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/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
/*
* This code is based on original Soltys source code
* Copyright (c) 1994-1995 Janus B. Wisniewski and L.K. Avalon
*/
#include "cge/btfile.h"
#include "common/system.h"
#include "common/str.h"
#include "cge/cge.h"
#include "common/debug.h"
#include "common/debug-channels.h"
namespace CGE {
BtFile::BtFile(const char *name, IOMode mode, Crypt *crpt)
: IoHand(name, mode, crpt) {
debugC(1, kCGEDebugFile, "BtFile::BtFile(%s, %d, crpt)", name, mode);
for (int i = 0; i < kBtLevel; i++) {
_buff[i]._page = new BtPage;
_buff[i]._pgNo = kBtValNone;
_buff[i]._indx = -1;
_buff[i]._updt = false;
assert(_buff[i]._page != NULL);
}
}
BtFile::~BtFile() {
debugC(1, kCGEDebugFile, "BtFile::~BtFile()");
for (int i = 0; i < kBtLevel; i++) {
putPage(i, false);
delete _buff[i]._page;
}
}
void BtFile::putPage(int lev, bool hard) {
debugC(1, kCGEDebugFile, "BtFile::putPage(%d, %s)", lev, hard ? "true" : "false");
if (hard || _buff[lev]._updt) {
seek(_buff[lev]._pgNo * sizeof(BtPage));
write((uint8 *) _buff[lev]._page, sizeof(BtPage));
_buff[lev]._updt = false;
}
}
BtPage *BtFile::getPage(int lev, uint16 pgn) {
debugC(1, kCGEDebugFile, "BtFile::getPage(%d, %d)", lev, pgn);
if (_buff[lev]._pgNo != pgn) {
int32 pos = pgn * sizeof(BtPage);
putPage(lev, false);
_buff[lev]._pgNo = pgn;
if (size() > pos) {
seek((uint32) pgn * sizeof(BtPage));
read((uint8 *) _buff[lev]._page, sizeof(BtPage));
_buff[lev]._updt = false;
} else {
_buff[lev]._page->_hea._count = 0;
_buff[lev]._page->_hea._down = kBtValNone;
memset(_buff[lev]._page->_data, '\0', sizeof(_buff[lev]._page->_data));
_buff[lev]._updt = true;
}
_buff[lev]._indx = -1;
}
return _buff[lev]._page;
}
BtKeypack *BtFile::find(const char *key) {
debugC(1, kCGEDebugFile, "BtFile::find(%s)", key);
int lev = 0;
uint16 nxt = kBtValRoot;
while (!_error) {
BtPage *pg = getPage(lev, nxt);
// search
if (pg->_hea._down != kBtValNone) {
int i;
for (i = 0; i < pg->_hea._count; i++) {
// Does this work, or does it have to compare the entire buffer?
if (scumm_strnicmp((const char *)key, (const char*)pg->_inn[i]._key, kBtKeySize) < 0)
break;
}
nxt = (i) ? pg->_inn[i - 1]._down : pg->_hea._down;
_buff[lev]._indx = i - 1;
lev++;
} else {
int i;
for (i = 0; i < pg->_hea._count - 1; i++) {
if (scumm_stricmp((const char *)key, (const char *)pg->_lea[i]._key) <= 0)
break;
}
_buff[lev]._indx = i;
return &pg->_lea[i];
}
}
return NULL;
}
int keycomp(const void *k1, const void *k2) {
return scumm_strnicmp((const char *) k1, (const char*) k2, kBtKeySize);
}
void BtFile::make(BtKeypack *keypack, uint16 count) {
debugC(1, kCGEDebugFile, "BtFile::make(keypack, %d)", count);
#if kBtLevel != 2
#error This tiny BTREE implementation works with exactly 2 levels!
#endif
_fqsort(keypack, count, sizeof(*keypack), keycomp);
uint16 n = 0;
BtPage *Root = getPage(0, n++);
BtPage *Leaf = getPage(1, n);
Root->_hea._down = n;
putPage(0, true);
while (count--) {
if (Leaf->_hea._count >= ArrayCount(Leaf->_lea)) {
putPage(1, true); // save filled page
Leaf = getPage(1, ++n); // take empty page
memcpy(Root->_inn[Root->_hea._count]._key, keypack->_key, kBtKeySize);
Root->_inn[Root->_hea._count++]._down = n;
_buff[0]._updt = true;
}
Leaf->_lea[Leaf->_hea._count++] = *(keypack++);
_buff[1]._updt = true;
}
}
} // End of namespace CGE
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