int db_file_mread(struct db_file *f, void **data, const uint32_t len,
const uint32_t pos)
{
ssize_t n;
if (pos + len > f->len)
return -1;
if (!cached(f, len, pos)) {
if (grow_cache(f, len))
return -1;
#ifdef HAVE_PREAD
n = pread(f->fd, f->cache, len, pos);
#else
if (pos != f->pos && lseek(f->fd, pos, SEEK_SET) != pos)
return -1;
n = read(f->fd, f->cache, len);
#endif
if (n >= 0)
f->pos = pos + n;
if (n != len) return -1;
f->cache_pos = pos;
f->cache_len = len;
}
*data = (char *)f->cache + (pos - f->cache_pos);
return 0;
}
int db_file_write(struct db_file *f, void *data, uint32_t len)
{
ssize_t n;
uint32_t blob;
if (!len) return 0;
if (grow_cache(f, PAGESIZE))
return -1;
/* first fill the rest of the page */
blob = len < (PAGESIZE - f->pending) ? len : PAGESIZE - f->pending;
memcpy((char *)f->cache + f->pending, data, blob);
f->pending += blob;
data = (char *)data + blob;
len -= blob;
f->pos += blob;
/* flush full pages */
if (f->pending == PAGESIZE) {
n = write(f->fd, f->cache, PAGESIZE);
if (n == -1) return -1;
f->pending = 0;
}
/* flush rest of the data, when it is a lot */
blob = len & ~(PAGESIZE - 1);
if (blob) {
n = write(f->fd, data, blob);
if (n == -1) return -1;
data = (char *)data + blob;
len -= blob;
f->pos += blob;
}
/* start filling the next page with the leftovers */
if (len) {
memcpy(f->cache, data, len);
f->pending += len;
f->pos += len;
}
if (f->pos > f->len)
f->len = f->pos;
return 0;
}
void
build_cache()
{
if (cached_ng == ng && cached_absfirst == absfirst
&& time((time_t*)NULL) < cached_time + 6*60*60L) {
grow_cache(lastart);
rc_to_bits();
if (sel_mode == SM_ARTICLE)
set_selector(sel_mode, sel_artsort);
else
set_selector(sel_threadmode, sel_threadsort);
thread_grow();
return;
}
close_cache();
cached_ng = ng;
cached_absfirst = absfirst;
cached_time = time((time_t*)NULL);
cached_cnt = lastart-absfirst+2 + 5;
article_list = (ARTICLE*)
safemalloc((MEM_SIZE)(cached_cnt * sizeof (ARTICLE)));
bzero((char*)article_list, cached_cnt * sizeof (ARTICLE));
subj_hash = hashcreate(201, subject_cmp); /*TODO: pick a better size */
rc_to_bits(); /* sets firstart */
first_cached = thread_always? absfirst : firstart;
last_cached = first_cached-1;
cached_all_in_range = FALSE;
#ifdef PENDING
subj_to_get = xref_to_get = firstart;
#endif
#ifndef USE_NNTP
setmissingbits();
#endif
/* Cache as much data in advance as possible, possibly threading
** articles as we go. */
thread_open();
}
