nuclear@26: 
nuclear@26: /* pngwio.c - functions for data output
nuclear@26:  *
nuclear@26:  * Last changed in libpng 1.2.30 [August 15, 2008]
nuclear@26:  * For conditions of distribution and use, see copyright notice in png.h
nuclear@26:  * Copyright (c) 1998-2008 Glenn Randers-Pehrson
nuclear@26:  * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
nuclear@26:  * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
nuclear@26:  *
nuclear@26:  * This file provides a location for all output.  Users who need
nuclear@26:  * special handling are expected to write functions that have the same
nuclear@26:  * arguments as these and perform similar functions, but that possibly
nuclear@26:  * use different output methods.  Note that you shouldn't change these
nuclear@26:  * functions, but rather write replacement functions and then change
nuclear@26:  * them at run time with png_set_write_fn(...).
nuclear@26:  */
nuclear@26: 
nuclear@26: #define PNG_INTERNAL
nuclear@26: #include "png.h"
nuclear@26: #ifdef PNG_WRITE_SUPPORTED
nuclear@26: 
nuclear@26: /* Write the data to whatever output you are using.  The default routine
nuclear@26:    writes to a file pointer.  Note that this routine sometimes gets called
nuclear@26:    with very small lengths, so you should implement some kind of simple
nuclear@26:    buffering if you are using unbuffered writes.  This should never be asked
nuclear@26:    to write more than 64K on a 16 bit machine.  */
nuclear@26: 
nuclear@26: void /* PRIVATE */
nuclear@26: png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
nuclear@26: {
nuclear@26:    if (png_ptr->write_data_fn != NULL )
nuclear@26:       (*(png_ptr->write_data_fn))(png_ptr, data, length);
nuclear@26:    else
nuclear@26:       png_error(png_ptr, "Call to NULL write function");
nuclear@26: }
nuclear@26: 
nuclear@26: #if !defined(PNG_NO_STDIO)
nuclear@26: /* This is the function that does the actual writing of data.  If you are
nuclear@26:    not writing to a standard C stream, you should create a replacement
nuclear@26:    write_data function and use it at run time with png_set_write_fn(), rather
nuclear@26:    than changing the library. */
nuclear@26: #ifndef USE_FAR_KEYWORD
nuclear@26: void PNGAPI
nuclear@26: png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
nuclear@26: {
nuclear@26:    png_uint_32 check;
nuclear@26: 
nuclear@26:    if (png_ptr == NULL) return;
nuclear@26: #if defined(_WIN32_WCE)
nuclear@26:    if ( !WriteFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
nuclear@26:       check = 0;
nuclear@26: #else
nuclear@26:    check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
nuclear@26: #endif
nuclear@26:    if (check != length)
nuclear@26:       png_error(png_ptr, "Write Error");
nuclear@26: }
nuclear@26: #else
nuclear@26: /* this is the model-independent version. Since the standard I/O library
nuclear@26:    can't handle far buffers in the medium and small models, we have to copy
nuclear@26:    the data.
nuclear@26: */
nuclear@26: 
nuclear@26: #define NEAR_BUF_SIZE 1024
nuclear@26: #define MIN(a,b) (a <= b ? a : b)
nuclear@26: 
nuclear@26: void PNGAPI
nuclear@26: png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
nuclear@26: {
nuclear@26:    png_uint_32 check;
nuclear@26:    png_byte *near_data;  /* Needs to be "png_byte *" instead of "png_bytep" */
nuclear@26:    png_FILE_p io_ptr;
nuclear@26: 
nuclear@26:    if (png_ptr == NULL) return;
nuclear@26:    /* Check if data really is near. If so, use usual code. */
nuclear@26:    near_data = (png_byte *)CVT_PTR_NOCHECK(data);
nuclear@26:    io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
nuclear@26:    if ((png_bytep)near_data == data)
nuclear@26:    {
nuclear@26: #if defined(_WIN32_WCE)
nuclear@26:       if ( !WriteFile(io_ptr, near_data, length, &check, NULL) )
nuclear@26:          check = 0;
nuclear@26: #else
nuclear@26:       check = fwrite(near_data, 1, length, io_ptr);
nuclear@26: #endif
nuclear@26:    }
nuclear@26:    else
nuclear@26:    {
nuclear@26:       png_byte buf[NEAR_BUF_SIZE];
nuclear@26:       png_size_t written, remaining, err;
nuclear@26:       check = 0;
nuclear@26:       remaining = length;
nuclear@26:       do
nuclear@26:       {
nuclear@26:          written = MIN(NEAR_BUF_SIZE, remaining);
nuclear@26:          png_memcpy(buf, data, written); /* copy far buffer to near buffer */
nuclear@26: #if defined(_WIN32_WCE)
nuclear@26:          if ( !WriteFile(io_ptr, buf, written, &err, NULL) )
nuclear@26:             err = 0;
nuclear@26: #else
nuclear@26:          err = fwrite(buf, 1, written, io_ptr);
nuclear@26: #endif
nuclear@26:          if (err != written)
nuclear@26:             break;
nuclear@26:          else
nuclear@26:             check += err;
nuclear@26:          data += written;
nuclear@26:          remaining -= written;
nuclear@26:       }
nuclear@26:       while (remaining != 0);
nuclear@26:    }
nuclear@26:    if (check != length)
nuclear@26:       png_error(png_ptr, "Write Error");
nuclear@26: }
nuclear@26: 
nuclear@26: #endif
nuclear@26: #endif
nuclear@26: 
nuclear@26: /* This function is called to output any data pending writing (normally
nuclear@26:    to disk).  After png_flush is called, there should be no data pending
nuclear@26:    writing in any buffers. */
nuclear@26: #if defined(PNG_WRITE_FLUSH_SUPPORTED)
nuclear@26: void /* PRIVATE */
nuclear@26: png_flush(png_structp png_ptr)
nuclear@26: {
nuclear@26:    if (png_ptr->output_flush_fn != NULL)
nuclear@26:       (*(png_ptr->output_flush_fn))(png_ptr);
nuclear@26: }
nuclear@26: 
nuclear@26: #if !defined(PNG_NO_STDIO)
nuclear@26: void PNGAPI
nuclear@26: png_default_flush(png_structp png_ptr)
nuclear@26: {
nuclear@26: #if !defined(_WIN32_WCE)
nuclear@26:    png_FILE_p io_ptr;
nuclear@26: #endif
nuclear@26:    if (png_ptr == NULL) return;
nuclear@26: #if !defined(_WIN32_WCE)
nuclear@26:    io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));
nuclear@26:    if (io_ptr != NULL)
nuclear@26:       fflush(io_ptr);
nuclear@26: #endif
nuclear@26: }
nuclear@26: #endif
nuclear@26: #endif
nuclear@26: 
nuclear@26: /* This function allows the application to supply new output functions for
nuclear@26:    libpng if standard C streams aren't being used.
nuclear@26: 
nuclear@26:    This function takes as its arguments:
nuclear@26:    png_ptr       - pointer to a png output data structure
nuclear@26:    io_ptr        - pointer to user supplied structure containing info about
nuclear@26:                    the output functions.  May be NULL.
nuclear@26:    write_data_fn - pointer to a new output function that takes as its
nuclear@26:                    arguments a pointer to a png_struct, a pointer to
nuclear@26:                    data to be written, and a 32-bit unsigned int that is
nuclear@26:                    the number of bytes to be written.  The new write
nuclear@26:                    function should call png_error(png_ptr, "Error msg")
nuclear@26:                    to exit and output any fatal error messages.
nuclear@26:    flush_data_fn - pointer to a new flush function that takes as its
nuclear@26:                    arguments a pointer to a png_struct.  After a call to
nuclear@26:                    the flush function, there should be no data in any buffers
nuclear@26:                    or pending transmission.  If the output method doesn't do
nuclear@26:                    any buffering of ouput, a function prototype must still be
nuclear@26:                    supplied although it doesn't have to do anything.  If
nuclear@26:                    PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
nuclear@26:                    time, output_flush_fn will be ignored, although it must be
nuclear@26:                    supplied for compatibility. */
nuclear@26: void PNGAPI
nuclear@26: png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
nuclear@26:    png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
nuclear@26: {
nuclear@26:    if (png_ptr == NULL) return;
nuclear@26:    png_ptr->io_ptr = io_ptr;
nuclear@26: 
nuclear@26: #if !defined(PNG_NO_STDIO)
nuclear@26:    if (write_data_fn != NULL)
nuclear@26:       png_ptr->write_data_fn = write_data_fn;
nuclear@26:    else
nuclear@26:       png_ptr->write_data_fn = png_default_write_data;
nuclear@26: #else
nuclear@26:    png_ptr->write_data_fn = write_data_fn;
nuclear@26: #endif
nuclear@26: 
nuclear@26: #if defined(PNG_WRITE_FLUSH_SUPPORTED)
nuclear@26: #if !defined(PNG_NO_STDIO)
nuclear@26:    if (output_flush_fn != NULL)
nuclear@26:       png_ptr->output_flush_fn = output_flush_fn;
nuclear@26:    else
nuclear@26:       png_ptr->output_flush_fn = png_default_flush;
nuclear@26: #else
nuclear@26:    png_ptr->output_flush_fn = output_flush_fn;
nuclear@26: #endif
nuclear@26: #endif /* PNG_WRITE_FLUSH_SUPPORTED */
nuclear@26: 
nuclear@26:    /* It is an error to read while writing a png file */
nuclear@26:    if (png_ptr->read_data_fn != NULL)
nuclear@26:    {
nuclear@26:       png_ptr->read_data_fn = NULL;
nuclear@26:       png_warning(png_ptr,
nuclear@26:          "Attempted to set both read_data_fn and write_data_fn in");
nuclear@26:       png_warning(png_ptr,
nuclear@26:          "the same structure.  Resetting read_data_fn to NULL.");
nuclear@26:    }
nuclear@26: }
nuclear@26: 
nuclear@26: #if defined(USE_FAR_KEYWORD)
nuclear@26: #if defined(_MSC_VER)
nuclear@26: void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)
nuclear@26: {
nuclear@26:    void *near_ptr;
nuclear@26:    void FAR *far_ptr;
nuclear@26:    FP_OFF(near_ptr) = FP_OFF(ptr);
nuclear@26:    far_ptr = (void FAR *)near_ptr;
nuclear@26:    if (check != 0)
nuclear@26:       if (FP_SEG(ptr) != FP_SEG(far_ptr))
nuclear@26:          png_error(png_ptr, "segment lost in conversion");
nuclear@26:    return(near_ptr);
nuclear@26: }
nuclear@26: #  else
nuclear@26: void *png_far_to_near(png_structp png_ptr, png_voidp ptr, int check)
nuclear@26: {
nuclear@26:    void *near_ptr;
nuclear@26:    void FAR *far_ptr;
nuclear@26:    near_ptr = (void FAR *)ptr;
nuclear@26:    far_ptr = (void FAR *)near_ptr;
nuclear@26:    if (check != 0)
nuclear@26:       if (far_ptr != ptr)
nuclear@26:          png_error(png_ptr, "segment lost in conversion");
nuclear@26:    return(near_ptr);
nuclear@26: }
nuclear@26: #   endif
nuclear@26: #   endif
nuclear@26: #endif /* PNG_WRITE_SUPPORTED */