Parser for OLPC Manufacturing Data. http://wiki.laptop.org/go/Manufacturing_Data_Specification

ParseMfgData.java

package me.sheidy.mfgparse;

import java.nio.file.Files;
import java.nio.file.Paths;
import java.util.LinkedHashMap;
import java.util.Map;

public class ParseMfgData {

    public static Map<String, byte[]> parseMfgData(byte[] data) {
        Map<String, byte[]> values = new LinkedHashMap<>();

        for (int i = data.length - 1; i > 0; i--) {
            if (data[i] == (byte) 0xFF) break;

            char t2 = (char) data[i--];
            char t1 = (char) data[i--];

            String tag = new StringBuilder()
                    .append(t1)
                    .append(t2)
                    .toString();

            int len = data[i--];

            if (len >= 0 && len <= 127) { // 4-byte tag
                int check = data[i--];

                if (check == ~len) {
                    byte[] value = new byte[len];

                    for (int j = value.length-1; j >= 0; j--) {
                        value[j] = data[i--];
                    }
                    i++;

                    values.put(tag, value);

                    continue;
                }
            } else { // 5-byte tag
                int low_length = data[i--];
                int high_length = data[i--];

                byte check_byte = (byte) len;
                len = (high_length << 7) + low_length;

                byte calc_check = (byte) (low_length ^ high_length ^ 0xff);

                if (check_byte == calc_check) {
                    byte[] value = new byte[len];

                    for (int j = value.length-1; j >= 0; j--) {
                        value[j] = data[i--];
                    }
                    i++;

                    values.put(tag, value);

                    continue;
                }
            }

            System.err.println("error parsing tag: " + tag + " b: " + (byte)len);
            break;
        }

        return values;
    }

    /*******************************************************/

    public static void main(String[] args) throws Exception {
        if (args.length == 0) {
            System.out.println("No file specified");
            return;
        }

        byte[] data = Files.readAllBytes(Paths.get(args[0]));

        Map<String, byte[]> tags = parseMfgData(data);

        for (Map.Entry<String, byte[]> e : tags.entrySet()) {
            String tag = e.getKey();
            byte[] val = e.getValue();

            if (val.length == 0) { // boolean?
                System.out.println(tag + ":");
            } else if (val[val.length - 1] == 0) { // string
                System.out.println(tag + ": " + new String(val));
            } else { // binary
                System.out.println(tag + ": " + hex(val));
            }
        }
    }

    private static String hex(byte[] a) {
        StringBuilder sb = new StringBuilder();
        for (byte b : a) sb.append(String.format("%02x ", b));
        return sb.toString();
    }
}