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  • Committer: Mark Atwood
  • Date: 2011-09-14 03:30:42 UTC
  • mfrom: (2409.2.6 refactor7)
  • Revision ID: me@mark.atwood.name-20110914033042-2u0s8foaigvf62g2
merge lp:~olafvdspek/drizzle/refactor7

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plugin/myisam/mi_create.cc
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using namespace drizzled;
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/*
 
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  Next highest power of two
 
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  SYNOPSIS
 
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    my_round_up_to_next_power()
 
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    v           Value to check
 
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  RETURN
 
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    Next or equal power of 2
 
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    Note: 0 will return 0
 
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  NOTES
 
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    Algorithm by Sean Anderson, according to:
 
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    http://graphics.stanford.edu/~seander/bithacks.html
 
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    (Orignal code public domain)
 
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    Comments shows how this works with 01100000000000000000000000001011
 
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*/
 
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static inline uint32_t my_round_up_to_next_power(uint32_t v)
 
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{
 
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  v--;                  /* 01100000000000000000000000001010 */
 
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  v|= v >> 1;           /* 01110000000000000000000000001111 */
 
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  v|= v >> 2;           /* 01111100000000000000000000001111 */
 
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  v|= v >> 4;           /* 01111111110000000000000000001111 */
 
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  v|= v >> 8;           /* 01111111111111111100000000001111 */
 
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  v|= v >> 16;          /* 01111111111111111111111111111111 */
 
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  return v+1;           /* 10000000000000000000000000000000 */
 
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}
 
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/*
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  Old options is used when recreating database, from myisamchk
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*/
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