Re: making data files with gcc

[Brian Budge <brian dot budge at gmail dot com>]

I think you left out the code that actually writes these structs to
file... that might help us identify the problem.

  Brian

On 12/26/05, Dale Walsh <websrvr@daleenterprise.com> wrote:
> I'm trying to generate data files however it seems to be prepending
> 244 bytes of data and I can't see how to prevent this.
>
> The actual data files are very large and manually using a hex editor
> to generate them isn't appealing considering there are about 300 of
> them.
>
>
>
> Here is my test compile session with a reduced file with 2 rows of 10
> bytes so the file should be 32 bytes in length.
>
> test.c: (combined header and source)
> ___________________________
>
>    typedef struct
>    {
>      /* # of entries in data */
>      int entries;
>      /* entry size and count */
>      int size;
>      int cnt;
>      /* data; array of bytes, one row after another. */
>      char *data;
>    }
>    gFast;
>
> /* Location functions take these. */
>    typedef gFast * gFastPtr;
>
> char TestDATA[20];
>
> gFast gFastTestRep = {
>         2,
>         2,
>         10,
>         TestDATA
> };
>
> gFastPtr gFastTest = &gFastTestRep;
> /*
>     this is all the data
>     the file should be 32 bytes in length
>    20 bytes of data and 12 bytes for header
> */
>
> char TestDATA[] = {
>
>         /* Entry 000 */
>         1,2,3,4,5,6,7,8,9,10,
>
>         /* Entry 001 */
>         11,12,13,14,15,16,17,18,19,20,
> };
>
> ___________________________
>
>
> compiled with:
> gcc -pipe -static -c -o test.out test.c
>
> ___________________________
>
>
> Here's the resulting file content, there are always 244 leading bytes
> of data that I can't have, the stuff appended to the end would also
> be nice to not have however it wont interfere with the file being
> valid to the application and isn't as critical.
>
> mustangrestomods:/temp2/clamav-0.80 root# hexdump -vC test.out
> 00000000  fe ed fa ce 00 00 00 12  00 00 00 00 00 00 00 01
> |................|
> 00000010  00 00 00 02 00 00 00 d8  00 00 20 00 00 00 00 01
> |.......... .....|
> 00000020  00 00 00 c0 00 00 00 00  00 00 00 00 00 00 00 00
> |................|
> 00000030  00 00 00 00 00 00 00 00  00 00 00 28 00 00 00 f4
> |...........(....|
> 00000040  00 00 00 28 00 00 00 07  00 00 00 07 00 00 00 02  |...
> (............|
> 00000050  00 00 00 00 5f 5f 74 65  78 74 00 00 00 00 00 00
> |....__text......|
> 00000060  00 00 00 00 5f 5f 54 45  58 54 00 00 00 00 00 00
> |....__TEXT......|
> 00000070  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 f4
> |................|
> 00000080  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
> |................|
> 00000090  00 00 00 00 00 00 00 00  5f 5f 64 61 74 61 00 00
> |........__data..|
> 000000a0  00 00 00 00 00 00 00 00  5f 5f 44 41 54 41 00 00
> |........__DATA..|
> 000000b0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 28
> |...............(|
> 000000c0  00 00 00 f4 00 00 00 02  00 00 01 1c 00 00 00 02
> |................|
> 000000d0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 02
> |................|
> 000000e0  00 00 00 18 00 00 01 2c  00 00 00 03 00 00 01 50
> |.......,.......P|
> 000000f0  00 00 00 24 00 00 00 02  00 00 00 02 00 00 00 0a  |...
> $............|
> 00000100  00 00 00 14 00 00 00 00  01 02 03 04 05 06 07 08
> |................|
> 00000110  09 0a 0b 0c 0d 0e 0f 10  11 12 13 14 00 00 00 10
> |................|
> 00000120  00 00 02 40 00 00 00 0c  00 00 02 40 00 00 00 0f
> |...@.......@....|
> 00000130  0f 02 00 00 00 00 00 14  00 00 00 19 0f 02 00 00
> |................|
> 00000140  00 00 00 10 00 00 00 01  0f 02 00 00 00 00 00 00
> |................|
> 00000150  00 5f 67 46 61 73 74 54  65 73 74 52 65 70 00 5f
> |._gFastTestRep._|
> 00000160  54 65 73 74 44 41 54 41  00 5f 67 46 61 73 74 54  |
> TestDATA._gFastT|
> 00000170  65 73 74 00                                       |est.|
> 00000174
>
>
>
>
> -- Dale
>
>