thodg/libgit2

diff --git a/include/git2/status.h b/include/git2/status.h
index 0aff56a..0130b40 100644
--- a/include/git2/status.h
+++ b/include/git2/status.h
@@ -36,15 +36,18 @@ GIT_BEGIN_DECL
 /**
  * Gather file statuses and run a callback for each one.
  *
- * The callback is passed the path of the file, the status and the data pointer
- * passed to this function. If the callback returns something other than
- * GIT_SUCCESS, this function will return that value.
+ * The callback is passed the path of the file, the status and the data
+ * pointer passed to this function. If the callback returns something other
+ * than 0, this function will return that value.
  *
  * @param repo a repository object
  * @param callback the function to call on each file
- * @return GIT_SUCCESS or the return value of the callback which did not return GIT_SUCCESS
+ * @return 0 on success or the return value of the callback that was non-zero
  */
-GIT_EXTERN(int) git_status_foreach(git_repository *repo, int (*callback)(const char *, unsigned int, void *), void *payload);
+GIT_EXTERN(int) git_status_foreach(
+	git_repository *repo,
+	int (*callback)(const char *, unsigned int, void *),
+	void *payload);
 
 /**
  * Select the files on which to report status.
@@ -115,7 +118,7 @@ typedef struct {
  */
 GIT_EXTERN(int) git_status_foreach_ext(
 	git_repository *repo,
-	git_status_options *opts,
+	const git_status_options *opts,
 	int (*callback)(const char *, unsigned int, void *),
 	void *payload);
 
@@ -129,7 +132,10 @@ GIT_EXTERN(int) git_status_foreach_ext(
  *		the file doesn't exist in any of HEAD, the index or the worktree,
  *		GIT_SUCCESS otherwise
  */
-GIT_EXTERN(int) git_status_file(unsigned int *status_flags, git_repository *repo, const char *path);
+GIT_EXTERN(int) git_status_file(
+	unsigned int *status_flags,
+	git_repository *repo,
+	const char *path);
 
 /**
  * Test if the ignore rules apply to a given file.
@@ -141,11 +147,14 @@ GIT_EXTERN(int) git_status_file(unsigned int *status_flags, git_repository *repo
  *
  * @param ignored boolean returning 0 if the file is not ignored, 1 if it is
  * @param repo a repository object
- * @param path the file to check ignores for, rooted at the repo's workdir
- * @return GIT_SUCCESS if the ignore rules could be processed for the file
- *		(regardless of whether it exists or not), or an error < 0 if they could not.
+ * @param path the file to check ignores for, rooted at the repo's workdir.
+ * @return 0 if ignore rules could be processed for the file (regardless
+ *         of whether it exists or not), or an error < 0 if they could not.
  */
-GIT_EXTERN(int) git_status_should_ignore(int *ignored, git_repository *repo, const char *path);
+GIT_EXTERN(int) git_status_should_ignore(
+	int *ignored,
+	git_repository *repo,
+	const char *path);
 
 /** @} */
 GIT_END_DECL
diff --git a/src/attr_file.c b/src/attr_file.c
index 49ff731..5030ad5 100644
--- a/src/attr_file.c
+++ b/src/attr_file.c
@@ -378,7 +378,7 @@ int git_attr_fnmatch__parse(
 				pattern++;
 		}
 		/* remember if we see an unescaped wildcard in pattern */
-		else if ((*scan == '*' || *scan == '.' || *scan == '[') &&
+		else if (git__iswildcard(*scan) &&
 			(scan == pattern || (*(scan - 1) != '\\')))
 			spec->flags = spec->flags | GIT_ATTR_FNMATCH_HASWILD;
 	}
diff --git a/src/buffer.c b/src/buffer.c
index 2ecb088..ef95839 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -415,3 +415,33 @@ int git_buf_cmp(const git_buf *a, const git_buf *b)
 	return (result != 0) ? result :
 		(a->size < b->size) ? -1 : (a->size > b->size) ? 1 : 0;
 }
+
+int git_buf_common_prefix(git_buf *buf, const git_strarray *strings)
+{
+	size_t i;
+	const char *str, *pfx;
+
+	git_buf_clear(buf);
+
+	if (!strings || !strings->count)
+		return 0;
+
+	/* initialize common prefix to first string */
+	if (git_buf_sets(buf, strings->strings[0]) < 0)
+		return -1;
+
+	/* go through the rest of the strings, truncating to shared prefix */
+	for (i = 1; i < strings->count; ++i) {
+
+		for (str = strings->strings[i], pfx = buf->ptr;
+			 *str && *str == *pfx; str++, pfx++)
+			/* scanning */;
+
+		git_buf_truncate(buf, pfx - buf->ptr);
+
+		if (!buf->size)
+			break;
+	}
+
+	return 0;
+}
diff --git a/src/buffer.h b/src/buffer.h
index 1f0ec1c..af760f9 100644
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -122,4 +122,7 @@ void git_buf_rtrim(git_buf *buf);
 
 int git_buf_cmp(const git_buf *a, const git_buf *b);
 
+/* Fill buf with the common prefix of a array of strings */
+int git_buf_common_prefix(git_buf *buf, const git_strarray *strings);
+
 #endif
diff --git a/src/diff.c b/src/diff.c
index fed22f4..c8670b5 100644
--- a/src/diff.c
+++ b/src/diff.c
@@ -11,6 +11,25 @@
 #include "config.h"
 #include "attr_file.h"
 
+static char *diff_prefix_from_pathspec(const git_strarray *pathspec)
+{
+	git_buf prefix = GIT_BUF_INIT;
+	const char *scan;
+
+	if (git_buf_common_prefix(&prefix, pathspec) < 0)
+		return NULL;
+
+	/* diff prefix will only be leading non-wildcards */
+	for (scan = prefix.ptr; *scan && !git__iswildcard(*scan); ++scan);
+	git_buf_truncate(&prefix, scan - prefix.ptr);
+
+	if (prefix.size > 0)
+		return git_buf_detach(&prefix);
+
+	git_buf_free(&prefix);
+	return NULL;
+}
+
 static bool diff_pathspec_is_interesting(const git_strarray *pathspec)
 {
 	const char *str;
@@ -613,13 +632,16 @@ int git_diff_tree_to_tree(
 	git_diff_list **diff)
 {
 	git_iterator *a = NULL, *b = NULL;
+	char *prefix = opts ? diff_prefix_from_pathspec(&opts->pathspec) : NULL;
 
 	assert(repo && old_tree && new_tree && diff);
 
-	if (git_iterator_for_tree(repo, old_tree, &a) < 0 ||
-		git_iterator_for_tree(repo, new_tree, &b) < 0)
+	if (git_iterator_for_tree_range(&a, repo, old_tree, prefix, prefix) < 0 ||
+		git_iterator_for_tree_range(&b, repo, new_tree, prefix, prefix) < 0)
 		return -1;
 
+	git__free(prefix);
+
 	return diff_from_iterators(repo, opts, a, b, diff);
 }
 
@@ -630,13 +652,16 @@ int git_diff_index_to_tree(
 	git_diff_list **diff)
 {
 	git_iterator *a = NULL, *b = NULL;
+	char *prefix = opts ? diff_prefix_from_pathspec(&opts->pathspec) : NULL;
 
 	assert(repo && diff);
 
-	if (git_iterator_for_tree(repo, old_tree, &a) < 0 ||
-		git_iterator_for_index(repo, &b) < 0)
+	if (git_iterator_for_tree_range(&a, repo, old_tree, prefix, prefix) < 0 ||
+		git_iterator_for_index_range(&b, repo, prefix, prefix) < 0)
 		return -1;
 
+	git__free(prefix);
+
 	return diff_from_iterators(repo, opts, a, b, diff);
 }
 
@@ -646,13 +671,16 @@ int git_diff_workdir_to_index(
 	git_diff_list **diff)
 {
 	git_iterator *a = NULL, *b = NULL;
+	char *prefix = opts ? diff_prefix_from_pathspec(&opts->pathspec) : NULL;
 
 	assert(repo && diff);
 
-	if (git_iterator_for_index(repo, &a) < 0 ||
-		git_iterator_for_workdir(repo, &b) < 0)
+	if (git_iterator_for_index_range(&a, repo, prefix, prefix) < 0 ||
+		git_iterator_for_workdir_range(&b, repo, prefix, prefix) < 0)
 		return -1;
 
+	git__free(prefix);
+
 	return diff_from_iterators(repo, opts, a, b, diff);
 }
 
@@ -664,13 +692,16 @@ int git_diff_workdir_to_tree(
 	git_diff_list **diff)
 {
 	git_iterator *a = NULL, *b = NULL;
+	char *prefix = opts ? diff_prefix_from_pathspec(&opts->pathspec) : NULL;
 
 	assert(repo && old_tree && diff);
 
-	if (git_iterator_for_tree(repo, old_tree, &a) < 0 ||
-		git_iterator_for_workdir(repo, &b) < 0)
+	if (git_iterator_for_tree_range(&a, repo, old_tree, prefix, prefix) < 0 ||
+		git_iterator_for_workdir_range(&b, repo, prefix, prefix) < 0)
 		return -1;
 
+	git__free(prefix);
+
 	return diff_from_iterators(repo, opts, a, b, diff);
 }
 
diff --git a/src/index.c b/src/index.c
index 216ede7..8a6ce0f 100644
--- a/src/index.c
+++ b/src/index.c
@@ -502,6 +502,15 @@ int git_index_find(git_index *index, const char *path)
 	return git_vector_bsearch2(&index->entries, index_srch, path);
 }
 
+unsigned int git_index__prefix_position(git_index *index, const char *path)
+{
+	unsigned int pos;
+
+	git_vector_bsearch3(&pos, &index->entries, index_srch, path);
+
+	return pos;
+}
+
 void git_index_uniq(git_index *index)
 {
 	git_vector_uniq(&index->entries);
diff --git a/src/index.h b/src/index.h
index e745c8f..8515f4f 100644
--- a/src/index.h
+++ b/src/index.h
@@ -33,4 +33,6 @@ struct git_index {
 
 extern void git_index__init_entry_from_stat(struct stat *st, git_index_entry *entry);
 
+extern unsigned int git_index__prefix_position(git_index *index, const char *path);
+
 #endif
diff --git a/src/iterator.c b/src/iterator.c
index 646990d..c601a6e 100644
--- a/src/iterator.c
+++ b/src/iterator.c
@@ -11,6 +11,23 @@
 #include "buffer.h"
 #include "git2/submodule.h"
 
+#define ITERATOR_BASE_INIT(P,NAME_LC,NAME_UC) do { \
+	(P) = git__calloc(1, sizeof(NAME_LC ## _iterator)); \
+	GITERR_CHECK_ALLOC(P); \
+	(P)->base.type    = GIT_ITERATOR_ ## NAME_UC; \
+	(P)->base.start   = start ? git__strdup(start) : NULL; \
+	(P)->base.end     = end ? git__strdup(end) : NULL; \
+	(P)->base.current = NAME_LC ## _iterator__current; \
+	(P)->base.at_end  = NAME_LC ## _iterator__at_end; \
+	(P)->base.advance = NAME_LC ## _iterator__advance; \
+	(P)->base.seek    = NAME_LC ## _iterator__seek; \
+	(P)->base.reset   = NAME_LC ## _iterator__reset; \
+	(P)->base.free    = NAME_LC ## _iterator__free; \
+	if ((start && !(P)->base.start) || (end && !(P)->base.end)) \
+		return -1; \
+	} while (0)
+
+
 static int empty_iterator__no_item(
 	git_iterator *iter, const git_index_entry **entry)
 {
@@ -31,6 +48,13 @@ static int empty_iterator__noop(git_iterator *iter)
 	return 0;
 }
 
+static int empty_iterator__seek(git_iterator *iter, const char *prefix)
+{
+	GIT_UNUSED(iter);
+	GIT_UNUSED(prefix);
+	return -1;
+}
+
 static void empty_iterator__free(git_iterator *iter)
 {
 	GIT_UNUSED(iter);
@@ -45,6 +69,7 @@ int git_iterator_for_nothing(git_iterator **iter)
 	i->current = empty_iterator__no_item;
 	i->at_end  = empty_iterator__at_end;
 	i->advance = empty_iterator__no_item;
+	i->seek    = empty_iterator__seek;
 	i->reset   = empty_iterator__noop;
 	i->free    = empty_iterator__free;
 
@@ -53,10 +78,12 @@ int git_iterator_for_nothing(git_iterator **iter)
 	return 0;
 }
 
+
 typedef struct tree_iterator_frame tree_iterator_frame;
 struct tree_iterator_frame {
 	tree_iterator_frame *next;
 	git_tree *tree;
+	char *start;
 	unsigned int index;
 };
 
@@ -66,6 +93,7 @@ typedef struct {
 	tree_iterator_frame *stack;
 	git_index_entry entry;
 	git_buf path;
+	bool path_has_filename;
 } tree_iterator;
 
 static const git_tree_entry *tree_iterator__tree_entry(tree_iterator *ti)
@@ -74,25 +102,62 @@ static const git_tree_entry *tree_iterator__tree_entry(tree_iterator *ti)
 		git_tree_entry_byindex(ti->stack->tree, ti->stack->index);
 }
 
+static char *tree_iterator__current_filename(
+	tree_iterator *ti, const git_tree_entry *te)
+{
+	if (!ti->path_has_filename) {
+		if (git_buf_joinpath(&ti->path, ti->path.ptr, te->filename) < 0)
+			return NULL;
+		ti->path_has_filename = true;
+	}
+
+	return ti->path.ptr;
+}
+
+static void tree_iterator__pop_frame(tree_iterator *ti)
+{
+	tree_iterator_frame *tf = ti->stack;
+	ti->stack = tf->next;
+	if (ti->stack != NULL) /* don't free the initial tree */
+		git_tree_free(tf->tree);
+	git__free(tf);
+}
+
+static int tree_iterator__to_end(tree_iterator *ti)
+{
+	while (ti->stack && ti->stack->next)
+		tree_iterator__pop_frame(ti);
+
+	if (ti->stack)
+		ti->stack->index = git_tree_entrycount(ti->stack->tree);
+
+	return 0;
+}
+
 static int tree_iterator__current(
 	git_iterator *self, const git_index_entry **entry)
 {
 	tree_iterator *ti = (tree_iterator *)self;
 	const git_tree_entry *te = tree_iterator__tree_entry(ti);
 
-	*entry = NULL;
+	if (entry)
+		*entry = NULL;
 
 	if (te == NULL)
 		return 0;
 
 	ti->entry.mode = te->attr;
 	git_oid_cpy(&ti->entry.oid, &te->oid);
-	if (git_buf_joinpath(&ti->path, ti->path.ptr, te->filename) < 0)
+
+	ti->entry.path = tree_iterator__current_filename(ti, te);
+	if (ti->entry.path == NULL)
 		return -1;
 
-	ti->entry.path = ti->path.ptr;
+	if (ti->base.end && git__prefixcmp(ti->entry.path, ti->base.end) > 0)
+		return tree_iterator__to_end(ti);
 
-	*entry = &ti->entry;
+	if (entry)
+		*entry = &ti->entry;
 
 	return 0;
 }
@@ -102,11 +167,20 @@ static int tree_iterator__at_end(git_iterator *self)
 	return (tree_iterator__tree_entry((tree_iterator *)self) == NULL);
 }
 
-static tree_iterator_frame *tree_iterator__alloc_frame(git_tree *tree)
+static tree_iterator_frame *tree_iterator__alloc_frame(
+	git_tree *tree, char *start)
 {
 	tree_iterator_frame *tf = git__calloc(1, sizeof(tree_iterator_frame));
-	if (tf != NULL)
-		tf->tree = tree;
+	if (!tf)
+		return NULL;
+
+	tf->tree = tree;
+
+	if (start && *start) {
+		tf->start = start;
+		tf->index = git_tree_entry_prefix_position(tree, start);
+	}
+
 	return tf;
 }
 
@@ -116,35 +190,43 @@ static int tree_iterator__expand_tree(tree_iterator *ti)
 	git_tree *subtree;
 	const git_tree_entry *te = tree_iterator__tree_entry(ti);
 	tree_iterator_frame *tf;
+	char *relpath;
 
 	while (te != NULL && entry_is_tree(te)) {
+		if (git_buf_joinpath(&ti->path, ti->path.ptr, te->filename) < 0)
+			return -1;
+
+		/* check that we have not passed the range end */
+		if (ti->base.end != NULL &&
+			git__prefixcmp(ti->path.ptr, ti->base.end) > 0)
+			return tree_iterator__to_end(ti);
+
 		if ((error = git_tree_lookup(&subtree, ti->repo, &te->oid)) < 0)
 			return error;
 
-		if ((tf = tree_iterator__alloc_frame(subtree)) == NULL)
+		relpath = NULL;
+
+		/* apply range start to new frame if relevant */
+		if (ti->stack->start &&
+			git__prefixcmp(ti->stack->start, te->filename) == 0)
+		{
+			size_t namelen = strlen(te->filename);
+			if (ti->stack->start[namelen] == '/')
+				relpath = ti->stack->start + namelen + 1;
+		}
+
+		if ((tf = tree_iterator__alloc_frame(subtree, relpath)) == NULL)
 			return -1;
 
 		tf->next  = ti->stack;
 		ti->stack = tf;
 
-		if (git_buf_joinpath(&ti->path, ti->path.ptr, te->filename) < 0)
-			return -1;
-
 		te = tree_iterator__tree_entry(ti);
 	}
 
 	return 0;
 }
 
-static void tree_iterator__pop_frame(tree_iterator *ti)
-{
-	tree_iterator_frame *tf = ti->stack;
-	ti->stack = tf->next;
-	if (ti->stack != NULL) /* don't free the initial tree */
-		git_tree_free(tf->tree);
-	git__free(tf);
-}
-
 static int tree_iterator__advance(
 	git_iterator *self, const git_index_entry **entry)
 {
@@ -155,26 +237,40 @@ static int tree_iterator__advance(
 	if (entry != NULL)
 		*entry = NULL;
 
-	while (ti->stack != NULL) {
-		/* remove old entry filename */
+	if (ti->path_has_filename) {
 		git_buf_rtruncate_at_char(&ti->path, '/');
+		ti->path_has_filename = false;
+	}
 
+	while (ti->stack != NULL) {
 		te = git_tree_entry_byindex(ti->stack->tree, ++ti->stack->index);
 		if (te != NULL)
 			break;
 
 		tree_iterator__pop_frame(ti);
+
+		git_buf_rtruncate_at_char(&ti->path, '/');
 	}
 
 	if (te && entry_is_tree(te))
 		error = tree_iterator__expand_tree(ti);
 
-	if (!error && entry != NULL)
+	if (!error)
 		error = tree_iterator__current(self, entry);
 
 	return error;
 }
 
+static int tree_iterator__seek(git_iterator *self, const char *prefix)
+{
+	GIT_UNUSED(self);
+	GIT_UNUSED(prefix);
+	/* pop stack until matches prefix */
+	/* seek item in current frame matching prefix */
+	/* push stack which matches prefix */
+	return -1;
+}
+
 static void tree_iterator__free(git_iterator *self)
 {
 	tree_iterator *ti = (tree_iterator *)self;
@@ -186,15 +282,25 @@ static void tree_iterator__free(git_iterator *self)
 static int tree_iterator__reset(git_iterator *self)
 {
 	tree_iterator *ti = (tree_iterator *)self;
+
 	while (ti->stack && ti->stack->next)
 		tree_iterator__pop_frame(ti);
+
 	if (ti->stack)
-		ti->stack->index = 0;
+		ti->stack->index =
+			git_tree_entry_prefix_position(ti->stack->tree, ti->base.start);
+
+	git_buf_clear(&ti->path);
+
 	return tree_iterator__expand_tree(ti);
 }
 
-int git_iterator_for_tree(
-	git_repository *repo, git_tree *tree, git_iterator **iter)
+int git_iterator_for_tree_range(
+	git_iterator **iter,
+	git_repository *repo,
+	git_tree *tree,
+	const char *start,
+	const char *end)
 {
 	int error;
 	tree_iterator *ti;
@@ -202,22 +308,16 @@ int git_iterator_for_tree(
 	if (tree == NULL)
 		return git_iterator_for_nothing(iter);
 
-	ti = git__calloc(1, sizeof(tree_iterator));
-	GITERR_CHECK_ALLOC(ti);
+	ITERATOR_BASE_INIT(ti, tree, TREE);
 
-	ti->base.type    = GIT_ITERATOR_TREE;
-	ti->base.current = tree_iterator__current;
-	ti->base.at_end  = tree_iterator__at_end;
-	ti->base.advance = tree_iterator__advance;
-	ti->base.reset   = tree_iterator__reset;
-	ti->base.free    = tree_iterator__free;
-	ti->repo         = repo;
-	ti->stack        = tree_iterator__alloc_frame(tree);
+	ti->repo  = repo;
+	ti->stack = tree_iterator__alloc_frame(tree, ti->base.start);
 
 	if ((error = tree_iterator__expand_tree(ti)) < 0)
 		git_iterator_free((git_iterator *)ti);
 	else
 		*iter = (git_iterator *)ti;
+
 	return error;
 }
 
@@ -232,7 +332,19 @@ static int index_iterator__current(
 	git_iterator *self, const git_index_entry **entry)
 {
 	index_iterator *ii = (index_iterator *)self;
-	*entry = git_index_get(ii->index, ii->current);
+	git_index_entry *ie = git_index_get(ii->index, ii->current);
+
+	if (ie != NULL &&
+		ii->base.end != NULL &&
+		git__prefixcmp(ie->path, ii->base.end) > 0)
+	{
+		ii->current = git_index_entrycount(ii->index);
+		ie = NULL;
+	}
+
+	if (entry)
+		*entry = ie;
+
 	return 0;
 }
 
@@ -246,11 +358,19 @@ static int index_iterator__advance(
 	git_iterator *self, const git_index_entry **entry)
 {
 	index_iterator *ii = (index_iterator *)self;
+
 	if (ii->current < git_index_entrycount(ii->index))
 		ii->current++;
-	if (entry)
-		*entry = git_index_get(ii->index, ii->current);
-	return 0;
+
+	return index_iterator__current(self, entry);
+}
+
+static int index_iterator__seek(git_iterator *self, const char *prefix)
+{
+	GIT_UNUSED(self);
+	GIT_UNUSED(prefix);
+	/* find last item before prefix */
+	return -1;
 }
 
 static int index_iterator__reset(git_iterator *self)
@@ -267,24 +387,24 @@ static void index_iterator__free(git_iterator *self)
 	ii->index = NULL;
 }
 
-int git_iterator_for_index(git_repository *repo, git_iterator **iter)
+int git_iterator_for_index_range(
+	git_iterator **iter,
+	git_repository *repo,
+	const char *start,
+	const char *end)
 {
 	int error;
-	index_iterator *ii = git__calloc(1, sizeof(index_iterator));
-	GITERR_CHECK_ALLOC(ii);
+	index_iterator *ii;
 
-	ii->base.type    = GIT_ITERATOR_INDEX;
-	ii->base.current = index_iterator__current;
-	ii->base.at_end  = index_iterator__at_end;
-	ii->base.advance = index_iterator__advance;
-	ii->base.reset   = index_iterator__reset;
-	ii->base.free    = index_iterator__free;
-	ii->current      = 0;
+	ITERATOR_BASE_INIT(ii, index, INDEX);
 
 	if ((error = git_repository_index(&ii->index, repo)) < 0)
 		git__free(ii);
-	else
+	else {
+		ii->current = start ? git_index__prefix_position(ii->index, start) : 0;
 		*iter = (git_iterator *)ii;
+	}
+
 	return error;
 }
 
@@ -294,6 +414,7 @@ struct workdir_iterator_frame {
 	workdir_iterator_frame *next;
 	git_vector entries;
 	unsigned int index;
+	char *start;
 };
 
 typedef struct {
@@ -332,6 +453,12 @@ static void workdir_iterator__free_frame(workdir_iterator_frame *wf)
 
 static int workdir_iterator__update_entry(workdir_iterator *wi);
 
+static int workdir_iterator__entry_cmp(const void *prefix, const void *item)
+{
+	const git_path_with_stat *ps = item;
+	return git__prefixcmp((const char *)prefix, ps->path);
+}
+
 static int workdir_iterator__expand_dir(workdir_iterator *wi)
 {
 	int error;
@@ -345,6 +472,17 @@ static int workdir_iterator__expand_dir(workdir_iterator *wi)
 	}
 
 	git_vector_sort(&wf->entries);
+
+	if (!wi->stack)
+		wf->start = wi->base.start;
+	else if (wi->stack->start &&
+		git__prefixcmp(wi->stack->start, wi->path.ptr + wi->root_len) == 0)
+		wf->start = wi->stack->start;
+
+	if (wf->start)
+		git_vector_bsearch3(
+			&wf->index, &wf->entries, workdir_iterator__entry_cmp, wf->start);
+
 	wf->next  = wi->stack;
 	wi->stack = wf;
 
@@ -412,6 +550,16 @@ static int workdir_iterator__advance(
 	return error;
 }
 
+static int workdir_iterator__seek(git_iterator *self, const char *prefix)
+{
+	GIT_UNUSED(self);
+	GIT_UNUSED(prefix);
+	/* pop stack until matching prefix */
+	/* find prefix item in current frame */
+	/* push subdirectories as deep as possible while matching */
+	return 0;
+}
+
 static int workdir_iterator__reset(git_iterator *self)
 {
 	workdir_iterator *wi = (workdir_iterator *)self;
@@ -445,10 +593,18 @@ static int workdir_iterator__update_entry(workdir_iterator *wi)
 	git_path_with_stat *ps = git_vector_get(&wi->stack->entries, wi->stack->index);
 
 	git_buf_truncate(&wi->path, wi->root_len);
+	memset(&wi->entry, 0, sizeof(wi->entry));
+
+	if (!ps)
+		return 0;
+
 	if (git_buf_put(&wi->path, ps->path, ps->path_len) < 0)
 		return -1;
 
-	memset(&wi->entry, 0, sizeof(wi->entry));
+	if (wi->base.end &&
+		git__prefixcmp(wi->path.ptr + wi->root_len, wi->base.end) > 0)
+		return 0;
+
 	wi->entry.path = ps->path;
 
 	/* skip over .git directory */
@@ -495,19 +651,24 @@ static int workdir_iterator__update_entry(workdir_iterator *wi)
 	return 0;
 }
 
-int git_iterator_for_workdir(git_repository *repo, git_iterator **iter)
+int git_iterator_for_workdir_range(
+	git_iterator **iter,
+	git_repository *repo,
+	const char *start,
+	const char *end)
 {
 	int error;
-	workdir_iterator *wi = git__calloc(1, sizeof(workdir_iterator));
-	GITERR_CHECK_ALLOC(wi);
+	workdir_iterator *wi;
 
-	wi->base.type    = GIT_ITERATOR_WORKDIR;
-	wi->base.current = workdir_iterator__current;
-	wi->base.at_end  = workdir_iterator__at_end;
-	wi->base.advance = workdir_iterator__advance;
-	wi->base.reset   = workdir_iterator__reset;
-	wi->base.free    = workdir_iterator__free;
-	wi->repo         = repo;
+	if (git_repository_is_bare(repo)) {
+		giterr_set(GITERR_INVALID,
+			"Cannot scan working directory for bare repo");
+		return -1;
+	}
+
+	ITERATOR_BASE_INIT(wi, workdir, WORKDIR);
+
+	wi->repo = repo;
 
 	if (git_buf_sets(&wi->path, git_repository_workdir(repo)) < 0 ||
 		git_path_to_dir(&wi->path) < 0 ||
@@ -559,3 +720,21 @@ int git_iterator_advance_into_directory(
 
 	return entry ? git_iterator_current(iter, entry) : 0;
 }
+
+int git_iterator_cmp(
+	git_iterator *iter, const char *path_prefix)
+{
+	const git_index_entry *entry;
+
+	/* a "done" iterator is after every prefix */
+	if (git_iterator_current(iter, &entry) < 0 ||
+		entry == NULL)
+		return 1;
+
+	/* a NULL prefix is after any valid iterator */
+	if (!path_prefix)
+		return -1;
+
+	return git__prefixcmp(entry->path, path_prefix);
+}
+
diff --git a/src/iterator.h b/src/iterator.h
index 974c2da..b916a90 100644
--- a/src/iterator.h
+++ b/src/iterator.h
@@ -21,23 +21,48 @@ typedef enum {
 
 struct git_iterator {
 	git_iterator_type_t type;
+	char *start;
+	char *end;
 	int (*current)(git_iterator *, const git_index_entry **);
 	int (*at_end)(git_iterator *);
 	int (*advance)(git_iterator *, const git_index_entry **);
+	int (*seek)(git_iterator *, const char *prefix);
 	int (*reset)(git_iterator *);
 	void (*free)(git_iterator *);
 };
 
-int git_iterator_for_nothing(git_iterator **iter);
+extern int git_iterator_for_nothing(git_iterator **iter);
 
-int git_iterator_for_tree(
-	git_repository *repo, git_tree *tree, git_iterator **iter);
+extern int git_iterator_for_tree_range(
+	git_iterator **iter, git_repository *repo, git_tree *tree,
+	const char *start, const char *end);
 
-int git_iterator_for_index(
-	git_repository *repo, git_iterator **iter);
+GIT_INLINE(int) git_iterator_for_tree(
+	git_iterator **iter, git_repository *repo, git_tree *tree)
+{
+	return git_iterator_for_tree_range(iter, repo, tree, NULL, NULL);
+}
+
+extern int git_iterator_for_index_range(
+	git_iterator **iter, git_repository *repo,
+	const char *start, const char *end);
+
+GIT_INLINE(int) git_iterator_for_index(
+	git_iterator **iter, git_repository *repo)
+{
+	return git_iterator_for_index_range(iter, repo, NULL, NULL);
+}
+
+extern int git_iterator_for_workdir_range(
+	git_iterator **iter, git_repository *repo,
+	const char *start, const char *end);
+
+GIT_INLINE(int) git_iterator_for_workdir(
+	git_iterator **iter, git_repository *repo)
+{
+	return git_iterator_for_workdir_range(iter, repo, NULL, NULL);
+}
 
-int git_iterator_for_workdir(
-	git_repository *repo, git_iterator **iter);
 
 /* Entry is not guaranteed to be fully populated.  For a tree iterator,
  * we will only populate the mode, oid and path, for example.  For a workdir
@@ -64,6 +89,12 @@ GIT_INLINE(int) git_iterator_advance(
 	return iter->advance(iter, entry);
 }
 
+GIT_INLINE(int) git_iterator_seek(
+	git_iterator *iter, const char *prefix)
+{
+	return iter->seek(iter, prefix);
+}
+
 GIT_INLINE(int) git_iterator_reset(git_iterator *iter)
 {
 	return iter->reset(iter);
@@ -75,6 +106,12 @@ GIT_INLINE(void) git_iterator_free(git_iterator *iter)
 		return;
 
 	iter->free(iter);
+
+	git__free(iter->start);
+	git__free(iter->end);
+
+	memset(iter, 0, sizeof(*iter));
+
 	git__free(iter);
 }
 
@@ -108,4 +145,7 @@ extern int git_iterator_current_is_ignored(git_iterator *iter);
 extern int git_iterator_advance_into_directory(
 	git_iterator *iter, const git_index_entry **entry);
 
+extern int git_iterator_cmp(
+	git_iterator *iter, const char *path_prefix);
+
 #endif
diff --git a/src/notes.c b/src/notes.c
index e14ab93..1da2ac4 100644
--- a/src/notes.c
+++ b/src/notes.c
@@ -523,7 +523,7 @@ int git_note_foreach(
 	if (git_tree_lookup(&tree, repo, &tree_oid) < 0)
 		goto cleanup;
 
-	if (git_iterator_for_tree(repo, tree, &iter) < 0)
+	if (git_iterator_for_tree(&iter, repo, tree) < 0)
 		goto cleanup;
 
 	if (git_iterator_current(iter, &item) < 0)
diff --git a/src/status.c b/src/status.c
index 1c5609c..e9ad3cf 100644
--- a/src/status.c
+++ b/src/status.c
@@ -70,7 +70,7 @@ static unsigned int workdir_delta2status(git_delta_t workdir_status)
 
 int git_status_foreach_ext(
 	git_repository *repo,
-	git_status_options *opts,
+	const git_status_options *opts,
 	int (*cb)(const char *, unsigned int, void *),
 	void *cbdata)
 {
@@ -163,245 +163,71 @@ int git_status_foreach(
 	return git_status_foreach_ext(repo, &opts, callback, payload);
 }
 
-
-/*
- * the old stuff
- */
-
-struct status_entry {
-	git_index_time mtime;
-
-	git_oid head_oid;
-	git_oid index_oid;
-	git_oid wt_oid;
-
-	unsigned int status_flags;
-
-	char path[GIT_FLEX_ARRAY]; /* more */
+struct status_file_info {
+	unsigned int count;
+	unsigned int status;
+	char *expected;
 };
 
-static struct status_entry *status_entry_new(git_vector *entries, const char *path)
-{
-	struct status_entry *e = git__calloc(sizeof(*e) + strlen(path) + 1, 1);
-	if (e == NULL)
-		return NULL;
-
-	if (entries != NULL)
-		git_vector_insert(entries, e);
-
-	strcpy(e->path, path);
-
-	return e;
-}
-
-GIT_INLINE(void) status_entry_update_from_tree_entry(struct status_entry *e, const git_tree_entry *tree_entry)
-{
-	assert(e && tree_entry);
-
-	git_oid_cpy(&e->head_oid, &tree_entry->oid);
-}
-
-GIT_INLINE(void) status_entry_update_from_index_entry(struct status_entry *e, const git_index_entry *index_entry)
-{
-	assert(e && index_entry);
-
-	git_oid_cpy(&e->index_oid, &index_entry->oid);
-	e->mtime = index_entry->mtime;
-}
-
-static void status_entry_update_from_index(struct status_entry *e, git_index *index)
-{
-	int idx;
-	git_index_entry *index_entry;
-
-	assert(e && index);
-
-	idx = git_index_find(index, e->path);
-	if (idx < 0)
-		return;
-
-	index_entry = git_index_get(index, idx);
-
-	status_entry_update_from_index_entry(e, index_entry);
-}
-
-static int status_entry_update_from_workdir(struct status_entry *e, const char* full_path)
-{
-	struct stat filest;
-
-	if (p_stat(full_path, &filest) < 0) {
-		giterr_set(GITERR_OS, "Cannot access file '%s'", full_path);
-		return GIT_ENOTFOUND;
-	}
-
-	if (e->mtime.seconds == (git_time_t)filest.st_mtime)
-		git_oid_cpy(&e->wt_oid, &e->index_oid);
-	else
-		git_odb_hashfile(&e->wt_oid, full_path, GIT_OBJ_BLOB);
-
-	return 0;
-}
-
-static int status_entry_update_flags(struct status_entry *e)
-{
-	git_oid zero;
-	int head_zero, index_zero, wt_zero;
-
-	memset(&zero, 0x0, sizeof(git_oid));
-
-	head_zero = git_oid_cmp(&zero, &e->head_oid);
-	index_zero = git_oid_cmp(&zero, &e->index_oid);
-	wt_zero = git_oid_cmp(&zero, &e->wt_oid);
-
-	if (head_zero == 0 && index_zero == 0 && wt_zero == 0)
-		return GIT_ENOTFOUND;
-
-	if (head_zero == 0 && index_zero != 0)
-		e->status_flags |= GIT_STATUS_INDEX_NEW;
-	else if (index_zero == 0 && head_zero != 0)
-		e->status_flags |= GIT_STATUS_INDEX_DELETED;
-	else if (git_oid_cmp(&e->head_oid, &e->index_oid) != 0)
-		e->status_flags |= GIT_STATUS_INDEX_MODIFIED;
-
-	if (index_zero == 0 && wt_zero != 0)
-		e->status_flags |= GIT_STATUS_WT_NEW;
-	else if (wt_zero == 0 && index_zero != 0)
-		e->status_flags |= GIT_STATUS_WT_DELETED;
-	else if (git_oid_cmp(&e->index_oid, &e->wt_oid) != 0)
-		e->status_flags |= GIT_STATUS_WT_MODIFIED;
-
-	return 0;
-}
-
-static int status_entry_is_ignorable(struct status_entry *e)
+static int get_one_status(const char *path, unsigned int status, void *data)
 {
-	/* don't ignore files that exist in head or index already */
-	return (e->status_flags == GIT_STATUS_WT_NEW);
-}
+	struct status_file_info *sfi = data;
 
-static int status_entry_update_ignore(struct status_entry *e, git_ignores *ignores, const char *path)
-{
-	int ignored;
+	sfi->count++;
+	sfi->status = status;
 
-	if (git_ignore__lookup(ignores, path, &ignored) < 0)
+	if (sfi->count > 1 || strcmp(sfi->expected, path) != 0) {
+		giterr_set(GITERR_INVALID,
+			"Ambiguous path '%s' given to git_status_file", sfi->expected);
 		return -1;
-
-	if (ignored)
-		/* toggle off WT_NEW and on IGNORED */
-		e->status_flags =
-			(e->status_flags & ~GIT_STATUS_WT_NEW) | GIT_STATUS_IGNORED;
-
-	return 0;
-}
-
-static int recurse_tree_entry(git_tree *tree, struct status_entry *e, const char *path)
-{
-	char *dir_sep;
-	const git_tree_entry *tree_entry;
-	git_tree *subtree;
-	int error;
-
-	dir_sep = strchr(path, '/');
-	if (!dir_sep) {
-		if ((tree_entry = git_tree_entry_byname(tree, path)) != NULL)
-			/* The leaf exists in the tree*/
-			status_entry_update_from_tree_entry(e, tree_entry);
-		return 0;
-	}
-
-	/* Retrieve subtree name */
-	*dir_sep = '\0';
-
-	if ((tree_entry = git_tree_entry_byname(tree, path)) == NULL)
-		return 0; /* The subtree doesn't exist in the tree*/
-
-	*dir_sep = '/';
-
-	/* Retreive subtree */
-	error = git_tree_lookup(&subtree, tree->object.repo, &tree_entry->oid);
-	if (!error) {
-		error = recurse_tree_entry(subtree, e, dir_sep+1);
-		git_tree_free(subtree);
 	}
 
-	return error;
+	return 0;
 }
 
 int git_status_file(
-	unsigned int *status_flags, git_repository *repo, const char *path)
+	unsigned int *status_flags,
+	git_repository *repo,
+	const char *path)
 {
-	struct status_entry *e;
-	git_index *index = NULL;
-	git_buf temp_path = GIT_BUF_INIT;
-	int error = 0;
-	git_tree *tree = NULL;
-	const char *workdir;
+	int error;
+	git_status_options opts;
+	struct status_file_info sfi;
 
 	assert(status_flags && repo && path);
 
-	if ((workdir = git_repository_workdir(repo)) == NULL) {
-		giterr_set(GITERR_INVALID, "Cannot get file status from bare repo");
+	memset(&sfi, 0, sizeof(sfi));
+	if ((sfi.expected = git__strdup(path)) == NULL)
 		return -1;
-	}
-
-	if (git_buf_joinpath(&temp_path, workdir, path) < 0)
-		return -1;
-
-	if (git_path_isdir(temp_path.ptr)) {
-		giterr_set(GITERR_INVALID, "Cannot get file status for directory '%s'", temp_path.ptr);
-		git_buf_free(&temp_path);
-		return -1;
-	}
-
-	e = status_entry_new(NULL, path);
-	GITERR_CHECK_ALLOC(e);
-
-	/* Find file in Workdir */
-	if (git_path_exists(temp_path.ptr) == true &&
-		(error = status_entry_update_from_workdir(e, temp_path.ptr)) < 0)
-		goto cleanup;
-
-	/* Find file in Index */
-	if ((error = git_repository_index__weakptr(&index, repo)) < 0)
-		goto cleanup;
-	status_entry_update_from_index(e, index);
 
-	/* Try to find file in HEAD */
-	if ((error = git_repository_head_tree(&tree, repo)) < 0)
-		goto cleanup;
-
-	if (tree != NULL) {
-		if ((error = git_buf_sets(&temp_path, path)) < 0 ||
-			(error = recurse_tree_entry(tree, e, temp_path.ptr)) < 0)
-			goto cleanup;
-	}
-
-	/* Determine status */
-	if ((error = status_entry_update_flags(e)) < 0)
-		giterr_set(GITERR_OS, "Cannot find file '%s' to determine status", path);
-
-	if (!error && status_entry_is_ignorable(e)) {
-		git_ignores ignores;
+	memset(&opts, 0, sizeof(opts));
+	opts.show  = GIT_STATUS_SHOW_INDEX_AND_WORKDIR;
+	opts.flags = GIT_STATUS_OPT_INCLUDE_IGNORED |
+		GIT_STATUS_OPT_INCLUDE_UNTRACKED |
+		GIT_STATUS_OPT_RECURSE_UNTRACKED_DIRS |
+		GIT_STATUS_OPT_INCLUDE_UNMODIFIED;
+	opts.pathspec.count = 1;
+	opts.pathspec.strings = &sfi.expected;
 
-		if ((error = git_ignore__for_path(repo, path, &ignores)) == 0)
-			error = status_entry_update_ignore(e, &ignores, path);
+	error = git_status_foreach_ext(repo, &opts, get_one_status, &sfi);
 
-		git_ignore__free(&ignores);
+	if (!error && !sfi.count) {
+		giterr_set(GITERR_INVALID,
+			"Attempt to get status of nonexistent file '%s'", path);
+		error = GIT_ENOTFOUND;
 	}
 
-	if (!error)
-		*status_flags = e->status_flags;
+	*status_flags = sfi.status;
 
-cleanup:
-	git_buf_free(&temp_path);
-	git_tree_free(tree);
-	git__free(e);
+	git__free(sfi.expected);
 
 	return error;
 }
 
 int git_status_should_ignore(
-	int *ignored, git_repository *repo, const char *path)
+	int *ignored,
+	git_repository *repo,
+	const char *path)
 {
 	int error;
 	git_ignores ignores;
diff --git a/src/tree.c b/src/tree.c
index 7e2bfc1..adbf974 100644
--- a/src/tree.c
+++ b/src/tree.c
@@ -195,6 +195,33 @@ const git_tree_entry *git_tree_entry_byindex(git_tree *tree, unsigned int idx)
 	return git_vector_get(&tree->entries, idx);
 }
 
+int git_tree_entry_prefix_position(git_tree *tree, const char *path)
+{
+	git_vector *entries = &tree->entries;
+	struct tree_key_search ksearch;
+	unsigned int at_pos;
+
+	ksearch.filename = path;
+	ksearch.filename_len = strlen(path);
+
+	/* Find tree entry with appropriate prefix */
+	git_vector_bsearch3(&at_pos, entries, &homing_search_cmp, &ksearch);
+
+	for (; at_pos < entries->length; ++at_pos) {
+		const git_tree_entry *entry = entries->contents[at_pos];
+		if (homing_search_cmp(&ksearch, entry) < 0)
+			break;
+	}
+
+	for (; at_pos > 0; --at_pos) {
+		const git_tree_entry *entry = entries->contents[at_pos - 1];
+		if (homing_search_cmp(&ksearch, entry) > 0)
+			break;
+	}
+
+	return at_pos;
+}
+
 unsigned int git_tree_entrycount(git_tree *tree)
 {
 	assert(tree);
diff --git a/src/tree.h b/src/tree.h
index fd00afd..a5b7f63 100644
--- a/src/tree.h
+++ b/src/tree.h
@@ -38,4 +38,14 @@ GIT_INLINE(unsigned int) entry_is_tree(const struct git_tree_entry *e)
 void git_tree__free(git_tree *tree);
 int git_tree__parse(git_tree *tree, git_odb_object *obj);
 
+/**
+ * Lookup the first position in the tree with a given prefix.
+ *
+ * @param tree a previously loaded tree.
+ * @param prefix the beginning of a path to find in the tree.
+ * @return index of the first item at or after the given prefix.
+ */
+int git_tree_entry_prefix_position(git_tree *tree, const char *prefix);
+
+
 #endif
diff --git a/src/util.h b/src/util.h
index 2081f29..cb5e83c 100644
--- a/src/util.h
+++ b/src/util.h
@@ -209,4 +209,9 @@ GIT_INLINE(bool) git__isspace(int c)
     return (c == ' ' || c == '\t' || c == '\n' || c == '\f' || c == '\r' || c == '\v');
 }
 
+GIT_INLINE(bool) git__iswildcard(int c)
+{
+	return (c == '*' || c == '?' || c == '[');
+}
+
 #endif /* INCLUDE_util_h__ */
diff --git a/src/vector.c b/src/vector.c
index 304f324..6f9aacc 100644
--- a/src/vector.c
+++ b/src/vector.c
@@ -116,8 +116,13 @@ void git_vector_sort(git_vector *v)
 	v->sorted = 1;
 }
 
-int git_vector_bsearch2(git_vector *v, git_vector_cmp key_lookup, const void *key)
+int git_vector_bsearch3(
+	unsigned int *at_pos,
+	git_vector *v,
+	git_vector_cmp key_lookup,
+	const void *key)
 {
+	int rval;
 	size_t pos;
 
 	assert(v && key && key_lookup);
@@ -127,13 +132,16 @@ int git_vector_bsearch2(git_vector *v, git_vector_cmp key_lookup, const void *ke
 
 	git_vector_sort(v);
 
-	if (git__bsearch(v->contents, v->length, key, key_lookup, &pos) >= 0)
-		return (int)pos;
+	rval = git__bsearch(v->contents, v->length, key, key_lookup, &pos);
 
-	return GIT_ENOTFOUND;
+	if (at_pos != NULL)
+		*at_pos = (unsigned int)pos;
+
+	return (rval >= 0) ? (int)pos : GIT_ENOTFOUND;
 }
 
-int git_vector_search2(git_vector *v, git_vector_cmp key_lookup, const void *key)
+int git_vector_search2(
+	git_vector *v, git_vector_cmp key_lookup, const void *key)
 {
 	unsigned int i;
 
@@ -157,11 +165,6 @@ 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;
diff --git a/src/vector.h b/src/vector.h
index 5bc2791..9139db3 100644
--- a/src/vector.h
+++ b/src/vector.h
@@ -26,13 +26,24 @@ void git_vector_free(git_vector *v);
 void git_vector_clear(git_vector *v);
 void git_vector_swap(git_vector *a, git_vector *b);
 
+void git_vector_sort(git_vector *v);
+
 int git_vector_search(git_vector *v, const void *entry);
 int git_vector_search2(git_vector *v, git_vector_cmp cmp, const void *key);
 
-int git_vector_bsearch(git_vector *v, const void *entry);
-int git_vector_bsearch2(git_vector *v, git_vector_cmp cmp, const void *key);
+int git_vector_bsearch3(
+	unsigned int *at_pos, git_vector *v, git_vector_cmp cmp, const void *key);
 
-void git_vector_sort(git_vector *v);
+GIT_INLINE(int) git_vector_bsearch(git_vector *v, const void *key)
+{
+	return git_vector_bsearch3(NULL, v, v->_cmp, key);
+}
+
+GIT_INLINE(int) git_vector_bsearch2(
+	git_vector *v, git_vector_cmp cmp, const void *key)
+{
+	return git_vector_bsearch3(NULL, v, cmp, key);
+}
 
 GIT_INLINE(void *) git_vector_get(git_vector *v, unsigned int position)
 {
diff --git a/tests-clar/core/buffer.c b/tests-clar/core/buffer.c
index 9294ccd..6a718f4 100644
--- a/tests-clar/core/buffer.c
+++ b/tests-clar/core/buffer.c
@@ -561,3 +561,53 @@ void test_core_buffer__10(void)
 
 	git_buf_free(&a);
 }
+
+void test_core_buffer__11(void)
+{
+	git_buf a = GIT_BUF_INIT;
+	git_strarray t;
+	char *t1[] = { "nothing", "in", "common" };
+	char *t2[] = { "something", "something else", "some other" };
+	char *t3[] = { "something", "some fun", "no fun" };
+	char *t4[] = { "happy", "happier", "happiest" };
+	char *t5[] = { "happiest", "happier", "happy" };
+	char *t6[] = { "no", "nope", "" };
+	char *t7[] = { "", "doesn't matter" };
+
+	t.strings = t1;
+	t.count = 3;
+	cl_git_pass(git_buf_common_prefix(&a, &t));
+	cl_assert_equal_s(a.ptr, "");
+
+	t.strings = t2;
+	t.count = 3;
+	cl_git_pass(git_buf_common_prefix(&a, &t));
+	cl_assert_equal_s(a.ptr, "some");
+
+	t.strings = t3;
+	t.count = 3;
+	cl_git_pass(git_buf_common_prefix(&a, &t));
+	cl_assert_equal_s(a.ptr, "");
+
+	t.strings = t4;
+	t.count = 3;
+	cl_git_pass(git_buf_common_prefix(&a, &t));
+	cl_assert_equal_s(a.ptr, "happ");
+
+	t.strings = t5;
+	t.count = 3;
+	cl_git_pass(git_buf_common_prefix(&a, &t));
+	cl_assert_equal_s(a.ptr, "happ");
+
+	t.strings = t6;
+	t.count = 3;
+	cl_git_pass(git_buf_common_prefix(&a, &t));
+	cl_assert_equal_s(a.ptr, "");
+
+	t.strings = t7;
+	t.count = 3;
+	cl_git_pass(git_buf_common_prefix(&a, &t));
+	cl_assert_equal_s(a.ptr, "");
+
+	git_buf_free(&a);
+}
diff --git a/tests-clar/diff/iterator.c b/tests-clar/diff/iterator.c
index 0ec2326..be29bea 100644
--- a/tests-clar/diff/iterator.c
+++ b/tests-clar/diff/iterator.c
@@ -22,6 +22,8 @@ void test_diff_iterator__cleanup(void)
 static void tree_iterator_test(
 	const char *sandbox,
 	const char *treeish,
+	const char *start,
+	const char *end,
 	int expected_count,
 	const char **expected_values)
 {
@@ -32,7 +34,7 @@ static void tree_iterator_test(
 	git_repository *repo = cl_git_sandbox_init(sandbox);
 
 	cl_assert(t = resolve_commit_oid_to_tree(repo, treeish));
-	cl_git_pass(git_iterator_for_tree(repo, t, &i));
+	cl_git_pass(git_iterator_for_tree_range(&i, repo, t, start, end));
 	cl_git_pass(git_iterator_current(i, &entry));
 
 	while (entry != NULL) {
@@ -74,7 +76,7 @@ const char *expected_tree_0[] = {
 
 void test_diff_iterator__tree_0(void)
 {
-	tree_iterator_test("attr", "605812a", 16, expected_tree_0);
+	tree_iterator_test("attr", "605812a", NULL, NULL, 16, expected_tree_0);
 }
 
 /* results of: git ls-tree -r --name-only 6bab5c79 */
@@ -97,7 +99,7 @@ const char *expected_tree_1[] = {
 
 void test_diff_iterator__tree_1(void)
 {
-	tree_iterator_test("attr", "6bab5c79cd5", 13, expected_tree_1);
+	tree_iterator_test("attr", "6bab5c79cd5", NULL, NULL, 13, expected_tree_1);
 }
 
 /* results of: git ls-tree -r --name-only 26a125ee1 */
@@ -119,7 +121,7 @@ const char *expected_tree_2[] = {
 
 void test_diff_iterator__tree_2(void)
 {
-	tree_iterator_test("status", "26a125ee1", 12, expected_tree_2);
+	tree_iterator_test("status", "26a125ee1", NULL, NULL, 12, expected_tree_2);
 }
 
 /* $ git ls-tree -r --name-only 0017bd4ab1e */
@@ -136,7 +138,7 @@ const char *expected_tree_3[] = {
 
 void test_diff_iterator__tree_3(void)
 {
-	tree_iterator_test("status", "0017bd4ab1e", 8, expected_tree_3);
+	tree_iterator_test("status", "0017bd4ab1e", NULL, NULL, 8, expected_tree_3);
 }
 
 /* $ git ls-tree -r --name-only 24fa9a9fc4e202313e24b648087495441dab432b */
@@ -170,14 +172,77 @@ const char *expected_tree_4[] = {
 void test_diff_iterator__tree_4(void)
 {
 	tree_iterator_test(
-		"attr", "24fa9a9fc4e202313e24b648087495441dab432b",
+		"attr", "24fa9a9fc4e202313e24b648087495441dab432b", NULL, NULL,
 		23, expected_tree_4);
 }
 
+void test_diff_iterator__tree_4_ranged(void)
+{
+	tree_iterator_test(
+		"attr", "24fa9a9fc4e202313e24b648087495441dab432b",
+		"sub", "sub",
+		11, &expected_tree_4[12]);
+}
+
+const char *expected_tree_ranged_0[] = {
+	"gitattributes",
+	"macro_bad",
+	"macro_test",
+	"root_test1",
+	"root_test2",
+	"root_test3",
+	"root_test4.txt",
+	NULL
+};
+
+void test_diff_iterator__tree_ranged_0(void)
+{
+	tree_iterator_test(
+		"attr", "24fa9a9fc4e202313e24b648087495441dab432b",
+		"git", "root",
+		7, expected_tree_ranged_0);
+}
+
+const char *expected_tree_ranged_1[] = {
+	"sub/subdir_test2.txt",
+	NULL
+};
+
+void test_diff_iterator__tree_ranged_1(void)
+{
+	tree_iterator_test(
+		"attr", "24fa9a9fc4e202313e24b648087495441dab432b",
+		"sub/subdir_test2.txt", "sub/subdir_test2.txt",
+		1, expected_tree_ranged_1);
+}
+
+void test_diff_iterator__tree_range_empty_0(void)
+{
+	tree_iterator_test(
+		"attr", "24fa9a9fc4e202313e24b648087495441dab432b",
+		"empty", "empty", 0, NULL);
+}
+
+void test_diff_iterator__tree_range_empty_1(void)
+{
+	tree_iterator_test(
+		"attr", "24fa9a9fc4e202313e24b648087495441dab432b",
+		"z_empty_after", NULL, 0, NULL);
+}
+
+void test_diff_iterator__tree_range_empty_2(void)
+{
+	tree_iterator_test(
+		"attr", "24fa9a9fc4e202313e24b648087495441dab432b",
+		NULL, ".aaa_empty_before", 0, NULL);
+}
+
 /* -- INDEX ITERATOR TESTS -- */
 
 static void index_iterator_test(
 	const char *sandbox,
+	const char *start,
+	const char *end,
 	int expected_count,
 	const char **expected_names,
 	const char **expected_oids)
@@ -187,7 +252,7 @@ static void index_iterator_test(
 	int count = 0;
 	git_repository *repo = cl_git_sandbox_init(sandbox);
 
-	cl_git_pass(git_iterator_for_index(repo, &i));
+	cl_git_pass(git_iterator_for_index_range(&i, repo, start, end));
 	cl_git_pass(git_iterator_current(i, &entry));
 
 	while (entry != NULL) {
@@ -197,7 +262,7 @@ static void index_iterator_test(
 		if (expected_oids != NULL) {
 			git_oid oid;
 			cl_git_pass(git_oid_fromstr(&oid, expected_oids[count]));
-			cl_assert(git_oid_cmp(&oid, &entry->oid) == 0);
+			cl_assert_equal_i(git_oid_cmp(&oid, &entry->oid), 0);
 		}
 
 		count++;
@@ -206,7 +271,7 @@ static void index_iterator_test(
 
 	git_iterator_free(i);
 
-	cl_assert(count == expected_count);
+	cl_assert_equal_i(expected_count, count);
 }
 
 static const char *expected_index_0[] = {
@@ -263,7 +328,46 @@ static const char *expected_index_oids_0[] = {
 
 void test_diff_iterator__index_0(void)
 {
-	index_iterator_test("attr", 23, expected_index_0, expected_index_oids_0);
+	index_iterator_test(
+		"attr", NULL, NULL, 23, expected_index_0, expected_index_oids_0);
+}
+
+static const char *expected_index_range[] = {
+	"root_test1",
+	"root_test2",
+	"root_test3",
+	"root_test4.txt",
+};
+
+static const char *expected_index_oids_range[] = {
+	"45141a79a77842c59a63229403220a4e4be74e3d",
+	"4d713dc48e6b1bd75b0d61ad078ba9ca3a56745d",
+	"108bb4e7fd7b16490dc33ff7d972151e73d7166e",
+	"fe773770c5a6cc7185580c9204b1ff18a33ff3fc",
+};
+
+void test_diff_iterator__index_range(void)
+{
+	index_iterator_test(
+		"attr", "root", "root", 4, expected_index_range, expected_index_oids_range);
+}
+
+void test_diff_iterator__index_range_empty_0(void)
+{
+	index_iterator_test(
+		"attr", "empty", "empty", 0, NULL, NULL);
+}
+
+void test_diff_iterator__index_range_empty_1(void)
+{
+	index_iterator_test(
+		"attr", "z_empty_after", NULL, 0, NULL, NULL);
+}
+
+void test_diff_iterator__index_range_empty_2(void)
+{
+	index_iterator_test(
+		"attr", NULL, ".aaa_empty_before", 0, NULL, NULL);
 }
 
 static const char *expected_index_1[] = {
@@ -300,7 +404,8 @@ static const char* expected_index_oids_1[] = {
 
 void test_diff_iterator__index_1(void)
 {
-	index_iterator_test("status", 13, expected_index_1, expected_index_oids_1);
+	index_iterator_test(
+		"status", NULL, NULL, 13, expected_index_1, expected_index_oids_1);
 }
 
 
@@ -308,6 +413,8 @@ void test_diff_iterator__index_1(void)
 
 static void workdir_iterator_test(
 	const char *sandbox,
+	const char *start,
+	const char *end,
 	int expected_count,
 	int expected_ignores,
 	const char **expected_names,
@@ -318,7 +425,7 @@ static void workdir_iterator_test(
 	int count = 0, count_all = 0;
 	git_repository *repo = cl_git_sandbox_init(sandbox);
 
-	cl_git_pass(git_iterator_for_workdir(repo, &i));
+	cl_git_pass(git_iterator_for_workdir_range(&i, repo, start, end));
 	cl_git_pass(git_iterator_current(i, &entry));
 
 	while (entry != NULL) {
@@ -350,7 +457,7 @@ static void workdir_iterator_test(
 
 void test_diff_iterator__workdir_0(void)
 {
-	workdir_iterator_test("attr", 25, 2, NULL, "ign");
+	workdir_iterator_test("attr", NULL, NULL, 25, 2, NULL, "ign");
 }
 
 static const char *status_paths[] = {
@@ -372,5 +479,92 @@ static const char *status_paths[] = {
 
 void test_diff_iterator__workdir_1(void)
 {
-	workdir_iterator_test("status", 12, 1, status_paths, "ignored_file");
+	workdir_iterator_test(
+		"status", NULL, NULL, 12, 1, status_paths, "ignored_file");
+}
+
+static const char *status_paths_range_0[] = {
+	"staged_changes",
+	"staged_changes_modified_file",
+	"staged_delete_modified_file",
+	"staged_new_file",
+	"staged_new_file_modified_file",
+	NULL
+};
+
+void test_diff_iterator__workdir_1_ranged_0(void)
+{
+	workdir_iterator_test(
+		"status", "staged", "staged", 5, 0, status_paths_range_0, NULL);
+}
+
+static const char *status_paths_range_1[] = {
+	"modified_file", NULL
+};
+
+void test_diff_iterator__workdir_1_ranged_1(void)
+{
+	workdir_iterator_test(
+		"status", "modified_file", "modified_file",
+		1, 0, status_paths_range_1, NULL);
+}
+
+static const char *status_paths_range_3[] = {
+	"subdir.txt",
+	"subdir/current_file",
+	"subdir/modified_file",
+	NULL
+};
+
+void test_diff_iterator__workdir_1_ranged_3(void)
+{
+	workdir_iterator_test(
+		"status", "subdir", "subdir/modified_file",
+		3, 0, status_paths_range_3, NULL);
+}
+
+static const char *status_paths_range_4[] = {
+	"subdir/current_file",
+	"subdir/modified_file",
+	"subdir/new_file",
+	NULL
+};
+
+void test_diff_iterator__workdir_1_ranged_4(void)
+{
+	workdir_iterator_test(
+		"status", "subdir/", NULL, 3, 0, status_paths_range_4, NULL);
+}
+
+static const char *status_paths_range_5[] = {
+	"subdir/modified_file",
+	NULL
+};
+
+void test_diff_iterator__workdir_1_ranged_5(void)
+{
+	workdir_iterator_test(
+		"status", "subdir/modified_file", "subdir/modified_file",
+		1, 0, status_paths_range_5, NULL);
+}
+
+void test_diff_iterator__workdir_1_ranged_empty_0(void)
+{
+	workdir_iterator_test(
+		"status", "z_does_not_exist", NULL,
+		0, 0, NULL, NULL);
+}
+
+void test_diff_iterator__workdir_1_ranged_empty_1(void)
+{
+	workdir_iterator_test(
+		"status", "empty", "empty",
+		0, 0, NULL, NULL);
+}
+
+void test_diff_iterator__workdir_1_ranged_empty_2(void)
+{
+	workdir_iterator_test(
+		"status", NULL, "aaaa_empty_before",
+		0, 0, NULL, NULL);
 }
diff --git a/tests-clar/status/submodules.c b/tests-clar/status/submodules.c
index de971be..9423e84 100644
--- a/tests-clar/status/submodules.c
+++ b/tests-clar/status/submodules.c
@@ -103,3 +103,10 @@ void test_status_submodules__1(void)
 
 	cl_assert(index == 6);
 }
+
+void test_status_submodules__single_file(void)
+{
+	unsigned int status;
+	cl_git_pass( git_status_file(&status, g_repo, "testrepo") );
+	cl_assert(status == 0);
+}