Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!cs.utexas.edu!bcm!shell!nuchat!abbadon
From: abbadon@nuchat.UUCP (David Neal)
Newsgroups: comp.lang.c
Subject: Re: Packed Decimal Conversion fns sought, TFM is silent
Summary: A quick routine
Keywords: PACKED DECIMAL IBM
Message-ID: <11810@nuchat.UUCP>
Date: 28 Jun 89 21:29:59 GMT
References: <223@eds1.UUCP>
Distribution: na
Organization: South Coast Computing Services, Inc. - Houston, Tx
Lines: 53



#include <stdio.h>


/* Routine to unpack BCD packed decimal into an integer. */

unpack(packed, length, unpacked)
char packed[];                  /* Array of chars containing packed number */
int length;                     /* Length of the array (not '\0' terminated) */
int *unpacked;                  /* Pointer to integer for return value */
{

  register int i, j;
  static char asciibuf[128];   /* Number cannot be > 63 digits in length */

  j = 0;
  length--;                    /* Decrement length; we always use length - 1
                                  because of the special case and because
                                  of 'C' array indices start at 0. */

  /* Run to length-1 bytes; last byte is a special case */

  for ( i = 0; i < length; i++ )
    {
      asciibuf[j++] = ( (packed[i] & 0xf0) >> 4 ) + 0x30;
      asciibuf[j++] =   (packed[i] & 0x0f)        + 0x30; 
 
                                    /* 0x30 is the delta between BCD nybble
				       x and it's ascii counterpart. */
    }

  asciibuf[j++] = ( (packed[length] & 0xf0) >> 4 ) + 0x30;
  asciibuf[j] = '\0';
  
  fprintf(stderr, "unpack: %s \n", asciibuf);

  *unpacked = atoi(asciibuf);

  /* Special case: If the last nybble is 0x0d, the number is negative */
  if ( (packed[length] & 0x0f) == 0x0d ) *unpacked *= -1;

}

Sorry about the wasted bandwith; this guys mail bounces
and he's tough to get on the phone! Please no flamage
about system dependant this or messy that; it's just
a quick hack to help the guy.


David Neal
abbadon@nuchat.UUCP
uunet!nuchat!abbadon killer!texbell!nuchat!abbadon