Converting EBCDIC to ASCII

Converting EBCDIC to ASCII

There's still a need to convert data stored in IBM's EBCDIC (Extended Binary-Coded Decimal Interchange Code) format to the more common ASCII (American Standard Code for Information Interchange). Occasionally it's necessary to do the opposite. This little filter converts in either direction.

/* ==========================================================
   Op/System : Unix
   Job Name : e2a
   Module : e2a.c
   Purpose : Reads standard input and converts the stream
   from EBCDIC to ASCII
   sending it to standard output.
   Compilation : cc -o e2a e2a.c
   Parameters : E = Convert from EBCDIC to ASCII (default)
   A = Convert from ASCII to EBCDIC
   Usage : cat source.file | e2a E >target.file
   ======================================================== */
#include <sys/types.h>
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

static unsigned char a2e[256] = {
0, 1, 2, 3, 55, 45, 46, 47, 22, 5, 37, 11, 12, 13, 14, 15,
16, 17, 18, 19, 60, 61, 50, 38, 24, 25, 63, 39, 28, 29, 30, 31,
64, 79,127,123, 91,108, 80,125, 77, 93, 92, 78,107, 96, 75, 97,
240,241,242,243,244,245,246,247,248,249,122, 94, 76,126,110,111,
124,193,194,195,196,197,198,199,200,201,209,210,211,212,213,214,
215,216,217,226,227,228,229,230,231,232,233, 74,224, 90, 95,109,
121,129,130,131,132,133,134,135,136,137,145,146,147,148,149,150,
151,152,153,162,163,164,165,166,167,168,169,192,106,208,161, 7,
32, 33, 34, 35, 36, 21, 6, 23, 40, 41, 42, 43, 44, 9, 10, 27,
48, 49, 26, 51, 52, 53, 54, 8, 56, 57, 58, 59, 4, 20, 62,225,
65, 66, 67, 68, 69, 70, 71, 72, 73, 81, 82, 83, 84, 85, 86, 87,
88, 89, 98, 99,100,101,102,103,104,105,112,113,114,115,116,117,
118,119,120,128,138,139,140,141,142,143,144,154,155,156,157,158,
159,160,170,171,172,173,174,175,176,177,178,179,180,181,182,183,
184,185,186,187,188,189,190,191,202,203,204,205,206,207,218,219,
220,221,222,223,234,235,236,237,238,239,250,251,252,253,254,255
} ;

static 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
} ;

/* ---------------------------------------------------
Pass this function one ASCII character
and receive back the equivalent EBCDIC character...
------------------------------------------------ */
unsigned char ASCIItoEBCDIC(const unsigned char c)
{
return a2e[c];
}

/* ---------------------------------------------------
Pass this function one EBCDIC character and receive
the equivalent ASCII character in return...
------------------------------------------------ */
unsigned char EBCDICtoASCII(const unsigned char c)
{
return e2a[c];
}

int main(int argc, char **argv)
{
char Mode;
unsigned char InChar;

/* ------------------------------------------------------
Get the operation type (default is EBCDIC to ASCII)...
--------------------------------------------------- */
if(argc == 1)
Mode = 'E';
else
Mode = *argv[1];

/* -----------------------------
Check we have a valid mode...
-------------------------- */
if(Mode != 'E' && Mode != 'A')
{
printf("Usage: cat <filename> | e2a [E|A]\n");
printf("Where E = convert from EBCDIC to ASCII (default)\n");
printf(" A = convert from ASCII to EBCDIC\n");
exit(-1);
}

/* --------------------------------
Still here? Do the conversion...
----------------------------- */
while(!feof(stdin))
{
InChar = (char) getchar();
if(Mode == 'E')
putchar(EBCDICtoASCII(InChar));
else
putchar(ASCIItoEBCDIC(InChar));
}
}
/* ===========================================
   END END END END END END END END END END END
   ======================================== */