132 lines
3.1 KiB
Go
132 lines
3.1 KiB
Go
package d2mpq
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import (
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"encoding/binary"
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"io"
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"strings"
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)
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var cryptoBuffer [0x500]uint32 //nolint:gochecknoglobals // will fix later..
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var cryptoBufferReady bool //nolint:gochecknoglobals // will fix later..
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func cryptoLookup(index uint32) uint32 {
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if !cryptoBufferReady {
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cryptoInitialize()
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cryptoBufferReady = true
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}
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return cryptoBuffer[index]
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}
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//nolint:gomnd // Decryption magic
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func cryptoInitialize() {
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seed := uint32(0x00100001)
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for index1 := 0; index1 < 0x100; index1++ {
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index2 := index1
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for i := 0; i < 5; i++ {
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seed = (seed*125 + 3) % 0x2AAAAB
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temp1 := (seed & 0xFFFF) << 0x10
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seed = (seed*125 + 3) % 0x2AAAAB
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temp2 := seed & 0xFFFF
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cryptoBuffer[index2] = temp1 | temp2
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index2 += 0x100
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}
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}
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}
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//nolint:gomnd // Decryption magic
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func decrypt(data []uint32, seed uint32) {
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seed2 := uint32(0xeeeeeeee)
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for i := 0; i < len(data); i++ {
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seed2 += cryptoLookup(0x400 + (seed & 0xff))
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result := data[i]
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result ^= seed + seed2
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seed = ((^seed << 21) + 0x11111111) | (seed >> 11)
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seed2 = result + seed2 + (seed2 << 5) + 3
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data[i] = result
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}
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}
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//nolint:gomnd // Decryption magic
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func decryptBytes(data []byte, seed uint32) {
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seed2 := uint32(0xEEEEEEEE)
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for i := 0; i < len(data)-3; i += 4 {
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seed2 += cryptoLookup(0x400 + (seed & 0xFF))
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result := binary.LittleEndian.Uint32(data[i : i+4])
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result ^= seed + seed2
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seed = ((^seed << 21) + 0x11111111) | (seed >> 11)
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seed2 = result + seed2 + (seed2 << 5) + 3
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data[i+0] = uint8(result & 0xff)
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data[i+1] = uint8((result >> 8) & 0xff)
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data[i+2] = uint8((result >> 16) & 0xff)
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data[i+3] = uint8((result >> 24) & 0xff)
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}
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}
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//nolint:gomnd // Decryption magic
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func decryptTable(r io.Reader, size uint32, name string) ([]uint32, error) {
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seed := hashString(name, 3)
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seed2 := uint32(0xEEEEEEEE)
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size *= 4
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table := make([]uint32, size)
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buf := make([]byte, 4)
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for i := uint32(0); i < size; i++ {
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seed2 += cryptoBuffer[0x400+(seed&0xff)]
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if _, err := r.Read(buf); err != nil {
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return table, err
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}
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result := binary.LittleEndian.Uint32(buf)
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result ^= seed + seed2
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seed = ((^seed << 21) + 0x11111111) | (seed >> 11)
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seed2 = result + seed2 + (seed2 << 5) + 3
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table[i] = result
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}
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return table, nil
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}
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func hashFilename(key string) uint64 {
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a, b := hashString(key, 1), hashString(key, 2)
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return uint64(a)<<32 | uint64(b)
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}
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//nolint:gomnd // Decryption magic
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func hashString(key string, hashType uint32) uint32 {
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seed1 := uint32(0x7FED7FED)
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seed2 := uint32(0xEEEEEEEE)
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/* prepare seeds. */
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for _, char := range strings.ToUpper(key) {
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seed1 = cryptoLookup((hashType*0x100)+uint32(char)) ^ (seed1 + seed2)
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seed2 = uint32(char) + seed1 + seed2 + (seed2 << 5) + 3
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}
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return seed1
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}
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//nolint:unused,deadcode,gomnd // will use this for creating mpq's
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func encrypt(data []uint32, seed uint32) {
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seed2 := uint32(0xeeeeeeee)
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for i := 0; i < len(data); i++ {
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seed2 += cryptoLookup(0x400 + (seed & 0xff))
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result := data[i]
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result ^= seed + seed2
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seed = ((^seed << 21) + 0x11111111) | (seed >> 11)
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seed2 = data[i] + seed2 + (seed2 << 5) + 3
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data[i] = result
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}
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}
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