thodg/libgit2/src/oidmap.h

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• Hash : f6b26e77
  Author :
  Date : 2012-07-27T10:53:09
  

  git_oid_cmp: inline memcmp by hand to optimize
  
  git.git uses an inlined hashcmp function instead of memcmp, since it
  performes much better when comparing hashes (most hashes compared
  diverge within the first byte).
  
  Measurements and rationale for the curious reader:
  http://thread.gmane.org/gmane.comp.version-control.git/172286
  

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• src/oidmap.h

• /*
   * Copyright (C) 2012 the libgit2 contributors
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  #ifndef INCLUDE_oidmap_h__
  #define INCLUDE_oidmap_h__
  
  #include "common.h"
  #include "git2/oid.h"
  
  #define kmalloc git__malloc
  #define kcalloc git__calloc
  #define krealloc git__realloc
  #define kfree git__free
  #include "khash.h"
  
  __KHASH_TYPE(oid, const git_oid *, void *);
  typedef khash_t(oid) git_oidmap;
  
  GIT_INLINE(khint_t) hash_git_oid(const git_oid *oid)
  {
  	int i;
  	khint_t h = 0;
  	for (i = 0; i < 20; ++i)
  		h = (h << 5) - h + oid->id[i];
  	return h;
  }
  
  #define GIT__USE_OIDMAP \
  	__KHASH_IMPL(oid, static kh_inline, const git_oid *, void *, 1, hash_git_oid, git_oid_equal)
  
  #define git_oidmap_alloc() kh_init(oid)
  #define git_oidmap_free(h) kh_destroy(oid,h), h = NULL
  
  #endif
  

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