public static byte[] Decompress(ReadStream compressed)
{
List <byte> decompressed = new List <byte>();
while (true)
{
// If an ff-byte is encountered the decompression has completed.
if (compressed.Peek() == LzEnd)
{
break;
}
// Bits 5-7 are occupied by control command.
int command = (compressed.Peek() & 0xe0) >> 5;
int length = 1;
// The long command is used when 5 bits aren't enough.
if (command == LzLong)
{
// Bits 2-4 contain the new control code.
command = (compressed.Peek() & 0x1c) >> 2;
// Bits 0-1 are appended to a new byte as bits 8-9, allowing a 10-bit operand.
length += (compressed.u8() & 0x3) << 8;
length += compressed.u8();
}
else
{
// If not a long command, bits 0-5 contain the command's operand.
length += (compressed.u8() & 0x1f);
}
switch (command)
{
case LzLiteral: Literal(compressed, decompressed, length); break;
case LzIterate: Iterate(compressed, decompressed, length); break;
case LzAlternate: Alternate(compressed, decompressed, length); break;
case LzBlank: Blank(compressed, decompressed, length); break;
case LzRepeat: Repeat(compressed, decompressed, length, 1, false); break;
case LzFlip: Repeat(compressed, decompressed, length, 1, true); break;
case LzReverse: Repeat(compressed, decompressed, length, -1, false); break;
}
}
return(decompressed.ToArray());
}
private void LoadSpecies()
{
const int maxIndexNumber = 190;
int numBaseStats = IsYellow ? 151 : 150;
byte[] pokedex = ROM.Subarray(SYM["PokedexOrder"], maxIndexNumber);
ReadStream data = ROM.From("BaseStats");
for (int i = 0; i < numBaseStats; i++)
{
byte indexNumber = (byte)Array.IndexOf(pokedex, data.Peek());
Species.Add(new RbySpecies(this, ++indexNumber, data));
}
if (this is RedBlue)
{
Species.Add(new RbySpecies(this, 21, ROM.From(SYM["MewBaseStats"])));
}
// Add MISSINGNO data
for (int i = 1; i <= maxIndexNumber; i++)
{
if (pokedex[i - 1] == 0)
{
RbySpecies species = new RbySpecies(this, (byte)i);
Species.Add(new RbySpecies(this, (byte)i));
}
}
}
public static void Repeat(ReadStream compressed, List <byte> decompressed, int length, int direction, bool flipped)
{
// Repeater commands repeat any data already present in the decompressed stream.
// They take an additional singed operand to mark the relative starting point.
int offset = 0;
if (compressed.Peek() >= 0x80)
{
// If the operand is negative, it wraps around from the current position.
offset = compressed.u8() & 0x7f;
offset = decompressed.Count - offset - 1;
}
else
{
// For positive operands, a 16-bit offset is used.
offset = compressed.u16be();
}
for (int i = 0; i < length; i++)
{
byte b = decompressed[offset + i * direction];
// Reverse the bits if the command desires it.
if (flipped)
{
b = (byte)(((b * 0x0802LU & 0x22110LU) | (b * 0x8020LU & 0x88440LU)) * 0x10101LU >> 16);
}
decompressed.Add(b);
}
}
