Category : C Source Code
Archive   : CSRC2.ZIP
Filename : ASCR50.C

 
Output of file : ASCR50.C contained in archive : CSRC2.ZIP
/*
* a s c r 5 0 . c
*/

/*)LIBRARY
*/

#ifdef DOCUMENTATION

title ascr50 Ascii to Radix 50
index Ascii to radix 50

synopsis
.s.nf

ascr50(count, input, output)
int count;
int *output;
char *input;

description

Convert 'count' characters from Ascii to Radix 50. If there aren't a
multiple of 3 characters, blanks are padded on the end. The Ascii
string is moved to the output when finished. The input and output
areas may be the same since three input characters are read for
every two bytes of output.

bugs

#endif

#ifdef pdp11
#define SHORT unsigned
#else
#define SHORT unsigned short
#endif

#ifdef OLD_CODE

struct table {
char low, high;
int magic;
};

static struct table r50tab[] = {
{ 'a', 'z', -0140 },
{ 'A', 'Z', -0100 },
{ '0', '9', -0022 },
{ ' ', ' ', -0040 },
{ '$', '$', -0011 },
{ '.', '.', -0022 },
{ 0, 0, 0 },
};

ascr50(count, input, output)
int count; /* Characters to convert */
char *input; /* Input string (ascii) */
SHORT int *output; /* Output vector (rad50) */
{
register char *wp; /* Work area pointer */
register int byte; /* Working byte */
register struct table *rp; /* Rad50 table pointer */
int result; /* Rad50 work -- gets value */
char work[3+1]; /* Gets next three bytes */

for (;;) {
work[0] = work[1] = work[2] = ' ';
for (wp = work; --count >= 0;) {
*wp++ = *input++; /* Get one input byte */
if (wp >= &work[3])
break;
}
if (wp == work)
return; /* Nothing left to do */
/*
* Convert 3 bytes (in word) to rad50
*/
result = 0;
for (wp = work; wp < &work[3];) {
byte = *wp++ & 0377;
for (rp = r50tab; rp->low > 0; rp++) {
if (byte >= rp->low && byte <= rp->high)
break;
}
if (rp->low == 0)
byte == 0;
byte += rp->magic;
result <<= 3;
byte += result;
result <<= 2;
result += byte;
}
*output++ = result;
}
}

#else

/*
* Dave Conroy's algorithm
*/

ascr50(count, input, output)
int count; /* Characters to convert */
register char *input; /* Input string (ascii) */
register SHORT int *output; /* Output vector (rad50) */
{
register int r50;

while (--count >= 0) {
r50 = 050 * 050 * r50char(*input++);
r50 += 050 * r50char(*input++);
r50 += r50char(*input++);
*output++ = r50;
}
}

static int
r50char(c)
register int c;
{
if (c == ' ')
return (0);
if (c >= 'A' && c <= 'Z')
return (c - 'A' + 01);
if (c >= 'a' && c <= 'z')
return (c - 'a' + 01);
if (c == '$')
return (033);
if (c == '.')
return (034);
if (c >= '0' && c <= '9')
return (c - '0' + 036);
return (035);
}

#endif


  3 Responses to “Category : C Source Code
Archive   : CSRC2.ZIP
Filename : ASCR50.C

  1. Very nice! Thank you for this wonderful archive. I wonder why I found it only now. Long live the BBS file archives!

  2. This is so awesome! 😀 I’d be cool if you could download an entire archive of this at once, though.

  3. But one thing that puzzles me is the “mtswslnkmcjklsdlsbdmMICROSOFT” string. There is an article about it here. It is definitely worth a read: http://www.os2museum.com/wp/mtswslnk/