feat: implement IRA->GSM character set encoding & decoding0.0.10

This adds support for certain characters like @ $ ~ ^

1 files changed, 45 insertions, 0 deletions

diff --git a/src/pdu_encode.c b/src/pdu_encode.c
index 1bb7e4d..f0d8c96 100644
--- a/src/pdu_encode.c
+++ b/src/pdu_encode.c
@@ -182,6 +182,51 @@ int pdu_encode_user_data(char *pdu_str, size_t len, struct pdu_info *pdu, int *n
 		return -1;
 	}
 
+
+  //Convert to GSM character set, Only for 7-bit character sets
+	if ((pdu->data_coding.general.alphabet == PDU_ALPHABET_DEFAULT) ||
+      (pdu->data_coding.general.alphabet == PDU_ALPHABET_CDMA_DEFAULT)) {
+    int read = 0;
+    int store = 0;
+    char initial_user_data[PDU_UD_7BIT_MAX];
+
+    for (read = 0; read < pdu->user_data_len; read++) {
+      initial_user_data[read] = pdu->user_data[read];
+    }
+    initial_user_data[read] = 0;
+
+    log_debug("Converting from IRA character set to GSM");
+    for (read = 0; read < pdu->user_data_len; read++) {
+      int GSMchar = indexOfChar(strGSMTable, GSM_TABLE_SIZE, initial_user_data[read]);
+
+      if (GSMchar >= 0) {
+        log_debug("IRA before: 0x%02X | GSM after:   0x%02X", initial_user_data[read], GSMchar);
+        pdu->user_data[store] = GSMchar;
+      }
+      else {
+        //Check in extended table
+        GSMchar = indexOfChar(strExtendedTable, GSM_TABLE_SIZE, initial_user_data[read]);
+
+        if (GSMchar >= 0) {
+          log_debug("IRA before: 0x%02X | GSM after: 0x1B%02X", initial_user_data[read], GSMchar);
+          pdu->user_data[store] = 0x1B;
+          store++;
+          pdu->user_data[store] = GSMchar;
+        }
+        else {
+          log_debug("IRA before: 0x%02X | Translation not found - no change", initial_user_data[read]);
+          pdu->user_data[store] = initial_user_data[read];
+        }
+      }
+
+      store++;
+    }
+
+    //Update lengths
+    pdu->user_data_len += store - read;
+  }
+
+
 	if (pdu->data_coding.general.alphabet == PDU_ALPHABET_DEFAULT) {
 		if (pdu->user_data_len > PDU_UD_7BIT_MAX) {
 			log_error("string exceeds 7-bit data max length");