Workshop o mikrokontrolérech na SKSP 2024.
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/*
* UCW Library -- Universal Sorter: Fixed-Size Internal Sorting Module
*
* (c) 2007 Martin Mares <mj@ucw.cz>
*
* This software may be freely distributed and used according to the terms
* of the GNU Lesser General Public License.
*/
#include <ucw/stkstring.h>
#define ASORT_PREFIX(x) SORT_PREFIX(array_##x)
#define ASORT_KEY_TYPE P(key)
#define ASORT_LT(x,y) (P(compare)(&(x), &(y)) < 0)
#ifdef SORT_INTERNAL_RADIX
# define ASORT_HASH(x) P(hash)(&(x))
# ifdef SORT_LONG_HASH
# define ASORT_LONG_HASH
# endif
#endif
#include <ucw/sorter/array.h>
/*
* This is a more efficient implementation of the internal sorter,
* which runs under the following assumptions:
*
* - the keys have fixed (and small) size
* - no data are present after the key
* - unification does not require any workspace
*/
static size_t P(internal_workspace)(void)
{
size_t workspace = 0;
#ifdef SORT_UNIFY
workspace = sizeof(P(key) *);
#endif
#ifdef SORT_INTERNAL_RADIX
workspace = MAX(workspace, sizeof(P(key)));
#endif
return workspace;
}
static uint P(internal_num_keys)(struct sort_context *ctx)
{
size_t bufsize = ctx->big_buf_size;
size_t workspace = P(internal_workspace)();
if (workspace)
bufsize -= CPU_PAGE_SIZE;
u64 maxkeys = bufsize / (sizeof(P(key)) + workspace);
return MIN(maxkeys, ~0U); // The number of records must fit in uint
}
static int P(internal)(struct sort_context *ctx, struct sort_bucket *bin, struct sort_bucket *bout, struct sort_bucket *bout_only)
{
sorter_alloc_buf(ctx);
struct fastbuf *in = sbuck_read(bin);
P(key) *buf = ctx->big_buf;
uint maxkeys = P(internal_num_keys)(ctx);
SORT_XTRACE(5, "s-fixint: Reading (maxkeys=%u, hash_bits=%d)", maxkeys, bin->hash_bits);
uint n = 0;
while (n < maxkeys && P(read_key)(in, &buf[n]))
n++;
if (!n)
return 0;
void *workspace UNUSED = ALIGN_PTR(&buf[n], CPU_PAGE_SIZE);
SORT_XTRACE(4, "s-fixint: Sorting %u items (%s items, %s workspace)",
n,
stk_fsize(n * sizeof(P(key))),
stk_fsize(n * P(internal_workspace)()));
timestamp_t timer;
init_timer(&timer);
buf = P(array_sort)(buf, n
#ifdef SORT_INTERNAL_RADIX
, workspace, bin->hash_bits
#endif
);
if ((void *)buf != ctx->big_buf)
workspace = ctx->big_buf;
ctx->total_int_time += get_timer(&timer);
SORT_XTRACE(5, "s-fixint: Writing");
if (n < maxkeys)
bout = bout_only;
struct fastbuf *out = sbuck_write(bout);
bout->runs++;
uint merged UNUSED = 0;
for (uint i=0; i<n; i++)
{
#ifdef SORT_UNIFY
if (i < n-1 && !P(compare)(&buf[i], &buf[i+1]))
{
P(key) **keys = workspace;
uint n = 2;
keys[0] = &buf[i];
keys[1] = &buf[i+1];
while (!P(compare)(&buf[i], &buf[i+n]))
{
keys[n] = &buf[i+n];
n++;
}
P(write_merged)(out, keys, NULL, n, NULL);
merged += n - 1;
i += n - 1;
continue;
}
#endif
#ifdef SORT_ASSERT_UNIQUE
ASSERT(i == n-1 || P(compare)(&buf[i], &buf[i+1]) < 0);
#endif
P(write_key)(out, &buf[i]);
}
#ifdef SORT_UNIFY
SORT_XTRACE(4, "Merging reduced %u records", merged);
#endif
return (n == maxkeys);
}
static u64
P(internal_estimate)(struct sort_context *ctx, struct sort_bucket *b UNUSED)
{
return P(internal_num_keys)(ctx) * sizeof(P(key)) - 1; // -1 since if the buffer is full, we don't recognize EOF
}