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/* Copyright (C) 2003 MySQL AB
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; either version 2 of the License, or
(at your option) any later version.
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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#define DBTUX_CMP_CPP
#include "Dbtux.hpp"
/*
* Search key vs node prefix or entry.
*
* The comparison starts at given attribute position. The position is
* updated by number of equal initial attributes found. The entry data
* may be partial in which case CmpUnknown may be returned.
*
* The attributes are normalized and have variable size given in words.
*/
int
Dbtux::cmpSearchKey(const Frag& frag, unsigned& start, ConstData searchKey, ConstData entryData, unsigned maxlen)
{
const unsigned numAttrs = frag.m_numAttrs;
const DescEnt& descEnt = getDescEnt(frag.m_descPage, frag.m_descOff);
// skip to right position in search key only
for (unsigned i = 0; i < start; i++) {
jam();
searchKey += AttributeHeaderSize + searchKey.ah().getDataSize();
}
// number of words of entry data left
unsigned len2 = maxlen;
int ret = 0;
while (start < numAttrs) {
if (len2 <= AttributeHeaderSize) {
jam();
ret = NdbSqlUtil::CmpUnknown;
break;
}
len2 -= AttributeHeaderSize;
if (! searchKey.ah().isNULL()) {
if (! entryData.ah().isNULL()) {
jam();
// verify attribute id
const DescAttr& descAttr = descEnt.m_descAttr[start];
ndbrequire(searchKey.ah().getAttributeId() == descAttr.m_primaryAttrId);
ndbrequire(entryData.ah().getAttributeId() == descAttr.m_primaryAttrId);
// sizes
const unsigned size1 = searchKey.ah().getDataSize();
const unsigned size2 = min(entryData.ah().getDataSize(), len2);
len2 -= size2;
// compare
NdbSqlUtil::Cmp* const cmp = c_sqlCmp[start];
const Uint32* const p1 = &searchKey[AttributeHeaderSize];
const Uint32* const p2 = &entryData[AttributeHeaderSize];
const bool full = (maxlen == MaxAttrDataSize);
ret = (*cmp)(0, p1, size1 << 2, p2, size2 << 2, full);
if (ret != 0) {
jam();
break;
}
} else {
jam();
// not NULL > NULL
ret = +1;
break;
}
} else {
if (! entryData.ah().isNULL()) {
jam();
// NULL < not NULL
ret = -1;
break;
}
}
searchKey += AttributeHeaderSize + searchKey.ah().getDataSize();
entryData += AttributeHeaderSize + entryData.ah().getDataSize();
start++;
}
return ret;
}
/*
* Scan bound vs node prefix or entry.
*
* Compare lower or upper bound and index entry data. The entry data
* may be partial in which case CmpUnknown may be returned. Otherwise
* returns -1 if the bound is to the left of the entry and +1 if the
* bound is to the right of the entry.
*
* The routine is similar to cmpSearchKey, but 0 is never returned.
* Suppose all attributes compare equal. Recall that all bounds except
* possibly the last one are non-strict. Use the given bound direction
* (0-lower 1-upper) and strictness of last bound to return -1 or +1.
*
* Following example illustrates this. We are at (a=2, b=3).
*
* idir bounds strict return
* 0 a >= 2 and b >= 3 no -1
* 0 a >= 2 and b > 3 yes +1
* 1 a <= 2 and b <= 3 no +1
* 1 a <= 2 and b < 3 yes -1
*
* The attributes are normalized and have variable size given in words.
*/
int
Dbtux::cmpScanBound(const Frag& frag, unsigned idir, ConstData boundInfo, unsigned boundCount, ConstData entryData, unsigned maxlen)
{
const DescEnt& descEnt = getDescEnt(frag.m_descPage, frag.m_descOff);
// direction 0-lower 1-upper
ndbrequire(idir <= 1);
// number of words of data left
unsigned len2 = maxlen;
// in case of no bounds, init last type to something non-strict
unsigned type = 4;
while (boundCount != 0) {
if (len2 <= AttributeHeaderSize) {
jam();
return NdbSqlUtil::CmpUnknown;
}
len2 -= AttributeHeaderSize;
// get and skip bound type (it is used after the loop)
type = boundInfo[0];
boundInfo += 1;
if (! boundInfo.ah().isNULL()) {
if (! entryData.ah().isNULL()) {
jam();
// verify attribute id
const Uint32 index = boundInfo.ah().getAttributeId();
ndbrequire(index < frag.m_numAttrs);
const DescAttr& descAttr = descEnt.m_descAttr[index];
ndbrequire(entryData.ah().getAttributeId() == descAttr.m_primaryAttrId);
// sizes
const unsigned size1 = boundInfo.ah().getDataSize();
const unsigned size2 = min(entryData.ah().getDataSize(), len2);
len2 -= size2;
// compare
NdbSqlUtil::Cmp* const cmp = c_sqlCmp[index];
const Uint32* const p1 = &boundInfo[AttributeHeaderSize];
const Uint32* const p2 = &entryData[AttributeHeaderSize];
const bool full = (maxlen == MaxAttrDataSize);
int ret = (*cmp)(0, p1, size1 << 2, p2, size2 << 2, full);
if (ret != 0) {
jam();
return ret;
}
} else {
jam();
// not NULL > NULL
return +1;
}
} else {
jam();
if (! entryData.ah().isNULL()) {
jam();
// NULL < not NULL
return -1;
}
}
boundInfo += AttributeHeaderSize + boundInfo.ah().getDataSize();
entryData += AttributeHeaderSize + entryData.ah().getDataSize();
boundCount -= 1;
}
// all attributes were equal
const int strict = (type & 0x1);
return (idir == 0 ? (strict == 0 ? -1 : +1) : (strict == 0 ? +1 : -1));
}
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