What is the simplest way in C to convert an EBCDIC-encoded string to its ASCII equivalent in-place.
The only characters that need to be converted are the space, alphanumerics, and from the set <=>()+-*/&|!$#@.,;%_?"
. All other characters can simply be replaced with .
.
The function signature will basically be:
void ebcdicToAscii (char *s);
At the moment, I'm leaning towards a series of lookup tables and multiple if
statements for the various EBCDIC sections, but I wonder if there's a better way.
Using the table from here, from the top of my head:
static const unsigned char e2a[256] = {
0, 1, 2, 3,156, 9,134,127,151,141,142, 11, 12, 13, 14, 15,
16, 17, 18, 19,157,133, 8,135, 24, 25,146,143, 28, 29, 30, 31,
128,129,130,131,132, 10, 23, 27,136,137,138,139,140, 5, 6, 7,
144,145, 22,147,148,149,150, 4,152,153,154,155, 20, 21,158, 26,
32,160,161,162,163,164,165,166,167,168, 91, 46, 60, 40, 43, 33,
38,169,170,171,172,173,174,175,176,177, 93, 36, 42, 41, 59, 94,
45, 47,178,179,180,181,182,183,184,185,124, 44, 37, 95, 62, 63,
186,187,188,189,190,191,192,193,194, 96, 58, 35, 64, 39, 61, 34,
195, 97, 98, 99,100,101,102,103,104,105,196,197,198,199,200,201,
202,106,107,108,109,110,111,112,113,114,203,204,205,206,207,208,
209,126,115,116,117,118,119,120,121,122,210,211,212,213,214,215,
216,217,218,219,220,221,222,223,224,225,226,227,228,229,230,231,
123, 65, 66, 67, 68, 69, 70, 71, 72, 73,232,233,234,235,236,237,
125, 74, 75, 76, 77, 78, 79, 80, 81, 82,238,239,240,241,242,243,
92,159, 83, 84, 85, 86, 87, 88, 89, 90,244,245,246,247,248,249,
48, 49, 50, 51, 52, 53, 54, 55, 56, 57,250,251,252,253,254,255
};
void ebcdicToAscii (unsigned char *s)
{
while (*s)
{
*s = e2a[(int) (*s)];
s++;
}
}
For your specific requirements, I would suggest something like:
#include <stdio.h>
void inSituEbcdicToAscii (char *s) {
static char etoa[] =
" "
" "
" .<(+|& !$*); " // first char here is real space
"-/ ,%_>? `:#@'=\""
" abcdefghi jklmnopqr "
" stuvwxyz "
" ABCDEFGHI JKLMNOPQR "
" STUVWXYZ 0123456789 ";
while (*s != '\0') {
*s = etoa[(unsigned char)*s];
s++;
}
}
int main (void) {
char str[] = "\xc8\x85\x93\x93\x96\x40\xa3\x88\x85\x99\x85\x5a";
inSituEbcdicToAscii (str);
printf ("%s\n", str);
return 0;
}
which outputs Hello there!
from the equivalent EBCDIC characters. All other characters beyond those you showed an interest in are converted to a space, though you can change that to something else (make sure you don't modify EBCDIC code 0x40
which is the real space).