| 1 | /* $NetBSD: ptree.c,v 1.10 2012/10/06 22:15:09 matt Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 2008 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Matt Thomas <matt@3am-software.com>. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * 1. Redistributions of source code must retain the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer. |
| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer in the |
| 17 | * documentation and/or other materials provided with the distribution. |
| 18 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 29 | * POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | #define _PT_PRIVATE |
| 33 | |
| 34 | #if defined(PTCHECK) && !defined(PTDEBUG) |
| 35 | #define PTDEBUG |
| 36 | #endif |
| 37 | |
| 38 | #if defined(_KERNEL) || defined(_STANDALONE) |
| 39 | #include <sys/param.h> |
| 40 | #include <sys/types.h> |
| 41 | #include <sys/systm.h> |
| 42 | #include <lib/libkern/libkern.h> |
| 43 | __KERNEL_RCSID(0, "$NetBSD: ptree.c,v 1.10 2012/10/06 22:15:09 matt Exp $" ); |
| 44 | #else |
| 45 | #include <stddef.h> |
| 46 | #include <stdint.h> |
| 47 | #include <limits.h> |
| 48 | #include <stdbool.h> |
| 49 | #include <string.h> |
| 50 | #ifdef PTDEBUG |
| 51 | #include <assert.h> |
| 52 | #define KASSERT(e) assert(e) |
| 53 | #else |
| 54 | #define KASSERT(e) do { } while (/*CONSTCOND*/ 0) |
| 55 | #endif |
| 56 | __RCSID("$NetBSD: ptree.c,v 1.10 2012/10/06 22:15:09 matt Exp $" ); |
| 57 | #endif /* _KERNEL || _STANDALONE */ |
| 58 | |
| 59 | #ifdef _LIBC |
| 60 | #include "namespace.h" |
| 61 | #endif |
| 62 | |
| 63 | #ifdef PTTEST |
| 64 | #include "ptree.h" |
| 65 | #else |
| 66 | #include <sys/ptree.h> |
| 67 | #endif |
| 68 | |
| 69 | /* |
| 70 | * This is an implementation of a radix / PATRICIA tree. As in a traditional |
| 71 | * patricia tree, all the data is at the leaves of the tree. An N-value |
| 72 | * tree would have N leaves, N-1 branching nodes, and a root pointer. Each |
| 73 | * branching node would have left(0) and right(1) pointers that either point |
| 74 | * to another branching node or a leaf node. The root pointer would also |
| 75 | * point to either the first branching node or a leaf node. Leaf nodes |
| 76 | * have no need for pointers. |
| 77 | * |
| 78 | * However, allocation for these branching nodes is problematic since the |
| 79 | * allocation could fail. This would cause insertions to fail for reasons |
| 80 | * beyond the user's control. So to prevent this, in this implementation |
| 81 | * each node has two identities: its leaf identity and its branch identity. |
| 82 | * Each is separate from the other. Every branch is tagged as to whether |
| 83 | * it points to a leaf or a branch. This is not an attribute of the object |
| 84 | * but of the pointer to the object. The low bit of the pointer is used as |
| 85 | * the tag to determine whether it points to a leaf or branch identity, with |
| 86 | * branch identities having the low bit set. |
| 87 | * |
| 88 | * A node's branch identity has one rule: when traversing the tree from the |
| 89 | * root to the node's leaf identity, one of the branches traversed will be via |
| 90 | * the node's branch identity. Of course, that has an exception: since to |
| 91 | * store N leaves, you need N-1 branches. That one node whose branch identity |
| 92 | * isn't used is stored as "oddman"-out in the root. |
| 93 | * |
| 94 | * Branching nodes also has a bit offset and a bit length which determines |
| 95 | * which branch slot is used. The bit length can be zero resulting in a |
| 96 | * one-way branch. This happens in two special cases: the root and |
| 97 | * interior mask nodes. |
| 98 | * |
| 99 | * To support longest match first lookups, when a mask node (one that only |
| 100 | * match the first N bits) has children who first N bits match the mask nodes, |
| 101 | * that mask node is converted from being a leaf node to being a one-way |
| 102 | * branch-node. The mask becomes fixed in position in the tree. The mask |
| 103 | * will always be the longest mask match for its descendants (unless they |
| 104 | * traverse an even longer match). |
| 105 | */ |
| 106 | |
| 107 | #define NODETOITEM(pt, ptn) \ |
| 108 | ((void *)((uintptr_t)(ptn) - (pt)->pt_node_offset)) |
| 109 | #define NODETOKEY(pt, ptn) \ |
| 110 | ((void *)((uintptr_t)(ptn) - (pt)->pt_node_offset + pt->pt_key_offset)) |
| 111 | #define ITEMTONODE(pt, ptn) \ |
| 112 | ((pt_node_t *)((uintptr_t)(ptn) + (pt)->pt_node_offset)) |
| 113 | |
| 114 | bool ptree_check(const pt_tree_t *); |
| 115 | #if PTCHECK > 1 |
| 116 | #define PTREE_CHECK(pt) ptree_check(pt) |
| 117 | #else |
| 118 | #define PTREE_CHECK(pt) do { } while (/*CONSTCOND*/ 0) |
| 119 | #endif |
| 120 | |
| 121 | static inline bool |
| 122 | ptree_matchnode(const pt_tree_t *pt, const pt_node_t *target, |
| 123 | const pt_node_t *ptn, pt_bitoff_t max_bitoff, |
| 124 | pt_bitoff_t *bitoff_p, pt_slot_t *slots_p) |
| 125 | { |
| 126 | return (*pt->pt_ops->ptto_matchnode)(NODETOKEY(pt, target), |
| 127 | (ptn != NULL ? NODETOKEY(pt, ptn) : NULL), |
| 128 | max_bitoff, bitoff_p, slots_p, pt->pt_context); |
| 129 | } |
| 130 | |
| 131 | static inline pt_slot_t |
| 132 | ptree_testnode(const pt_tree_t *pt, const pt_node_t *target, |
| 133 | const pt_node_t *ptn) |
| 134 | { |
| 135 | const pt_bitlen_t bitlen = PTN_BRANCH_BITLEN(ptn); |
| 136 | if (bitlen == 0) |
| 137 | return PT_SLOT_ROOT; /* mask or root, doesn't matter */ |
| 138 | return (*pt->pt_ops->ptto_testnode)(NODETOKEY(pt, target), |
| 139 | PTN_BRANCH_BITOFF(ptn), bitlen, pt->pt_context); |
| 140 | } |
| 141 | |
| 142 | static inline bool |
| 143 | ptree_matchkey(const pt_tree_t *pt, const void *key, |
| 144 | const pt_node_t *ptn, pt_bitoff_t bitoff, pt_bitlen_t bitlen) |
| 145 | { |
| 146 | return (*pt->pt_ops->ptto_matchkey)(key, NODETOKEY(pt, ptn), |
| 147 | bitoff, bitlen, pt->pt_context); |
| 148 | } |
| 149 | |
| 150 | static inline pt_slot_t |
| 151 | ptree_testkey(const pt_tree_t *pt, const void *key, const pt_node_t *ptn) |
| 152 | { |
| 153 | const pt_bitlen_t bitlen = PTN_BRANCH_BITLEN(ptn); |
| 154 | if (bitlen == 0) |
| 155 | return PT_SLOT_ROOT; /* mask or root, doesn't matter */ |
| 156 | return (*pt->pt_ops->ptto_testkey)(key, PTN_BRANCH_BITOFF(ptn), |
| 157 | PTN_BRANCH_BITLEN(ptn), pt->pt_context); |
| 158 | } |
| 159 | |
| 160 | static inline void |
| 161 | ptree_set_position(uintptr_t node, pt_slot_t position) |
| 162 | { |
| 163 | if (PT_LEAF_P(node)) |
| 164 | PTN_SET_LEAF_POSITION(PT_NODE(node), position); |
| 165 | else |
| 166 | PTN_SET_BRANCH_POSITION(PT_NODE(node), position); |
| 167 | } |
| 168 | |
| 169 | void |
| 170 | ptree_init(pt_tree_t *pt, const pt_tree_ops_t *ops, void *context, |
| 171 | size_t node_offset, size_t key_offset) |
| 172 | { |
| 173 | memset(pt, 0, sizeof(*pt)); |
| 174 | pt->pt_node_offset = node_offset; |
| 175 | pt->pt_key_offset = key_offset; |
| 176 | pt->pt_context = context; |
| 177 | pt->pt_ops = ops; |
| 178 | } |
| 179 | |
| 180 | typedef struct { |
| 181 | uintptr_t *id_insertp; |
| 182 | pt_node_t *id_parent; |
| 183 | uintptr_t id_node; |
| 184 | pt_slot_t id_parent_slot; |
| 185 | pt_bitoff_t id_bitoff; |
| 186 | pt_slot_t id_slot; |
| 187 | } pt_insertdata_t; |
| 188 | |
| 189 | typedef bool (*pt_insertfunc_t)(pt_tree_t *, pt_node_t *, pt_insertdata_t *); |
| 190 | |
| 191 | /* |
| 192 | * Move a branch identify from src to dst. The leaves don't care since |
| 193 | * nothing for them has changed. |
| 194 | */ |
| 195 | /*ARGSUSED*/ |
| 196 | static uintptr_t |
| 197 | ptree_move_branch(pt_tree_t * const pt, pt_node_t * const dst, |
| 198 | const pt_node_t * const src) |
| 199 | { |
| 200 | KASSERT(PTN_BRANCH_BITLEN(src) == 1); |
| 201 | /* set branch bitlen and bitoff in one step. */ |
| 202 | dst->ptn_branchdata = src->ptn_branchdata; |
| 203 | PTN_SET_BRANCH_POSITION(dst, PTN_BRANCH_POSITION(src)); |
| 204 | PTN_COPY_BRANCH_SLOTS(dst, src); |
| 205 | return PTN_BRANCH(dst); |
| 206 | } |
| 207 | |
| 208 | #ifndef PTNOMASK |
| 209 | static inline uintptr_t * |
| 210 | ptree_find_branch(pt_tree_t * const pt, uintptr_t branch_node) |
| 211 | { |
| 212 | pt_node_t * const branch = PT_NODE(branch_node); |
| 213 | pt_node_t *parent; |
| 214 | |
| 215 | for (parent = &pt->pt_rootnode;;) { |
| 216 | uintptr_t *nodep = |
| 217 | &PTN_BRANCH_SLOT(parent, ptree_testnode(pt, branch, parent)); |
| 218 | if (*nodep == branch_node) |
| 219 | return nodep; |
| 220 | if (PT_LEAF_P(*nodep)) |
| 221 | return NULL; |
| 222 | parent = PT_NODE(*nodep); |
| 223 | } |
| 224 | } |
| 225 | |
| 226 | static bool |
| 227 | ptree_insert_leaf_after_mask(pt_tree_t * const pt, pt_node_t * const target, |
| 228 | pt_insertdata_t * const id) |
| 229 | { |
| 230 | const uintptr_t target_node = PTN_LEAF(target); |
| 231 | const uintptr_t mask_node = id->id_node; |
| 232 | pt_node_t * const mask = PT_NODE(mask_node); |
| 233 | const pt_bitlen_t mask_len = PTN_MASK_BITLEN(mask); |
| 234 | |
| 235 | KASSERT(PT_LEAF_P(mask_node)); |
| 236 | KASSERT(PTN_LEAF_POSITION(mask) == id->id_parent_slot); |
| 237 | KASSERT(mask_len <= id->id_bitoff); |
| 238 | KASSERT(PTN_ISMASK_P(mask)); |
| 239 | KASSERT(!PTN_ISMASK_P(target) || mask_len < PTN_MASK_BITLEN(target)); |
| 240 | |
| 241 | if (mask_node == PTN_BRANCH_ODDMAN_SLOT(&pt->pt_rootnode)) { |
| 242 | KASSERT(id->id_parent != mask); |
| 243 | /* |
| 244 | * Nice, mask was an oddman. So just set the oddman to target. |
| 245 | */ |
| 246 | PTN_BRANCH_ODDMAN_SLOT(&pt->pt_rootnode) = target_node; |
| 247 | } else { |
| 248 | /* |
| 249 | * We need to find out who's pointing to mask's branch |
| 250 | * identity. We know that between root and the leaf identity, |
| 251 | * we must traverse the node's branch identity. |
| 252 | */ |
| 253 | uintptr_t * const mask_nodep = ptree_find_branch(pt, PTN_BRANCH(mask)); |
| 254 | KASSERT(mask_nodep != NULL); |
| 255 | KASSERT(*mask_nodep == PTN_BRANCH(mask)); |
| 256 | KASSERT(PTN_BRANCH_BITLEN(mask) == 1); |
| 257 | |
| 258 | /* |
| 259 | * Alas, mask was used as a branch. Since the mask is becoming |
| 260 | * a one-way branch, we need make target take over mask's |
| 261 | * branching responsibilities. Only then can we change it. |
| 262 | */ |
| 263 | *mask_nodep = ptree_move_branch(pt, target, mask); |
| 264 | |
| 265 | /* |
| 266 | * However, it's possible that mask's parent is itself. If |
| 267 | * that's true, update the insert point to use target since it |
| 268 | * has taken over mask's branching duties. |
| 269 | */ |
| 270 | if (id->id_parent == mask) |
| 271 | id->id_insertp = &PTN_BRANCH_SLOT(target, |
| 272 | id->id_parent_slot); |
| 273 | } |
| 274 | |
| 275 | PTN_SET_BRANCH_BITLEN(mask, 0); |
| 276 | PTN_SET_BRANCH_BITOFF(mask, mask_len); |
| 277 | |
| 278 | PTN_BRANCH_ROOT_SLOT(mask) = target_node; |
| 279 | PTN_BRANCH_ODDMAN_SLOT(mask) = PT_NULL; |
| 280 | PTN_SET_LEAF_POSITION(target, PT_SLOT_ROOT); |
| 281 | PTN_SET_BRANCH_POSITION(mask, id->id_parent_slot); |
| 282 | |
| 283 | /* |
| 284 | * Now that everything is done, to make target visible we need to |
| 285 | * change mask from a leaf to a branch. |
| 286 | */ |
| 287 | *id->id_insertp = PTN_BRANCH(mask); |
| 288 | PTREE_CHECK(pt); |
| 289 | return true; |
| 290 | } |
| 291 | |
| 292 | /*ARGSUSED*/ |
| 293 | static bool |
| 294 | ptree_insert_mask_before_node(pt_tree_t * const pt, pt_node_t * const target, |
| 295 | pt_insertdata_t * const id) |
| 296 | { |
| 297 | const uintptr_t node = id->id_node; |
| 298 | pt_node_t * const ptn = PT_NODE(node); |
| 299 | const pt_slot_t mask_len = PTN_MASK_BITLEN(target); |
| 300 | const pt_bitlen_t node_mask_len = PTN_MASK_BITLEN(ptn); |
| 301 | |
| 302 | KASSERT(PT_LEAF_P(node) || id->id_parent_slot == PTN_BRANCH_POSITION(ptn)); |
| 303 | KASSERT(PT_BRANCH_P(node) || id->id_parent_slot == PTN_LEAF_POSITION(ptn)); |
| 304 | KASSERT(PTN_ISMASK_P(target)); |
| 305 | |
| 306 | /* |
| 307 | * If the node we are placing ourself in front is a mask with the |
| 308 | * same mask length as us, return failure. |
| 309 | */ |
| 310 | if (PTN_ISMASK_P(ptn) && node_mask_len == mask_len) |
| 311 | return false; |
| 312 | |
| 313 | PTN_SET_BRANCH_BITLEN(target, 0); |
| 314 | PTN_SET_BRANCH_BITOFF(target, mask_len); |
| 315 | |
| 316 | PTN_BRANCH_SLOT(target, PT_SLOT_ROOT) = node; |
| 317 | *id->id_insertp = PTN_BRANCH(target); |
| 318 | |
| 319 | PTN_SET_BRANCH_POSITION(target, id->id_parent_slot); |
| 320 | ptree_set_position(node, PT_SLOT_ROOT); |
| 321 | |
| 322 | PTREE_CHECK(pt); |
| 323 | return true; |
| 324 | } |
| 325 | #endif /* !PTNOMASK */ |
| 326 | |
| 327 | /*ARGSUSED*/ |
| 328 | static bool |
| 329 | ptree_insert_branch_at_node(pt_tree_t * const pt, pt_node_t * const target, |
| 330 | pt_insertdata_t * const id) |
| 331 | { |
| 332 | const uintptr_t target_node = PTN_LEAF(target); |
| 333 | const uintptr_t node = id->id_node; |
| 334 | const pt_slot_t other_slot = id->id_slot ^ PT_SLOT_OTHER; |
| 335 | |
| 336 | KASSERT(PT_BRANCH_P(node) || id->id_parent_slot == PTN_LEAF_POSITION(PT_NODE(node))); |
| 337 | KASSERT(PT_LEAF_P(node) || id->id_parent_slot == PTN_BRANCH_POSITION(PT_NODE(node))); |
| 338 | KASSERT((node == pt->pt_root) == (id->id_parent == &pt->pt_rootnode)); |
| 339 | #ifndef PTNOMASK |
| 340 | KASSERT(!PTN_ISMASK_P(target) || id->id_bitoff <= PTN_MASK_BITLEN(target)); |
| 341 | #endif |
| 342 | KASSERT(node == pt->pt_root || PTN_BRANCH_BITOFF(id->id_parent) + PTN_BRANCH_BITLEN(id->id_parent) <= id->id_bitoff); |
| 343 | |
| 344 | PTN_SET_BRANCH_BITOFF(target, id->id_bitoff); |
| 345 | PTN_SET_BRANCH_BITLEN(target, 1); |
| 346 | |
| 347 | PTN_BRANCH_SLOT(target, id->id_slot) = target_node; |
| 348 | PTN_BRANCH_SLOT(target, other_slot) = node; |
| 349 | *id->id_insertp = PTN_BRANCH(target); |
| 350 | |
| 351 | PTN_SET_LEAF_POSITION(target, id->id_slot); |
| 352 | ptree_set_position(node, other_slot); |
| 353 | |
| 354 | PTN_SET_BRANCH_POSITION(target, id->id_parent_slot); |
| 355 | PTREE_CHECK(pt); |
| 356 | return true; |
| 357 | } |
| 358 | |
| 359 | static bool |
| 360 | ptree_insert_leaf(pt_tree_t * const pt, pt_node_t * const target, |
| 361 | pt_insertdata_t * const id) |
| 362 | { |
| 363 | const uintptr_t leaf_node = id->id_node; |
| 364 | pt_node_t * const leaf = PT_NODE(leaf_node); |
| 365 | #ifdef PTNOMASK |
| 366 | const bool inserting_mask = false; |
| 367 | const bool at_mask = false; |
| 368 | #else |
| 369 | const bool inserting_mask = PTN_ISMASK_P(target); |
| 370 | const bool at_mask = PTN_ISMASK_P(leaf); |
| 371 | const pt_bitlen_t leaf_masklen = PTN_MASK_BITLEN(leaf); |
| 372 | const pt_bitlen_t target_masklen = PTN_MASK_BITLEN(target); |
| 373 | #endif |
| 374 | pt_insertfunc_t insertfunc = ptree_insert_branch_at_node; |
| 375 | bool matched; |
| 376 | |
| 377 | /* |
| 378 | * In all likelyhood we are going simply going to insert a branch |
| 379 | * where this leaf is which will point to the old and new leaves. |
| 380 | */ |
| 381 | KASSERT(PT_LEAF_P(leaf_node)); |
| 382 | KASSERT(PTN_LEAF_POSITION(leaf) == id->id_parent_slot); |
| 383 | matched = ptree_matchnode(pt, target, leaf, UINT_MAX, |
| 384 | &id->id_bitoff, &id->id_slot); |
| 385 | if (__predict_false(!inserting_mask)) { |
| 386 | /* |
| 387 | * We aren't inserting a mask nor is the leaf a mask, which |
| 388 | * means we are trying to insert a duplicate leaf. Can't do |
| 389 | * that. |
| 390 | */ |
| 391 | if (!at_mask && matched) |
| 392 | return false; |
| 393 | |
| 394 | #ifndef PTNOMASK |
| 395 | /* |
| 396 | * We are at a mask and the leaf we are about to insert |
| 397 | * is at or beyond the mask, we need to convert the mask |
| 398 | * from a leaf to a one-way branch interior mask. |
| 399 | */ |
| 400 | if (at_mask && id->id_bitoff >= leaf_masklen) |
| 401 | insertfunc = ptree_insert_leaf_after_mask; |
| 402 | #endif /* PTNOMASK */ |
| 403 | } |
| 404 | #ifndef PTNOMASK |
| 405 | else { |
| 406 | /* |
| 407 | * We are inserting a mask. |
| 408 | */ |
| 409 | if (matched) { |
| 410 | /* |
| 411 | * If the leaf isn't a mask, we obviously have to |
| 412 | * insert the new mask before non-mask leaf. If the |
| 413 | * leaf is a mask, and the new node has a LEQ mask |
| 414 | * length it too needs to inserted before leaf (*). |
| 415 | * |
| 416 | * In other cases, we place the new mask as leaf after |
| 417 | * leaf mask. Which mask comes first will be a one-way |
| 418 | * branch interior mask node which has the other mask |
| 419 | * node as a child. |
| 420 | * |
| 421 | * (*) ptree_insert_mask_before_node can detect a |
| 422 | * duplicate mask and return failure if needed. |
| 423 | */ |
| 424 | if (!at_mask || target_masklen <= leaf_masklen) |
| 425 | insertfunc = ptree_insert_mask_before_node; |
| 426 | else |
| 427 | insertfunc = ptree_insert_leaf_after_mask; |
| 428 | } else if (at_mask && id->id_bitoff >= leaf_masklen) { |
| 429 | /* |
| 430 | * If the new mask has a bit offset GEQ than the leaf's |
| 431 | * mask length, convert the left to a one-way branch |
| 432 | * interior mask and make that point to the new [leaf] |
| 433 | * mask. |
| 434 | */ |
| 435 | insertfunc = ptree_insert_leaf_after_mask; |
| 436 | } else { |
| 437 | /* |
| 438 | * The new mask has a bit offset less than the leaf's |
| 439 | * mask length or if the leaf isn't a mask at all, the |
| 440 | * new mask deserves to be its own leaf so we use the |
| 441 | * default insertfunc to do that. |
| 442 | */ |
| 443 | } |
| 444 | } |
| 445 | #endif /* PTNOMASK */ |
| 446 | |
| 447 | return (*insertfunc)(pt, target, id); |
| 448 | } |
| 449 | |
| 450 | static bool |
| 451 | ptree_insert_node_common(pt_tree_t *pt, void *item) |
| 452 | { |
| 453 | pt_node_t * const target = ITEMTONODE(pt, item); |
| 454 | #ifndef PTNOMASK |
| 455 | const bool inserting_mask = PTN_ISMASK_P(target); |
| 456 | const pt_bitlen_t target_masklen = PTN_MASK_BITLEN(target); |
| 457 | #endif |
| 458 | pt_insertfunc_t insertfunc; |
| 459 | pt_insertdata_t id; |
| 460 | |
| 461 | /* |
| 462 | * If this node already exists in the tree, return failure. |
| 463 | */ |
| 464 | if (target == PT_NODE(pt->pt_root)) |
| 465 | return false; |
| 466 | |
| 467 | /* |
| 468 | * We need a leaf so we can match against. Until we get a leaf |
| 469 | * we having nothing to test against. |
| 470 | */ |
| 471 | if (__predict_false(PT_NULL_P(pt->pt_root))) { |
| 472 | PTN_BRANCH_ROOT_SLOT(&pt->pt_rootnode) = PTN_LEAF(target); |
| 473 | PTN_BRANCH_ODDMAN_SLOT(&pt->pt_rootnode) = PTN_LEAF(target); |
| 474 | PTN_SET_LEAF_POSITION(target, PT_SLOT_ROOT); |
| 475 | PTREE_CHECK(pt); |
| 476 | return true; |
| 477 | } |
| 478 | |
| 479 | id.id_bitoff = 0; |
| 480 | id.id_parent = &pt->pt_rootnode; |
| 481 | id.id_parent_slot = PT_SLOT_ROOT; |
| 482 | id.id_insertp = &PTN_BRANCH_ROOT_SLOT(id.id_parent); |
| 483 | for (;;) { |
| 484 | pt_bitoff_t branch_bitoff; |
| 485 | pt_node_t * const ptn = PT_NODE(*id.id_insertp); |
| 486 | id.id_node = *id.id_insertp; |
| 487 | |
| 488 | /* |
| 489 | * If this node already exists in the tree, return failure. |
| 490 | */ |
| 491 | if (target == ptn) |
| 492 | return false; |
| 493 | |
| 494 | /* |
| 495 | * If we hit a leaf, try to insert target at leaf. We could |
| 496 | * have inlined ptree_insert_leaf here but that would have |
| 497 | * made this routine much harder to understand. Trust the |
| 498 | * compiler to optimize this properly. |
| 499 | */ |
| 500 | if (PT_LEAF_P(id.id_node)) { |
| 501 | KASSERT(PTN_LEAF_POSITION(ptn) == id.id_parent_slot); |
| 502 | insertfunc = ptree_insert_leaf; |
| 503 | break; |
| 504 | } |
| 505 | |
| 506 | /* |
| 507 | * If we aren't a leaf, we must be a branch. Make sure we are |
| 508 | * in the slot we think we are. |
| 509 | */ |
| 510 | KASSERT(PT_BRANCH_P(id.id_node)); |
| 511 | KASSERT(PTN_BRANCH_POSITION(ptn) == id.id_parent_slot); |
| 512 | |
| 513 | /* |
| 514 | * Where is this branch? |
| 515 | */ |
| 516 | branch_bitoff = PTN_BRANCH_BITOFF(ptn); |
| 517 | |
| 518 | #ifndef PTNOMASK |
| 519 | /* |
| 520 | * If this is a one-way mask node, its offset must equal |
| 521 | * its mask's bitlen. |
| 522 | */ |
| 523 | KASSERT(!(PTN_ISMASK_P(ptn) && PTN_BRANCH_BITLEN(ptn) == 0) || PTN_MASK_BITLEN(ptn) == branch_bitoff); |
| 524 | |
| 525 | /* |
| 526 | * If we are inserting a mask, and we know that at this point |
| 527 | * all bits before the current bit offset match both the target |
| 528 | * and the branch. If the target's mask length is LEQ than |
| 529 | * this branch's bit offset, then this is where the mask needs |
| 530 | * to added to the tree. |
| 531 | */ |
| 532 | if (__predict_false(inserting_mask) |
| 533 | && (PTN_ISROOT_P(pt, id.id_parent) |
| 534 | || id.id_bitoff < target_masklen) |
| 535 | && target_masklen <= branch_bitoff) { |
| 536 | /* |
| 537 | * We don't know about the bits (if any) between |
| 538 | * id.id_bitoff and the target's mask length match |
| 539 | * both the target and the branch. If the target's |
| 540 | * mask length is greater than the current bit offset |
| 541 | * make sure the untested bits match both the target |
| 542 | * and the branch. |
| 543 | */ |
| 544 | if (target_masklen == id.id_bitoff |
| 545 | || ptree_matchnode(pt, target, ptn, target_masklen, |
| 546 | &id.id_bitoff, &id.id_slot)) { |
| 547 | /* |
| 548 | * The bits matched, so insert the mask as a |
| 549 | * one-way branch. |
| 550 | */ |
| 551 | insertfunc = ptree_insert_mask_before_node; |
| 552 | break; |
| 553 | } else if (id.id_bitoff < branch_bitoff) { |
| 554 | /* |
| 555 | * They didn't match, so create a normal branch |
| 556 | * because this mask needs to a be a new leaf. |
| 557 | */ |
| 558 | insertfunc = ptree_insert_branch_at_node; |
| 559 | break; |
| 560 | } |
| 561 | } |
| 562 | #endif /* PTNOMASK */ |
| 563 | |
| 564 | /* |
| 565 | * If we are skipping some bits, verify they match the node. |
| 566 | * If they don't match, it means we have a leaf to insert. |
| 567 | * Note that if we are advancing bit by bit, we'll skip |
| 568 | * doing matchnode and walk the tree bit by bit via testnode. |
| 569 | */ |
| 570 | if (id.id_bitoff < branch_bitoff |
| 571 | && !ptree_matchnode(pt, target, ptn, branch_bitoff, |
| 572 | &id.id_bitoff, &id.id_slot)) { |
| 573 | KASSERT(id.id_bitoff < branch_bitoff); |
| 574 | insertfunc = ptree_insert_branch_at_node; |
| 575 | break; |
| 576 | } |
| 577 | |
| 578 | /* |
| 579 | * At this point, all bits before branch_bitoff are known |
| 580 | * to match the target. |
| 581 | */ |
| 582 | KASSERT(id.id_bitoff >= branch_bitoff); |
| 583 | |
| 584 | /* |
| 585 | * Decend the tree one level. |
| 586 | */ |
| 587 | id.id_parent = ptn; |
| 588 | id.id_parent_slot = ptree_testnode(pt, target, id.id_parent); |
| 589 | id.id_bitoff += PTN_BRANCH_BITLEN(id.id_parent); |
| 590 | id.id_insertp = &PTN_BRANCH_SLOT(id.id_parent, id.id_parent_slot); |
| 591 | } |
| 592 | |
| 593 | /* |
| 594 | * Do the actual insertion. |
| 595 | */ |
| 596 | return (*insertfunc)(pt, target, &id); |
| 597 | } |
| 598 | |
| 599 | bool |
| 600 | ptree_insert_node(pt_tree_t *pt, void *item) |
| 601 | { |
| 602 | pt_node_t * const target = ITEMTONODE(pt, item); |
| 603 | |
| 604 | memset(target, 0, sizeof(*target)); |
| 605 | return ptree_insert_node_common(pt, target); |
| 606 | } |
| 607 | |
| 608 | #ifndef PTNOMASK |
| 609 | bool |
| 610 | ptree_insert_mask_node(pt_tree_t *pt, void *item, pt_bitlen_t mask_len) |
| 611 | { |
| 612 | pt_node_t * const target = ITEMTONODE(pt, item); |
| 613 | pt_bitoff_t bitoff = mask_len; |
| 614 | pt_slot_t slot; |
| 615 | |
| 616 | memset(target, 0, sizeof(*target)); |
| 617 | KASSERT(mask_len == 0 || (~PT__MASK(PTN_MASK_BITLEN) & mask_len) == 0); |
| 618 | /* |
| 619 | * Only the first <mask_len> bits can be non-zero. |
| 620 | * All other bits must be 0. |
| 621 | */ |
| 622 | if (!ptree_matchnode(pt, target, NULL, UINT_MAX, &bitoff, &slot)) |
| 623 | return false; |
| 624 | PTN_SET_MASK_BITLEN(target, mask_len); |
| 625 | PTN_MARK_MASK(target); |
| 626 | return ptree_insert_node_common(pt, target); |
| 627 | } |
| 628 | #endif /* !PTNOMASH */ |
| 629 | |
| 630 | void * |
| 631 | ptree_find_filtered_node(pt_tree_t *pt, const void *key, pt_filter_t filter, |
| 632 | void *filter_arg) |
| 633 | { |
| 634 | #ifndef PTNOMASK |
| 635 | pt_node_t *mask = NULL; |
| 636 | #endif |
| 637 | bool at_mask = false; |
| 638 | pt_node_t *ptn, *parent; |
| 639 | pt_bitoff_t bitoff; |
| 640 | pt_slot_t parent_slot; |
| 641 | |
| 642 | if (PT_NULL_P(PTN_BRANCH_ROOT_SLOT(&pt->pt_rootnode))) |
| 643 | return NULL; |
| 644 | |
| 645 | bitoff = 0; |
| 646 | parent = &pt->pt_rootnode; |
| 647 | parent_slot = PT_SLOT_ROOT; |
| 648 | for (;;) { |
| 649 | const uintptr_t node = PTN_BRANCH_SLOT(parent, parent_slot); |
| 650 | const pt_slot_t branch_bitoff = PTN_BRANCH_BITOFF(PT_NODE(node)); |
| 651 | ptn = PT_NODE(node); |
| 652 | |
| 653 | if (PT_LEAF_P(node)) { |
| 654 | #ifndef PTNOMASK |
| 655 | at_mask = PTN_ISMASK_P(ptn); |
| 656 | #endif |
| 657 | break; |
| 658 | } |
| 659 | |
| 660 | if (bitoff < branch_bitoff) { |
| 661 | if (!ptree_matchkey(pt, key, ptn, bitoff, branch_bitoff - bitoff)) { |
| 662 | #ifndef PTNOMASK |
| 663 | if (mask != NULL) |
| 664 | return NODETOITEM(pt, mask); |
| 665 | #endif |
| 666 | return NULL; |
| 667 | } |
| 668 | bitoff = branch_bitoff; |
| 669 | } |
| 670 | |
| 671 | #ifndef PTNOMASK |
| 672 | if (PTN_ISMASK_P(ptn) && PTN_BRANCH_BITLEN(ptn) == 0 |
| 673 | && (!filter |
| 674 | || (*filter)(filter_arg, NODETOITEM(pt, ptn), |
| 675 | PT_FILTER_MASK))) |
| 676 | mask = ptn; |
| 677 | #endif |
| 678 | |
| 679 | parent = ptn; |
| 680 | parent_slot = ptree_testkey(pt, key, parent); |
| 681 | bitoff += PTN_BRANCH_BITLEN(parent); |
| 682 | } |
| 683 | |
| 684 | KASSERT(PTN_ISROOT_P(pt, parent) || PTN_BRANCH_BITOFF(parent) + PTN_BRANCH_BITLEN(parent) == bitoff); |
| 685 | if (!filter || (*filter)(filter_arg, NODETOITEM(pt, ptn), at_mask ? PT_FILTER_MASK : 0)) { |
| 686 | #ifndef PTNOMASK |
| 687 | if (PTN_ISMASK_P(ptn)) { |
| 688 | const pt_bitlen_t mask_len = PTN_MASK_BITLEN(ptn); |
| 689 | if (bitoff == PTN_MASK_BITLEN(ptn)) |
| 690 | return NODETOITEM(pt, ptn); |
| 691 | if (ptree_matchkey(pt, key, ptn, bitoff, mask_len - bitoff)) |
| 692 | return NODETOITEM(pt, ptn); |
| 693 | } else |
| 694 | #endif /* !PTNOMASK */ |
| 695 | if (ptree_matchkey(pt, key, ptn, bitoff, UINT_MAX)) |
| 696 | return NODETOITEM(pt, ptn); |
| 697 | } |
| 698 | |
| 699 | #ifndef PTNOMASK |
| 700 | /* |
| 701 | * By virtue of how the mask was placed in the tree, |
| 702 | * all nodes descended from it will match it. But the bits |
| 703 | * before the mask still need to be checked and since the |
| 704 | * mask was a branch, that was done implicitly. |
| 705 | */ |
| 706 | if (mask != NULL) { |
| 707 | KASSERT(ptree_matchkey(pt, key, mask, 0, PTN_MASK_BITLEN(mask))); |
| 708 | return NODETOITEM(pt, mask); |
| 709 | } |
| 710 | #endif /* !PTNOMASK */ |
| 711 | |
| 712 | /* |
| 713 | * Nothing matched. |
| 714 | */ |
| 715 | return NULL; |
| 716 | } |
| 717 | |
| 718 | void * |
| 719 | ptree_iterate(pt_tree_t *pt, const void *item, pt_direction_t direction) |
| 720 | { |
| 721 | const pt_node_t * const target = ITEMTONODE(pt, item); |
| 722 | uintptr_t node, next_node; |
| 723 | |
| 724 | if (direction != PT_ASCENDING && direction != PT_DESCENDING) |
| 725 | return NULL; |
| 726 | |
| 727 | node = PTN_BRANCH_ROOT_SLOT(&pt->pt_rootnode); |
| 728 | if (PT_NULL_P(node)) |
| 729 | return NULL; |
| 730 | |
| 731 | if (item == NULL) { |
| 732 | pt_node_t * const ptn = PT_NODE(node); |
| 733 | if (direction == PT_ASCENDING |
| 734 | && PTN_ISMASK_P(ptn) && PTN_BRANCH_BITLEN(ptn) == 0) |
| 735 | return NODETOITEM(pt, ptn); |
| 736 | next_node = node; |
| 737 | } else { |
| 738 | #ifndef PTNOMASK |
| 739 | uintptr_t mask_node = PT_NULL; |
| 740 | #endif /* !PTNOMASK */ |
| 741 | next_node = PT_NULL; |
| 742 | while (!PT_LEAF_P(node)) { |
| 743 | pt_node_t * const ptn = PT_NODE(node); |
| 744 | pt_slot_t slot; |
| 745 | #ifndef PTNOMASK |
| 746 | if (PTN_ISMASK_P(ptn) && PTN_BRANCH_BITLEN(ptn) == 0) { |
| 747 | if (ptn == target) |
| 748 | break; |
| 749 | if (direction == PT_DESCENDING) { |
| 750 | mask_node = node; |
| 751 | next_node = PT_NULL; |
| 752 | } |
| 753 | } |
| 754 | #endif /* !PTNOMASK */ |
| 755 | slot = ptree_testnode(pt, target, ptn); |
| 756 | node = PTN_BRANCH_SLOT(ptn, slot); |
| 757 | if (direction == PT_ASCENDING) { |
| 758 | if (slot != (pt_slot_t)((1 << PTN_BRANCH_BITLEN(ptn)) - 1)) |
| 759 | next_node = PTN_BRANCH_SLOT(ptn, slot + 1); |
| 760 | } else { |
| 761 | if (slot > 0) { |
| 762 | #ifndef PTNOMASK |
| 763 | mask_node = PT_NULL; |
| 764 | #endif /* !PTNOMASK */ |
| 765 | next_node = PTN_BRANCH_SLOT(ptn, slot - 1); |
| 766 | } |
| 767 | } |
| 768 | } |
| 769 | if (PT_NODE(node) != target) |
| 770 | return NULL; |
| 771 | #ifndef PTNOMASK |
| 772 | if (PT_BRANCH_P(node)) { |
| 773 | pt_node_t *ptn = PT_NODE(node); |
| 774 | KASSERT(PTN_ISMASK_P(PT_NODE(node)) && PTN_BRANCH_BITLEN(PT_NODE(node)) == 0); |
| 775 | if (direction == PT_ASCENDING) { |
| 776 | next_node = PTN_BRANCH_ROOT_SLOT(ptn); |
| 777 | ptn = PT_NODE(next_node); |
| 778 | } |
| 779 | } |
| 780 | /* |
| 781 | * When descending, if we countered a mask node then that's |
| 782 | * we want to return. |
| 783 | */ |
| 784 | if (direction == PT_DESCENDING && !PT_NULL_P(mask_node)) { |
| 785 | KASSERT(PT_NULL_P(next_node)); |
| 786 | return NODETOITEM(pt, PT_NODE(mask_node)); |
| 787 | } |
| 788 | #endif /* !PTNOMASK */ |
| 789 | } |
| 790 | |
| 791 | node = next_node; |
| 792 | if (PT_NULL_P(node)) |
| 793 | return NULL; |
| 794 | |
| 795 | while (!PT_LEAF_P(node)) { |
| 796 | pt_node_t * const ptn = PT_NODE(node); |
| 797 | pt_slot_t slot; |
| 798 | if (direction == PT_ASCENDING) { |
| 799 | #ifndef PTNOMASK |
| 800 | if (PT_BRANCH_P(node) |
| 801 | && PTN_ISMASK_P(ptn) |
| 802 | && PTN_BRANCH_BITLEN(ptn) == 0) |
| 803 | return NODETOITEM(pt, ptn); |
| 804 | #endif /* !PTNOMASK */ |
| 805 | slot = PT_SLOT_LEFT; |
| 806 | } else { |
| 807 | slot = (1 << PTN_BRANCH_BITLEN(ptn)) - 1; |
| 808 | } |
| 809 | node = PTN_BRANCH_SLOT(ptn, slot); |
| 810 | } |
| 811 | return NODETOITEM(pt, PT_NODE(node)); |
| 812 | } |
| 813 | |
| 814 | void |
| 815 | ptree_remove_node(pt_tree_t *pt, void *item) |
| 816 | { |
| 817 | pt_node_t * const target = ITEMTONODE(pt, item); |
| 818 | const pt_slot_t leaf_slot = PTN_LEAF_POSITION(target); |
| 819 | const pt_slot_t branch_slot = PTN_BRANCH_POSITION(target); |
| 820 | pt_node_t *ptn, *parent; |
| 821 | uintptr_t node; |
| 822 | uintptr_t *removep; |
| 823 | uintptr_t *nodep; |
| 824 | pt_bitoff_t bitoff; |
| 825 | pt_slot_t parent_slot; |
| 826 | #ifndef PTNOMASK |
| 827 | bool at_mask; |
| 828 | #endif |
| 829 | |
| 830 | if (PT_NULL_P(PTN_BRANCH_ROOT_SLOT(&pt->pt_rootnode))) { |
| 831 | KASSERT(!PT_NULL_P(PTN_BRANCH_ROOT_SLOT(&pt->pt_rootnode))); |
| 832 | return; |
| 833 | } |
| 834 | |
| 835 | bitoff = 0; |
| 836 | removep = NULL; |
| 837 | nodep = NULL; |
| 838 | parent = &pt->pt_rootnode; |
| 839 | parent_slot = PT_SLOT_ROOT; |
| 840 | for (;;) { |
| 841 | node = PTN_BRANCH_SLOT(parent, parent_slot); |
| 842 | ptn = PT_NODE(node); |
| 843 | #ifndef PTNOMASK |
| 844 | at_mask = PTN_ISMASK_P(ptn); |
| 845 | #endif |
| 846 | |
| 847 | if (PT_LEAF_P(node)) |
| 848 | break; |
| 849 | |
| 850 | /* |
| 851 | * If we are at the target, then we are looking at its branch |
| 852 | * identity. We need to remember who's pointing at it so we |
| 853 | * stop them from doing that. |
| 854 | */ |
| 855 | if (__predict_false(ptn == target)) { |
| 856 | KASSERT(nodep == NULL); |
| 857 | #ifndef PTNOMASK |
| 858 | /* |
| 859 | * Interior mask nodes are trivial to get rid of. |
| 860 | */ |
| 861 | if (at_mask && PTN_BRANCH_BITLEN(ptn) == 0) { |
| 862 | PTN_BRANCH_SLOT(parent, parent_slot) = |
| 863 | PTN_BRANCH_ROOT_SLOT(ptn); |
| 864 | KASSERT(PT_NULL_P(PTN_BRANCH_ODDMAN_SLOT(ptn))); |
| 865 | PTREE_CHECK(pt); |
| 866 | return; |
| 867 | } |
| 868 | #endif /* !PTNOMASK */ |
| 869 | nodep = &PTN_BRANCH_SLOT(parent, parent_slot); |
| 870 | KASSERT(*nodep == PTN_BRANCH(target)); |
| 871 | } |
| 872 | /* |
| 873 | * We need also need to know who's pointing at our parent. |
| 874 | * After we remove ourselves from our parent, he'll only |
| 875 | * have one child and that's unacceptable. So we replace |
| 876 | * the pointer to the parent with our abadoned sibling. |
| 877 | */ |
| 878 | removep = &PTN_BRANCH_SLOT(parent, parent_slot); |
| 879 | |
| 880 | /* |
| 881 | * Descend into the tree. |
| 882 | */ |
| 883 | parent = ptn; |
| 884 | parent_slot = ptree_testnode(pt, target, parent); |
| 885 | bitoff += PTN_BRANCH_BITLEN(parent); |
| 886 | } |
| 887 | |
| 888 | /* |
| 889 | * We better have found that the leaf we are looking for is target. |
| 890 | */ |
| 891 | if (target != ptn) { |
| 892 | KASSERT(target == ptn); |
| 893 | return; |
| 894 | } |
| 895 | |
| 896 | /* |
| 897 | * If we didn't encounter target as branch, then target must be the |
| 898 | * oddman-out. |
| 899 | */ |
| 900 | if (nodep == NULL) { |
| 901 | KASSERT(PTN_BRANCH_ODDMAN_SLOT(&pt->pt_rootnode) == PTN_LEAF(target)); |
| 902 | KASSERT(nodep == NULL); |
| 903 | nodep = &PTN_BRANCH_ODDMAN_SLOT(&pt->pt_rootnode); |
| 904 | } |
| 905 | |
| 906 | KASSERT((removep == NULL) == (parent == &pt->pt_rootnode)); |
| 907 | |
| 908 | /* |
| 909 | * We have to special remove the last leaf from the root since |
| 910 | * the only time the tree can a PT_NULL node is when it's empty. |
| 911 | */ |
| 912 | if (__predict_false(PTN_ISROOT_P(pt, parent))) { |
| 913 | KASSERT(removep == NULL); |
| 914 | KASSERT(parent == &pt->pt_rootnode); |
| 915 | KASSERT(nodep == &PTN_BRANCH_ODDMAN_SLOT(&pt->pt_rootnode)); |
| 916 | KASSERT(*nodep == PTN_LEAF(target)); |
| 917 | PTN_BRANCH_ROOT_SLOT(&pt->pt_rootnode) = PT_NULL; |
| 918 | PTN_BRANCH_ODDMAN_SLOT(&pt->pt_rootnode) = PT_NULL; |
| 919 | return; |
| 920 | } |
| 921 | |
| 922 | KASSERT((parent == target) == (removep == nodep)); |
| 923 | if (PTN_BRANCH(parent) == PTN_BRANCH_SLOT(target, PTN_BRANCH_POSITION(parent))) { |
| 924 | /* |
| 925 | * The pointer to the parent actually lives in the target's |
| 926 | * branch identity. We can't just move the target's branch |
| 927 | * identity since that would result in the parent pointing |
| 928 | * to its own branch identity and that's fobidden. |
| 929 | */ |
| 930 | const pt_slot_t slot = PTN_BRANCH_POSITION(parent); |
| 931 | const pt_slot_t other_slot = slot ^ PT_SLOT_OTHER; |
| 932 | const pt_bitlen_t parent_bitlen = PTN_BRANCH_BITLEN(parent); |
| 933 | |
| 934 | KASSERT(PTN_BRANCH_BITOFF(target) < PTN_BRANCH_BITOFF(parent)); |
| 935 | |
| 936 | /* |
| 937 | * This gets so confusing. The target's branch identity |
| 938 | * points to the branch identity of the parent of the target's |
| 939 | * leaf identity: |
| 940 | * |
| 941 | * TB = { X, PB = { TL, Y } } |
| 942 | * or TB = { X, PB = { TL } } |
| 943 | * |
| 944 | * So we can't move the target's branch identity to the parent |
| 945 | * because that would corrupt the tree. |
| 946 | */ |
| 947 | if (__predict_true(parent_bitlen > 0)) { |
| 948 | /* |
| 949 | * The parent is a two-way branch. We have to have |
| 950 | * do to this chang in two steps to keep internally |
| 951 | * consistent. First step is to copy our sibling from |
| 952 | * our parent to where we are pointing to parent's |
| 953 | * branch identiy. This remove all references to his |
| 954 | * branch identity from the tree. We then simply make |
| 955 | * the parent assume the target's branching duties. |
| 956 | * |
| 957 | * TB = { X, PB = { Y, TL } } --> PB = { X, Y }. |
| 958 | * TB = { X, PB = { TL, Y } } --> PB = { X, Y }. |
| 959 | * TB = { PB = { Y, TL }, X } --> PB = { Y, X }. |
| 960 | * TB = { PB = { TL, Y }, X } --> PB = { Y, X }. |
| 961 | */ |
| 962 | PTN_BRANCH_SLOT(target, slot) = |
| 963 | PTN_BRANCH_SLOT(parent, parent_slot ^ PT_SLOT_OTHER); |
| 964 | *nodep = ptree_move_branch(pt, parent, target); |
| 965 | PTREE_CHECK(pt); |
| 966 | return; |
| 967 | } else { |
| 968 | /* |
| 969 | * If parent was a one-way branch, it must have been |
| 970 | * mask which pointed to a single leaf which we are |
| 971 | * removing. This means we have to convert the |
| 972 | * parent back to a leaf node. So in the same |
| 973 | * position that target pointed to parent, we place |
| 974 | * leaf pointer to parent. In the other position, |
| 975 | * we just put the other node from target. |
| 976 | * |
| 977 | * TB = { X, PB = { TL } } --> PB = { X, PL } |
| 978 | */ |
| 979 | KASSERT(PTN_ISMASK_P(parent)); |
| 980 | KASSERT(slot == ptree_testnode(pt, parent, target)); |
| 981 | PTN_BRANCH_SLOT(parent, slot) = PTN_LEAF(parent); |
| 982 | PTN_BRANCH_SLOT(parent, other_slot) = |
| 983 | PTN_BRANCH_SLOT(target, other_slot); |
| 984 | PTN_SET_LEAF_POSITION(parent,slot); |
| 985 | PTN_SET_BRANCH_BITLEN(parent, 1); |
| 986 | } |
| 987 | PTN_SET_BRANCH_BITOFF(parent, PTN_BRANCH_BITOFF(target)); |
| 988 | PTN_SET_BRANCH_POSITION(parent, PTN_BRANCH_POSITION(target)); |
| 989 | |
| 990 | *nodep = PTN_BRANCH(parent); |
| 991 | PTREE_CHECK(pt); |
| 992 | return; |
| 993 | } |
| 994 | |
| 995 | #ifndef PTNOMASK |
| 996 | if (__predict_false(PTN_BRANCH_BITLEN(parent) == 0)) { |
| 997 | /* |
| 998 | * Parent was a one-way branch which is changing back to a leaf. |
| 999 | * Since parent is no longer a one-way branch, it can take over |
| 1000 | * target's branching duties. |
| 1001 | * |
| 1002 | * GB = { PB = { TL } } --> GB = { PL } |
| 1003 | * TB = { X, Y } --> PB = { X, Y } |
| 1004 | */ |
| 1005 | KASSERT(PTN_ISMASK_P(parent)); |
| 1006 | KASSERT(parent != target); |
| 1007 | *removep = PTN_LEAF(parent); |
| 1008 | } else |
| 1009 | #endif /* !PTNOMASK */ |
| 1010 | { |
| 1011 | /* |
| 1012 | * Now we are the normal removal case. Since after the |
| 1013 | * target's leaf identity is removed from the its parent, |
| 1014 | * that parent will only have one decendent. So we can |
| 1015 | * just as easily replace the node that has the parent's |
| 1016 | * branch identity with the surviving node. This freeing |
| 1017 | * parent from its branching duties which means it can |
| 1018 | * take over target's branching duties. |
| 1019 | * |
| 1020 | * GB = { PB = { X, TL } } --> GB = { X } |
| 1021 | * TB = { V, W } --> PB = { V, W } |
| 1022 | */ |
| 1023 | const pt_slot_t other_slot = parent_slot ^ PT_SLOT_OTHER; |
| 1024 | uintptr_t other_node = PTN_BRANCH_SLOT(parent, other_slot); |
| 1025 | const pt_slot_t target_slot = (parent == target ? branch_slot : leaf_slot); |
| 1026 | |
| 1027 | *removep = other_node; |
| 1028 | |
| 1029 | ptree_set_position(other_node, target_slot); |
| 1030 | |
| 1031 | /* |
| 1032 | * If target's branch identity contained its leaf identity, we |
| 1033 | * have nothing left to do. We've already moved 'X' so there |
| 1034 | * is no longer anything in the target's branch identiy that |
| 1035 | * has to be preserved. |
| 1036 | */ |
| 1037 | if (parent == target) { |
| 1038 | /* |
| 1039 | * GB = { TB = { X, TL } } --> GB = { X } |
| 1040 | * TB = { X, TL } --> don't care |
| 1041 | */ |
| 1042 | PTREE_CHECK(pt); |
| 1043 | return; |
| 1044 | } |
| 1045 | } |
| 1046 | |
| 1047 | /* |
| 1048 | * If target wasn't used as a branch, then it must have been the |
| 1049 | * oddman-out of the tree (the one node that doesn't have a branch |
| 1050 | * identity). This makes parent the new oddman-out. |
| 1051 | */ |
| 1052 | if (*nodep == PTN_LEAF(target)) { |
| 1053 | KASSERT(nodep == &PTN_BRANCH_ODDMAN_SLOT(&pt->pt_rootnode)); |
| 1054 | PTN_BRANCH_ODDMAN_SLOT(&pt->pt_rootnode) = PTN_LEAF(parent); |
| 1055 | PTREE_CHECK(pt); |
| 1056 | return; |
| 1057 | } |
| 1058 | |
| 1059 | /* |
| 1060 | * Finally move the target's branching duties to the parent. |
| 1061 | */ |
| 1062 | KASSERT(PTN_BRANCH_BITOFF(parent) > PTN_BRANCH_BITOFF(target)); |
| 1063 | *nodep = ptree_move_branch(pt, parent, target); |
| 1064 | PTREE_CHECK(pt); |
| 1065 | } |
| 1066 | |
| 1067 | #ifdef PTCHECK |
| 1068 | static const pt_node_t * |
| 1069 | ptree_check_find_node2(const pt_tree_t *pt, const pt_node_t *parent, |
| 1070 | uintptr_t target) |
| 1071 | { |
| 1072 | const pt_bitlen_t slots = 1 << PTN_BRANCH_BITLEN(parent); |
| 1073 | pt_slot_t slot; |
| 1074 | |
| 1075 | for (slot = 0; slot < slots; slot++) { |
| 1076 | const uintptr_t node = PTN_BRANCH_SLOT(parent, slot); |
| 1077 | if (PTN_BRANCH_SLOT(parent, slot) == node) |
| 1078 | return parent; |
| 1079 | } |
| 1080 | for (slot = 0; slot < slots; slot++) { |
| 1081 | const uintptr_t node = PTN_BRANCH_SLOT(parent, slot); |
| 1082 | const pt_node_t *branch; |
| 1083 | if (!PT_BRANCH_P(node)) |
| 1084 | continue; |
| 1085 | branch = ptree_check_find_node2(pt, PT_NODE(node), target); |
| 1086 | if (branch != NULL) |
| 1087 | return branch; |
| 1088 | } |
| 1089 | |
| 1090 | return NULL; |
| 1091 | } |
| 1092 | |
| 1093 | static bool |
| 1094 | ptree_check_leaf(const pt_tree_t *pt, const pt_node_t *parent, |
| 1095 | const pt_node_t *ptn) |
| 1096 | { |
| 1097 | const pt_bitoff_t leaf_position = PTN_LEAF_POSITION(ptn); |
| 1098 | const pt_bitlen_t bitlen = PTN_BRANCH_BITLEN(ptn); |
| 1099 | const pt_bitlen_t mask_len = PTN_MASK_BITLEN(ptn); |
| 1100 | const uintptr_t leaf_node = PTN_LEAF(ptn); |
| 1101 | const bool is_parent_root = (parent == &pt->pt_rootnode); |
| 1102 | const bool is_mask = PTN_ISMASK_P(ptn); |
| 1103 | bool ok = true; |
| 1104 | |
| 1105 | if (is_parent_root) { |
| 1106 | ok = ok && PTN_BRANCH_ODDMAN_SLOT(parent) == leaf_node; |
| 1107 | KASSERT(ok); |
| 1108 | return ok; |
| 1109 | } |
| 1110 | |
| 1111 | if (is_mask && PTN_ISMASK_P(parent) && PTN_BRANCH_BITLEN(parent) == 0) { |
| 1112 | ok = ok && PTN_MASK_BITLEN(parent) < mask_len; |
| 1113 | KASSERT(ok); |
| 1114 | ok = ok && PTN_BRANCH_BITOFF(parent) < mask_len; |
| 1115 | KASSERT(ok); |
| 1116 | } |
| 1117 | ok = ok && PTN_BRANCH_SLOT(parent, leaf_position) == leaf_node; |
| 1118 | KASSERT(ok); |
| 1119 | ok = ok && leaf_position == ptree_testnode(pt, ptn, parent); |
| 1120 | KASSERT(ok); |
| 1121 | if (PTN_BRANCH_ODDMAN_SLOT(&pt->pt_rootnode) != leaf_node) { |
| 1122 | ok = ok && bitlen > 0; |
| 1123 | KASSERT(ok); |
| 1124 | ok = ok && ptn == ptree_check_find_node2(pt, ptn, PTN_LEAF(ptn)); |
| 1125 | KASSERT(ok); |
| 1126 | } |
| 1127 | return ok; |
| 1128 | } |
| 1129 | |
| 1130 | static bool |
| 1131 | ptree_check_branch(const pt_tree_t *pt, const pt_node_t *parent, |
| 1132 | const pt_node_t *ptn) |
| 1133 | { |
| 1134 | const bool is_parent_root = (parent == &pt->pt_rootnode); |
| 1135 | const pt_slot_t branch_slot = PTN_BRANCH_POSITION(ptn); |
| 1136 | const pt_bitoff_t bitoff = PTN_BRANCH_BITOFF(ptn); |
| 1137 | const pt_bitoff_t bitlen = PTN_BRANCH_BITLEN(ptn); |
| 1138 | const pt_bitoff_t parent_bitoff = PTN_BRANCH_BITOFF(parent); |
| 1139 | const pt_bitoff_t parent_bitlen = PTN_BRANCH_BITLEN(parent); |
| 1140 | const bool is_parent_mask = PTN_ISMASK_P(parent) && parent_bitlen == 0; |
| 1141 | const bool is_mask = PTN_ISMASK_P(ptn) && bitlen == 0; |
| 1142 | const pt_bitoff_t parent_mask_len = PTN_MASK_BITLEN(parent); |
| 1143 | const pt_bitoff_t mask_len = PTN_MASK_BITLEN(ptn); |
| 1144 | const pt_bitlen_t slots = 1 << bitlen; |
| 1145 | pt_slot_t slot; |
| 1146 | bool ok = true; |
| 1147 | |
| 1148 | ok = ok && PTN_BRANCH_SLOT(parent, branch_slot) == PTN_BRANCH(ptn); |
| 1149 | KASSERT(ok); |
| 1150 | ok = ok && branch_slot == ptree_testnode(pt, ptn, parent); |
| 1151 | KASSERT(ok); |
| 1152 | |
| 1153 | if (is_mask) { |
| 1154 | ok = ok && bitoff == mask_len; |
| 1155 | KASSERT(ok); |
| 1156 | if (is_parent_mask) { |
| 1157 | ok = ok && parent_mask_len < mask_len; |
| 1158 | KASSERT(ok); |
| 1159 | ok = ok && parent_bitoff < bitoff; |
| 1160 | KASSERT(ok); |
| 1161 | } |
| 1162 | } else { |
| 1163 | if (is_parent_mask) { |
| 1164 | ok = ok && parent_bitoff <= bitoff; |
| 1165 | } else if (!is_parent_root) { |
| 1166 | ok = ok && parent_bitoff < bitoff; |
| 1167 | } |
| 1168 | KASSERT(ok); |
| 1169 | } |
| 1170 | |
| 1171 | for (slot = 0; slot < slots; slot++) { |
| 1172 | const uintptr_t node = PTN_BRANCH_SLOT(ptn, slot); |
| 1173 | pt_bitoff_t tmp_bitoff = 0; |
| 1174 | pt_slot_t tmp_slot; |
| 1175 | ok = ok && node != PTN_BRANCH(ptn); |
| 1176 | KASSERT(ok); |
| 1177 | if (bitlen > 0) { |
| 1178 | ok = ok && ptree_matchnode(pt, PT_NODE(node), ptn, bitoff, &tmp_bitoff, &tmp_slot); |
| 1179 | KASSERT(ok); |
| 1180 | tmp_slot = ptree_testnode(pt, PT_NODE(node), ptn); |
| 1181 | ok = ok && slot == tmp_slot; |
| 1182 | KASSERT(ok); |
| 1183 | } |
| 1184 | if (PT_LEAF_P(node)) |
| 1185 | ok = ok && ptree_check_leaf(pt, ptn, PT_NODE(node)); |
| 1186 | else |
| 1187 | ok = ok && ptree_check_branch(pt, ptn, PT_NODE(node)); |
| 1188 | } |
| 1189 | |
| 1190 | return ok; |
| 1191 | } |
| 1192 | #endif /* PTCHECK */ |
| 1193 | |
| 1194 | /*ARGSUSED*/ |
| 1195 | bool |
| 1196 | ptree_check(const pt_tree_t *pt) |
| 1197 | { |
| 1198 | bool ok = true; |
| 1199 | #ifdef PTCHECK |
| 1200 | const pt_node_t * const parent = &pt->pt_rootnode; |
| 1201 | const uintptr_t node = pt->pt_root; |
| 1202 | const pt_node_t * const ptn = PT_NODE(node); |
| 1203 | |
| 1204 | ok = ok && PTN_BRANCH_BITOFF(parent) == 0; |
| 1205 | ok = ok && !PTN_ISMASK_P(parent); |
| 1206 | |
| 1207 | if (PT_NULL_P(node)) |
| 1208 | return ok; |
| 1209 | |
| 1210 | if (PT_LEAF_P(node)) |
| 1211 | ok = ok && ptree_check_leaf(pt, parent, ptn); |
| 1212 | else |
| 1213 | ok = ok && ptree_check_branch(pt, parent, ptn); |
| 1214 | #endif |
| 1215 | return ok; |
| 1216 | } |
| 1217 | |
| 1218 | bool |
| 1219 | ptree_mask_node_p(pt_tree_t *pt, const void *item, pt_bitlen_t *lenp) |
| 1220 | { |
| 1221 | const pt_node_t * const mask = ITEMTONODE(pt, item); |
| 1222 | |
| 1223 | if (!PTN_ISMASK_P(mask)) |
| 1224 | return false; |
| 1225 | |
| 1226 | if (lenp != NULL) |
| 1227 | *lenp = PTN_MASK_BITLEN(mask); |
| 1228 | |
| 1229 | return true; |
| 1230 | } |
| 1231 | |