/* ebcdic2ascii.cpp
 *
 * convert an EBCDIC file to ASCII.
 *
 *
 * gcc -funsigned-char ebcdic2ascii.cpp
 *
 * Unsigned char else the array lookup will fail....
 */

#include <stdio.h>

char xlat_ebcdic_to_ascii[256] = {
   /*         0   1   2   3   4   5   6   7   8   9   A   B   C   D   
+E   F
    *        --- --- --- --- --- --- --- --- --- --- --- --- --- --- -
+-- --- */
   /* 0 */     1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 ,
+ 1 , 1 ,
   /* 1 */     1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 ,
+ 1 , 1 ,
   /* 2 */     1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 ,
+ 1 , 1 ,
   /* 3 */     1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 ,
+ 1 , 1 ,
   /* 4 */    ' ', 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 ,'?','.','<','(',
+'+','|',
   /* 5 */    '&', 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 ,'!','$','*',')',
+';','?',
   /* 6 */    '-','/', 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 ,'|',',','%','_',
+'>','?',
   /* 7 */     1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 ,'`',':','#','@','\''
+,'=','~',
   /* 8 */     1 ,'a','b','c','d','e','f','g','h','i', 1 , 1 , 1 , 1 ,
+ 1 , 1 ,
   /* 9 */     1 ,'j','k','l','m','n','o','p','q','r', 1 , 1 , 1 , 1 ,
+ 1 , 1 ,
   /* A */     1 ,'~','s','t','u','v','w','x','y','z', 1 , 1 , 1 , 1 ,
+ 1 , 1 ,
   /* B */     1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 ,
+ 1 , 1 ,
   /* C */    '{','A','B','C','D','E','F','G','H','I', 1 , 1 , 1 , 1 ,
+ 1 , 1 ,
   /* D */    '}','J','K','L','M','N','O','P','Q','R', 1 , 1 , 1 , 1 ,
+ 1 , 1 ,
   /* E */    '\\',0 ,'S','T','U','V','W','X','Y','Z', 1 , 1 , 1 , 1 ,
+ 1 , 1 ,
   /* F */    '0','1','2','3','4','5','6','7','8','9', 1 , 1 , 1 , 1 ,
+ 1 , 1
};

char tohex(char v) {
    // NOTE: if signed character, be sure it's not negative!  So ignor
+e the
    // warning, as it alerts you to a compile error (i.e. missing -fun
+signed-char)
    if ( (v<0) || (v>15) ) {
        return '#';
    }
    return "0123456789ABCDEF"[v];
}

// convert <src> to ascii, stick in <*dst> and return next position
char *ebcdic_to_ascii(char *dst, char src) {
    char x = xlat_ebcdic_to_ascii[src];
    *dst++ = x;
    return dst;
}

// convert <len> chars at <*src> to ascii, storing them at <*dst> and
// returning the next position
char *xlat(char *dst, char *src, int len) {
    while (len--) {
        dst = ebcdic_to_ascii(dst, *src++);
    }
    return dst;
}

char packed_to_ascii[] = "0123456789 -+-++";

// SIGNED unpack: show trailing sign
char *Sunpack(char *dst, char *src, int len, int skip=0) {

    // Skip digits as requested...
    while (skip > 1) {
        // Skip entire bytes
        ++src;
        skip -= 2;
        --len;
    }
    if (skip) {
        // Skip next digit (i.e. MSB)
        *dst++ = packed_to_ascii[ (*src++) & 0x0f ];
        --len;
    }

    // Emit remaining digits
    while (len--) {
        *dst++ = packed_to_ascii[ (*src>>4) & 0x0f ];
        *dst++ = packed_to_ascii[ (*src++) & 0x0f ];
    }
    return dst;
}

// UNSIGNED unpack: skip sign
char *Uunpack(char *dst, char *src, int len, int skip=0) {

    // Skip digits as requested...
    while (skip > 1) {
        // Skip entire bytes
        ++src;
        skip -= 2;
        --len;
    }
    if (skip) {
        // Skip next digit (i.e. MSB)
        *dst++ = packed_to_ascii[ (*src++) & 0x0f ];
        --len;
    }

    // Emit remaining digits, except for last byte
    while (len-- > 1) {
        *dst++ = packed_to_ascii[ (*src>>4) & 0x0f ];
        *dst++ = packed_to_ascii[ (*src++) & 0x0f ];
    }

    // For last byte, show MSB only (last digit before sign)
    *dst++ = packed_to_ascii[ (*src>>4) & 0x0f ];
    return dst;
}

#define IRECSIZE 500        // input record size
#define ORECSIZE 2048       // Room for translated/unpacked record

int main(int argc, char **argv) {

    if (argc != 3) {
        puts("Missing INFile or OUTFile!");
        return 1;
    }

    // Open the input and output files
    FILE *fin = fopen(argv[1], "rb");
    FILE *fout = fopen(argv[2], "w");
    if (!fin || !fout) {
        puts("Can't open a file!");
        return 2;
    }

    char inbuf[IRECSIZE+20];
    char outbuf[ORECSIZE];
    long recs = 0;

    while (!feof(fin)) {
        // Read the record
        size_t bytes_read = fread(inbuf, 1, IRECSIZE, fin);
        ++recs;
        if (IRECSIZE != bytes_read) {
            if (!bytes_read)
                printf("%lu: EOF detected?\n", recs);
            else
                printf("%lu: Sort record (saw %u, expected %u) found.\
+n",
                    recs, bytes_read, IRECSIZE);
            continue;
        }

        // Translate input fields into output buffer.
        char *dst = outbuf;
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