diff options
Diffstat (limited to 'rdxtree.c')
| -rw-r--r-- | rdxtree.c | 96 |
1 files changed, 71 insertions, 25 deletions
@@ -52,6 +52,11 @@ #include "rdxtree.h" /* + * Mask applied on an entry to obtain its address. + */ +#define RDXTREE_ENTRY_ADDR_MASK (~0x3UL) + +/* * Global properties used to shape radix trees. */ #define RDXTREE_RADIX 6 @@ -107,6 +112,30 @@ struct rdxtree_node { void *entries[RDXTREE_RADIX_SIZE]; }; +static inline int +rdxtree_check_alignment(const void *ptr) +{ + return ((unsigned long)ptr & ~RDXTREE_ENTRY_ADDR_MASK) == 0; +} + +static inline void * +rdxtree_entry_addr(void *entry) +{ + return (void *)((unsigned long)entry & RDXTREE_ENTRY_ADDR_MASK); +} + +static inline int +rdxtree_entry_is_node(const void *entry) +{ + return ((unsigned long)entry & 1) != 0; +} + +static inline void * +rdxtree_node_to_entry(struct rdxtree_node *node) +{ + return (void *)((unsigned long)node | 1); +} + static int rdxtree_node_create(struct rdxtree_node **nodep, unsigned int height) { @@ -117,6 +146,7 @@ rdxtree_node_create(struct rdxtree_node **nodep, unsigned int height) if (node == NULL) return ERR_NOMEM; + assert(rdxtree_check_alignment(node)); node->parent = NULL; node->height = height; node->nr_entries = 0; @@ -160,13 +190,21 @@ rdxtree_node_empty(struct rdxtree_node *node) } static inline void -rdxtree_node_insert(struct rdxtree_node *node, unsigned int index, void *ptr) +rdxtree_node_insert(struct rdxtree_node *node, unsigned int index, + void *entry) { assert(index < ARRAY_SIZE(node->entries)); assert(node->entries[index] == NULL); node->nr_entries++; - node->entries[index] = ptr; + node->entries[index] = entry; +} + +static inline void +rdxtree_node_insert_node(struct rdxtree_node *node, unsigned int index, + struct rdxtree_node *child) +{ + rdxtree_node_insert(node, index, rdxtree_node_to_entry(child)); } static inline void @@ -185,7 +223,7 @@ rdxtree_node_find(struct rdxtree_node *node, unsigned int index, int get_slot) void *ptr; while (index < ARRAY_SIZE(node->entries)) { - ptr = node->entries[index]; + ptr = rdxtree_entry_addr(node->entries[index]); if (ptr != NULL) return get_slot ? (void *)&node->entries[index] : ptr; @@ -242,33 +280,34 @@ rdxtree_max_key(unsigned int height) static void rdxtree_shrink(struct rdxtree *tree) { - struct rdxtree_node *node, *child; + struct rdxtree_node *node; + void *entry; while (tree->height > 0) { - node = tree->root; + node = rdxtree_entry_addr(tree->root); if (node->nr_entries != 1) break; - child = node->entries[0]; + entry = node->entries[0]; - if (child == NULL) + if (entry == NULL) break; rdxtree_node_destroy(node); tree->height--; if (tree->height > 0) - rdxtree_node_unlink(child); + rdxtree_node_unlink(rdxtree_entry_addr(entry)); - tree->root = child; + tree->root = entry; } } static int rdxtree_grow(struct rdxtree *tree, unsigned long key) { - struct rdxtree_node *node; + struct rdxtree_node *root, *node; unsigned int new_height; int error; @@ -282,6 +321,8 @@ rdxtree_grow(struct rdxtree *tree, unsigned long key) return ERR_SUCCESS; } + root = rdxtree_entry_addr(tree->root); + do { error = rdxtree_node_create(&node, tree->height); @@ -295,14 +336,15 @@ rdxtree_grow(struct rdxtree *tree, unsigned long key) if (tree->height == 0) rdxtree_node_bm_clear(node, 0); else { - rdxtree_node_link(tree->root, node, 0); + rdxtree_node_link(root, node, 0); - if (rdxtree_node_bm_empty(tree->root)) + if (rdxtree_node_bm_empty(root)) rdxtree_node_bm_clear(node, 0); } - tree->root = node; tree->height++; + tree->root = rdxtree_node_to_entry(node); + root = node; } while (new_height > tree->height); return ERR_SUCCESS; @@ -358,6 +400,7 @@ rdxtree_insert_common(struct rdxtree *tree, unsigned long key, void *ptr, int error; assert(ptr != NULL); + assert(rdxtree_check_alignment(ptr)); if (key > rdxtree_max_key(tree->height)) { error = rdxtree_grow(tree, key); @@ -380,7 +423,7 @@ rdxtree_insert_common(struct rdxtree *tree, unsigned long key, void *ptr, return ERR_SUCCESS; } - node = tree->root; + node = rdxtree_entry_addr(tree->root); shift = (height - 1) * RDXTREE_RADIX; prev = NULL; @@ -398,16 +441,16 @@ rdxtree_insert_common(struct rdxtree *tree, unsigned long key, void *ptr, } if (prev == NULL) - tree->root = node; + tree->root = rdxtree_node_to_entry(node); else { - rdxtree_node_insert(prev, index, node); + rdxtree_node_insert_node(prev, index, node); rdxtree_node_link(node, prev, index); } } prev = node; index = (key >> shift) & RDXTREE_RADIX_MASK; - node = prev->entries[index]; + node = rdxtree_entry_addr(prev->entries[index]); shift -= RDXTREE_RADIX; height--; } while (height > 0); @@ -447,6 +490,7 @@ rdxtree_insert_alloc_common(struct rdxtree *tree, void *ptr, int error; assert(ptr != NULL); + assert(rdxtree_check_alignment(ptr)); height = tree->height; @@ -464,7 +508,7 @@ rdxtree_insert_alloc_common(struct rdxtree *tree, void *ptr, goto grow; } - node = tree->root; + node = rdxtree_entry_addr(tree->root); key = 0; shift = (height - 1) * RDXTREE_RADIX; prev = NULL; @@ -478,7 +522,7 @@ rdxtree_insert_alloc_common(struct rdxtree *tree, void *ptr, return error; } - rdxtree_node_insert(prev, index, node); + rdxtree_node_insert_node(prev, index, node); rdxtree_node_link(node, prev, index); } @@ -489,7 +533,7 @@ rdxtree_insert_alloc_common(struct rdxtree *tree, void *ptr, goto grow; key |= ((unsigned long)index << shift); - node = node->entries[index]; + node = rdxtree_entry_addr(node->entries[index]); shift -= RDXTREE_RADIX; height--; } while (height > 0); @@ -552,7 +596,7 @@ rdxtree_remove(struct rdxtree *tree, unsigned long key) if (key > rdxtree_max_key(height)) return NULL; - node = tree->root; + node = rdxtree_entry_addr(tree->root); if (height == 0) { tree->root = NULL; @@ -567,7 +611,7 @@ rdxtree_remove(struct rdxtree *tree, unsigned long key) prev = node; index = (key >> shift) & RDXTREE_RADIX_MASK; - node = node->entries[index]; + node = rdxtree_entry_addr(node->entries[index]); shift -= RDXTREE_RADIX; height--; } while (height > 0); @@ -588,7 +632,7 @@ rdxtree_lookup_common(struct rdxtree *tree, unsigned long key, int get_slot) unsigned int height, shift, index; height = tree->height; - node = tree->root; + node = rdxtree_entry_addr(tree->root); if (key > rdxtree_max_key(height)) return NULL; @@ -608,7 +652,7 @@ rdxtree_lookup_common(struct rdxtree *tree, unsigned long key, int get_slot) prev = node; index = (key >> shift) & RDXTREE_RADIX_MASK; - node = node->entries[index]; + node = rdxtree_entry_addr(node->entries[index]); shift -= RDXTREE_RADIX; height--; } while (height > 0); @@ -637,9 +681,11 @@ rdxtree_replace_slot(void **slot, void *ptr) void *old; assert(ptr != NULL); + assert(rdxtree_check_alignment(ptr)); old = *slot; assert(old != NULL); + assert(rdxtree_check_alignment(old)); *slot = ptr; return old; } @@ -652,7 +698,7 @@ rdxtree_walk(struct rdxtree *tree, struct rdxtree_node *node) if (node == NULL) { height = tree->height; - node = tree->root; + node = rdxtree_entry_addr(tree->root); while (height > 1) { node = rdxtree_node_find(node, 0, 0); |