Enable support for SMS national language shift tables.

Add support for encoding and decoding SMS 7 bit user data using the
national language shift tables defined in 3GPP TS 23.038 (GSM/UMTS only),
including the new tables added in Release 9 for Indic languages.

Decoding is always supported, but encoding is only enabled for the
specific language tables added to the new integer array resources
"config_sms_enabled_single_shift_tables" and
"config_sms_enabled_locking_shift_tables" defined in
frameworks/base/core/res/res/values/config.xml. The default empty arrays
should be overridden in an OEM overlay for the specific nationalities where
SMS national language shift table encoding is allowed/mandated (e.g. Turkey).
GsmAlphabet.countGsmSeptets() will try to find the most efficient encoding
among all combinations of enabled locking shift and single shift tables.
If no 7 bit encoding is possible, 16 bit UCS-2 encoding will be used.

This change also fixes a bug in the decoder: when an escape septet
is followed by a septet with no entry in the extension (single shift)
table, TS 23.038 Table 6.2.1.1 states that the MS shall display
the character in the main GSM 7 bit default alphabet table, or the
active national language locking shift table. Previously, we were
decoding this sequence as a space character. Two consecutive escape
septets will continue to decode as a space character, according to
Note 1 of table 6.2.1.1.

Change-Id: I4dab3f0ffe39f3df2064ed93c9c05f26e274d18b

2 files changed, 15 insertions, 34 deletions

diff --git a/telephony/java/android/telephony/SmsMessage.java b/telephony/java/android/telephony/SmsMessage.java
index a284ea5..34ca902 100644
--- a/telephony/java/android/telephony/SmsMessage.java
+++ b/telephony/java/android/telephony/SmsMessage.java
@@ -314,7 +314,8 @@ public class SmsMessage {
                     nextPos = pos + Math.min(limit, textLen - pos);
                 } else {
                     // For multi-segment messages, CDMA 7bit equals GSM 7bit encoding (EMS mode).
-                    nextPos = GsmAlphabet.findGsmSeptetLimitIndex(text, pos, limit);
+                    nextPos = GsmAlphabet.findGsmSeptetLimitIndex(text, pos, limit,
+                            ted.languageTable, ted.languageShiftTable);
                 }
             } else {  // Assume unicode.
                 nextPos = pos + Math.min(limit / 2, textLen - pos);
@@ -370,7 +371,8 @@ public class SmsMessage {
      */
 
     /**
-     * Get an SMS-SUBMIT PDU for a destination address and a message
+     * Get an SMS-SUBMIT PDU for a destination address and a message.
+     * This method will not attempt to use any GSM national language 7 bit encodings.
      *
      * @param scAddress Service Centre address.  Null means use default.
      * @return a <code>SubmitPdu</code> containing the encoded SC
@@ -397,7 +399,8 @@ public class SmsMessage {
     }
 
     /**
-     * Get an SMS-SUBMIT PDU for a destination address and a message
+     * Get an SMS-SUBMIT PDU for a destination address and a message.
+     * This method will not attempt to use any GSM national language 7 bit encodings.
      *
      * @param scAddress Service Centre address.  Null means use default.
      * @return a <code>SubmitPdu</code> containing the encoded SC
@@ -421,7 +424,8 @@ public class SmsMessage {
     }
 
     /**
-     * Get an SMS-SUBMIT PDU for a data message to a destination address &amp; port
+     * Get an SMS-SUBMIT PDU for a data message to a destination address &amp; port.
+     * This method will not attempt to use any GSM national language 7 bit encodings.
      *
      * @param scAddress Service Centre address. null == use default
      * @param destinationAddress the address of the destination for the message
diff --git a/telephony/java/android/telephony/gsm/SmsMessage.java b/telephony/java/android/telephony/gsm/SmsMessage.java
index 0c63c37..1b95cd4 100644
--- a/telephony/java/android/telephony/gsm/SmsMessage.java
+++ b/telephony/java/android/telephony/gsm/SmsMessage.java
@@ -297,37 +297,14 @@ public class SmsMessage {
      */
     @Deprecated
     public static int[] calculateLength(CharSequence messageBody, boolean use7bitOnly) {
+        SmsMessageBase.TextEncodingDetails ted =
+                com.android.internal.telephony.gsm.SmsMessage
+                        .calculateLength(messageBody, use7bitOnly);
         int ret[] = new int[4];
-
-        try {
-            // Try GSM alphabet
-            int septets = GsmAlphabet.countGsmSeptets(messageBody, !use7bitOnly);
-            ret[1] = septets;
-            if (septets > MAX_USER_DATA_SEPTETS) {
-                ret[0] = (septets + (MAX_USER_DATA_SEPTETS_WITH_HEADER - 1)) /
-                            MAX_USER_DATA_SEPTETS_WITH_HEADER;
-                ret[2] = (ret[0] * MAX_USER_DATA_SEPTETS_WITH_HEADER) - septets;
-            } else {
-                ret[0] = 1;
-                ret[2] = MAX_USER_DATA_SEPTETS - septets;
-            }
-            ret[3] = ENCODING_7BIT;
-        } catch (EncodeException ex) {
-            // fall back to UCS-2
-            int octets = messageBody.length() * 2;
-            ret[1] = messageBody.length();
-            if (octets > MAX_USER_DATA_BYTES) {
-                // 6 is the size of the user data header
-                ret[0] = (octets + (MAX_USER_DATA_BYTES_WITH_HEADER - 1)) /
-                            MAX_USER_DATA_BYTES_WITH_HEADER;
-                ret[2] = ((ret[0] * MAX_USER_DATA_BYTES_WITH_HEADER) - octets) / 2;
-            } else {
-                ret[0] = 1;
-                ret[2] = (MAX_USER_DATA_BYTES - octets)/2;
-            }
-            ret[3] = ENCODING_16BIT;
-        }
-
+        ret[0] = ted.msgCount;
+        ret[1] = ted.codeUnitCount;
+        ret[2] = ted.codeUnitsRemaining;
+        ret[3] = ted.codeUnitSize;
         return ret;
     }