On Sat, Sep 21, 2002 at 11:40:41PM -0000, [EMAIL PROTECTED] wrote:
>...
> +{
> + apr_bucket *e = APR_BRIGADE_LAST(b);
> + apr_size_t remaining;
> + char *buf;
> + apr_size_t bytes_written = 0;
> + apr_size_t i;
> +
> + /* Step 1: check if there is a heap bucket at the end
> + * of the brigade already
> + */
> + if (!APR_BRIGADE_EMPTY(b) && APR_BUCKET_IS_HEAP(e)) {
> + apr_bucket_heap *h = e->data;
> + remaining = h->alloc_len - (e->length + (apr_size_t)e->start);
> + buf = h->base + e->start + e->length;
> + }
> + else {
> + remaining = 0;
> + buf = NULL;
> + }
> +
> + /* Step 2: copy the data into the heap bucket, appending
> + * a new heap bucket each time the old one becomes full
> + */
> + for (i = 0; i < nvec; i++) {
> + apr_size_t nbyte = vec[i].iov_len;
> + const char *str = (const char *)(vec[i].iov_base);
> +
> + bytes_written += nbyte;
> + if (nbyte <= remaining) {
> + memcpy(buf, str, nbyte);
> + e->length += nbyte;
> + buf += nbyte;
> + remaining -= nbyte;
> + }
> + else if (nbyte < APR_BUCKET_BUFF_SIZE) {
> + buf = apr_bucket_alloc(APR_BUCKET_BUFF_SIZE, b->bucket_alloc);
> + e = apr_bucket_heap_create(buf, APR_BUCKET_BUFF_SIZE,
> + apr_bucket_free, b->bucket_alloc);
> + APR_BRIGADE_INSERT_TAIL(b, e);
> + memcpy(buf, str, nbyte);
> + e->length = nbyte;
> + buf += nbyte;
> + remaining = APR_BUCKET_BUFF_SIZE - nbyte;
> + }
> + else { /* String larger than APR_BUCKET_BUFF_SIZE */
> + e = apr_bucket_transient_create(str, nbyte, b->bucket_alloc);
> + APR_BRIGADE_INSERT_TAIL(b, e);
> + remaining = 0; /* create a new heap bucket for the next write
> */
> + }
Ewww... icky implementation... If you have a dozen iovec's where each
iov_len is slightly less than APR_BUCKET_BUFF_SIZE, then you're going to
copy the entire thing onto the heap.
> + /* Step 3: if necessary, output the brigade contents now
> + */
> + if (bytes_written >= APR_BUCKET_BUFF_SIZE) {
> + return flush(b, ctx);
> + }
And *then* you're going to flush the thing.
If you total up the number of bytes represented by the iovec, and that total
is more than APR_BUCKET_BUFF_SIZE, then simply create <nvec> TRANSIENT
buckets and flush the thing. No copies at all.
If the total is less, then go ahead and shove the iovec's onto the existing
HEAP bucket, and/or one or two new HEAP buckets (you can show that you'll
never need more than two (existing/created) buckets altogether).
I also think that doing it this way will also greatly simplify the code.
Cheers,
-g
--
Greg Stein, http://www.lyra.org/
