/* prints arbitrary input, converting non graphic characters to octal
 * or hex, at the users specification, and breaking long lines without
 * splitting words at a user specified width.
 */

#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

#define MAXWORD 100
#define DEFWIDTH 80 /* default maximum line width */
#define VISSTART 32 /* beginning of graphic character range */
#define VISSTOP 126 /* end of graphic character range */

struct flags_t {
     unsigned int is_hex : 1;
     unsigned int is_octal : 1;
} flags;


enum { ON, OFF };

/* isgraphic: returns 1 if character can be printed */
int isgraphic(char c) {

     if ((c >= VISSTART && c <= VISSTOP) || isspace(c))
	  return 1;

     return 0;
}

/* print s, converting to octal or hex if necessary */
void write(char *s) {

     while (*s != '\0') {
	  if (isgraphic(*s))
	       putchar(*s);
	  else
	       if (flags.is_hex)
		    printf("\\0x%.2x", *s);
	       else if (flags.is_octal)
		    printf("\\0%.3o", *s);
	       else  /* default to decimal */
		    printf("\\%.3d", *s);
	  s++;
     }
}

int main(int argc, char *argv[]) {
     char c, buf[MAXWORD];
     int bufi, len;
     int width = DEFWIDTH;
     
     /* get arguments */
     while (--argc && **++argv == '-') {
	  while ((c = *++argv[0]) != '\0') {
	       switch (c) {
	       case 'o':
		    flags.is_hex = OFF;
		    flags.is_octal = ON;
		    break;
	       case 'h':
		    flags.is_hex = ON;
		    flags.is_octal = OFF;
		    break;
	       case 'c':
		    argv++;
		    argc--;
		    if (argv[0] == NULL) {
			 printf("error: expected numeric argument\n");
			 exit(1);
		    }
		    width = atoi(argv[0]);
		    if (width == 0) {
			 printf("error: invalid numeric argument: %s\n", argv[0]);
			 exit(1);
		    }
		    
		    /* now we cheat a bit to break out of the while loop
		       and get on to processing any remaining arguments */
		    argv[0][1] = '\0';
		    break;
	       default:
		    printf("error: invalid option: -%s\n", argv[0]);
		    exit(1);
		    break;
	       }
	  }
     }
     if (argc != 0) { /* bad arguments! no soup for you! */
	  printf("error: invalid argument: %s\n", argv[0]);
	  exit(1);
     }

     bufi = len = 0;
     while ((c=getchar()) != EOF) {
	  if (isspace(c)) {
	       buf[bufi] = '\0';
	       write(buf);
	       bufi = 0;
	       buf[bufi] = '\0';
	       if (c == '\n')
		    len = 0;
	  }
	  if (bufi < MAXWORD - 1) /* truncate exceedingly large words */
	       buf[bufi++] = c;
	  if (!isgraphic(c)) { /* non-graphic characters take more space to represent */
	       if (flags.is_hex || flags.is_octal)
		    len += 5;
	       else
		    len += 4; /* decimal */
	  } else
	       len++;
	  if (len >= width) {
	       putchar('\n');
	       len = 0;
	  }
     }
     if (c != '\n') /* it's always nice to end with a newline */
	  putchar('\n');
	       
     return 0;
}