Commit791961f

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Add inline murmurhash32(uint32) function.

The function already existed in tidbitmap.c but more users requiringfast hashing of 32bit ints are coming up.Author: Andres FreundDiscussion:https://postgr.es/m/20170914061207.zxotvyopetm7lrrp@alap3.anarazel.de

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+20

-18

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+20

-18

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Lines changed: 2 additions & 18 deletions

Original file line number	Diff line number	Diff line change
`@@ -45,6 +45,7 @@`
`45`	`45`	`#include"nodes/tidbitmap.h"`
`46`	`46`	`#include"storage/lwlock.h"`
`47`	`47`	`#include"utils/dsa.h"`
	`48`	`+#include"utils/hashutils.h"`
`48`	`49`
`49`	`50`	`/*`
`50`	`51`	`* The maximum number of tuples per page is not large (typically 256 with`
`@@ -237,30 +238,13 @@ static inttbm_comparator(const void left, const void right);`
`237`	`238`	`staticinttbm_shared_comparator(constvoidleft,constvoidright,`
`238`	`239`	`void*arg);`
`239`	`240`
`240`		`-/*`
`241`		`- * Simple inline murmur hash implementation for the exact width required, for`
`242`		`- * performance.`
`243`		`- */`
`244`		`-staticinlineuint32`
`245`		`-hash_blockno(BlockNumberb)`
`246`		`-{`
`247`		`-uint32h=b;`
`248`		`-`
`249`		`-h ^=h >>16;`
`250`		`-h *=0x85ebca6b;`
`251`		`-h ^=h >>13;`
`252`		`-h *=0xc2b2ae35;`
`253`		`-h ^=h >>16;`
`254`		`-returnh;`
`255`		`-}`
`256`		`-`
`257`	`241`	`/* define hashtable mapping block numbers to PagetableEntry's */`
`258`	`242`	`#defineSH_USE_NONDEFAULT_ALLOCATOR`
`259`	`243`	`#defineSH_PREFIX pagetable`
`260`	`244`	`#defineSH_ELEMENT_TYPE PagetableEntry`
`261`	`245`	`#defineSH_KEY_TYPE BlockNumber`
`262`	`246`	`#defineSH_KEY blockno`
`263`		`-#defineSH_HASH_KEY(tb,key)hash_blockno(key)`
	`247`	`+#defineSH_HASH_KEY(tb,key)murmurhash32(key)`
`264`	`248`	`#defineSH_EQUAL(tb,a,b) a == b`
`265`	`249`	`#defineSH_SCOPE static inline`
`266`	`250`	`#defineSH_DEFINE`

Lines changed: 18 additions & 0 deletions

Original file line number	Diff line number	Diff line change
`@@ -20,4 +20,22 @@ hash_combine(uint32 a, uint32 b)`
`20`	`20`	`returna;`
`21`	`21`	`}`
`22`	`22`
	`23`	`+`
	`24`	`+/*`
	`25`	`+ * Simple inline murmur hash implementation hashing a 32 bit ingeger, for`
	`26`	`+ * performance.`
	`27`	`+ */`
	`28`	`+staticinlineuint32`
	`29`	`+murmurhash32(uint32data)`
	`30`	`+{`
	`31`	`+uint32h=data;`
	`32`	`+`
	`33`	`+h ^=h >>16;`
	`34`	`+h *=0x85ebca6b;`
	`35`	`+h ^=h >>13;`
	`36`	`+h *=0xc2b2ae35;`
	`37`	`+h ^=h >>16;`
	`38`	`+returnh;`
	`39`	`+}`
	`40`	`+`
`23`	`41`	`#endif/* HASHUTILS_H */`

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