2 * UCW Library -- Universal Sorter: Fixed-Size Internal Sorting Module
4 * (c) 2007 Martin Mares <mj@ucw.cz>
6 * This software may be freely distributed and used according to the terms
7 * of the GNU Lesser General Public License.
10 #include "lib/stkstring.h"
12 #define ASORT_PREFIX(x) SORT_PREFIX(array_##x)
13 #define ASORT_KEY_TYPE P(key)
14 #define ASORT_LT(x,y) (P(compare)(&(x), &(y)) < 0)
15 #define ASORT_PAGE_ALIGNED
16 #include "lib/sorter/array.h"
19 * This is a more efficient implementation of the internal sorter,
20 * which runs under the following assumptions:
22 * - the keys have fixed (and small) size
23 * - no data are present after the key
24 * - unification does not require any workspace
27 static size_t P(internal_workspace)(void)
31 workspace = sizeof(P(key) *);
33 #ifdef SORT_HASH_BITS // FIXME: Another switch?
34 workspace = MAX(workspace, sizeof(P(key)));
39 static uns P(internal_num_keys)(struct sort_context *ctx)
41 size_t bufsize = ctx->big_buf_size;
42 size_t workspace = P(internal_workspace)();
44 bufsize -= CPU_PAGE_SIZE;
45 u64 maxkeys = bufsize / (sizeof(P(key)) + workspace);
46 return MIN(maxkeys, ~0U); // The number of records must fit in uns
49 static int P(internal)(struct sort_context *ctx, struct sort_bucket *bin, struct sort_bucket *bout, struct sort_bucket *bout_only)
51 sorter_alloc_buf(ctx);
52 struct fastbuf *in = sbuck_read(bin);
53 P(key) *buf = ctx->big_buf;
54 uns maxkeys = P(internal_num_keys)(ctx);
56 SORT_XTRACE(4, "s-fixint: Reading (maxkeys=%u, hash_bits=%d)", maxkeys, bin->hash_bits);
58 while (n < maxkeys && P(read_key)(in, &buf[n]))
62 void *workspace UNUSED = ALIGN_PTR(&buf[n], CPU_PAGE_SIZE);
64 SORT_XTRACE(3, "s-fixint: Sorting %u items (%s items, %s workspace)",
66 stk_fsize(n * sizeof(P(key))),
67 stk_fsize(n * P(internal_workspace)()));
70 buf = P(array_sort)(buf, n,
72 workspace, bin->hash_bits
77 ctx->total_int_time += get_timer(&timer);
79 SORT_XTRACE(4, "s-fixint: Writing");
82 struct fastbuf *out = sbuck_write(bout);
84 uns merged UNUSED = 0;
85 for (uns i=0; i<n; i++)
88 if (i < n-1 && !P(compare)(&buf[i], &buf[i+1]))
90 P(key) **keys = workspace;
94 while (!P(compare)(&buf[i], &buf[i+n]))
99 P(write_merged)(out, keys, NULL, n, NULL);
105 #ifdef SORT_ASSERT_UNIQUE
106 ASSERT(i == n-1 || P(compare)(&buf[i], &buf[i+1]) < 0);
108 P(write_key)(out, &buf[i]);
111 SORT_XTRACE(3, "Merging reduced %d records", merged);
114 return (n == maxkeys);
118 P(internal_estimate)(struct sort_context *ctx, struct sort_bucket *b UNUSED)
120 return P(internal_num_keys)(ctx) * sizeof(P(key)) - 1; // -1 since if the buffer is full, we don't recognize EOF