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haproxy/include/import/cebtree-prv.h
Ben Kallus d5ca3bb3b4 IMPORT: cebtree: Replace offset calculation with offsetof to avoid UB 
This is the same as the equivalent fix in ebtree:

The C standard specifies that it's undefined behavior to dereference
NULL (even if you use & right after). The hand-rolled offsetof idiom
&(((s*)NULL)->f) is thus technically undefined. This clutters the
output of UBSan and is simple to fix: just use the real offsetof when
it's available.

This is cebtree commit 2d08958858c2b8a1da880061aed941324e20e748.
2025-11-07 07:32:58 +01:00

1768 lines
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/*
* Compact Elastic Binary Trees - internal functions and types
*
* Copyright (C) 2014-2025 Willy Tarreau - w@1wt.eu
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
/* This file MUST NOT be included by public code, it contains macros, enums
* with short names and function definitions that may clash with user code.
* It may only be included by the respective types' C files.
*/
/*
* These trees are optimized for adding the minimalest overhead to the stored
* data. This version uses the node's pointer as the key, for the purpose of
* quickly finding its neighbours.
*
* A few properties :
* - the xor between two branches of a node cannot be zero unless the two
* branches are duplicate keys
* - the xor between two nodes has *at least* the split bit set, possibly more
* - the split bit is always strictly smaller for a node than for its parent,
* which implies that the xor between the keys of the lowest level node is
* always smaller than the xor between a higher level node. Hence the xor
* between the branches of a regular leaf is always strictly larger than the
* xor of its parent node's branches if this node is different, since the
* leaf is associated with a higher level node which has at least one higher
* level branch. The first leaf doesn't validate this but is handled by the
* rules below.
* - during the descent, the node corresponding to a leaf is always visited
* before the leaf, unless it's the first inserted, nodeless leaf.
* - the first key is the only one without any node, and it has both its
* branches pointing to itself during insertion to detect it (i.e. xor==0).
* - a leaf is always present as a node on the path from the root, except for
* the inserted first key which has no node, and is recognizable by its two
* branches pointing to itself.
* - a consequence of the rules above is that a non-first leaf appearing below
* a node will necessarily have an associated node with a split bit equal to
* or greater than the node's split bit.
* - another consequence is that below a node, the split bits are different for
* each branches since both of them are already present above the node, thus
* at different levels, so their respective XOR values will be different.
* - since all nodes in a given path have a different split bit, if a leaf has
* the same split bit as its parent node, it is necessary its associated leaf
*
* When descending along the tree, it is possible to know that a search key is
* not present, because its XOR with both of the branches is stricly higher
* than the inter-branch XOR. The reason is simple : the inter-branch XOR will
* have its highest bit set indicating the split bit. Since it's the bit that
* differs between the two branches, the key cannot have it both set and
* cleared when comparing to the branch values. So xoring the key with both
* branches will emit a higher bit only when the key's bit differs from both
* branches' similar bit. Thus, the following equation :
* (XOR(key, L) > XOR(L, R)) && (XOR(key, R) > XOR(L, R))
* is only true when the key should be placed above that node. Since the key
* has a higher bit which differs from the node, either it has it set and the
* node has it clear (same for both branches), or it has it clear and the node
* has it set for both branches. For this reason it's enough to compare the key
* with any node when the equation above is true, to know if it ought to be
* present on the left or on the right side. This is useful for insertion and
* for range lookups.
*/
#ifndef _CEBTREE_PRV_H
#define _CEBTREE_PRV_H
#include <sys/types.h>
#include <inttypes.h>
#include <stddef.h>
#include <string.h>
#include "cebtree.h"
/* A few utility functions and macros that we need below */
/* This is used to test if a macro is defined and equals 1. The principle is
* that the macro is passed as a value and its value concatenated to the word
* "comma_for_one" to form a new macro name. The macro "comma_for_one1" equals
* one comma, which, once used in an argument, will shift all of them by one,
* so that we can use this to concatenate both a 1 and a 0 and always pick the
* second one.
*/
#define comma_for_one1 ,
#define _____equals_1(x, y, ...) (y)
#define ____equals_1(x, ...) _____equals_1(x, 0)
#define ___equals_1(x) ____equals_1(comma_for_one ## x 1)
#define __equals_1(x) ___equals_1(x)
/* gcc 5 and clang 3 brought __has_attribute(), which is not well documented in
* the case of gcc, but is convenient since handled at the preprocessor level.
* In both cases it's possible to test for __has_attribute() using ifdef. When
* not defined we remap this to the __has_attribute_<name> macro so that we'll
* later be able to implement on a per-compiler basis those which are missing,
* by defining __has_attribute_<name> to 1.
*/
#ifndef __has_attribute
#define __has_attribute(x) __equals_1(__has_attribute_ ## x)
#endif
/* gcc 10 and clang 3 brought __has_builtin() to test if a builtin exists.
* Just like above, if it doesn't exist, we remap it to a macro allowing us
* to define these ourselves by defining __has_builtin_<name> to 1.
*/
#ifndef __has_builtin
#define __has_builtin(x) __equals_1(__has_builtin_ ## x)
#endif
#if !defined(__GNUC__)
/* Some versions of glibc irresponsibly redefine __attribute__() to empty for
* non-gcc compilers, and as such, silently break all constructors with other
* other compilers. Let's make sure such incompatibilities are detected if any,
* or that the attribute is properly enforced.
*/
#undef __attribute__
#define __attribute__(x) __attribute__(x)
#endif
/* Define the missing __builtin_prefetch() for tcc. */
#if defined(__TINYC__) && !defined(__builtin_prefetch)
#define __builtin_prefetch(addr, ...) do { } while (0)
#endif
/* __builtin_unreachable() was added in gcc 4.5 */
#if defined(__GNUC__) && (__GNUC__ >= 5 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5))
#define __has_builtin___builtin_unreachable 1 /* make __builtin_unreachable() return 1 */
#elif !__has_builtin(__builtin_unreachable)
#define __builtin_unreachable() do { } while (1)
#endif
/* FLSNZ: find last set bit for non-zero value. "Last" here means the highest
* one. It returns a value from 1 to 32 for 1<<0 to 1<<31.
*/
#if defined(__GNUC__) && ((__GNUC__ > 4) || ((__GNUC__ == 4) && (__GNUC_MINOR__ >= 2)))
/* gcc >= 4.2 brings __builtin_clz() and __builtin_clzl(), also usable for
* non-x86. However on x86 gcc does bad stuff if not properly handled. It xors
* the bsr return with 31 and since it doesn't know how to deal with a xor
* followed by a negation, it adds two instructions when using 32-clz(). Thus
* instead we first cancel the xor using another one then add one. Even on ARM
* that provides a clz instruction, it saves one register to proceed like this.
*/
#define flsnz8(x) flsnz32((unsigned char)x)
static inline __attribute__((always_inline)) unsigned int flsnz32(unsigned int x)
{
return (__builtin_clz(x) ^ 31) + 1;
}
static inline __attribute__((always_inline)) unsigned int flsnz64(unsigned long long x)
{
return (__builtin_clzll(x) ^ 63) + 1;
}
#elif (defined(__i386__) || defined(__x86_64__)) && !defined(__atom__) /* Not gcc >= 4.2 */
/* DO NOT USE ON ATOM! The instruction is emulated and is several times slower
* than doing the math by hand.
*/
#define flsnz8(x) flsnz32((unsigned char)x)
static inline __attribute__((always_inline)) unsigned int flsnz32(unsigned int x)
{
unsigned int r;
__asm__("bsrl %1,%0\n"
: "=r" (r) : "rm" (x));
return r + 1;
}
#if defined(__x86_64__)
static inline __attribute__((always_inline)) unsigned int flsnz64(unsigned long long x)
{
unsigned long long r;
__asm__("bsrq %1,%0\n"
: "=r" (r) : "rm" (x));
return r + 1;
}
#else
static inline __attribute__((always_inline)) unsigned int flsnz64(unsigned long long x)
{
unsigned int h;
unsigned int bits = 32;
h = x >> 32;
if (!h) {
h = x;
bits = 0;
}
return flsnz32(h) + bits;
}
#endif
#else /* Neither gcc >= 4.2 nor x86, use generic code */
static inline __attribute__((always_inline)) unsigned int flsnz8(unsigned int x)
{
unsigned int ret = 0;
if (x >> 4) { x >>= 4; ret += 4; }
return ret + ((0xFFFFAA50U >> (x << 1)) & 3) + 1;
}
#define flsnz32(___a) ({ \
register unsigned int ___x, ___bits = 0; \
___x = (___a); \
if (___x & 0xffff0000) { ___x &= 0xffff0000; ___bits += 16;} \
if (___x & 0xff00ff00) { ___x &= 0xff00ff00; ___bits += 8;} \
if (___x & 0xf0f0f0f0) { ___x &= 0xf0f0f0f0; ___bits += 4;} \
if (___x & 0xcccccccc) { ___x &= 0xcccccccc; ___bits += 2;} \
if (___x & 0xaaaaaaaa) { ___x &= 0xaaaaaaaa; ___bits += 1;} \
___bits + 1; \
})
static inline __attribute__((always_inline)) unsigned int flsnz64(unsigned long long x)
{
unsigned int h;
unsigned int bits = 32;
h = x >> 32;
if (!h) {
h = x;
bits = 0;
}
return flsnz32(h) + bits;
}
#endif
#define flsnz_long(x) ((sizeof(long) > 4) ? flsnz64(x) : flsnz32(x))
#define flsnz(x) ((sizeof(x) > 4) ? flsnz64(x) : (sizeof(x) > 1) ? flsnz32(x) : flsnz8(x))
/* Compare blocks <a> and <b> byte-to-byte, from bit <ignore> to bit <len-1>.
* Return the number of equal bits between strings, assuming that the first
* <ignore> bits are already identical. It is possible to return slightly more
* than <len> bits if <len> does not stop on a byte boundary and we find exact
* bytes. Note that parts or all of <ignore> bits may be rechecked. It is only
* passed here as a hint to speed up the check.
*/
static
#if defined(__OPTIMIZE_SIZE__)
__attribute__((noinline))
#else
inline __attribute__((always_inline))
#endif
size_t equal_bits(const unsigned char *a,
const unsigned char *b,
size_t ignore, size_t len)
{
for (ignore >>= 3, a += ignore, b += ignore, ignore <<= 3;
ignore < len; ) {
unsigned char c;
a++; b++;
ignore += 8;
c = b[-1] ^ a[-1];
if (c) {
/* OK now we know that old and new differ at byte <ptr> and that <c> holds
* the bit differences. We have to find what bit is differing and report
* it as the number of identical bits. Note that low bit numbers are
* assigned to high positions in the byte, as we compare them as strings.
*/
ignore -= flsnz_long(c);
break;
}
}
return ignore;
}
/* Compare strings <a> and <b> byte-to-byte, from bit <ignore> to the last 0.
* Return the number of equal bits between strings, assuming that the first
* <ignore> bits are already identical. Note that parts or all of <ignore> bits
* may be rechecked. It is only passed here as a hint to speed up the check.
* The caller is responsible for not passing an <ignore> value larger than any
* of the two strings. However, referencing any bit from the trailing zero is
* permitted. Equal strings are reported as a negative number of bits, which
* indicates the end was reached.
*/
static
#if defined(__OPTIMIZE_SIZE__)
__attribute__((noinline))
#else
inline __attribute__((always_inline))
#endif
size_t string_equal_bits(const unsigned char *a,
const unsigned char *b,
size_t ignore)
{
unsigned char c, d;
size_t beg;
beg = ignore >> 3;
/* skip known and identical bits. We stop at the first different byte
* or at the first zero we encounter on either side.
*/
for (;; beg += 2) {
c = a[beg + 0];
d = b[beg + 0];
c ^= d;
if (__builtin_expect(c != 0, 0))
goto brk1;
if (!d)
goto same;
c = a[beg + 1];
d = b[beg + 1];
c ^= d;
if (__builtin_expect(c != 0, 0))
goto brk2;
if (!d)
goto same;
}
brk2:
beg++;
brk1:
/* OK now we know that a and b differ at byte <beg>.
* We have to find what bit is differing and report it as the number of
* identical bits. Note that low bit numbers are assigned to high positions
* in the byte, as we compare them as strings.
*/
return (beg << 3) + ((flsnz(c) - 1) ^ 7);
same:
return (size_t)-1;
}
/* pointer tagging / untagging, to turn ceb_root to ceb_node and conversely */
/* tag an untagged pointer (node -> root) */
static inline struct ceb_root *_ceb_dotag(const struct ceb_node *node, const uintptr_t tag)
{
return (struct ceb_root *)((uintptr_t)node + tag);
}
/* untag a tagged pointer (root -> node) */
static inline struct ceb_node *_ceb_untag(const struct ceb_root *node, const uintptr_t tag)
{
return (struct ceb_node *)((uintptr_t)node - tag);
}
/* clear a pointer's tag, regardless of its previous value */
static inline struct ceb_node *_ceb_clrtag(const struct ceb_root *node)
{
return (struct ceb_node *)((uintptr_t)node & ~(uintptr_t)1);
}
/* report the pointer's tag */
static inline uintptr_t _ceb_gettag(const struct ceb_root *node)
{
return (uintptr_t)node & (uintptr_t)1;
}
/* These macros are used by upper level files to create two variants of their
* exported functions:
* - one which uses sizeof(struct ceb_node) as the key offset, for nodes with
* adjacent keys ; these ones are named <pfx><sfx>(root, ...). This is
* defined when CEB_USE_BASE is defined.
* - one with an explicit key offset passed by the caller right after the
* root. This is defined when CEB_USE_OFST is defined.
* Both rely on a forced inline version with a body that immediately follows
* the declaration, so that the declaration looks like a single decorated
* function while 2 are built in practice. There are variants for the basic one
* with 0, 1 and 2 extra arguments after the root. The root and the key offset
* are always the first two arguments, and the key offset never appears in the
* first variant, it's always replaced by sizeof(struct ceb_node) in the calls
* to the inline version.
*/
#if defined(CEB_USE_BASE)
# define _CEB_DEF_BASE(x) x
#else
# define _CEB_DEF_BASE(x)
#endif
#if defined(CEB_USE_OFST)
# define _CEB_DEF_OFST(x) x
#else
# define _CEB_DEF_OFST(x)
#endif
#define CEB_FDECL2(type, pfx, sfx, type1, arg1, type2, arg2) \
_CEB_FDECL2(type, pfx, sfx, type1, arg1, type2, arg2)
#define _CEB_FDECL2(type, pfx, sfx, type1, arg1, type2, arg2) \
static inline __attribute__((always_inline)) \
type _##pfx##sfx(type1 arg1, type2 arg2); \
_CEB_DEF_BASE(type pfx##_imm##sfx(type1 arg1) { \
return _##pfx##sfx(arg1, sizeof(struct ceb_node)); \
}) \
_CEB_DEF_OFST(type pfx##_ofs##sfx(type1 arg1, type2 arg2) { \
return _##pfx##sfx(arg1, arg2); \
}) \
static inline __attribute__((always_inline)) \
type _##pfx##sfx(type1 arg1, type2 arg2)
/* function body follows */
#define CEB_FDECL3(type, pfx, sfx, type1, arg1, type2, arg2, type3, arg3) \
_CEB_FDECL3(type, pfx, sfx, type1, arg1, type2, arg2, type3, arg3)
#define _CEB_FDECL3(type, pfx, sfx, type1, arg1, type2, arg2, type3, arg3) \
static inline __attribute__((always_inline)) \
type _##pfx##sfx(type1 arg1, type2 arg2, type3 arg3); \
_CEB_DEF_BASE(type pfx##_imm##sfx(type1 arg1, type3 arg3) { \
return _##pfx##sfx(arg1, sizeof(struct ceb_node), arg3); \
}) \
_CEB_DEF_OFST(type pfx##_ofs##sfx(type1 arg1, type2 arg2, type3 arg3) { \
return _##pfx##sfx(arg1, arg2, arg3); \
}) \
static inline __attribute__((always_inline)) \
type _##pfx##sfx(type1 arg1, type2 arg2, type3 arg3)
/* function body follows */
#define CEB_FDECL4(type, pfx, sfx, type1, arg1, type2, arg2, type3, arg3, type4, arg4) \
_CEB_FDECL4(type, pfx, sfx, type1, arg1, type2, arg2, type3, arg3, type4, arg4)
#define _CEB_FDECL4(type, pfx, sfx, type1, arg1, type2, arg2, type3, arg3, type4, arg4) \
static inline __attribute__((always_inline)) \
type _##pfx##sfx(type1 arg1, type2 arg2, type3 arg3, type4 arg4); \
_CEB_DEF_BASE(type pfx##_imm##sfx(type1 arg1, type3 arg3, type4 arg4) { \
return _##pfx##sfx(arg1, sizeof(struct ceb_node), arg3, arg4); \
}) \
_CEB_DEF_OFST(type pfx##_ofs##sfx(type1 arg1, type2 arg2, type3 arg3, type4 arg4) { \
return _##pfx##sfx(arg1, arg2, arg3, arg4); \
}) \
static inline __attribute__((always_inline)) \
type _##pfx##sfx(type1 arg1, type2 arg2, type3 arg3, type4 arg4)
/* function body follows */
#define CEB_FDECL5(type, pfx, sfx, type1, arg1, type2, arg2, type3, arg3, type4, arg4, type5, arg5) \
_CEB_FDECL5(type, pfx, sfx, type1, arg1, type2, arg2, type3, arg3, type4, arg4, type5, arg5)
#define _CEB_FDECL5(type, pfx, sfx, type1, arg1, type2, arg2, type3, arg3, type4, arg4, type5, arg5) \
static inline __attribute__((always_inline)) \
type _##pfx##sfx(type1 arg1, type2 arg2, type3 arg3, type4 arg4, type5 arg5); \
_CEB_DEF_BASE(type pfx##_imm##sfx(type1 arg1, type3 arg3, type4 arg4, type5 arg5) { \
return _##pfx##sfx(arg1, sizeof(struct ceb_node), arg3, arg4, arg5); \
}) \
_CEB_DEF_OFST(type pfx##_ofs##sfx(type1 arg1, type2 arg2, type3 arg3, type4 arg4, type5 arg5) { \
return _##pfx##sfx(arg1, arg2, arg3, arg4, arg5); \
}) \
static inline __attribute__((always_inline)) \
type _##pfx##sfx(type1 arg1, type2 arg2, type3 arg3, type4 arg4, type5 arg5)
/* function body follows */
/* tree walk method: key, left, right */
enum ceb_walk_meth {
CEB_WM_FST, /* look up "first" (walk left only) */
CEB_WM_NXT, /* look up "next" (walk right once then left) */
CEB_WM_PRV, /* look up "prev" (walk left once then right) */
CEB_WM_LST, /* look up "last" (walk right only) */
/* all methods from CEB_WM_KEQ and above do have a key */
CEB_WM_KEQ, /* look up the node equal to the key */
CEB_WM_KGE, /* look up the node greater than or equal to the key */
CEB_WM_KGT, /* look up the node greater than the key */
CEB_WM_KLE, /* look up the node lower than or equal to the key */
CEB_WM_KLT, /* look up the node lower than the key */
CEB_WM_KNX, /* look up the node's key first, then find the next */
CEB_WM_KPR, /* look up the node's key first, then find the prev */
};
enum ceb_key_type {
CEB_KT_ADDR, /* the key is the node's address */
CEB_KT_U32, /* 32-bit unsigned word in key_u32 */
CEB_KT_U64, /* 64-bit unsigned word in key_u64 */
CEB_KT_MB, /* fixed size memory block in (key_u64,key_ptr), direct storage */
CEB_KT_IM, /* fixed size memory block in (key_u64,key_ptr), indirect storage */
CEB_KT_ST, /* NUL-terminated string in key_ptr, direct storage */
CEB_KT_IS, /* NUL-terminated string in key_ptr, indirect storage */
};
union ceb_key_storage {
uint32_t u32;
uint64_t u64;
unsigned long ul;
unsigned char mb[0];
unsigned char str[0];
unsigned char *ptr; /* for CEB_KT_IS */
};
/* returns the ceb_key_storage pointer for node <n> and offset <o> */
#define NODEK(n, o) ((union ceb_key_storage*)(((char *)(n)) + (o)))
/* Generic tree descent function. It must absolutely be inlined so that the
* compiler can eliminate the tests related to the various return pointers,
* which must either point to a local variable in the caller, or be NULL.
* It must not be called with an empty tree, it's the caller business to
* deal with this special case. It returns in ret_root the location of the
* pointer to the leaf (i.e. where we have to insert ourselves). The integer
* pointed to by ret_nside will contain the side the leaf should occupy at
* its own node, with the sibling being *ret_root. Note that keys for fixed-
* size arrays are passed in key_ptr with their length in key_u64. For keyless
* nodes whose address serves as the key, the pointer needs to be passed in
* key_ptr, and pxor64 will be used internally.
* The support for duplicates is advertised by ret_is_dup not being null; it
* will be filled on return with an indication whether the node belongs to a
* duplicate list or not.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_descend(struct ceb_root **root,
enum ceb_walk_meth meth,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
int *ret_nside,
struct ceb_root ***ret_root,
struct ceb_node **ret_lparent,
int *ret_lpside,
struct ceb_node **ret_nparent,
int *ret_npside,
struct ceb_node **ret_gparent,
int *ret_gpside,
struct ceb_root **ret_back,
int *ret_is_dup)
{
#if defined(__GNUC__) && (__GNUC__ >= 12) && !defined(__OPTIMIZE__)
/* Avoid a bogus warning with gcc 12 and above: it warns about negative
* memcmp() length in non-existing code paths at -O0, as reported here:
* https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114622
*/
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wstringop-overread"
#endif
struct ceb_node *node;
union ceb_key_storage *k;
struct ceb_node *gparent = NULL;
struct ceb_node *bnode = NULL;
struct ceb_node *lparent;
uint32_t pxor32 __attribute__((unused)) = ~0U; // previous xor between branches
uint64_t pxor64 __attribute__((unused)) = ~0ULL; // previous xor between branches
int gpside = 0; // side on the grand parent
long lpside = 0; // side on the leaf's parent
long brside = 0; // branch side when descending
size_t llen = 0; // left vs key matching length
size_t rlen = 0; // right vs key matching length
size_t plen = 0; // previous common len between branches
int is_leaf = 0; // set if the current node is a leaf
/* the parent will be the (possibly virtual) node so that
* &lparent->l == root, i.e. container_of(root, struct ceb_node, b[0]).
*/
lparent = (struct ceb_node *)((char *)root - offsetof(struct ceb_node, b));
gparent = lparent;
if (ret_nparent)
*ret_nparent = NULL;
if (ret_npside)
*ret_npside = 0;
/* for key-less descents we need to set the initial branch to take */
switch (meth) {
case CEB_WM_NXT:
case CEB_WM_LST:
brside = 1; // start right for next/last
break;
case CEB_WM_FST:
case CEB_WM_PRV:
default:
brside = 0; // start left for first/prev
break;
}
/* In case of deletion, we need the node's parent and side. It's
* normally discovered during the descent while comparing branches,
* but there's a case where it's not possible, it's when the root
* is the node's parent because the first node is the one we're
* looking for. So we have to perform this check here.
*/
if (meth >= CEB_WM_KEQ && ret_nparent && ret_npside) {
union ceb_key_storage *k = NODEK(_ceb_clrtag(*root), kofs);
if (((key_type == CEB_KT_MB || key_type == CEB_KT_IM) &&
(memcmp(key_ptr, ((key_type == CEB_KT_MB) ? k->mb : k->ptr), key_u64) == 0)) ||
((key_type == CEB_KT_ST || key_type == CEB_KT_IS) &&
(strcmp(key_ptr, (const void *)((key_type == CEB_KT_ST) ? k->str : k->ptr)) == 0))) {
*ret_nparent = lparent;
*ret_npside = lpside;
}
}
/* the previous xor is initialized to the largest possible inter-branch
* value so that it can never match on the first test as we want to use
* it to detect a leaf vs node. That's achieved with plen==0 for arrays
* and pxorXX==~0 for scalars.
*/
node = _ceb_clrtag(*root);
is_leaf = _ceb_gettag(*root);
if (ret_lpside) {
/* this is a deletion, benefits from prefetching */
__builtin_prefetch(node->b[0], 0);
__builtin_prefetch(node->b[1], 0);
}
while (1) {
union ceb_key_storage *lks, *rks;
struct ceb_node *ln, *rn, *next;
struct ceb_root *lr, *rr;
int next_leaf, lnl, rnl;
lr = node->b[0]; // tagged versions
rr = node->b[1];
/* get a copy of the corresponding nodes */
lnl = _ceb_gettag(lr);
ln = _ceb_clrtag(lr);
rnl = _ceb_gettag(rr);
rn = _ceb_clrtag(rr);
/* neither pointer is tagged */
k = NODEK(node, kofs);
if (is_leaf)
break;
/* Tests show that this is the most optimal location to start
* a prefetch for adjacent nodes.
*/
__builtin_prefetch(ln, 0);
__builtin_prefetch(rn, 0);
lks = NODEK(ln, kofs);
rks = NODEK(rn, kofs);
/* In the following block, we're dealing with type-specific
* operations which follow the same construct for each type:
* 1) calculate the new side for key lookups (otherwise keep
* the current side, e.g. for first/last). Doing it early
* allows the CPU to more easily predict next branches and
* is faster by ~10%. For complex bits we keep the length
* of identical bits instead of xor. We can also xor lkey
* and rkey with key and use it everywhere later but it
* doesn't seem to bring anything.
*
* 2) calculate the xor between the two sides to figure the
* split bit position. If the new split bit is before the
* previous one, we've reached a leaf: each leaf we visit
* had its node part already visited. The only way to
* distinguish them is that the inter-branch xor of the
* leaf will be the node's one, and will necessarily be
* larger than the previous node's xor if the node is
* above (we've already checked for direct descendent
* below). Said differently, if an inter-branch xor is
* strictly larger than the previous one, it necessarily
* is the one of an upper node, so what we're seeing
* cannot be the node, hence it's the leaf. The case where
* they're equal was already dealt with by the test at the
* end of the loop (node points to self). For scalar keys,
* we directly store the last xor value in pxorXX. For
* arrays and strings, instead we store the previous equal
* length.
*
* 3) for lookups, check if the looked key still has a chance
* to be below: if it has a xor with both branches that is
* larger than the xor between them, it cannot be there,
* since it means that it differs from these branches by
* at least one bit that's higher than the split bit,
* hence not common to these branches. In such cases:
* - if we're just doing a lookup, the key is not found
* and we fail.
* - if we are inserting, we must stop here and we have
* the guarantee to be above a node.
* - if we're deleting, it could be the key we were
* looking for so we have to check for it as long as
* it's still possible to keep a copy of the node's
* parent.
*/
if (key_type == CEB_KT_U32) {
uint32_t xor32; // left vs right branch xor
uint32_t kl, kr;
kl = lks->u32; kr = rks->u32;
if (meth >= CEB_WM_KEQ) {
kl ^= key_u32; kr ^= key_u32;
brside = kl >= kr;
}
xor32 = kl ^ kr;
if (meth >= CEB_WM_KEQ) {
/* let's stop if our key is not there */
if (kl > xor32 && kr > xor32)
break;
if (ret_nparent && !*ret_nparent && ret_npside) {
if (key_u32 == k->u32) {
*ret_nparent = lparent;
*ret_npside = lpside;
}
}
/* for pure lookups, no need to go down the leaf
* if we've found the key.
*/
if (!ret_root && !ret_lpside && !ret_lparent &&
!ret_gpside && !ret_gparent && !ret_back) {
if (key_u32 == k->u32)
break;
}
}
pxor32 = xor32;
}
else if (key_type == CEB_KT_U64) {
uint64_t xor64; // left vs right branch xor
uint64_t kl, kr;
kl = lks->u64; kr = rks->u64;
if (meth >= CEB_WM_KEQ) {
kl ^= key_u64; kr ^= key_u64;
brside = kl >= kr;
}
xor64 = kl ^ kr;
if (meth >= CEB_WM_KEQ) {
/* let's stop if our key is not there */
if (kl > xor64 && kr > xor64)
break;
if (ret_nparent && !*ret_nparent && ret_npside) {
if (key_u64 == k->u64) {
*ret_nparent = lparent;
*ret_npside = lpside;
}
}
/* for pure lookups, no need to go down the leaf
* if we've found the key.
*/
if (!ret_root && !ret_lpside && !ret_lparent &&
!ret_gpside && !ret_gparent && !ret_back) {
if (key_u64 == k->u64)
break;
}
}
pxor64 = xor64;
}
else if (key_type == CEB_KT_ADDR) {
uintptr_t xoraddr; // left vs right branch xor
uintptr_t kl, kr;
kl = (uintptr_t)lks; kr = (uintptr_t)rks;
if (meth >= CEB_WM_KEQ) {
kl ^= (uintptr_t)key_ptr; kr ^= (uintptr_t)key_ptr;
brside = kl >= kr;
}
xoraddr = kl ^ kr;
if (meth >= CEB_WM_KEQ) {
/* let's stop if our key is not there */
if (kl > xoraddr && kr > xoraddr)
break;
if (ret_nparent && !*ret_nparent && ret_npside) {
if ((uintptr_t)key_ptr == (uintptr_t)node) {
*ret_nparent = lparent;
*ret_npside = lpside;
}
}
/* for pure lookups, no need to go down the leaf
* if we've found the key.
*/
if (!ret_root && !ret_lpside && !ret_lparent &&
!ret_gpside && !ret_gparent && !ret_back) {
if ((uintptr_t)key_ptr == (uintptr_t)node)
break;
}
}
pxor64 = xoraddr;
}
else if (key_type == CEB_KT_MB || key_type == CEB_KT_IM) {
size_t xlen = 0; // left vs right matching length
if (meth >= CEB_WM_KEQ) {
/* measure identical lengths */
llen = equal_bits(key_ptr, (key_type == CEB_KT_MB) ? lks->mb : lks->ptr, plen, key_u64 << 3);
rlen = equal_bits(key_ptr, (key_type == CEB_KT_MB) ? rks->mb : rks->ptr, plen, key_u64 << 3);
brside = llen <= rlen;
}
xlen = equal_bits((key_type == CEB_KT_MB) ? lks->mb : lks->ptr,
(key_type == CEB_KT_MB) ? rks->mb : rks->ptr, plen, key_u64 << 3);
if (meth >= CEB_WM_KEQ) {
/* let's stop if our key is not there */
if (llen < xlen && rlen < xlen)
break;
if (ret_nparent && ret_npside && !*ret_nparent &&
((llen == key_u64 << 3) || (rlen == key_u64 << 3))) {
*ret_nparent = node;
*ret_npside = brside;
}
/* for pure lookups, no need to go down the leaf
* if we've found the key.
*/
if (!ret_root && !ret_lpside && !ret_lparent &&
!ret_gpside && !ret_gparent && !ret_back) {
if (llen == key_u64 << 3) {
node = ln;
plen = llen;
break;
}
if (rlen == key_u64 << 3) {
node = rn;
plen = rlen;
break;
}
}
}
plen = xlen;
}
else if (key_type == CEB_KT_ST || key_type == CEB_KT_IS) {
size_t xlen = 0; // left vs right matching length
if (meth >= CEB_WM_KEQ) {
/* Note that a negative length indicates an
* equal value with the final zero reached, but
* it is still needed to descend to find the
* leaf. We take that negative length for an
* infinite one, hence the uint cast.
*/
llen = string_equal_bits(key_ptr, (key_type == CEB_KT_ST) ? lks->str : lks->ptr, plen);
rlen = string_equal_bits(key_ptr, (key_type == CEB_KT_ST) ? rks->str : rks->ptr, plen);
brside = (size_t)llen <= (size_t)rlen;
if (ret_nparent && ret_npside && !*ret_nparent &&
((ssize_t)llen < 0 || (ssize_t)rlen < 0)) {
*ret_nparent = node;
*ret_npside = brside;
}
/* for pure lookups, no need to go down the leaf
* if we've found the key.
*/
if (!ret_root && !ret_lpside && !ret_lparent &&
!ret_gpside && !ret_gparent && !ret_back) {
if ((ssize_t)llen < 0) {
node = ln;
plen = llen;
break;
}
if ((ssize_t)rlen < 0) {
node = rn;
plen = rlen;
break;
}
}
}
/* the compiler cannot know this never happens and this helps it optimize the code */
if ((ssize_t)plen < 0)
__builtin_unreachable();
xlen = string_equal_bits((key_type == CEB_KT_ST) ? lks->str : lks->ptr,
(key_type == CEB_KT_ST) ? rks->str : rks->ptr, plen);
/* let's stop if our key is not there */
if (meth >= CEB_WM_KEQ && llen < xlen && rlen < xlen)
break;
plen = xlen;
}
/* shift all copies by one */
gparent = lparent;
gpside = lpside;
lparent = node;
lpside = brside;
if (brside) {
if (meth == CEB_WM_KPR || meth == CEB_WM_KLE || meth == CEB_WM_KLT)
bnode = node;
next = rn;
next_leaf = rnl;
root = &node->b[1];
/* change branch for key-less walks */
if (meth == CEB_WM_NXT)
brside = 0;
}
else {
if (meth == CEB_WM_KNX || meth == CEB_WM_KGE || meth == CEB_WM_KGT)
bnode = node;
next = ln;
next_leaf = lnl;
root = &node->b[0];
/* change branch for key-less walks */
if (meth == CEB_WM_PRV)
brside = 1;
}
if (next == node) {
/* loops over itself, it's either a leaf or the single and last list element of a dup sub-tree */
break;
}
/* let the compiler know there's no NULL in the tree */
if (!next)
__builtin_unreachable();
node = next;
is_leaf = next_leaf;
}
if (ret_is_dup) {
if (is_leaf && _ceb_gettag(node->b[0]) && _ceb_gettag(node->b[1]) &&
(_ceb_clrtag(node->b[0]) != node || _ceb_clrtag(node->b[1]) != node)) {
/* This leaf has two tagged pointers, with at least one not pointing
* to itself, it's not the nodeless leaf, it's a duplicate.
*/
*ret_is_dup = 1;
} else {
*ret_is_dup = 0;
}
}
/* here we're on the closest node from the requested value. It may be
* slightly lower (has a zero where we expected a one) or slightly
* larger has a one where we expected a zero). Thus another check is
* still deserved, depending on the matching method.
*/
/* update the pointers needed for modifications (insert, delete) */
if (ret_nside && meth >= CEB_WM_KEQ) {
switch (key_type) {
case CEB_KT_U32:
*ret_nside = key_u32 >= k->u32;
break;
case CEB_KT_U64:
*ret_nside = key_u64 >= k->u64;
break;
case CEB_KT_ADDR:
*ret_nside = (uintptr_t)key_ptr >= (uintptr_t)node;
break;
case CEB_KT_MB:
case CEB_KT_IM:
*ret_nside = (uint64_t)plen / 8 == key_u64 ||
memcmp(key_ptr + plen / 8, ((key_type == CEB_KT_MB) ? k->mb : k->ptr) + plen / 8, key_u64 - plen / 8) >= 0;
break;
case CEB_KT_ST:
case CEB_KT_IS:
*ret_nside = (ssize_t)plen < 0 ||
strcmp(key_ptr + plen / 8, (const void *)((key_type == CEB_KT_ST) ? k->str : k->ptr) + plen / 8) >= 0;
break;
}
}
if (ret_root) {
/* this node is going to be changed */
*ret_root = root;
__builtin_prefetch(root, 1);
}
/* info needed by delete */
if (ret_lpside)
*ret_lpside = lpside;
if (ret_lparent) {
/* this node is going to be changed */
*ret_lparent = lparent;
__builtin_prefetch(lparent, 1);
}
if (ret_gpside)
*ret_gpside = gpside;
if (ret_gparent)
*ret_gparent = gparent;
if (ret_back)
*ret_back = _ceb_dotag(bnode, 0);
if (meth >= CEB_WM_KEQ) {
/* For lookups, an equal value means an instant return. For insertions,
* it is the same, we want to return the previously existing value so
* that the caller can decide what to do. For deletion, we also want to
* return the pointer that's about to be deleted.
*/
if (key_type == CEB_KT_U32) {
if ((meth == CEB_WM_KEQ && k->u32 == key_u32) ||
(meth == CEB_WM_KNX && k->u32 == key_u32) ||
(meth == CEB_WM_KPR && k->u32 == key_u32) ||
(meth == CEB_WM_KGE && k->u32 >= key_u32) ||
(meth == CEB_WM_KGT && k->u32 > key_u32) ||
(meth == CEB_WM_KLE && k->u32 <= key_u32) ||
(meth == CEB_WM_KLT && k->u32 < key_u32))
return node;
}
else if (key_type == CEB_KT_U64) {
if ((meth == CEB_WM_KEQ && k->u64 == key_u64) ||
(meth == CEB_WM_KNX && k->u64 == key_u64) ||
(meth == CEB_WM_KPR && k->u64 == key_u64) ||
(meth == CEB_WM_KGE && k->u64 >= key_u64) ||
(meth == CEB_WM_KGT && k->u64 > key_u64) ||
(meth == CEB_WM_KLE && k->u64 <= key_u64) ||
(meth == CEB_WM_KLT && k->u64 < key_u64))
return node;
}
else if (key_type == CEB_KT_ADDR) {
if ((meth == CEB_WM_KEQ && (uintptr_t)node == (uintptr_t)key_ptr) ||
(meth == CEB_WM_KNX && (uintptr_t)node == (uintptr_t)key_ptr) ||
(meth == CEB_WM_KPR && (uintptr_t)node == (uintptr_t)key_ptr) ||
(meth == CEB_WM_KGE && (uintptr_t)node >= (uintptr_t)key_ptr) ||
(meth == CEB_WM_KGT && (uintptr_t)node > (uintptr_t)key_ptr) ||
(meth == CEB_WM_KLE && (uintptr_t)node <= (uintptr_t)key_ptr) ||
(meth == CEB_WM_KLT && (uintptr_t)node < (uintptr_t)key_ptr))
return node;
}
else if (key_type == CEB_KT_MB || key_type == CEB_KT_IM) {
int diff;
if ((uint64_t)plen / 8 == key_u64)
diff = 0;
else
diff = memcmp(((key_type == CEB_KT_MB) ? k->mb : k->ptr) + plen / 8, key_ptr + plen / 8, key_u64 - plen / 8);
if ((meth == CEB_WM_KEQ && diff == 0) ||
(meth == CEB_WM_KNX && diff == 0) ||
(meth == CEB_WM_KPR && diff == 0) ||
(meth == CEB_WM_KGE && diff >= 0) ||
(meth == CEB_WM_KGT && diff > 0) ||
(meth == CEB_WM_KLE && diff <= 0) ||
(meth == CEB_WM_KLT && diff < 0))
return node;
}
else if (key_type == CEB_KT_ST || key_type == CEB_KT_IS) {
int diff;
if ((ssize_t)plen < 0)
diff = 0;
else
diff = strcmp((const void *)((key_type == CEB_KT_ST) ? k->str : k->ptr) + plen / 8, key_ptr + plen / 8);
if ((meth == CEB_WM_KEQ && diff == 0) ||
(meth == CEB_WM_KNX && diff == 0) ||
(meth == CEB_WM_KPR && diff == 0) ||
(meth == CEB_WM_KGE && diff >= 0) ||
(meth == CEB_WM_KGT && diff > 0) ||
(meth == CEB_WM_KLE && diff <= 0) ||
(meth == CEB_WM_KLT && diff < 0))
return node;
}
} else if (meth == CEB_WM_FST || meth == CEB_WM_LST) {
return node;
} else if (meth == CEB_WM_PRV || meth == CEB_WM_NXT) {
return node;
}
/* lookups and deletes fail here */
/* let's return NULL to indicate the key was not found. For a lookup or
* a delete, it's a failure. For an insert, it's an invitation to the
* caller to proceed since the element is not there.
*/
return NULL;
#if defined(__GNUC__) && (__GNUC__ >= 12) && !defined(__OPTIMIZE__)
#pragma GCC diagnostic pop
#endif
}
/*
* Below are the functions that support duplicate keys (_ceb_*)
*/
/* Generic tree insertion function for trees with duplicate keys. Inserts node
* <node> into tree <tree>, with key type <key_type> and key <key_*>.
* Returns the inserted node or the one that already contains the same key.
* If <is_dup_ptr> is non-null, then duplicates are permitted and this variable
* is used to temporarily carry an internal state.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_insert(struct ceb_root **root,
struct ceb_node *node,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
int *is_dup_ptr)
{
struct ceb_root **parent;
struct ceb_node *ret;
int nside;
if (!*root) {
/* empty tree, insert a leaf only */
node->b[0] = node->b[1] = _ceb_dotag(node, 1);
*root = _ceb_dotag(node, 1);
return node;
}
ret = _ceb_descend(root, CEB_WM_KEQ, kofs, key_type, key_u32, key_u64, key_ptr, &nside, &parent, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
if (!ret) {
/* The key was not in the tree, we can insert it. Better use an
* "if" like this because the inline function above already has
* quite identifiable code paths. This reduces the code and
* optimizes it a bit.
*/
if (nside) {
node->b[1] = _ceb_dotag(node, 1);
node->b[0] = *parent;
} else {
node->b[0] = _ceb_dotag(node, 1);
node->b[1] = *parent;
}
*parent = _ceb_dotag(node, 0);
ret = node;
} else if (is_dup_ptr) {
/* The key was found. We must insert after it as the last
* element of the dups list, which means that our left branch
* will point to the key, the right one to the first dup
* (i.e. previous dup's right if it exists, otherwise ourself)
* and the parent must point to us.
*/
node->b[0] = *parent;
if (*is_dup_ptr) {
node->b[1] = _ceb_untag(*parent, 1)->b[1];
_ceb_untag(*parent, 1)->b[1] = _ceb_dotag(node, 1);
} else {
node->b[1] = _ceb_dotag(node, 1);
}
*parent = _ceb_dotag(node, 1);
ret = node;
}
return ret;
}
/* Returns the first node or NULL if not found, assuming a tree made of keys of
* type <key_type>, and optionally <key_len> for fixed-size arrays (otherwise 0).
* If the tree starts with duplicates, the first of them is returned.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_first(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint64_t key_len,
int *is_dup_ptr)
{
struct ceb_node *node;
if (!*root)
return NULL;
node = _ceb_descend((struct ceb_root **)root, CEB_WM_FST, kofs, key_type, 0, key_len, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
if (node && is_dup_ptr && *is_dup_ptr) {
/* on a duplicate, the first node is right->left and it's a leaf */
node = _ceb_untag(_ceb_untag(node->b[1], 1)->b[0], 1);
}
return node;
}
/* Returns the last node or NULL if not found, assuming a tree made of keys of
* type <key_type>, and optionally <key_len> for fixed-size arrays (otherwise 0).
* If the tree ends with duplicates, the last of them is returned.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_last(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint64_t key_len,
int *is_dup_ptr)
{
if (!*root)
return NULL;
/* note for duplicates: the current scheme always returns the last one by default */
return _ceb_descend((struct ceb_root **)root, CEB_WM_LST, kofs, key_type, 0, key_len, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
}
/* Searches in the tree <root> made of keys of type <key_type>, for the next
* node after the one containing the key <key_*>. Returns NULL if not found.
* It's up to the caller to pass the current node's key in <key_*>. The
* approach consists in looking up that node first, recalling the last time a
* left turn was made, and returning the first node along the right branch at
* that fork.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_next_unique(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
int *is_dup_ptr)
{
struct ceb_root *restart;
if (!*root)
return NULL;
if (!_ceb_descend((struct ceb_root **)root, CEB_WM_KNX, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &restart, is_dup_ptr))
return NULL;
if (!restart)
return NULL;
return _ceb_descend(&restart, CEB_WM_NXT, kofs, key_type, 0, key_u64, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
}
/* Searches in the tree <root> made of keys of type <key_type>, for the prev
* node before the one containing the key <key_*>. Returns NULL if not found.
* It's up to the caller to pass the current node's key in <key_*>. The
* approach consists in looking up that node first, recalling the last time a
* right turn was made, and returning the last node along the left branch at
* that fork.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_prev_unique(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
int *is_dup_ptr)
{
struct ceb_root *restart;
if (!*root)
return NULL;
if (!_ceb_descend((struct ceb_root **)root, CEB_WM_KPR, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &restart, is_dup_ptr))
return NULL;
if (!restart)
return NULL;
return _ceb_descend(&restart, CEB_WM_PRV, kofs, key_type, 0, key_u64, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
}
/* Searches in the tree <root> made of keys of type <key_type>, for the next
* node after <from> also containing key <key_*>. Returns NULL if not found.
* It's up to the caller to pass the current node's key in <key_*>.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_next_dup(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
const struct ceb_node *from)
{
struct ceb_node *node;
int is_dup;
if (!*root)
return NULL;
node = _ceb_descend((struct ceb_root **)root, CEB_WM_KNX, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &is_dup);
if (!node)
return NULL;
/* Normally at this point, if node != from, we've found a node that
* differs from the one we're starting from, which indicates that
* the starting point belongs to a dup list and is not the last one.
* We must then visit the other members. We cannot navigate from the
* regular leaf node (the first one) but we can easily verify if we're
* on that one by checking if it's node->b[1]->b[0], in which case we
* jump to node->b[1]. Otherwise we take from->b[1].
*/
if (node != from) {
if (_ceb_untag(node->b[1], 1)->b[0] == _ceb_dotag(from, 1))
return _ceb_untag(node->b[1], 1);
else
return _ceb_untag(from->b[1], 1);
}
/* there's no other dup here */
return NULL;
}
/* Searches in the tree <root> made of keys of type <key_type>, for the prev
* node before <from> also containing key <key_*>. Returns NULL if not found.
* It's up to the caller to pass the current node's key in <key_*>.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_prev_dup(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
const struct ceb_node *from)
{
struct ceb_node *node;
int is_dup;
if (!*root)
return NULL;
node = _ceb_descend((struct ceb_root **)root, CEB_WM_KPR, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &is_dup);
if (!node)
return NULL;
/* Here we have several possibilities:
* - from == node => we've found our node. It may be a unique node,
* or the last one of a dup series. We'll sort that out thanks to
* is_dup, and if it's a dup, we'll use node->b[0].
* - from is not the first dup, so we haven't visited them all yet,
* hence we visit node->b[0] to switch to the previous dup.
* - from is the first dup so we've visited them all.
*/
if (is_dup && (node == from || _ceb_untag(node->b[1], 1)->b[0] != _ceb_dotag(from, 1)))
return _ceb_untag(from->b[0], 1);
/* there's no other dup here */
return NULL;
}
/* Searches in the tree <root> made of keys of type <key_type>, for the next
* node after <from> which contains key <key_*>. Returns NULL if not found.
* It's up to the caller to pass the current node's key in <key_*>. The
* approach consists in looking up that node first, recalling the last time a
* left turn was made, and returning the first node along the right branch at
* that fork. In case the current node belongs to a duplicate list, all dups
* will be visited in insertion order prior to jumping to different keys.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_next(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
const struct ceb_node *from,
int *is_dup_ptr)
{
struct ceb_root *restart;
struct ceb_node *node;
if (!*root)
return NULL;
node = _ceb_descend((struct ceb_root **)root, CEB_WM_KNX, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &restart, is_dup_ptr);
if (!node)
return NULL;
/* Normally at this point, if node != from, we've found a node that
* differs from the one we're starting from, which indicates that
* the starting point belongs to a dup list and is not the last one.
* We must then visit the other members. We cannot navigate from the
* regular leaf node (the first one) but we can easily verify if we're
* on that one by checking if it's _ceb_untag(node->b[1], 0)->b[0], in which case we
* jump to node->b[1]. Otherwise we take from->b[1].
*/
if (node != from) {
if (_ceb_untag(node->b[1], 1)->b[0] == _ceb_dotag(from, 1))
return _ceb_untag(node->b[1], 1);
else
return _ceb_untag(from->b[1], 1);
}
/* Here the looked up node was found (node == from) and we can look up
* the next unique one if any.
*/
if (!restart)
return NULL;
/* this look up will stop on the topmost dup in a sub-tree which is
* also the last one. Thanks to restart we know that this entry exists.
*/
node = _ceb_descend(&restart, CEB_WM_NXT, kofs, key_type, 0, key_u64, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
if (node && is_dup_ptr && *is_dup_ptr) {
/* on a duplicate, the first node is right->left and it's a leaf */
node = _ceb_untag(_ceb_untag(node->b[1], 1)->b[0], 1);
}
return node;
}
/* Searches in the tree <root> made of keys of type <key_type>, for the prev
* node before the one containing the key <key_*>. Returns NULL if not found.
* It's up to the caller to pass the current node's key in <key_*>. The
* approach consists in looking up that node first, recalling the last time a
* right turn was made, and returning the last node along the left branch at
* that fork. In case the current node belongs to a duplicate list, all dups
* will be visited in reverse insertion order prior to jumping to different
* keys.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_prev(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
const struct ceb_node *from,
int *is_dup_ptr)
{
struct ceb_root *restart;
struct ceb_node *node;
if (!*root)
return NULL;
node = _ceb_descend((struct ceb_root **)root, CEB_WM_KPR, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &restart, is_dup_ptr);
if (!node)
return NULL;
/* Here we have several possibilities:
* - from == node => we've found our node. It may be a unique node,
* or the last one of a dup series. We'll sort that out thanks to
* is_dup, and if it's a dup, we'll use node->b[0].
* - from is not the first dup, so we haven't visited them all yet,
* hence we visit node->b[0] to switch to the previous dup.
* - from is the first dup so we've visited them all, we now need
* to jump to the previous unique value.
*/
if (is_dup_ptr && *is_dup_ptr && (node == from || _ceb_untag(node->b[1], 1)->b[0] != _ceb_dotag(from, 1)))
return _ceb_untag(from->b[0], 1);
/* look up the previous unique entry */
if (!restart)
return NULL;
/* Note that the descent stops on the last dup which is the one we want */
return _ceb_descend(&restart, CEB_WM_PRV, kofs, key_type, 0, key_u64, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
}
/* Searches in the tree <root> made of keys of type <key_type>, for the first
* node containing the key <key_*>. Returns NULL if not found.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_lookup(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
int *is_dup_ptr)
{
struct ceb_node *ret;
if (!*root)
return NULL;
ret = _ceb_descend((struct ceb_root **)root, CEB_WM_KEQ, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
if (ret && is_dup_ptr && *is_dup_ptr) {
/* on a duplicate, the first node is right->left and it's a leaf */
ret = _ceb_untag(_ceb_untag(ret->b[1], 1)->b[0], 1);
}
return ret;
}
/* Searches in the tree <root> made of keys of type <key_type>, for the last
* node containing the key <key_*> or the highest one that's lower than it.
* Returns NULL if not found.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_lookup_le(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
int *is_dup_ptr)
{
struct ceb_node *ret = NULL;
struct ceb_root *restart;
if (!*root)
return NULL;
/* note that for duplicates, we already find the last one */
ret = _ceb_descend((struct ceb_root **)root, CEB_WM_KLE, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &restart, is_dup_ptr);
if (ret)
return ret;
if (!restart)
return NULL;
return _ceb_descend(&restart, CEB_WM_PRV, kofs, key_type, 0, key_u64, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
}
/* Searches in the tree <root> made of keys of type <key_type>, for the last
* node containing the greatest key that is strictly lower than <key_*>.
* Returns NULL if not found. It's very similar to next() except that the
* looked up value doesn't need to exist.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_lookup_lt(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
int *is_dup_ptr)
{
struct ceb_node *ret = NULL;
struct ceb_root *restart;
if (!*root)
return NULL;
/* note that for duplicates, we already find the last one */
ret = _ceb_descend((struct ceb_root **)root, CEB_WM_KLT, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &restart, is_dup_ptr);
if (ret)
return ret;
if (!restart)
return NULL;
return _ceb_descend(&restart, CEB_WM_PRV, kofs, key_type, 0, key_u64, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
}
/* Searches in the tree <root> made of keys of type <key_type>, for the first
* node containing the key <key_*> or the smallest one that's greater than it.
* Returns NULL if not found. If <is_dup_ptr> is non-null, then duplicates are
* permitted and this variable is used to temporarily carry an internal state.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_lookup_ge(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
int *is_dup_ptr)
{
struct ceb_node *ret = NULL;
struct ceb_root *restart;
if (!*root)
return NULL;
ret = _ceb_descend((struct ceb_root **)root, CEB_WM_KGE, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &restart, is_dup_ptr);
if (!ret) {
if (!restart)
return NULL;
ret = _ceb_descend(&restart, CEB_WM_NXT, kofs, key_type, 0, key_u64, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
}
if (ret && is_dup_ptr && *is_dup_ptr) {
/* on a duplicate, the first node is right->left and it's a leaf */
ret = _ceb_untag(_ceb_untag(ret->b[1], 1)->b[0], 1);
}
return ret;
}
/* Searches in the tree <root> made of keys of type <key_type>, for the first
* node containing the lowest key that is strictly greater than <key_*>. Returns
* NULL if not found. It's very similar to prev() except that the looked up
* value doesn't need to exist. If <is_dup_ptr> is non-null, then duplicates are
* permitted and this variable is used to temporarily carry an internal state.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_lookup_gt(struct ceb_root *const *root,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
int *is_dup_ptr)
{
struct ceb_node *ret = NULL;
struct ceb_root *restart;
if (!*root)
return NULL;
ret = _ceb_descend((struct ceb_root **)root, CEB_WM_KGT, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, &restart, is_dup_ptr);
if (!ret) {
if (!restart)
return NULL;
ret = _ceb_descend(&restart, CEB_WM_NXT, kofs, key_type, 0, key_u64, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, is_dup_ptr);
}
if (ret && is_dup_ptr && *is_dup_ptr) {
/* on a duplicate, the first node is right->left and it's a leaf */
ret = _ceb_untag(_ceb_untag(ret->b[1], 1)->b[0], 1);
}
return ret;
}
/* Searches in the tree <root> made of keys of type <key_type>, for the node
* that contains the key <key_*>, and deletes it. If <node> is non-NULL, a
* check is performed and the node found is deleted only if it matches. The
* found node is returned in any case, otherwise NULL if not found. A deleted
* node is detected since it has b[0]==NULL, which this functions also clears
* after operation. The function is idempotent, so it's safe to attempt to
* delete an already deleted node (NULL is returned in this case since the node
* was not in the tree). If <is_dup_ptr> is non-null, then duplicates are
* permitted and this variable is used to temporarily carry an internal state.
*/
static inline __attribute__((always_inline))
struct ceb_node *_ceb_delete(struct ceb_root **root,
struct ceb_node *node,
ptrdiff_t kofs,
enum ceb_key_type key_type,
uint32_t key_u32,
uint64_t key_u64,
const void *key_ptr,
int *is_dup_ptr)
{
struct ceb_node *lparent, *nparent, *gparent;
int lpside, npside, gpside;
struct ceb_node *ret = NULL;
if (node && !node->b[0]) {
/* NULL on a branch means the node is not in the tree */
return NULL;
}
if (!*root) {
/* empty tree, the node cannot be there */
goto done;
}
ret = _ceb_descend(root, CEB_WM_KEQ, kofs, key_type, key_u32, key_u64, key_ptr, NULL, NULL,
&lparent, &lpside, &nparent, &npside, &gparent, &gpside, NULL, is_dup_ptr);
if (!ret) {
/* key not found */
goto done;
}
if (is_dup_ptr && *is_dup_ptr) {
/* the node to be deleted belongs to a dup sub-tree whose ret
* is the last. The possibilities here are:
* 1) node==NULL => unspecified, we delete the first one,
* which is the tree leaf. The tree node (if it exists)
* is replaced by the first dup. There's nothing else to
* change.
* 2) node is the tree leaf. The tree node (if it exists)
* is replaced by the first dup.
* 3) node is a dup. We just delete the dup.
* In order to delete a dup, there are 4 cases:
* a) node==last and there's a single dup, it's this one
* -> *parent = node->b[0];
* b) node==last and there's another dup:
* -> *parent = node->b[0];
* node->b[0]->b[1] = node->b[1];
* (or (*parent)->b[1] = node->b[1] covers a and b)
* c) node==first != last:
* -> node->b[1]->b[0] = node->b[0];
* last->b[1] = node->b[1];
* (or (*parent)->b[1] = node->b[1] covers a,b,c)
* d) node!=first && !=last:
* -> node->b[1]->b[0] = node->b[0];
* node->b[0]->b[1] = node->b[1];
* a,b,c,d can be simplified as:
* ((node == first) ? last : node->b[0])->b[1] = node->b[1];
* *((node == last) ? parent : &node->b[1]->b[0]) = node->b[0];
*/
struct ceb_node *first, *last;
last = ret;
first = _ceb_untag(last->b[1], 1);
/* cases 1 and 2 below */
if (!node || node == _ceb_untag(first->b[0], 1)) {
/* node unspecified or the first, remove the leaf and
* convert the first entry to it.
*/
ret = _ceb_untag(first->b[0], 1); // update return node
last->b[1] = first->b[1]; // new first (remains OK if last==first)
if (ret->b[0] != _ceb_dotag(ret, 1) || ret->b[1] != _ceb_dotag(ret, 1)) {
/* not the nodeless leaf, a node exists, put it
* on the first and update its parent.
*/
first->b[0] = ret->b[0];
first->b[1] = ret->b[1];
nparent->b[npside] = _ceb_dotag(first, 0);
}
else {
/* first becomes the nodeless leaf since we only keep its leaf */
first->b[0] = first->b[1] = _ceb_dotag(first, 1);
}
/* first becomes a leaf, it must be tagged */
if (last != first)
_ceb_untag(last->b[1], 1)->b[0] = _ceb_dotag(first, 1);
/* done */
} else {
/* case 3: the node to delete is a dup, we only have to
* manipulate the list.
*/
ret = node;
((node == first) ? last : _ceb_untag(node->b[0], 1))->b[1] = node->b[1];
*((node == last) ? &lparent->b[lpside] : &_ceb_untag(node->b[1], 1)->b[0]) = node->b[0];
/* done */
}
goto mark_and_leave;
}
/* ok below the returned value is a real leaf, we have to adjust the tree */
if (ret == node || !node) {
if (&lparent->b[0] == root) {
/* there was a single entry, this one, so we're just
* deleting the nodeless leaf.
*/
*root = NULL;
goto mark_and_leave;
}
/* then we necessarily have a gparent */
gparent->b[gpside] = lparent->b[!lpside];
if (lparent == ret) {
/* we're removing the leaf and node together, nothing
* more to do.
*/
goto mark_and_leave;
}
if (ret->b[0] == ret->b[1]) {
/* we're removing the node-less item, the parent will
* take this role.
*/
lparent->b[0] = lparent->b[1] = _ceb_dotag(lparent, 1);
goto mark_and_leave;
}
/* more complicated, the node was split from the leaf, we have
* to find a spare one to switch it. The parent node is not
* needed anymore so we can reuse it.
*/
lparent->b[0] = ret->b[0];
lparent->b[1] = ret->b[1];
nparent->b[npside] = _ceb_dotag(lparent, 0);
mark_and_leave:
/* now mark the node as deleted */
ret->b[0] = NULL;
}
done:
return ret;
}
//#if defined(CEB_ENABLE_DUMP)
/* The dump functions are in cebtree-dbg.c */
void ceb_imm_default_dump_root(ptrdiff_t kofs, enum ceb_key_type key_type, struct ceb_root *const *root, const void *ctx, int sub);
void ceb_imm_default_dump_node(ptrdiff_t kofs, enum ceb_key_type key_type, const struct ceb_node *node, int level, const void *ctx, int sub);
void ceb_imm_default_dump_dups(ptrdiff_t kofs, enum ceb_key_type key_type, const struct ceb_node *node, int level, const void *ctx, int sub);
void ceb_imm_default_dump_leaf(ptrdiff_t kofs, enum ceb_key_type key_type, const struct ceb_node *node, int level, const void *ctx, int sub);
const struct ceb_node *ceb_imm_default_dump_tree(ptrdiff_t kofs, enum ceb_key_type key_type, struct ceb_root *const *root,
uint64_t pxor, const void *last, int level, const void *ctx, int sub,
void (*root_dump)(ptrdiff_t kofs, enum ceb_key_type key_type, struct ceb_root *const *root, const void *ctx, int sub),
void (*node_dump)(ptrdiff_t kofs, enum ceb_key_type key_type, const struct ceb_node *node, int level, const void *ctx, int sub),
void (*dups_dump)(ptrdiff_t kofs, enum ceb_key_type key_type, const struct ceb_node *node, int level, const void *ctx, int sub),
void (*leaf_dump)(ptrdiff_t kofs, enum ceb_key_type key_type, const struct ceb_node *node, int level, const void *ctx, int sub));
//#endif /* CEB_ENABLE_DUMP */
#endif /* _CEBTREE_PRV_H */
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