[hamradio-commits] [dump1090] 107/389: VK1ET : Decode mode ASCII hex input message types

[Matthew Ernisse]

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mernisse-guest pushed a commit to branch master
in repository dump1090.

commit 3dbc0efffc98ea71dc08487e73a15d38661fbcc9
Author: Malcolm Robb <Support at ATTAvionics.com>
Date:   Wed Apr 24 20:46:59 2013 +0100

    VK1ET : Decode mode ASCII hex input message types
    
    Modifications entirely base on code supplied by John VK1ET.
    
    Supports additional AVR raw ASCII input message stream types
---
 dump1090.c | 65 ++++++++++++++++++++++++++++++++++++++++++--------------------
 1 file changed, 44 insertions(+), 21 deletions(-)

diff --git a/dump1090.c b/dump1090.c
index f25d1e2..07b122a 100644
--- a/dump1090.c
+++ b/dump1090.c
@@ -2962,40 +2962,63 @@ int decodeHexMessage(struct client *c) {
     unsigned char msg[MODES_LONG_MSG_BYTES];
     struct modesMessage mm;
 
-    /* Remove spaces on the left and on the right. */
+    // Always mark the timestamp as invalid for packets received over the internet
+    // Mixing of data from two or more different receivers and publishing
+    // as coming from one would lead to corrupt mlat data
+    // Non timemarked internet data has indeterminate delay
+    mm.timestampMsg = -1;
+    mm.signalLevel  = -1;
+
+    // Remove spaces on the left and on the right
     while(l && isspace(hex[l-1])) {
-        hex[l-1] = '\0';
-        l--;
+        hex[l-1] = '\0'; l--;
     }
     while(isspace(*hex)) {
-        hex++;
-        l--;
+        hex++; l--;
     }
 
-    /* Turn the message into binary. */
-    if (l < 2 || (hex[0] != '*' && hex[0] != '@') || hex[l-1] != ';') return 0;
-    if (hex[0] == '@') {
-        hex += 13; l -= 15; // Skip @, and timestamp, and ;
-    } else {
-        hex++; l-=2; // Skip * and ;
+    // Turn the message into binary.
+    // Accept *-AVR raw @-AVR/BEAST timeS+raw %-AVR timeS+raw (CRC good) <-BEAST timeS+sigL+raw
+    // and some AVR recorer that we can understand
+    if (hex[l-1] != ';') {return (0);} // not complete - abort
+
+    switch(hex[0]) {
+        case '<': {
+            mm.signalLevel = (hexDigitVal(hex[13])<<4) | hexDigitVal(hex[14]);
+            hex += 15; l -= 16; // Skip <, timestamp and siglevel, and ;
+            break;}
+
+        case '@':
+        case '%':
+        case '#':
+        case '$': {
+            hex += 13; l -= 14; // Skip @,%,#,$, and timestamp, and ;
+            break;}
+
+        case '*':
+        case ':': {
+            hex++; l-=2; // Skip * and ;
+            break;}
+
+        default: {
+            return (0); // We don't know what this is, so abort
+            break;}
     }
-    if (l > MODES_LONG_MSG_BYTES*2) return 0; /* Too long message... broken. */
+
+    if ( (l < 4) || (l > MODES_LONG_MSG_BYTES*2) ) return (0); // Too short or long message... broken
     for (j = 0; j < l; j += 2) {
         int high = hexDigitVal(hex[j]);
-        int low = hexDigitVal(hex[j+1]);
+        int low  = hexDigitVal(hex[j+1]);
 
         if (high == -1 || low == -1) return 0;
         msg[j/2] = (high<<4) | low;
     }
-    // Always mark the timestamp as invalid for packets received over the internet
-    // Mixing of data from two or more different receivers and publishing
-    // as coming from one would lead to corrupt mlat data
-    // Non timemarked internet data has indeterminate delay
-    mm.timestampMsg = -1;
-    mm.signalLevel  = -1;
-    decodeModesMessage(&mm,msg);
+
+    if (l < 5) {decodeModeAMessage((uint)((msg[0]<<8) + msg[1]), &mm);} // ModeA or ModeC
+    else       {decodeModesMessage(&mm, msg);}
+
     useModesMessage(&mm);
-    return 0;
+    return (0);
 }
 
 /* Return a description of planes in json. */

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