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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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
#include "agi/agi.h"
namespace Agi {
/**
* Decode logic resource
* This function decodes messages from the specified raw logic resource
* into a message list.
* @param logicNr The number of the logic resource to decode.
*/
int AgiEngine::decodeLogic(int16 logicNr) {
AgiLogic &logic = _game.logics[logicNr];
AgiDir &dirLogic = _game.dirLogic[logicNr];
// bytecode section:
// u16 bytecode size
// u8[] bytecode
uint16 bytecodeSize = READ_LE_UINT16(logic.data);
// message section:
// u8 message count
// u16 messages size (2 + offsets + strings)
// u16[] string offsets (relative to message section + 1)
// string[] strings (null terminated, possibly encrypted)
int messageSectionPos = 2 + bytecodeSize;
uint8 messageCount = logic.data[messageSectionPos];
uint16 messagesSize = READ_LE_UINT16(logic.data + messageSectionPos + 1);
int stringOffsetsPos = messageSectionPos + 3;
int stringsPos = stringOffsetsPos + (2 * messageCount);
int stringsSize = messagesSize - 2 - (2 * messageCount);
// decrypt the message strings if the logic was not compressed
// and the logic has messages.
if ((~dirLogic.flags & RES_COMPRESSED) && messageCount > 0) {
decrypt(logic.data + stringsPos, stringsSize);
}
// reset logic pointers
logic.sIP = 2;
logic.cIP = 2;
logic.size = messageSectionPos; // exclude messages from logic size
// allocate list of pointers to message texts. last entry is null.
logic.numTexts = messageCount;
logic.texts = (const char **)calloc(1 + logic.numTexts, sizeof(char *));
if (logic.texts == nullptr) {
free(logic.data);
logic.data = nullptr;
logic.numTexts = 0;
return errNotEnoughMemory;
}
// populate list of pointers to message texts
for (int i = 0; i < messageCount; i++) {
int stringOffset = READ_LE_UINT16(logic.data + stringOffsetsPos + (i * 2));
if (stringOffset != 0) {
// offset is relative to the message section + 1
stringOffset += messageSectionPos + 1;
logic.texts[i] = (const char *)(logic.data + stringOffset);
} else {
// TODO: does this happen? when is a string offset zero?
logic.texts[i] = "";
}
}
// set loaded flag
dirLogic.flags |= RES_LOADED;
return errOK;
}
/**
* Unload logic resource
* This function unloads the specified logic resource, freeing any
* memory chunks allocated for this resource.
* @param logicNr The number of the logic resource to unload
*/
void AgiEngine::unloadLogic(int16 logicNr) {
AgiLogic &logic = _game.logics[logicNr];
AgiDir &dirLogic = _game.dirLogic[logicNr];
if (dirLogic.flags & RES_LOADED) {
free(logic.data);
logic.data = nullptr;
free(logic.texts);
logic.texts = nullptr;
logic.numTexts = 0;
dirLogic.flags &= ~RES_LOADED;
}
logic.sIP = 2;
logic.cIP = 2;
}
} // End of namespace Agi
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