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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.server.wifi;
import android.text.TextUtils;
import com.android.internal.annotations.VisibleForTesting;
/**
* Class for storing an IMSI (International Mobile Subscriber Identity) parameter. The IMSI
* contains number (up to 15) of numerical digits. When an IMSI ends with a '*', the specified
* IMSI is a prefix.
*/
public class IMSIParameter {
/**
* Per 2.2 of 3GPP TS 23.003
* MCC (Mobile Country Code) is a 3 digit number and MNC (Mobile Network Code) is a 2
* or 3 digit number;
* The max length of IMSI is 15;
*/
public static final int MCC_MNC_LENGTH_5 = 5;
public static final int MCC_MNC_LENGTH_6 = 6;
private static final int MAX_IMSI_LENGTH = 15;
private final String mImsi;
private final boolean mPrefix;
@VisibleForTesting
public IMSIParameter(String imsi, boolean prefix) {
mImsi = imsi;
mPrefix = prefix;
}
/**
* Build an IMSIParameter object from the given string. A null will be returned for a
* malformed string.
*
* @param imsi The IMSI string
* @return {@link IMSIParameter}
*/
public static IMSIParameter build(String imsi) {
if (TextUtils.isEmpty(imsi)) {
return null;
}
if (imsi.length() > MAX_IMSI_LENGTH) {
return null;
}
// Detect the first non-digit character.
int nonDigitIndex;
char stopChar = '\0';
for (nonDigitIndex = 0; nonDigitIndex < imsi.length(); nonDigitIndex++) {
stopChar = imsi.charAt(nonDigitIndex);
if (stopChar < '0' || stopChar > '9') {
break;
}
}
if (nonDigitIndex == imsi.length()) {
// Full IMSI.
return new IMSIParameter(imsi, false);
} else if (nonDigitIndex == imsi.length() - 1 && stopChar == '*'
&& (nonDigitIndex == MCC_MNC_LENGTH_5 || nonDigitIndex == MCC_MNC_LENGTH_6)) {
// IMSI prefix.
return new IMSIParameter(imsi.substring(0, nonDigitIndex), true);
}
return null;
}
/**
* Perform matching against the given full IMSI.
*
* @param fullIMSI The full IMSI to match against
* @return true if matched
*/
public boolean matchesImsi(String fullIMSI) {
if (fullIMSI == null) {
return false;
}
if (mPrefix) {
// Prefix matching.
return mImsi.regionMatches(false, 0, fullIMSI, 0, mImsi.length());
} else {
// Exact matching.
return mImsi.equals(fullIMSI);
}
}
/**
* Perform matching against the given MCC-MNC (Mobile Country Code and Mobile Network
* Code) combination.
*
* @param mccMnc The MCC-MNC to match against
* @return true if matched
*/
public boolean matchesMccMnc(String mccMnc) {
if (mccMnc == null) {
return false;
}
if (mccMnc.length() != MCC_MNC_LENGTH_5 && mccMnc.length() != MCC_MNC_LENGTH_6) {
return false;
}
if (mPrefix && mccMnc.length() != mImsi.length()) {
return false;
}
return mImsi.startsWith(mccMnc);
}
/**
* If the IMSI is full length.
*
* @return true If the length of IMSI is full, false otherwise.
*/
public boolean isFullImsi() {
return !mPrefix;
}
@Override
public boolean equals(Object thatObject) {
if (this == thatObject) {
return true;
}
if (!(thatObject instanceof IMSIParameter)) {
return false;
}
IMSIParameter that = (IMSIParameter) thatObject;
return mPrefix == that.mPrefix && TextUtils.equals(mImsi, that.mImsi);
}
@Override
public int hashCode() {
int result = mImsi != null ? mImsi.hashCode() : 0;
result = 31 * result + (mPrefix ? 1 : 0);
return result;
}
@Override
public String toString() {
if (mPrefix) {
return mImsi + '*';
}
else {
return mImsi;
}
}
}
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