/**
* Serialize a pattern.
*
* @param pattern The pattern.
* @return The pattern in string form.
*/
public static String patternToString(List<LockPatternView.Cell> pattern) {
if (pattern == null) {
return "";
}
final int patternSize = pattern.size();
byte[] res = new byte[patternSize];
for (int i = 0; i < patternSize; i++) {
LockPatternView.Cell cell = pattern.get(i);
res[i] = (byte) (cell.getRow() * 3 + cell.getColumn());
}
return new String(res);
}
/**
* Deserialize a pattern.
*
* @param string The pattern serialized with {@link #patternToString}
* @return The pattern.
*/
public static List<LockPatternView.Cell> stringToPattern(String string) {
List<LockPatternView.Cell> result = Lists.newArrayList();
final byte[] bytes = string.getBytes();
for (int i = 0; i < bytes.length; i++) {
byte b = bytes[i];
result.add(LockPatternView.Cell.of(b / 3, b % 3));
}
return result;
}
/*
* Generate an SHA-1 hash for the pattern. Not the most secure, but it is
* at least a second level of protection. First level is that the file
* is in a location only readable by the system process.
* @param pattern the gesture pattern.
* @return the hash of the pattern in a byte array.
*/
@MiuiHook(MiuiHookType.CHANGE_ACCESS)
protected static byte[] patternToHash(List<LockPatternView.Cell> pattern) {
if (pattern == null) {
return null;
}
final int patternSize = pattern.size();
byte[] res = new byte[patternSize];
for (int i = 0; i < patternSize; i++) {
LockPatternView.Cell cell = pattern.get(i);
res[i] = (byte) (cell.getRow() * 3 + cell.getColumn());
}
try {
MessageDigest md = MessageDigest.getInstance("SHA-1");
byte[] hash = md.digest(res);
return hash;
} catch (NoSuchAlgorithmException nsa) {
return res;
}
}
