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

-- 
Regards, Chuck
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