#include "alloc.h"
#include "byte.h"
#include "case.h"
#include "dnsresolv.h"

/**
	@file dns_domain.c
	@author djb
	@ref ucspi-tcp
	@brief domain qualification
*/

unsigned int dns_domain_length(const char *dn)
{
  const char *x;
  unsigned char c;

  x = dn;
  while ((c = *x++)) x += (unsigned int)c;
  return x - dn;
}

void dns_domain_free(char **out)
{
  if (*out) {
    alloc_free(*out);
    *out = 0;
  }
}

int dns_domain_copy(char **out, const char *in)
{
  unsigned int len;
  char *x;

  len = dns_domain_length(in);
  x = alloc(len);
  if (!x) return 0;
  byte_copy(x, len, in);
  if (*out) alloc_free(*out);
  *out = x;
  return 1;
}

int dns_domain_equal(const char *dn1, const char *dn2)
{
  unsigned int len;

  len = dns_domain_length(dn1);
  if (len != dns_domain_length(dn2)) return 0;

  if (case_diffb((char *)dn1, len, (char *)dn2)) return 0; /* safe since 63 < 'A' */
  return 1;
}

int dns_domain_suffix(const char *big, const char *little)
{
  unsigned char c;

  for (;;) {
    if (dns_domain_equal(big, little)) return 1;
    c = *big++;
    if (!c) return 0;
    big += c;
  }
}

unsigned int dns_domain_suffixpos(const char *big, const char *little)
{
  const char *orig = big;
  unsigned char c;

  for (;;) {
    if (dns_domain_equal(big, little)) return big - orig;
    c = *big++;
    if (!c) return 0;
    big += c;
  }
}