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Commita91e2fa

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Adapt hashfn.c and hashutils.h for frontend use.
hash_any() and its various variants are defined to return Datum,which is a backend-only concept, but the underlying functionsactually want to return uint32 and uint64, and only return Datumbecause it's convenient for callers who are using them toimplement a hash function for some SQL datatype.However, changing these functions to return uint32 and uint64seems like it might lead to programming errors or back-patchingdifficulties, both because they are widely used and becausefailure to use UInt{32,64}GetDatum() might not provoke acompilation error. Instead, rename the existing functions aswell as changing the return type, and add static inline wrappersfor those callers that need the previous behavior.Although this commit adapts hashutils.h and hashfn.c so that theycan be compiled as frontend code, it does not actually doanything that would cause them to be so compiled. That is leftfor another commit.Patch by me, reviewed by Suraj Kharage and Mark Dilger.Discussion:http://postgr.es/m/CA+TgmoaRiG4TXND8QuM6JXFRkM_1wL2ZNhzaUKsuec9-4yrkgw@mail.gmail.com
1 parent9341c78 commita91e2fa

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2 files changed

+55
-33
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2 files changed

+55
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lines changed

‎src/backend/utils/hash/hashfn.c

Lines changed: 24 additions & 28 deletions
Original file line numberDiff line numberDiff line change
@@ -16,15 +16,14 @@
1616
* It is expected that every bit of a hash function's 32-bit result is
1717
* as random as every other; failure to ensure this is likely to lead
1818
* to poor performance of hash tables. In most cases a hash
19-
* function should use hash_any() or its variant hash_uint32().
19+
* function should use hash_bytes() or its variant hash_bytes_uint32(),
20+
* or the wrappers hash_any() and hash_uint32 defined in hashfn.h.
2021
*
2122
*-------------------------------------------------------------------------
2223
*/
2324
#include"postgres.h"
2425

25-
#include"fmgr.h"
2626
#include"utils/hashutils.h"
27-
#include"utils/hsearch.h"
2827

2928

3029
/*
@@ -126,7 +125,7 @@
126125
}
127126

128127
/*
129-
*hash_any() -- hash a variable-length key into a 32-bit value
128+
*hash_bytes() -- hash a variable-length key into a 32-bit value
130129
*k: the key (the unaligned variable-length array of bytes)
131130
*len: the length of the key, counting by bytes
132131
*
@@ -143,8 +142,8 @@
143142
* by using the final values of both b and c. b is perhaps a little less
144143
* well mixed than c, however.
145144
*/
146-
Datum
147-
hash_any(constunsignedchar*k,intkeylen)
145+
uint32
146+
hash_bytes(constunsignedchar*k,intkeylen)
148147
{
149148
uint32a,
150149
b,
@@ -358,20 +357,19 @@ hash_any(const unsigned char *k, int keylen)
358357
final(a,b,c);
359358

360359
/* report the result */
361-
returnUInt32GetDatum(c);
360+
returnc;
362361
}
363362

364363
/*
365-
*hash_any_extended() -- hash into a 64-bit value, using an optional seed
364+
*hash_bytes_extended() -- hash into a 64-bit value, using an optional seed
366365
*k: the key (the unaligned variable-length array of bytes)
367366
*len: the length of the key, counting by bytes
368367
*seed: a 64-bit seed (0 means no seed)
369368
*
370-
* Returns a uint64 value. Otherwise similar tohash_any.
369+
* Returns a uint64 value. Otherwise similar tohash_bytes.
371370
*/
372-
Datum
373-
hash_any_extended(constunsignedchar*k,intkeylen,
374-
uint64seed)
371+
uint64
372+
hash_bytes_extended(constunsignedchar*k,intkeylen,uint64seed)
375373
{
376374
uint32a,
377375
b,
@@ -598,18 +596,18 @@ hash_any_extended(const unsigned char *k, int keylen,
598596
final(a,b,c);
599597

600598
/* report the result */
601-
PG_RETURN_UINT64(((uint64)b <<32) |c);
599+
return ((uint64)b <<32) |c;
602600
}
603601

604602
/*
605-
*hash_uint32() -- hash a 32-bit value to a 32-bit value
603+
*hash_bytes_uint32() -- hash a 32-bit value to a 32-bit value
606604
*
607605
* This has the same result as
608-
*hash_any(&k, sizeof(uint32))
606+
*hash_bytes(&k, sizeof(uint32))
609607
* but is faster and doesn't force the caller to store k into memory.
610608
*/
611-
Datum
612-
hash_uint32(uint32k)
609+
uint32
610+
hash_bytes_uint32(uint32k)
613611
{
614612
uint32a,
615613
b,
@@ -621,16 +619,16 @@ hash_uint32(uint32 k)
621619
final(a,b,c);
622620

623621
/* report the result */
624-
returnUInt32GetDatum(c);
622+
returnc;
625623
}
626624

627625
/*
628-
*hash_uint32_extended() -- hasha32-bit value toa64-bit value, with a seed
626+
*hash_bytes_uint32_extended() -- hash 32-bit value to 64-bit value, with seed
629627
*
630-
* Likehash_uint32, this is a convenience function.
628+
* Likehash_bytes_uint32, this is a convenience function.
631629
*/
632-
Datum
633-
hash_uint32_extended(uint32k,uint64seed)
630+
uint64
631+
hash_bytes_uint32_extended(uint32k,uint64seed)
634632
{
635633
uint32a,
636634
b,
@@ -650,7 +648,7 @@ hash_uint32_extended(uint32 k, uint64 seed)
650648
final(a,b,c);
651649

652650
/* report the result */
653-
PG_RETURN_UINT64(((uint64)b <<32) |c);
651+
return ((uint64)b <<32) |c;
654652
}
655653

656654
/*
@@ -669,8 +667,7 @@ string_hash(const void *key, Size keysize)
669667
Sizes_len=strlen((constchar*)key);
670668

671669
s_len=Min(s_len,keysize-1);
672-
returnDatumGetUInt32(hash_any((constunsignedchar*)key,
673-
(int)s_len));
670+
returnhash_bytes((constunsignedchar*)key, (int)s_len);
674671
}
675672

676673
/*
@@ -679,8 +676,7 @@ string_hash(const void *key, Size keysize)
679676
uint32
680677
tag_hash(constvoid*key,Sizekeysize)
681678
{
682-
returnDatumGetUInt32(hash_any((constunsignedchar*)key,
683-
(int)keysize));
679+
returnhash_bytes((constunsignedchar*)key, (int)keysize);
684680
}
685681

686682
/*
@@ -692,5 +688,5 @@ uint32
692688
uint32_hash(constvoid*key,Sizekeysize)
693689
{
694690
Assert(keysize==sizeof(uint32));
695-
returnDatumGetUInt32(hash_uint32(*((constuint32*)key)));
691+
returnhash_bytes_uint32(*((constuint32*)key));
696692
}

‎src/include/utils/hashutils.h

Lines changed: 31 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -20,11 +20,37 @@
2020
(((v) >> 31) & UINT64CONST(0x100000001)))
2121

2222

23-
externDatumhash_any(constunsignedchar*k,intkeylen);
24-
externDatumhash_any_extended(constunsignedchar*k,
25-
intkeylen,uint64seed);
26-
externDatumhash_uint32(uint32k);
27-
externDatumhash_uint32_extended(uint32k,uint64seed);
23+
externuint32hash_bytes(constunsignedchar*k,intkeylen);
24+
externuint64hash_bytes_extended(constunsignedchar*k,
25+
intkeylen,uint64seed);
26+
externuint32hash_bytes_uint32(uint32k);
27+
externuint64hash_bytes_uint32_extended(uint32k,uint64seed);
28+
29+
#ifndefFRONTEND
30+
staticinlineDatum
31+
hash_any(constunsignedchar*k,intkeylen)
32+
{
33+
returnUInt32GetDatum(hash_bytes(k,keylen));
34+
}
35+
36+
staticinlineDatum
37+
hash_any_extended(constunsignedchar*k,intkeylen,uint64seed)
38+
{
39+
returnUInt64GetDatum(hash_bytes_extended(k,keylen,seed));
40+
}
41+
42+
staticinlineDatum
43+
hash_uint32(uint32k)
44+
{
45+
returnUInt32GetDatum(hash_bytes_uint32(k));
46+
}
47+
48+
staticinlineDatum
49+
hash_uint32_extended(uint32k,uint64seed)
50+
{
51+
returnUInt64GetDatum(hash_bytes_uint32_extended(k,seed));
52+
}
53+
#endif
2854

2955
externuint32string_hash(constvoid*key,Sizekeysize);
3056
externuint32tag_hash(constvoid*key,Sizekeysize);

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