SafeFileNameGenerator for UniversalImageLoader

SafeFileNameGenerator.java

import com.nostra13.universalimageloader.cache.disc.naming.FileNameGenerator;

/**
 * User: mcxiaoke
 * Date: 14-4-28
 * Time: 11:29
 */
public class SafeFileNameGenerator implements FileNameGenerator {

    @Override
    public String generate(final String imageUri) {
        return toSafeFileName(imageUri);
    }

    public static String toSafeFileName(String name) {
        int size = name.length();
        StringBuilder builder = new StringBuilder(size * 2);
        for (int i = 0; i < size; i++) {
            char c = name.charAt(i);
            boolean valid = c >= 'a' && c <= 'z';
            valid = valid || (c >= 'A' && c <= 'Z');
            valid = valid || (c >= '0' && c <= '9');
            valid = valid || (c == '_') || (c == '-') || (c == '.');

            if (valid) {
                builder.append(c);
            } else {
                // Encode the character using hex notation
                builder.append('x');
                builder.append(Integer.toHexString(i));
            }
        }
        return builder.toString();
    }
}