Apple dictionaries

0dedict.py

# Thanks to commenters for providing the base of this much nicer implementation!
# Save and run with $ python 0dedict.py
# You may need to hunt down the dictionary files yourself and change the awful path string below.
# This works for me on MacOS 10.14 Mohave

from struct import unpack
from zlib import decompress
import re
filename = '/System/Library/Assets/com_apple_MobileAsset_DictionaryServices_dictionaryOSX/9f5862030e8f00af171924ebbc23ebfd6e91af78.asset/AssetData/Oxford Dictionary of English.dictionary/Contents/Resources/Body.data'
f = open(filename, 'rb')

def gen_entry():
    f.seek(0x40)
    limit = 0x40 + unpack('i', f.read(4))[0]
    f.seek(0x60)
    while f.tell()<limit:
        sz, = unpack('i', f.read(4))
        buf = decompress(f.read(sz)[8:])

        pos = 0
        while pos < len(buf):
            chunksize, = unpack('i', buf[pos:pos+4])
            pos += 4

            entry = buf[pos:pos+chunksize]
            title = re.search('d:title="(.*?)"', entry).group(1)
            yield title, entry

            pos += chunksize

for word, definition in gen_entry():
    print(word)

dedict.c

// *** Old code - not needed given the python code above

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include "zlib.h"

#define CHUNK 16384

/*
 40 Length of the zlib stream
 4c 0020
 54 0275 number of blocks
 
 60 808c pointer to the next block
 64 8088 length of the first block
 68 047a4a length of the unpacked block
 6c start of the zlib stream
 
 80fc second block
 
 13cd134
 13cd174
*/
     
int unpack(unsigned char *in, int len)
{
  int ret,outed=0;
  unsigned have;
  z_stream strm;
  unsigned char out[CHUNK];
  
  strm.zalloc = Z_NULL;
  strm.zfree = Z_NULL;
  strm.opaque = Z_NULL;
  strm.avail_in = 0;
  strm.next_in = Z_NULL;
  ret = inflateInit(&strm);
  if (ret != Z_OK)
    return ret;
  strm.avail_in = len;
  strm.next_in = in;
  do {
    strm.avail_out = CHUNK;
    strm.next_out = out;
    ret = inflate(&strm, Z_NO_FLUSH);
    assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
    switch (ret) {
      case Z_NEED_DICT:
        ret = Z_DATA_ERROR;     /* and fall through */
      case Z_DATA_ERROR:
      case Z_MEM_ERROR:
        (void)inflateEnd(&strm);
        return ret;
    }
//    printf("%lx %x\n",strm.next_in-in,strm.avail_in);
    have = CHUNK - strm.avail_out /* - (outed?0:4)*/;

    int off = 0;
    /*
    while (have - off > 3 && out[off] != '<' && out[1+off] != 'd' && out[2+off] != ':') {
      ++off;
    }*/

    if (have - off <= 3) {
      fprintf(stderr, "could not find entry\n");
    }

    if (fwrite(out + off/*+(outed?0:4)*/, have - off, 1, stdout) != 1 || ferror(stdout)) {
      (void)inflateEnd(&strm);
      return Z_ERRNO;
    }
    //exit(0);

    outed+=have;
  } while (strm.avail_out == 0);
  printf("%06x\n",outed);
  (void)inflateEnd(&strm);
  return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
}

char filename[256];

int main(int argc,char **argv) {
  FILE *fin; int limit,blen=0,p,l,bcnt=0; unsigned char *buf=NULL;
  assert(argc >= 2);
  sprintf(filename,"/Library/Dictionaries/%s.dictionary/Contents/Body.data",argv[1]);
  if((fin=fopen(filename,"rb"))) {
    fseek(fin,0x40,SEEK_SET);
    fread(&l,1,4,fin);
    limit=0x40+l;
    p=0x60;
    do {
      fseek(fin,p,SEEK_SET);
      fread(&l,1,4,fin);
//      if(0==l) break;
      if(blen<l) {
        if(buf!=NULL) free(buf);
        blen=l;
        buf=(unsigned char *)malloc(blen);
      }
      fread(buf,1,l,fin);
      //fprintf(stderr, "%x@%06x: %x>%06x\n",bcnt,p,l,((int *)buf)[1]);
      unpack(buf+8,l-8);
      p+=4+l;
      ++bcnt;
    } while(p<limit);
    free(buf);
    fclose(fin);
  }
  return 0;
}

strip.c

// This program strips the first 4 characters from each line in the input
#include <stdio.h>

int main() {
  while(!ferror(stdin) && !feof(stdin)) {
    size_t len = 0;
    char *line = fgetln(stdin, &len);
    if (!line) break;

    if (len > 4)
      fwrite(line + 4, 1, len - 4, stdout);
  }

  return 0;
}

Way more up to date info here: https://fmentzer.github.io/posts/2020/dictionary/

I would like to extract morphological forms from binary AppleDict. I struggled with these files and didn't succeed:

EntryID.index
EntryID.data
KeyText.index
KeyText.data

If anyone succeeds deciphering those, I would be very grateful.

I was able to extract morphological forms from binary AppleDict (contained in KeyText.data) and exact article addresses from EntryID.data. Thank you @josephg and @fab-jul for inspiring me to do that.

On this pyglossary issue page you may find KeyText.data and EntryID.data format description in detail with code.

UPD (4 Mar 2023). We merged functionality that supports export of keys/indexing/morphology in AppleDict.

macOS 12.6.3
The folder is: /System/Library/AssetsV2/com_apple_MobileAsset_DictionaryServices_dictionaryOSX