int aws_iot_st_msg_deserialize_from_cursor()

in source/serializer.c [164:222]

• 55 lines of code
• 18 McCabe index (conditional complexity)

int aws_iot_st_msg_deserialize_from_cursor(
    struct aws_iot_st_msg *message,
    struct aws_byte_cursor *cursor,
    struct aws_allocator *allocator) {
    AWS_RETURN_ERROR_IF2(cursor->len < AWS_IOT_ST_MAX_MESSAGE_SIZE, AWS_ERROR_INVALID_BUFFER_SIZE);
    uint8_t wire_type;
    uint8_t field_number;
    int length;
    int payload_check = 0;
    while ((aws_byte_cursor_is_valid(cursor)) && (cursor->len > 0)) {
        // wire_type is only the first 3 bits, Zeroing out the first 5
        // 0x07 == 00000111
        wire_type = *cursor->ptr & 0x07;
        field_number = (*cursor->ptr) >> 3;
        aws_byte_cursor_advance(cursor, 1);

        if (field_number == AWS_IOT_ST_STREAM_ID_FIELD_NUMBER && wire_type == AWS_IOT_ST_VARINT_WIRE) {
            uint32_t res = 0;
            if (s_iot_st_decode_varint_uint32_t(cursor, &res) != AWS_OP_SUCCESS) {
                return AWS_OP_ERR;
            }
            message->stream_id = res;
        } else if (field_number == AWS_IOT_ST_IGNORABLE_FIELD_NUMBER && wire_type == AWS_IOT_ST_VARINT_WIRE) {
            uint32_t res = 0;
            if (s_iot_st_decode_varint_uint32_t(cursor, &res) != AWS_OP_SUCCESS) {
                return AWS_OP_ERR;
            }
            message->ignorable = res;
        } else if (field_number == AWS_IOT_ST_TYPE_FIELD_NUMBER && wire_type == AWS_IOT_ST_VARINT_WIRE) {
            uint32_t res = 0;
            if (s_iot_st_decode_varint_uint32_t(cursor, &res) != AWS_OP_SUCCESS) {
                return AWS_OP_ERR;
            }
            message->type = res;
        } else if (field_number == AWS_IOT_ST_PAYLOAD_FIELD_NUMBER && wire_type == AWS_IOT_ST_VARINT_LENGTHDELIM_WIRE) {
            uint32_t res = 0;
            if (s_iot_st_decode_varint_uint32_t(cursor, &res) != AWS_OP_SUCCESS) {
                return AWS_OP_ERR;
            }
            length = res;
            if (aws_byte_buf_init(&message->payload, allocator, length) != AWS_OP_SUCCESS) {
                return AWS_OP_ERR;
            }

            if (s_aws_st_decode_lengthdelim(cursor, &message->payload, length) != AWS_OP_SUCCESS) {
                goto cleanup;
            }
            aws_byte_cursor_advance(cursor, length);
            payload_check = 1;
        }
    }
    if (payload_check == 0) {
        AWS_ZERO_STRUCT(message->payload);
    }
    return AWS_OP_SUCCESS;
cleanup:
    aws_byte_buf_clean_up(&message->payload);
    return AWS_OP_ERR;
}