/* phone.c: Format and store telephone numbers               */
/* Copyright (C) J.G.Harston, 2002-2005                      */
/* version 1.00                                              */


/* char *phone_format(char *string, int zone)
   on entry:
     string = raw telephone number string
     zone   = pass as zero in this version
   on exit:
     returns formatted telephone number string

   The passed string is stripped of all any any invalid characters
   and a telephone number string correctly formatted for the UK
   telephone numbering system is returned. The formatted telephone
   number string is returned stored in the memory the passed string
   is stored in. That memory must have enough space to store 16
   characters including terminator.

   The zone parameter is reserved for future versions to specify
   the telephone numbering zone to use.
 */

char *phone_format(char *s, int z) {
  char *s1, *s2;
  int n1, n2;

  s1=s;
  while (*s1) {
    if (*s1>='0' && *s1<='9') *s2++=*s1;	// Strip out non-digits
    s1++;
  }
  *s2=0;

  if (z!=0 && z!=44)   return s;		// Not default or UK
  if (s[0]!='0')	   return s;		// Not 0xxx
  if (s[1]=='0')	   return s;		// 00xxx
  if (strlen(s)!=11)	   return s;		// Not 0xxxxxxxxxx

  n1=3; n2=5;					   // 0xxx xxx-xxxx default
  if (s[1]=='2')		   { n1=4; n2=5; } // 02x xxxx-xxxx
  if (s[1]=='1' && s[2]!='1' && s[3]!='1')
				   { n1=0; n2=7; } // 01xxx xxxxxx

  s1=s+strlen(s)+1;		// Point to end of source string
  s2=s+n1+n2+1;			// Point to dest to copy string to
  while(n2--) *s2--=*s1--;	// Copy second component and '\0' terminator
  if (n1)     *s2--='-';	// Hyphenate long numbers
  while(n1--) *s2--=*s1--;	// Copy first component
  *s2=' ';			// Space after dialling code

  return s;
}