Visualization Library 2.0.0-b5

A lightweight C++ OpenGL middleware for 2D/3D graphics

VL     Star     Watch     Fork     Issue

[Download] [Tutorials] [All Classes] [Grouped Classes]
pngwio.c
Go to the documentation of this file.
1 
2 /* pngwio.c - functions for data output
3  *
4  * Last changed in libpng 1.2.41 [December 3, 2009]
5  * Copyright (c) 1998-2002,2004,2006-209 Glenn Randers-Pehrson
6  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
7  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
8  *
9  * This code is released under the libpng license.
10  * For conditions of distribution and use, see the disclaimer
11  * and license in png.h
12  *
13  * This file provides a location for all output. Users who need
14  * special handling are expected to write functions that have the same
15  * arguments as these and perform similar functions, but that possibly
16  * use different output methods. Note that you shouldn't change these
17  * functions, but rather write replacement functions and then change
18  * them at run time with png_set_write_fn(...).
19  */
20 
21 #define PNG_INTERNAL
22 #define PNG_NO_PEDANTIC_WARNINGS
23 #include "png.h"
24 #ifdef PNG_WRITE_SUPPORTED
25 
26 /* Write the data to whatever output you are using. The default routine
27  * writes to a file pointer. Note that this routine sometimes gets called
28  * with very small lengths, so you should implement some kind of simple
29  * buffering if you are using unbuffered writes. This should never be asked
30  * to write more than 64K on a 16 bit machine.
31  */
32 
33 void /* PRIVATE */
35 {
36  if (png_ptr->write_data_fn != NULL )
37  (*(png_ptr->write_data_fn))(png_ptr, data, length);
38  else
39  png_error(png_ptr, "Call to NULL write function");
40 }
41 
42 #ifdef PNG_STDIO_SUPPORTED
43 /* This is the function that does the actual writing of data. If you are
44  * not writing to a standard C stream, you should create a replacement
45  * write_data function and use it at run time with png_set_write_fn(), rather
46  * than changing the library.
47  */
48 #ifndef USE_FAR_KEYWORD
49 void PNGAPI
51 {
52  png_uint_32 check;
53 
54  if (png_ptr == NULL)
55  return;
56 #ifdef _WIN32_WCE
57  if ( !WriteFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
58  check = 0;
59 #else
60  check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
61 #endif
62  if (check != length)
63  png_error(png_ptr, "Write Error");
64 }
65 #else
66 /* This is the model-independent version. Since the standard I/O library
67  * can't handle far buffers in the medium and small models, we have to copy
68  * the data.
69  */
70 
71 #define NEAR_BUF_SIZE 1024
72 #define MIN(a,b) (a <= b ? a : b)
73 
74 void PNGAPI
76 {
77  png_uint_32 check;
78  png_byte *near_data; /* Needs to be "png_byte *" instead of "png_bytep" */
80 
81  if (png_ptr == NULL)
82  return;
83  /* Check if data really is near. If so, use usual code. */
84  near_data = (png_byte *)CVT_PTR_NOCHECK(data);
85  io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
86  if ((png_bytep)near_data == data)
87  {
88 #ifdef _WIN32_WCE
89  if ( !WriteFile(io_ptr, near_data, length, &check, NULL) )
90  check = 0;
91 #else
92  check = fwrite(near_data, 1, length, io_ptr);
93 #endif
94  }
95  else
96  {
97  png_byte buf[NEAR_BUF_SIZE];
98  png_size_t written, remaining, err;
99  check = 0;
100  remaining = length;
101  do
102  {
103  written = MIN(NEAR_BUF_SIZE, remaining);
104  png_memcpy(buf, data, written); /* Copy far buffer to near buffer */
105 #ifdef _WIN32_WCE
106  if ( !WriteFile(io_ptr, buf, written, &err, NULL) )
107  err = 0;
108 #else
109  err = fwrite(buf, 1, written, io_ptr);
110 #endif
111  if (err != written)
112  break;
113 
114  else
115  check += err;
116 
117  data += written;
118  remaining -= written;
119  }
120  while (remaining != 0);
121  }
122  if (check != length)
123  png_error(png_ptr, "Write Error");
124 }
125 
126 #endif
127 #endif
128 
129 /* This function is called to output any data pending writing (normally
130  * to disk). After png_flush is called, there should be no data pending
131  * writing in any buffers.
132  */
133 #ifdef PNG_WRITE_FLUSH_SUPPORTED
134 void /* PRIVATE */
136 {
137  if (png_ptr->output_flush_fn != NULL)
138  (*(png_ptr->output_flush_fn))(png_ptr);
139 }
140 
141 #ifdef PNG_STDIO_SUPPORTED
142 void PNGAPI
144 {
145 #ifndef _WIN32_WCE
147 #endif
148  if (png_ptr == NULL)
149  return;
150 #ifndef _WIN32_WCE
151  io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));
152  fflush(io_ptr);
153 #endif
154 }
155 #endif
156 #endif
157 
158 /* This function allows the application to supply new output functions for
159  * libpng if standard C streams aren't being used.
160  *
161  * This function takes as its arguments:
162  * png_ptr - pointer to a png output data structure
163  * io_ptr - pointer to user supplied structure containing info about
164  * the output functions. May be NULL.
165  * write_data_fn - pointer to a new output function that takes as its
166  * arguments a pointer to a png_struct, a pointer to
167  * data to be written, and a 32-bit unsigned int that is
168  * the number of bytes to be written. The new write
169  * function should call png_error(png_ptr, "Error msg")
170  * to exit and output any fatal error messages. May be
171  * NULL, in which case libpng's default function will
172  * be used.
173  * flush_data_fn - pointer to a new flush function that takes as its
174  * arguments a pointer to a png_struct. After a call to
175  * the flush function, there should be no data in any buffers
176  * or pending transmission. If the output method doesn't do
177  * any buffering of output, a function prototype must still be
178  * supplied although it doesn't have to do anything. If
179  * PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
180  * time, output_flush_fn will be ignored, although it must be
181  * supplied for compatibility. May be NULL, in which case
182  * libpng's default function will be used, if
183  * PNG_WRITE_FLUSH_SUPPORTED is defined. This is not
184  * a good idea if io_ptr does not point to a standard
185  * *FILE structure.
186  */
187 void PNGAPI
189  png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
190 {
191  if (png_ptr == NULL)
192  return;
193 
194  png_ptr->io_ptr = io_ptr;
195 
196 #ifdef PNG_STDIO_SUPPORTED
197  if (write_data_fn != NULL)
198  png_ptr->write_data_fn = write_data_fn;
199 
200  else
201  png_ptr->write_data_fn = png_default_write_data;
202 #else
203  png_ptr->write_data_fn = write_data_fn;
204 #endif
205 
206 #ifdef PNG_WRITE_FLUSH_SUPPORTED
207 #ifdef PNG_STDIO_SUPPORTED
208  if (output_flush_fn != NULL)
209  png_ptr->output_flush_fn = output_flush_fn;
210 
211  else
212  png_ptr->output_flush_fn = png_default_flush;
213 #else
214  png_ptr->output_flush_fn = output_flush_fn;
215 #endif
216 #endif /* PNG_WRITE_FLUSH_SUPPORTED */
217 
218  /* It is an error to read while writing a png file */
219  if (png_ptr->read_data_fn != NULL)
220  {
221  png_ptr->read_data_fn = NULL;
222  png_warning(png_ptr,
223  "Attempted to set both read_data_fn and write_data_fn in");
224  png_warning(png_ptr,
225  "the same structure. Resetting read_data_fn to NULL.");
226  }
227 }
228 
229 #ifdef USE_FAR_KEYWORD
230 #ifdef _MSC_VER
231 void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)
232 {
233  void *near_ptr;
234  void FAR *far_ptr;
235  FP_OFF(near_ptr) = FP_OFF(ptr);
236  far_ptr = (void FAR *)near_ptr;
237 
238  if (check != 0)
239  if (FP_SEG(ptr) != FP_SEG(far_ptr))
240  png_error(png_ptr, "segment lost in conversion");
241 
242  return(near_ptr);
243 }
244 # else
245 void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)
246 {
247  void *near_ptr;
248  void FAR *far_ptr;
249  near_ptr = (void FAR *)ptr;
250  far_ptr = (void FAR *)near_ptr;
251 
252  if (check != 0)
253  if (far_ptr != ptr)
254  png_error(png_ptr, "segment lost in conversion");
255 
256  return(near_ptr);
257 }
258 # endif
259 # endif
260 #endif /* PNG_WRITE_SUPPORTED */
GLenum GLuint GLenum GLsizei length
void PNGAPI png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
Definition: pngwio.c:50
#define NULL
Definition: ftobjs.h:61
png_voidp png_rw_ptr write_data_fn
Definition: png.h:1819
png_voidp ptr
Definition: png.h:1908
png_byte FAR * png_bytep
Definition: pngconf.h:1328
#define MIN(a, b)
Definition: jpegint.h:269
void PNGAPI png_set_write_fn(png_structp png_ptr, png_voidp io_ptr, png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
Definition: pngwio.c:188
void png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
Definition: pngwio.c:34
#define CVT_PTR_NOCHECK(ptr)
Definition: pngconf.h:1636
GLenum GLuint GLenum GLsizei const GLchar * buf
void png_flush(png_structp png_ptr)
Definition: pngwio.c:135
void PNGAPI png_default_flush(png_structp png_ptr)
Definition: pngwio.c:143
#define PNGAPI
Definition: pngconf.h:1517
png_struct FAR * png_structp
Definition: png.h:973
#define png_error(s1, s2)
Definition: pngusr.h:25
png_voidp png_rw_ptr png_flush_ptr output_flush_fn
Definition: png.h:1819
unsigned char png_byte
Definition: pngconf.h:1251
#define png_memcpy
Definition: pngconf.h:1661
GLsizei GLsizei GLenum GLenum const GLvoid * data
void PNGAPI png_warning(png_structp png_ptr, png_const_charp warning_message)
Definition: pngerror.c:111
#define FAR
Definition: zconf.h:215
png_voidp io_ptr
Definition: png.h:1819
void FAR * png_voidp
Definition: pngconf.h:1327
size_t png_size_t
Definition: pngconf.h:1259
unsigned long png_uint_32
Definition: pngconf.h:1247
FILE * png_FILE_p
Definition: pngconf.h:1341
#define CVT_PTR(ptr)
Definition: pngconf.h:1635