android/telephony/PhoneNumberUtils.java

/*
 * Copyright (C) 2006 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 android.telephony;

import android.content.Context;
import android.content.Intent;
import android.database.Cursor;
import android.net.Uri;
import android.os.SystemProperties;
import android.provider.Contacts;
import android.text.Editable;
import android.text.SpannableStringBuilder;
import android.text.TextUtils;
import android.util.SparseIntArray;

import java.util.Locale;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Various utilities for dealing with phone number strings.
 */
public class PhoneNumberUtils
{
    /*
     * Special characters
     *
     * (See "What is a phone number?" doc)
     * 'p' --- GSM pause character, same as comma
     * 'n' --- GSM wild character
     * 'w' --- GSM wait character
     */
    public static final char PAUSE = ',';
    public static final char WAIT = ';';
    public static final char WILD = 'N';

    /*
     * TOA = TON + NPI
     * See TS 24.008 section 10.5.4.7 for details.
     * These are the only really useful TOA values
     */
    public static final int TOA_International = 0x91;
    public static final int TOA_Unknown = 0x81;

    /*
     * global-phone-number = ["+"] 1*( DIGIT / written-sep )
     * written-sep         = ("-"/".")
     */
    private static final Pattern GLOBAL_PHONE_NUMBER_PATTERN =
            Pattern.compile("[\\+]?[0-9.-]+");

    /** True if c is ISO-LATIN characters 0-9 */
    public static boolean
    isISODigit (char c) {
        return c >= '0' && c <= '9';
    }

    /** True if c is ISO-LATIN characters 0-9, *, # */
    public final static boolean
    is12Key(char c) {
        return (c >= '0' && c <= '9') || c == '*' || c == '#';
    }

    /** True if c is ISO-LATIN characters 0-9, *, # , +, WILD  */
    public final static boolean
    isDialable(char c) {
        return (c >= '0' && c <= '9') || c == '*' || c == '#' || c == '+' || c == WILD;
    }

    /** True if c is ISO-LATIN characters 0-9, *, # , + (no WILD)  */
    public final static boolean
    isReallyDialable(char c) {
        return (c >= '0' && c <= '9') || c == '*' || c == '#' || c == '+';
    }

    /** True if c is ISO-LATIN characters 0-9, *, # , +, WILD, WAIT, PAUSE   */
    public final static boolean
    isNonSeparator(char c) {
        return (c >= '0' && c <= '9') || c == '*' || c == '#' || c == '+'
                || c == WILD || c == WAIT || c == PAUSE;
    }

    /** This any anything to the right of this char is part of the
     *  post-dial string (eg this is PAUSE or WAIT)
     */
    public final static boolean
    isStartsPostDial (char c) {
        return c == PAUSE || c == WAIT;
    }

    /** Extracts the phone number from an Intent.
     *
     * @param intent the intent to get the number of
     * @param context a context to use for database access
     *
     * @return the phone number that would be called by the intent, or
     *         <code>null</code> if the number cannot be found.
     */
    public static String getNumberFromIntent(Intent intent, Context context) {
        String number = null;

        Uri uri = intent.getData();
        String scheme = uri.getScheme();

        if (scheme.equals("tel")) {
            return uri.getSchemeSpecificPart();
        }

        if (scheme.equals("voicemail")) {
            return TelephonyManager.getDefault().getVoiceMailNumber();
        }

        if (context == null) {
            return null;
        }

        String type = intent.resolveType(context);

        Cursor c = context.getContentResolver().query(
                uri, new String[]{ Contacts.People.Phones.NUMBER },
                null, null, null);
        if (c != null) {
            try {
                if (c.moveToFirst()) {
                    number = c.getString(
                            c.getColumnIndex(Contacts.People.Phones.NUMBER));
                }
            } finally {
                c.close();
            }
        }

        return number;
    }

    /** Extracts the network address portion and canonicalizes
     *  (filters out separators.)
     *  Network address portion is everything up to DTMF control digit
     *  separators (pause or wait), but without non-dialable characters.
     *
     *  Please note that the GSM wild character is allowed in the result.
     *  This must be resolved before dialing.
     *
     *  Allows + only in the first  position in the result string.
     *
     *  Returns null if phoneNumber == null
     */
    public static String
    extractNetworkPortion(String phoneNumber) {
        if (phoneNumber == null) {
            return null;
        }

        int len = phoneNumber.length();
        StringBuilder ret = new StringBuilder(len);
        boolean firstCharAdded = false;

        for (int i = 0; i < len; i++) {
            char c = phoneNumber.charAt(i);
            if (isDialable(c) && (c != '+' || !firstCharAdded)) {
                firstCharAdded = true;
                ret.append(c);
            } else if (isStartsPostDial (c)) {
                break;
            }
        }

        return ret.toString();
    }

    /**
     * Strips separators from a phone number string.
     * @param phoneNumber phone number to strip.
     * @return phone string stripped of separators.
     */
    public static String stripSeparators(String phoneNumber) {
        if (phoneNumber == null) {
            return null;
        }
        int len = phoneNumber.length();
        StringBuilder ret = new StringBuilder(len);

        for (int i = 0; i < len; i++) {
            char c = phoneNumber.charAt(i);
            if (isNonSeparator(c)) {
                ret.append(c);
            }
        }

        return ret.toString();
    }

    /** or -1 if both are negative */
    static private int
    minPositive (int a, int b) {
        if (a >= 0 && b >= 0) {
            return (a < b) ? a : b;
        } else if (a >= 0) { /* && b < 0 */
            return a;
        } else if (b >= 0) { /* && a < 0 */
            return b;
        } else { /* a < 0 && b < 0 */
            return -1;
        }
    }

    /** index of the last character of the network portion
     *  (eg anything after is a post-dial string)
     */
    static private int
    indexOfLastNetworkChar(String a) {
        int pIndex, wIndex;
        int origLength;
        int trimIndex;

        origLength = a.length();

        pIndex = a.indexOf(PAUSE);
        wIndex = a.indexOf(WAIT);

        trimIndex = minPositive(pIndex, wIndex);

        if (trimIndex < 0) {
            return origLength - 1;
        } else {
            return trimIndex - 1;
        }
    }

    /**
     * Extracts the post-dial sequence of DTMF control digits, pauses, and
     * waits. Strips separators. This string may be empty, but will not be null
     * unless phoneNumber == null.
     *
     * Returns null if phoneNumber == null
     */

    public static String
    extractPostDialPortion(String phoneNumber) {
        if (phoneNumber == null) return null;

        int trimIndex;
        StringBuilder ret = new StringBuilder();

        trimIndex = indexOfLastNetworkChar (phoneNumber);

        for (int i = trimIndex + 1, s = phoneNumber.length()
                ; i < s; i++
        ) {
            char c = phoneNumber.charAt(i);
            if (isNonSeparator(c)) {
                ret.append(c);
            }
        }

        return ret.toString();
    }

    /**
     * Compare phone numbers a and b, return true if they're identical
     * enough for caller ID purposes.
     *
     * - Compares from right to left
     * - requires MIN_MATCH (5) characters to match
     * - handles common trunk prefixes and international prefixes
     *   (basically, everything except the Russian trunk prefix)
     *
     * Tolerates nulls
     */
    public static boolean
    compare(String a, String b) {
        int ia, ib;
        int matched;

        if (a == null || b == null) return a == b;

        if (a.length() == 0 || b.length() == 0) {
            return false;
        }

        ia = indexOfLastNetworkChar (a);
        ib = indexOfLastNetworkChar (b);
        matched = 0;

        while (ia >= 0 && ib >=0) {
            char ca, cb;
            boolean skipCmp = false;

            ca = a.charAt(ia);

            if (!isDialable(ca)) {
                ia--;
                skipCmp = true;
            }

            cb = b.charAt(ib);

            if (!isDialable(cb)) {
                ib--;
                skipCmp = true;
            }

            if (!skipCmp) {
                if (cb != ca && ca != WILD && cb != WILD) {
                    break;
                }
                ia--; ib--; matched++;
            }
        }

        if (matched < MIN_MATCH) {
            int aLen = a.length();

            // if the input strings match, but their lengths < MIN_MATCH,
            // treat them as equal.
            if (aLen == b.length() && aLen == matched) {
                return true;
            }
            return false;
        }

        // At least one string has matched completely;
        if (matched >= MIN_MATCH && (ia < 0 || ib < 0)) {
            return true;
        }

        /*
         * Now, what remains must be one of the following for a
         * match:
         *
         *  - a '+' on one and a '00' or a '011' on the other
         *  - a '0' on one and a (+,00)<country code> on the other
         *     (for this, a '0' and a '00' prefix would have succeeded above)
         */

        if (matchIntlPrefix(a, ia + 1)
            && matchIntlPrefix (b, ib +1)
        ) {
            return true;
        }

        if (matchTrunkPrefix(a, ia + 1)
            && matchIntlPrefixAndCC(b, ib +1)
        ) {
            return true;
        }

        if (matchTrunkPrefix(b, ib + 1)
            && matchIntlPrefixAndCC(a, ia +1)
        ) {
            return true;
        }

        return false;
    }

    /**
     * Returns the rightmost MIN_MATCH (5) characters in the network portion
     * in *reversed* order
     *
     * This can be used to do a database lookup against the column
     * that stores getStrippedReversed()
     *
     * Returns null if phoneNumber == null
     */
    public static String
    toCallerIDMinMatch(String phoneNumber) {
        String np = extractNetworkPortion(phoneNumber);
        return internalGetStrippedReversed(np, MIN_MATCH);
    }

    /**
     * Returns the network portion reversed.
     * This string is intended to go into an index column for a
     * database lookup.
     *
     * Returns null if phoneNumber == null
     */
    public static String
    getStrippedReversed(String phoneNumber) {
        String np = extractNetworkPortion(phoneNumber);

        if (np == null) return null;

        return internalGetStrippedReversed(np, np.length());
    }

    /**
     * Returns the last numDigits of the reversed phone number
     * Returns null if np == null
     */
    private static String
    internalGetStrippedReversed(String np, int numDigits) {
        if (np == null) return null;

        StringBuilder ret = new StringBuilder(numDigits);
        int length = np.length();

        for (int i = length - 1, s = length
            ; i >= 0 && (s - i) <= numDigits ; i--
        ) {
            char c = np.charAt(i);

            ret.append(c);
        }

        return ret.toString();
    }

    /**
     * Basically: makes sure there's a + in front of a
     * TOA_International number
     *
     * Returns null if s == null
     */
    public static String
    stringFromStringAndTOA(String s, int TOA) {
        if (s == null) return null;

        if (TOA == TOA_International && s.length() > 0 && s.charAt(0) != '+') {
            return "+" + s;
        }

        return s;
    }

    /**
     * Returns the TOA for the given dial string
     * Basically, returns TOA_International if there's a + prefix
     */

    public static int
    toaFromString(String s) {
        if (s != null && s.length() > 0 && s.charAt(0) == '+') {
            return TOA_International;
        }

        return TOA_Unknown;
    }

    /**
     * Phone numbers are stored in "lookup" form in the database
     * as reversed strings to allow for caller ID lookup
     *
     * This method takes a phone number and makes a valid SQL "LIKE"
     * string that will match the lookup form
     *
     */
    /** all of a up to len must be an international prefix or
     *  separators/non-dialing digits
     */
    private static boolean
    matchIntlPrefix(String a, int len) {
        /* '([^0-9*#+pwn]\+[^0-9*#+pwn] | [^0-9*#+pwn]0(0|11)[^0-9*#+pwn] )$' */
        /*        0       1                           2 3 45               */

        int state = 0;
        for (int i = 0 ; i < len ; i++) {
            char c = a.charAt(i);

            switch (state) {
                case 0:
                    if      (c == '+') state = 1;
                    else if (c == '0') state = 2;
                    else if (isNonSeparator(c)) return false;
                break;

                case 2:
                    if      (c == '0') state = 3;
                    else if (c == '1') state = 4;
                    else if (isNonSeparator(c)) return false;
                break;

                case 4:
                    if      (c == '1') state = 5;
                    else if (isNonSeparator(c)) return false;
                break;

                default:
                    if (isNonSeparator(c)) return false;
                break;

            }
        }

        return state == 1 || state == 3 || state == 5;
    }

    /**
     *  3GPP TS 24.008 10.5.4.7
     *  Called Party BCD Number
     *
     *  See Also TS 51.011 10.5.1 "dialing number/ssc string"
     *
     * @param bytes the data buffer
     * @param offset should point to the TOI/NPI octet after the length byte
     * @param length is the number of bytes including TOA byte
     *                and must be at least 2
     *
     * @return partial string on invalid decode
     *
     * FIXME(mkf) support alphanumeric address type
     *  currently implemented in SMSMessage.getAddress()
     */
    public static String
    calledPartyBCDToString (byte[] bytes, int offset, int length) {
        boolean prependedPlus = false;
        StringBuilder ret = new StringBuilder(1 + length * 2);

        if (length < 2) {
            return "";
        }

        if ((bytes[offset] & 0xff) == TOA_International) {
            ret.append("+");
            prependedPlus = true;
        }

        internalCalledPartyBCDFragmentToString(
                ret, bytes, offset + 1, length - 1);

        if (prependedPlus && ret.length() == 1) {
            // If the only thing there is a prepended plus, return ""
            return "";
        }

        return ret.toString();
    }

    private static void
    internalCalledPartyBCDFragmentToString(
        StringBuilder sb, byte [] bytes, int offset, int length) {
        for (int i = offset ; i < length + offset ; i++) {
            byte b;
            char c;

            c = bcdToChar((byte)(bytes[i] & 0xf));

            if (c == 0) {
                return;
            }
            sb.append(c);

            // FIXME(mkf) TS 23.040 9.1.2.3 says
            // "if a mobile receives 1111 in a position prior to
            // the last semi-octet then processing shall commense with
            // the next semi-octet and the intervening
            // semi-octet shall be ignored"
            // How does this jive with 24,008 10.5.4.7

            b = (byte)((bytes[i] >> 4) & 0xf);

            if (b == 0xf && i + 1 == length + offset) {
                //ignore final 0xf
                break;
            }

            c = bcdToChar(b);
            if (c == 0) {
                return;
            }

            sb.append(c);
        }

    }

    /**
     * Like calledPartyBCDToString, but field does not start with a
     * TOA byte. For example: SIM ADN extension fields
     */

    public static String
    calledPartyBCDFragmentToString(byte [] bytes, int offset, int length) {
        StringBuilder ret = new StringBuilder(length * 2);

        internalCalledPartyBCDFragmentToString(ret, bytes, offset, length);

        return ret.toString();
    }

    /** returns 0 on invalid value */
    private static char
    bcdToChar(byte b) {
        if (b < 0xa) {
            return (char)('0' + b);
        } else switch (b) {
            case 0xa: return '*';
            case 0xb: return '#';
            case 0xc: return PAUSE;
            case 0xd: return WILD;

            default: return 0;
        }
    }

    private static int
    charToBCD(char c) {
        if (c >= '0' && c <= '9') {
            return c - '0';
        } else if (c == '*') {
            return 0xa;
        } else if (c == '#') {
            return 0xb;
        } else if (c == PAUSE) {
            return 0xc;
        } else if (c == WILD) {
            return 0xd;
        } else {
            throw new RuntimeException ("invalid char for BCD " + c);
        }
    }

    /**
     * Note: calls extractNetworkPortion(), so do not use for
     * SIM EF[ADN] style records
     *
     * Exceptions thrown if extractNetworkPortion(s).length() == 0
     */
    public static byte[]
    networkPortionToCalledPartyBCD(String s) {
        return numberToCalledPartyBCD(extractNetworkPortion(s));
    }

    /**
     * Return true iff the network portion of <code>address</code> is,
     * as far as we can tell on the device, suitable for use as an SMS
     * destination address.
     */
    public static boolean isWellFormedSmsAddress(String address) {
        String networkPortion =
                PhoneNumberUtils.extractNetworkPortion(address);

        return (!(networkPortion.equals("+")
                  || TextUtils.isEmpty(networkPortion)))
               && isDialable(networkPortion);
    }

    public static boolean isGlobalPhoneNumber(String phoneNumber) {
        if (TextUtils.isEmpty(phoneNumber)) {
            return false;
        }

        Matcher match = GLOBAL_PHONE_NUMBER_PATTERN.matcher(phoneNumber);
        return match.matches();
    }

    private static boolean isDialable(String address) {
        for (int i = 0, count = address.length(); i < count; i++) {
            if (!isDialable(address.charAt(i))) {
                return false;
            }
        }
        return true;
    }

    /**
     * Same as {@link #networkPortionToCalledPartyBCD}, but includes a
     * one-byte length prefix.
     */
    public static byte[]
    networkPortionToCalledPartyBCDWithLength(String s) {
        return numberToCalledPartyBCDWithLength(extractNetworkPortion(s));
    }

    /**
     * Convert a dialing number to BCD byte array
     *
     * @param number dialing number string
     *        if the dialing number starts with '+', set to internationl TOA
     * @return BCD byte array
     */
    public static byte[]
    numberToCalledPartyBCD(String number) {
        // The extra byte required for '+' is taken into consideration while calculating
        // length of ret.
        int size = ((number.charAt(0) == '+') ? number.length() - 1 : number.length());
        byte[] ret = new byte[(size + 1) / 2 + 1];

        return numberToCalledPartyBCDHelper(ret, 0, number);
    }

    /**
     * Same as {@link #numberToCalledPartyBCD}, but includes a
     * one-byte length prefix.
     */
    private static byte[]
    numberToCalledPartyBCDWithLength(String number) {
        // The extra byte required for '+' is taken into consideration while calculating
        // length of ret.
        int size = ((number.charAt(0) == '+') ? number.length() - 1 : number.length());
        int length = (size + 1) / 2 + 1;
        byte[] ret = new byte[length + 1];

        ret[0] = (byte) (length & 0xff);
        return numberToCalledPartyBCDHelper(ret, 1, number);
    }

    private static byte[]
    numberToCalledPartyBCDHelper(byte[] ret, int offset, String number) {
        int size;
        int curChar;

        size = number.length();

        if (number.charAt(0) == '+') {
            curChar = 1;
            ret[offset] = (byte) TOA_International;
        } else {
            curChar = 0;
            ret[offset] = (byte) TOA_Unknown;
        }

        int countFullBytes = ret.length - offset - 1 - ((size - curChar) & 1);
        for (int i = 1; i < 1 + countFullBytes; i++) {
            ret[offset + i]
                    = (byte) ((charToBCD(number.charAt(curChar++)))
                              | (charToBCD(number.charAt(curChar++))) << 4);
        }

        // The left-over octet for odd-length phone numbers should be
        // filled with 0xf.
        if (countFullBytes + offset < ret.length - 1) {
            ret[ret.length - 1]
                    = (byte) (charToBCD(number.charAt(curChar))
                              | (0xf << 4));
        }
        return ret;
    }

    /** all of 'a' up to len must match non-US trunk prefix ('0') */
    private static boolean
    matchTrunkPrefix(String a, int len) {
        boolean found;

        found = false;

        for (int i = 0 ; i < len ; i++) {
            char c = a.charAt(i);

            if (c == '0' && !found) {
                found = true;
            } else if (isNonSeparator(c)) {
                return false;
            }
        }

        return found;
    }

    /** all of 'a' up to len must be a (+|00|011)country code)
     *  We're fast and loose with the country code. Any \d{1,3} matches */
    private static boolean
    matchIntlPrefixAndCC(String a, int len) {
        /*  [^0-9*#+pwn]*(\+|0(0|11)\d\d?\d? [^0-9*#+pwn] $ */
        /*      0          1 2 3 45  6 7  8                 */

        int state = 0;
        for (int i = 0 ; i < len ; i++ ) {
            char c = a.charAt(i);

            switch (state) {
                case 0:
                    if      (c == '+') state = 1;
                    else if (c == '0') state = 2;
                    else if (isNonSeparator(c)) return false;
                break;

                case 2:
                    if      (c == '0') state = 3;
                    else if (c == '1') state = 4;
                    else if (isNonSeparator(c)) return false;
                break;

                case 4:
                    if      (c == '1') state = 5;
                    else if (isNonSeparator(c)) return false;
                break;

                case 1:
                case 3:
                case 5:
                    if      (isISODigit(c)) state = 6;
                    else if (isNonSeparator(c)) return false;
                break;

                case 6:
                case 7:
                    if      (isISODigit(c)) state++;
                    else if (isNonSeparator(c)) return false;
                break;

                default:
                    if (isNonSeparator(c)) return false;
            }
        }

        return state == 6 || state == 7 || state == 8;
    }

    //================ Number formatting =========================

    /** The current locale is unknown, look for a country code or don't format */
    public static final int FORMAT_UNKNOWN = 0;
    /** NANP formatting */
    public static final int FORMAT_NANP = 1;

    /** List of country codes for countries that use the NANP */
    private static final String[] NANP_COUNTRIES = new String[] {
        "US", // United States
        "CA", // Canada
        "AS", // American Samoa
        "AI", // Anguilla
        "AG", // Antigua and Barbuda
        "BS", // Bahamas
        "BB", // Barbados
        "BM", // Bermuda
        "VG", // British Virgin Islands
        "KY", // Cayman Islands
        "DM", // Dominica
        "DO", // Dominican Republic
        "GD", // Grenada
        "GU", // Guam
        "JM", // Jamaica
        "PR", // Puerto Rico
        "MS", // Montserrat
        "NP", // Northern Mariana Islands
        "KN", // Saint Kitts and Nevis
        "LC", // Saint Lucia
        "VC", // Saint Vincent and the Grenadines
        "TT", // Trinidad and Tobago
        "TC", // Turks and Caicos Islands
        "VI", // U.S. Virgin Islands
    };

    /**
     * Breaks the given number down and formats it according to the rules
     * for the country the number is from.
     *
     * @param source the phone number to format
     * @return a locally acceptable formatting of the input, or the raw input if
     *  formatting rules aren't known for the number
     */
    public static String formatNumber(String source) {
        SpannableStringBuilder text = new SpannableStringBuilder(source);
        formatNumber(text, getFormatTypeForLocale(Locale.getDefault()));
        return text.toString();
    }

    /**
     * Returns the phone number formatting type for the given locale.
     *
     * @param locale The locale of interest, usually {@link Locale#getDefault()}
     * @return the formatting type for the given locale, or FORMAT_UNKNOWN if the formatting
     * rules are not known for the given locale
     */
    public static int getFormatTypeForLocale(Locale locale) {
        String country = locale.getCountry();

        // Check for the NANP countries
        int length = NANP_COUNTRIES.length;
        for (int i = 0; i < length; i++) {
            if (NANP_COUNTRIES[i].equals(country)) {
                return FORMAT_NANP;
            }
        }
        return FORMAT_UNKNOWN;
    }

    /**
     * Formats a phone number in-place. Currently only supports NANP formatting.
     *
     * @param text The number to be formatted, will be modified with the formatting
     * @param defaultFormattingType The default formatting rules to apply if the number does
     * not begin with +<country_code>
     */
    public static void formatNumber(Editable text, int defaultFormattingType) {
        int formatType = defaultFormattingType;

        // This only handles +1 for now
        if (text.length() > 2 && text.charAt(0) == '+') {
            if (text.charAt(1) == '1') {
                formatType = FORMAT_NANP;
            } else {
                return;
            }
        }

        switch (formatType) {
            case FORMAT_NANP:
                formatNanpNumber(text);
                return;
        }
    }

    private static final int NANP_STATE_DIGIT = 1;
    private static final int NANP_STATE_PLUS = 2;
    private static final int NANP_STATE_ONE = 3;
    private static final int NANP_STATE_DASH = 4;

    /**
     * Formats a phone number in-place using the NANP formatting rules. Numbers will be formatted
     * as:
     *
     * <p><code>
     * xxx-xxxx
     * xxx-xxx-xxxx
     * 1-xxx-xxx-xxxx
     * +1-xxx-xxx-xxxx
     * </code></p>
     *
     * @param text the number to be formatted, will be modified with the formatting
     */
    public static void formatNanpNumber(Editable text) {
        int length = text.length();
        if (length > "+1-nnn-nnn-nnnn".length()) {
            // The string is too long to be formatted
            return;
        }
        CharSequence saved = text.subSequence(0, length);

        // Strip the dashes first, as we're going to add them back
        int p = 0;
        while (p < text.length()) {
            if (text.charAt(p) == '-') {
                text.delete(p, p + 1);
            } else {
                p++;
            }
        }
        length = text.length();

        // When scanning the number we record where dashes need to be added,
        // if they're non-0 at the end of the scan the dashes will be added in
        // the proper places.
        int dashPositions[] = new int[3];
        int numDashes = 0;

        int state = NANP_STATE_DIGIT;
        int numDigits = 0;
        for (int i = 0; i < length; i++) {
            char c = text.charAt(i);
            switch (c) {
                case '1':
                    if (numDigits == 0 || state == NANP_STATE_PLUS) {
                        state = NANP_STATE_ONE;
                        break;
                    }
                    // fall through
                case '2':
                case '3':
                case '4':
                case '5':
                case '6':
                case '7':
                case '8':
                case '9':
                case '0':
                    if (state == NANP_STATE_PLUS) {
                        // Only NANP number supported for now
                        text.replace(0, length, saved);
                        return;
                    } else if (state == NANP_STATE_ONE) {
                        // Found either +1 or 1, follow it up with a dash
                        dashPositions[numDashes++] = i;
                    } else if (state != NANP_STATE_DASH && (numDigits == 3 || numDigits == 6)) {
                        // Found a digit that should be after a dash that isn't
                        dashPositions[numDashes++] = i;
                    }
                    state = NANP_STATE_DIGIT;
                    numDigits++;
                    break;

                case '-':
                    state = NANP_STATE_DASH;
                    break;

                case '+':
                    if (i == 0) {
                        // Plus is only allowed as the first character
                        state = NANP_STATE_PLUS;
                        break;
                    }
                    // Fall through
                default:
                    // Unknown character, bail on formatting
                    text.replace(0, length, saved);
                    return;
            }
        }

        if (numDigits == 7) {
            // With 7 digits we want xxx-xxxx, not xxx-xxx-x
            numDashes--;
        }

        // Actually put the dashes in place
        for (int i = 0; i < numDashes; i++) {
            int pos = dashPositions[i];
            text.replace(pos + i, pos + i, "-");
        }

        // Remove trailing dashes
        int len = text.length();
        while (len > 0) {
            if (text.charAt(len - 1) == '-') {
                text.delete(len - 1, len);
                len--;
            } else {
                break;
            }
        }
    }

    // Three and four digit phone numbers for either special services
    // or from the network (eg carrier-originated SMS messages) should
    // not match
    static final int MIN_MATCH = 5;

    /**
     * isEmergencyNumber: checks a given number against the list of
     *   emergency numbers provided by the RIL and SIM card.
     *
     * @param number the number to look up.
     * @return if the number is in the list of emergency numbers
     * listed in the ril / sim, then return true, otherwise false.
     */
    public static boolean isEmergencyNumber(String number) {
        // Strip the separators from the number before comparing it
        // to the list.
        number = extractNetworkPortion(number);

        // retrieve the list of emergency numbers
        String numbers = SystemProperties.get("ro.ril.ecclist");

        if (!TextUtils.isEmpty(numbers)) {
            // searches through the comma-separated list for a match,
            // return true if one is found.
            for (String emergencyNum : numbers.split(",")) {
                if (emergencyNum.equals(number)) {
                    return true;
                }
            }
            // no matches found against the list!
            return false;
        }

        //no ecclist system property, so use our own list.
        return (number.equals("112") || number.equals("911"));
    }

    /**
     * Translates any alphabetic letters (i.e. [A-Za-z]) in the
     * specified phone number into the equivalent numeric digits,
     * according to the phone keypad letter mapping described in
     * ITU E.161 and ISO/IEC 9995-8.
     *
     * @return the input string, with alpha letters converted to numeric
     *         digits using the phone keypad letter mapping.  For example,
     *         an input of "1-800-GOOG-411" will return "1-800-4664-411".
     */
    public static String convertKeypadLettersToDigits(String input) {
        if (input == null) {
            return input;
        }
        int len = input.length();
        if (len == 0) {
            return input;
        }

        char[] out = input.toCharArray();

        for (int i = 0; i < len; i++) {
            char c = out[i];
            // If this char isn't in KEYPAD_MAP at all, just leave it alone.
            out[i] = (char) KEYPAD_MAP.get(c, c);
        }

        return new String(out);
    }

    /**
     * The phone keypad letter mapping (see ITU E.161 or ISO/IEC 9995-8.)
     * TODO: This should come from a resource.
     */
    private static final SparseIntArray KEYPAD_MAP = new SparseIntArray();
    static {
        KEYPAD_MAP.put('a', '2'); KEYPAD_MAP.put('b', '2'); KEYPAD_MAP.put('c', '2');
        KEYPAD_MAP.put('A', '2'); KEYPAD_MAP.put('B', '2'); KEYPAD_MAP.put('C', '2');

        KEYPAD_MAP.put('d', '3'); KEYPAD_MAP.put('e', '3'); KEYPAD_MAP.put('f', '3');
        KEYPAD_MAP.put('D', '3'); KEYPAD_MAP.put('E', '3'); KEYPAD_MAP.put('F', '3');

        KEYPAD_MAP.put('g', '4'); KEYPAD_MAP.put('h', '4'); KEYPAD_MAP.put('i', '4');
        KEYPAD_MAP.put('G', '4'); KEYPAD_MAP.put('H', '4'); KEYPAD_MAP.put('I', '4');

        KEYPAD_MAP.put('j', '5'); KEYPAD_MAP.put('k', '5'); KEYPAD_MAP.put('l', '5');
        KEYPAD_MAP.put('J', '5'); KEYPAD_MAP.put('K', '5'); KEYPAD_MAP.put('L', '5');

        KEYPAD_MAP.put('m', '6'); KEYPAD_MAP.put('n', '6'); KEYPAD_MAP.put('o', '6');
        KEYPAD_MAP.put('M', '6'); KEYPAD_MAP.put('N', '6'); KEYPAD_MAP.put('O', '6');

        KEYPAD_MAP.put('p', '7'); KEYPAD_MAP.put('q', '7'); KEYPAD_MAP.put('r', '7'); KEYPAD_MAP.put('s', '7');
        KEYPAD_MAP.put('P', '7'); KEYPAD_MAP.put('Q', '7'); KEYPAD_MAP.put('R', '7'); KEYPAD_MAP.put('S', '7');

        KEYPAD_MAP.put('t', '8'); KEYPAD_MAP.put('u', '8'); KEYPAD_MAP.put('v', '8');
        KEYPAD_MAP.put('T', '8'); KEYPAD_MAP.put('U', '8'); KEYPAD_MAP.put('V', '8');

        KEYPAD_MAP.put('w', '9'); KEYPAD_MAP.put('x', '9'); KEYPAD_MAP.put('y', '9'); KEYPAD_MAP.put('z', '9');
        KEYPAD_MAP.put('W', '9'); KEYPAD_MAP.put('X', '9'); KEYPAD_MAP.put('Y', '9'); KEYPAD_MAP.put('Z', '9');
    }
}