Function deflateSetDictionary

zlib/deflate.c:315–354

========================================================================= */

(strm, dictionary, dictLength)

/* ========================================================================= */
int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
    z_streamp strm;
    const Bytef *dictionary;
    uInt  dictLength;
{
    deflate_state *s;
    uInt length = dictLength;
    uInt n;
    IPos hash_head = 0;

    if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
        strm->state->wrap == 2 ||
        (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
        return Z_STREAM_ERROR;

    s = strm->state;
    if (s->wrap)
        strm->adler = adler32(strm->adler, dictionary, dictLength);

    if (length < MIN_MATCH) return Z_OK;
    if (length > MAX_DIST(s)) {
        length = MAX_DIST(s);
        dictionary += dictLength - length; /* use the tail of the dictionary */
    }
    zmemcpy(s->window, dictionary, length);
    s->strstart = length;
    s->block_start = (long)length;

    /* Insert all strings in the hash table (except for the last two bytes).
     * s->lookahead stays null, so s->ins_h will be recomputed at the next
     * call of fill_window.
     */
    s->ins_h = s->window[0];
    UPDATE_HASH(s, s->ins_h, s->window[1]);
    for (n = 0; n <= length - MIN_MATCH; n++) {
        INSERT_STRING(s, n, hash_head);
    }
    if (hash_head) hash_head = 0;  /* to make compiler happy */
    return Z_OK;
}

/* ========================================================================= */
int ZEXPORT deflateReset (strm)