[Tutor] Tutor Digest, Vol 106, Issue 42

[Peter Otten]

Marefe Serentas wrote:

> On 12/18/2012 12:38 AM, tutor-request at python.org wrote:
>> Re: Get the structure values from a c file
> I apologize for some syntax errors in my c file. I would like to correct
> my mistakes and append some lines in the c file to make it clearer.
> 
> 
> ----
> #define max (3)
> #define max_data_size (9600*2*8)
> 
> typedef unsigned char  u8;
> typedef signed int u32;
> 
> int some_data[] =
> {
> -288,   -153,     31,     24,    205,    110,     39,     88,
> -281,    145,     35,    266,     63,    -79,   -103,    -25,
> 53,    145,   -114,   -274,     46,     60,    220,    205
> };
> 
> typedef struct A
> {
>      u32 a;
>      u8 b;
> }A;
> 
> typedef struct MainStruct
> {
>      A var1;
>      u32 var2;
>      u32 var3[max];
>      u32 var4;
>      u32 var5[max];
> }MainStruct;
> 
> void generate()
> {
>      MainStruct myMain = {0};
>      myMain.var1.a = 1;
>      myMain.var1.b = 'a';
>      myMain.var2 = 3;
>      myMain.var3[0] = -3;
>      myMain.var3[1] = 6;
>      myMain.var3[2] = 18;
> 
>      (void)memcpy((void *)myMain.var4,
>                   (void *)some_data,
>                   sizeof(some_data));
> 
>      myMain.var5[0] = 1;
> }
> 
> ----
> 
> 
> This is a work-problem. Given a c file as input, the customer wants me
> to write a python script that will retrieve the values of myMain.
> He wants those values converted to binary data and write it in a .bin
> file. As a result, the size of the bin file is equal to the size of
> myMain. The c file input content might change in the future like
> different values assigned, added fields in the MainStruct, etc. Also I
> am not permitted to change the c file.
> 
> 
> About me, I'm a fresh graduate. I just started learning python a month
> ago. I learned c in school, we had it for 2 years.
> 
> 
> I'm using python 2.6. I'm running on Windows 7 64-bit OS.
> 
> What I did so far is parse the C source code.
> But having a problem parsing the value of myMain.var4.

How about running the C source with an added dump() function

dump(MainStruct *s, char *filename)
{
  FILE * f = fopen(filename, "wb");
  fwrite(f, sizeof(MainStruct), 1, f);
  fclose(f);
}

in the right places?