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Re-wrote broken codeblock_tree_delete() function.

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This commit is contained in:
SarahW 2016-05-12 21:21:49 +01:00
commit 2909742567
1 changed files with 92 additions and 62 deletions
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164
src/codegen.h
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@ -109,85 +109,115 @@ static inline void codeblock_tree_add(codeblock_t *new_block)
static inline void codeblock_tree_delete(codeblock_t *block) static inline void codeblock_tree_delete(codeblock_t *block)
{ {
while (1) codeblock_t *parent = block->parent;
{
codeblock_t *parent = block->parent;
if (!block->left && !block->right) if (!block->left && !block->right)
{
/*Easy case - remove from parent*/
if (!parent)
pages[block->phys >> 12].head = NULL;
else
{ {
/*Easy case - remove from parent*/ if (parent->left == block)
if (parent) parent->left = NULL;
{ if (parent->right == block)
if (parent->left == block) parent->right = NULL;
parent->left = NULL;
if (parent->right == block)
parent->right = NULL;
}
return;
} }
else if (!block->left) return;
}
else if (!block->left)
{
/*Only right node*/
if (!parent)
{ {
/*Only left node*/ pages[block->phys >> 12].head = block->right;
if (!parent) pages[block->phys >> 12].head->parent = NULL;
pages[block->phys >> 12].head = block->left;
else
{
if (parent->left == block)
parent->left = block->left;
if (parent->right == block)
parent->right = block->left;
}
return;
}
else if (!block->right)
{
/*Only right node*/
if (!parent)
pages[block->phys >> 12].head = block->right;
else
{
if (parent->left == block)
parent->left = block->right;
if (parent->right == block)
parent->right = block->right;
}
return;
} }
else else
{ {
/*Difficult case - node has two children. Walk right child to find lowest node*/ if (parent->left == block)
codeblock_t *lowest = block->right;
codeblock_t *old_parent;
while (lowest->left)
lowest = lowest->left;
old_parent = lowest->parent;
/*Replace deleted node with lowest node*/
if (!parent)
pages[block->phys >> 12].head = lowest;
else
{ {
if (parent->left == block) parent->left = block->right;
parent->left = lowest; parent->left->parent = parent;
if (parent->right == block)
parent->right = lowest;
} }
lowest->parent = parent; if (parent->right == block)
{
parent->right = block->right;
parent->right->parent = parent;
}
}
return;
}
else if (!block->right)
{
/*Only left node*/
if (!parent)
{
pages[block->phys >> 12].head = block->left;
pages[block->phys >> 12].head->parent = NULL;
}
else
{
if (parent->left == block)
{
parent->left = block->left;
parent->left->parent = parent;
}
if (parent->right == block)
{
parent->right = block->left;
parent->right->parent = parent;
}
}
return;
}
else
{
/*Difficult case - node has two children. Walk right child to find lowest node*/
codeblock_t *lowest = block->right, *highest;
codeblock_t *old_parent;
if (old_parent = block) while (lowest->left)
lowest = lowest->left;
old_parent = lowest->parent;
/*Replace deleted node with lowest node*/
if (!parent)
pages[block->phys >> 12].head = lowest;
else
{
if (parent->left == block)
parent->left = lowest;
if (parent->right == block)
parent->right = lowest;
}
lowest->parent = parent;
lowest->left = block->left;
if (lowest->left)
lowest->left->parent = lowest;
old_parent->left = NULL;
highest = lowest->right;
if (!highest)
{
if (lowest != block->right)
{ {
return; lowest->right = block->right;
} block->right->parent = lowest;
else
{
/*Replace old lowest node with deleted node, and loop*/
if (old_parent->left == lowest)
old_parent->left = block->left;
if (old_parent->right == lowest)
old_parent->right = block->right;
block->parent = old_parent;
} }
return;
}
while (highest->right)
highest = highest->right;
if (block->right && block->right != lowest)
{
highest->right = block->right;
block->right->parent = highest;
} }
} }
} }