Difficult File Compare

[FantastichenEin]

Ok,
I have two files (4mb each).
These are data files and contain data as follows:

A header
10 - 12 Lines of data under the header

This is repated through the file,
I need to create a process to check the data (1 header and its data below) from one file with the same data from another.
If the data is different (e.g Has a new line below header)

Trouble is the data (Headers) are in different places throughout the file compared to the other file.

Sorry if not explained well
Any help appreciated greatly

[Kersey]

are you already able to open both files ?

are the headers unique ?

[FantastichenEin]

Yup, Can open both files.
It needs to be memory efficient so I can load the files into arrays.
Here is sample data.

0101,FR000000016447O0006       025,"CARREFOUR P3M PERP TSR B      ", 25, 203,    5000.00,"FRF",     762.24509,"EUR","EUR",     762.24509,"EUR",19890727,        ,20081215,"              ",    0.000,  12.00, 2, 15,   0.25,   1.00,    0.000,    0.000,20090727, 2,512, 1,     15.245,20090727,     762.24509, 1,   1.00,"FR0000164477", 3,19890727,  5.246801, 6,020800,"CARREFOUR                     ",
0301,FR000000016447O0006       025,20000825,  0.401000,
1001,FR000000016447O0006       025, 12,20010727,     39.99348,     39.99348,       0.00000,          20000, 100.0000,   0.0000,
1001,FR000000016447O0006       025, 13,20020727,     40.25416,     40.25416,       0.00000,          20000, 100.0000,   0.0000,
1001,FR000000016447O0006       025, 14,20030727,     40.25416,     40.25416,       0.00000,          20000, 100.0000,   0.0000,
1001,FR000000016447O0006       025, 15,20040727,     40.25416,     40.25416,       0.00000,          20000, 100.0000,   0.0000,
1001,FR000000016447O0006       025, 16,20050727,     49.78223,     49.78223,       0.00000,          20000, 100.0000,   0.0000,
1001,FR000000016447O0006       025, 17,20060727,     49.78223,     49.78223,       0.00000,          20000, 100.0000,   0.0000,
1001,FR000000016447O0006       025, 18,20070727,     49.78223,     49.78223,       0.00000,          20000, 100.0000,   0.0000,
1001,FR000000016447O0006       025, 19,20080727,     49.78223,     49.78223,       0.00000,          20000, 100.0000,   0.0000,
1001,FR000000016447O0006       025, 20,20090727,     53.59345,     53.59345,     762.24509,          20000, 100.0000, 100.0000,
0101,FR000000016448O0000       025,"CARREFOUR P3M PERP TSR C      ", 25, 203,    5000.00,"FRF",     762.24509,"EUR","EUR",     762.24509,"EUR",19890727,        ,        ,"              ",    0.000,  12.00, 1, 15,   0.30,   1.00,    0.000,    0.000,20390727, 2,545, 1,     15.245,        ,       0.00000, 0,   0.00,"FR0000164485", 0,19890727,  5.296800, 6,020800,"CARREFOUR                     ",
0301,FR000000016448O0000       025,20000825,  0.405000,
1001,FR000000016448O0000       025, 12,20010727,     40.37460,     40.37460,       0.00000,          20000, 100.0000,   0.0000,
1001,FR000000016448O0000       025, 13,2002072...........

This data is recieved every day and the recived file will be compare with the previous days file. If there are any changes to the data then these records are written to a new file.


Ok
0101 Is the Header (never changes) however the position of the headers (line number) is often different. If any of the 1001 data if different the whole record mus be written to the new file.

If you need anymore info just ask

[kedaman]

Ok i know nothing about your file format, so i could start with asking you how the header looks like, i think it decides the data size? And all headers must be the same size. The size should be specified in bytes, not lines

Then you can open the file in binary and read the headers as UDT's and then the next data section into a variable length string for instance. Then you compare the strings with = if you want binary comparation or you can use like operator for noncasesensitive comparation... of course you don't have to do this at all if the size specified in the header are different. Then you just loop trough the whole file (btw do you have an overall header to the whole file in which yo specify the amount of records?

[FantastichenEin]

Just a quick thanks,
I managed to solve the problem
Cheers