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blo
Joined: 11 May 2009
Posts: 22
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| [rs-232] string to long int conversion |
 Posted: Fri Oct 09, 2009 7:57 am |
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Hi, I've got a pic connected to a PC via rs232. The pc send me a number (i.e. 2010) like 4 character (char 2, char 0, char 1, char 0), so the pc send me the ascii code for a single digit.
How can I translate this series of character into a unique long int representig the 2010 number?
thanks to anyone can help me. |
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Audi80
Joined: 07 Sep 2007
Posts: 41
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| Posted: Fri Oct 09, 2009 8:16 am |
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You could do something like this:
| Code: |
int32 convert(char * ptr){
int32 aux = 0;
char value[5] = "";
memset(value,0,sizeof(value));
value[0] = ptr[0];
value[1] = ptr[1];
value[2] = ptr[2];
value[3] = ptr[3];
printf("Received value: %lu \r\n",atoi32(value));
return atoi32(value);
}
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Hope it helps... |
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Wayne_
Joined: 10 Oct 2007
Posts: 681
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| Posted: Fri Oct 09, 2009 8:39 am |
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It all depends on some things.
What is the maximum value you will receive ?
Are the strings null terminated ?
Are any other characters sent with the number ?
If you receive the chars into an array and terminate it with a null char when you receieve the last one you can use
atoi(string) if it is max 8 bit value
atol(string) it is max a 16 bit value
atoi32(string) if it is max a 32 bit value.
If you are the one receving the chars you can do the math as you receieve each char
| Code: |
int32 val;
int c;
// get number routine
val = 0;
do
{
c = getc();
val = (val * 10) + (c - '0');
} while (c != 0);
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OK, so I just noticed you want a long int, it still depends on how you process the received chars. |
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Torello
Joined: 29 Sep 2006
Posts: 120
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| Posted: Thu Oct 15, 2009 11:48 am |
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Hi Blo,
I've written this function to do all that for an int16. Maybe you can expand to i32? Personally I dislike atoi32.
If you need examples how to use, I'l ppost them tomorrow. (need to go now)
Regards,
Edwin
| Code: |
//==============================================================================
//-UNSIGNED- decimal conversion
//Converts a string: variable length: ends with a non-decimal <=5 chars (len=0),
// or user specified length (len=1..5)
//returns error(=0) if:
// - len=0 and -no- seperator found after >5 digits (value too big)
// - value>65535
// - Len<>0 and length is not met (too few digits), -but- more is OK! (section conversion)
//if error -> result stays untouched
//if NO error -AND- len=0; function returns:
// - 1: conversion OK and string ended with '\0')
// - >1: conversion OK and string ended with a separator (so maybe more numbers to convert)
// returns length -including seperator-! (assuming one char!)
//if NO error -AND- len=x; function returns:
// - 1: conversion OK:
int8 StrToi16DecU(char *s, int8 len, int16 *result) {
char dig;
int8 i;
int16 sum=0;
if (len>5) len=5; // f*up proof
for(i=1; i<=6; i++) { //max loop for 6 chars (max 5 digits + end)
dig=s[i-1]; //get the char; correct for i starts at 1
if ( (dig<48) || (dig>57) ) { //T: non-decimal; end conversion
i--; //correct for length
break;
}
if (i==6) goto sti16d_err_exit; //..5 digits done, 6th is also a digit -> number too big.
dig -=48; //undo ASCII offset
if (i==5) { //T: 5th digit; start boumdary checking
if (sum>6553) goto sti16d_err_exit; //T: sum already too big for mult by 10
if ((sum==6553) && (dig>5)) goto sti16d_err_exit; //T: mult by w10 ould do, but last digit too big
}
sum = (sum*10) + dig;
if (len==i) break; //T: specified length match; stop calculation;
}
if (!i) goto sti16d_err_exit; //no single digit found (reason to start i at 1)
if ((i<len)) goto sti16d_err_exit; //specified len does not match
*result = sum;
if (!dig) return(1); //string ends '/0'
else {
if (!len) return(++i); //returns length including separator
return (1); //return Ok for specified len
}
sti16d_err_exit:
return(0);
}
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