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string.c (mrb_byte_hash): separate byte hashing functions.

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This commit is contained in:
Yukihiro "Matz" Matsumoto
2022-08-05 09:10:02 +09:00
parent 62a35e502b
commit 61f447e5df
1 changed files with 18 additions and 8 deletions
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src/string.c
+18 -8
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@@ -1665,22 +1665,19 @@ mrb_str_substr(mrb_state *mrb, mrb_value str, mrb_int beg, mrb_int len)
/*
* 32 bit magic FNV-0 and FNV-1 prime
*/
b */
#define FNV_32_PRIME ((uint32_t)0x01000193)
#define FNV1_32_INIT ((uint32_t)0x811c9dc5)
uint32_t
mrb_str_hash(mrb_state *mrb, mrb_value str)
mrb_byte_hash_step(const uint8_t *s, mrb_int len, uint32_t hval)
{
struct RString *s = mrb_str_ptr(str);
const unsigned char *bp = (unsigned char*)RSTR_PTR(s); /* start of buffer */
const unsigned char *be = bp + RSTR_LEN(s); /* beyond end of buffer */
uint32_t hval = FNV1_32_INIT;
const uint8_t *send = s + len;
/*
* FNV-1 hash each octet in the buffer
*/
while (bp < be) {
while (s < send) {
/* multiply by the 32 bit FNV magic prime mod 2^32 */
#if defined(NO_FNV_GCC_OPTIMIZATION)
hval *= FNV_32_PRIME;
@@ -1689,13 +1686,26 @@ mrb_str_hash(mrb_state *mrb, mrb_value str)
#endif
/* xor the bottom with the current octet */
hval ^= (uint32_t)*bp++;
hval ^= (uint32_t)*s++;
}
/* return our new hash value */
return hval;
}
uint32_t
mrb_byte_hash(const uint8_t *s, mrb_int len)
{
return mrb_byte_hash_step(s, len, FNV1_32_INIT);
}
uint32_t
mrb_str_hash(mrb_state *mrb, mrb_value str)
{
struct RString *s = mrb_str_ptr(str);
return mrb_byte_hash((uint8_t*)RSTR_PTR(s), RSTR_LEN(s));
}
/* 15.2.10.5.20 */
/*
* call-seq: