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/thirdparty/libpng/pngwio.c

http://crashrpt.googlecode.com/
C | 228 lines | 156 code | 17 blank | 55 comment | 33 complexity | d50d409252a32096f56bb6da41c68f49 MD5 | raw file
  1
  2/* pngwio.c - functions for data output
  3 *
  4 * libpng 1.2.7 - September 12, 2004
  5 * For conditions of distribution and use, see copyright notice in png.h
  6 * Copyright (c) 1998-2004 Glenn Randers-Pehrson
  7 * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
  8 * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
  9 *
 10 * This file provides a location for all output.  Users who need
 11 * special handling are expected to write functions that have the same
 12 * arguments as these and perform similar functions, but that possibly
 13 * use different output methods.  Note that you shouldn't change these
 14 * functions, but rather write replacement functions and then change
 15 * them at run time with png_set_write_fn(...).
 16 */
 17
 18#define PNG_INTERNAL
 19#include "png.h"
 20#ifdef PNG_WRITE_SUPPORTED
 21
 22/* Write the data to whatever output you are using.  The default routine
 23   writes to a file pointer.  Note that this routine sometimes gets called
 24   with very small lengths, so you should implement some kind of simple
 25   buffering if you are using unbuffered writes.  This should never be asked
 26   to write more than 64K on a 16 bit machine.  */
 27
 28void /* PRIVATE */
 29png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 30{
 31   if (png_ptr->write_data_fn != NULL )
 32      (*(png_ptr->write_data_fn))(png_ptr, data, length);
 33   else
 34      png_error(png_ptr, "Call to NULL write function");
 35}
 36
 37#if !defined(PNG_NO_STDIO)
 38/* This is the function that does the actual writing of data.  If you are
 39   not writing to a standard C stream, you should create a replacement
 40   write_data function and use it at run time with png_set_write_fn(), rather
 41   than changing the library. */
 42#ifndef USE_FAR_KEYWORD
 43void PNGAPI
 44png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 45{
 46   png_uint_32 check;
 47
 48#if defined(_WIN32_WCE)
 49   if ( !WriteFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
 50      check = 0;
 51#else
 52   check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
 53#endif
 54   if (check != length)
 55      png_error(png_ptr, "Write Error");
 56}
 57#else
 58/* this is the model-independent version. Since the standard I/O library
 59   can't handle far buffers in the medium and small models, we have to copy
 60   the data.
 61*/
 62
 63#define NEAR_BUF_SIZE 1024
 64#define MIN(a,b) (a <= b ? a : b)
 65
 66void PNGAPI
 67png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
 68{
 69   png_uint_32 check;
 70   png_byte *near_data;  /* Needs to be "png_byte *" instead of "png_bytep" */
 71   png_FILE_p io_ptr;
 72
 73   /* Check if data really is near. If so, use usual code. */
 74   near_data = (png_byte *)CVT_PTR_NOCHECK(data);
 75   io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
 76   if ((png_bytep)near_data == data)
 77   {
 78#if defined(_WIN32_WCE)
 79      if ( !WriteFile(io_ptr, near_data, length, &check, NULL) )
 80         check = 0;
 81#else
 82      check = fwrite(near_data, 1, length, io_ptr);
 83#endif
 84   }
 85   else
 86   {
 87      png_byte buf[NEAR_BUF_SIZE];
 88      png_size_t written, remaining, err;
 89      check = 0;
 90      remaining = length;
 91      do
 92      {
 93         written = MIN(NEAR_BUF_SIZE, remaining);
 94         png_memcpy(buf, data, written); /* copy far buffer to near buffer */
 95#if defined(_WIN32_WCE)
 96         if ( !WriteFile(io_ptr, buf, written, &err, NULL) )
 97            err = 0;
 98#else
 99         err = fwrite(buf, 1, written, io_ptr);
100#endif
101         if (err != written)
102            break;
103         else
104            check += err;
105         data += written;
106         remaining -= written;
107      }
108      while (remaining != 0);
109   }
110   if (check != length)
111      png_error(png_ptr, "Write Error");
112}
113
114#endif
115#endif
116
117/* This function is called to output any data pending writing (normally
118   to disk).  After png_flush is called, there should be no data pending
119   writing in any buffers. */
120#if defined(PNG_WRITE_FLUSH_SUPPORTED)
121void /* PRIVATE */
122png_flush(png_structp png_ptr)
123{
124   if (png_ptr->output_flush_fn != NULL)
125      (*(png_ptr->output_flush_fn))(png_ptr);
126}
127
128#if !defined(PNG_NO_STDIO)
129void PNGAPI
130png_default_flush(png_structp png_ptr)
131{
132#if !defined(_WIN32_WCE)
133   png_FILE_p io_ptr;
134   io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));
135   if (io_ptr != NULL)
136      fflush(io_ptr);
137#endif
138}
139#endif
140#endif
141
142/* This function allows the application to supply new output functions for
143   libpng if standard C streams aren't being used.
144
145   This function takes as its arguments:
146   png_ptr       - pointer to a png output data structure
147   io_ptr        - pointer to user supplied structure containing info about
148                   the output functions.  May be NULL.
149   write_data_fn - pointer to a new output function that takes as its
150                   arguments a pointer to a png_struct, a pointer to
151                   data to be written, and a 32-bit unsigned int that is
152                   the number of bytes to be written.  The new write
153                   function should call png_error(png_ptr, "Error msg")
154                   to exit and output any fatal error messages.
155   flush_data_fn - pointer to a new flush function that takes as its
156                   arguments a pointer to a png_struct.  After a call to
157                   the flush function, there should be no data in any buffers
158                   or pending transmission.  If the output method doesn't do
159                   any buffering of ouput, a function prototype must still be
160                   supplied although it doesn't have to do anything.  If
161                   PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
162                   time, output_flush_fn will be ignored, although it must be
163                   supplied for compatibility. */
164void PNGAPI
165png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
166   png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
167{
168   png_ptr->io_ptr = io_ptr;
169
170#if !defined(PNG_NO_STDIO)
171   if (write_data_fn != NULL)
172      png_ptr->write_data_fn = write_data_fn;
173   else
174      png_ptr->write_data_fn = png_default_write_data;
175#else
176   png_ptr->write_data_fn = write_data_fn;
177#endif
178
179#if defined(PNG_WRITE_FLUSH_SUPPORTED)
180#if !defined(PNG_NO_STDIO)
181   if (output_flush_fn != NULL)
182      png_ptr->output_flush_fn = output_flush_fn;
183   else
184      png_ptr->output_flush_fn = png_default_flush;
185#else
186   png_ptr->output_flush_fn = output_flush_fn;
187#endif
188#endif /* PNG_WRITE_FLUSH_SUPPORTED */
189
190   /* It is an error to read while writing a png file */
191   if (png_ptr->read_data_fn != NULL)
192   {
193      png_ptr->read_data_fn = NULL;
194      png_warning(png_ptr,
195         "Attempted to set both read_data_fn and write_data_fn in");
196      png_warning(png_ptr,
197         "the same structure.  Resetting read_data_fn to NULL.");
198   }
199}
200
201#if defined(USE_FAR_KEYWORD)
202#if defined(_MSC_VER)
203void *png_far_to_near(png_structp png_ptr,png_voidp ptr, int check)
204{
205   void *near_ptr;
206   void FAR *far_ptr;
207   FP_OFF(near_ptr) = FP_OFF(ptr);
208   far_ptr = (void FAR *)near_ptr;
209   if(check != 0)
210      if(FP_SEG(ptr) != FP_SEG(far_ptr))
211         png_error(png_ptr,"segment lost in conversion");
212   return(near_ptr);
213}
214#  else
215void *png_far_to_near(png_structp png_ptr,png_voidp ptr, int check)
216{
217   void *near_ptr;
218   void FAR *far_ptr;
219   near_ptr = (void FAR *)ptr;
220   far_ptr = (void FAR *)near_ptr;
221   if(check != 0)
222      if(far_ptr != ptr)
223         png_error(png_ptr,"segment lost in conversion");
224   return(near_ptr);
225}
226#   endif
227#   endif
228#endif /* PNG_WRITE_SUPPORTED */