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Overview
| Comment: | Use Knuth multiplicative hashing for the symbol table. |
|---|---|
| Downloads: | Tarball | ZIP archive | SQL archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
cc29ddd6be60bdbf107f285c9eb57d58 |
| User & Date: | drh 2016-09-28 20:42:31 |
Context
|
2016-09-29
| ||
| 15:53 | Clarification and typo-fixes in comments. No changes to code. check-in: e2cd79aa user: drh tags: trunk | |
|
2016-09-28
| ||
| 20:42 | Use Knuth multiplicative hashing for the symbol table. check-in: cc29ddd6 user: drh tags: trunk | |
| 16:05 | Two more typo fixes in comments. check-in: 40c0fb0a user: drh tags: trunk | |
Changes
Changes to src/hash.c.
52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 |
/*
** The hashing function.
*/
static unsigned int strHash(const char *z){
unsigned int h = 0;
unsigned char c;
while( (c = (unsigned char)*z++)!=0 ){ /*OPTIMIZATION-IF-TRUE*/
h = (h<<3) ^ h ^ sqlite3UpperToLower[c];
}
return h;
}
/* Link pNew element into the hash table pH. If pEntry!=0 then also
** insert pNew into the pEntry hash bucket.
|
> > > | > |
52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 |
/*
** The hashing function.
*/
static unsigned int strHash(const char *z){
unsigned int h = 0;
unsigned char c;
while( (c = (unsigned char)*z++)!=0 ){ /*OPTIMIZATION-IF-TRUE*/
/* Knuth multiplicative hashing. (Sorting & Searching, p. 510).
** 0x9e3779b1 is 2654435761 which is the closest prime number to
** (2**32)*golden_ratio, where golden_ratio = (sqrt(5) - 1)/2. */
h += sqlite3UpperToLower[c];
h *= 0x9e3779b1;
}
return h;
}
/* Link pNew element into the hash table pH. If pEntry!=0 then also
** insert pNew into the pEntry hash bucket.
|