/*
 * compaction.c
 */

#include <sys/types.h>
#include <netinet/in.h>


char            uncompact_table[7][16] = {
   0, ' ', '\n', 'a', 'e', 'h', 'i',
   'n', 'o', 's', 't', 1, 2, 3,
   4, 5, 'b', 'c', 'd', 'f', 'g',
   'j', 'k', 'l', 'm', 'p', 'q', 'r',
   'u', 'v', 'w', 'x', 'y', 'z', 'A',
   'B', 'C', 'D', 'E', 'F', 'G', 'H',
   'I', 'J', 'K', 'L', 'M', 'N', 'O',
   'P', 'Q', 'R', 'S', 'T', 'U', 'V',
   'W', 'X', 'Y', 'Z', '!', '"', '#',
   '@', '~', '&', 39, '(', ')', '*',
   '+', ',', '-', '.', '/', '0', '1',
   '2', '3', '4', '5', '6', '7', '8',
   '9', ':', ';', '<', '=', '>', '?',
   '[', '\\', ']', '^', 6, '`', '_',
   '{', '|', '}', '%', '$', -1, 0,
0, 0, 0, 0, 0, 0, 0};

char            compact_table[128] = {
   1, 60, 61, 62, 102, 101, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80,
   81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 63, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46,
   47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 91, 92, 93, 94, 97, 96, 3, 16, 17, 18, 4,
   19, 20, 5, 6, 21, 22, 23, 24, 7, 8, 25, 26, 27, 9, 10, 28, 29, 30, 31, 32, 33, 98, 99, 100, 64
};


/* stores a nibble */

char           *store_nibble(char *dest, int n)
{
   static int      toggle = 0;
   if (toggle)
   {
      *dest++ |= (char) n;
      toggle = 0;
   } else
   {
      if (!n)
      {
	 *dest = 0;
	 dest++;
	 return dest;
      }
      n <<= 4;
      *dest = (char) n;
      toggle = 1;
   }
   return dest;
}

/* retrieves a nibble */

char           *get_nibble(int *n, char *source)
{
   static int      toggle = 0;
   if (toggle)
   {
      *n = ((int) *source++) & 15;
      toggle = 0;
   } else
   {
      *n = (((int) *source) >> 4) & 15;
      if (!*n)
	 source++;
      else
	 toggle = 1;
   }
   return source;
}

/* returns new source */

char           *get_string(char *dest, char *source)
{
   char            c = 1;
   int             n = 0, table = 0;

   for (; c; table = 0)
   {
      c = 1;
      while (c && c < 7)
      {
	 source = get_nibble(&n, source);
	 c = uncompact_table[table][n];
	 if (c && c < 7)
	    table = (int) c;
      }
      *dest++ = c;
   }
   return source;
}

/* returns new destination */

char           *store_string(dest, source)
   char           *dest, *source;
{
   int             n, row, tmp = 1;
   for (; tmp; source++)
   {
      tmp = (int) *source;
      switch (tmp)
      {
	 case 0:
	    row = 0;
	    n = 0;
	    break;
	 case '\n':
	    row = 0;
	    n = 2;
	    break;
	 case -1:
	    row = 6;
	    n = 7;
	    break;
	 default:
	    row = (compact_table[tmp - 32]) >> 4;
	    n = (compact_table[tmp - 32]) & 15;
	    break;
      }
      switch (row)
      {
	 case 0:
	    dest = store_nibble(dest, n);
	    break;
	 case 1:
	    dest = store_nibble(dest, 11);
	    dest = store_nibble(dest, n);
	    break;
	 case 2:
	    dest = store_nibble(dest, 12);
	    dest = store_nibble(dest, n);
	    break;
	 case 3:
	    dest = store_nibble(dest, 13);
	    dest = store_nibble(dest, n);
	    break;
	 case 4:
	    dest = store_nibble(dest, 14);
	    dest = store_nibble(dest, n);
	    break;
	 case 5:
	    dest = store_nibble(dest, 15);
	    dest = store_nibble(dest, n);
	    break;
	 case 6:
	    dest = store_nibble(dest, 15);
	    dest = store_nibble(dest, 15);
	    dest = store_nibble(dest, n);
	    break;
      }
   }
   return dest;
}

/* store 2-byte word in player file */

char           *store_word(dest, source)
   char           *dest;
   int             source;
{
   *dest++ = (source >> 8) & 255;
   *dest++ = source & 255;
   return dest;
}

/* store 4-byte word in player file */

char           *store_int(dest, source)
   char           *dest;
   int             source;
{
   int             i;
   union
   {
      char            c[4];
      int             i;
   }               u;
   u.i = htonl(source);
   for (i = 0; i < 4; i++)
      *dest++ = u.c[i];
   return dest;
}

/* retrieve 2-byte word from player file */

char           *get_word(dest, source)
   char           *source;
   int            *dest;
{
   union
   {
      char            c[4];
      int             i;
   }               u;
   u.i = 0;
   u.c[3] = *source++;
   u.c[4] = *source++;
   *dest = ntohl(u.i);
   return source;
}

/* retrieve 4-byte int from player file */

char           *get_int(dest, source)
   char           *source;
   int            *dest;
{
   int             i;
   union
   {
      char            c[4];
      int             i;
   }               u;
   for (i = 0; i < 4; i++)
      u.c[i] = *source++;
   *dest = ntohl(u.i);
   return source;
}