9c9292949f
Many of the member variables that are used in the oldloader are inside types that are not standard layout types. Using pointer arithmetics to determine addresses of members inside types that are not standard layout is generally undefined behaviour. If we'd use C++17, it is conditionally supported, which means each compiler may or may not support it. And even then using it for individual array elements is syntactically not supported the the standard offsetof function.
137 lines
4.6 KiB
C++
137 lines
4.6 KiB
C++
/*
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* This file is part of OpenTTD.
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* OpenTTD 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, version 2.
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* OpenTTD 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.
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* See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
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*/
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/** @file oldloader.h Declarations of strctures and function used in loader of old savegames */
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#ifndef OLDLOADER_H
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#define OLDLOADER_H
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#include "saveload.h"
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#include "../tile_type.h"
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static const uint BUFFER_SIZE = 4096;
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static const uint OLD_MAP_SIZE = 256 * 256;
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struct LoadgameState {
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FILE *file;
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uint chunk_size;
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bool decoding;
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byte decode_char;
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uint buffer_count;
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uint buffer_cur;
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byte buffer[BUFFER_SIZE];
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uint total_read;
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};
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/* OldChunk-Type */
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enum OldChunkType {
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OC_SIMPLE = 0,
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OC_NULL = 1,
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OC_CHUNK = 2,
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OC_ASSERT = 3,
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/* 4 bits allocated (16 max) */
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OC_TTD = 1 << 4, ///< chunk is valid ONLY for TTD savegames
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OC_TTO = 1 << 5, ///< -//- TTO (default is neither of these)
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/* 4 bits allocated */
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OC_VAR_I8 = 1 << 8,
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OC_VAR_U8 = 2 << 8,
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OC_VAR_I16 = 3 << 8,
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OC_VAR_U16 = 4 << 8,
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OC_VAR_I32 = 5 << 8,
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OC_VAR_U32 = 6 << 8,
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OC_VAR_I64 = 7 << 8,
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OC_VAR_U64 = 8 << 8,
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/* 8 bits allocated (256 max) */
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OC_FILE_I8 = 1 << 16,
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OC_FILE_U8 = 2 << 16,
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OC_FILE_I16 = 3 << 16,
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OC_FILE_U16 = 4 << 16,
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OC_FILE_I32 = 5 << 16,
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OC_FILE_U32 = 6 << 16,
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/* 8 bits allocated (256 max) */
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OC_INT8 = OC_VAR_I8 | OC_FILE_I8,
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OC_UINT8 = OC_VAR_U8 | OC_FILE_U8,
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OC_INT16 = OC_VAR_I16 | OC_FILE_I16,
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OC_UINT16 = OC_VAR_U16 | OC_FILE_U16,
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OC_INT32 = OC_VAR_I32 | OC_FILE_I32,
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OC_UINT32 = OC_VAR_U32 | OC_FILE_U32,
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OC_TILE = OC_VAR_U32 | OC_FILE_U16,
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/**
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* Dereference the pointer once before writing to it,
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* so we do not have to use big static arrays.
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*/
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OC_DEREFERENCE_POINTER = 1 << 31,
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OC_END = 0, ///< End of the whole chunk, all 32 bits set to zero
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};
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DECLARE_ENUM_AS_BIT_SET(OldChunkType)
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typedef bool OldChunkProc(LoadgameState *ls, int num);
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typedef void *OffsetProc(void *base);
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struct OldChunks {
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OldChunkType type; ///< Type of field
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uint32 amount; ///< Amount of fields
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void *ptr; ///< Pointer where to save the data (takes precedence over #offset)
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OffsetProc *offset; ///< Pointer to function that returns the actual memory address of a member (ignored if #ptr is not nullptr)
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OldChunkProc *proc; ///< Pointer to function that is called with OC_CHUNK
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};
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/* If it fails, check lines above.. */
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static_assert(sizeof(TileIndex) == 4);
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extern uint _bump_assert_value;
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byte ReadByte(LoadgameState *ls);
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bool LoadChunk(LoadgameState *ls, void *base, const OldChunks *chunks);
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bool LoadTTDMain(LoadgameState *ls);
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bool LoadTTOMain(LoadgameState *ls);
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static inline uint16 ReadUint16(LoadgameState *ls)
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{
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byte x = ReadByte(ls);
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return x | ReadByte(ls) << 8;
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}
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static inline uint32 ReadUint32(LoadgameState *ls)
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{
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uint16 x = ReadUint16(ls);
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return x | ReadUint16(ls) << 16;
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}
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/* Help:
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* - OCL_SVAR: load 'type' to offset 'offset' in a struct of type 'base', which must also
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* be given via base in LoadChunk() as real pointer
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* - OCL_VAR: load 'type' to a global var
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* - OCL_END: every struct must end with this
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* - OCL_NULL: read 'amount' of bytes and send them to /dev/null or something
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* - OCL_CHUNK: load another proc to load a part of the savegame, 'amount' times
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* - OCL_ASSERT: to check if we are really at the place we expect to be.. because old savegames are too binary to be sure ;)
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*/
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#define OCL_SVAR(type, base, offset) { type, 1, nullptr, [] (void *b) -> void * { return std::addressof(static_cast<base *>(b)->offset); }, nullptr }
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#define OCL_VAR(type, amount, pointer) { type, amount, pointer, nullptr, nullptr }
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#define OCL_END() { OC_END, 0, nullptr, nullptr, nullptr }
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#define OCL_CNULL(type, amount) { OC_NULL | type, amount, nullptr, nullptr, nullptr }
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#define OCL_CCHUNK(type, amount, proc) { OC_CHUNK | type, amount, nullptr, nullptr, proc }
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#define OCL_ASSERT(type, size) { OC_ASSERT | type, 1, (void *)(size_t)size, nullptr, nullptr }
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#define OCL_NULL(amount) OCL_CNULL((OldChunkType)0, amount)
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#define OCL_CHUNK(amount, proc) OCL_CCHUNK((OldChunkType)0, amount, proc)
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#endif /* OLDLOADER_H */
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