/* xd.c : hexdump utility with real-time output
 * Jon Mayo - September 13, 2006 - PUBLIC DOMAIN
 */
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>

static int
	verbose=1, /* verbose messages (default) */
	fancy=1, /* fancy output */
	outbase=16, /* number base for output, 8, 10, or 16 */
	hexcase=1, /* select lower(0) or upper(1) case */
	max_length=0,
	skip_offset=0,
	output_buffering=0; /* should output be flushed constantly? */


static int xd(FILE *in, FILE *out, const char *name, int base) {
	int len, i, ch;
	unsigned char buf[16];
	int total=0;

	if(!output_buffering)
		setvbuf(out, 0, _IONBF, 0);

	if(skip_offset>0) {
		if(verbose>1) {
			fprintf(stderr, "%s:skipping %d bytes.\n", name, skip_offset);
		}
		if(fseek(in, SEEK_SET, skip_offset)==-1) {
			if(errno==EINVAL) {
				if(verbose) 
					fprintf(stderr, "%s:is a stream skipping by reading... \n", name);
				while(fgetc(in)!=EOF && base<skip_offset) base++;
			} else {
				perror(name);
				return 0;
			}
		} else {
			base+=skip_offset;
		}
	}
	if(max_length>0 && verbose>1) {
		fprintf(stderr, "%s:limiting length to %d bytes.\n", name, max_length);
	}
	ch=EOF;
	do {
		for(len=0;len<16 && (!max_length || total<max_length);len++, total++) {
			ch=fgetc(in);
			if(ch==EOF) {
				if(ferror(in)) {
					if(verbose) {
						fprintf(stderr, "\n%s:%s\n", name, strerror(errno));
					}
					return 0;
				}
				break;
			}
			buf[len]=ch;
			
			if(len==0) {
				if(hexcase)
					fprintf(out, "%06X:", base);
				else
					fprintf(out, "%06x:", base);
			}
			if(fancy) {
				if((len)==4 || (len)==12) {
					fprintf(out, ".");
				} else if((len)==8) {
					fprintf(out, "-"); 
				} else {
					fprintf(out, " ");
				}
			} else {
				fprintf(out, " ");
			}
			if(outbase==8) {
				fprintf(out, "%03o", buf[len]);
			} else if(outbase==10) {
				fprintf(out, "%03u", buf[len]);
			} else {
				if(hexcase)
					fprintf(out, "%02X", buf[len]);
				else
					fprintf(out, "%02x", buf[len]);
			}
		}
		for(i=len;i<sizeof buf;i++) {
			fprintf(out, "   ");
		}
		if(fancy) {
			fprintf(out, " | ");
		} else {
			fprintf(out, " ");
		}
		for(i=0;i<len;i++) {
			fprintf(out, "%c", isprint(buf[i])?buf[i]:'.');
		}
		fprintf(out, "\n");
		base+=16;
	} while(ch!=EOF && (!max_length || total<max_length));
	if(verbose) fprintf(stderr, "%s: %d bytes\n", name, total);
	return 1;
}

int main(int argc, char **argv) {
	int ch, argi, quiet=0;

	while((ch=getopt(argc, argv, "hVvqxXdofbs:l:"))!=-1) {
		switch(ch) {
			case 'V':
				printf(__FILE__ ":version 1.0 (" __DATE__ ")\n");
				return EXIT_SUCCESS;
			case 'v':
				verbose++;
				break;
			case 'q':
				quiet=1;
				break;
			case 'x':
				outbase=16;
				hexcase=0;
				break;
			case 'X':
				outbase=16;
				hexcase=1;
				break;
			case 'o':
				outbase=8;
				break;
			case 'd':
				outbase=10;
				break;
			case 'b': 
				fancy=0;
				break;
			case 'f':
				fancy++;
				break;
			case 's':
				skip_offset=strtol(optarg, 0, 0);
				break;
			case 'l':
				max_length=strtol(optarg, 0, 0);
				break;
			case 'B':
				output_buffering=1;
				break;
			case 'h':
			default:
				fprintf(stderr, "usage: %s [-hVvqxXdo] [-s skip] [-l length] [file ...]\n"
				"-h\thelp/usage\n"
				"-V\tversion info\n"
				"-v\tverbose messages\n"
				"-q\tquiet (override verbose)\n"
				"-X\tHexidecimal output (uppercase)\n"
				"-x\tHexidecimal output (lowercase)\n"
				"-d\tDecimal output\n"
				"-o\tOctal output\n"
				"-b\tBasic output (not fancy)\n"
				"-B\tenable output buffering\n"
				"-f\tFancy output (default)\n"
				"-s ofs\tskip to offset\n"
				"-l len\tlimit length to len bytes\n", argv[0]); 
				return EXIT_FAILURE;
		}
	}
	if(quiet) verbose=0;

	if(optind==argc) {
		if(!xd(stdin, stdout, "stdin", 0)) {
			return EXIT_FAILURE;
		}
	} else {
		for(argi=optind;argi<argc;argi++) {
			FILE *f;
			f=fopen(argv[argi], "rb");
			if(!f) {
				perror(argv[argi]);
				return EXIT_FAILURE;
			}
			if(verbose>1) 
				printf("%s:opening\n", argv[argi]);
			else if(verbose) 
				fprintf(stderr, "%s:opening\n", argv[argi]);

			if(!xd(f, stdout, argv[argi], 0)) {
				fclose(f);
				return EXIT_FAILURE;
			}
			fclose(f);
		}
	}
	return 0;
}