table code types containing static arrays

Static arrays have a 2-entry header (8 bytes), plus the entries
describing the contents of the array.

Array contents cannot consist of more than 256 entries (including header
entries and entries describing nested types). The array length cannot
exceed 65535.

Author: tpwrules

canard.c

@@ -1923,6 +1923,23 @@ CANARD_INTERNAL bool tableDecodeCore(const CanardCodingTableEntry* entry,
             *bit_ofs += bitlen;
             break;
 
+        case CANARD_TABLE_CODING_ARRAY_STATIC: {
+            const CanardCodingTableEntry* aux = ++entry;
+            const CanardCodingTableEntry* array_entry = ++entry;
+            const CanardCodingTableEntry* array_entry_last = array_entry + bitlen;
+            entry = array_entry_last; // point entry to last for ++entry at end of loop
+
+            uint16_t elems = aux->type | ((uint16_t)aux->bitlen << 8);
+            while (elems--) {
+                if (tableDecodeCore(array_entry, array_entry_last, transfer, bit_ofs, p)) {
+                    return true;
+                }
+                p = (char*)p + aux->offset;
+            }
+
+            break;
+        }
+
         default:
             return true; // invalid type
         }
@@ -1964,6 +1981,21 @@ CANARD_INTERNAL void tableEncodeCore(const CanardCodingTableEntry* entry,
             *bit_ofs += bitlen;
             break;
 
+        case CANARD_TABLE_CODING_ARRAY_STATIC: {
+            const CanardCodingTableEntry* aux = ++entry;
+            const CanardCodingTableEntry* array_entry = ++entry;
+            const CanardCodingTableEntry* array_entry_last = array_entry + bitlen;
+            entry = array_entry_last; // point entry to last for ++entry at end of loop
+
+            uint16_t elems = aux->type | ((uint16_t)aux->bitlen << 8);
+            while (elems--) {
+                tableEncodeCore(array_entry, array_entry_last, buffer, bit_ofs, p);
+                p = (const char*)p + aux->offset;
+            }
+
+            break;
+        }
+
         default:
             return; // invalid type
         }

canard.h

@@ -469,6 +469,7 @@ struct CanardRxTransfer
 #define CANARD_TABLE_CODING_SIGNED (1)
 #define CANARD_TABLE_CODING_FLOAT (2)
 #define CANARD_TABLE_CODING_VOID (3)
+#define CANARD_TABLE_CODING_ARRAY_STATIC (4)
 
 /**
  * This structure describes the encoded form of part of a particular message. It
@@ -500,6 +501,24 @@ typedef struct {
 #define CANARD_TABLE_CODING_ENTRY_VOID(bitlen) \
     {0, CANARD_TABLE_CODING_VOID, bitlen}
 
+/**
+ * Coding table entries (2 total) for array type with a static length.
+ *
+ * first entry:
+ *  offset: offset, in chars, to the storage of the first element in the message struct
+ *  type: 4 for static array
+ *  bitlen: total number of entries after these which describe the array contents (may encompass e.g. other arrays), minus one
+ * second entry:
+ *  offset: size, in chars, of one array element, i.e. sizeof(arr[0])
+ *  type: low 8 bits of array length
+ *  bitlen: high 8 bits of array length
+ *
+ * note: entries which describe the array contents have offsets relative to the start of the array storage
+ */
+#define CANARD_TABLE_CODING_ENTRIES_ARRAY_STATIC(offset, num_entries, elem_size, array_len) \
+    {offset, CANARD_TABLE_CODING_ARRAY_STATIC, (num_entries)-1}, \
+    {elem_size, (array_len)&0xFF, (array_len)>>8}
+
 /**
  * This structure describes the encoded form of a particular message. It can be
  * contained in ROM. It should be generated using dronecan_dsdlc.