#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include "mystdlib.h"

static char xlat_table[] = {
  0x00, 0x09, 0x02, 0x03, 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b,
  0x2c, 0x2d, 0x2e, 0x2f, 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
  0x3c, 0x3d, 0x3e, 0x3f, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b,
  0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5f,
  0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f, 0x70,
  0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0xc7, 0xfc, 0xe9, 0xe2, 0xe4, 0xe0,
  0xe5, 0xe7, 0xea, 0xeb, 0xe8, 0xef, 0xee, 0xec, 0xc4, 0xc5, 0xc9, 0xe6, 0xc6, 0xf4, 0xf6, 0xf2,
  0xfb, 0xf9, 0xff, 0xd6, 0xdc, 0xe1, 0xed, 0xf3, 0xfa, 0xf1, 0xd1, 0xdf, 0x5b, 0x5c, 0x5d, 0x60
};

void decode_7bit_string( uint8_t const *source, uint8_t *dest )
{
  uint16_t acc = 0, acc_bits = 0;
  while( 1 )
  {
    acc = acc*256+*(source++); ++acc_bits;
again:
    *(dest++) = xlat_table[ 0x7f & ( acc >> acc_bits ) ];
    if( !dest[-1] ) return;
    if( acc_bits == 7 ) { acc_bits = 0; goto again; }
  }
}
int fromhex( uint8_t a ) { if(a >='0'&&a<='9')return a-'0';if(a>='a'&&a<='f') return 10+a-'a'; if(a>='A'&&a<='F') return 10+a-'A'; exit(1); }

void act_on_record( int flag, uint8_t *page, uint16_t record_off )
{
  uint8_t * record = page + record_off;
  uint8_t   outbuf[8192], * out_dest = outbuf;
  int       num_entries = *(uint16_t*)record;

  /* printf( "    Found record with %d entries at %04x.\n", num_entries, record_off ); */
  if( record_off > 0x1fff )
    return; /* Ignore deleted entries */

  if( !flag )
  { /* Flags says whether page has a prefix row */
    record += 2;
    if( *(uint16_t*)record )
    {
      decode_7bit_string( page + *(uint16_t*)record, outbuf );
      out_dest += strlen( (char*)outbuf );
    }
  }

  decode_7bit_string( record + 2, out_dest );
  /* XXX TODO: Split record in 12 chunks each, mark continuation, if num_entries > 1 */
  puts( (char*)outbuf );
}

/* Page is always 0x2000 */
void act_on_page( uint8_t *page, int page_nr )
{
  int record, flag  = page[0];
  int blob_len      = *(uint16_t*)(page + 0x2);
  int num_records   = *(uint16_t*)(page + 0x4);
  uint16_t * recs   =  (uint16_t*)(page + 0xe);

  printf( "  Acting on page %04d with flag %d and %04d records.\n", page_nr, flag, num_records );

  if( blob_len )
  {
    uint8_t outbuf[8192];
    /* printf( "-------- PAGE IS BLOB --------" ); */

    decode_7bit_string( page + 0x6, outbuf );
    /* XXX TODO: Split record in 12 chunks each, mark continuation */
    puts( (char *)outbuf );
  } else
    for( record = 0; record < num_records; ++record )
      act_on_record( flag, page + 0xe, recs[record] );
}

void act_on_file( uint8_t *file, size_t len )
{
  int page, num_pages = *(uint16_t*)(file+0x40);
  int num_records     = *(uint32_t*)(file+0x42);
  char *gasse         = (char *)file + 0x8e;
  char *ort           = gasse + 1 + strlen(gasse);
  char *zip           = ort   + 1 + strlen(ort);
  char *vorwahl       = zip   + 1 + strlen(zip);

  /* printf( "Working on a %04d page and %06d records file, city: %4s %-32s with prefix %s\n", num_pages, num_records, zip, ort, vorwahl ); */

  for( page = 0; page < num_pages; ++page )
    act_on_page( file + 0x800 + 0x2000 * page, page );
}

int main( int args, char **argv )
{
  MAP f = map_file( argv[1], 1 );

  act_on_file( f->addr, f->size );

  unmap_file( &f );
  return 0;
}