#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <err.h>

#include "byteorder.h"

#define PSTRING_LEN 1024
#define FSTRING_LEN 256

#define uint16 unsigned short

typedef char pstring[PSTRING_LEN];
typedef char fstring[FSTRING_LEN];

/* pointer difference macro */
#define PTR_DIFF(p1,p2) ((unsigned int)(((const char *)(p1)) - (const char *)(p2)))

/****************************************************************************
 Return the total storage length of a mangled name.
****************************************************************************/

int name_len(char *s1)
{
	/* NOTE: this argument _must_ be unsigned */
	unsigned char *s = (unsigned char *)s1;
	int len;

	/* If the two high bits of the byte are set, return 2. */
	if (0xC0 == (*s & 0xC0))
		return(2);

	/* Add up the length bytes. */
	for (len = 1; (*s); s += (*s) + 1) {
		len += *s + 1;
		//SMB_ASSERT(len < 80);
		if(len < 80) {
		    fprintf(stderr, "Assert: len < 80; %d\n", len);
		}
	}

	return(len);
}

/****************************************************************************
 Find a pointer to a netbios name.
****************************************************************************/

static char *name_ptr(char *buf,int ofs)
{
	unsigned char c = *(unsigned char *)(buf+ofs);

	if ((c & 0xC0) == 0xC0) {
		uint16 l = RSVAL(buf, ofs) & 0x3FFF;
		fprintf(stderr, "name ptr to pos %d from %d is %s\n",l,ofs,buf+l);
		return(buf + l);
	} else {
		return(buf+ofs);
	}
}  

/****************************************************************************
 Interpret the weird netbios "name" into a unix fstring. Return the name type.
****************************************************************************/

static int name_interpret(char *in, fstring name)
{
	int ret;
	int len = (*in++) / 2;
	fstring out_string;
	char *out = out_string;

	*out=0;

	if (len > 30 || len<1)
		return(0);

	while (len--) {
		if (in[0] < 'A' || in[0] > 'P' || in[1] < 'A' || in[1] > 'P') {
			*out = 0;
			return(0);
		}
		*out = ((in[0]-'A')<<4) + (in[1]-'A');
		in += 2;
		out++;
	}
	ret = out[-1];
	out[-1] = 0;

#ifdef NETBIOS_SCOPE
	/* Handle any scope names */
	while(*in) {
		*out++ = '.'; /* Scope names are separated by periods */
		len = *(unsigned char *)in++;
		StrnCpy(out, in, len);
		out += len;
		*out=0;
		in += len;
	}
#endif
	//pull_ascii_fstring(name, out_string);
	strcpy(name, out_string);

	return(ret);
}

/****************************************************************************
 Extract a netbios name from a buf (into a unix string) return name type.
****************************************************************************/

int name_extract(char *buf,int ofs, fstring name)
{
	char *p = name_ptr(buf,ofs);
	int d = PTR_DIFF(p,buf+ofs);

	name[0] = '\0';
	if (d < -50 || d > 50)
		return(0);
	return(name_interpret(p,name));
}

int main(int argc, char *argv[]) {
    int fd, len;
    char buf[4096];
    fstring name1, name2;
    
    *name1 = *name2 = 0;
    
    fd=open(argv[1], O_RDONLY);
    if(fd < 0) {
	err(1, "Failed to open the file");
    }
    read(fd, buf, sizeof(buf));
    
    close(fd);
    
    len = name_len(buf+4);
    
    printf("Len: %d\n", len);
    
    name_extract(buf,4,name1);
    
    printf("|%s|\n", name1);

    name_extract(buf,4 + name_len(buf + 4),name2);

    printf("|%s|\n", name2);

}