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remove macro A_RBT_(R|B)
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@tqfx
tqfx committed Jun 22, 2024
1 parent accbbaf commit 89ec533
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Showing 2 changed files with 61 additions and 58 deletions.
5 changes: 1 addition & 4 deletions include/a/rbt.h
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Original file line number Diff line number Diff line change
Expand Up @@ -18,9 +18,6 @@
#define A_RBT_ROOT {A_NULL}
// clang-format on

#define A_RBT_R 0 //!< red
#define A_RBT_B 1 //!< black

/*!
@brief instance structure for red–black binary search tree node
*/
Expand Down Expand Up @@ -67,7 +64,7 @@ A_INTERN a_rbt_node *a_rbt_init(a_rbt_node *node, a_rbt_node *parent)
node->parent_ = a_cast_r(a_uptr, parent);
#else /* !A_SIZE_POINTER */
node->parent = parent;
node->color = A_RBT_R;
node->color = 0;
#endif /* A_SIZE_POINTER */
node->right = A_NULL;
node->left = A_NULL;
Expand Down
114 changes: 60 additions & 54 deletions src/rbt.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -43,7 +43,7 @@ static A_INLINE void a_rbt_new_child(a_rbt *root, a_rbt_node *parent, a_rbt_node
static A_INLINE void a_rbt_set_parent_color(a_rbt_node *node, a_rbt_node *parent, unsigned int color)
{
#if defined(A_SIZE_POINTER) && (A_SIZE_POINTER + 0 > 1)
node->parent_ = (a_uptr)parent | color;
node->parent_ = (a_uptr)parent + color;
#else /* !A_SIZE_POINTER */
node->parent = parent;
node->color = color;
Expand All @@ -54,7 +54,7 @@ static A_INLINE void a_rbt_set_parent_color(a_rbt_node *node, a_rbt_node *parent
static A_INLINE void a_rbt_set_parent(a_rbt_node *node, a_rbt_node *parent)
{
#if defined(A_SIZE_POINTER) && (A_SIZE_POINTER + 0 > 1)
node->parent_ = (a_uptr)parent | (node->parent_ & 1);
node->parent_ = (a_uptr)parent + (node->parent_ & 1);
#else /* !A_SIZE_POINTER */
node->parent = parent;
#endif /* A_SIZE_POINTER */
Expand All @@ -74,9 +74,9 @@ static A_INLINE unsigned int a_rbt_color(a_rbt_node const *node)
static A_INLINE void a_rbt_set_black(a_rbt_node *node)
{
#if defined(A_SIZE_POINTER) && (A_SIZE_POINTER + 0 > 1)
node->parent_ |= A_RBT_B;
node->parent_ |= 1;
#else /* !A_SIZE_POINTER */
node->color = A_RBT_B;
node->color = 1;
#endif /* A_SIZE_POINTER */
}

Expand All @@ -98,9 +98,15 @@ static A_INLINE void a_rbt_set_parents(a_rbt *root, a_rbt_node *node, a_rbt_node
a_rbt_new_child(root, parent, node, newnode);
}

#if defined(A_SIZE_POINTER) && (A_SIZE_POINTER + 0 > 1)
#define A_RBT_PARENT(node) a_cast_r(a_rbt_node *, (node)->parent_)
#else /* !A_SIZE_POINTER */
#define A_RBT_PARENT(node) (node)->parent
#endif /* A_SIZE_POINTER */

void a_rbt_insert_adjust(a_rbt *root, a_rbt_node *node)
{
for (a_rbt_node *parent = a_rbt_parent(node), *gparent, *tmp;;)
for (a_rbt_node *parent = A_RBT_PARENT(node), *gparent, *tmp;;)
{
/* Loop invariant: node is red. */
if (A_UNLIKELY(!parent))
Expand All @@ -109,19 +115,19 @@ void a_rbt_insert_adjust(a_rbt *root, a_rbt_node *node)
The inserted node is root. Either this is the first node,
or we recursed at Case 1 below and are no longer violating 4).
*/
a_rbt_set_parent_color(node, A_NULL, A_RBT_B);
a_rbt_set_parent_color(node, A_NULL, 1);
break;
}
/*
If there is a black parent, we are done. Otherwise, take some corrective action as, per 4),
we don't want a red root or two consecutive red nodes.
*/
if (a_rbt_color(parent) == A_RBT_B) { break; }
gparent = a_rbt_parent(parent);
if (a_rbt_color(parent)) { break; }
gparent = A_RBT_PARENT(parent);
tmp = gparent->right;
if (parent != tmp) /* parent == gparent->left */
{
if (tmp && a_rbt_color(tmp) == A_RBT_R)
if (tmp && a_rbt_color(tmp) == 0)
{
/*
Case 1 - node's uncle is red (color flips).
Expand All @@ -134,11 +140,11 @@ void a_rbt_insert_adjust(a_rbt *root, a_rbt_node *node)
However, since g's parent might be red, and 4) does not allow this, we need to recurse at g.
*/
a_rbt_set_parent_color(tmp, gparent, A_RBT_B);
a_rbt_set_parent_color(parent, gparent, A_RBT_B);
a_rbt_set_parent_color(tmp, gparent, 1);
a_rbt_set_parent_color(parent, gparent, 1);
node = gparent;
parent = a_rbt_parent(node);
a_rbt_set_parent_color(node, parent, A_RBT_R);
a_rbt_set_parent_color(node, parent, 0);
continue;
}
tmp = parent->right;
Expand All @@ -158,8 +164,8 @@ void a_rbt_insert_adjust(a_rbt *root, a_rbt_node *node)
tmp = node->left;
parent->right = tmp;
node->left = parent;
if (tmp) { a_rbt_set_parent_color(tmp, parent, A_RBT_B); }
a_rbt_set_parent_color(parent, node, A_RBT_R);
if (tmp) { a_rbt_set_parent_color(tmp, parent, 1); }
a_rbt_set_parent_color(parent, node, 0);
parent = node;
tmp = node->right;
}
Expand All @@ -175,21 +181,21 @@ void a_rbt_insert_adjust(a_rbt *root, a_rbt_node *node)
*/
gparent->left = tmp; /* == parent->right */
parent->right = gparent;
if (tmp) { a_rbt_set_parent_color(tmp, gparent, A_RBT_B); }
a_rbt_set_parents(root, gparent, parent, A_RBT_R);
if (tmp) { a_rbt_set_parent_color(tmp, gparent, 1); }
a_rbt_set_parents(root, gparent, parent, 0);
break;
}
else
{
tmp = gparent->left;
if (tmp && a_rbt_color(tmp) == A_RBT_R)
if (tmp && a_rbt_color(tmp) == 0)
{
/* Case 1 - color flips */
a_rbt_set_parent_color(tmp, gparent, A_RBT_B);
a_rbt_set_parent_color(parent, gparent, A_RBT_B);
a_rbt_set_parent_color(tmp, gparent, 1);
a_rbt_set_parent_color(parent, gparent, 1);
node = gparent;
parent = a_rbt_parent(node);
a_rbt_set_parent_color(node, parent, A_RBT_R);
a_rbt_set_parent_color(node, parent, 0);
continue;
}
tmp = parent->left;
Expand All @@ -199,16 +205,16 @@ void a_rbt_insert_adjust(a_rbt *root, a_rbt_node *node)
tmp = node->right;
parent->left = tmp;
node->right = parent;
if (tmp) { a_rbt_set_parent_color(tmp, parent, A_RBT_B); }
a_rbt_set_parent_color(parent, node, A_RBT_R);
if (tmp) { a_rbt_set_parent_color(tmp, parent, 1); }
a_rbt_set_parent_color(parent, node, 0);
parent = node;
tmp = node->left;
}
/* Case 3 - left rotate at gparent */
gparent->right = tmp; /* == parent->left */
parent->left = gparent;
if (tmp) { a_rbt_set_parent_color(tmp, gparent, A_RBT_B); }
a_rbt_set_parents(root, gparent, parent, A_RBT_R);
if (tmp) { a_rbt_set_parent_color(tmp, gparent, 1); }
a_rbt_set_parents(root, gparent, parent, 0);
break;
}
}
Expand All @@ -228,7 +234,7 @@ static A_INLINE void a_rbt_remove_adjust(a_rbt *root, a_rbt_node *parent)
if (node != parent->right) /* node == parent->left */
{
sibling = parent->right;
if (a_rbt_color(sibling) == A_RBT_R)
if (a_rbt_color(sibling) == 0)
{
/*
Case 1 - left rotate at parent
Expand All @@ -242,16 +248,16 @@ static A_INLINE void a_rbt_remove_adjust(a_rbt *root, a_rbt_node *parent)
tmp1 = sibling->left;
parent->right = tmp1;
sibling->left = parent;
a_rbt_set_parent_color(tmp1, parent, A_RBT_B);
a_rbt_set_parents(root, parent, sibling, A_RBT_R);
a_rbt_set_parent_color(tmp1, parent, 1);
a_rbt_set_parents(root, parent, sibling, 0);
sibling = tmp1;
A_ASSUME(tmp1);
}
tmp1 = sibling->right;
if (!tmp1 || a_rbt_color(tmp1) == A_RBT_B)
if (!tmp1 || a_rbt_color(tmp1))
{
tmp2 = sibling->left;
if (!tmp2 || a_rbt_color(tmp2) == A_RBT_B)
if (!tmp2 || a_rbt_color(tmp2))
{
/*
Case 2 - sibling color flip (p could be either color here)
Expand All @@ -265,8 +271,8 @@ static A_INLINE void a_rbt_remove_adjust(a_rbt *root, a_rbt_node *parent)
This leaves us violating 5) which can be fixed by flipping p to black if it was red,
or by recursing at p. p is red when coming from Case 1.
*/
a_rbt_set_parent_color(sibling, parent, A_RBT_R);
if (a_rbt_color(parent) == A_RBT_R)
a_rbt_set_parent_color(sibling, parent, 0);
if (a_rbt_color(parent) == 0)
{
a_rbt_set_black(parent);
}
Expand All @@ -290,7 +296,7 @@ static A_INLINE void a_rbt_remove_adjust(a_rbt *root, a_rbt_node *parent)
Sr
Note: p might be red, and then both p and sl are red after rotation(which breaks property 4).
This is fixed in Case 4 (in a_rbt_set_parents() which set sl the color of p and set A_RBT_B)
This is fixed in Case 4 (in a_rbt_set_parents() which set sl the color of p and set black)
(p) (sl)
/ \ / \
Expand All @@ -304,7 +310,7 @@ static A_INLINE void a_rbt_remove_adjust(a_rbt *root, a_rbt_node *parent)
sibling->left = tmp1;
tmp2->right = sibling;
parent->right = tmp2;
if (tmp1) { a_rbt_set_parent_color(tmp1, sibling, A_RBT_B); }
if (tmp1) { a_rbt_set_parent_color(tmp1, sibling, 1); }
tmp1 = sibling;
sibling = tmp2;
}
Expand All @@ -321,35 +327,35 @@ static A_INLINE void a_rbt_remove_adjust(a_rbt *root, a_rbt_node *parent)
tmp2 = sibling->left;
parent->right = tmp2;
sibling->left = parent;
a_rbt_set_parent_color(tmp1, sibling, A_RBT_B);
a_rbt_set_parent_color(tmp1, sibling, 1);
if (tmp2) { a_rbt_set_parent(tmp2, parent); }
a_rbt_set_parents(root, parent, sibling, A_RBT_B);
a_rbt_set_parents(root, parent, sibling, 1);
break;
}
else
{
A_ASSUME(parent->left);
sibling = parent->left;
if (a_rbt_color(sibling) == A_RBT_R)
if (a_rbt_color(sibling) == 0)
{
/* Case 1 - right rotate at parent */
tmp1 = sibling->right;
parent->left = tmp1;
sibling->right = parent;
a_rbt_set_parent_color(tmp1, parent, A_RBT_B);
a_rbt_set_parents(root, parent, sibling, A_RBT_R);
a_rbt_set_parent_color(tmp1, parent, 1);
a_rbt_set_parents(root, parent, sibling, 0);
sibling = tmp1;
A_ASSUME(tmp1);
}
tmp1 = sibling->left;
if (!tmp1 || a_rbt_color(tmp1) == A_RBT_B)
if (!tmp1 || a_rbt_color(tmp1))
{
tmp2 = sibling->right;
if (!tmp2 || a_rbt_color(tmp2) == A_RBT_B)
if (!tmp2 || a_rbt_color(tmp2))
{
/* Case 2 - sibling color flip */
a_rbt_set_parent_color(sibling, parent, A_RBT_R);
if (a_rbt_color(parent) == A_RBT_R)
a_rbt_set_parent_color(sibling, parent, 0);
if (a_rbt_color(parent) == 0)
{
a_rbt_set_black(parent);
}
Expand All @@ -366,17 +372,17 @@ static A_INLINE void a_rbt_remove_adjust(a_rbt *root, a_rbt_node *parent)
sibling->right = tmp1;
tmp2->left = sibling;
parent->left = tmp2;
if (tmp1) { a_rbt_set_parent_color(tmp1, sibling, A_RBT_B); }
if (tmp1) { a_rbt_set_parent_color(tmp1, sibling, 1); }
tmp1 = sibling;
sibling = tmp2;
}
/* Case 4 - right rotate at parent + color flips */
tmp2 = sibling->right;
parent->left = tmp2;
sibling->right = parent;
a_rbt_set_parent_color(tmp1, sibling, A_RBT_B);
a_rbt_set_parent_color(tmp1, sibling, 1);
if (tmp2) { a_rbt_set_parent(tmp2, parent); }
a_rbt_set_parents(root, parent, sibling, A_RBT_B);
a_rbt_set_parents(root, parent, sibling, 1);
break;
}
}
Expand All @@ -388,7 +394,7 @@ void a_rbt_remove(a_rbt *root, a_rbt_node *node)
a_rbt_node *tmp = node->left;
a_rbt_node *parent, *adjust;
#if defined(A_SIZE_POINTER) && (A_SIZE_POINTER + 0 > 1)
a_uptr pc;
a_uptr parent_;
#else /* !A_SIZE_POINTER */
unsigned int color;
#endif /* A_SIZE_POINTER */
Expand All @@ -401,7 +407,7 @@ void a_rbt_remove(a_rbt *root, a_rbt_node *node)
We adjust colors locally so as to bypass a_rbt_remove_adjust() later on.
*/
#if defined(A_SIZE_POINTER) && (A_SIZE_POINTER + 0 > 1)
pc = node->parent_;
parent_ = node->parent_;
#else /* !A_SIZE_POINTER */
color = node->color;
#endif /* A_SIZE_POINTER */
Expand All @@ -410,7 +416,7 @@ void a_rbt_remove(a_rbt *root, a_rbt_node *node)
if (child)
{
#if defined(A_SIZE_POINTER) && (A_SIZE_POINTER + 0 > 1)
child->parent_ = pc;
child->parent_ = parent_;
#else /* !A_SIZE_POINTER */
child->parent = parent;
child->color = color;
Expand All @@ -420,9 +426,9 @@ void a_rbt_remove(a_rbt *root, a_rbt_node *node)
else
{
#if defined(A_SIZE_POINTER) && (A_SIZE_POINTER + 0 > 1)
adjust = (pc & 1) == A_RBT_B ? parent : A_NULL;
adjust = (parent_ & 1) ? parent : A_NULL;
#else /* !A_SIZE_POINTER */
adjust = color == A_RBT_B ? parent : A_NULL;
adjust = color ? parent : A_NULL;
#endif /* A_SIZE_POINTER */
}
}
Expand Down Expand Up @@ -489,7 +495,7 @@ void a_rbt_remove(a_rbt *root, a_rbt_node *node)
a_rbt_set_parent(tmp, successor);

#if defined(A_SIZE_POINTER) && (A_SIZE_POINTER + 0 > 1)
pc = node->parent_;
parent_ = node->parent_;
#else /* !A_SIZE_POINTER */
color = node->color;
#endif /* A_SIZE_POINTER */
Expand All @@ -498,15 +504,15 @@ void a_rbt_remove(a_rbt *root, a_rbt_node *node)

if (child2)
{
a_rbt_set_parent_color(child2, parent, A_RBT_B);
a_rbt_set_parent_color(child2, parent, 1);
adjust = A_NULL;
}
else
{
adjust = a_rbt_color(successor) == A_RBT_B ? parent : A_NULL;
adjust = a_rbt_color(successor) ? parent : A_NULL;
}
#if defined(A_SIZE_POINTER) && (A_SIZE_POINTER + 0 > 1)
successor->parent_ = pc;
successor->parent_ = parent_;
#else /* !A_SIZE_POINTER */
successor->parent = tmp;
successor->color = color;
Expand Down

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