Mercurial > hg > cdb
annotate cdb_hash.c @ 12:0e21568dec72
allocate a Cdb struct rather than using a single static one,
note that cdb_free does _not_ call alloc_free, just releases the map,
in fact alloc_free is not called anywhere!
| author | Henry S. Thompson <ht@inf.ed.ac.uk> |
|---|---|
| date | Mon, 03 Feb 2025 17:31:23 +0000 |
| parents | 2cb46628feec |
| children |
| rev | line source |
|---|---|
|
0
2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
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1 /* Public domain. */ |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
2 |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
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3 #include "cdb.h" |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
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4 |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
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5 uint32 cdb_hashadd(uint32 h,unsigned char c) |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
6 { |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
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7 h += (h << 5); |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
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8 return h ^ c; |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
9 } |
|
2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
10 |
|
2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
11 uint32 cdb_hash(char *buf,unsigned int len) |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
12 { |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
13 uint32 h; |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
14 |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
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15 h = CDB_HASHSTART; |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
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16 while (len) { |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
17 h = cdb_hashadd(h,*buf++); |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
18 --len; |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
19 } |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
20 return h; |
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2cb46628feec
from cdb-0.75 per http://cr.yp.to/cdb.html,
Henry S. Thompson <ht@inf.ed.ac.uk>
parents:
diff
changeset
|
21 } |
