serialization of an dynamic array to read/write a image in xml

Hello
I like to store and load images from a xml file.
My problem is now the dynamic array which keeps the image data. I do
not want to copy it into a container and I do not want to go in a for
loop over every pixel.
Any suggestions?
Thanks
Max
#include <fstream>
#include

Am Tuesday 22 September 2009 15:23:39 schrieb Markus Bader:
Hello
I like to store and load images from a xml file. My problem is now the dynamic array which keeps the image data. I do not want to copy it into a container and I do not want to go in a for loop over every pixel. Any suggestions?
archives must implement load_binary/save_binary functions you can use. you have to split your serialize function into load/save functions and can call load_binary/save_binary from there. see http://www.boost.org/doc/libs/1_40_0/libs/serialization/doc/archives.html#sa... I guess a XML archives translate the binary data to encoded text, but that's just a wild guess, I've never tried it.

Stefan Strasser wrote:
I guess a XML archives translate the binary data to encoded text, but that's just a wild guess, I've never tried it.
I've done it...and stopped doing it shortly thereafter due to how slow the deserialization process was compared to non-text formats.

Markus Bader wrote:
Hello
I like to store and load images from a xml file. My problem is now the dynamic array which keeps the image data. I do not want to copy it into a container and I do not want to go in a for loop over every pixel. Any suggestions? ar & make_nvp("data", make_array(mpData, mWidth*mHeight)) ?

Damien R wrote:
Markus Bader wrote:
Hello
I like to store and load images from a xml file. My problem is now the dynamic array which keeps the image data. I do not want to copy it into a container and I do not want to go in a for loop over every pixel. Any suggestions? ar & make_nvp("data", make_array(mpData, mWidth*mHeight)) ?
also you could try ar & make_nvp("data", binary_object(sizeof(mpData), & mpData)) the cost of xml archiving is going to dominate even if you were to use the default serialization method whch loops over every pixel. XML just has a lot of extra characters and requires parsing - it has to be much slower then a binary format. Robert Ramey

Robert Ramey wrote:
also you could try
ar & make_nvp("data", binary_object(sizeof(mpData), & mpData)) This code do not work for dynamic allocation of mpData. data_type * mpData = new data_type[MAX]; sizeof(mpData) = sizeof(data_type *);
but it will be fine if you have static allocation : data_type mpData[MAX]; sizeof(mpData) = MAX * sizeof(data_type);

Thanks all of you for your ideas and suggestions
I finally realized the serialize(archive& ar, const unsigned) funktion using
ar & make_nvp("data", make_binary_object(mpData, mWidth*mHeight);
but I have to say that the memory behind mpData bust be allocated
first on reading an image.
Finaly I endet up with
template<class archive>
void serialize(archive& ar, const unsigned int version) {
using boost::serialization::make_nvp;
using boost::serialization::make_binary_object;
if (archive::is_saving::value) {
ar & make_nvp("width", mWidth);
ar & make_nvp("height", mHeight);
ar & make_nvp("data", make_binary_object(mpData, mWidth*mHeight);
} else if (archive::is_loading::value)
int w, h;{
ar & make_nvp("width", w);
ar & make_nvp("height", h);
2009/9/25 Damien R
Robert Ramey wrote:
also you could try
ar & make_nvp("data", binary_object(sizeof(mpData), & mpData))
This code do not work for dynamic allocation of mpData. data_type * mpData = new data_type[MAX]; sizeof(mpData) = sizeof(data_type *);
but it will be fine if you have static allocation : data_type mpData[MAX]; sizeof(mpData) = MAX * sizeof(data_type);
_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
-- Dipl.-Ing. Markus Bader ACIN | AUTOMATION & CONTROL INSTITUTE INSTITUT FÜR AUTOMATISIERUNGS- & REGELUNGSTECHNIK TECHNISCHE UNIVERSITÄT WIEN Gußhausstraße 27-29 | 376. 1040 Wien DVR-Nummer: 0005886 Tel. +43 (0)1 58801 - 37664 Skype: markus.bader.at.work Fax. +43 (0)1 58801 - 37697 bader@acin.tuwien.ac.at | www.acin.tuwien.ac.at

Solved
Thanks all of you for your ideas and suggestions
I finally realized the serialize(archive& ar, const unsigned) funktion using
ar & make_nvp("data", make_binary_object(mpData, mWidth*mHeight);
but I have to say that the memory behind mpData bust be allocated
first on reading an image.
Finaly I endet up with
template<class archive>
void serialize(archive& ar, const unsigned int version) {
using boost::serialization::make_nvp;
using boost::serialization::make_binary_object;
if (archive::is_saving::value) {
ar & make_nvp("width", mWidth);
ar & make_nvp("height", mHeight);
} else if (archive::is_loading::value)
int w, h;{
ar & make_nvp("width", w);
ar & make_nvp("height", h);
if ((w != mWidth) || (h != mHeight) {
w = mWidth; h = mHeight;
if(mpData != NULL) delete mpData;
mpData = new char[w*h];
}
ar & make_nvp("data", make_binary_object(mpData, mWidth*mHeight);
}
Thanks again
Markus
2009/9/25 Damien R
Robert Ramey wrote:
also you could try
ar & make_nvp("data", binary_object(sizeof(mpData), & mpData))
This code do not work for dynamic allocation of mpData. data_type * mpData = new data_type[MAX]; sizeof(mpData) = sizeof(data_type *);
but it will be fine if you have static allocation : data_type mpData[MAX]; sizeof(mpData) = MAX * sizeof(data_type);
_______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
-- Dipl.-Ing. Markus Bader ACIN | AUTOMATION & CONTROL INSTITUTE INSTITUT FÜR AUTOMATISIERUNGS- & REGELUNGSTECHNIK TECHNISCHE UNIVERSITÄT WIEN Gußhausstraße 27-29 | 376. 1040 Wien DVR-Nummer: 0005886 Tel. +43 (0)1 58801 - 37664 Skype: markus.bader.at.work Fax. +43 (0)1 58801 - 37697 bader@acin.tuwien.ac.at | www.acin.tuwien.ac.at
participants (5)
-
Damien R
-
Kenny Riddile
-
Markus Bader
-
Robert Ramey
-
Stefan Strasser