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444 lines
15 KiB
444 lines
15 KiB
/* Copyright (c) 2011, 2019, 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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Without limiting anything contained in the foregoing, this file,
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which is part of C Driver for MySQL (Connector/C), is also subject to the
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Universal FOSS Exception, version 1.0, a copy of which can be found at
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http://oss.oracle.com/licenses/universal-foss-exception.
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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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/**
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@file mysys/my_compare.cc
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*/
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#include <sys/types.h>
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#include <algorithm>
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#include "m_ctype.h"
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#include "my_base.h"
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#include "my_byteorder.h"
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#include "my_compare.h"
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#include "my_inttypes.h"
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#include "my_macros.h"
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#include "myisampack.h"
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#define CMP_NUM(a, b) (((a) < (b)) ? -1 : ((a) == (b)) ? 0 : 1)
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int ha_compare_text(const CHARSET_INFO *charset_info, const uchar *a,
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uint a_length, const uchar *b, uint b_length,
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bool part_key) {
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if (!part_key)
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return charset_info->coll->strnncollsp(charset_info, a, a_length, b,
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b_length);
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return charset_info->coll->strnncoll(charset_info, a, a_length, b, b_length,
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part_key);
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}
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static int compare_bin(const uchar *a, uint a_length, const uchar *b,
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uint b_length, bool part_key, bool skip_end_space) {
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uint length = MY_MIN(a_length, b_length);
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const uchar *end = a + length;
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int flag;
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while (a < end)
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if ((flag = (int)*a++ - (int)*b++)) return flag;
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if (part_key && b_length < a_length) return 0;
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if (skip_end_space && a_length != b_length) {
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int swap = 1;
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/*
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We are using space compression. We have to check if longer key
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has next character < ' ', in which case it's less than the shorter
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key that has an implicite space afterwards.
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This code is identical to the one in
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strings/ctype-simple.c:my_strnncollsp_simple
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*/
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if (a_length < b_length) {
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/* put shorter key in a */
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a_length = b_length;
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a = b;
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swap = -1; /* swap sign of result */
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}
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for (end = a + a_length - length; a < end; a++) {
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if (*a != ' ') return (*a < ' ') ? -swap : swap;
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}
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return 0;
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}
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return (int)(a_length - b_length);
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}
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/*
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Compare two keys
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SYNOPSIS
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ha_key_cmp()
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keyseg Array of key segments of key to compare
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a First key to compare, in format from _mi_pack_key()
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This is normally key specified by user
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b Second key to compare. This is always from a row
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key_length Length of key to compare. This can be shorter than
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a to just compare sub keys
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next_flag How keys should be compared
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If bit SEARCH_FIND is not set the keys includes the row
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position and this should also be compared
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diff_pos OUT Number of first keypart where values differ, counting
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from one.
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diff_pos[1] OUT (b + diff_pos[1]) points to first value in tuple b
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that is different from corresponding value in tuple a.
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EXAMPLES
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Example1: if the function is called for tuples
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('aaa','bbb') and ('eee','fff'), then
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diff_pos[0] = 1 (as 'aaa' != 'eee')
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diff_pos[1] = 0 (offset from beggining of tuple b to 'eee' keypart).
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Example2: if the index function is called for tuples
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('aaa','bbb') and ('aaa','fff'),
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diff_pos[0] = 2 (as 'aaa' != 'eee')
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diff_pos[1] = 3 (offset from beggining of tuple b to 'fff' keypart,
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here we assume that first key part is CHAR(3) NOT NULL)
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NOTES
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Number-keys can't be splited
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RETURN VALUES
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<0 If a < b
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0 If a == b
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>0 If a > b
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*/
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#define FCMP(A, B) ((int)(A) - (int)(B))
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int ha_key_cmp(const HA_KEYSEG *keyseg, const uchar *a, const uchar *b,
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uint key_length, uint nextflag, uint *diff_pos) {
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int flag;
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int16 s_1, s_2;
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int32 l_1, l_2;
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uint32 u_1, u_2;
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float f_1, f_2;
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double d_1, d_2;
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uint next_key_length;
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const uchar *orig_b = b;
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*diff_pos = 0;
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for (; (int)key_length > 0; key_length = next_key_length, keyseg++) {
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const uchar *end;
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uint piks = !(keyseg->flag & HA_NO_SORT);
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(*diff_pos)++;
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diff_pos[1] = (uint)(b - orig_b);
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/* Handle NULL part */
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if (keyseg->null_bit) {
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key_length--;
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if (*a != *b && piks) {
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flag = (int)*a - (int)*b;
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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}
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b++;
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if (!*a++) /* If key was NULL */
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{
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if (nextflag == (SEARCH_FIND | SEARCH_UPDATE))
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nextflag = SEARCH_SAME; /* Allow duplicate keys */
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else if (nextflag & SEARCH_NULL_ARE_NOT_EQUAL) {
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/*
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This is only used from mi_check() to calculate cardinality.
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It can't be used when searching for a key as this would cause
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compare of (a,b) and (b,a) to return the same value.
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*/
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return -1;
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}
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next_key_length = key_length;
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continue; /* To next key part */
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}
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}
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end = a + MY_MIN(keyseg->length, key_length);
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next_key_length = key_length - keyseg->length;
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switch ((enum ha_base_keytype)keyseg->type) {
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case HA_KEYTYPE_TEXT: /* Ascii; Key is converted */
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if (keyseg->flag & HA_SPACE_PACK) {
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uint pack_length;
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int a_length = get_key_length(&a);
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int b_length = get_key_pack_length(&b, &pack_length);
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next_key_length = key_length - b_length - pack_length;
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if (piks &&
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(flag = ha_compare_text(
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keyseg->charset, a, a_length, b, b_length,
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(bool)((nextflag & SEARCH_PREFIX) && next_key_length <= 0))))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a += a_length;
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b += b_length;
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break;
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} else {
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uint length = (uint)(end - a), a_length = length, b_length = length;
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if (piks &&
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(flag = ha_compare_text(
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keyseg->charset, a, a_length, b, b_length,
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(bool)((nextflag & SEARCH_PREFIX) && next_key_length <= 0))))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b += length;
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}
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break;
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case HA_KEYTYPE_BINARY:
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case HA_KEYTYPE_BIT:
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if (keyseg->flag & HA_SPACE_PACK) {
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uint pack_length;
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int a_length = get_key_length(&a);
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int b_length = get_key_pack_length(&b, &pack_length);
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next_key_length = key_length - b_length - pack_length;
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if (piks && (flag = compare_bin(a, a_length, b, b_length,
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(bool)((nextflag & SEARCH_PREFIX) &&
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next_key_length <= 0),
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1)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a += a_length;
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b += b_length;
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break;
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} else {
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uint length = keyseg->length;
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if (piks && (flag = compare_bin(a, length, b, length,
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(bool)((nextflag & SEARCH_PREFIX) &&
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next_key_length <= 0),
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0)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a += length;
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b += length;
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}
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break;
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case HA_KEYTYPE_VARTEXT1:
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case HA_KEYTYPE_VARTEXT2: {
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uint pack_length;
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int a_length = get_key_length(&a);
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int b_length = get_key_pack_length(&b, &pack_length);
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next_key_length = key_length - b_length - pack_length;
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if (piks &&
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(flag = ha_compare_text(
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keyseg->charset, a, a_length, b, b_length,
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(bool)((nextflag & SEARCH_PREFIX) && next_key_length <= 0))))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a += a_length;
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b += b_length;
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break;
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}
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case HA_KEYTYPE_VARBINARY1:
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case HA_KEYTYPE_VARBINARY2: {
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uint pack_length;
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int a_length = get_key_length(&a);
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int b_length = get_key_pack_length(&b, &pack_length);
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next_key_length = key_length - b_length - pack_length;
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if (piks && (flag = compare_bin(a, a_length, b, b_length,
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(bool)((nextflag & SEARCH_PREFIX) &&
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next_key_length <= 0),
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0)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a += a_length;
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b += b_length;
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} break;
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case HA_KEYTYPE_INT8: {
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int i_1 = static_cast<signed char>(*a);
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int i_2 = static_cast<signed char>(*b);
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if (piks && (flag = CMP_NUM(i_1, i_2)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b++;
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break;
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}
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case HA_KEYTYPE_SHORT_INT:
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s_1 = mi_sint2korr(a);
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s_2 = mi_sint2korr(b);
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if (piks && (flag = CMP_NUM(s_1, s_2)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b += 2; /* sizeof(short int); */
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break;
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case HA_KEYTYPE_USHORT_INT: {
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uint16 us_1, us_2;
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us_1 = mi_sint2korr(a);
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us_2 = mi_sint2korr(b);
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if (piks && (flag = CMP_NUM(us_1, us_2)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b += 2; /* sizeof(short int); */
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break;
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}
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case HA_KEYTYPE_LONG_INT:
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l_1 = mi_sint4korr(a);
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l_2 = mi_sint4korr(b);
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if (piks && (flag = CMP_NUM(l_1, l_2)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b += 4; /* sizeof(long int); */
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break;
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case HA_KEYTYPE_ULONG_INT:
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u_1 = mi_sint4korr(a);
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u_2 = mi_sint4korr(b);
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if (piks && (flag = CMP_NUM(u_1, u_2)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b += 4; /* sizeof(long int); */
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break;
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case HA_KEYTYPE_INT24:
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l_1 = mi_sint3korr(a);
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l_2 = mi_sint3korr(b);
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if (piks && (flag = CMP_NUM(l_1, l_2)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b += 3;
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break;
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case HA_KEYTYPE_UINT24:
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l_1 = mi_uint3korr(a);
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l_2 = mi_uint3korr(b);
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if (piks && (flag = CMP_NUM(l_1, l_2)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b += 3;
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break;
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case HA_KEYTYPE_FLOAT:
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f_1 = mi_float4get(a);
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f_2 = mi_float4get(b);
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/*
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The following may give a compiler warning about floating point
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comparison not being safe, but this is ok in this context as
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we are bascily doing sorting
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*/
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if (piks && (flag = CMP_NUM(f_1, f_2)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b += 4; /* sizeof(float); */
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break;
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case HA_KEYTYPE_DOUBLE:
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d_1 = mi_float8get(a);
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d_2 = mi_float8get(b);
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/*
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The following may give a compiler warning about floating point
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comparison not being safe, but this is ok in this context as
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we are bascily doing sorting
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*/
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if (piks && (flag = CMP_NUM(d_1, d_2)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b += 8; /* sizeof(double); */
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break;
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case HA_KEYTYPE_NUM: /* Numeric key */
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{
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int swap_flag = 0;
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int alength, blength;
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if (keyseg->flag & HA_REVERSE_SORT) {
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std::swap(a, b);
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swap_flag = 1; /* Remember swap of a & b */
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end = a + (int)(end - b);
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}
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if (keyseg->flag & HA_SPACE_PACK) {
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alength = *a++;
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blength = *b++;
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end = a + alength;
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next_key_length = key_length - blength - 1;
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} else {
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alength = (int)(end - a);
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blength = keyseg->length;
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/* remove pre space from keys */
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for (; alength && *a == ' '; a++, alength--)
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;
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for (; blength && *b == ' '; b++, blength--)
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;
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}
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if (piks) {
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if (*a == '-') {
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if (*b != '-') return -1;
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a++;
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b++;
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std::swap(a, b);
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std::swap(alength, blength);
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swap_flag = 1 - swap_flag;
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alength--;
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blength--;
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end = a + alength;
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} else if (*b == '-')
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return 1;
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while (alength && (*a == '+' || *a == '0')) {
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a++;
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alength--;
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}
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while (blength && (*b == '+' || *b == '0')) {
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b++;
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blength--;
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}
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if (alength != blength) return (alength < blength) ? -1 : 1;
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while (a < end)
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if (*a++ != *b++) return ((int)a[-1] - (int)b[-1]);
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} else {
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b += (end - a);
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a = end;
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}
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if (swap_flag) /* Restore pointers */
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std::swap(a, b);
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break;
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}
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case HA_KEYTYPE_LONGLONG: {
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longlong ll_a, ll_b;
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ll_a = mi_sint8korr(a);
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ll_b = mi_sint8korr(b);
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if (piks && (flag = CMP_NUM(ll_a, ll_b)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b += 8;
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break;
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}
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case HA_KEYTYPE_ULONGLONG: {
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ulonglong ll_a, ll_b;
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ll_a = mi_uint8korr(a);
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ll_b = mi_uint8korr(b);
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if (piks && (flag = CMP_NUM(ll_a, ll_b)))
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return ((keyseg->flag & HA_REVERSE_SORT) ? -flag : flag);
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a = end;
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b += 8;
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break;
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}
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case HA_KEYTYPE_END: /* Ready */
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goto end; /* diff_pos is incremented */
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}
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}
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(*diff_pos)++;
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end:
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if (!(nextflag & SEARCH_FIND)) {
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uint i;
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if (nextflag & (SEARCH_NO_FIND | SEARCH_LAST)) /* Find record after key */
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return (nextflag & (SEARCH_BIGGER | SEARCH_LAST)) ? -1 : 1;
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flag = 0;
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for (i = keyseg->length; i-- > 0;) {
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if (*a++ != *b++) {
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flag = FCMP(a[-1], b[-1]);
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break;
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}
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}
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if (nextflag & SEARCH_SAME) return (flag); /* read same */
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if (nextflag & SEARCH_BIGGER) return (flag <= 0 ? -1 : 1); /* read next */
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return (flag < 0 ? -1 : 1); /* read previous */
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}
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return 0;
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} /* ha_key_cmp */
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