int ZEXPORTVA gzvprintf()

in zlib/gzwrite.c [359:428]

• 54 lines of code
• 16 McCabe index (conditional complexity)

int ZEXPORTVA gzvprintf(gzFile file, const char *format, va_list va) {
    int len;
    unsigned left;
    char *next;
    gz_statep state;
    z_streamp strm;

    /* get internal structure */
    if (file == NULL)
        return Z_STREAM_ERROR;
    state = (gz_statep)file;
    strm = &(state->strm);

    /* check that we're writing and that there's no error */
    if (state->mode != GZ_WRITE || state->err != Z_OK)
        return Z_STREAM_ERROR;

    /* make sure we have some buffer space */
    if (state->size == 0 && gz_init(state) == -1)
        return state->err;

    /* check for seek request */
    if (state->seek) {
        state->seek = 0;
        if (gz_zero(state, state->skip) == -1)
            return state->err;
    }

    /* do the printf() into the input buffer, put length in len -- the input
       buffer is double-sized just for this function, so there is guaranteed to
       be state->size bytes available after the current contents */
    if (strm->avail_in == 0)
        strm->next_in = state->in;
    next = (char *)(state->in + (strm->next_in - state->in) + strm->avail_in);
    next[state->size - 1] = 0;
#ifdef NO_vsnprintf
#  ifdef HAS_vsprintf_void
    (void)vsprintf(next, format, va);
    for (len = 0; len < state->size; len++)
        if (next[len] == 0) break;
#  else
    len = vsprintf(next, format, va);
#  endif
#else
#  ifdef HAS_vsnprintf_void
    (void)vsnprintf(next, state->size, format, va);
    len = strlen(next);
#  else
    len = vsnprintf(next, state->size, format, va);
#  endif
#endif

    /* check that printf() results fit in buffer */
    if (len == 0 || (unsigned)len >= state->size || next[state->size - 1] != 0)
        return 0;

    /* update buffer and position, compress first half if past that */
    strm->avail_in += (unsigned)len;
    state->x.pos += len;
    if (strm->avail_in >= state->size) {
        left = strm->avail_in - state->size;
        strm->avail_in = state->size;
        if (gz_comp(state, Z_NO_FLUSH) == -1)
            return state->err;
        memmove(state->in, state->in + state->size, left);
        strm->next_in = state->in;
        strm->avail_in = left;
    }
    return len;
}