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Avoid 64-bit operations in src/hash.c; close #5201

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The idea of using `size_t` in `ea_next_capa_for` is by @dearblue.
This commit is contained in:
KOBAYASHI Shuji
2021-01-03 18:42:22 +09:00
parent c52efe7be8
commit eb9d9e3425
1 changed files with 17 additions and 7 deletions
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src/hash.c
+17 -7
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@@ -251,7 +251,6 @@ HT_ASSERT_SAFE_READ(ea_capa);
} while (0)
#define U32(v) ((uint32_t)(v))
#define U64(v) ((uint64_t)(v))
#define h_ar_p(h) (!h_ht_p(h))
#define h_ar_on(h) h_ht_off(h)
#define lesser(a, b) ((a) < (b) ? (a) : (b))
@@ -360,7 +359,13 @@ ea_next_capa_for(uint32_t size, uint32_t max_capa)
return AR_DEFAULT_CAPA;
}
else {
uint64_t capa = U64(size) * EA_INCREASE_RATIO, inc = capa - size;
/*
* For 32-bit CPU, the theoretical value of max EA capa is
* `UINT32_MAX / sizeof (hash_entry)`. At this time, if
* `EA_INCREASE_RATIO` is the current value, 32-bit range will not be
* exceeded during the calculation of `capa`, so `size_t` is used.
*/
size_t capa = size * EA_INCREASE_RATIO, inc = capa - size;
if (EA_MAX_INCREASE < inc) capa = size + EA_MAX_INCREASE;
return capa <= max_capa ? U32(capa) : max_capa;
}
@@ -621,10 +626,13 @@ ib_it_next(index_buckets_iter *it)
* \ `-- bit_pos(34)
* `-- bit(5)
*/
uint64_t bit_pos;
bit_pos = U64(it->bit) * (it->pos + 1) - 1;
it->ary_index = U32(bit_pos / IB_TYPE_BIT);
it->shift2 = U32((U64(it->ary_index) + 1) * IB_TYPE_BIT - bit_pos - 1);
/* Slide to handle as `capa == 32` to avoid 64-bit operations */
uint32_t slid_pos = it->pos & (IB_TYPE_BIT - 1);
uint32_t slid_bit_pos = it->bit * (slid_pos + 1) - 1;
uint32_t slid_ary_index = slid_bit_pos / IB_TYPE_BIT;
it->ary_index = slid_ary_index + it->pos / IB_TYPE_BIT * it->bit;
it->shift2 = (slid_ary_index + 1) * IB_TYPE_BIT - slid_bit_pos - 1;
it->ea_index = (ht_ib(it->h)[it->ary_index] >> it->shift2) & it->mask;
if (IB_TYPE_BIT - it->bit < it->shift2) {
it->shift1 = IB_TYPE_BIT - it->shift2;
@@ -707,7 +715,9 @@ ib_bit_for(uint32_t size)
static uint32_t
ib_byte_size_for(uint32_t ib_bit)
{
uint64_t ary_size = (U64(1) << ib_bit) * ib_bit / IB_TYPE_BIT;
uint32_t ary_size = IB_INIT_BIT == 4 ?
ib_bit_to_capa(ib_bit) * 2 / IB_TYPE_BIT * ib_bit / 2 :
ib_bit_to_capa(ib_bit) / IB_TYPE_BIT * ib_bit;
return U32(sizeof(uint32_t) * ary_size);
}