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jaime
Joined: 25 Nov 2005
Posts: 56
Location: Porto - Portugal
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| Parsing a string from fat file |
 Posted: Tue Sep 08, 2009 2:52 pm |
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Hello
I'm using the ccs FAT drive to record readings from a GPS with no problem.
Now I would like to read from a file. I would like to read from config.txt the value of the interval between readings. I create a file named config.txt in the mmc card, and I write in the file #180# then the pic must read between ## the value and convert it to long int.
Any ideas to make it easy?
Thanks
jagsilva
Last edited by jaime on Wed Sep 09, 2009 6:46 pm; edited 1 time in total |
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jaime
Joined: 25 Nov 2005
Posts: 56
Location: Porto - Portugal
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| Posted: Wed Sep 09, 2009 5:23 pm |
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OK, I have this:
I read from the file one char and put in the valor[v] and I want to finish this do...while if I get one EOF or if v>5 or if char_in is a '*'.
It isnt working because it only get out of the do_while when i receive a EOF. The printf shows | Code: | | *123*testing testing |
What I want to do is to read the value inside the *xxx* and convert it to a int.
| Code: |
char char_in;
int v=0;
char valor[20];
do{
char_in = fatgetc(&stream); //fatgetc returns an sint
valor[v++] = char_in;
}while(char_in != EOF || v<5 || char_in != '*') ;
valor[v]="\0";
printf("%s", valor);
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Any ideas?
thanks |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Wed Sep 09, 2009 5:51 pm |
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I think your logic is wrong in your test. I think you want to stay in the
loop if all those things are true. You should change from the logical OR
operator to the logical AND operator (&&). However, there is still a bug
because it will drop out of the loop on the very first asterisk (*).
Also, you would have got more responses more quickly if you had put
the question in terms of parsing a stream, rather than an MMC/SD Card
FAT file system problem. There are only a very few people on here
who want to trouble-shoot such things, but a lot who will handle parsing
questions. |
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jaime
Joined: 25 Nov 2005
Posts: 56
Location: Porto - Portugal
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| Posted: Wed Sep 09, 2009 7:16 pm |
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thanks for your help.
I didn't see my error. Should be &&.
Well about the code. The idea is to have a logger and in the mmc I can create a txt file with some configurations.
I don't care about the length of file I just know that I must read the characters inside two **, convert it to a string and them to an int.
The solution that I found was the code above:
| Code: |
do{ //look for an *
char_in=fatgetc(&stream);
}while(char_in != EOF && char_in != '*');
if(char_in=='*') //found a * so keep the value till found next *
{
v=0;
do{ //record till EOF or next * and the value must be under 5 digit
valor[v++]=fatgetc(&stream);
}while(valor[v-1] != EOF && valor[v-1] != '*' && v<=5);
if(v>5 || valor[v-1]==EOF) //value too big or didnt find second *
contagem=1;
else //value found convert to int
{
valor[v-1]='\0';
contagem=atol(valor);
}
}
else // didnt found a * so contagem=1
contagem=1;
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What do you think about that?
thanks |
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