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-rw-r--r--src/zix/btree.c61
1 files changed, 31 insertions, 30 deletions
diff --git a/src/zix/btree.c b/src/zix/btree.c
index 26885e2..b03a6c5 100644
--- a/src/zix/btree.c
+++ b/src/zix/btree.c
@@ -25,8 +25,8 @@
// #define ZIX_BTREE_DEBUG 1
#define ZIX_BTREE_PAGE_SIZE 4096
-#define ZIX_BTREE_NODE_SPACE (ZIX_BTREE_PAGE_SIZE - 2 * sizeof(uint32_t))
-#define ZIX_BTREE_LEAF_VALS (ZIX_BTREE_NODE_SPACE / sizeof(void*))
+#define ZIX_BTREE_NODE_SPACE (ZIX_BTREE_PAGE_SIZE - 2 * sizeof(uint16_t))
+#define ZIX_BTREE_LEAF_VALS ((ZIX_BTREE_NODE_SPACE / sizeof(void*)) - 1)
#define ZIX_BTREE_INODE_VALS (ZIX_BTREE_LEAF_VALS / 2)
struct ZixBTreeImpl {
@@ -39,8 +39,9 @@ struct ZixBTreeImpl {
};
struct ZixBTreeNodeImpl {
- uint32_t is_leaf;
- uint32_t n_vals;
+ uint16_t is_leaf;
+ uint16_t n_vals;
+ // On 64-bit we rely on some padding here to get page-sized nodes
void* vals[ZIX_BTREE_INODE_VALS]; // ZIX_BTREE_LEAF_VALS for leaves
ZixBTreeNode* children[ZIX_BTREE_INODE_VALS + 1]; // Nonexistent for leaves
};
@@ -51,7 +52,7 @@ typedef struct {
} ZixBTreeIterFrame;
struct ZixBTreeIterImpl {
- unsigned level; ///< Current level in pos
+ unsigned level; ///< Current level in stack
ZixBTreeIterFrame stack[]; ///< Position stack
};
@@ -61,7 +62,7 @@ ZIX_PRIVATE void
print_node(const ZixBTreeNode* n, const char* prefix)
{
printf("%s[", prefix);
- for (unsigned v = 0; v < n->n_vals; ++v) {
+ for (uint16_t v = 0; v < n->n_vals; ++v) {
printf(" %lu", (uintptr_t)n->vals[v]);
}
printf(" ]\n");
@@ -79,7 +80,7 @@ print_tree(const ZixBTreeNode* parent, const ZixBTreeNode* node, int level)
}
print_node(node, "");
if (!node->is_leaf) {
- for (unsigned i = 0; i < node->n_vals + 1; ++i) {
+ for (uint16_t i = 0; i < node->n_vals + 1; ++i) {
print_tree(node, node->children[i], level + 1);
}
}
@@ -129,12 +130,12 @@ zix_btree_free_rec(ZixBTree* const t, ZixBTreeNode* const n)
{
if (n) {
if (t->destroy) {
- for (unsigned i = 0; i < n->n_vals; ++i) {
+ for (uint16_t i = 0; i < n->n_vals; ++i) {
t->destroy(n->vals[i]);
}
}
if (!n->is_leaf) {
- for (unsigned i = 0; i < n->n_vals + 1; ++i) {
+ for (uint16_t i = 0; i < n->n_vals + 1; ++i) {
zix_btree_free_rec(t, n->children[i]);
}
}
@@ -157,13 +158,13 @@ zix_btree_size(const ZixBTree* const t)
return t->size;
}
-ZIX_PRIVATE unsigned
+ZIX_PRIVATE uint16_t
zix_btree_max_vals(const ZixBTreeNode* const node)
{
return node->is_leaf ? ZIX_BTREE_LEAF_VALS : ZIX_BTREE_INODE_VALS;
}
-ZIX_PRIVATE unsigned
+ZIX_PRIVATE uint16_t
zix_btree_min_vals(const ZixBTreeNode* const node)
{
return ((zix_btree_max_vals(node) + 1) / 2) - 1;
@@ -172,8 +173,8 @@ zix_btree_min_vals(const ZixBTreeNode* const node)
/** Shift pointers in `array` of length `n` right starting at `i`. */
ZIX_PRIVATE void
zix_btree_ainsert(void** const array,
- const unsigned n,
- const unsigned i,
+ const uint16_t n,
+ const uint16_t i,
void* const e)
{
memmove(array + i + 1, array + i, (n - i) * sizeof(e));
@@ -182,7 +183,7 @@ zix_btree_ainsert(void** const array,
/** Erase element `i` in `array` of length `n` and return erased element. */
ZIX_PRIVATE void*
-zix_btree_aerase(void** const array, const unsigned n, const unsigned i)
+zix_btree_aerase(void** const array, const uint16_t n, const uint16_t i)
{
void* const ret = array[i];
memmove(array + i, array + i + 1, (n - i) * sizeof(ret));
@@ -192,7 +193,7 @@ zix_btree_aerase(void** const array, const unsigned n, const unsigned i)
/** Split lhs, the i'th child of `n`, into two nodes. */
ZIX_PRIVATE ZixBTreeNode*
zix_btree_split_child(ZixBTreeNode* const n,
- const uint32_t i,
+ const uint16_t i,
ZixBTreeNode* const lhs)
{
assert(lhs->n_vals == zix_btree_max_vals(lhs));
@@ -200,7 +201,7 @@ zix_btree_split_child(ZixBTreeNode* const n,
assert(i < n->n_vals + 1);
assert(n->children[i] == lhs);
- const unsigned max_n_vals = zix_btree_max_vals(lhs);
+ const uint16_t max_n_vals = zix_btree_max_vals(lhs);
ZixBTreeNode* rhs = zix_btree_node_new(lhs->is_leaf);
if (!rhs) {
return NULL;
@@ -232,23 +233,23 @@ zix_btree_split_child(ZixBTreeNode* const n,
}
/** Find the first value in `n` that is not less than `e` (lower bound). */
-ZIX_PRIVATE unsigned
+ZIX_PRIVATE uint16_t
zix_btree_node_find(const ZixBTree* const t,
const ZixBTreeNode* const n,
const void* const e,
bool* const equal)
{
- unsigned first = 0;
- unsigned len = n->n_vals;
+ uint16_t first = 0;
+ uint16_t len = n->n_vals;
while (len > 0) {
- const unsigned half = len >> 1;
- const unsigned i = first + half;
+ const uint16_t half = len >> 1;
+ const uint16_t i = first + half;
const int cmp = t->cmp(n->vals[i], e, t->cmp_data);
if (cmp == 0) {
*equal = true;
len = half; // Keep searching for wildcard matches
} else if (cmp < 0) {
- const unsigned chop = half + 1;
+ const uint16_t chop = half + 1;
first += chop;
len -= chop;
} else {
@@ -264,7 +265,7 @@ zix_btree_insert(ZixBTree* const t, void* const e)
{
ZixBTreeNode* parent = NULL; // Parent of n
ZixBTreeNode* n = t->root; // Current node
- unsigned i = 0; // Index of n in parent
+ uint16_t i = 0; // Index of n in parent
while (n) {
if (n->n_vals == zix_btree_max_vals(n)) {
// Node is full, split to ensure there is space for a leaf split
@@ -325,7 +326,7 @@ zix_btree_node_is_minimal(ZixBTreeNode* const n)
/** Enlarge left child by stealing a value from its right sibling. */
ZIX_PRIVATE ZixBTreeNode*
-zix_btree_rotate_left(ZixBTreeNode* const parent, const unsigned i)
+zix_btree_rotate_left(ZixBTreeNode* const parent, const uint16_t i)
{
ZixBTreeNode* const lhs = parent->children[i];
ZixBTreeNode* const rhs = parent->children[i + 1];
@@ -347,7 +348,7 @@ zix_btree_rotate_left(ZixBTreeNode* const parent, const unsigned i)
/** Enlarge right child by stealing a value from its left sibling. */
ZIX_PRIVATE ZixBTreeNode*
-zix_btree_rotate_right(ZixBTreeNode* const parent, const unsigned i)
+zix_btree_rotate_right(ZixBTreeNode* const parent, const uint16_t i)
{
ZixBTreeNode* const lhs = parent->children[i - 1];
ZixBTreeNode* const rhs = parent->children[i];
@@ -371,7 +372,7 @@ zix_btree_rotate_right(ZixBTreeNode* const parent, const unsigned i)
/** Move n[i] down, merge the left and right child, return the merged node. */
ZIX_PRIVATE ZixBTreeNode*
-zix_btree_merge(ZixBTree* const t, ZixBTreeNode* const n, const unsigned i)
+zix_btree_merge(ZixBTree* const t, ZixBTreeNode* const n, const uint16_t i)
{
ZixBTreeNode* const lhs = n->children[i];
ZixBTreeNode* const rhs = n->children[i + 1];
@@ -462,7 +463,7 @@ zix_btree_remove_rec(ZixBTree* const t,
assert(n == t->root || !zix_btree_node_is_minimal(n));
bool equal = false;
- const unsigned i = zix_btree_node_find(t, n, e, &equal);
+ const uint16_t i = zix_btree_node_find(t, n, e, &equal);
if (n->is_leaf) {
if (equal) {
@@ -504,7 +505,7 @@ zix_btree_remove_rec(ZixBTree* const t,
return zix_btree_remove_rec(t, lhs, e, removed);
} else {
// Both child's siblings are minimal, merge them
- const unsigned m = (i < n->n_vals) ? i : i - 1;
+ const uint16_t m = (i < n->n_vals) ? i : i - 1;
ZixBTreeNode* const merged = zix_btree_merge(t, n, m);
return zix_btree_remove_rec(t, merged, e, removed);
}
@@ -550,7 +551,7 @@ zix_btree_find(const ZixBTree* const t,
while (n) {
bool equal = false;
- const unsigned i = zix_btree_node_find(t, n, e, &equal);
+ const uint16_t i = zix_btree_node_find(t, n, e, &equal);
// Update iterator stack
(*ti)->stack[(*ti)->level].node = n;
@@ -585,7 +586,7 @@ zix_btree_lower_bound(const ZixBTree* const t,
while (n) {
bool equal = false;
- const unsigned i = zix_btree_node_find(t, n, e, &equal);
+ const uint16_t i = zix_btree_node_find(t, n, e, &equal);
// Update iterator stack
(*ti)->stack[(*ti)->level].node = n;
generated by cgit v1.2.1 (git 2.18.0) at 2024-12-30 23:04:47 +0000