File: isl_hash.c

package info (click to toggle)
isl 0.20-2
  • links: PTS
  • area: main
  • in suites: buster, sid
  • size: 12,708 kB
  • sloc: ansic: 125,702; python: 5,770; sh: 4,291; cpp: 1,057; makefile: 497; lisp: 54; perl: 9
file content (235 lines) | stat: -rw-r--r-- 5,056 bytes parent folder | download | duplicates (22)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
/*
 * Copyright 2008-2009 Katholieke Universiteit Leuven
 *
 * Use of this software is governed by the MIT license
 *
 * Written by Sven Verdoolaege, K.U.Leuven, Departement
 * Computerwetenschappen, Celestijnenlaan 200A, B-3001 Leuven, Belgium
 */

#include <stdlib.h>
#include <isl_hash_private.h>
#include <isl/ctx.h>
#include "isl_config.h"

uint32_t isl_hash_string(uint32_t hash, const char *s)
{
	for (; *s; s++)
		isl_hash_byte(hash, *s);
	return hash;
}

uint32_t isl_hash_mem(uint32_t hash, const void *p, size_t len)
{
	int i;
	const char *s = p;
	for (i = 0; i < len; ++i)
		isl_hash_byte(hash, s[i]);
	return hash;
}

static unsigned int round_up(unsigned int v)
{
	int old_v = v;

	while (v) {
		old_v = v;
		v ^= v & -v;
	}
	return old_v << 1;
}

int isl_hash_table_init(struct isl_ctx *ctx, struct isl_hash_table *table,
			int min_size)
{
	size_t size;

	if (!table)
		return -1;

	if (min_size < 2)
		min_size = 2;
	table->bits = ffs(round_up(4 * (min_size + 1) / 3 - 1)) - 1;
	table->n = 0;

	size = 1 << table->bits;
	table->entries = isl_calloc_array(ctx, struct isl_hash_table_entry,
					  size);
	if (!table->entries)
		return -1;

	return 0;
}

/* Dummy comparison function that always returns false.
 */
static int no(const void *entry, const void *val)
{
	return 0;
}

/* Extend "table" to twice its size.
 * Return 0 on success and -1 on error.
 *
 * We reuse isl_hash_table_find to create entries in the extended table.
 * Since all entries in the original table are assumed to be different,
 * there is no need to compare them against each other.
 */
static int grow_table(struct isl_ctx *ctx, struct isl_hash_table *table)
{
	int n;
	size_t old_size, size;
	struct isl_hash_table_entry *entries;
	uint32_t h;

	entries = table->entries;
	old_size = 1 << table->bits;
	size = 2 * old_size;
	table->entries = isl_calloc_array(ctx, struct isl_hash_table_entry,
					  size);
	if (!table->entries) {
		table->entries = entries;
		return -1;
	}

	n = table->n;
	table->n = 0;
	table->bits++;

	for (h = 0; h < old_size; ++h) {
		struct isl_hash_table_entry *entry;

		if (!entries[h].data)
			continue;

		entry = isl_hash_table_find(ctx, table, entries[h].hash,
					    &no, NULL, 1);
		if (!entry) {
			table->bits--;
			free(table->entries);
			table->entries = entries;
			table->n = n;
			return -1;
		}

		*entry = entries[h];
	}

	free(entries);

	return 0;
}

struct isl_hash_table *isl_hash_table_alloc(struct isl_ctx *ctx, int min_size)
{
	struct isl_hash_table *table = NULL;

	table = isl_alloc_type(ctx, struct isl_hash_table);
	if (isl_hash_table_init(ctx, table, min_size))
		goto error;
	return table;
error:
	isl_hash_table_free(ctx, table);
	return NULL;
}

void isl_hash_table_clear(struct isl_hash_table *table)
{
	if (!table)
		return;
	free(table->entries);
}

void isl_hash_table_free(struct isl_ctx *ctx, struct isl_hash_table *table)
{
	if (!table)
		return;
	isl_hash_table_clear(table);
	free(table);
}

/* A dummy entry that can be used to make a distinction between
 * a missing entry and an error condition.
 * It is used by isl_union_*_find_part_entry.
 */
static struct isl_hash_table_entry none = { 0, NULL };
struct isl_hash_table_entry *isl_hash_table_entry_none = &none;

struct isl_hash_table_entry *isl_hash_table_find(struct isl_ctx *ctx,
				struct isl_hash_table *table,
				uint32_t key_hash,
				int (*eq)(const void *entry, const void *val),
				const void *val, int reserve)
{
	size_t size;
	uint32_t h, key_bits;

	key_bits = isl_hash_bits(key_hash, table->bits);
	size = 1 << table->bits;
	for (h = key_bits; table->entries[h].data; h = (h+1) % size)
		if (table->entries[h].hash == key_hash &&
		    eq(table->entries[h].data, val))
			return &table->entries[h];

	if (!reserve)
		return NULL;

	if (4 * table->n >= 3 * size) {
		if (grow_table(ctx, table) < 0)
			return NULL;
		return isl_hash_table_find(ctx, table, key_hash, eq, val, 1);
	}

	table->n++;
	table->entries[h].hash = key_hash;

	return &table->entries[h];
}

isl_stat isl_hash_table_foreach(isl_ctx *ctx, struct isl_hash_table *table,
	isl_stat (*fn)(void **entry, void *user), void *user)
{
	size_t size;
	uint32_t h;

	if (!table->entries)
		return isl_stat_error;

	size = 1 << table->bits;
	for (h = 0; h < size; ++ h)
		if (table->entries[h].data &&
		    fn(&table->entries[h].data, user) < 0)
			return isl_stat_error;
	
	return isl_stat_ok;
}

void isl_hash_table_remove(struct isl_ctx *ctx,
				struct isl_hash_table *table,
				struct isl_hash_table_entry *entry)
{
	int h, h2;
	size_t size;

	if (!table || !entry)
		return;

	size = 1 << table->bits;
	h = entry - table->entries;
	isl_assert(ctx, h >= 0 && h < size, return);

	for (h2 = h+1; table->entries[h2 % size].data; h2++) {
		uint32_t bits = isl_hash_bits(table->entries[h2 % size].hash,
						table->bits);
		uint32_t offset = (size + bits - (h+1)) % size;
		if (offset <= h2 - (h+1))
			continue;
		*entry = table->entries[h2 % size];
		h = h2;
		entry = &table->entries[h % size];
	}

	entry->hash = 0;
	entry->data = NULL;
	table->n--;
}