to dumb to read a string

to dumb to read a string

knudel

Member #13,235

August 2011

Hi,

my problem is that I've got a file in which I've written a string and two integers and I'm trying to read them with this function:

#SelectExpand
  1void read(char* path){
  2   file=al_fopen(path,"r");
  3
  4      char str[256];
  5      int mapx, mapy;
  6
  7      //string
  8      int i=-1;
  9      do{
 10         i++;
 11         al_fread(file,&str[i],sizeof(char));
 12      }while(str[i]!='\0');
 13
 14      //2 integers
 15      al_fread(file,&mapx,sizeof(int));
 16      al_fread(file,&mapy,sizeof(int));
 17
 18   al_fclose(file);
 19}

but it seems that my solution to read a string takes one byte more from the file as it should and so my string is "tiles1.bmpd" instead of "tiles1.bmp" and the following ints have the values 6553600 and 0 instead of 100 and 100.

Does anyone have a better solution for reading strings?

thanks for all answers

Arthur Kalliokoski

Second in Command

February 2005

Let me get this straight, the file has a null terminated string followed immediately by two binary integers? The ints aren't in ASCII?

They all watch too much MSNBC... they get ideas.

Trent Gamblin

Member #261

April 2000

I think I'm thinking along the same lines as Arthur. My guess is you didn't null terminate, or you had \n in the file before the 0.

knudel

Member #13,235

August 2011

Damn, I'm sorry.
I used al_fwrite(file,string,strlen(string)) and not al_fwrite(file,string,strlen(string)+1) to write the string in the file so the '\0'-charakter was missing.

Thanks for the hint

Trent Gamblin

Member #261

April 2000

Just so you know, read ints from a file 4 bytes at a time with fread isn't portable. Allegro has functions such as al_fread32le for this purpose.

knudel

Member #13,235

August 2011

thanks
So al_fread32le would work on all platforms correct?

Trent Gamblin

Member #261

April 2000

If you use that and write32le every time on all platforms then it will work.