thodg/libgit2/src/vector.c

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• Hash : 0b0a6b11
  Author :
  Date : 2011-07-01T00:48:37
  

  vector, index: use git__msort() for vector sorting Index operation use git_vector_sort() to sort index entries. Since index support adding duplicates (two or more entries with the same path), it's important to preserve order of elements. Preserving order of elements allows to make decisions based on order. For example it's possible to implement function witch removes all duplicates except last added. Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>

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• src/vector.c

• /*
   * This file is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License, version 2,
   * as published by the Free Software Foundation.
   *
   * In addition to the permissions in the GNU General Public License,
   * the authors give you unlimited permission to link the compiled
   * version of this file into combinations with other programs,
   * and to distribute those combinations without any restriction
   * coming from the use of this file.  (The General Public License
   * restrictions do apply in other respects; for example, they cover
   * modification of the file, and distribution when not linked into
   * a combined executable.)
   *
   * This file is distributed in the hope that it will be useful, but
   * WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; see the file COPYING.  If not, write to
   * the Free Software Foundation, 51 Franklin Street, Fifth Floor,
   * Boston, MA 02110-1301, USA.
   */
  
  #include "common.h"
  #include "repository.h"
  #include "vector.h"
  
  static const double resize_factor = 1.75;
  static const size_t minimum_size = 8;
  
  static int resize_vector(git_vector *v)
  {
  	v->_alloc_size = ((unsigned int)(v->_alloc_size * resize_factor)) + 1;
  	if (v->_alloc_size < minimum_size)
  		v->_alloc_size = minimum_size;
  
  	v->contents = realloc(v->contents, v->_alloc_size * sizeof(void *));
  	if (v->contents == NULL)
  		return GIT_ENOMEM;
  
  	return GIT_SUCCESS;
  }
  
  
  void git_vector_free(git_vector *v)
  {
  	assert(v);
  	free(v->contents);
  }
  
  int git_vector_init(git_vector *v, unsigned int initial_size, git_vector_cmp cmp)
  {
  	assert(v);
  
  	memset(v, 0x0, sizeof(git_vector));
  
  	if (initial_size == 0)
  		initial_size = minimum_size;
  
  	v->_alloc_size = initial_size;
  	v->_cmp = cmp;
  
  	v->length = 0;
  	v->sorted = 1;
  
  	v->contents = git__malloc(v->_alloc_size * sizeof(void *));
  	if (v->contents == NULL)
  		return GIT_ENOMEM;
  
  	return GIT_SUCCESS;
  }
  
  int git_vector_insert(git_vector *v, void *element)
  {
  	assert(v);
  
  	if (v->length >= v->_alloc_size) {
  		if (resize_vector(v) < 0)
  			return GIT_ENOMEM;
  	}
  
  	v->contents[v->length++] = element;
  	v->sorted = 0;
  
  	return GIT_SUCCESS;
  }
  
  void git_vector_sort(git_vector *v)
  {
  	assert(v);
  
  	if (v->sorted || v->_cmp == NULL)
  		return;
  
  	git__msort(v->contents, v->length, sizeof(void *), v->_cmp);
  	v->sorted = 1;
  }
  
  int git_vector_bsearch2(git_vector *v, git_vector_cmp key_lookup, const void *key)
  {
  	void **find;
  
  	assert(v && key && key_lookup);
  
  	/* need comparison function to sort the vector */
  	if (v->_cmp == NULL)
  		return git__throw(GIT_ENOTFOUND, "Can't sort vector. No comparison function set");
  
  	git_vector_sort(v);
  
  	find = bsearch(key, v->contents, v->length, sizeof(void *), key_lookup);
  	if (find != NULL)
  		return (int)(find - v->contents);
  
  	return git__throw(GIT_ENOTFOUND, "Can't find element");
  }
  
  int git_vector_search2(git_vector *v, git_vector_cmp key_lookup, const void *key)
  {
  	unsigned int i;
  
  	assert(v && key && key_lookup);
  
  	for (i = 0; i < v->length; ++i) {
  		if (key_lookup(key, v->contents[i]) == 0)
  			return i;
  	}
  
  	return git__throw(GIT_ENOTFOUND, "Can't find element");
  }
  
  static int strict_comparison(const void *a, const void *b)
  {
  	return (a == b) ? 0 : -1;
  }
  
  int git_vector_search(git_vector *v, const void *entry)
  {
  	return git_vector_search2(v, v->_cmp ? v->_cmp : strict_comparison, entry);
  }
  
  int git_vector_bsearch(git_vector *v, const void *key)
  {
  	return git_vector_bsearch2(v, v->_cmp, key);
  }
  
  int git_vector_remove(git_vector *v, unsigned int idx)
  {
  	unsigned int i;
  
  	assert(v);
  
  	if (idx >= v->length || v->length == 0)
  		return git__throw(GIT_ENOTFOUND, "Can't remove element. Index out of bounds");
  
  	for (i = idx; i < v->length - 1; ++i)
  		v->contents[i] = v->contents[i + 1];
  
  	v->length--;
  	return GIT_SUCCESS;
  }
  
  void git_vector_clear(git_vector *v)
  {
  	assert(v);
  	v->length = 0;
  	v->sorted = 1;
  }
  
  
  

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