// ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
//
//  Copyright (c) 2001-2003, Haiku
//
//  This software is part of the Haiku 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;
}