Require length field for cyphalHeaderCRCAdd function. and fixes to formatting.

Author: hungatamazon

libudpard/udpard.c

@@ -190,7 +190,7 @@ typedef uint16_t CyphalHeaderCRC;
 #define CYPHAL_HEADER_CRC_INITIAL 0xFFFFU
 #define CYPHAL_HEADER_CRC_SIZE_BYTES 2U
 
-UDPARD_PRIVATE CyphalHeaderCRC CyphalHeaderCrcAddByte(const CyphalHeaderCRC crc, const uint8_t byte)
+UDPARD_PRIVATE CyphalHeaderCRC cyphalHeaderCrcAddByte(const CyphalHeaderCRC crc, const uint8_t byte)
 {
     // Based on CRC-16-CCITT-FALSE Function
     static const CyphalHeaderCRC Top  = 0x8000U;
@@ -205,17 +205,17 @@ UDPARD_PRIVATE CyphalHeaderCRC CyphalHeaderCrcAddByte(const CyphalHeaderCRC crc,
     out = (uint16_t) ((uint16_t) (out << 1U) ^ (((out & Top) != 0U) ? Poly : 0U));
     out = (uint16_t) ((uint16_t) (out << 1U) ^ (((out & Top) != 0U) ? Poly : 0U));
     out = (uint16_t) ((uint16_t) (out << 1U) ^ (((out & Top) != 0U) ? Poly : 0U));
-    return out;}
+    return out;
+}
 
-UDPARD_PRIVATE CyphalHeaderCRC CyphalHeaderCrcAdd(const CyphalHeaderCRC crc, const void* const header)
+UDPARD_PRIVATE CyphalHeaderCRC cyphalHeaderCrcAdd(const CyphalHeaderCRC crc, const size_t size, const void* const header)
 {
     UDPARD_ASSERT(header != NULL);
     CyphalHeaderCRC    out = crc;
     const uint8_t* p   = (const uint8_t*) header;
-    size_t cyphal_header_size_without_crc = sizeof(UdpardFrameHeader) - CYPHAL_HEADER_CRC_SIZE_BYTES;
-    for (size_t i = 0; i < cyphal_header_size_without_crc; i++)
+    for (size_t i = 0; i < size; i++)
     {
-        out = CyphalHeaderCrcAddByte(out, *p);
+        out = cyphalHeaderCrcAddByte(out, *p);
         ++p;
     }
     return out;
@@ -363,12 +363,13 @@ UDPARD_PRIVATE void txMakeFrameHeader(UdpardFrameHeader* const header,
 {
     UDPARD_ASSERT(frame_index <= UDPARD_MAX_FRAME_INDEX);
     uint32_t end_of_transfer_mask = (uint32_t) (end_of_transfer ? 1 : 0) << (uint32_t) UDPARD_END_OF_TRANSFER_OFFSET;
+    size_t cyphal_header_size_without_crc = sizeof(UdpardFrameHeader) - CYPHAL_HEADER_CRC_SIZE_BYTES;
     header->transfer_id           = transfer_id;
     header->priority              = (uint8_t) priority;
     header->frame_index_eot       = end_of_transfer_mask | frame_index;
     header->source_node_id        = src_node_id;
     header->destination_node_id   = dst_node_id;
-    header->cyphal_header_checksum = CyphalHeaderCrcAdd(CYPHAL_HEADER_CRC_INITIAL, header);
+    header->cyphal_header_checksum = cyphalHeaderCrcAdd(CYPHAL_HEADER_CRC_INITIAL, cyphal_header_size_without_crc, header);
     if (transfer_kind == UdpardTransferKindMessage)
     {
         header->data_specifier = (uint16_t) UPDARD_DATA_SPECIFIER_MESSAGE & port_id;  // SNM (0) + Subject ID

tests/exposed.hpp

@@ -79,7 +79,7 @@ extern "C" {
 
 auto crcAdd(const std::uint32_t crc, const std::size_t size, const void* const bytes) -> std::uint32_t;
 
-auto CyphalHeaderCrcAdd(const std::uint16_t crc, const void* const bytes) -> std::uint16_t;
+auto cyphalHeaderCrcAdd(const std::uint16_t crc, const std::size_t size, const void* const bytes) -> std::uint16_t;
 
 auto crcValue(const std::uint32_t crc) -> std::uint32_t;
 

tests/test_private_crc.cpp

@@ -24,10 +24,10 @@ TEST_CASE("TransferCRC")
 
 TEST_CASE("CyphalHeaderCRC")
 {
-    using exposed::CyphalHeaderCrcAdd;
+    using exposed::cyphalHeaderCrcAdd;
 
     std::uint16_t crc = 0xFFFFU;
     const uint8_t* header = reinterpret_cast<const uint8_t*>("\x01\x02\x03\x04\x05\x06\x07\x08\x09\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x20\x21\x22\x23\x24");
-    crc = CyphalHeaderCrcAdd(crc, header);
+    crc = cyphalHeaderCrcAdd(crc, 22, header);
     REQUIRE(0xB731 == crc);
 }