Re: Converting packed decimal to a char array

On 17-Mar-2015 04:51 -0500, Jevgeni Astanovski wrote:

Big-big thanks to Barbara and Tim.

The result is:

void printdec(void *A, int Len, int Prec)
{
decimal(63,0) fulldec ;
int offset, bytes ;

bytes = (Len / 2) + 1;
offset = 32 - bytes;
fulldec = 0;
memcpy(((char *) &fulldec) + offset, A, bytes);
printf("%0*.*D(63,*)\n", (Len + 1), Prec, Prec, fulldec) ;
}

is exactly what I've been looking for.

The original requirements were not explicit, but if the alluded requirement for ensuring left-pad with zeroes implies *also* that a consistent length\layout of all valid values is required, then the formatting chosen for the above printf() might not be appropriate. That is because [excepting when Prec=0] both negative values and values of maximal digits will appear laid-out in storage differently than other values; i.e. all possible values would not align [with the decimal point in the same location] within a fixed-width column.

Some Example values for three variations of P(l,p) to exhibit the results with the aforementioned formatting:

P(09,2) P(03,0) P(06,6)
----------- ---- ---------
9876543.21 0321 0.660000
-9876543.21 -321 -0.660000
0876543.21 0001 0.000006
-876543.21 -001 -0.000006
0000000.21 0000 0.000000
-000000.21
0000000.00

The following formatting choices may be more appropriate, if alignment within a [report] column is desirable:

printf("%0 #*.*D(63,*)\n", (Len + 2), Prec, Prec, fulldec) ;

printf("%0+#*.*D(63,*)\n", (Len + 2), Prec, Prec, fulldec) ;


To avoid printing the decimal point for a zero-precision packed BCD [noting: the #flag in the above printf() examples would effect], then the alternative formatting shown below might be more appropriate; again, to ensure alignment within storage\report-column:

void printdec(void *A, int Len, int Prec)
{
decimal(63,0) fulldec ;
int offset, bytes , fmtLn ;

if (Prec) fmtLn=Len+2 ; // first byte is not a digit
else fmtLn=Len+1 ; // zero-precision: less one byte
bytes = (Len / 2) + 1;
offset = 32 - bytes;
fulldec = 0D;
memcpy(((char *) &fulldec) + offset, A, bytes);
printf("%0 *.*D(63,*)\n", fmtLn, Prec, Prec, fulldec) ;
//printf("%0+*.*D(63,*)\n", fmtLn, Prec, Prec, fulldec) ;
}

Some Example values for three variations of P(l,p) to exhibit the results using the [active\non-commented] format-string in the revised version of the printdec() included just above; if the version with the plus symbol [the commented version with the +flag] were to used instead, the first character as blank for positive values would be the plus-character instead of the blank:

P(09,2) P(03,0) P(06,6)
----------- ---- ---------
9876543.21 321 0.660000
-9876543.21 -321 -0.660000
0876543.21 001 0.000006
-0876543.21 -001 -0.000006
0000000.21 000 0.000000
-0000000.21
0000000.00