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ImfIO.h
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34 
35 
36 #ifndef INCLUDED_IMF_IO_H
37 #define INCLUDED_IMF_IO_H
38 
39 //-----------------------------------------------------------------------------
40 //
41 // Low-level file input and output for OpenEXR.
42 //
43 //-----------------------------------------------------------------------------
44 
45 #include "ImfInt64.h"
46 #include "ImfNamespace.h"
47 #include "ImfExport.h"
48 
49 #include <string>
50 
51 
53 
54 //-----------------------------------------------------------
55 // class IStream -- an abstract base class for input streams.
56 //-----------------------------------------------------------
57 
58 class IStream
59 {
60  public:
61 
62  //-----------
63  // Destructor
64  //-----------
65 
67  virtual ~IStream ();
68 
69 
70  //-------------------------------------------------
71  // Does this input stream support memory-mapped IO?
72  //
73  // Memory-mapped streams can avoid an extra copy;
74  // memory-mapped read operations return a pointer
75  // to an internal buffer instead of copying data
76  // into a buffer supplied by the caller.
77  //-------------------------------------------------
78 
80  virtual bool isMemoryMapped () const;
81 
82 
83  //------------------------------------------------------
84  // Read from the stream:
85  //
86  // read(c,n) reads n bytes from the stream, and stores
87  // them in array c. If the stream contains less than n
88  // bytes, or if an I/O error occurs, read(c,n) throws
89  // an exception. If read(c,n) reads the last byte from
90  // the file it returns false, otherwise it returns true.
91  //------------------------------------------------------
92 
93  virtual bool read (char c[/*n*/], int n) = 0;
94 
95 
96  //---------------------------------------------------
97  // Read from a memory-mapped stream:
98  //
99  // readMemoryMapped(n) reads n bytes from the stream
100  // and returns a pointer to the first byte. The
101  // returned pointer remains valid until the stream
102  // is closed. If there are less than n byte left to
103  // read in the stream or if the stream is not memory-
104  // mapped, readMemoryMapped(n) throws an exception.
105  //---------------------------------------------------
106 
107  IMF_EXPORT
108  virtual char * readMemoryMapped (int n);
109 
110 
111  //--------------------------------------------------------
112  // Get the current reading position, in bytes from the
113  // beginning of the file. If the next call to read() will
114  // read the first byte in the file, tellg() returns 0.
115  //--------------------------------------------------------
116 
117  virtual Int64 tellg () = 0;
118 
119 
120  //-------------------------------------------
121  // Set the current reading position.
122  // After calling seekg(i), tellg() returns i.
123  //-------------------------------------------
124 
125  virtual void seekg (Int64 pos) = 0;
126 
127 
128  //------------------------------------------------------
129  // Clear error conditions after an operation has failed.
130  //------------------------------------------------------
131 
132  IMF_EXPORT
133  virtual void clear ();
134 
135 
136  //------------------------------------------------------
137  // Get the name of the file associated with this stream.
138  //------------------------------------------------------
139 
140  IMF_EXPORT
141  const char * fileName () const;
142 
143  protected:
144 
145  IMF_EXPORT
146  IStream (const char fileName[]);
147 
148  private:
149 
150  IStream (const IStream &); // not implemented
151  IStream & operator = (const IStream &); // not implemented
152 
153  std::string _fileName;
154 };
155 
156 
157 //-----------------------------------------------------------
158 // class OStream -- an abstract base class for output streams
159 //-----------------------------------------------------------
160 
161 class OStream
162 {
163  public:
164 
165  //-----------
166  // Destructor
167  //-----------
168 
169  IMF_EXPORT
170  virtual ~OStream ();
171 
172 
173  //----------------------------------------------------------
174  // Write to the stream:
175  //
176  // write(c,n) takes n bytes from array c, and stores them
177  // in the stream. If an I/O error occurs, write(c,n) throws
178  // an exception.
179  //----------------------------------------------------------
180 
181  virtual void write (const char c[/*n*/], int n) = 0;
182 
183 
184  //---------------------------------------------------------
185  // Get the current writing position, in bytes from the
186  // beginning of the file. If the next call to write() will
187  // start writing at the beginning of the file, tellp()
188  // returns 0.
189  //---------------------------------------------------------
190 
191  virtual Int64 tellp () = 0;
192 
193 
194  //-------------------------------------------
195  // Set the current writing position.
196  // After calling seekp(i), tellp() returns i.
197  //-------------------------------------------
198 
199  virtual void seekp (Int64 pos) = 0;
200 
201 
202  //------------------------------------------------------
203  // Get the name of the file associated with this stream.
204  //------------------------------------------------------
205 
206  IMF_EXPORT
207  const char * fileName () const;
208 
209  protected:
210 
211  IMF_EXPORT
212  OStream (const char fileName[]);
213 
214  private:
215 
216  OStream (const OStream &); // not implemented
217  OStream & operator = (const OStream &); // not implemented
218 
219  std::string _fileName;
220 };
221 
222 
223 //-----------------------
224 // Helper classes for Xdr
225 //-----------------------
226 
227 struct StreamIO
228 {
229  static void
230  writeChars (OStream &os, const char c[/*n*/], int n)
231  {
232  os.write (c, n);
233  }
234 
235  static bool
236  readChars (IStream &is, char c[/*n*/], int n)
237  {
238  return is.read (c, n);
239  }
240 };
241 
242 
243 struct CharPtrIO
244 {
245  static void
246  writeChars (char *&op, const char c[/*n*/], int n)
247  {
248  while (n--)
249  *op++ = *c++;
250  }
251 
252  static bool
253  readChars (const char *&ip, char c[/*n*/], int n)
254  {
255  while (n--)
256  *c++ = *ip++;
257 
258  return true;
259  }
260 };
261 
263 
264 #endif
static void writeChars(OStream &os, const char c[], int n)
Definition: ImfIO.h:230
Definition: ImfIO.h:58
IMF_EXPORT OStream(const char fileName[])
IMF_EXPORT const char * fileName() const
#define OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT
Definition: ImfNamespace.h:109
virtual IMF_EXPORT ~OStream()
const GLfloat * c
Definition: glew.h:16631
static bool readChars(IStream &is, char c[], int n)
Definition: ImfIO.h:236
Definition: ImfIO.h:161
virtual void seekg(Int64 pos)=0
virtual void write(const char c[], int n)=0
virtual bool read(char c[], int n)=0
virtual void seekp(Int64 pos)=0
virtual Int64 tellg()=0
static bool readChars(const char *&ip, char c[], int n)
Definition: ImfIO.h:253
IMF_EXPORT IStream(const char fileName[])
IMATH_INTERNAL_NAMESPACE_HEADER_ENTER typedef long long unsigned int Int64
Definition: ImathInt64.h:58
GLsizei const GLchar *const * string
Definition: glcorearb.h:813
#define IMF_EXPORT
Definition: ImfExport.h:44
static void writeChars(char *&op, const char c[], int n)
Definition: ImfIO.h:246
virtual IMF_EXPORT char * readMemoryMapped(int n)
GLdouble n
Definition: glcorearb.h:2007
virtual IMF_EXPORT ~IStream()
#define OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER
Definition: ImfNamespace.h:108
IMF_EXPORT const char * fileName() const
virtual IMF_EXPORT bool isMemoryMapped() const
virtual Int64 tellp()=0
virtual IMF_EXPORT void clear()