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100 lines
3.2 KiB
100 lines
3.2 KiB
/* Copyright (c) 2016, 2017, Oracle and/or its affiliates. All rights reserved.
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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, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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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, version 2.0, for more details.
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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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#ifndef CMP_VARLEN_KEYS_INCLUDED
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#define CMP_VARLEN_KEYS_INCLUDED
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#include <stdio.h>
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#include <functional>
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#include "my_dbug.h"
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#include "sql/sort_param.h"
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#include "sql/sql_array.h"
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/**
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A compare function for variable-length keys used by filesort().
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For record format documentation, @see Sort_param.
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@param sort_field_array array of field descriptors for sorting
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@param use_hash compare hash values (for grouping of JSON data)
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@param s1 pointer to record 1
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@param s2 pointer to record 2
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@return true/false according to sorting order
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*/
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inline bool cmp_varlen_keys(
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Bounds_checked_array<st_sort_field> sort_field_array, bool use_hash,
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const uchar *s1, const uchar *s2) {
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const uchar *kp1 = s1 + Sort_param::size_of_varlength_field;
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const uchar *kp2 = s2 + Sort_param::size_of_varlength_field;
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int res;
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for (const st_sort_field &sort_field : sort_field_array) {
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uint kp1_len, kp2_len, kp_len;
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if (sort_field.maybe_null) {
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const int k1_nullbyte = *kp1++;
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const int k2_nullbyte = *kp2++;
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if (k1_nullbyte != k2_nullbyte) return k1_nullbyte < k2_nullbyte;
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if (k1_nullbyte == 0 || k1_nullbyte == 0xff) {
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if (!sort_field.is_varlen) {
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kp1 += sort_field.length;
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kp2 += sort_field.length;
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}
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continue; // Both key parts are null, nothing to compare
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}
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}
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if (sort_field.is_varlen) {
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DBUG_ASSERT(uint4korr(kp1) >= 4);
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DBUG_ASSERT(uint4korr(kp2) >= 4);
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kp1_len = uint4korr(kp1) - 4;
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kp1 += 4;
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kp2_len = uint4korr(kp2) - 4;
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kp2 += 4;
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kp_len = std::min(kp1_len, kp2_len);
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} else {
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kp_len = kp1_len = kp2_len = sort_field.length;
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}
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res = memcmp(kp1, kp2, kp_len);
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if (res) return res < 0;
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if (kp1_len != kp2_len) {
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if (sort_field.reverse)
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return kp2_len < kp1_len;
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else
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return kp1_len < kp2_len;
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}
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kp1 += kp1_len;
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kp2 += kp2_len;
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}
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if (use_hash) {
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// Compare hashes at the end of sort keys
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return memcmp(kp1, kp2, 8) < 0;
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} else {
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return false;
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}
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}
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#endif // CMP_VARLEN_KEYS_INCLUDED
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