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Diffstat (limited to 'mysql/mysys/tree.c')
| -rw-r--r-- | mysql/mysys/tree.c | 760 |
1 files changed, 760 insertions, 0 deletions
diff --git a/mysql/mysys/tree.c b/mysql/mysys/tree.c new file mode 100644 index 0000000..1f21b67 --- /dev/null +++ b/mysql/mysys/tree.c @@ -0,0 +1,760 @@ +/* Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved. + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ + +/* + Code for handling red-black (balanced) binary trees. + key in tree is allocated accrding to following: + + 1) If size < 0 then tree will not allocate keys and only a pointer to + each key is saved in tree. + compare and search functions uses and returns key-pointer + + 2) If size == 0 then there are two options: + - key_size != 0 to tree_insert: The key will be stored in the tree. + - key_size == 0 to tree_insert: A pointer to the key is stored. + compare and search functions uses and returns key-pointer. + + 3) if key_size is given to init_tree then each node will continue the + key and calls to insert_key may increase length of key. + if key_size > sizeof(pointer) and key_size is a multiple of 8 (double + allign) then key will be put on a 8 alligned adress. Else + the key will be on adress (element+1). This is transparent for user + compare and search functions uses a pointer to given key-argument. + + - If you use a free function for tree-elements and you are freeing + the element itself, you should use key_size = 0 to init_tree and + tree_search + + The actual key in TREE_ELEMENT is saved as a pointer or after the + TREE_ELEMENT struct. + If one uses only pointers in tree one can use tree_set_pointer() to + change address of data. + + Implemented by monty. +*/ + +/* + NOTE: + tree->compare function should be ALWAYS called as + (*tree->compare)(custom_arg, ELEMENT_KEY(tree,element), key) + and not other way around, as + (*tree->compare)(custom_arg, key, ELEMENT_KEY(tree,element)) + + ft_boolean_search.c (at least) relies on that. +*/ + +#include "mysys_priv.h" +#include "my_sys.h" +#include <m_string.h> +#include <my_tree.h> +#include "my_base.h" + +#define BLACK 1 +#define RED 0 +#define DEFAULT_ALLOC_SIZE 8192 +#define DEFAULT_ALIGN_SIZE 8192 + +static void delete_tree_element(TREE *,TREE_ELEMENT *); +static int tree_walk_left_root_right(TREE *,TREE_ELEMENT *, + tree_walk_action,void *); +static int tree_walk_right_root_left(TREE *,TREE_ELEMENT *, + tree_walk_action,void *); +static void left_rotate(TREE_ELEMENT **parent,TREE_ELEMENT *leaf); +static void right_rotate(TREE_ELEMENT **parent, TREE_ELEMENT *leaf); +static void rb_insert(TREE *tree,TREE_ELEMENT ***parent, + TREE_ELEMENT *leaf); +static void rb_delete_fixup(TREE *tree,TREE_ELEMENT ***parent); + + + /* The actuall code for handling binary trees */ + +#ifndef DBUG_OFF +static int test_rb_tree(TREE_ELEMENT *element); +#endif + +void init_tree(TREE *tree, size_t default_alloc_size, ulong memory_limit, + int size, qsort_cmp2 compare, my_bool with_delete, + tree_element_free free_element, const void *custom_arg) +{ + DBUG_ENTER("init_tree"); + DBUG_PRINT("enter",("tree: 0x%lx size: %d", (long) tree, size)); + + if (default_alloc_size < DEFAULT_ALLOC_SIZE) + default_alloc_size= DEFAULT_ALLOC_SIZE; + default_alloc_size= MY_ALIGN(default_alloc_size, DEFAULT_ALIGN_SIZE); + memset(&tree->null_element, 0, sizeof(tree->null_element)); + tree->root= &tree->null_element; + tree->compare=compare; + tree->size_of_element=size > 0 ? (uint) size : 0; + tree->memory_limit=memory_limit; + tree->free=free_element; + tree->allocated=0; + tree->elements_in_tree=0; + tree->custom_arg = custom_arg; + tree->null_element.colour=BLACK; + tree->null_element.left=tree->null_element.right=0; + tree->flag= 0; + if (!free_element && size >= 0 && + ((uint) size <= sizeof(void*) || ((uint) size & (sizeof(void*)-1)))) + { + /* + We know that the data doesn't have to be aligned (like if the key + contains a double), so we can store the data combined with the + TREE_ELEMENT. + */ + tree->offset_to_key=sizeof(TREE_ELEMENT); /* Put key after element */ + /* Fix allocation size so that we don't lose any memory */ + default_alloc_size/=(sizeof(TREE_ELEMENT)+size); + if (!default_alloc_size) + default_alloc_size=1; + default_alloc_size*=(sizeof(TREE_ELEMENT)+size); + } + else + { + tree->offset_to_key=0; /* use key through pointer */ + tree->size_of_element+=sizeof(void*); + } + if (!(tree->with_delete=with_delete)) + { + init_alloc_root(key_memory_TREE, + &tree->mem_root, default_alloc_size, 0); + tree->mem_root.min_malloc=(sizeof(TREE_ELEMENT)+tree->size_of_element); + } + DBUG_VOID_RETURN; +} + +static void free_tree(TREE *tree, myf free_flags) +{ + DBUG_ENTER("free_tree"); + DBUG_PRINT("enter",("tree: 0x%lx", (long) tree)); + + if (tree->root) /* If initialized */ + { + if (tree->with_delete) + delete_tree_element(tree,tree->root); + else + { + if (tree->free) + { + if (tree->memory_limit) + (*tree->free)(NULL, free_init, tree->custom_arg); + delete_tree_element(tree,tree->root); + if (tree->memory_limit) + (*tree->free)(NULL, free_end, tree->custom_arg); + } + free_root(&tree->mem_root, free_flags); + } + } + tree->root= &tree->null_element; + tree->elements_in_tree=0; + tree->allocated=0; + + DBUG_VOID_RETURN; +} + +void delete_tree(TREE* tree) +{ + free_tree(tree, MYF(0)); /* my_free() mem_root if applicable */ +} + +void reset_tree(TREE* tree) +{ + /* do not free mem_root, just mark blocks as free */ + free_tree(tree, MYF(MY_MARK_BLOCKS_FREE)); +} + + +static void delete_tree_element(TREE *tree, TREE_ELEMENT *element) +{ + if (element != &tree->null_element) + { + delete_tree_element(tree,element->left); + if (tree->free) + (*tree->free)(ELEMENT_KEY(tree,element), free_free, tree->custom_arg); + delete_tree_element(tree,element->right); + if (tree->with_delete) + my_free(element); + } +} + + +/* + insert, search and delete of elements + + The following should be true: + parent[0] = & parent[-1][0]->left || + parent[0] = & parent[-1][0]->right +*/ + +TREE_ELEMENT *tree_insert(TREE *tree, void *key, uint key_size, + const void* custom_arg) +{ + int cmp; + TREE_ELEMENT *element,***parent; + + parent= tree->parents; + *parent = &tree->root; element= tree->root; + for (;;) + { + if (element == &tree->null_element || + (cmp = (*tree->compare)(custom_arg, ELEMENT_KEY(tree,element), + key)) == 0) + break; + if (cmp < 0) + { + *++parent= &element->right; element= element->right; + } + else + { + *++parent = &element->left; element= element->left; + } + } + if (element == &tree->null_element) + { + uint alloc_size=sizeof(TREE_ELEMENT)+key_size+tree->size_of_element; + tree->allocated+=alloc_size; + + if (tree->memory_limit && tree->elements_in_tree + && tree->allocated > tree->memory_limit) + { + reset_tree(tree); + return tree_insert(tree, key, key_size, custom_arg); + } + + key_size+=tree->size_of_element; + if (tree->with_delete) + element=(TREE_ELEMENT *) my_malloc(key_memory_TREE, + alloc_size, MYF(MY_WME)); + else + element=(TREE_ELEMENT *) alloc_root(&tree->mem_root,alloc_size); + if (!element) + return(NULL); + **parent=element; + element->left=element->right= &tree->null_element; + if (!tree->offset_to_key) + { + if (key_size == sizeof(void*)) /* no length, save pointer */ + *((void**) (element+1))=key; + else + { + *((void**) (element+1))= (void*) ((void **) (element+1)+1); + memcpy((uchar*) *((void **) (element+1)),key, + (size_t) (key_size-sizeof(void*))); + } + } + else + memcpy((uchar*) element+tree->offset_to_key,key,(size_t) key_size); + element->count=1; + tree->elements_in_tree++; + rb_insert(tree,parent,element); /* rebalance tree */ + } + else + { + if (tree->flag & TREE_NO_DUPS) + return(NULL); + element->count++; + /* Avoid a wrap over of the count. */ + if (! element->count) + element->count--; + } + DBUG_EXECUTE("check_tree", test_rb_tree(tree->root);); + return element; +} + +int tree_delete(TREE *tree, void *key, uint key_size, const void *custom_arg) +{ + int cmp,remove_colour; + TREE_ELEMENT *element,***parent, ***org_parent, *nod; + if (!tree->with_delete) + return 1; /* not allowed */ + + parent= tree->parents; + *parent= &tree->root; element= tree->root; + for (;;) + { + if (element == &tree->null_element) + return 1; /* Was not in tree */ + if ((cmp = (*tree->compare)(custom_arg, ELEMENT_KEY(tree,element), + key)) == 0) + break; + if (cmp < 0) + { + *++parent= &element->right; element= element->right; + } + else + { + *++parent = &element->left; element= element->left; + } + } + if (element->left == &tree->null_element) + { + (**parent)=element->right; + remove_colour= element->colour; + } + else if (element->right == &tree->null_element) + { + (**parent)=element->left; + remove_colour= element->colour; + } + else + { + org_parent= parent; + *++parent= &element->right; nod= element->right; + while (nod->left != &tree->null_element) + { + *++parent= &nod->left; nod= nod->left; + } + (**parent)=nod->right; /* unlink nod from tree */ + remove_colour= nod->colour; + org_parent[0][0]=nod; /* put y in place of element */ + org_parent[1]= &nod->right; + nod->left=element->left; + nod->right=element->right; + nod->colour=element->colour; + } + if (remove_colour == BLACK) + rb_delete_fixup(tree,parent); + if (tree->free) + (*tree->free)(ELEMENT_KEY(tree,element), free_free, tree->custom_arg); + tree->allocated-= sizeof(TREE_ELEMENT) + tree->size_of_element + key_size; + my_free(element); + tree->elements_in_tree--; + return 0; +} + + +void *tree_search(TREE *tree, void *key, const void *custom_arg) +{ + int cmp; + TREE_ELEMENT *element=tree->root; + + for (;;) + { + if (element == &tree->null_element) + return (void*) 0; + if ((cmp = (*tree->compare)(custom_arg, ELEMENT_KEY(tree,element), + key)) == 0) + return ELEMENT_KEY(tree,element); + if (cmp < 0) + element=element->right; + else + element=element->left; + } +} + +void *tree_search_key(TREE *tree, const void *key, + TREE_ELEMENT **parents, TREE_ELEMENT ***last_pos, + enum ha_rkey_function flag, const void *custom_arg) +{ + int cmp; + TREE_ELEMENT *element= tree->root; + TREE_ELEMENT **last_left_step_parent= NULL, **last_right_step_parent= NULL; + TREE_ELEMENT **last_equal_element= NULL; + +/* + TODO: support for HA_READ_KEY_OR_PREV, HA_READ_PREFIX flags if needed. +*/ + + *parents = &tree->null_element; + while (element != &tree->null_element) + { + *++parents= element; + if ((cmp= (*tree->compare)(custom_arg, ELEMENT_KEY(tree, element), + key)) == 0) + { + switch (flag) { + case HA_READ_KEY_EXACT: + case HA_READ_KEY_OR_NEXT: + case HA_READ_BEFORE_KEY: + last_equal_element= parents; + cmp= 1; + break; + case HA_READ_AFTER_KEY: + cmp= -1; + break; + case HA_READ_PREFIX_LAST: + case HA_READ_PREFIX_LAST_OR_PREV: + last_equal_element= parents; + cmp= -1; + break; + default: + return NULL; + } + } + if (cmp < 0) /* element < key */ + { + last_right_step_parent= parents; + element= element->right; + } + else + { + last_left_step_parent= parents; + element= element->left; + } + } + switch (flag) { + case HA_READ_KEY_EXACT: + case HA_READ_PREFIX_LAST: + *last_pos= last_equal_element; + break; + case HA_READ_KEY_OR_NEXT: + *last_pos= last_equal_element ? last_equal_element : last_left_step_parent; + break; + case HA_READ_AFTER_KEY: + *last_pos= last_left_step_parent; + break; + case HA_READ_PREFIX_LAST_OR_PREV: + *last_pos= last_equal_element ? last_equal_element : last_right_step_parent; + break; + case HA_READ_BEFORE_KEY: + *last_pos= last_right_step_parent; + break; + default: + return NULL; + } + return *last_pos ? ELEMENT_KEY(tree, **last_pos) : NULL; +} + +/* + Search first (the most left) or last (the most right) tree element +*/ +void *tree_search_edge(TREE *tree, TREE_ELEMENT **parents, + TREE_ELEMENT ***last_pos, int child_offs) +{ + TREE_ELEMENT *element= tree->root; + + *parents= &tree->null_element; + while (element != &tree->null_element) + { + *++parents= element; + element= ELEMENT_CHILD(element, child_offs); + } + *last_pos= parents; + return **last_pos != &tree->null_element ? + ELEMENT_KEY(tree, **last_pos) : NULL; +} + +void *tree_search_next(TREE *tree, TREE_ELEMENT ***last_pos, int l_offs, + int r_offs) +{ + TREE_ELEMENT *x= **last_pos; + + if (ELEMENT_CHILD(x, r_offs) != &tree->null_element) + { + x= ELEMENT_CHILD(x, r_offs); + *++*last_pos= x; + while (ELEMENT_CHILD(x, l_offs) != &tree->null_element) + { + x= ELEMENT_CHILD(x, l_offs); + *++*last_pos= x; + } + return ELEMENT_KEY(tree, x); + } + else + { + TREE_ELEMENT *y= *--*last_pos; + while (y != &tree->null_element && x == ELEMENT_CHILD(y, r_offs)) + { + x= y; + y= *--*last_pos; + } + return y == &tree->null_element ? NULL : ELEMENT_KEY(tree, y); + } +} + +/* + Expected that tree is fully balanced + (each path from root to leaf has the same length) +*/ +ha_rows tree_record_pos(TREE *tree, const void *key, + enum ha_rkey_function flag, const void *custom_arg) +{ + int cmp; + TREE_ELEMENT *element= tree->root; + double left= 1; + double right= tree->elements_in_tree; + + while (element != &tree->null_element) + { + if ((cmp= (*tree->compare)(custom_arg, ELEMENT_KEY(tree, element), + key)) == 0) + { + switch (flag) { + case HA_READ_KEY_EXACT: + case HA_READ_BEFORE_KEY: + cmp= 1; + break; + case HA_READ_AFTER_KEY: + cmp= -1; + break; + default: + return HA_POS_ERROR; + } + } + if (cmp < 0) /* element < key */ + { + element= element->right; + left= (left + right) / 2; + } + else + { + element= element->left; + right= (left + right) / 2; + } + } + switch (flag) { + case HA_READ_KEY_EXACT: + case HA_READ_BEFORE_KEY: + return (ha_rows) right; + case HA_READ_AFTER_KEY: + return (ha_rows) left; + default: + return HA_POS_ERROR; + } +} + +int tree_walk(TREE *tree, tree_walk_action action, void *argument, TREE_WALK visit) +{ + switch (visit) { + case left_root_right: + return tree_walk_left_root_right(tree,tree->root,action,argument); + case right_root_left: + return tree_walk_right_root_left(tree,tree->root,action,argument); + } + return 0; /* Keep gcc happy */ +} + +static int tree_walk_left_root_right(TREE *tree, TREE_ELEMENT *element, tree_walk_action action, void *argument) +{ + int error; + if (element->left) /* Not null_element */ + { + if ((error=tree_walk_left_root_right(tree,element->left,action, + argument)) == 0 && + (error=(*action)(ELEMENT_KEY(tree,element), + (element_count) element->count, + argument)) == 0) + error=tree_walk_left_root_right(tree,element->right,action,argument); + return error; + } + return 0; +} + +static int tree_walk_right_root_left(TREE *tree, TREE_ELEMENT *element, tree_walk_action action, void *argument) +{ + int error; + if (element->right) /* Not null_element */ + { + if ((error=tree_walk_right_root_left(tree,element->right,action, + argument)) == 0 && + (error=(*action)(ELEMENT_KEY(tree,element), + (element_count) element->count, + argument)) == 0) + error=tree_walk_right_root_left(tree,element->left,action,argument); + return error; + } + return 0; +} + + + /* Functions to fix up the tree after insert and delete */ + +static void left_rotate(TREE_ELEMENT **parent, TREE_ELEMENT *leaf) +{ + TREE_ELEMENT *y; + + y=leaf->right; + leaf->right=y->left; + parent[0]=y; + y->left=leaf; +} + +static void right_rotate(TREE_ELEMENT **parent, TREE_ELEMENT *leaf) +{ + TREE_ELEMENT *x; + + x=leaf->left; + leaf->left=x->right; + parent[0]=x; + x->right=leaf; +} + +static void rb_insert(TREE *tree, TREE_ELEMENT ***parent, TREE_ELEMENT *leaf) +{ + TREE_ELEMENT *y,*par,*par2; + + leaf->colour=RED; + while (leaf != tree->root && (par=parent[-1][0])->colour == RED) + { + if (par == (par2=parent[-2][0])->left) + { + y= par2->right; + if (y->colour == RED) + { + par->colour=BLACK; + y->colour=BLACK; + leaf=par2; + parent-=2; + leaf->colour=RED; /* And the loop continues */ + } + else + { + if (leaf == par->right) + { + left_rotate(parent[-1],par); + par=leaf; /* leaf is now parent to old leaf */ + } + par->colour=BLACK; + par2->colour=RED; + right_rotate(parent[-2],par2); + break; + } + } + else + { + y= par2->left; + if (y->colour == RED) + { + par->colour=BLACK; + y->colour=BLACK; + leaf=par2; + parent-=2; + leaf->colour=RED; /* And the loop continues */ + } + else + { + if (leaf == par->left) + { + right_rotate(parent[-1],par); + par=leaf; + } + par->colour=BLACK; + par2->colour=RED; + left_rotate(parent[-2],par2); + break; + } + } + } + tree->root->colour=BLACK; +} + +static void rb_delete_fixup(TREE *tree, TREE_ELEMENT ***parent) +{ + TREE_ELEMENT *x,*w,*par; + + x= **parent; + while (x != tree->root && x->colour == BLACK) + { + if (x == (par=parent[-1][0])->left) + { + w=par->right; + if (w->colour == RED) + { + w->colour=BLACK; + par->colour=RED; + left_rotate(parent[-1],par); + parent[0]= &w->left; + *++parent= &par->left; + w=par->right; + } + if (w->left->colour == BLACK && w->right->colour == BLACK) + { + w->colour=RED; + x=par; + parent--; + } + else + { + if (w->right->colour == BLACK) + { + w->left->colour=BLACK; + w->colour=RED; + right_rotate(&par->right,w); + w=par->right; + } + w->colour=par->colour; + par->colour=BLACK; + w->right->colour=BLACK; + left_rotate(parent[-1],par); + x=tree->root; + break; + } + } + else + { + w=par->left; + if (w->colour == RED) + { + w->colour=BLACK; + par->colour=RED; + right_rotate(parent[-1],par); + parent[0]= &w->right; + *++parent= &par->right; + w=par->left; + } + if (w->right->colour == BLACK && w->left->colour == BLACK) + { + w->colour=RED; + x=par; + parent--; + } + else + { + if (w->left->colour == BLACK) + { + w->right->colour=BLACK; + w->colour=RED; + left_rotate(&par->left,w); + w=par->left; + } + w->colour=par->colour; + par->colour=BLACK; + w->left->colour=BLACK; + right_rotate(parent[-1],par); + x=tree->root; + break; + } + } + } + x->colour=BLACK; +} + +#ifndef DBUG_OFF + + /* Test that the proporties for a red-black tree holds */ + +static int test_rb_tree(TREE_ELEMENT *element) +{ + int count_l,count_r; + + if (!element->left) + return 0; /* Found end of tree */ + if (element->colour == RED && + (element->left->colour == RED || element->right->colour == RED)) + { + printf("Wrong tree: Found two red in a row\n"); + return -1; + } + count_l=test_rb_tree(element->left); + count_r=test_rb_tree(element->right); + if (count_l >= 0 && count_r >= 0) + { + if (count_l == count_r) + return count_l+(element->colour == BLACK); + printf("Wrong tree: Incorrect black-count: %d - %d\n",count_l,count_r); + } + return -1; +} +#endif |