[DISCUSSION] mcc and mnc qualifiers

[IgorEisberg]

Just curious, is there any reason for this strange formatting of mcc and mnc qualifiers?
https://github.com/iBotPeaches/Apktool/blob/master/brut.apktool/apktool-lib/src/main/java/brut/androlib/res/data/ResConfigFlags.java#L179-L201

I mean, looking at the AOSP source code, there's a plain %d formatting for any value other than 0, no leading zeros.
https://android.googlesource.com/platform/frameworks/base/+/master/core/java/android/content/res/Configuration.java#2512
https://android.googlesource.com/platform/frameworks/base/+/master/libs/androidfw/ResourceTypes.cpp#3370

[iBotPeaches]

There is not - I'm guessing before AOSP source was out - this was the interpretation of how it functions. I might go back and look at the Froyo release to confirm that, but otherwise I don't think there is any Apktool specific reason.

[IgorEisberg]

I dug a bit deeper. This table gives these examples:

mcc310
mcc310-mnc004
mcc208-mnc00

Regarding mcc field: IMSI MCC (Mobile Country Code), corresponding to mcc resource qualifier. 0 if undefined.
Regarding mnc field: IMSI MNC (Mobile Network Code), corresponding to mnc resource qualifier. 0 if undefined. Note that the actual MNC may be 0; in order to check for this use the MNC_ZERO symbol.

Which seems to imply that stored value of MNC_ZERO is -mnc0/-mnc00/-mnc000, while stored value of 0 means any/undefined mnc.

Wikipedia says that MCC is always 3-digit, while MNC can be 2-digit (European standard) or 3-digit (North American standard), and an example says "MNC of 001 is not the same as MNC of 01".
Which is odd, because the source code I linked you to doesn't make any kind of differentiation when constructing the qualifiers, and both 001 and 01 are stored as 1.

Here's a partial output of aapt2 dump resources framework-res.apk | grep mcc | sort:

      (mcc286-mnc2) true
      (mcc286-mnc2) true
      (mcc286-mnc3) false
      (mcc286-mnc3) true
      (mcc286-mnc3) true
      (mcc295-mnc1) false
      (mcc295-mnc1) true
      (mcc295-mnc1) true
      (mcc302-mnc220) 1410
      (mcc302-mnc220) false
      (mcc302-mnc220) true
      (mcc302-mnc220) true
      (mcc302-mnc221) false
...
      (mcc520-mnc65535) true
      (mcc520-mnc65535) true
      (mcc520-mnc65535) true
      (mcc525-mnc1) false
      (mcc525-mnc1) true
      (mcc525-mnc1) true
      (mcc525-mnc17) 1380
      (mcc525-mnc3) false
      (mcc525-mnc3) false
      (mcc525-mnc3) true
      (mcc525-mnc5) false
      (mcc525-mnc5) false
      (mcc525-mnc5) true
      (mcc530-mnc24) false
      (mcc530-mnc24) false
      (mcc530-mnc24) true
      (mcc530-mnc5) false
      (mcc602-mnc1) false
      (mcc602-mnc1) true
      (mcc602-mnc1) true

1. We can see no leading zeros here at all.
2. It's known that -mnc65535 is -mnc0 (vs. undefined), because 65535==MNC_ZERO, but it's really either -mnc00 or -mnc000 (no way to know, 00 is used in Europe while 000 by One network in Bermuda).
3. For the rest, it's entirely unclear, e.g. does -mnc1 mean -mnc01 or -mnc001 when both are valid?

I'm very confused.

Eventually went with something that looks the best... (mnc doesn't appear without mcc before it, prints mnc as 2-digit or more)

        if (mcc != 0) {
            ret.append("-mcc").append(String.format("%03d", mcc));
            if (mnc != 0) {
                ret.append("-mnc");
                if (mnc != MNC_ZERO) {
                    ret.append(String.format("%02d", mnc));
                } else {
                    ret.append("00");
                }
            }
        }

So looks like this

-mcc001-mnc00
-mcc001-mnc01
...
-mcc001-mnc09
-mcc001-mnc10
-mcc001-mnc11
...
-mcc001-mnc99
-mcc001-mnc100
-mcc001-mnc101

[iBotPeaches]

Did you stumble onto some issue that led you to this? I'm just weary of changing something I haven't touched in a decade.

[IgorEisberg]

Nah, not really, just inconsistency in folder naming by some translators of our ROM. Had to think of some kind of standard format to present to them so they don't name it however they want and cause dirs with duplicate qualifiers. (AAPT2 ignores the leading zeros)