From a463773c12aacb11bc370cddd053f6cc7d08e68a Mon Sep 17 00:00:00 2001
From: Werner Almesberger <werner@openmoko.org>
Date: Fri, 19 Nov 2010 20:30:24 -0300
Subject: [PATCH] qpkg: simplify jrb_delete_node and more whitespace cleanup

- jrb.c (recolor, jrb_delete_node, jrb_nblack, jrb_free_tree): add space
  to while(...
- jrb.c (jrb_delete_node): flatten deletion of internal node
- rbtest.c (main): add test of jrb_delete_node
---
 qpkg/jrb.c    | 87 +++++++++++++++++++++++++--------------------------
 qpkg/rbtest.c |  4 +++
 2 files changed, 46 insertions(+), 45 deletions(-)

diff --git a/qpkg/jrb.c b/qpkg/jrb.c
index 71e84ae..2046cef 100644
--- a/qpkg/jrb.c
+++ b/qpkg/jrb.c
@@ -272,7 +272,7 @@ static void recolor(JRB n)
 	JRB p, gp, s;
 	int done = 0;
  
-	while(!done) {
+	while (!done) {
 		if (isroot(n)) {
 			setblack(n);
 			return;
@@ -360,8 +360,8 @@ static void single_rotate(JRB y, int l)
 
 void jrb_delete_node(JRB n)
 {
-	JRB s, p, gp;
-	char ir;
+	JRB s, p, gp, x, z;
+	char ir, il;
  
 	if (isint(n)) {
 		fprintf(stderr, "Cannot delete an internal node: %p\n", n);
@@ -430,7 +430,7 @@ void jrb_delete_node(JRB n)
 	n = s;
 	p = n->parent;
 	s = sibling(n);
-	while(isblack(p) && isblack(s) && isint(s) && 
+	while (isblack(p) && isblack(s) && isint(s) && 
 	    isblack(s->flink) && isblack(s->blink)) {
 		setred(s);
 		n = p;
@@ -447,49 +447,46 @@ void jrb_delete_node(JRB n)
 		s = sibling(n);
 	}
     
-	{
-		JRB x, z; char il;
-    
-		if (isext(s)) {
+	if (isext(s)) {
+		fprintf(stderr, "DELETION ERROR: sibling not internal\n");
+		exit(1);
+	}
+ 
+	il = isleft(n);
+	x = il ? s->flink : s->blink;
+	z = sibling(x);
+ 
+	if (isred(z)) {  /* Rotation 2.3f */
+		single_rotate(p, !il);
+		setblack(z);
+		if (isred(p))
+			setred(s);
+		else
+			setblack(s);
+		setblack(p);
+		return;
+	}
+	if (isblack(x)) {   /* Recoloring only (2.3c) */
+		if (isred(s) || isblack(p)) {
 			fprintf(stderr,
-			    "DELETION ERROR: sibling not internal\n");
+			    "DELETION ERROR: 2.3c not quite right\n");
 			exit(1);
 		}
- 
-		il = isleft(n);
-		x = il ? s->flink : s->blink;
-		z = sibling(x);
- 
-		if (isred(z)) {  /* Rotation 2.3f */
-			single_rotate(p, !il);
-			setblack(z);
-			if (isred(p))
-				setred(s);
-			else
-				setblack(s);
-			setblack(p);
-		} else if (isblack(x)) {   /* Recoloring only (2.3c) */
-			if (isred(s) || isblack(p)) {
-				fprintf(stderr,
-				    "DELETION ERROR: 2.3c not quite right\n");
-				exit(1);
-			}
-			setblack(p);
-			setred(s);
-			return;
-		} else if (isred(p)) { /* 2.3d */
-			single_rotate(s, il);
-			single_rotate(p, !il);
-			setblack(x);
-			setred(s);
-			return;
-		} else {  /* 2.3e */
-			single_rotate(s, il);
-			single_rotate(p, !il);
-			setblack(x);
-			return;
-		}
+		setblack(p);
+		setred(s);
+		return;
 	}
+	if (isred(p)) { /* 2.3d */
+		single_rotate(s, il);
+		single_rotate(p, !il);
+		setblack(x);
+		setred(s);
+	return;
+	}
+	/* 2.3e */
+	single_rotate(s, il);
+	single_rotate(p, !il);
+	setblack(x);
 }
 
  
@@ -503,7 +500,7 @@ int jrb_nblack(JRB n)
 		exit(1);
 	}
 	nb = 0;
-	while(!ishead(n)) {
+	while (!ishead(n)) {
 		if (isblack(n)) nb++;
 		n = n->parent;
 	}
@@ -537,7 +534,7 @@ void jrb_free_tree(JRB n)
 		exit(1);
 	}
  
-	while(jrb_first(n) != jrb_nil(n))
+	while (jrb_first(n) != jrb_nil(n))
 		jrb_delete_node(jrb_first(n));
 
 	free(n);
diff --git a/qpkg/rbtest.c b/qpkg/rbtest.c
index c7e62af..e0bed09 100644
--- a/qpkg/rbtest.c
+++ b/qpkg/rbtest.c
@@ -21,6 +21,7 @@ int main(void)
 	JRB p;
 
 	INSERT("ab", "have");
+	INSERT("ac", "NOT");
 	INSERT("d", "little");
 	INSERT("c", "this");
 	INSERT("b", "passed");
@@ -29,6 +30,9 @@ int main(void)
 	INSERT("aa", "We");
 	INSERT("ff", "!");
 
+	p = jrb_find(tree, "ac", cmp);
+	jrb_delete_node(p);
+
 	jrb_traverse(p, tree)
 		printf("%s ", (char *) jrb_val(p));
 	printf("\n");