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(svn r15216) -Feature: native support for Transport Tycoon (Original) savegames. Based on SVXConverter's source code and documentation by Roman Vetter

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smatz
2009-01-23 02:35:17 +00:00
parent 80e59f375f
commit f0ff90d71c
14 changed files with 898 additions and 266 deletions
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98
src/saveload/oldloader.cpp
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@@ -17,12 +17,13 @@
#include "oldloader.h"
enum {
HEADER_SIZE = 49,
TTO_HEADER_SIZE = 41,
TTD_HEADER_SIZE = 49,
};
uint32 _bump_assert_value;
static inline OldChunkType GetOldChunkType(OldChunkType type) {return (OldChunkType)GB(type, 0, 8);}
static inline OldChunkType GetOldChunkType(OldChunkType type) {return (OldChunkType)GB(type, 0, 4);}
static inline OldChunkType GetOldChunkVarType(OldChunkType type) {return (OldChunkType)(GB(type, 8, 8) << 8);}
static inline OldChunkType GetOldChunkFileType(OldChunkType type) {return (OldChunkType)(GB(type, 16, 8) << 16);}
@@ -101,12 +102,17 @@ byte ReadByte(LoadgameState *ls)
*/
bool LoadChunk(LoadgameState *ls, void *base, const OldChunks *chunks)
{
const OldChunks *chunk = chunks;
byte *base_ptr = (byte*)base;
while (chunk->type != OC_END) {
for (const OldChunks *chunk = chunks; chunk->type != OC_END; chunk++) {
if (((chunk->type & OC_TTD) && (_savegame_type == SGT_TTO)) ||
((chunk->type & OC_TTO) && (_savegame_type != SGT_TTO))) {
/* TTD(P)-only chunk, but TTO savegame || TTO-only chunk, but TTD/TTDP savegame */
continue;
}
byte *ptr = (byte*)chunk->ptr;
if ((chunk->type & OC_DEREFERENCE_POINTER) != 0) ptr = *(byte**)ptr;
if (chunk->type & OC_DEREFERENCE_POINTER) ptr = *(byte**)ptr;
for (uint i = 0; i < chunk->amount; i++) {
if (ls->failed) return false;
@@ -164,8 +170,6 @@ bool LoadChunk(LoadgameState *ls, void *base, const OldChunks *chunks)
if (chunk->amount > 1 && chunk->ptr != NULL) ptr += CalcOldVarLen(chunk->type);
}
}
chunk++;
}
return true;
@@ -194,30 +198,72 @@ static void InitLoading(LoadgameState *ls)
_settings_game.construction.freeform_edges = false; // disable so we can convert map array (SetTileType is still used)
}
/**
* Verifies the title has a valid checksum
* @param title title and checksum
* @return true iff the title is valid
* @note the title (incl. checksum) has to be at least 49 (HEADER_SIZE) bytes long!
* @note the title (incl. checksum) has to be at least 41/49 (HEADER_SIZE) bytes long!
*/
static bool VerifyOldNameChecksum(char *title)
static bool VerifyOldNameChecksum(char *title, uint len)
{
uint16 sum = 0;
for (uint i = 0; i < HEADER_SIZE - 2; i++) {
for (uint i = 0; i < len - 2; i++) {
sum += title[i];
sum = ROL(sum, 1);
}
sum ^= 0xAAAA; // computed checksum
uint16 sum2 = title[HEADER_SIZE - 2]; // checksum in file
SB(sum2, 8, 8, title[HEADER_SIZE - 1]);
uint16 sum2 = title[len - 2]; // checksum in file
SB(sum2, 8, 8, title[len - 1]);
return sum == sum2;
}
static inline bool CheckOldSavegameType(FILE *f, char *temp, const char *last, uint len)
{
assert(last - temp + 1 >= len);
fseek(f, 0, SEEK_SET);
if (fread(temp, 1, len, f) != len) {
temp[0] = '\0'; // if reading failed, make the name empty
return false;
}
bool ret = VerifyOldNameChecksum(temp, len);
temp[len - 2] = '\0'; // name is nul-terminated in savegame, but it's better to be sure
return ret;
}
assert_compile(TTD_HEADER_SIZE >= TTO_HEADER_SIZE);
static SavegameType DetermineOldSavegameType(FILE *f, char *title, const char *last)
{
char temp[TTD_HEADER_SIZE];
SavegameType type = SGT_TTO;
if (!CheckOldSavegameType(f, temp, lastof(temp), TTO_HEADER_SIZE)) {
type = SGT_TTD;
if (!CheckOldSavegameType(f, temp, lastof(temp), TTD_HEADER_SIZE)) {
type = SGT_INVALID;
}
}
if (title != NULL) {
switch (type) {
case SGT_TTO: title = strecpy(title, "(TTO) ", last); break;
case SGT_TTD: title = strecpy(title, "(TTD) ", last); break;
default: title = strecpy(title, "(broken) ", last); break;
}
title = strecpy(title, temp, last);
}
return type;
}
typedef bool LoadOldMainProc(LoadgameState *ls);
bool LoadOldSaveGame(const char *file)
{
LoadgameState ls;
@@ -234,8 +280,19 @@ bool LoadOldSaveGame(const char *file)
return false;
}
char temp[HEADER_SIZE];
if (fread(temp, 1, HEADER_SIZE, ls.file) != HEADER_SIZE || !VerifyOldNameChecksum(temp) || !LoadOldMain(&ls)) {
SavegameType type = DetermineOldSavegameType(ls.file, NULL, NULL);
LoadOldMainProc *proc = NULL;
switch (type) {
case SGT_TTO: proc = &LoadTTOMain; break;
case SGT_TTD: proc = &LoadTTDMain; break;
default: break;
}
_savegame_type = type;
if (proc == NULL || !proc(&ls)) {
SetSaveLoadError(STR_GAME_SAVELOAD_ERROR_DATA_INTEGRITY_CHECK_FAILED);
fclose(ls.file);
return false;
@@ -249,23 +306,16 @@ bool LoadOldSaveGame(const char *file)
void GetOldSaveGameName(const char *path, const char *file, char *title, const char *last)
{
char filename[MAX_PATH];
char temp[HEADER_SIZE];
snprintf(filename, lengthof(filename), "%s" PATHSEP "%s", path, file);
FILE *f = fopen(filename, "rb");
temp[0] = '\0'; // name is nul-terminated in savegame ...
if (f == NULL) {
*title = '\0';
return;
}
bool broken = (fread(temp, 1, HEADER_SIZE, f) != HEADER_SIZE || !VerifyOldNameChecksum(temp));
temp[HEADER_SIZE - 2] = '\0'; // ... but it's better to be sure
if (broken) title = strecpy(title, "(broken) ", last);
title = strecpy(title, temp, last);
DetermineOldSavegameType(f, title, last);
fclose(f);
}