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khash: clarify that allocations never fail 

We use our standard allocation functions and macros (xcalloc,
ALLOC_ARRAY, REALLOC_ARRAY) in our version of khash.h.  They terminate
the program on error instead, so code that's using them doesn't have to
handle allocation failures.  Make this behavior explicit by turning
kh_resize_ into a void function and removing the related unreachable
error handling code.

Helped-by: Jeff King <peff@peff.net>
Signed-off-by: René Scharfe <l.s.r@web.de>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
René Scharfe 2021-07-03 14:57:30 +02:00 committed by Junio C Hamano
parent ebf3c04b26
commit 5632e838f8
1 changed files with 5 additions and 9 deletions
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14
khash.h
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@ -74,7 +74,7 @@ static const double __ac_HASH_UPPER = 0.77;
void kh_destroy_##name(kh_##name##_t *h); \
void kh_clear_##name(kh_##name##_t *h); \
khint_t kh_get_##name(const kh_##name##_t *h, khkey_t key); \
int kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets); \
void kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets); \
khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret); \
void kh_del_##name(kh_##name##_t *h, khint_t x);
@ -116,7 +116,7 @@ static const double __ac_HASH_UPPER = 0.77;
return __ac_iseither(h->flags, i)? h->n_buckets : i; \
} else return 0; \
} \
SCOPE int kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets) \
SCOPE void kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets) \
{ /* This function uses 0.25*n_buckets bytes of working space instead of [sizeof(key_t+val_t)+.25]*n_buckets. */ \
khint32_t *new_flags = NULL; \
khint_t j = 1; \
@ -126,7 +126,6 @@ static const double __ac_HASH_UPPER = 0.77;
if (h->size >= (khint_t)(new_n_buckets * __ac_HASH_UPPER + 0.5)) j = 0; /* requested size is too small */ \
else { /* hash table size to be changed (shrink or expand); rehash */ \
ALLOC_ARRAY(new_flags, __ac_fsize(new_n_buckets)); \
if (!new_flags) return -1; \
memset(new_flags, 0xaa, __ac_fsize(new_n_buckets) * sizeof(khint32_t)); \
if (h->n_buckets < new_n_buckets) { /* expand */ \
REALLOC_ARRAY(h->keys, new_n_buckets); \
@ -173,18 +172,15 @@ static const double __ac_HASH_UPPER = 0.77;
h->n_occupied = h->size; \
h->upper_bound = (khint_t)(h->n_buckets * __ac_HASH_UPPER + 0.5); \
} \
return 0; \
} \
SCOPE khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret) \
{ \
khint_t x; \
if (h->n_occupied >= h->upper_bound) { /* update the hash table */ \
if (h->n_buckets > (h->size<<1)) { \
if (kh_resize_##name(h, h->n_buckets - 1) < 0) { /* clear "deleted" elements */ \
*ret = -1; return h->n_buckets; \
} \
} else if (kh_resize_##name(h, h->n_buckets + 1) < 0) { /* expand the hash table */ \
*ret = -1; return h->n_buckets; \
kh_resize_##name(h, h->n_buckets - 1); /* clear "deleted" elements */ \
} else { \
kh_resize_##name(h, h->n_buckets + 1); /* expand the hash table */ \
} \
} /* TODO: to implement automatically shrinking; resize() already support shrinking */ \
{ \