DAT file format

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1. Preamble

This file was written thanks to the hard work on reverse engineering made
by several people, see the credits section. In case you find any mistake
in the text please report it. A copy of this document should be available
in our official site at http://www.princed.org.


2. Introduction

There are two versions of the DAT file format: DAT v1.0 used in POP 1.x
and DAT v2.0 used in POP 2. In this document we will specify DAT v1.0.
DAT files were made to store levels, images, palettes, wave, midi and
internal speaker sounds. Each type has its own format as described below
in the following sections.
As the format is very old and the original game was distributed in disks,
it is normal to think that the file format uses some kind of checksum
validation to detect file corruptions.
DAT files are indexed, this means that there is an index and you can
access each resource through an ID that is unique for the resource inside
the file.
Images store their height and width but not their palette, so the palette
is another resource and must be shared by a group of images.
PLV files use the extension defined to support a format with only one
level inside.


3. Primitives

This section shows how the PR dat handling primitives works, this library
is useful to access resources without having to worry about the format.
Here you can find the primitive chart of the dat.h library.

3.1. DAT reading and writing primitives

Opening a dat file for RW mode
Syntax:
int mRWBeginDatFile(
 const char* vFile, /* the name of the file to be open */
 unsigned short int *numberOfItems, /* saves the total items count */
 int optionflag /* see optionflag appendix */
);
Return values are:
int mRWCloseDatFile(dontSave);

3.2. DAT reading primitives

int  mReadBeginDatFile(unsigned short int *numberOfItems,
     const char* vFile);
int  mReadFileInDatFile(int indexNumber,unsigned char** data,
     unsigned long int *size);
int  mReadInitResource(tResource** res,const unsigned char* data,
     long size);
void mReadCloseDatFile();

3.3. DAT writing primitives

int  mWriteBeginDatFile(const char* vFile, int optionflag);
void mWriteFileInDatFile(const unsigned char* data, int size);
void mWriteFileInDatFileIgnoreChecksum(unsigned char* data,int size);
void mWriteInitResource(tResource** res);
void mWriteCloseDatFile(tResource* r[],int dontSave,int optionflag, const
     char* backupExtension);


4. DAT v1.0 Format Specifications

4.1. General file specs, index and checksums

All DAT files have an index, this index has a number of items count and
a list of items.
The index is stored at the very end of the file.
The first 6 bytes are reserved to locate the index and know the file size.
Let's define the numbers as:
 US - Unsigned Short: Little endian, 16 bits, storing two groups of 8 bits
      ordered from the less representative to the most representative
      without sign.
      i.e. 65534 is FFFE in hex and is stored FE FF (1111 1110  1111 1111)
      Range: 0 to 65535
      2 bytes
 UL - Unsigned long: Little endian, 32 bits, storing four groups of 8 bits
      each ordered from the less representative to the most representative
      without sign.
      i.e. 65538 is 00010002 in hex and is stored 02 00 01 00
      (0000 0010  0000 0000  0000 0001  0000 0000)
      Range: 0 to 2^32-1
      4 bytes
 SC - Signed char: 8 bits, the first bit is for the sign and the 7 last
      for the number. If the first bit is a 0, then the number is
      positive, if not the number is negative, in that case invert all
      bits and add 1 to get the positive number.
      i.e. -1 is FF (1111 1111), 1 is 01 (0000 0001)
      Range: -128 to 127
      1 byte
 UC - Unsigned char: 8 bits that represent the number.
      i.e. 32 is 20 (0010 0000)
      Range: 0 to 255
      1 byte
Note: Sizes are allways in bytes unless another unit is specified.
Index structures:
The DAT header: Size = 6 bytes
 - Offset 0, size 4, type UL: IndexOffset
          (the location where the index begins)
 - Offset 4, size 2, type US: IndexSize
          (the number of bytes the index has)
          Note that IndexSize is 8*numberOfItems+2
          Note that IndexOffset+IndexSize=file size
The DAT index: Size = IndexSize bytes
 - Offset IndexOffset,   size 2, type US: NumberOfItems
          (resources count)
 - Offset IndexOffset+2, size NumberOfItems*8: The index
          (a list of NumberOfItems blocks of 8-bytes-length index record)
The 8-bytes-length index record (one per item): Size = 8 bytes
 - Relative offset 0, size 2, type US: Item ID
 - Relative offset 2, size 4, type UL: Resource start
          (absolute offset in file)
 - Relative offset 6, size 2, type US: Size of the item
          (not including the checksum byte)
Note:
 POP1 doesn't validate a DAT file checking:
 IndexOffset+IndexSize=FileSize
 this means you can append data at the end of the file.
 PR validates that IndexOffset+IndexSize<=FileSize.
It also compares IndexSize with 8*numberOfItems+2 to determine if a file
 is a valid POP1 DAT file.
Checksum byte:
There is a checksum byte for each item (resource), this is the first byte
of the item, the rest of the bytes are the item data. The item type is not
stored and may only be determined by reading the data and applying some
filters, unfortunately this method may fail. When you extract an item you
should know what kind of item you are extracting.
If you add (sum) the whole item data including checksum and take the less
representative byte (modulus 256) you will get the sum of the file. This
sum must be FF in hex (255 in UC or -1 in SC). If the sum is not FF, then
adjust the checksum in order to set this value to the sum. The best way
to do that is adding all the bytes in the item data (excluding the
checksum) and inverting all the bits. The resulting byte will be the
right checksum.
From now on the specification are special for each data type (that means
we won't include the checksum byte anymore).

4.2. Images

Images are stored compressed and have a header and a compressed data area.
Each image only one header with 6 bytes in it as follows

4.2.1 Headers

The 6-bytes-image header: 6 bytes
 Relative offset 0, size 2, type US: Height
 Relative offset 2, size 2, type UL: Width
 Relative offset 4, size 2: Information
Information is a set of bits where:
 the first 8 are zeros
 the next 4 are the resolution:
  if it is 1011 (B in hex) then the image has 16 colours
  if it is 0000 (0 in hex) then the image has 2 colours
  so to calculate the bits per pixel there are in the image, just take the
  last 2 bits and add 1. e. g. 11 is 4 (2^4=16 colours) and
 00 is 1 (2^1=2 colours).
 the last 4 bits are the 5 compression types:
  from 0 to 4:
  0 RAW_LR (0000)
  1 RLE_LR (0001)
  2 RLE_UD (0010)
  3 LZG_LR (0011)
  4 LZG_UD (0100)
The following data in the resource is the image compressed with the
algorithm specified by those 4 bits.

4.2.2 Algorithms

RAW_LR means that the data wasn't compressed, it is used for small images.
       The format is saved from left to right (LR) serialising a line to
       the next integer byte if necessary. In case the image was 16
       colours, two pixels per byte (4bpp) will be used. In case the image
       was 2 colours, 8 pixels per byte (1bpp) will be used.
RLE_LR has a Run length encoding (RLE) algorithm, after uncompressed the
       image can be read as a RAW_LR.
RLE_UD is the same as RLE_LR except that after uncompressed the bytes in
    the image must be drawn from up to down and then from left to right.
LZG_LR has some kind of variant of the LZ77 algorithm (the sliding windows
       algorithm), here we named it LZG in honour of Lance Groody, the
       original coder.
       After uncompressed it may be handled as RAW_LR.
LZG_UD Uses LZG compression but is drawn from top to bottom as RLE_UD

4.2.2.1 Run length encoding (RLE)

The first byte is allways a control byte, the format is SC. If the control
byte is negative, then the next byte must be repeated n times as the bit
inverted control byte says, after the next byte (the one that was
repeated)
another control byte is stored.
If the control byte is positive or zero just copy textual the next n bytes
where n is the control byte plus one. After that, the next byte is the
following control byte.
If you reach a control byte but the image size is passed, then you have
completed the image.

4.2.2.2 LZ variant (LZG) =

This is a simplified algorithm explanation:
Definition: "print" means to commit a byte into the current location
            of the output stream.
The output stream is a slide window initialised with zeros.
The first byte of the input stream is a maskbyte.
For each of the 8 bits in the maskbyte the next actions must be performed:
 If the bit is 1 print the next unread byte to the slide window
 If the bit is a zero read the next two bytes as control bytes with the
 following format (RRRRRRSS SSSSSSSS):
  - 6  bits for the copy size number (R). Add 3 to this number.
       Range: 2 to 66
  - 10 bits for the slide position (S). Add 66 to this number.
       Range: 66 to 1090
  Then print in the slide window the next R bytes that are the same slide
  window starting with the S'th byte.
After all the maskbyte is read and processed, the following input byte is
another maskbyte. Use the same procedure to finish uncompressing the file.
This version of the algorithm is limited to 1024 bytes due to the slide
window size. In case you want to know the full algorithm and see how it
works for bigger images you should use the source, Luke.
This is the full uncompression function source. Note that this is part of
PR that is under the GPL license. The variables ??�?R??�? and ??�?S??�? are ??�?rep??�? and
??�?loc??�? respectively. The array output is the output stream and oCursor is
the current location. The input array and iCursor variable had the same
meaning for the input stream. The algorithm ends when the full input has
been processed. The maskbyte must remain with 0 for the unexistent bytes,
so if you find the maskbyte not null, it is possible that the input array
wasn't a LZG compressed stream. In that case that non-zero value is going
to be returned. This is the only internal way to detect an error in the
compression layer. All the data that has the latest maskbyte without this
issue will be detected as valid and unpacked normally.
                  Algorithm 4.1: LZG
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)Ecalot
 
 /* A big number (the output must be less that that) */
 #define LZG_MAX_MEMSIZE    32001
 
 /* modulus to be used in the 10 bits of the algorithm */
 #define LZG_WINDOW_SIZE    0x400 /* =1024=1<<10 */
 
 /* LZG expansion algorithm sub function */
 unsigned char popBit(unsigned char *byte) {
   register unsigned char bit=(*byte)&1;
   (*byte)>>=1;
   return bit;
 }
 
 /* Expands LZ Groody algorithm. This is the core of PR.
  * returns 0 on success, non-zero on possible data corruption
  */
 int expandLzg(const unsigned char* input, int inputSize, 
               unsigned char* output, int *outputSize) {
 
   int           loc, oCursor=0, iCursor=0;
   unsigned char maskbyte=0, rep, k;
 
   /* clean output garbage */
   for(loc=LZG_MAX_MEMSIZE;loc--;output[loc]=0);
 
   /* main loop */
   while (iCursor<inputSize) {
     maskbyte=input[iCursor++];
     for (k=8;k&&(iCursor<inputSize);k--) {
       if (popBit(&maskbyte)) {
         output[oCursor++]=input[iCursor++]; /* copy input to output */
       } else {
         /*
          * loc:
          *  10 bits for the slide iCursorition (S). Add 66 to this number.
          * rep:
          *  6 bits for the repetition number (R). Add 3 to this number.
          */
         loc= 66 + ((input[iCursor] & 0x03 /*00000011*/) <<8) + input[iCursor+1];
         rep= 3  + ((input[iCursor] & 0xfc /*11111100*/) >>2);
         
         iCursor+=2;
         
         while (rep--) { /* repeat pattern in output */
           loc=loc%LZG_WINDOW_SIZE; /* loc is in range 0-1023 */
 
           /*
            * delta is ((loc-oCursor)%LZG_WINDOW_SIZE)
            * this is the offset where the bytes will be looked for
            * in the simple algorithm it is allways negative
            * in bigger images it can be iCursoritive
            * 
            * this value is inside the range -1023 to 1023.
            * if loc>oCursor the result is iCursoritive
            * if loc<oCursor the result is negative
            */
           
           output[oCursor]=output[oCursor+((loc-oCursor)%LZG_WINDOW_SIZE)];
 
           oCursor++;
           loc++;
         }
       }
     }
   }
   
   *outputSize=oCursor;
   return maskbyte;
 }
 

4.3. Palettes

Palettes have 100 bytes allways, after 4 bytes from the beginning the
first 16 records of 3 bytes are the VGA colours stored in the RGB-18 bits
format (6 bits for each colour). Each colour is a number from 0 to 63.
Remember to shift the colour bytes by two to get the colour number from 0
to 256.

4.4. Levels

This table has a summary of the blocks to be used in this section,
you can referr it from the text below.
                  Table 4.1: Level blocks
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)Ecalot
 Length Offset  Block Name
 12:30, 11 Aug 2005 (UTC)~ 12:30, 11 Aug 2005 (UTC)~  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)
 720    0       wall
 720    720     background
 256    1440    door I
 256    1696    door II
 96     1952    links
 64     2048    unknown I
 3      2112    start_position
 3      2115    unknown II
 1      2116    unknown III
 24     2119    guard_location
 24     2143    guard_direction
 24     2167    unknown VI (a)
 24     2191    unknown VI (b)
 24     2215    guard_skill
 24     2239    unknown VI (c)
 24     2263    guard_colour
 16     2287    unknown VI (d)
 2      2303    0F 09 (2319)
All levels has a size of 2305, except in the original game, that the
potion level has a size of 2304 (may be it was wrong trimmed).

4.4.1 Unknown blocks

Blocks described in this section are: Unknown from I to IV.
Unknown III and VI blocks doesn't affect the level if changed, if you find
out what they are used to we will welcome your specification text.
Unknown I may corrupt the level if edited.
We believe unknown II has something to do with the start position, but we
don't know about it.
As unknown II were all zeros for each level in the original set, it was a
team decision to use those bytes for format extension. If one of them is
not the default 00 00 00 hex then the level was extended by the team.
Those extensions are only supported by RoomShaker at this  moment. To see
how those extensions were defined read the appendix I'll write some day.
For the moment you may contact us if you need to know that.

4.4.2 Room mapping

This section explains how the main walls and objects are stored. The
blocks involved here are "wall" and "background"
In a level you can store a maximum of 24 screens (also called rooms) of 30
tiles each, having three stages of 10 tiles each. Screens are numbered
from 1 to 24 (not 0 to 23) because the 0 was reserved special cases.
The wall and background blocks have 24 sub-blocks inside. Those sub-blocks
has a size of 30 bytes each and has a screen associated. So, for example,
the sub-block staring in 0 corresponds to the screen 1 and the sub-block
starting in 690 corresponds to the screen 24.
It is reserved 1 byte from the wall block and one from the background
block for each tile. To locate the appropriate tile you have to do the
following calculation: tile=(screen-1)*30+tileOffset where tileOffset is a
number
from 0 to 29 that means a tile from 0 to 9 if in the upper stage, from
10 to 19 if in the middle stage and 20 to 29 if in the bottom stage.
We define this as the location format and will be used also in the start
position.
Allways looking from the left to the right.
So there is a wall and background byte for each tile in the level and this
is stored this way.
The wall part of the tile stores the main tile form according to the table
below. Note that those are just a limited number of tiles, each code has a
tile in the game. The tiles listed are all the ones needed to make a level
so the missing tiles have an equivalent in this list.
Each tile has a code id, as some codes are repeated this is how you have
to calculate the codes. A tile in the wall part has 8 bits in this format
rrmccccc, where rr are random bits and can be ignored. m is a modifier of
the tile. For example modified loose floors do not fall down. The rest
ccccc is the code of the tile tabled below. Tile names are the same as the
ones used by RoomShaker to keep compatibility.
                  Table 4.2: Foreground Walls
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~~
 Hex  Binary Group  Description
 Ecalot 12:30, 11 Aug 2005 (UTC) 12:30, 11 Aug 2005 (UTC)~ 12:30, 11 Aug 2005 (UTC)  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~
 0x00 00000  free   Empty
 0x01 00001  free   Floor
 0x02 00010  spike  Spikes
 0x03 00011  none   Pillar
 0x04 00100  gate   Gate
 0x05 00101  none   Stuck Button
 0x06 00110  event  Drop Button
 0x07 00111  tapest Tapestry
 0x08 01000  none   Top Big-pillar
 0x09 01001  none   Bottom Big-pillar
 0x0A 01010  potion Potion
 0x0B 01011  none   Loose Floor
 0x0C 01100  ttop   Tapestry Top
 0x0D 01101  none   Mirror
 0x0E 01110  none   Debris
 0x0F 01111  event  Raise Button
 0x10 10000  none   Exit Left
 0x11 10001  none   Exit Right
 0x12 10010  chomp  Chopper
 0x13 10011  none   Torch
 0x14 10100  wall   Wall
 0x15 10101  none   Skeleton
 0x16 10110  none   Sword
 0x17 10111  none   Balcony Left
 0x18 11000  none   Balcony Right
 0x19 11001  none   Lattice Pillar
 0x1A 11010  none   Lattice Support
 0x1B 11011  none   Small Lattice
 0x1C 11100  none   Lattice Left
 0x1D 11101  none   Lattice Right
 0x1E 11110  none   Torch with Debris
 0x1F 11111  none   Null
The background part of the tile stores a modifier or attribute of the
wall part of the tile. This works independently of the modifier bit in the
code. The tile  modifier depends on the group the tile belongs which are
wall, chomp, event, ttop, potion, tapp, gate, spike and free.
The group event allows the 256 modifiers and will be described in 4.4.6.
Note + means allowed for the dungeon environment, - means allowed for the
palace environment.
                  Table 4.3: Background modifiers by group
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)
 Group  Code Description
 12:30, 11 Aug 2005 (UTC)  Ecalot 12:30, 11 Aug 2005 (UTC) 12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~
 none   0x00 This value is used allways for this group
 free   0x00 +Nothing -Blue line
 free   0x01 +Spot1   -No blue line
 free   0x02 +Spot2   -Diamond
 free   0x03 Window
 free   0xFF +Spot3   -Blue line?
 spike  0x00 Normal (allows animation)
 spike  0x01 Barely Out
 spike  0x02 Half Out
 spike  0x03 Fully Out
 spike  0x04 Fully Out
 spike  0x05 Out?
 spike  0x06 Out?
 spike  0x07 Half Out?
 spike  0x08 Barely Out?
 spike  0x09 Disabled
 gate   0x00 Closed
 gate   0x01 Open
 tapest 0x00 -With Lattice
 tapest 0x01 -Alternative Design
 tapest 0x02 -Normal
 tapest 0x03 -Black
 potion 0x00 Empty
 potion 0x01 Health point
 potion 0x02 Life
 potion 0x03 Feather Fall
 potion 0x04 Invert
 potion 0x05 Poison
 potion 0x06 Open
 ttop   0x00 -With lattice
 ttop   0x01 -Alernative design
 ttop   0x02 -Normal
 ttop   0x03 -Black
 ttop   0x04 -Black
 ttop   0x05 -With alternative design and bottom
 ttop   0x06 -With bottom
 ttop   0x07 -With window
 chomp  0x00 Normal
 chomp  0x01 Half Open
 chomp  0x02 Closed
 chomp  0x03 Partially Open
 chomp  0x04 Extra Open
 chomp  0x05 Stuck Open
 wall   0x00 +Normal  -Blue line
 wall   0x01 +Normal  -No Blue line
Note: Some modifiers have not been tested, there may be any other unknown
      tile type we didn't discover.


4.4.2.1 Wall drawing algorithm
This section doesn't have a direct relation with the format because it
describes how the walls must be drawn on the screen. However, as this
information should be usefull to recreate a cloned screen read from the
format we decided to include this section to the document.
Wall drawing depends on what is in the right panel. If the right panel
is not a wall (binary code ends in 10100) a base wall will be drawn and
other random seed will be used. If the right panel is a wall then the main
base wall will be drawn and the described seed will be used.
When the base wall is drawn, the modifiers should be blitted over it.
There are 53 different types of walls using the same base image.
We will call the seed array to the one having the modifier information of
those 53 panels. This array has indexes from 1 to 53 included.
To calculate what value take from the array this calculation must be
performed: panelInfo=seedArray[screenNumber+wallPosition]
where panelInfo is the result modifier information that will be applied to
the base image; seedArray is this array that will be described above as a
table; screenNumber is the number of the screen the wall is (from 1 to 24)
and wallPosition is the position the wall is (from 0 to 29), using the
location format specified in section 4.4.2. This means the first value is
1 (screenNumber=1 and wallPosition=0) and the last is 53 (screenNumber=24
and wallPosition=29).
Modifiers affects the corners of a stone. There are three stone rows per
wall. If the modifier is activated this corner will appear different
(seems to be darker). Another modifier is the gray stone.
                  Table 4.4: Stone modifiers on seed position
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)Ecalot
 Modifier       Seed Positions
 12:30, 11 Aug 2005 (UTC)Ecalot       Ecalot 12:30, 11 Aug 2005 (UTC) 12:30, 11 Aug 2005 (UTC)Ecalot 12:30, 11 Aug 2005 (UTC)
    (First row modifiers)
 Gray stone     2, 5, 14, 17, 26, 32, 35, 50
 Left, bottom   2, 11, 36, 45
 Left, top      37
 Right, bottom  27, 33
 Right, up      4, 10, 31, 37
    (second row)
 Gray stone     none 
 Left, bottom   34, 47
 Left, top      9, 10
 Right, bottom  2, 8, 25, 35
 Right, top     6, 12, 23, 29, 39
    (third row)
 Gray stone     none 
 Left, bottom   none
 Left, top      16
 Right, bottom  none
 Right, top     none
Another modifiers are saved in the seed too. Those modifiers are not
boolean values, they are offsets and sizes. As each stone has a different
size the stone separation offset is saved in the seed.
For the first row, the stones are all the same size and the seed is not
needed.
For the second row we've got the first 20 values, ordered from 1 to 20. 
position        1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20
offsets:        5,4,3,3,1,5,4,2,1, 1, 5, 3, 2, 1, 5, 4, 3, 2, 5, 4
separator size: 0,1,1,0,0,0,1,1,0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0
We'll be adding the next values as soon as we count the pixels ;)
This information can be found in walls.conf file from FreePrince.

4.4.3 Room linking

This section describes the links block.
Each screen is linked to another by each of the four sides. Each link
is stored. There is no screen mapping, just screen linking.
The links block has 24 sub-blocks of 4 bytes each. All those sub-blocks
has its own correspondence with a screen (the block starting at 0 is
related to the screen 1 and the block starting at with 92 is related to
screen 24).
Each block of 4 bytes stores the links this screen links to reserving one
byte per each side in the order left (0), right (1), up (2), down (3).
The number 0 is used when there is no screen there.
Cross links should be made to allow the kid passing from a screen to
another and then coming back to the same screen but it's not a must.

4.4.4 Guard handling

This section specifies the blocks: guard_location, guard_direction,
guard_skill and guard_colour.
Each guard section has 24 bytes, each byte of them corresponds to a screen
so byte 0 is related to screen 1 and byte 13 is related to screen 24.
This screen is where the guard is located. The format only allows one
guard per screen. Each block describes a part of the guard.
The guard_location part of a guard describes where in the screen the guard
is located, this is a number from 0 to 29 if the guard is in the screen or
30 if there is no guard in this screen. Other values are allowed but are
equivalent to 30. The number from 0 to 29 is in the location format
specified in section 4.4.2
The guard_direction part describes where the guard looks at. If the value
is 0, then the guard looks to the right, if the value is the hex FF (-1 or
255) then he looks left. This is the direction format, and will be used in
the start position too.
The guard_skill is how the guard fights, style and lives. Note that the
lives also depends on the level you are. Allowed numbers are from 0 to 9.
TODO: add a skill table
The guard_colour is the palette the guard has (see 4.8).
The default colours are in this table:
                  Table 4.4: Default Guard colours
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~
 Code Pants     Cape
 Ecalot 12:30, 11 Aug 2005 (UTC) 12:30, 11 Aug 2005 (UTC)     Ecalot 12:30, 11 Aug 2005 (UTC)
 0x00 Light     Blue Pink
 0x01 Red       Purple
 0x02 Orange    Yellow
 0x03 Green     Yellow
 0x04 Dark Blue Beige
 0x05 Purple    Beige
 0x06 Yellow    Orange
Other codes may generate random colours because the game is reading
the palette from trashed memory. This may also cause a game crash.
It should (never tested) be possible to add new colours in the guard
palette resource (see 4.8) avoiding the crash due to this reason.


4.4.5 Starting Position

This section describes the start_position block.
This block stores where and how the kid starts in the level. Note that all
level doors that are on the starting screen will be closed in the moment
the level starts.
This block has 3 bytes.
The first byte is the screen, allowed values are from 1 to 24.
The second byte is the location, see the section 4.4.2 for the location
format specifications.
The third byte is the direction, see 4.4.4 for the direction format
specifications.

4.4.6 Door events

This section explains how the doors are handled and specifies the blocks
door I and II.
First of all he have to define what an event line is in this file. An
event line is a link to a door that will be activated. If the event was
triggered with the action close, then the event will close the door, if
the action was open then the event will open the door. An event line has
also a flag to trigger the next event line or not.
An event is defined as a list of event lines, from the first to the last.
The last must have the trigger-next-event-line flag off. This is like a
list of doors that performs an action.
An event performs the action that it was called to do: open those doors or
close them. This action is defined by the type of tile pressed.
Each event line has an ID from 0 to 255. An event has the ID of the first
event line in it.
In section 4.4.2 it is explained how a door trigger is associated to an
event ID. Those are the tiles that starts the event depending on what are
them: closers or openers.
How events are stored:
Each door block has 256 bytes, one per event line. Each event line is
located in an offset that is the event line ID, so event line 30 is
located in the byte 30 of each block.
There is a door I part of an event line and a door II part of it. We'll
define them as byte I and byte II.
You can find there: the door screen, the door location, and the
trigger-next flag. The format is the following:
Let's define:
 Screen as S and it is a number from 1 to 24 (5 bits)
  S = s1 s2 s3 s4 s5
   where sn is the bit n of the binary representation of S
 Location as L and is a number from 0 to 29 (5 bits)
  L = l1 l2 l3 l4 l5
   where ln is the bit n of the binary representation of L
  This number is according to the location format specifications.
 Trigger-next as T and is a 1 for "on" or a 0 for "off" (1 bit)
  T = t1
Byte I  has the form: t1 s4 s5 l1 l2 l3 l4 l5
Byte II has the form: s1 s2 s3  0  0  0  0  0

4.5. Digital Waves

Read them as raw digital wave sound using the following specifications:
                  Table 4.4: Wave Specifications
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)
 Size of Format: 16
 Format:         PCM
 Attributes:     8 bit, mono, unsigned
 Channels:       1
 Sample rate:    11025
 Bytes/Second:   11025
 Block Align:    1
GNU/Linux users can play the raw waves just dropping them inside /dev/dsp
As dat headers are very small it is valid to type in a shell console with
dsp write access: cat digisnd?.dat>/dev/dsp to play the whole wave files.

4.6. Midi music

Standard midi files

4.7. Internal PC Speaker

We are not so sure about it, but we think it is:
 2 unique bytes for headers
 3 bytes per note (2 for frequency and 1 for duration)

4.8. Binary files

Some binary files contains relevant information
The resource number 10 in prince.dat has the VGA guard palettes in it
saving n records of a 16-colour-palette of 3 bytes in the specified
palette format.


5. DAT v2.0 Format Specifications

5.1. General file specs, index and checksums

POP2 DAT files aren't much different from their predecessors from POP1.
The format is similar in almost each way. The main difference is in the
index. As DAT v1.0 used an index in the high data, the DAT v2.0 indexes
are two level encapsulated inside a high data. So there is an index of
indexes.
We will use the same conventions than in the prior chapter.
The checksum validations are still the same.
High data structures:
The DAT header: Size = 6 bytes
 - Offset 0, size 4, type UL: HighDataOffset
          (the location where the highData begins)
 - Offset 4, size 2, type US: HighDataSize
          (the number of bytes the highData has)
          Note that HighDataOffset+HighDataSize=file size
This is similar to DAT v1.0 format, except that the index area is now
called high data.
The high data part of the file contains multiple encapsulated indexes.
Each of those index is indexed in a high data index of indexes. We will
call this index the ??�?master index??�? and the sub index the ??�?slave indexes??�?.
Slave indexes are the real file contents index.

5.2. The master index

The master index is made with:
 - Offset HighDataOffset,   size 2, type US: NumberOfSlaveIndexes
          (the number of the high data sections)
 - Offset HighDataOffset+2, size NumberOfSlaveIndexes*6: The master index record
          (a list of NumberOfSlaveIndexes blocks of 6-bytes-length index
          record each corresponding to one slave index)
The 6-bytes-length index record (one per item): Size = 6 bytes
 - Relative offset 0, size 4, type sting: 4 ASCII bytes string denoting
          the section ID. The character order is inverted.
 - Relative offset 4, size 2, type US: SlaveIndexOffset
          (slave index offset relative to HighDataOffset)
From the end of the DAT High Data index to the end of the file there is
the High Data section contents (where the HighDataOffset relative offsets
points to).
There are different 4 bytes ASCII strings section IDs. When the string is
less than 4 bytes, they are ended in hex 0x00 is used. We will denote it with
the cardinal # symbol. The character order is inverted, so for example the
text SLAP becomes PALS, MARF becomes FRAM, #### becomes empty or
RCS# becomes SCR. They must be un upper case.
                  Table 5.1: Section ID strings
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)Ecalot 12:30, 11 Aug 2005 (UTC)
  ID   Size in records
  ~~   12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)
  cust custom 
  font fonts
  fram frames
  palc CGA Palette
  pals SVGA Palette
  palt TGA Palette
  piec Pieces  
  psl  ? 
  scr  Screens (images that have the full screen)
  shap Shapes (normal graphics)
  shpl Shape palettes
  strl Str
  snd  Sound
  seqs Midi sequences
  txt4 Text

5.3. The slave indexes

All encapsulated sections are indexes.
The slave index is made with:
 - Offset SlaveIndexOffset,   size 2, type US: NumberOfItems
          (the number of the records referring to the file data)
 - Offset SlaveIndexOffset+2, size NumberOfItems*11: The slave index record
          (a list of NumberOfItems blocks of 11-bytes-length index record
          each corresponding to one slave index)
The 11-bytes-length slave index record (one per item): Size = 11 bytes
 - Relative offset 0, size 2, type US: Item ID
 - Relative offset 2, size 4, type UL: Resource start
          (absolute offset in file)
 - Relative offset 6, size 2, type US: Size of the item
          (not including the checksum byte)
 - Relative offset 8, size 3, type binary: A flags mask
          (in PAHS indexes it's allways 0x40 0x00 0x00;
          in others 0x00 0x00 0x00)


6. PLV v1.0 Format Specifications

PLV v1.0 files are defined in this table:
                  Table 6.1: PLV blocks
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~
  Size Offset Description                  Type   Content
  Ecalot 12:30, 11 Aug 2005 (UTC) 12:30, 11 Aug 2005 (UTC)~ 12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~                  Ecalot 12:30, 11 Aug 2005 (UTC)   12:30, 11 Aug 2005 (UTC)~~
     7      0 Magic identifier             text   "POP_LVL"
     1      7 POP version                  UC     0x01
     1      8 PLV version                  UC     0x01
     1      9 Level Number                 UC
     4     10 Number of fields             UL
     4     14 Block 1: Level size (B1)     UL     2306/2305
    B1     18 Block 1: Level code          -
     4  18+B1 Block 2: User data size (B2) UL
    B2  22+B1 Block 2: User data           -
Level code is the exact level as described in 4.4 including the checksum
byte. Note that Level size also includes the checksum byte in the count.
POP version is 1 for POP1 and 2 for POP2.
PLV version is 1 for PLV v1.0.
Only one level may be saved in a PLV, the level number is saved inside.

6.1. User data

User data is a block of extensible information, Number of fields is the
count of each field/value information pair. A pair is saved in the
following format:
 field_name\0value\0
where \0 is the null byte (0x00) and field_name and value are strings.
There are mandatory pairs that must be included in all PLV files.
Those are:
                  Table 6.2: Mandatory Fields
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~~
 Field name              Description
 12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)              12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~
 Editor Name             The name of the editor used to save the file
 Editor Version          The version of the editor used to save the file
 Level Author            The author of the file
 Level Title             A title for the level
 Level Description       A description
 Time Created            The time when the file was created
 Time Last Modified      The time of the last modification to the file
 Original Filename       The name of the original file name (levels.dat)
 Original Level Number   Optional. The level number it has when it was
                         first exported

The content values may be empty. There is no need to keep an order within
the fields.

6.2. Allowed Date format

To make easy time parsing the time format must be very strict.
There are only two allowed formats: with seconds and without.
With seconds the format is "YYYY-MM-DD HH:II:SS"
Without seconds the format is "YYYY-MM-DD HH:II"
Where YYYY is the year in 4 digits, MM is the month in numbers, MM the
months, DD the days, HH the hour, II the minute and SS the second in the
military time: HH is a number from 00 to 23.
If the month, day, hour or second have only one digit, the other digit
must be completed with 0.
i.e. 2002-11-26 22:16:39


7. The SAV v1.0 format

SAV v1.0 saves kid level, lives and remaining time information in order to
restart the game from this position.
SAV files are 8 bytes length in the following format:
                  Table 7.1: SAV blocks
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~
  Size Offset Description                  Type
  Ecalot 12:30, 11 Aug 2005 (UTC) 12:30, 11 Aug 2005 (UTC)~ 12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~                  Ecalot 12:30, 11 Aug 2005 (UTC)
     2      0 Remaining minutes            US   (i)
     2      2 Remaining ticks              US   (ii)
     2      4 Current level                US   (iii)
     2      6 Current hit points           US   (iv)
Remaining minutes (i)
 Range values:
  0     to 32766 for minutes
  32767 to 65534 for NO TIME (but the time is stored)
  65535 for game over
Remaining ticks (ii)
 Seconds are stored in ticks, a tick is 1/12 seconds. To get the time in
 seconds you have to divide the integer "Remaining ticks" by 12.
 Range values:
  0.000 to 59.916 seconds
                  (rounded by units of 83 milliseconds or 1/12 seconds)
  0     to 719    ticks
Level (iii)
 Range values:
  1  to 12 for normal levels
  13 for 12bis
  14 for princess level
  15 for potion level
Hit points (iv)
 Range values:
  0 for an immediate death
  1 to 65535 lives


8. The HOF v1.0 format

HOF files are used to save the Hall of Fame information.
All HOF v1.0 files have a size of 176 bytes. The first 2 bytes belongs to
the record count. The format is US. The maximum number of records allowed
is 6, so the second byte is allways 0x00.
Following those bytes there is an array of records. This array has a full
size of 29 bytes distributed according to the following table.
                  Table 8.1: HOF blocks
                  12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~
  Size Offset Description                  Type
  Ecalot 12:30, 11 Aug 2005 (UTC) 12:30, 11 Aug 2005 (UTC)~ 12:30, 11 Aug 2005 (UTC)12:30, 11 Aug 2005 (UTC)~                  Ecalot 12:30, 11 Aug 2005 (UTC)
    25      0 Player name                  text
     2     25 Remaining minutes            US (similar to SAV format)
     2     27 Remaining ticks              US (similar to SAV format)
In case there is no record, the 29 bytes spaces must be filled with zeros
in order to complete the whole file and give it the size of 2+29*6 = 176.


9. Credits

This document:
 Writing . . . . . . . . . . . . . . . . . . . . . . . . . Enrique Calot
 Corrections . . . . . . . . . . . . . . . . . . . . .  Patrik Jakobsson
Reverse Engineering:
 Indexes . . . . . . . . . . . . . . . . . . . . . . . . . Enrique Calot
 Levels . . . . . . . . . . . . . . . . . . . . . . . . .  Enrique Calot
                                                           Brendon James
 Images . . . . . . . . . . . . . . . . . . . . . . .  Tammo Jan Dijkema
 RLE Compression . . . . . . . . . . . . . . . . . . . Tammo Jan Dijkema
 LZG Compression . . . . . . . . . . . . . . . . . . . . . Anke Balderer
 Sounds . . . . . . . . . . . . . . . . . . . . . . . Christian Lundheim
PLV v1.0:
 Definition . . . . . . . . . . . . . . . . . . . . . . .  Brendon James
                                                           Enrique Calot

10. License

     Copyright (c)  2004, 2005 The Princed Project Team
     Permission is granted to copy, distribute and/or modify this document
     under the terms of the GNU Free Documentation License, Version 1.2
     or any later version published by the Free Software Foundation;
     with no Invariant Sections, no Front-Cover Texts, and no Back-Cover
     Texts.  A copy of the license is included in the section entitled
     "GNU Free Documentation License".