Blueprint for 010 editor that allows you to partly read the OVL files of Planet Coaster

ovltemplate.bt

//------------------------------------------------
//--- 010 Editor v7.0 Binary Template
//
//      File: Overlay
//   Authors: Joeywp
//   Version: 0.08
//   Purpose: Structing the Overlay files for Planet Coaster (Cobra Engine)
//  Category: 
// File Mask: *.ovl
//  ID Bytes: 
//   History: 
//------------------------------------------------

typedef struct {
    uint Block1; // Always 0
    uint Block2; // Always 0
    uint Block3; // Always 0
    ushort Block4a;
    ushort Block4b; // Always 0
    ushort Block5a;
    ushort Block5b;
    ushort Block6a; // Always 0
    ushort Block6b; // Always 0
    ushort Block7a;
    ushort Block7b;
    ushort Block8a;
    ushort Block8b;
    ushort Block9a;
    ushort Block9b; // Always 0
    ushort Block10a; // Always 0
    ushort Block10b; // Always 0
    uint Unknown1; // Some kind of size?
    uint CompressedDataSize;
    uint DecompressedDataSize;
} BLOCKCOUNT;

typedef struct {
    char extraData [3072];
} EXTRADATA <bgcolor=cLtGray>;

typedef struct {
    uint StringPointer <comment=StringPointer>;
    uint Djb2Hash;
    ubyte Unknown1; // Loader type?
    ubyte Unknown2;
    ubyte Unknown3;
    ubyte Unknown4;
} LOADERSYMBOL <bgcolor=cLtRed>;

typedef struct {
    uint NameStringPointer <comment=StringPointer>;
    uint Unknown1;
    uint Hash;
    uint LoaderType;
    uint StringOffset;
    ubyte SymbolsToResolve;
    ubyte ExtraDataCount;
    ubyte Unknown3;
    ubyte Unknown4;
    //LOADERSYMBOL symbols [symbolCount];
} LOADER <bgcolor=0xFFFF00>;

typedef struct {
    uint magicNumber;
    ubyte VersionOrGame; // Seen 0x0 (0) at Elite Dangerous, 0x2 (2) at Disneyland Kinect, 0x8 (8) at Planet Coaster
    ubyte Unknown1a; // Seen 0x12 (18)
    ubyte BigEndian; // Seen 1 if file uses big-endian, else it uses little-endian
    ubyte Unknown1c; // Seen 1

    ubyte Unknown2a; // Seen 148
    ubyte Unknown2b; // 32
    ubyte Unknown2c; // Seen 0
    ubyte Unknown2d; // Seen 0

    uint Unknown3; // Seen 0
    uint StringTableSize;
    uint Unknown4; // Seen 0
    uint Unknown5; // Seen 0, 1, 9, bitflag? Also seen 3 at ED
    ushort Unknown6a; // Seen 0. Seen more at ED
    ushort LoaderCount; // Seen 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 29. Also seen 10 at ED
    uint FileCount1; // Seen values between 0 and 47968, mostly less then 1000
    uint FileCount2; // Same as Unknown7
    uint Unknown9; // Seen values between 0 and 57331, rarely more then 1000
    uint Unknown10; // Seen the values 1 to 3, also 4 and 5 at ED
    uint Unknown11; // Seen the values 0 to 6, also 7 and 8 at ED
    uint Unknown12; // Seen numbers between 0 and 2885, mostly less then or equal to 151
    uint Unknown13; // Seen numbers between 0 and 2362, mostly less then or equal to 231
    uint Unknown14; // Seen numbers between 0 and 2739
    uint Unknown15; // Seen values between 0 and 38
    ushort Unknown16a; // Seen 0
    ushort Unknown16b; // Seen 0
    ushort Unknown17a; // Seen 0
    ushort Unknown17b; // Seen 0
    uint Unknown18; // Seen 0
    uint StaticTextLength;
    uint FileCount3; // Seen numbers between 0 and 47968
    uint Unknown21; // Seen numbers between 0 and 1103, mostly lower then 300
    uint Unknown22; // Seen 0
    uint Unknown23; // Seen 0
    uint Unknown24; // Seen 0
    uint Unknown25; // Seen 0
    uint Unknown26; // Seen 0
    uint Unknown27; // Seen 0
    uint Unknown28; // Seen 0
    uint Unknown29; // Seen 0
    uint Unknown30; // Seen 0
    uint Unknown31; // Seen 0
    uint Unknown32; // Seen 0
    uint Unknown33; // Seen 0
    uint Unknown34; // Seen 0
} HEADER <bgcolor=cLtBlue>;


LittleEndian();
HEADER header;

if (header.BigEndian == 1) {
    return;
}

local int64 stringTablePosition = FTell();
byte stringtable [header.StringTableSize] <bgcolor=0x00FF00>;
if (header.LoaderCount > 0) {
    local int i;
    local int j;
    local int s;
    LOADER loaders [header.LoaderCount] <comment=LoaderComment>;

    for (i = 0; i < header.LoaderCount; i++) {
        for (s = 0; s < loaders[i].ExtraDataCount; s++) {
            EXTRADATA data;
        }
        for (j = 0; j < loaders[i].SymbolsToResolve; j++) {
            LOADERSYMBOL loaderSymbol <comment=SymbolComment>;
        }
    }
}

char STATIC [header.StaticTextLength] <bgcolor=cLtGray>;
BLOCKCOUNT blockCount <bgcolor=cLtGray>;

// Skip for now as I don't know how to correctly handle the space inbetween
FSeek(FileSize() - blockCount.CompressedDataSize);
char compressedData [blockCount.CompressedDataSize] <bgcolor=0x0000FF>;

//char uncompressedData [blockCount.UncompressedPartSize];
//char compressedData [blockCount.CompressedPartSize] <bgcolor=cLtGray>;

string StringPointer(uint pointer) {
    //local string value = "";
    local uint i;
    local uint count = 0;

    for (i = pointer; i < header.StringTableSize; i++) {
        if (stringtable[i] == 0) {
            break;
        }
        count ++;
    }
    char value[count+1];
    for (i = 0; i < count; i++) {
        value[i] = stringtable[pointer + i];
    }

    return value;
}
string SymbolComment(LOADERSYMBOL &symbol) {
    return StringPointer(symbol.StringPointer);
}
string LoaderComment(LOADER &symbol) {
    return StringPointer(symbol.NameStringPointer);
}