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Home » U++ Library support » U++ Core » strange behaviour of Vector serialization (unexpectable data serialized)
strange behaviour of Vector serialization [message #54092] Sun, 31 May 2020 14:19 Go to next message
michael79 is currently offline  michael79
Messages: 4
Registered: May 2020
Junior Member
Here is the serialization of struct data which contains Vector(byte):

#pragma pack(push, 1)
struct OttMessage
{
uint16 descriptor;
uint16 msgNum;
int32 sec;
int32 nsec;

Vector<byte> data;

void Serialize(Stream& s)
{
s % descriptor % msgNum % sec % nsec % data;
}
};
#pragma pack(pop)


DUMP of buffer show the next:
(int)buf[0] = 102
(int)buf[1] = 0
(int)buf[2] = 111
(int)buf[3] = 0
(int)buf[4] = 123
(int)buf[5] = 0
(int)buf[6] = 0
(int)buf[7] = 0
(int)buf[8] = 222
(int)buf[9] = 0
(int)buf[10] = 0
(int)buf[11] = 0
(int)buf[12] = 7
(int)buf[13] = 10
(int)buf[14] = 144
(int)buf[15] = 56
(int)buf[16] = 233
(int)buf[17] = 77

Data from Vector begins since buf[12], but the value 7 unexpectable, it was not added to Vector.

When I change Serialize() as the following, then all data correct:

void Serialize(Stream& s)
{
s % descriptor % msgNum % sec % nsec;

for(int i = 0; i < data.size(); i++)
{
s % data[i];
}
}

(int)buf[0] = 102
(int)buf[1] = 0
(int)buf[2] = 111
(int)buf[3] = 0
(int)buf[4] = 123
(int)buf[5] = 0
(int)buf[6] = 0
(int)buf[7] = 0
(int)buf[8] = 222
(int)buf[9] = 0
(int)buf[10] = 0
(int)buf[11] = 0
(int)buf[12] = 10
(int)buf[13] = 144
(int)buf[14] = 56
(int)buf[15] = 233
(int)buf[16] = 77
(int)buf[17] = 188

Can anyone explane such strange behaviour?
Why I need to add Vector data one by one?


Re: strange behaviour of Vector serialization [message #54097 is a reply to message #54092] Mon, 01 June 2020 00:19 Go to previous messageGo to next message
mirek is currently offline  mirek
Messages: 13995
Registered: November 2005
Ultimate Member
michael79 wrote on Sun, 31 May 2020 14:19
Here is the serialization of struct data which contains Vector(byte):

#pragma pack(push, 1)
struct OttMessage
{
uint16 descriptor;
uint16 msgNum;
int32 sec;
int32 nsec;

Vector<byte> data;

void Serialize(Stream& s)
{
s % descriptor % msgNum % sec % nsec % data;
}
};
#pragma pack(pop)


DUMP of buffer show the next:
(int)buf[0] = 102
(int)buf[1] = 0
(int)buf[2] = 111
(int)buf[3] = 0
(int)buf[4] = 123
(int)buf[5] = 0
(int)buf[6] = 0
(int)buf[7] = 0
(int)buf[8] = 222
(int)buf[9] = 0
(int)buf[10] = 0
(int)buf[11] = 0
(int)buf[12] = 7
(int)buf[13] = 10
(int)buf[14] = 144
(int)buf[15] = 56
(int)buf[16] = 233
(int)buf[17] = 77

Data from Vector begins since buf[12], but the value 7 unexpectable, it was not added to Vector.

When I change Serialize() as the following, then all data correct:

void Serialize(Stream& s)
{
s % descriptor % msgNum % sec % nsec;

for(int i = 0; i < data.size(); i++)
{
s % data[i];
}
}

(int)buf[0] = 102
(int)buf[1] = 0
(int)buf[2] = 111
(int)buf[3] = 0
(int)buf[4] = 123
(int)buf[5] = 0
(int)buf[6] = 0
(int)buf[7] = 0
(int)buf[8] = 222
(int)buf[9] = 0
(int)buf[10] = 0
(int)buf[11] = 0
(int)buf[12] = 10
(int)buf[13] = 144
(int)buf[14] = 56
(int)buf[15] = 233
(int)buf[16] = 77
(int)buf[17] = 188

Can anyone explane such strange behaviour?
Why I need to add Vector data one by one?




Well, it would not hurt if you posted more code. So I can only guess the buf is the result of Serialization (e.g. StoreAsString) etc...

In any case, the content of serialized code is the responsibility of class that does Serialize and there is no guarantee about what it contains.

In this case, it is definitely needed to store the number of elements. So I guess that is what that 7 is.

Mirek
Re: strange behaviour of Vector serialization [message #54100 is a reply to message #54097] Mon, 01 June 2020 01:03 Go to previous message
michael79 is currently offline  michael79
Messages: 4
Registered: May 2020
Junior Member
I also thought that 7 is the number of array elements. I just didn't know that this amount should also be serialized.

In fact, when the number of elements was 1, 2 appeared instead of 7.

7 appeared when there were 6 elements.

In General, I assumed that for Vector only array elements should be serialized and nothing else, so adding elements to the stream one at a time looks as a workaround, although adding elements within a loop is not a problem.

At the moment, I have not found information about how the Vector should be serialized.

Thanks for the answer.
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