From 0135d1a112a4e7abe1ea640ad17714eb0d713634 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bj=C3=B6rn=20Linse?= <bjorn.linse@gmail.com>
Date: Sun, 7 Aug 2016 14:10:07 +0200
Subject: [PATCH] kbtree: add kb_itr_prev and more precise kb_itr_getp

---
 kbtree.h | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/kbtree.h b/kbtree.h
index 8b4f9176..865d5316 100644
--- a/kbtree.h
+++ b/kbtree.h
@@ -359,7 +359,37 @@ typedef struct {
 			if (itr->p < itr->stack) return 0; \
 			if (itr->p->x && itr->p->i < itr->p->x->n) return 1; \
 		} \
-	}
+	} \
+	static inline int kb_itr_prev_##name(kbtree_##name##_t *b, kbitr_t *itr) \
+	{ \
+		if (itr->p < itr->stack) return 0; \
+		for (;;) { \
+			while (itr->p->x && itr->p->i >= 0) { \
+				itr->p[1].x = itr->p->x->is_internal? __KB_PTR(b, itr->p->x)[itr->p->i] : 0; \
+				itr->p[1].i = itr->p[1].x ? itr->p[1].x->n : -1; \
+				++itr->p; \
+			} \
+			--itr->p; \
+			if (itr->p < itr->stack) return 0; \
+			--itr->p->i; \
+			if (itr->p->x && itr->p->i >= 0) return 1; \
+		} \
+	} \
+	static int kb_itr_getp_##name(kbtree_##name##_t *b, const key_t * __restrict k, kbitr_t *itr) \
+	{ \
+		int i, r = 0; \
+		itr->p = itr->stack; \
+		itr->p->x = b->root; \
+		while (itr->p->x) { \
+			i = __kb_getp_aux_##name(itr->p->x, k, &r); \
+			itr->p->i = i; \
+			if (i >= 0 && r == 0) return 1; \
+			++itr->p->i; \
+			itr->p[1].x = itr->p->x->is_internal? __KB_PTR(b, itr->p->x)[i + 1] : 0; \
+			++itr->p; \
+		} \
+		return 0; \
+	} \
 
 #define KBTREE_INIT(name, key_t, __cmp)			\
 	__KB_TREE_T(name)							\
@@ -387,7 +417,9 @@ typedef struct {
 
 #define kb_itr_first(name, b, i) kb_itr_first_##name(b, i)
 #define kb_itr_get(name, b, k, i) kb_itr_get_##name(b, k, i)
+#define kb_itr_getp(name, b, k, i) kb_itr_getp_##name(b, k, i)
 #define kb_itr_next(name, b, i) kb_itr_next_##name(b, i)
+#define kb_itr_prev(name, b, i) kb_itr_prev_##name(b, i)
 #define kb_itr_key(type, itr) __KB_KEY(type, (itr)->p->x)[(itr)->p->i]
 #define kb_itr_valid(itr) ((itr)->p >= (itr)->stack)