86 lines
2.6 KiB
C
86 lines
2.6 KiB
C
|
/*****************************************************************************
|
||
|
|
MakDBf()
|
||
|
|
This function converts a binary number to it's ASCII equivalent.
|
||
|
|
The resultant ASCII string is left in the digit buffer DBfBeg. The second
|
||
|
|
argument to this function specifies the radix to be used. If the radix is
|
||
|
|
decimal, then a minus sign will be prepended to the number if it is negative.
|
||
|
|
If the radix is not decimal, then minus sign are never prepended.
|
||
|
|
The recursive algorithm for base 10 conversion comes from "C Traps and
|
||
|
|
Pitfalls" by Andrew Koenig. In the "portability problems" section, the book
|
||
|
|
discusses common problems converting binary numbers to characters. One such
|
||
|
|
problem arises when the maximum negative number is presented to a conversion
|
||
|
|
algorithm. Many algorithms don't handle this well, including the one that
|
||
|
|
I used to use here. So I stole his, which avoids the problem and is also
|
||
|
|
impervious to the character collating sequence. I liked using recursion to
|
||
|
|
order the string so much that I made the base 8 and 16 code use it too.
|
||
|
|
*****************************************************************************/
|
||
|
|
#include "zport.h" /* define portability identifiers */
|
||
|
|
#include "tecoc.h" /* define general identifiers */
|
||
|
|
#include "defext.h" /* define external global variables */
|
||
|
|
#if USE_PROTOTYPES
|
||
|
|
static VVOID DoHex(ULONG n);
|
||
|
|
static VVOID DoOct(ULONG n);
|
||
|
|
static VVOID DoNeg(LONG n);
|
||
|
|
#endif
|
||
|
|
static char digits[] = "0123456789ABCDEF";
|
||
|
|
static VVOID DoHex(n)
|
||
|
|
ULONG n;
|
||
|
|
{
|
||
|
|
if (n != 0) {
|
||
|
|
DoHex(n >> 4);
|
||
|
|
*DBfPtr++ = digits[(int) n & 0x000f];
|
||
|
|
}
|
||
|
|
}
|
||
|
|
static VVOID DoOct(n)
|
||
|
|
ULONG n;
|
||
|
|
{
|
||
|
|
if (n != 0) {
|
||
|
|
DoOct(n >> 3);
|
||
|
|
*DBfPtr++ = digits[(int) n & 0x0007];
|
||
|
|
}
|
||
|
|
}
|
||
|
|
/*
|
||
|
|
* Put the character representation for the negative number n into DBf
|
||
|
|
*/
|
||
|
|
static VVOID DoNeg(n)
|
||
|
|
LONG n;
|
||
|
|
{
|
||
|
|
LONG quotient;
|
||
|
|
DEFAULT remainder;
|
||
|
|
quotient = n / 10;
|
||
|
|
remainder = (int) (n % 10); /* trailing digit */
|
||
|
|
if (remainder > 0) { /* on some machines, remainder might be positive */
|
||
|
|
remainder -= 10;
|
||
|
|
quotient++;
|
||
|
|
}
|
||
|
|
if (n <= -10)
|
||
|
|
DoNeg(quotient);
|
||
|
|
*DBfPtr++ = digits[-remainder];
|
||
|
|
}
|
||
|
|
VVOID MakDBf(Binary, NRadix) /* make digit buffer (DBfBeg) */
|
||
|
|
LONG Binary; /* binary number to be converted */
|
||
|
|
DEFAULT NRadix; /* radix to be used: 8, 10 or 16 */
|
||
|
|
{
|
||
|
|
ULONG TmpBin;
|
||
|
|
DBfPtr = DBfBeg; /* initialize digit buffer ptr */
|
||
|
|
if (Binary == 0) { /* simple case? */
|
||
|
|
*DBfPtr++ = '0';
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
if (NRadix == 10) {
|
||
|
|
if (Binary < 0) {
|
||
|
|
*DBfPtr++ = '-';
|
||
|
|
DoNeg(Binary);
|
||
|
|
} else {
|
||
|
|
DoNeg(-Binary);
|
||
|
|
}
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
TmpBin = Binary;
|
||
|
|
if (NRadix == 8) {
|
||
|
|
DoOct(TmpBin);
|
||
|
|
} else {
|
||
|
|
DoHex(TmpBin);
|
||
|
|
}
|
||
|
|
}
|