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/* $NetBSD: nbperf-bdz.c,v 1.9 2014/04/30 21:04:58 joerg Exp $ */
/*-
* Copyright (c) 2009, 2012 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by Joerg Sonnenberger.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#include <err.h>
#include <inttypes.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "nbperf.h"
/*
* A full description of the algorithm can be found in:
* "Simple and Space-Efficient Minimal Perfect Hash Functions"
* by Botelho, Pagh and Ziviani, proceeedings of WADS 2007.
*/
/*
* The algorithm is based on random, acyclic 3-graphs.
*
* Each edge in the represents a key. The vertices are the reminder of
* the hash function mod n. n = cm with c > 1.23. This ensures that
* an acyclic graph can be found with a very high probality.
*
* An acyclic graph has an edge order, where at least one vertex of
* each edge hasn't been seen before. It is declares the first unvisited
* vertex as authoritive for the edge and assigns a 2bit value to unvisited
* vertices, so that the sum of all vertices of the edge modulo 4 is
* the index of the authoritive vertex.
*/
#include "graph3.h"
struct state {
struct graph3 graph;
uint32_t *visited;
uint32_t *holes64k;
uint16_t *holes64;
uint8_t *g;
uint32_t *result_map;
};
static void
assign_nodes(struct state *state)
{
struct edge3 *e;
size_t i, j;
uint32_t t, r, holes;
for (i = 0; i < state->graph.v; ++i)
state->g[i] = 3;
for (i = 0; i < state->graph.e; ++i) {
j = state->graph.output_order[i];
e = &state->graph.edges[j];
if (!state->visited[e->left]) {
r = 0;
t = e->left;
} else if (!state->visited[e->middle]) {
r = 1;
t = e->middle;
} else {
if (state->visited[e->right])
abort();
r = 2;
t = e->right;
}
state->visited[t] = 2 + j;
if (state->visited[e->left] == 0)
state->visited[e->left] = 1;
if (state->visited[e->middle] == 0)
state->visited[e->middle] = 1;
if (state->visited[e->right] == 0)
state->visited[e->right] = 1;
state->g[t] = (9 + r - state->g[e->left] - state->g[e->middle]
- state->g[e->right]) % 3;
}
holes = 0;
for (i = 0; i < state->graph.v; ++i) {
if (i % 65536 == 0)
state->holes64k[i >> 16] = holes;
if (i % 64 == 0)
state->holes64[i >> 6] = holes - state->holes64k[i >> 16];
if (state->visited[i] > 1) {
j = state->visited[i] - 2;
state->result_map[j] = i - holes;
}
if (state->g[i] == 3)
++holes;
}
}
static void
print_hash(struct nbperf *nbperf, struct state *state)
{
uint64_t sum;
size_t i;
fprintf(nbperf->output, "#include <stdlib.h>\n");
fprintf(nbperf->output, "#include <strings.h>\n\n");
fprintf(nbperf->output, "%suint32_t\n",
nbperf->static_hash ? "static " : "");
fprintf(nbperf->output,
"%s(const void * __restrict key, size_t keylen)\n",
nbperf->hash_name);
fprintf(nbperf->output, "{\n");
fprintf(nbperf->output,
"\tstatic const uint64_t g1[%" PRId32 "] = {\n",
(state->graph.v + 63) / 64);
sum = 0;
for (i = 0; i < state->graph.v; ++i) {
sum |= ((uint64_t)state->g[i] & 1) << (i & 63);
if (i % 64 == 63) {
fprintf(nbperf->output, "%s0x%016" PRIx64 "ULL,%s",
(i / 64 % 2 == 0 ? "\t " : " "),
sum,
(i / 64 % 2 == 1 ? "\n" : ""));
sum = 0;
}
}
if (i % 64 != 0) {
fprintf(nbperf->output, "%s0x%016" PRIx64 "ULL,%s",
(i / 64 % 2 == 0 ? "\t " : " "),
sum,
(i / 64 % 2 == 1 ? "\n" : ""));
}
fprintf(nbperf->output, "%s\t};\n", (i % 2 ? "\n" : ""));
fprintf(nbperf->output,
"\tstatic const uint64_t g2[%" PRId32 "] = {\n",
(state->graph.v + 63) / 64);
sum = 0;
for (i = 0; i < state->graph.v; ++i) {
sum |= (((uint64_t)state->g[i] & 2) >> 1) << (i & 63);
if (i % 64 == 63) {
fprintf(nbperf->output, "%s0x%016" PRIx64 "ULL,%s",
(i / 64 % 2 == 0 ? "\t " : " "),
sum,
(i / 64 % 2 == 1 ? "\n" : ""));
sum = 0;
}
}
if (i % 64 != 0) {
fprintf(nbperf->output, "%s0x%016" PRIx64 "ULL,%s",
(i / 64 % 2 == 0 ? "\t " : " "),
sum,
(i / 64 % 2 == 1 ? "\n" : ""));
}
fprintf(nbperf->output, "%s\t};\n", (i % 2 ? "\n" : ""));
fprintf(nbperf->output,
"\tstatic const uint32_t holes64k[%" PRId32 "] = {\n",
(state->graph.v + 65535) / 65536);
for (i = 0; i < state->graph.v; i += 65536)
fprintf(nbperf->output, "%s0x%08" PRIx32 ",%s",
(i / 65536 % 4 == 0 ? "\t " : " "),
state->holes64k[i >> 16],
(i / 65536 % 4 == 3 ? "\n" : ""));
fprintf(nbperf->output, "%s\t};\n", (i / 65536 % 4 ? "\n" : ""));
fprintf(nbperf->output,
"\tstatic const uint16_t holes64[%" PRId32 "] = {\n",
(state->graph.v + 63) / 64);
for (i = 0; i < state->graph.v; i += 64)
fprintf(nbperf->output, "%s0x%04" PRIx32 ",%s",
(i / 64 % 4 == 0 ? "\t " : " "),
state->holes64[i >> 6],
(i / 64 % 4 == 3 ? "\n" : ""));
fprintf(nbperf->output, "%s\t};\n", (i / 64 % 4 ? "\n" : ""));
fprintf(nbperf->output, "\tuint64_t m;\n");
fprintf(nbperf->output, "\tuint32_t idx, i, idx2;\n");
fprintf(nbperf->output, "\tuint32_t h[%zu];\n\n", nbperf->hash_size);
(*nbperf->print_hash)(nbperf, "\t", "key", "keylen", "h");
fprintf(nbperf->output, "\n\th[0] = h[0] %% %" PRIu32 ";\n",
state->graph.v);
fprintf(nbperf->output, "\th[1] = h[1] %% %" PRIu32 ";\n",
state->graph.v);
fprintf(nbperf->output, "\th[2] = h[2] %% %" PRIu32 ";\n",
state->graph.v);
fprintf(nbperf->output,
"\tidx = 9 + ((g1[h[0] >> 6] >> (h[0] & 63)) &1)\n"
"\t + ((g1[h[1] >> 6] >> (h[1] & 63)) & 1)\n"
"\t + ((g1[h[2] >> 6] >> (h[2] & 63)) & 1)\n"
"\t - ((g2[h[0] >> 6] >> (h[0] & 63)) & 1)\n"
"\t - ((g2[h[1] >> 6] >> (h[1] & 63)) & 1)\n"
"\t - ((g2[h[2] >> 6] >> (h[2] & 63)) & 1);\n"
);
fprintf(nbperf->output,
"\tidx = h[idx %% 3];\n");
fprintf(nbperf->output,
"\tidx2 = idx - holes64[idx >> 6] - holes64k[idx >> 16];\n"
"\tidx2 -= popcount64(g1[idx >> 6] & g2[idx >> 6]\n"
"\t & (((uint64_t)1 << (idx & 63)) - 1));\n"
"\treturn idx2;\n");
fprintf(nbperf->output, "}\n");
if (nbperf->map_output != NULL) {
for (i = 0; i < state->graph.e; ++i)
fprintf(nbperf->map_output, "%" PRIu32 "\n",
state->result_map[i]);
}
}
int
bpz_compute(struct nbperf *nbperf)
{
struct state state;
int retval = -1;
uint32_t v, e;
if (nbperf->c == 0)
nbperf->c = 1.24;
if (nbperf->c < 1.24)
errx(1, "The argument for option -c must be at least 1.24");
if (nbperf->hash_size < 3)
errx(1, "The hash function must generate at least 3 values");
(*nbperf->seed_hash)(nbperf);
e = nbperf->n;
v = nbperf->c * nbperf->n;
if (1.24 * nbperf->n > v)
++v;
if (v < 10)
v = 10;
graph3_setup(&state.graph, v, e);
state.holes64k = calloc(sizeof(uint32_t), (v + 65535) / 65536);
state.holes64 = calloc(sizeof(uint16_t), (v + 63) / 64 );
state.g = calloc(sizeof(uint32_t), v | 63);
state.visited = calloc(sizeof(uint32_t), v);
state.result_map = calloc(sizeof(uint32_t), e);
if (state.holes64k == NULL || state.holes64 == NULL ||
state.g == NULL || state.visited == NULL ||
state.result_map == NULL)
err(1, "malloc failed");
if (graph3_hash(nbperf, &state.graph))
goto failed;
if (graph3_output_order(&state.graph))
goto failed;
assign_nodes(&state);
print_hash(nbperf, &state);
retval = 0;
failed:
graph3_free(&state.graph);
free(state.visited);
free(state.g);
free(state.holes64k);
free(state.holes64);
free(state.result_map);
return retval;
}