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[map] Move prime_mod to header to avoid linkage issues in subset.so

This commit is contained in:
Behdad Esfahbod 2018-05-29 18:13:13 -07:00
parent 6baebc5d55
commit ccd01c6555
2 changed files with 51 additions and 54 deletions
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53
src/hb-map-private.hh
View File

@ -182,9 +182,58 @@ struct hb_map_t
}
protected:
static HB_INTERNAL unsigned int prime_for (unsigned int shift);
unsigned int bucket_for (hb_codepoint_t key) const
static inline unsigned int prime_for (unsigned int shift)
{
/* Following comment and table copied from glib. */
/* Each table size has an associated prime modulo (the first prime
* lower than the table size) used to find the initial bucket. Probing
* then works modulo 2^n. The prime modulo is necessary to get a
* good distribution with poor hash functions.
*/
static const unsigned int prime_mod [] =
{
1, /* For 1 << 0 */
2,
3,
7,
13,
31,
61,
127,
251,
509,
1021,
2039,
4093,
8191,
16381,
32749,
65521, /* For 1 << 16 */
131071,
262139,
524287,
1048573,
2097143,
4194301,
8388593,
16777213,
33554393,
67108859,
134217689,
268435399,
536870909,
1073741789,
2147483647 /* For 1 << 31 */
};
if (unlikely (shift >= ARRAY_LENGTH (prime_mod)))
return prime_mod[ARRAY_LENGTH (prime_mod) -1];
return prime_mod[shift];
}
inline unsigned int bucket_for (hb_codepoint_t key) const
{
unsigned int i = Hash (key) % prime;
unsigned int step = 0;

52
src/hb-map.cc
View File

@ -269,55 +269,3 @@ hb_map_get_population (const hb_map_t *map)
{
return map->get_population ();
}
/* Following comment and table copied from glib. */
/* Each table size has an associated prime modulo (the first prime
* lower than the table size) used to find the initial bucket. Probing
* then works modulo 2^n. The prime modulo is necessary to get a
* good distribution with poor hash functions.
*/
static const unsigned int prime_mod [] =
{
1, /* For 1 << 0 */
2,
3,
7,
13,
31,
61,
127,
251,
509,
1021,
2039,
4093,
8191,
16381,
32749,
65521, /* For 1 << 16 */
131071,
262139,
524287,
1048573,
2097143,
4194301,
8388593,
16777213,
33554393,
67108859,
134217689,
268435399,
536870909,
1073741789,
2147483647 /* For 1 << 31 */
};
unsigned int
hb_map_t::prime_for (unsigned int shift)
{
if (unlikely (shift >= ARRAY_LENGTH (prime_mod)))
return prime_mod[ARRAY_LENGTH (prime_mod) -1];
return prime_mod[shift];
}