/[pcsx2_0.9.7]/trunk/3rdparty/wxWidgets/src/png/pngrio.c
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Contents of /trunk/3rdparty/wxWidgets/src/png/pngrio.c

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Revision 31 - (show annotations) (download)
Tue Sep 7 03:24:11 2010 UTC (10 years, 2 months ago) by william
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committing r3113 initial commit again...
1
2 /* pngrio.c - functions for data input
3 *
4 * Last changed in libpng 1.2.37 [June 4, 2009]
5 * Copyright (c) 1998-2009 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 input. Users who need
14 * special handling are expected to write a function that has the same
15 * arguments as this and performs a similar function, but that possibly
16 * has a different input method. Note that you shouldn't change this
17 * function, but rather write a replacement function and then make
18 * libpng use it at run time with png_set_read_fn(...).
19 */
20
21 #define PNG_INTERNAL
22 #include "png.h"
23 #if defined(PNG_READ_SUPPORTED)
24
25 /* Read the data from whatever input you are using. The default routine
26 * reads from a file pointer. Note that this routine sometimes gets called
27 * with very small lengths, so you should implement some kind of simple
28 * buffering if you are using unbuffered reads. This should never be asked
29 * to read more then 64K on a 16 bit machine.
30 */
31 void /* PRIVATE */
32 png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
33 {
34 png_debug1(4, "reading %d bytes", (int)length);
35 if (png_ptr->read_data_fn != NULL)
36 (*(png_ptr->read_data_fn))(png_ptr, data, length);
37 else
38 png_error(png_ptr, "Call to NULL read function");
39 }
40
41 #if !defined(PNG_NO_STDIO)
42 /* This is the function that does the actual reading of data. If you are
43 * not reading from a standard C stream, you should create a replacement
44 * read_data function and use it at run time with png_set_read_fn(), rather
45 * than changing the library.
46 */
47 #ifndef USE_FAR_KEYWORD
48 void PNGAPI
49 png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
50 {
51 png_size_t check;
52
53 if (png_ptr == NULL)
54 return;
55 /* fread() returns 0 on error, so it is OK to store this in a png_size_t
56 * instead of an int, which is what fread() actually returns.
57 */
58 #if defined(_WIN32_WCE)
59 if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
60 check = 0;
61 #else
62 check = (png_size_t)fread(data, (png_size_t)1, length,
63 (png_FILE_p)png_ptr->io_ptr);
64 #endif
65
66 if (check != length)
67 png_error(png_ptr, "Read Error");
68 }
69 #else
70 /* This is the model-independent version. Since the standard I/O library
71 can't handle far buffers in the medium and small models, we have to copy
72 the data.
73 */
74
75 #define NEAR_BUF_SIZE 1024
76 #define MIN(a,b) (a <= b ? a : b)
77
78 static void PNGAPI
79 png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
80 {
81 int check;
82 png_byte *n_data;
83 png_FILE_p io_ptr;
84
85 if (png_ptr == NULL)
86 return;
87 /* Check if data really is near. If so, use usual code. */
88 n_data = (png_byte *)CVT_PTR_NOCHECK(data);
89 io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
90 if ((png_bytep)n_data == data)
91 {
92 #if defined(_WIN32_WCE)
93 if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
94 check = 0;
95 #else
96 check = fread(n_data, 1, length, io_ptr);
97 #endif
98 }
99 else
100 {
101 png_byte buf[NEAR_BUF_SIZE];
102 png_size_t read, remaining, err;
103 check = 0;
104 remaining = length;
105 do
106 {
107 read = MIN(NEAR_BUF_SIZE, remaining);
108 #if defined(_WIN32_WCE)
109 if ( !ReadFile((HANDLE)(io_ptr), buf, read, &err, NULL) )
110 err = 0;
111 #else
112 err = fread(buf, (png_size_t)1, read, io_ptr);
113 #endif
114 png_memcpy(data, buf, read); /* copy far buffer to near buffer */
115 if (err != read)
116 break;
117 else
118 check += err;
119 data += read;
120 remaining -= read;
121 }
122 while (remaining != 0);
123 }
124 if ((png_uint_32)check != (png_uint_32)length)
125 png_error(png_ptr, "read Error");
126 }
127 #endif
128 #endif
129
130 /* This function allows the application to supply a new input function
131 * for libpng if standard C streams aren't being used.
132 *
133 * This function takes as its arguments:
134 * png_ptr - pointer to a png input data structure
135 * io_ptr - pointer to user supplied structure containing info about
136 * the input functions. May be NULL.
137 * read_data_fn - pointer to a new input function that takes as its
138 * arguments a pointer to a png_struct, a pointer to
139 * a location where input data can be stored, and a 32-bit
140 * unsigned int that is the number of bytes to be read.
141 * To exit and output any fatal error messages the new write
142 * function should call png_error(png_ptr, "Error msg").
143 * May be NULL, in which case libpng's default function will
144 * be used.
145 */
146 void PNGAPI
147 png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
148 png_rw_ptr read_data_fn)
149 {
150 if (png_ptr == NULL)
151 return;
152 png_ptr->io_ptr = io_ptr;
153
154 #if !defined(PNG_NO_STDIO)
155 if (read_data_fn != NULL)
156 png_ptr->read_data_fn = read_data_fn;
157 else
158 png_ptr->read_data_fn = png_default_read_data;
159 #else
160 png_ptr->read_data_fn = read_data_fn;
161 #endif
162
163 /* It is an error to write to a read device */
164 if (png_ptr->write_data_fn != NULL)
165 {
166 png_ptr->write_data_fn = NULL;
167 png_warning(png_ptr,
168 "It's an error to set both read_data_fn and write_data_fn in the ");
169 png_warning(png_ptr,
170 "same structure. Resetting write_data_fn to NULL.");
171 }
172
173 #if defined(PNG_WRITE_FLUSH_SUPPORTED)
174 png_ptr->output_flush_fn = NULL;
175 #endif
176 }
177 #endif /* PNG_READ_SUPPORTED */

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