local int gz_comp()

in zlib/gzwrite.c [65:139]

• 58 lines of code
• 20 McCabe index (conditional complexity)

local int gz_comp(gz_statep state, int flush) {
    int ret, writ;
    unsigned have, put, max = ((unsigned)-1 >> 2) + 1;
    z_streamp strm = &(state->strm);

    /* allocate memory if this is the first time through */
    if (state->size == 0 && gz_init(state) == -1)
        return -1;

    /* write directly if requested */
    if (state->direct) {
        while (strm->avail_in) {
            put = strm->avail_in > max ? max : strm->avail_in;
            writ = write(state->fd, strm->next_in, put);
            if (writ < 0) {
                gz_error(state, Z_ERRNO, zstrerror());
                return -1;
            }
            strm->avail_in -= (unsigned)writ;
            strm->next_in += writ;
        }
        return 0;
    }

    /* check for a pending reset */
    if (state->reset) {
        /* don't start a new gzip member unless there is data to write */
        if (strm->avail_in == 0)
            return 0;
        deflateReset(strm);
        state->reset = 0;
    }

    /* run deflate() on provided input until it produces no more output */
    ret = Z_OK;
    do {
        /* write out current buffer contents if full, or if flushing, but if
           doing Z_FINISH then don't write until we get to Z_STREAM_END */
        if (strm->avail_out == 0 || (flush != Z_NO_FLUSH &&
            (flush != Z_FINISH || ret == Z_STREAM_END))) {
            while (strm->next_out > state->x.next) {
                put = strm->next_out - state->x.next > (int)max ? max :
                      (unsigned)(strm->next_out - state->x.next);
                writ = write(state->fd, state->x.next, put);
                if (writ < 0) {
                    gz_error(state, Z_ERRNO, zstrerror());
                    return -1;
                }
                state->x.next += writ;
            }
            if (strm->avail_out == 0) {
                strm->avail_out = state->size;
                strm->next_out = state->out;
                state->x.next = state->out;
            }
        }

        /* compress */
        have = strm->avail_out;
        ret = deflate(strm, flush);
        if (ret == Z_STREAM_ERROR) {
            gz_error(state, Z_STREAM_ERROR,
                      "internal error: deflate stream corrupt");
            return -1;
        }
        have -= strm->avail_out;
    } while (have);

    /* if that completed a deflate stream, allow another to start */
    if (flush == Z_FINISH)
        state->reset = 1;

    /* all done, no errors */
    return 0;
}