+ − /* pngwio.c - functions for data output+ −
*+ −
* Last changed in libpng 1.2.37 [June 4, 2009]+ −
* Copyright (c) 1998-2009 Glenn Randers-Pehrson+ −
* (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)+ −
* (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)+ −
*+ −
* This code is released under the libpng license.+ −
* For conditions of distribution and use, see the disclaimer+ −
* and license in png.h+ −
*+ −
* This file provides a location for all output. Users who need+ −
* special handling are expected to write functions that have the same+ −
* arguments as these and perform similar functions, but that possibly+ −
* use different output methods. Note that you shouldn't change these+ −
* functions, but rather write replacement functions and then change+ −
* them at run time with png_set_write_fn(...).+ −
*/+ −
+ − #define PNG_INTERNAL+ −
#include "png.h"+ −
#ifdef PNG_WRITE_SUPPORTED+ −
+ − /* Write the data to whatever output you are using. The default routine+ −
* writes to a file pointer. Note that this routine sometimes gets called+ −
* with very small lengths, so you should implement some kind of simple+ −
* buffering if you are using unbuffered writes. This should never be asked+ −
* to write more than 64K on a 16 bit machine.+ −
*/+ −
+ − void /* PRIVATE */+ −
png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)+ −
{+ −
if (png_ptr->write_data_fn != NULL )+ −
(*(png_ptr->write_data_fn))(png_ptr, data, length);+ −
else+ −
png_error(png_ptr, "Call to NULL write function");+ −
}+ −
+ − #if !defined(PNG_NO_STDIO)+ −
/* This is the function that does the actual writing of data. If you are+ −
* not writing to a standard C stream, you should create a replacement+ −
* write_data function and use it at run time with png_set_write_fn(), rather+ −
* than changing the library.+ −
*/+ −
#ifndef USE_FAR_KEYWORD+ −
void PNGAPI+ −
png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)+ −
{+ −
png_uint_32 check;+ −
+ − if (png_ptr == NULL)+ −
return;+ −
#if defined(_WIN32_WCE)+ −
if ( !WriteFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )+ −
check = 0;+ −
#else+ −
check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));+ −
#endif+ −
if (check != length)+ −
png_error(png_ptr, "Write Error");+ −
}+ −
#else+ −
/* This is the model-independent version. Since the standard I/O library+ −
* can't handle far buffers in the medium and small models, we have to copy+ −
* the data.+ −
*/+ −
+ − #define NEAR_BUF_SIZE 1024+ −
#define MIN(a,b) (a <= b ? a : b)+ −
+ − void PNGAPI+ −
png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)+ −
{+ −
png_uint_32 check;+ −
png_byte *near_data; /* Needs to be "png_byte *" instead of "png_bytep" */+ −
png_FILE_p io_ptr;+ −
+ − if (png_ptr == NULL)+ −
return;+ −
/* Check if data really is near. If so, use usual code. */+ −
near_data = (png_byte *)CVT_PTR_NOCHECK(data);+ −
io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);+ −
if ((png_bytep)near_data == data)+ −
{+ −
#if defined(_WIN32_WCE)+ −
if ( !WriteFile(io_ptr, near_data, length, &check, NULL) )+ −
check = 0;+ −
#else+ −
check = fwrite(near_data, 1, length, io_ptr);+ −
#endif+ −
}+ −
else+ −
{+ −
png_byte buf[NEAR_BUF_SIZE];+ −
png_size_t written, remaining, err;+ −
check = 0;+ −
remaining = length;+ −
do+ −
{+ −
written = MIN(NEAR_BUF_SIZE, remaining);+ −
png_memcpy(buf, data, written); /* Copy far buffer to near buffer */+ −
#if defined(_WIN32_WCE)+ −
if ( !WriteFile(io_ptr, buf, written, &err, NULL) )+ −
err = 0;+ −
#else+ −
err = fwrite(buf, 1, written, io_ptr);+ −
#endif+ −
if (err != written)+ −
break;+ −
+ − else+ −
check += err;+ −
+ − data += written;+ −
remaining -= written;+ −
}+ −
while (remaining != 0);+ −
}+ −
if (check != length)+ −
png_error(png_ptr, "Write Error");+ −
}+ −
+ − #endif+ −
#endif+ −
+ − /* This function is called to output any data pending writing (normally+ −
* to disk). After png_flush is called, there should be no data pending+ −
* writing in any buffers.+ −
*/+ −
#if defined(PNG_WRITE_FLUSH_SUPPORTED)+ −
void /* PRIVATE */+ −
png_flush(png_structp png_ptr)+ −
{+ −
if (png_ptr->output_flush_fn != NULL)+ −
(*(png_ptr->output_flush_fn))(png_ptr);+ −
}+ −
+ − #if !defined(PNG_NO_STDIO)+ −
void PNGAPI+ −
png_default_flush(png_structp png_ptr)+ −
{+ −
#if !defined(_WIN32_WCE)+ −
png_FILE_p io_ptr;+ −
#endif+ −
if (png_ptr == NULL)+ −
return;+ −
#if !defined(_WIN32_WCE)+ −
io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));+ −
fflush(io_ptr);+ −
#endif+ −
}+ −
#endif+ −
#endif+ −
+ − /* This function allows the application to supply new output functions for+ −
* libpng if standard C streams aren't being used.+ −
*+ −
* This function takes as its arguments:+ −
* png_ptr - pointer to a png output data structure+ −
* io_ptr - pointer to user supplied structure containing info about+ −
* the output functions. May be NULL.+ −
* write_data_fn - pointer to a new output function that takes as its+ −
* arguments a pointer to a png_struct, a pointer to+ −
* data to be written, and a 32-bit unsigned int that is+ −
* the number of bytes to be written. The new write+ −
* function should call png_error(png_ptr, "Error msg")+ −
* to exit and output any fatal error messages. May be+ −
* NULL, in which case libpng's default function will+ −
* be used.+ −
* flush_data_fn - pointer to a new flush function that takes as its+ −
* arguments a pointer to a png_struct. After a call to+ −
* the flush function, there should be no data in any buffers+ −
* or pending transmission. If the output method doesn't do+ −
* any buffering of ouput, a function prototype must still be+ −
* supplied although it doesn't have to do anything. If+ −
* PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile+ −
* time, output_flush_fn will be ignored, although it must be+ −
* supplied for compatibility. May be NULL, in which case+ −
* libpng's default function will be used, if+ −
* PNG_WRITE_FLUSH_SUPPORTED is defined. This is not+ −
* a good idea if io_ptr does not point to a standard+ −
* *FILE structure.+ −
*/+ −
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)+ −
{+ −
if (png_ptr == NULL)+ −
return;+ −
+ − png_ptr->io_ptr = io_ptr;+ −
+ − #if !defined(PNG_NO_STDIO)+ −
if (write_data_fn != NULL)+ −
png_ptr->write_data_fn = write_data_fn;+ −
+ − else+ −
png_ptr->write_data_fn = png_default_write_data;+ −
#else+ −
png_ptr->write_data_fn = write_data_fn;+ −
#endif+ −
+ − #if defined(PNG_WRITE_FLUSH_SUPPORTED)+ −
#if !defined(PNG_NO_STDIO)+ −
if (output_flush_fn != NULL)+ −
png_ptr->output_flush_fn = output_flush_fn;+ −
+ − else+ −
png_ptr->output_flush_fn = png_default_flush;+ −
#else+ −
png_ptr->output_flush_fn = output_flush_fn;+ −
#endif+ −
#endif /* PNG_WRITE_FLUSH_SUPPORTED */+ −
+ − /* It is an error to read while writing a png file */+ −
if (png_ptr->read_data_fn != NULL)+ −
{+ −
png_ptr->read_data_fn = NULL;+ −
png_warning(png_ptr,+ −
"Attempted to set both read_data_fn and write_data_fn in");+ −
png_warning(png_ptr,+ −
"the same structure. Resetting read_data_fn to NULL.");+ −
}+ −
}+ −
+ − #if defined(USE_FAR_KEYWORD)+ −
#if defined(_MSC_VER)+ −
void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)+ −
{+ −
void *near_ptr;+ −
void FAR *far_ptr;+ −
FP_OFF(near_ptr) = FP_OFF(ptr);+ −
far_ptr = (void FAR *)near_ptr;+ −
+ − if (check != 0)+ −
if (FP_SEG(ptr) != FP_SEG(far_ptr))+ −
png_error(png_ptr, "segment lost in conversion");+ −
+ − return(near_ptr);+ −
}+ −
# else+ −
void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)+ −
{+ −
void *near_ptr;+ −
void FAR *far_ptr;+ −
near_ptr = (void FAR *)ptr;+ −
far_ptr = (void FAR *)near_ptr;+ −
+ − if (check != 0)+ −
if (far_ptr != ptr)+ −
png_error(png_ptr, "segment lost in conversion");+ −
+ − return(near_ptr);+ −
}+ −
# endif+ −
# endif+ −
#endif /* PNG_WRITE_SUPPORTED */+ −