thodg/libgit2/src/util/vector.c

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• Hash : c3b7ace9
  Author :
  Date : 2021-11-14T16:43:53
  

  refactor: make util an object library Instead of simply including the utility files directly, make them a cmake object library for easy reusability between other projects within libgit2. Now the top-level `src` is responsible for platform selection, while the next-level `libgit2` and `util` configurations are responsible for identifying what objects they include.

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• src/util/vector.c

• /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  
  #include "vector.h"
  
  #include "integer.h"
  
  /* In elements, not bytes */
  #define MIN_ALLOCSIZE	8
  
  GIT_INLINE(size_t) compute_new_size(git_vector *v)
  {
  	size_t new_size = v->_alloc_size;
  
  	/* Use a resize factor of 1.5, which is quick to compute using integer
  	 * instructions and less than the golden ratio (1.618...) */
  	if (new_size < MIN_ALLOCSIZE)
  		new_size = MIN_ALLOCSIZE;
  	else if (new_size <= (SIZE_MAX / 3) * 2)
  		new_size += new_size / 2;
  	else
  		new_size = SIZE_MAX;
  
  	return new_size;
  }
  
  GIT_INLINE(int) resize_vector(git_vector *v, size_t new_size)
  {
  	void *new_contents;
  
  	if (new_size == 0)
  		return 0;
  
  	new_contents = git__reallocarray(v->contents, new_size, sizeof(void *));
  	GIT_ERROR_CHECK_ALLOC(new_contents);
  
  	v->_alloc_size = new_size;
  	v->contents = new_contents;
  
  	return 0;
  }
  
  int git_vector_size_hint(git_vector *v, size_t size_hint)
  {
  	if (v->_alloc_size >= size_hint)
  		return 0;
  	return resize_vector(v, size_hint);
  }
  
  int git_vector_dup(git_vector *v, const git_vector *src, git_vector_cmp cmp)
  {
  	GIT_ASSERT_ARG(v);
  	GIT_ASSERT_ARG(src);
  
  	v->_alloc_size = 0;
  	v->contents = NULL;
  	v->_cmp = cmp ? cmp : src->_cmp;
  	v->length = src->length;
  	v->flags  = src->flags;
  	if (cmp != src->_cmp)
  		git_vector_set_sorted(v, 0);
  
  	if (src->length) {
  		size_t bytes;
  		GIT_ERROR_CHECK_ALLOC_MULTIPLY(&bytes, src->length, sizeof(void *));
  		v->contents = git__malloc(bytes);
  		GIT_ERROR_CHECK_ALLOC(v->contents);
  		v->_alloc_size = src->length;
  		memcpy(v->contents, src->contents, bytes);
  	}
  
  	return 0;
  }
  
  void git_vector_free(git_vector *v)
  {
  	if (!v)
  		return;
  
  	git__free(v->contents);
  	v->contents = NULL;
  
  	v->length = 0;
  	v->_alloc_size = 0;
  }
  
  void git_vector_free_deep(git_vector *v)
  {
  	size_t i;
  
  	if (!v)
  		return;
  
  	for (i = 0; i < v->length; ++i) {
  		git__free(v->contents[i]);
  		v->contents[i] = NULL;
  	}
  
  	git_vector_free(v);
  }
  
  int git_vector_init(git_vector *v, size_t initial_size, git_vector_cmp cmp)
  {
  	GIT_ASSERT_ARG(v);
  
  	v->_alloc_size = 0;
  	v->_cmp = cmp;
  	v->length = 0;
  	v->flags = GIT_VECTOR_SORTED;
  	v->contents = NULL;
  
  	return resize_vector(v, max(initial_size, MIN_ALLOCSIZE));
  }
  
  void **git_vector_detach(size_t *size, size_t *asize, git_vector *v)
  {
  	void **data = v->contents;
  
  	if (size)
  		*size = v->length;
  	if (asize)
  		*asize = v->_alloc_size;
  
  	v->_alloc_size = 0;
  	v->length   = 0;
  	v->contents = NULL;
  
  	return data;
  }
  
  int git_vector_insert(git_vector *v, void *element)
  {
  	GIT_ASSERT_ARG(v);
  
  	if (v->length >= v->_alloc_size &&
  		resize_vector(v, compute_new_size(v)) < 0)
  		return -1;
  
  	v->contents[v->length++] = element;
  
  	git_vector_set_sorted(v, v->length <= 1);
  
  	return 0;
  }
  
  int git_vector_insert_sorted(
  	git_vector *v, void *element, int (*on_dup)(void **old, void *new))
  {
  	int result;
  	size_t pos;
  
  	GIT_ASSERT_ARG(v);
  	GIT_ASSERT(v->_cmp);
  
  	if (!git_vector_is_sorted(v))
  		git_vector_sort(v);
  
  	if (v->length >= v->_alloc_size &&
  		resize_vector(v, compute_new_size(v)) < 0)
  		return -1;
  
  	/* If we find the element and have a duplicate handler callback,
  	 * invoke it.  If it returns non-zero, then cancel insert, otherwise
  	 * proceed with normal insert.
  	 */
  	if (!git__bsearch(v->contents, v->length, element, v->_cmp, &pos) &&
  		on_dup && (result = on_dup(&v->contents[pos], element)) < 0)
  		return result;
  
  	/* shift elements to the right */
  	if (pos < v->length)
  		memmove(v->contents + pos + 1, v->contents + pos,
  		        (v->length - pos) * sizeof(void *));
  
  	v->contents[pos] = element;
  	v->length++;
  
  	return 0;
  }
  
  void git_vector_sort(git_vector *v)
  {
  	if (git_vector_is_sorted(v) || !v->_cmp)
  		return;
  
  	if (v->length > 1)
  		git__tsort(v->contents, v->length, v->_cmp);
  	git_vector_set_sorted(v, 1);
  }
  
  int git_vector_bsearch2(
  	size_t *at_pos,
  	git_vector *v,
  	git_vector_cmp key_lookup,
  	const void *key)
  {
  	GIT_ASSERT_ARG(v);
  	GIT_ASSERT_ARG(key);
  	GIT_ASSERT(key_lookup);
  
  	/* need comparison function to sort the vector */
  	if (!v->_cmp)
  		return -1;
  
  	git_vector_sort(v);
  
  	return git__bsearch(v->contents, v->length, key, key_lookup, at_pos);
  }
  
  int git_vector_search2(
  	size_t *at_pos, const git_vector *v, git_vector_cmp key_lookup, const void *key)
  {
  	size_t i;
  
  	GIT_ASSERT_ARG(v);
  	GIT_ASSERT_ARG(key);
  	GIT_ASSERT(key_lookup);
  
  	for (i = 0; i < v->length; ++i) {
  		if (key_lookup(key, v->contents[i]) == 0) {
  			if (at_pos)
  				*at_pos = i;
  
  			return 0;
  		}
  	}
  
  	return GIT_ENOTFOUND;
  }
  
  static int strict_comparison(const void *a, const void *b)
  {
  	return (a == b) ? 0 : -1;
  }
  
  int git_vector_search(size_t *at_pos, const git_vector *v, const void *entry)
  {
  	return git_vector_search2(at_pos, v, v->_cmp ? v->_cmp : strict_comparison, entry);
  }
  
  int git_vector_remove(git_vector *v, size_t idx)
  {
  	size_t shift_count;
  
  	GIT_ASSERT_ARG(v);
  
  	if (idx >= v->length)
  		return GIT_ENOTFOUND;
  
  	shift_count = v->length - idx - 1;
  
  	if (shift_count)
  		memmove(&v->contents[idx], &v->contents[idx + 1],
  			shift_count * sizeof(void *));
  
  	v->length--;
  	return 0;
  }
  
  void git_vector_pop(git_vector *v)
  {
  	if (v->length > 0)
  		v->length--;
  }
  
  void git_vector_uniq(git_vector *v, void  (*git_free_cb)(void *))
  {
  	git_vector_cmp cmp;
  	size_t i, j;
  
  	if (v->length <= 1)
  		return;
  
  	git_vector_sort(v);
  	cmp = v->_cmp ? v->_cmp : strict_comparison;
  
  	for (i = 0, j = 1 ; j < v->length; ++j)
  		if (!cmp(v->contents[i], v->contents[j])) {
  			if (git_free_cb)
  				git_free_cb(v->contents[i]);
  
  			v->contents[i] = v->contents[j];
  		} else
  			v->contents[++i] = v->contents[j];
  
  	v->length -= j - i - 1;
  }
  
  void git_vector_remove_matching(
  	git_vector *v,
  	int (*match)(const git_vector *v, size_t idx, void *payload),
  	void *payload)
  {
  	size_t i, j;
  
  	for (i = 0, j = 0; j < v->length; ++j) {
  		v->contents[i] = v->contents[j];
  
  		if (!match(v, i, payload))
  			i++;
  	}
  
  	v->length = i;
  }
  
  void git_vector_clear(git_vector *v)
  {
  	v->length = 0;
  	git_vector_set_sorted(v, 1);
  }
  
  void git_vector_swap(git_vector *a, git_vector *b)
  {
  	git_vector t;
  
  	if (a != b) {
  		memcpy(&t, a, sizeof(t));
  		memcpy(a, b, sizeof(t));
  		memcpy(b, &t, sizeof(t));
  	}
  }
  
  int git_vector_resize_to(git_vector *v, size_t new_length)
  {
  	if (new_length > v->_alloc_size &&
  		resize_vector(v, new_length) < 0)
  		return -1;
  
  	if (new_length > v->length)
  		memset(&v->contents[v->length], 0,
  			sizeof(void *) * (new_length - v->length));
  
  	v->length = new_length;
  
  	return 0;
  }
  
  int git_vector_insert_null(git_vector *v, size_t idx, size_t insert_len)
  {
  	size_t new_length;
  
  	GIT_ASSERT_ARG(insert_len > 0);
  	GIT_ASSERT_ARG(idx <= v->length);
  
  	GIT_ERROR_CHECK_ALLOC_ADD(&new_length, v->length, insert_len);
  
  	if (new_length > v->_alloc_size && resize_vector(v, new_length) < 0)
  		return -1;
  
  	memmove(&v->contents[idx + insert_len], &v->contents[idx],
  		sizeof(void *) * (v->length - idx));
  	memset(&v->contents[idx], 0, sizeof(void *) * insert_len);
  
  	v->length = new_length;
  	return 0;
  }
  
  int git_vector_remove_range(git_vector *v, size_t idx, size_t remove_len)
  {
  	size_t new_length = v->length - remove_len;
  	size_t end_idx = 0;
  
  	GIT_ASSERT_ARG(remove_len > 0);
  
  	if (git__add_sizet_overflow(&end_idx, idx, remove_len))
  		GIT_ASSERT(0);
  
  	GIT_ASSERT(end_idx <= v->length);
  
  	if (end_idx < v->length)
  		memmove(&v->contents[idx], &v->contents[end_idx],
  			sizeof(void *) * (v->length - end_idx));
  
  	memset(&v->contents[new_length], 0, sizeof(void *) * remove_len);
  
  	v->length = new_length;
  	return 0;
  }
  
  int git_vector_set(void **old, git_vector *v, size_t position, void *value)
  {
  	if (position + 1 > v->length) {
  		if (git_vector_resize_to(v, position + 1) < 0)
  			return -1;
  	}
  
  	if (old != NULL)
  		*old = v->contents[position];
  
  	v->contents[position] = value;
  
  	return 0;
  }
  
  int git_vector_verify_sorted(const git_vector *v)
  {
  	size_t i;
  
  	if (!git_vector_is_sorted(v))
  		return -1;
  
  	for (i = 1; i < v->length; ++i) {
  		if (v->_cmp(v->contents[i - 1], v->contents[i]) > 0)
  			return -1;
  	}
  
  	return 0;
  }
  
  void git_vector_reverse(git_vector *v)
  {
  	size_t a, b;
  
  	if (v->length == 0)
  		return;
  
  	a = 0;
  	b = v->length - 1;
  
  	while (a < b) {
  		void *tmp = v->contents[a];
  		v->contents[a] = v->contents[b];
  		v->contents[b] = tmp;
  		a++;
  		b--;
  	}
  }
  

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