refactor: use kgm crypto from parakeet-rs

chore: update deps

algo/kgm/kgm_header.go

@@ -0,0 +1,64 @@
+package kgm
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+)
+
+var (
+	vprHeader = []byte{
+		0x05, 0x28, 0xBC, 0x96, 0xE9, 0xE4, 0x5A, 0x43,
+		0x91, 0xAA, 0xBD, 0xD0, 0x7A, 0xF5, 0x36, 0x31,
+	}
+	kgmHeader = []byte{
+		0x7C, 0xD5, 0x32, 0xEB, 0x86, 0x02, 0x7F, 0x4B,
+		0xA8, 0xAF, 0xA6, 0x8E, 0x0F, 0xFF, 0x99, 0x14,
+	}
+
+	ErrKgmMagicHeader = errors.New("kgm magic header not matched")
+)
+
+// Header is the header of a KGM file.
+type Header struct {
+	MagicHeader    []byte // 0x00-0x0f: magic header
+	AudioOffset    uint32 // 0x10-0x13: offset of audio data
+	CryptoVersion  uint32 // 0x14-0x17: crypto version
+	CryptoSlot     uint32 // 0x18-0x1b: crypto key slot
+	CryptoTestData []byte // 0x1c-0x2b: crypto test data
+	CryptoKey      []byte // 0x2c-0x3b: crypto key
+}
+
+func (h *Header) FromFile(rd io.ReadSeeker) error {
+	if _, err := rd.Seek(0, io.SeekStart); err != nil {
+		return fmt.Errorf("kgm seek start: %w", err)
+	}
+
+	buf := make([]byte, 0x3c)
+	if _, err := io.ReadFull(rd, buf); err != nil {
+		return fmt.Errorf("kgm read header: %w", err)
+	}
+
+	return h.FromBytes(buf)
+}
+
+func (h *Header) FromBytes(buf []byte) error {
+	if len(buf) < 0x3c {
+		return errors.New("invalid kgm header length")
+	}
+
+	h.MagicHeader = buf[:0x10]
+	if !bytes.Equal(kgmHeader, h.MagicHeader) && !bytes.Equal(vprHeader, h.MagicHeader) {
+		return ErrKgmMagicHeader
+	}
+
+	h.AudioOffset = binary.LittleEndian.Uint32(buf[0x10:0x14])
+	h.CryptoVersion = binary.LittleEndian.Uint32(buf[0x14:0x18])
+	h.CryptoSlot = binary.LittleEndian.Uint32(buf[0x18:0x1c])
+	h.CryptoTestData = buf[0x1c:0x2c]
+	h.CryptoKey = buf[0x2c:0x3c]
+
+	return nil
+}