Merge pull request #2100 from libgit2/rb/update-pqueue

Replace priority queue code with implementation from hashsig

12 files changed, 173 insertions, 247 deletions

diff --git a/src/commit_list.c b/src/commit_list.c
index 64416e54d..9db3f5633 100644
--- a/src/commit_list.c
+++ b/src/commit_list.c
@@ -11,10 +11,10 @@
 #include "pool.h"
 #include "odb.h"
 
-int git_commit_list_time_cmp(void *a, void *b)
+int git_commit_list_time_cmp(const void *a, const void *b)
 {
-	git_commit_list_node *commit_a = (git_commit_list_node *)a;
-	git_commit_list_node *commit_b = (git_commit_list_node *)b;
+	const git_commit_list_node *commit_a = a;
+	const git_commit_list_node *commit_b = b;
 
 	return (commit_a->time < commit_b->time);
 }
diff --git a/src/commit_list.h b/src/commit_list.h
index d2f54b3ca..490d841be 100644
--- a/src/commit_list.h
+++ b/src/commit_list.h
@@ -39,7 +39,7 @@ typedef struct git_commit_list {
 } git_commit_list;
 
 git_commit_list_node *git_commit_list_alloc_node(git_revwalk *walk);
-int git_commit_list_time_cmp(void *a, void *b);
+int git_commit_list_time_cmp(const void *a, const void *b);
 void git_commit_list_free(git_commit_list **list_p);
 git_commit_list *git_commit_list_insert(git_commit_list_node *item, git_commit_list **list_p);
 git_commit_list *git_commit_list_insert_by_date(git_commit_list_node *item, git_commit_list **list_p);
diff --git a/src/graph.c b/src/graph.c
index f39af5ed5..96fda7add 100644
--- a/src/graph.c
+++ b/src/graph.c
@@ -1,4 +1,3 @@
-
 /*
  * Copyright (C) the libgit2 contributors. All rights reserved.
  *
@@ -13,9 +12,9 @@
 static int interesting(git_pqueue *list, git_commit_list *roots)
 {
 	unsigned int i;
-	/* element 0 isn't used - we need to start at 1 */
-	for (i = 1; i < list->size; i++) {
-		git_commit_list_node *commit = list->d[i];
+
+	for (i = 0; i < git_pqueue_size(list); i++) {
+		git_commit_list_node *commit = git_pqueue_get(list, i);
 		if ((commit->flags & STALE) == 0)
 			return 1;
 	}
@@ -42,7 +41,7 @@ static int mark_parents(git_revwalk *walk, git_commit_list_node *one,
 		return 0;
 	}
 
-	if (git_pqueue_init(&list, 2, git_commit_list_time_cmp) < 0)
+	if (git_pqueue_init(&list, 0, 2, git_commit_list_time_cmp) < 0)
 		return -1;
 
 	if (git_commit_list_parse(walk, one) < 0)
@@ -59,10 +58,9 @@ static int mark_parents(git_revwalk *walk, git_commit_list_node *one,
 
 	/* as long as there are non-STALE commits */
 	while (interesting(&list, roots)) {
-		git_commit_list_node *commit;
+		git_commit_list_node *commit = git_pqueue_pop(&list);
 		int flags;
 
-		commit = git_pqueue_pop(&list);
 		if (commit == NULL)
 			break;
 
@@ -110,16 +108,16 @@ static int ahead_behind(git_commit_list_node *one, git_commit_list_node *two,
 {
 	git_commit_list_node *commit;
 	git_pqueue pq;
-	int i;
+	int error = 0, i;
 	*ahead = 0;
 	*behind = 0;
 
-	if (git_pqueue_init(&pq, 2, git_commit_list_time_cmp) < 0)
+	if (git_pqueue_init(&pq, 0, 2, git_commit_list_time_cmp) < 0)
 		return -1;
-	if (git_pqueue_insert(&pq, one) < 0)
-		goto on_error;
-	if (git_pqueue_insert(&pq, two) < 0)
-		goto on_error;
+
+	if ((error = git_pqueue_insert(&pq, one)) < 0 ||
+		(error = git_pqueue_insert(&pq, two)) < 0)
+		goto done;
 
 	while ((commit = git_pqueue_pop(&pq)) != NULL) {
 		if (commit->flags & RESULT ||
@@ -132,18 +130,15 @@ static int ahead_behind(git_commit_list_node *one, git_commit_list_node *two,
 
 		for (i = 0; i < commit->out_degree; i++) {
 			git_commit_list_node *p = commit->parents[i];
-			if (git_pqueue_insert(&pq, p) < 0)
-				return -1;
+			if ((error = git_pqueue_insert(&pq, p)) < 0)
+				goto done;
 		}
 		commit->flags |= RESULT;
 	}
 
+done:
 	git_pqueue_free(&pq);
-	return 0;
-
-on_error:
-	git_pqueue_free(&pq);
-	return -1;
+	return error;
 }
 
 int git_graph_ahead_behind(size_t *ahead, size_t *behind, git_repository *repo,
diff --git a/src/index.c b/src/index.c
index 7bc5d5b24..42eb5fd49 100644
--- a/src/index.c
+++ b/src/index.c
@@ -1564,7 +1564,7 @@ static int read_reuc(git_index *index, const char *buffer, size_t size)
 	}
 
 	/* entries are guaranteed to be sorted on-disk */
-	index->reuc.sorted = 1;
+	git_vector_set_sorted(&index->reuc, true);
 
 	return 0;
 }
@@ -1610,7 +1610,7 @@ static int read_conflict_names(git_index *index, const char *buffer, size_t size
 #undef read_conflict_name
 
 	/* entries are guaranteed to be sorted on-disk */
-	index->names.sorted = 1;
+	git_vector_set_sorted(&index->names, true);
 
 	return 0;
 }
@@ -1811,8 +1811,10 @@ static int parse_index(git_index *index, const char *buffer, size_t buffer_size)
 
 #undef seek_forward
 
-	/* Entries are stored case-sensitively on disk. */
-	index->entries.sorted = !index->ignore_case;
+	/* Entries are stored case-sensitively on disk, so re-sort now if
+	 * in-memory index is supposed to be case-insensitive
+	 */
+	git_vector_set_sorted(&index->entries, !index->ignore_case);
 	git_vector_sort(&index->entries);
 
 	return 0;
diff --git a/src/merge.c b/src/merge.c
index ac973efd0..97c147920 100644
--- a/src/merge.c
+++ b/src/merge.c
@@ -161,10 +161,10 @@ on_error:
 
 static int interesting(git_pqueue *list)
 {
-	unsigned int i;
-	/* element 0 isn't used - we need to start at 1 */
-	for (i = 1; i < list->size; i++) {
-		git_commit_list_node *commit = list->d[i];
+	size_t i;
+
+	for (i = 0; i < git_pqueue_size(list); i++) {
+		git_commit_list_node *commit = git_pqueue_get(list, i);
 		if ((commit->flags & STALE) == 0)
 			return 1;
 	}
@@ -186,7 +186,7 @@ int git_merge__bases_many(git_commit_list **out, git_revwalk *walk, git_commit_l
 			return git_commit_list_insert(one, out) ? 0 : -1;
 	}
 
-	if (git_pqueue_init(&list, twos->length * 2, git_commit_list_time_cmp) < 0)
+	if (git_pqueue_init(&list, 0, twos->length * 2, git_commit_list_time_cmp) < 0)
 		return -1;
 
 	if (git_commit_list_parse(walk, one) < 0)
@@ -205,10 +205,11 @@ int git_merge__bases_many(git_commit_list **out, git_revwalk *walk, git_commit_l
 
 	/* as long as there are non-STALE commits */
 	while (interesting(&list)) {
-		git_commit_list_node *commit;
+		git_commit_list_node *commit = git_pqueue_pop(&list);
 		int flags;
 
-		commit = git_pqueue_pop(&list);
+		if (commit == NULL)
+			break;
 
 		flags = commit->flags & (PARENT1 | PARENT2 | STALE);
 		if (flags == (PARENT1 | PARENT2)) {
diff --git a/src/pqueue.c b/src/pqueue.c
index 7819ed41e..172cf43d5 100644
--- a/src/pqueue.c
+++ b/src/pqueue.c
@@ -3,161 +3,115 @@
  *
  * This file is part of libgit2, distributed under the GNU GPL v2 with
  * a Linking Exception. For full terms see the included COPYING file.
- *
- * This file is based on a modified version of the priority queue found
- * in the Apache project and libpqueue library.
- * 
- * https://github.com/vy/libpqueue
- * 
- * Original file notice:
- * 
- * Copyright 2010 Volkan Yazici <volkan.yazici@gmail.com>
- * Copyright 2006-2010 The Apache Software Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations under
- * the License.
  */
 
-#include "common.h"
 #include "pqueue.h"
+#include "util.h"
 
-#define left(i)	((i) << 1)
-#define right(i) (((i) << 1) + 1)
-#define parent(i) ((i) >> 1)
+#define PQUEUE_LCHILD_OF(I) (((I)<<1)+1)
+#define PQUEUE_RCHILD_OF(I) (((I)<<1)+2)
+#define PQUEUE_PARENT_OF(I) (((I)-1)>>1)
 
-int git_pqueue_init(git_pqueue *q, size_t n, git_pqueue_cmp cmppri)
+int git_pqueue_init(
+	git_pqueue *pq,
+	uint32_t flags,
+	size_t init_size,
+	git_vector_cmp cmp)
 {
-	assert(q);
+	int error = git_vector_init(pq, init_size, cmp);
 
-	/* Need to allocate n+1 elements since element 0 isn't used. */
-	q->d = git__malloc((n + 1) * sizeof(void *));
-	GITERR_CHECK_ALLOC(q->d);
+	if (!error) {
+		/* mix in our flags */
+		pq->flags |= flags;
 
-	q->size = 1;
-	q->avail = q->step = (n + 1); /* see comment above about n+1 */
-	q->cmppri = cmppri;
+		/* if fixed size heap, pretend vector is exactly init_size elements */
+		if ((flags & GIT_PQUEUE_FIXED_SIZE) && init_size > 0)
+			pq->_alloc_size = init_size;
+	}
 
-	return 0;
+	return error;
 }
 
-
-void git_pqueue_free(git_pqueue *q)
+static void pqueue_up(git_pqueue *pq, size_t el)
 {
-	git__free(q->d);
-	q->d = NULL;
-}
+	size_t parent_el = PQUEUE_PARENT_OF(el);
+	void *kid = git_vector_get(pq, el);
 
-void git_pqueue_clear(git_pqueue *q)
-{
-	q->size = 1;
-}
+	while (el > 0) {
+		void *parent = pq->contents[parent_el];
 
-size_t git_pqueue_size(git_pqueue *q)
-{
-	/* queue element 0 exists but doesn't count since it isn't used. */
-	return (q->size - 1);
-}
+		if (pq->_cmp(parent, kid) <= 0)
+			break;
 
+		pq->contents[el] = parent;
 
-static void bubble_up(git_pqueue *q, size_t i)
-{
-	size_t parent_node;
-	void *moving_node = q->d[i];
-
-	for (parent_node = parent(i);
-			((i > 1) && q->cmppri(q->d[parent_node], moving_node));
-			i = parent_node, parent_node = parent(i)) {
-		q->d[i] = q->d[parent_node];
+		el = parent_el;
+		parent_el = PQUEUE_PARENT_OF(el);
 	}
 
-	q->d[i] = moving_node;
+	pq->contents[el] = kid;
 }
 
-
-static size_t maxchild(git_pqueue *q, size_t i)
+static void pqueue_down(git_pqueue *pq, size_t el)
 {
-	size_t child_node = left(i);
+	void *parent = git_vector_get(pq, el), *kid, *rkid;
 
-	if (child_node >= q->size)
-		return 0;
+	while (1) {
+		size_t kid_el = PQUEUE_LCHILD_OF(el);
 
-	if ((child_node + 1) < q->size &&
-		q->cmppri(q->d[child_node], q->d[child_node + 1]))
-		child_node++; /* use right child instead of left */
+		if ((kid = git_vector_get(pq, kid_el)) == NULL)
+			break;
 
-	return child_node;
-}
+		if ((rkid = git_vector_get(pq, kid_el + 1)) != NULL &&
+			pq->_cmp(kid, rkid) > 0) {
+			kid    = rkid;
+			kid_el += 1;
+		}
 
+		if (pq->_cmp(parent, kid) < 0)
+			break;
 
-static void percolate_down(git_pqueue *q, size_t i)
-{
-	size_t child_node;
-	void *moving_node = q->d[i];
-
-	while ((child_node = maxchild(q, i)) != 0 &&
-			q->cmppri(moving_node, q->d[child_node])) {
-		q->d[i] = q->d[child_node];
-		i = child_node;
+		pq->contents[el] = kid;
+		el = kid_el;
 	}
 
-	q->d[i] = moving_node;
+	pq->contents[el] = parent;
 }
 
-
-int git_pqueue_insert(git_pqueue *q, void *d)
+int git_pqueue_insert(git_pqueue *pq, void *item)
 {
-	void *tmp;
-	size_t i;
-	size_t newsize;
-
-	if (!q) return 1;
-
-	/* allocate more memory if necessary */
-	if (q->size >= q->avail) {
-		newsize = q->size + q->step;
-		tmp = git__realloc(q->d, sizeof(void *) * newsize);
-		GITERR_CHECK_ALLOC(tmp);
-
-		q->d = tmp;
-		q->avail = newsize;
+	int error = 0;
+
+	/* if heap is full, pop the top element if new one should replace it */
+	if ((pq->flags & GIT_PQUEUE_FIXED_SIZE) != 0 &&
+		pq->length >= pq->_alloc_size)
+	{
+		/* skip this item if below min item in heap */
+		if (pq->_cmp(item, git_vector_get(pq, 0)) <= 0)
+			return 0;
+		/* otherwise remove the min item before inserting new */
+		(void)git_pqueue_pop(pq);
 	}
 
-	/* insert item */
-	i = q->size++;
-	q->d[i] = d;
-	bubble_up(q, i);
+	if (!(error = git_vector_insert(pq, item)))
+		pqueue_up(pq, pq->length - 1);
 
-	return 0;
+	return error;
 }
 
-
-void *git_pqueue_pop(git_pqueue *q)
+void *git_pqueue_pop(git_pqueue *pq)
 {
-	void *head;
-
-	if (!q || q->size == 1)
-		return NULL;
-
-	head = q->d[1];
-	q->d[1] = q->d[--q->size];
-	percolate_down(q, 1);
-
-	return head;
-}
-
+	void *rval = git_pqueue_get(pq, 0);
+
+	if (git_pqueue_size(pq) > 1) {
+		/* move last item to top of heap, shrink, and push item down */
+		pq->contents[0] = git_vector_last(pq);
+		git_vector_pop(pq);
+		pqueue_down(pq, 0);
+	} else {
+		/* all we need to do is shrink the heap in this case */
+		git_vector_pop(pq);
+	}
 
-void *git_pqueue_peek(git_pqueue *q)
-{
-	if (!q || q->size == 1)
-		return NULL;
-	return q->d[1];
+	return rval;
 }
diff --git a/src/pqueue.h b/src/pqueue.h
index 9061f8279..da7b74edf 100644
--- a/src/pqueue.h
+++ b/src/pqueue.h
@@ -3,99 +3,54 @@
  *
  * This file is part of libgit2, distributed under the GNU GPL v2 with
  * a Linking Exception. For full terms see the included COPYING file.
- * 
- * This file is based on a modified version of the priority queue found
- * in the Apache project and libpqueue library.
- * 
- * https://github.com/vy/libpqueue
- * 
- * Original file notice:
- * 
- * Copyright 2010 Volkan Yazici <volkan.yazici@gmail.com>
- * Copyright 2006-2010 The Apache Software Foundation
- *
- * Licensed under the Apache License, Version 2.0 (the "License"); you may not
- * use this file except in compliance with the License. You may obtain a copy of
- * the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations under
- * the License.
  */
-
 #ifndef INCLUDE_pqueue_h__
 #define INCLUDE_pqueue_h__
 
-/** callback functions to get/set/compare the priority of an element */
-typedef int (*git_pqueue_cmp)(void *a, void *b);
+#include "vector.h"
 
-/** the priority queue handle */
-typedef struct {
-	size_t size, avail, step;
-	git_pqueue_cmp cmppri;
-	void **d;
-} git_pqueue;
+typedef git_vector git_pqueue;
 
+enum {
+	/* flag meaning: don't grow heap, keep highest values only */
+	GIT_PQUEUE_FIXED_SIZE = (GIT_VECTOR_FLAG_MAX << 1),
+};
 
 /**
- * initialize the queue
+ * Initialize priority queue
  *
- * @param n the initial estimate of the number of queue items for which memory
- *			should be preallocated
- * @param cmppri the callback function to compare two nodes of the queue
- *
- * @return the handle or NULL for insufficent memory
- */
-int git_pqueue_init(git_pqueue *q, size_t n, git_pqueue_cmp cmppri);
-
-
-/**
- * free all memory used by the queue
- * @param q the queue
- */
-void git_pqueue_free(git_pqueue *q);
-
-/**
- * clear all the elements in the queue
- * @param q the queue
- */
-void git_pqueue_clear(git_pqueue *q);
+ * @param pq The priority queue struct to initialize
+ * @param flags Flags (see above) to control queue behavior
+ * @param init_size The initial queue size
+ * @param cmp The entry priority comparison function
+ * @return 0 on success, <0 on error
+ */
+extern int git_pqueue_init(
+	git_pqueue *pq,
+	uint32_t flags,
+	size_t init_size,
+	git_vector_cmp cmp);
+
+#define git_pqueue_free  git_vector_free
+#define git_pqueue_clear git_vector_clear
+#define git_pqueue_size  git_vector_length
+#define git_pqueue_get   git_vector_get
 
 /**
- * return the size of the queue.
- * @param q the queue
- */
-size_t git_pqueue_size(git_pqueue *q);
-
-
-/**
- * insert an item into the queue.
- * @param q the queue
- * @param d the item
- * @return 0 on success
- */
-int git_pqueue_insert(git_pqueue *q, void *d);
-
-
-/**
- * pop the highest-ranking item from the queue.
- * @param q the queue
- * @return NULL on error, otherwise the entry
+ * Insert a new item into the queue
+ *
+ * @param pq The priority queue
+ * @param item Pointer to the item data
+ * @return 0 on success, <0 on failure
  */
-void *git_pqueue_pop(git_pqueue *q);
-
+extern int git_pqueue_insert(git_pqueue *pq, void *item);
 
 /**
- * access highest-ranking item without removing it.
- * @param q the queue
- * @return NULL on error, otherwise the entry
+ * Remove the top item in the priority queue
+ *
+ * @param pq The priority queue
+ * @return item from heap on success, NULL if queue is empty
  */
-void *git_pqueue_peek(git_pqueue *q);
-
-#endif /* PQUEUE_H */
-/** @} */
+extern void *git_pqueue_pop(git_pqueue *pq);
 
+#endif
diff --git a/src/revwalk.c b/src/revwalk.c
index 628057fcd..753911246 100644
--- a/src/revwalk.c
+++ b/src/revwalk.c
@@ -451,7 +451,8 @@ int git_revwalk_new(git_revwalk **revwalk_out, git_repository *repo)
 	walk->commits = git_oidmap_alloc();
 	GITERR_CHECK_ALLOC(walk->commits);
 
-	if (git_pqueue_init(&walk->iterator_time, 8, git_commit_list_time_cmp) < 0 ||
+	if (git_pqueue_init(
+			&walk->iterator_time, 0, 8, git_commit_list_time_cmp) < 0 ||
 		git_vector_init(&walk->twos, 4, NULL) < 0 ||
 		git_pool_init(&walk->commit_pool, 1,
 			git_pool__suggest_items_per_page(COMMIT_ALLOC) * COMMIT_ALLOC) < 0)
diff --git a/src/sortedcache.c b/src/sortedcache.c
index 466e55dbe..13f0921f1 100644
--- a/src/sortedcache.c
+++ b/src/sortedcache.c
@@ -321,7 +321,7 @@ size_t git_sortedcache_entrycount(const git_sortedcache *sc)
 void *git_sortedcache_entry(git_sortedcache *sc, size_t pos)
 {
 	/* make sure the items are sorted so this gets the correct item */
-	if (!sc->items.sorted)
+	if (!git_vector_is_sorted(&sc->items))
 		git_vector_sort(&sc->items);
 
 	return git_vector_get(&sc->items, pos);
diff --git a/src/tree.c b/src/tree.c
index 877a3fcee..94f779eca 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -283,7 +283,8 @@ static const git_tree_entry *entry_fromname(
 {
 	size_t idx;
 
-	assert(tree->entries.sorted); /* be safe when we cast away constness */
+	/* be safe when we cast away constness - i.e. don't trigger a sort */
+	assert(git_vector_is_sorted(&tree->entries));
 
 	if (tree_key_search(&idx, (git_vector *)&tree->entries, name, name_len) < 0)
 		return NULL;
@@ -333,7 +334,8 @@ int git_tree__prefix_position(const git_tree *tree, const char *path)
 	ksearch.filename = path;
 	ksearch.filename_len = strlen(path);
 
-	assert(tree->entries.sorted); /* be safe when we cast away constness */
+	/* be safe when we cast away constness - i.e. don't trigger a sort */
+	assert(git_vector_is_sorted(&tree->entries));
 
 	/* Find tree entry with appropriate prefix */
 	git_vector_bsearch2(
diff --git a/src/vector.c b/src/vector.c
index f0c2f06c2..e5d8919d3 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -56,7 +56,9 @@ int git_vector_dup(git_vector *v, const git_vector *src, git_vector_cmp cmp)
 	v->_alloc_size = src->length;
 	v->_cmp = cmp;
 	v->length = src->length;
-	v->sorted = src->sorted && cmp == src->_cmp;
+	v->flags  = src->flags;
+	if (cmp != src->_cmp)
+		git_vector_set_sorted(v, 0);
 	v->contents = git__malloc(bytes);
 	GITERR_CHECK_ALLOC(v->contents);
 
@@ -97,7 +99,7 @@ int git_vector_init(git_vector *v, size_t initial_size, git_vector_cmp cmp)
 	v->_alloc_size = 0;
 	v->_cmp = cmp;
 	v->length = 0;
-	v->sorted = 1;
+	v->flags = GIT_VECTOR_SORTED;
 	v->contents = NULL;
 
 	return resize_vector(v, max(initial_size, MIN_ALLOCSIZE));
@@ -128,7 +130,8 @@ int git_vector_insert(git_vector *v, void *element)
 		return -1;
 
 	v->contents[v->length++] = element;
-	v->sorted = 0;
+
+	git_vector_set_sorted(v, v->length <= 1);
 
 	return 0;
 }
@@ -141,7 +144,7 @@ int git_vector_insert_sorted(
 
 	assert(v && v->_cmp);
 
-	if (!v->sorted)
+	if (!git_vector_is_sorted(v))
 		git_vector_sort(v);
 
 	if (v->length >= v->_alloc_size &&
@@ -171,11 +174,11 @@ void git_vector_sort(git_vector *v)
 {
 	assert(v);
 
-	if (v->sorted || !v->_cmp)
+	if (git_vector_is_sorted(v) || !v->_cmp)
 		return;
 
 	git__tsort(v->contents, v->length, v->_cmp);
-	v->sorted = 1;
+	git_vector_set_sorted(v, 1);
 }
 
 int git_vector_bsearch2(
@@ -291,7 +294,7 @@ void git_vector_clear(git_vector *v)
 {
 	assert(v);
 	v->length = 0;
-	v->sorted = 1;
+	git_vector_set_sorted(v, 1);
 }
 
 void git_vector_swap(git_vector *a, git_vector *b)
diff --git a/src/vector.h b/src/vector.h
index d318463c6..f8256853b 100644
--- a/src/vector.h
+++ b/src/vector.h
@@ -11,12 +11,17 @@
 
 typedef int (*git_vector_cmp)(const void *, const void *);
 
+enum {
+	GIT_VECTOR_SORTED = (1u << 0),
+	GIT_VECTOR_FLAG_MAX = (1u << 1),
+};
+
 typedef struct git_vector {
 	size_t _alloc_size;
 	git_vector_cmp _cmp;
 	void **contents;
 	size_t length;
-	int sorted;
+	uint32_t flags;
 } git_vector;
 
 #define GIT_VECTOR_INIT {0}
@@ -86,12 +91,20 @@ void git_vector_remove_matching(
 int git_vector_resize_to(git_vector *v, size_t new_length);
 int git_vector_set(void **old, git_vector *v, size_t position, void *value);
 
+/** Check if vector is sorted */
+#define git_vector_is_sorted(V) (((V)->flags & GIT_VECTOR_SORTED) != 0)
+
+/** Directly set sorted state of vector */
+#define git_vector_set_sorted(V,S) do { \
+	(V)->flags = (S) ? ((V)->flags | GIT_VECTOR_SORTED) : \
+		((V)->flags & ~GIT_VECTOR_SORTED); } while (0)
+
 /** Set the comparison function used for sorting the vector */
 GIT_INLINE(void) git_vector_set_cmp(git_vector *v, git_vector_cmp cmp)
 {
 	if (cmp != v->_cmp) {
 		v->_cmp = cmp;
-		v->sorted = 0;
+		git_vector_set_sorted(v, 0);
 	}
 }