// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
//
//  Copyright (c) 2001-2003, OpenBeOS
//
//  This software is part of the OpenBeOS distribution and is covered 
//  by the MIT License.
//
//
//  File:        hd.c
//  Author:      Daniel Reinhold (danielre@users.sf.net)
//  Description: hex dump utility
//
// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

#include <OS.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <sys/stat.h>


void  display   (uint32, uint8 *);
void  do_hd     (char *);
void  dump_file (FILE *);
char *hexbytes  (uint8 *);
char *printable (uint8 *);
void  usage     (void);


static int BytesBetweenSpace = 1;


void
usage ()
{
	printf ("Usage:\thd [-n N] [file]\n");
	printf("\t-n expects a number between 1 and 16 and specifies\n");
    printf("\tthe number of bytes between spaces.\n");
    printf("\n\tIf no file is specified, input is read from stdin\n");
}


int
main(int argc, char *argv[])
{
	char *arg = NULL;
	
	if (argc == 1)
		dump_file(stdin);
	
	else {
		char *first = *++argv;
		
		if (strcmp(first, "--help") == 0) {
			usage();
			return 0;
		}
		
		if (strcmp(first, "-n") == 0) {
			if (--argc > 1) {
				char *num = *++argv;
				
				if (!isdigit(*num))
					printf("-n option needs a numeric argument\n");
				else {
					int b = atoi(num);
					
					if (b < 1)  b = 1;
					if (b > 16) b = 16;
					BytesBetweenSpace = b;
					
					if (--argc > 1)
						arg = *++argv;
					else
						printf("no file specified\n");
				}
			}
			else
				printf("-n option needs a numeric argument\n");
		}
		else
			arg = first;
		
		if (arg)
			do_hd(arg);
	}
	
	putchar('\n');
	return 0;
}


void
do_hd(char *fname)
{
	struct stat e;
	
	if (stat(fname, &e) == -1) {
		fprintf(stderr, "'%s': no such file or directory\n", fname);
		return;
	}

	if (S_ISDIR(e.st_mode))
		fprintf(stderr, "'%s' is a directory\n", fname);
	else {
		FILE *fp = fopen(fname, "rb");
		if (fp) {
			dump_file(fp);
			fclose(fp);
		}
		else
			fprintf(stderr, "'%s': %s\n", fname, strerror(errno));
	}
}


void
dump_file(FILE *fp)
{
	size_t got;
	uint32 offset = 0;
	uint8  data[16];
	
	while ((got = fread(data, 1, 16, fp)) == 16) {
		display(offset, data);
		offset += 16;
	}
	
	if (got > 0) {
		memset(data+got, ' ', 16-got);
		display(offset, data);
	}
}


void
display(uint32 offset, uint8 *data)
{
	printf("%08" B_PRIx32 " ", offset);
	printf("  %s ", hexbytes(data));
	printf("%16s ", printable(data));
	
	putchar('\n');
}


char *
hexbytes(uint8 *s)
{
	static char buf[64];
	char *p = buf;
	uint8 c;
	int   i;
	int   n = 0;
	
	for (i = 0; i < 16; ++i) {
		c = *s++;
		*p++ = "0123456789abcdef"[c/16];
		*p++ = "0123456789abcdef"[c%16];
		
		if (++n == BytesBetweenSpace) {
			*p++ = ' ';
			n = 0;
		}
		
		if ((i == 7) && (BytesBetweenSpace == 1))
			*p++ = ' ';
	}
	*p++ = ' ';
	*p = 0;
	
	return buf;
}


char *
printable (uint8 *s)
{
	static char buf[16];
	char *p = buf;
	uint8 c;
	int   i = 16;
	
	while (i--) {
		c = *s++;
		*p++ = (isgraph(c) ? c : '.');
	}
	*p = 0;
	
	return buf;
}