Type conversion - string of characters to integer - type-conversion

Question

Hello I am writing my program in C, using PSoC tools to program my Cypress development kit. I am facing an issue regarding type conversion of a string of characters collected in my circular buffer (buffer) to a local variable "input_R", ultimately to a global variable st_input_R. The event in my FSM calling this action function is given below:
void st_state_5_event_0(void) //S6 OR S4
{
char buffer[ST_NODE_LIMIT] = {0};
st_copy_buffer(buffer);
uint32 input_R = {0};
mi_utoa(input_R, buffer);
if ((input_R >= 19000) && (input_R <= 26000))
{
st_input_R = input_R;
_st_data.state = ST_STATE_6;
}
else
{
_st_data.status = ST_STATE_4;
}
UART_1_Stop();
st_stop();
st_empty_buffer();
}
ST_NODE_LIMIT = 64
st_copy_buffer copies the the numbers I type in using hyper terminal to the circular buffer named "buffer".
input_R is the 32 bit integer I want the buffer content to be converted to.
mi_utoa is the function I am using for converting the contents in the buffer to input_R and is detailed below:
uint8 mi_utoa(uint32 number, char *string)
{
uint8 result = MI_BAD_ARGUMENT;
if (string != NULL)
{
uint8 c = 0;
uint8 i = 0;
uint8 j = 0;
do
{
string[i++] = number % 10 + '0';
} while ((number /=10) > 0);
string[i] = '\0';
for (i = 0, j = strlen(string) - 1 ; i < j ; i++, j--)
{
c = string[i];
string[i] = string[j];
string[j] = c;
}
result = MI_SUCCESS;
}
return result;
}
The problem is, suppose if I enter 21500(+\r), the mi_utoa function converts the first digit to 0 the second digit to \000 while the other digits including the carriage return "\r" remains unaltered. As a result the input_R is NOT = 21500. Its happening for any string of digits I input. So the condition "if ((input_R >= 19000) && (input_R <= 26000))" is never satisfied. Hence the FSM returns to state 4 all the time and I am going in circles.
Can you please advice where the bug is in the mi_utoa function? Let me know if you want to know any other details.

Answer 1

Your function st_state_5_event_0() sets the value input_R to zero. Then you call mi_utoa(), which converts the value input_R to an ascii string, "0".
void st_state_5_event_0(void) //S6 OR S4
{
char buffer[ST_NODE_LIMIT] = {0};
//what is the value of buffer after this statement?
st_copy_buffer(buffer);
//the value of input_R after the next statement is =0
uint32 input_R = {0};
//conversion of input_R to string will give ="0"
mi_utoa(input_R, buffer);
if ((input_R >= 19000) && (input_R <= 26000))
{
st_input_R = input_R;
_st_data.state = ST_STATE_6;
}
//...
}
You probably want a function which converts your ascii buffer to a number.
uint8
mi_atou(uint32* number, char *string)
{
uint8 result = MI_BAD_ARGUMENT;
if (!string) return result;
if (!number) return result;
uint8 ndx = 0;
uint32 accum=0;
for( ndx=0; string[ndx]; ++ndx )
{
if( (string[ndx] >= '0') && (string[ndx] <= '9') )
{
accum = accum*10 + (string[ndx]-'0');
//printf("[%d] %s -> %d\n",ndx,string,accum);
}
else break;
}
//printf("[%d] %s -> %d\n",ndx,string,accum);
*number = accum;
result = MI_SUCCESS;
return result;
}
Which you would call by providing the address of the number to store the result,
mi_atou(&input_R, buffer);