kc3-lang/kc3/libkc3/skiplist.c.in
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Hash : 1ae6ad0e
Author :
Thomas de Grivel
Date : 2024-07-15T19:59:52
rename c3 to kc3, fix update_source, configure, build
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libkc3/skiplist.c.in
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/* kc3 * Copyright 2022,2023,2024 kmx.io <contact@kmx.io> * * Permission is hereby granted to use this software granted the above * copyright notice and this permission paragraph are included in all * copies and substantial portions of this software. * * THIS SOFTWARE IS PROVIDED "AS-IS" WITHOUT ANY GUARANTEE OF * PURPOSE AND PERFORMANCE. IN NO EVENT WHATSOEVER SHALL THE * AUTHOR BE CONSIDERED LIABLE FOR THE USE AND PERFORMANCE OF * THIS SOFTWARE. */ #include "alloc.h" #include "assert.h" #include "compare.h" #include "_NAME$.h" #include "skiplist_node___NAME$.h" #include "skiplist___NAME$.h" #include "u32.h" #include "u64.h" /* Random height ------------- ∀ U ∈ ℕ : 1 < U ∀ n ∈ ℕ* ∀ r ∈ ℕ : r ≤ n ∀ random : ℕ* ⟶ ℕ random(n) ∈ [0..n-1] ∀ i ∈ [0..n-1], P(random(n) = i) = n⁻¹ (i) Qᵣ := random(Uⁿ) < Uⁿ⁻ʳ (i) ⇒ P(random(n) < v) = ∑ᵢ₌₀ᵛ⁻¹ P(random(n) = i) ⇒ P(random(n) < v) = v . n⁻¹ (ii) ⇒ P(random(Uⁿ) < Uⁿ⁻ʳ) = Uⁿ⁻ʳ . (Uⁿ)⁻¹ ⇔ P(Qᵣ) = U⁻ʳ (iii) P(Qₙ) = P(random(Uⁿ) < U⁰) = P(random(Uⁿ) < 1) = P(random(Uⁿ) = 0) = U⁻ⁿ R := maxᵣ(Qᵣ) = maxᵣ(random(Uⁿ) < Uⁿ⁻ʳ) = maxᵣ(random(Uⁿ) + 1 ≤ Uⁿ⁻ʳ) = maxᵣ(logᵤ(random(Uⁿ) + 1) ≤ n - r) = maxᵣ(⌈logᵤ(random(Uⁿ) + 1)⌉ ≤ n - r) = maxᵣ(r ≤ n - ⌈logᵤ(random(Uⁿ) + 1)⌉) = n - ⌈logᵤ(random(Uⁿ) + 1)⌉ (iv) 0 ≤ random(Uⁿ) < Uⁿ ⇔ 1 ≤ random(Uⁿ)+1 ≤ Uⁿ ⇔ logᵤ(1) ≤ logᵤ(random(Uⁿ)+1) ≤ logᵤ(Uⁿ) ⇔ 0 ≤ ⌈logᵤ(random(Uⁿ)+1)⌉ ≤ n ⇔ -n ≤ -⌈logᵤ(random(Uⁿ)+1)⌉ ≤ 0 ⇔ 0 ≤ n - ⌈logᵤ(random(Uⁿ)+1)⌉ ≤ n ⇔ 0 ≤ R ≤ n (v) */ void skiplist_clean___NAME$ (s_skiplist___NAME$ *skiplist) { s_skiplist_node___NAME$ *node; assert(skiplist); assert(skiplist->head); while ((node = SKIPLIST_NODE_NEXT___NAME$(skiplist->head, 0))) skiplist_remove___NAME$(skiplist, node->_NAME$); skiplist_node_delete___NAME$(skiplist->head); } void skiplist_delete___NAME$ (s_skiplist___NAME$ *skiplist) { assert(skiplist); skiplist_clean___NAME$(skiplist); free(skiplist); } s_skiplist_node___NAME$ * skiplist_find___NAME$ (s_skiplist___NAME$ *skiplist, const _TYPE$ _NAME$) { s_skiplist_node___NAME$ *node = skiplist->head; u8 level = node->height; while (level--) { s_skiplist_node___NAME$ *n = node; s8 c = -1; while (n && (c = skiplist->compare(_NAME$, n->_NAME$)) > 0) n = SKIPLIST_NODE_NEXT___NAME$(n, level); if (c == 0) return n; } return NULL; } static s_skiplist___NAME$ * skiplist_height_table_init___NAME$ (s_skiplist___NAME$ *skiplist, f64 spacing) { t_skiplist_height *height_table; u8 h; f128 w = spacing; f128 end = w; height_table = SKIPLIST_HEIGHT_TABLE___NAME$(skiplist); for (h = 0; h < skiplist->max_height; h++) { w *= spacing; end += w; if (end > (f128) SKIPLIST_HEIGHT_MAX) return NULL; height_table[h] = end; } return skiplist; } s_skiplist___NAME$ * skiplist_init___NAME$ (s_skiplist___NAME$ *skiplist, u8 max_height, f64 spacing) { assert(skiplist); skiplist->max_height = max_height; skiplist_height_table_init___NAME$(skiplist, spacing); skiplist->head = skiplist_node_new___NAME$(NULL, max_height); if (! skiplist->head) return NULL; skiplist->compare = compare__NAME$; skiplist->length = 0; return skiplist; } s_skiplist_node___NAME$ * skiplist_insert___NAME$ (s_skiplist___NAME$ *skiplist, const _TYPE$ _NAME$) { s_skiplist_node___NAME$ *pred; s_skiplist_node___NAME$ *next; uw height; s_skiplist_node___NAME$ *node; pred = skiplist_pred___NAME$(skiplist, _NAME$); next = SKIPLIST_NODE_NEXT___NAME$(pred, 0); next = SKIPLIST_NODE_NEXT___NAME$(next, 0); if (next && skiplist->compare(_NAME$, next->_NAME$) == 0) return next; height = skiplist_random_height___NAME$(skiplist); node = skiplist_node_new___NAME$(_NAME$, height); skiplist_node_insert___NAME$(node, pred); skiplist->length++; skiplist_node_delete___NAME$(pred); return node; } s_skiplist___NAME$ * skiplist_new___NAME$ (u8 max_height, f64 spacing) { s_skiplist___NAME$ *skiplist; skiplist = alloc(SKIPLIST_SIZE___NAME$(max_height)); if (! skiplist) return NULL; if (! skiplist_init___NAME$(skiplist, max_height, spacing)) { free(skiplist); return NULL; } return skiplist; } s_skiplist_node___NAME$ * skiplist_pred___NAME$ (s_skiplist___NAME$ *skiplist, const _TYPE$ _NAME$) { int level; s_skiplist_node___NAME$ *pred; s_skiplist_node___NAME$ *n; s_skiplist_node___NAME$ *node; assert(skiplist); level = skiplist->max_height; pred = skiplist_node_new___NAME$(NULL, skiplist->max_height); if (! pred) return NULL; node = skiplist->head; while (level--) { n = node; while (n && skiplist->compare(_NAME$, n->_NAME$) > 0) { node = n; n = SKIPLIST_NODE_NEXT___NAME$(node, level); } SKIPLIST_NODE_NEXT___NAME$(pred, level) = node; } return pred; } u8 skiplist_random_height___NAME$ (s_skiplist___NAME$ *skiplist) { u16 height; const t_skiplist_height *height_table; sw i; u64 j; sw max; t_skiplist_height k; assert(skiplist); assert(skiplist->max_height); height_table = SKIPLIST_HEIGHT_TABLE___NAME$(skiplist); max = height_table[skiplist->max_height - 1]; u64_random_uniform(&j, max); k = j; i = 0; while (i < skiplist->max_height - 1 && k > height_table[i]) i++; height = skiplist->max_height - i; assert(height); return height; } bool skiplist_remove___NAME$ (s_skiplist___NAME$ *skiplist, const _TYPE$ _NAME$) { uw level; s_skiplist_node___NAME$ *pred; s_skiplist_node___NAME$ *next; pred = skiplist_pred___NAME$(skiplist, _NAME$); assert(pred); next = SKIPLIST_NODE_NEXT___NAME$(pred, 0); assert(next); next = SKIPLIST_NODE_NEXT___NAME$(next, 0); if (!next || skiplist->compare(_NAME$, next->_NAME$) != 0) { skiplist_node_delete___NAME$(pred); return false; } for (level = 0; level < next->height; level++) { s_skiplist_node___NAME$ *p = SKIPLIST_NODE_NEXT___NAME$(pred, level); SKIPLIST_NODE_NEXT___NAME$(p, level) = SKIPLIST_NODE_NEXT___NAME$(next, level); } skiplist->length--; skiplist_node_delete___NAME$(pred); skiplist_node_delete___NAME$(next); return true; }