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851
by Brian Aker
Class rewrite of Session (aka get all of the junk out) |
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/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
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*
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* Copyright (C) 2008 Sun Microsystems
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef DRIZZLED_UNIQUE_H
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#define DRIZZLED_UNIQUE_H
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/*
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Unique -- class for unique (removing of duplicates).
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Puts all values to the TREE. If the tree becomes too big,
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it's dumped to the file. User can request sorted values, or
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just iterate through them. In the last case tree merging is performed in
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memory simultaneously with iteration, so it should be ~2-3x faster.
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*/
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class Unique :public Sql_alloc |
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{
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DYNAMIC_ARRAY file_ptrs; |
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ulong max_elements; |
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size_t max_in_memory_size; |
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IO_CACHE file; |
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TREE tree; |
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unsigned char *record_pointers; |
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bool flush(); |
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uint32_t size; |
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public: |
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ulong elements; |
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Unique(qsort_cmp2 comp_func, void *comp_func_fixed_arg, |
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uint32_t size_arg, size_t max_in_memory_size_arg); |
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~Unique(); |
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ulong elements_in_tree() { return tree.elements_in_tree; } |
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inline bool unique_add(void *ptr) |
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{
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if (tree.elements_in_tree > max_elements && flush()) |
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return(1); |
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return(!tree_insert(&tree, ptr, 0, tree.custom_arg)); |
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}
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bool get(Table *table); |
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static double get_use_cost(uint32_t *buffer, uint32_t nkeys, uint32_t key_size, |
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size_t max_in_memory_size); |
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inline static int get_cost_calc_buff_size(ulong nkeys, uint32_t key_size, |
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size_t max_in_memory_size) |
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{
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register size_t max_elems_in_tree= |
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(1 + max_in_memory_size / ALIGN_SIZE(sizeof(TREE_ELEMENT)+key_size)); |
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895
by Brian Aker
Completion (?) of uint conversion. |
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return (int) (sizeof(uint32_t)*(1 + nkeys/max_elems_in_tree)); |
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851
by Brian Aker
Class rewrite of Session (aka get all of the junk out) |
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}
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void reset(); |
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bool walk(tree_walk_action action, void *walk_action_arg); |
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friend int unique_write_to_file(unsigned char* key, element_count count, Unique *unique); |
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friend int unique_write_to_ptrs(unsigned char* key, element_count count, Unique *unique); |
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};
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#endif /* DRIZZLED_UNIQUE_H */ |