pngfuncs.cpp

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// $Id: pngfuncs.cpp 1282 2006-06-09 09:46:49Z alex $
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 */
// Replacements for some libpng functions (pointers to these functions
// are passed to libpng)

#include "camtypes.h"
#include "png.h"
#include "pngprgrs.h"
#include "pngutil.h"
//#include "fixmem.h" - in camtypes.h [AUTOMATICALLY REMOVED]

/******************************************************************* 

>       void camelot_png_error(png_structp png_ptr,
                                        png_const_charp message)

        Author:     Jonathan_Payne (Xara Group Ltd) <camelotdev@xara.com>
        Created:    29/8/2000
        Inputs:     png_ptr, error message
        Outputs:    Error message
        Returns:    void
        Purpose:    Pointer to this function given to libpng to be
                    called in case of error.
*******************************************************************/

void camelot_png_error(png_structp png_ptr, png_const_charp message)
{
    TRACEUSER( "Gavin", _T("PNG: libpng error: %s\n"), message);
    
    // Use the error handler in the PNG util function which assumes TRY CATCH block in
    // operation and CCFile present, in which case it will use the CCFile GotError function
    //  PNGUtil::DefaultErrorHandler(MessageID, message);
    PNGUtil::DefaultErrorHandler();
}

/******************************************************************* 

>       void camelot_png_warning(png_structp png_ptr,
                                png_const_charp message)

        Author:     Jonathan_Payne (Xara Group Ltd) <camelotdev@xara.com>
        Created:    29/8/2000
        Inputs:     png_ptr, warning message
        Outputs:    Nothing (except a trace message)
        Returns:    void
        Purpose:    Pointer to this function given to libpng to be
                    called in case of warning.
*******************************************************************/

void camelot_png_warning(png_structp png_ptr, png_const_charp message)
{
    if (!png_ptr)
        return;
    
    TRACEUSER( "Gavin", _T("PNG: libpng warning: %s\n"), message);
}

/******************************************************************* 

>       void camelot_png_read_data(png_structp png_ptr, 
                                png_bytep data, png_size_t length)

        Author:     Jonathan_Payne (Xara Group Ltd) <camelotdev@xara.com>
        Created:    29/8/2000
        Inputs:     png_ptr, amount to be read
        Outputs:    'data' set to data from file
        Returns:    void
        Purpose:    Pointer to this function given to libpng to be
                    called for reading data.
*******************************************************************/

void camelot_png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
    iostream *fp = (iostream *)png_get_io_ptr(png_ptr);
    png_uint_32 check = png_uint_32(length);
    
    if (fp)
        fp->read((char *) data, check );
    else
        png_error(png_ptr, "Read Error");
    
    if (check != length)
    {
        png_error(png_ptr, "Read Error");
    }
}

/******************************************************************* 

>       void camelot_png_write_data(png_structp png_ptr, 
                                png_bytep data, png_size_t length)

        Author:     Jonathan_Payne (Xara Group Ltd) <camelotdev@xara.com>
        Created:    29/8/2000
        Inputs:     png_ptr, amount to be written, data
        Outputs:    Data in file
        Returns:    void
        Purpose:    Pointer to this function given to libpng to be
                    called for writting data.
*******************************************************************/

void camelot_png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
{
    iostream *fp = (iostream *)png_get_io_ptr(png_ptr);
    png_uint_32 check = png_uint_32(length);

    if (fp)
        fp->write((const char*)data, check);
    else
        png_error(png_ptr, "Write Error");

    if (check != length)
    {
        png_error(png_ptr, "Write Error");
    }
}

/******************************************************************* 

>       void camelot_png_flush_data(png_structp png_ptr)

        Author:     Jonathan_Payne (Xara Group Ltd) <camelotdev@xara.com>
        Created:    29/8/2000
        Inputs:     png_ptr
        Outputs:    Output stream flushed
        Returns:    void
        Purpose:    Pointer to this function given to libpng to be
                    called for flushing output stream on write.
*******************************************************************/

void camelot_png_flush_data(png_structp png_ptr)
{
    iostream *fp = (iostream *)png_get_io_ptr(png_ptr);

    if (fp)
        fp->flush();
}

/******************************************************************* 

>       void camelot_png_malloc(png_structp png_ptr, png_size_t size)

        Author:     Jonathan_Payne (Xara Group Ltd) <camelotdev@xara.com>
        Created:    29/8/2000
        Inputs:     png_ptr, size of memory
        Outputs:    Memory block
        Returns:    void * to memory
        Purpose:    Pointer to this function given to libpng to be
                    called for allocing memory.
*******************************************************************/

void *camelot_png_malloc(png_structp png_ptr, png_size_t size)
{
    return (CCMalloc(size));
}

/******************************************************************* 

>       void camelot_png_free(png_structp png_ptr, png_voidp data)

        Author:     Jonathan_Payne (Xara Group Ltd) <camelotdev@xara.com>
        Created:    29/8/2000
        Inputs:     png_ptr, &data
        Returns:    void
        Purpose:    Pointer to this function given to libpng to be
                    called for freeing data.
*******************************************************************/

void camelot_png_free(png_structp png_ptr, png_voidp data)
{
    CCFree(data);
}

/******************************************************************* 

>       void camelot_png_write_row_callback
            (png_structp png_ptr, png_uint_32 row_number, INT32 pass)

        Author:     Jonathan_Payne (Xara Group Ltd) <camelotdev@xara.com>
        Created:    29/8/2000
        Inputs:     png_ptr, row, pass
        Outputs:    Status bar update
        Returns:    void
        Purpose:    Pointer to this function given to libpng to be
                    called when a row has been read.

                    IMPORTANT NOTE: This function is not used, I have
                    just included it for completness (the write code does
                    its own status bar updates).
*******************************************************************/

void camelot_png_write_row_callback
            (png_structp png_ptr, png_uint_32 row_number, INT32 pass)
{
}

---