  *--------------------------------------------------------------------------------*/
14 
15 #pragma once
16 #ifndef INCLUDE_NN_NLIB_INPUTSTREAM_H_
17 #define INCLUDE_NN_NLIB_INPUTSTREAM_H_
18 
19 #include "nn/nlib/Config.h"
20 #include "nn/nlib/TypeTraits.h"
21 
22 NLIB_NAMESPACE_BEGIN
23 
24 // code snippets:
25 // InputStream& stream = 'stream that inherits InputStream';
26 // if (!stream.Read(dataptr, nbyte)) { error = stream.GetErrorValue(); ..... }
27 // while ((c = stream.Read()) >= 0) { c is [0x00 - 0xFF] }
28 // if (!stream) { error = stream.GetErrorValue(); ..... }
30  public:
32  is_buf_curidx_(0),
33  is_buf_endidx_(0),
34  is_buf_(NULL),
35  is_bufsize_(0),
36  errno_(0) {}
38  // NOTE:
39  // cannot call Close_() from this destructor.
40  // the destructor of the derived class has to call Close_() if needed.
41  }
42  // returns true if there has been no errors
43  // you can also write the codes such that 'if (!!stream) { ... }'
44  errno_t GetErrorValue() const NLIB_NOEXCEPT { return errno_; }
45  // use Pos64() if you need a 64bit value on 32bit arch
46  size_t Pos() const NLIB_NOEXCEPT { return static_cast<size_t>(Pos64()); }
47  uint64_t Pos64() const NLIB_NOEXCEPT { return pos_ + is_buf_curidx_; }
49  if (*this && is_buf_curidx_ == is_buf_endidx_) {
50  CheckBuffer();
51  return *this && is_buf_curidx_ == is_buf_endidx_;
52  }
53  return false;
54  }
55  // < 0 if EOS or error, otherwise returns a byte and ++pos
57  if (NLIB_UNLIKELY(is_buf_curidx_ == is_buf_endidx_)) {
58  CheckBuffer();
59  if (NLIB_UNLIKELY(is_buf_curidx_ == is_buf_endidx_)) return -1;
60  }
61  return is_buf_[is_buf_curidx_++];
62  }
63  // < 0 if EOS or error, otherwise returns a byte and pos is unchanged
65  if (NLIB_UNLIKELY(is_buf_curidx_ == is_buf_endidx_)) {
66  CheckBuffer();
67  if (NLIB_UNLIKELY(is_buf_curidx_ == is_buf_endidx_)) return -1;
68  }
69  return is_buf_[is_buf_curidx_];
70  }
71  // returns skipped number of bytes
72  size_t Skip(size_t nbytes) NLIB_NOEXCEPT;
73  size_t Read(void* ptr, size_t nbytes) NLIB_NOEXCEPT {
74 #ifndef NLIB_NONNULL_ENABLED
75  if (!ptr) {
76  this->SetError(EINVAL);
77  return 0;
78  }
79 #endif
80  if (nbytes > RSIZE_MAX) { // INT01-C
81  this->SetError(EINVAL);
82  return 0;
83  }
84  if (is_buf_curidx_ + nbytes <= is_buf_endidx_) {
85  nlib_memcpy(ptr, nbytes, &is_buf_[is_buf_curidx_], nbytes);
86  is_buf_curidx_ += nbytes;
87  return nbytes;
88  }
89  return this->Read_(ptr, nbytes);
90  }
91  template<size_t N>
92  size_t Read(nlib_byte_t (&buf)[N]) NLIB_NOEXCEPT { return Read(&buf[0], N); }
93  bool Close() NLIB_NOEXCEPT;
94  NLIB_SAFE_BOOL(InputStream, errno_ == 0)
95 
96  protected:
97  void ResetBuffer(void* p, size_t nbytes) NLIB_NOEXCEPT {
98  is_buf_ = static_cast<unsigned char*>(p);
99  is_bufsize_ = static_cast<int>(nbytes);
100  }
101  void SetError(errno_t e) const NLIB_NOEXCEPT {
102  if (errno_ == 0) errno_ = e;
103  }
104 
105  private:
106  virtual size_t FillBuffer_(void* p, size_t nbytes) NLIB_NOEXCEPT = 0;
107  virtual bool Close_() NLIB_NOEXCEPT = 0;
108  virtual void* GetWorkBuffer_(size_t* nbytes) NLIB_NOEXCEPT;
109  size_t Read_(void* ptr, size_t nbytes) NLIB_NOEXCEPT;
110 
111  // By default, Skip_() reads data on is_buf_.
112  // you can override it if you can implement more efficient code.
113  virtual size_t Skip_(size_t nbytes) NLIB_NOEXCEPT;
114 
115  private:
116  void CheckBuffer() NLIB_NOEXCEPT;
117  bool GetWorkBuffer() NLIB_NOEXCEPT;
118 
119  private:
120  uint64_t pos_;
121  size_t is_buf_curidx_;
122  size_t is_buf_endidx_;
123  unsigned char* is_buf_;
124  size_t is_bufsize_;
125  mutable ErrnoT errno_;
126  // errno_ is changed only from derived classes.
127  // FillBuffer_() or Close_() changes errno_ in other words.
128 
130 };
131 
133  public:
135  virtual ~NullInputStream() NLIB_NOEXCEPT {}
136 
137  private:
138  char dummy_buf_[256];
139  virtual size_t FillBuffer_(void* p, size_t nbytes) NLIB_NOEXCEPT NLIB_OVERRIDE;
140  virtual bool Close_() NLIB_NOEXCEPT NLIB_OVERRIDE { return true; }
141  virtual size_t Skip_(size_t nbytes) NLIB_NOEXCEPT NLIB_OVERRIDE;
142 };
143 
144 namespace detail {
145 
146 template<size_t N>
147 class MiniBufIn {
148  public:
149  NLIB_STATIC_ASSERT(N >= 16);
150  static NLIB_CEXPR const size_t buf_size = N;
151  NLIB_ALWAYS_INLINE MiniBufIn() NLIB_NOEXCEPT { cur_ = end_ = &buf_[0]; }
152  template<class IS>
153  NLIB_ALWAYS_INLINE bool Prefetch(IS* stream, size_t n) NLIB_NOEXCEPT {
154  if (cur_ + n > end_) {
155  NLIB_ASSERT(n <= N);
156  size_t rem = end_ - cur_;
157  nlib_memmove(static_cast<void*>(&buf_[0]), N,
158  cur_, rem);
159  size_t nread = stream->Read(&buf_[rem], N - rem);
160  cur_ = &buf_[0];
161  end_ = &buf_[0] + rem + nread;
162  return (nread + rem >= n);
163  }
164  return true;
165  }
166  template<class IS>
167  NLIB_ALWAYS_INLINE int Peek(IS* stream) NLIB_NOEXCEPT {
168  if (NLIB_UNLIKELY(cur_ == end_)) {
169  size_t nread = stream->Read(&buf_[0], N);
170  if (NLIB_UNLIKELY(nread == 0)) return -1;
171  cur_ = &buf_[0];
172  end_ = &buf_[0] + nread;
173  }
174  return *cur_;
175  }
176  template<class IS>
177  NLIB_ALWAYS_INLINE int Read(IS* stream) NLIB_NOEXCEPT {
178  if (NLIB_UNLIKELY(cur_ == end_)) {
179  size_t nread = stream->Read(&buf_[0], N);
180  if (NLIB_UNLIKELY(nread == 0)) return -1;
181  cur_ = &buf_[0] + 1;
182  end_ = &buf_[0] + nread;
183  return buf_[0];
184  } else {
185  int c = *cur_;
186  ++cur_;
187  return c;
188  }
189  }
190 
191  NLIB_ALWAYS_INLINE void Advance(size_t n) NLIB_NOEXCEPT {
192  // Prefetch(stream, n) must be successful beforehand
193  cur_ += n;
194  }
195  NLIB_ALWAYS_INLINE const uint8_t& operator[](size_t n) NLIB_NOEXCEPT {
196  // Prefetch(stream, n + 1) must be successful beforehand
197  return cur_[n];
198  }
199  template<class IS>
201  size_t ReadBytes(IS* stream, void* data, size_t nbytes) NLIB_NOEXCEPT {
202  if (cur_ + nbytes <= end_) {
203  nlib_memcpy(data, nbytes, cur_, nbytes);
204  cur_ += nbytes;
205  return nbytes;
206  }
207  uint8_t* p = static_cast<uint8_t*>(data);
208  size_t rem = end_ - cur_;
209  nlib_memcpy(static_cast<void*>(p), nbytes, cur_, rem);
210  cur_ = end_ = &buf_[0];
211  size_t nread = stream->Read(p + rem, nbytes - rem);
212  return nread + rem;
213  }
214  template<class IS, class T>
215  size_t Read(IS* stream, T* data, size_t count) NLIB_NOEXCEPT {
216  NLIB_STATIC_ASSERT(sizeof(*data) <= N);
217  NLIB_STATIC_ASSERT(IsPod<T>::value);
218  size_t nbytes = sizeof(*data) * count;
219  size_t nread = ReadBytes(stream, data, nbytes);
220  if (NLIB_LIKELY(nread == nbytes)) return count;
221  size_t mod = nread % sizeof(*data);
222  uint8_t* p = static_cast<uint8_t*>(static_cast<void*>(data));
223  nlib_memcpy(static_cast<void*>(&buf_[0]), N,
224  p + nread - mod, mod);
225  end_ = &buf_[mod];
226  return nread / sizeof(*data);
227  }
228  NLIB_ALWAYS_INLINE size_t size() const NLIB_NOEXCEPT { return end_ - cur_; }
229 
230  private:
231  uint8_t* cur_;
232  uint8_t* end_;
233  uint8_t buf_[N];
234 };
235 
236 } // namespace detail
237 NLIB_NAMESPACE_END
238 
239 #endif // INCLUDE_NN_NLIB_INPUTSTREAM_H_
#define NLIB_OVERRIDE
Defines override if it is available for use. If not, holds an empty string.
Definition: Config.h:244
size_t Read(void *ptr, size_t nbytes) noexcept
Reads the number of bytes of data specified by nbytes into the memory region specified by ptr...
Definition: InputStream.h:73
#define NLIB_ALWAYS_INLINE
Indicates that the compiler is forced to perform inline expansion of functions.
Definition: Platform_unix.h:97
Substitute definitions for the C++11 standard header type_traits. These substitute definitions are us...
uint64_t Pos64() const noexcept
Returns the current position in the stream as a 64-bit value.
Definition: InputStream.h:47
#define NLIB_DISALLOW_COPY_AND_ASSIGN(TypeName)
Prohibits use of the copy constructor and assignment operator for the class specified by TypeName...
Definition: Config.h:179
#define NLIB_SAFE_BOOL(class_name, exp)
Defines a safe operator bool function in the class. Uses the C++11 explicit bool if it is available f...
Definition: Config.h:194
errno_t GetErrorValue() const noexcept
Gets the error value.
Definition: InputStream.h:44
bool IsEos() noexcept
Returns true if the stream is finished being read through to the end. If the stream has not been read...
Definition: InputStream.h:48
#define NLIB_CHECK_RESULT
Indicates that the caller of the function must check the returned value.
int Read() noexcept
Reads one byte of data from the stream.
Definition: InputStream.h:56
#define NLIB_UNLIKELY(x)
Indicates to the compiler that condition x is likely to be false.
#define RSIZE_MAX
Defines a value somewhat smaller than the maximum value of size_t.
Definition: Platform.h:224
void ResetBuffer(void *p, size_t nbytes) noexcept
Sets the buffer held by InputStream.
Definition: InputStream.h:97
#define NLIB_VIS_PUBLIC
Symbols for functions and classes are made available outside of the library.
Definition: Platform_unix.h:89
size_t Pos() const noexcept
Returns the current position in the stream.
Definition: InputStream.h:46
virtual ~InputStream() noexcept
Destructor. This function is called from the derived class.
Definition: InputStream.h:37
#define NLIB_LIKELY(x)
Indicates to the compiler that condition x is likely to be true.
Definition: Platform_unix.h:99
constexpr InputStream() noexcept
Instantiates the object. This function is called from the derived class.
Definition: InputStream.h:31
The base class for input streams. This class cannot be instantiated.
Definition: InputStream.h:29
Class that wraps errno_t. This class improves visual representations in the Visual Studio debugger...
Definition: Config.h:406
static errno_t nlib_memcpy(void *s1, size_t s1max, const void *s2, size_t n)
An implementation corresponding to N1078 memcpy_s.
Definition: Platform.h:2437
int Peek() noexcept
Reads the next byte without consuming the stream.
Definition: InputStream.h:64
#define NLIB_NOEXCEPT
Defines noexcept geared to the environment, or the equivalent.
Definition: Config.h:105
#define NLIB_CEXPR
Defines constexpr if it is available for use. If not, holds an empty string.
Definition: Config.h:107
A file that contains the configuration information for each development environment.
void SetError(errno_t e) const noexcept
Sets an error to InputStream.
Definition: InputStream.h:101
#define NLIB_FINAL
Defines final if it is available for use. If not, holds an empty string.
Definition: Config.h:245
#define NLIB_STATIC_ASSERT(exp)
Defines a static assertion. Uses static_assert if it is available for use.
Definition: Config.h:170
bool Read(BinaryReader *r, T *x)
You can read to user-defined class objects by specializing this function template.
Definition: BinaryReader.h:172
The class for streams that always load 0.
Definition: InputStream.h:132
unsigned char nlib_byte_t
This type will be defined as std::byte in a typedef of C++17 or later.
Definition: Platform.h:319
static errno_t nlib_memmove(void *s1, size_t s1max, const void *s2, size_t n)
An implementation corresponding to N1078 memmove_s.
Definition: Platform.h:2455
int errno_t
Indicates with an int-type typedef that a POSIX error value is returned as the return value...
Definition: NMalloc.h:37