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Diffstat (limited to 'ext/mavlink/include/mavlink/mavlink_helpers.h')
| -rw-r--r-- | ext/mavlink/include/mavlink/mavlink_helpers.h | 579 |
1 files changed, 579 insertions, 0 deletions
diff --git a/ext/mavlink/include/mavlink/mavlink_helpers.h b/ext/mavlink/include/mavlink/mavlink_helpers.h new file mode 100644 index 0000000..daaf0e3 --- /dev/null +++ b/ext/mavlink/include/mavlink/mavlink_helpers.h @@ -0,0 +1,579 @@ +#ifndef _MAVLINK_HELPERS_H_ +#define _MAVLINK_HELPERS_H_ + +#include "string.h" +#include "checksum.h" +#include "mavlink_types.h" +#include "mavlink_conversions.h" + +#ifndef MAVLINK_HELPER +#define MAVLINK_HELPER +#endif + +/* + * Internal function to give access to the channel status for each channel + */ +#ifndef MAVLINK_GET_CHANNEL_STATUS +MAVLINK_HELPER mavlink_status_t* mavlink_get_channel_status(uint8_t chan) +{ +#ifdef MAVLINK_EXTERNAL_RX_STATUS + // No m_mavlink_status array defined in function, + // has to be defined externally +#else + static mavlink_status_t m_mavlink_status[MAVLINK_COMM_NUM_BUFFERS]; +#endif + return &m_mavlink_status[chan]; +} +#endif + +/* + * Internal function to give access to the channel buffer for each channel + */ +#ifndef MAVLINK_GET_CHANNEL_BUFFER +MAVLINK_HELPER mavlink_message_t* mavlink_get_channel_buffer(uint8_t chan) +{ + +#ifdef MAVLINK_EXTERNAL_RX_BUFFER + // No m_mavlink_buffer array defined in function, + // has to be defined externally +#else + static mavlink_message_t m_mavlink_buffer[MAVLINK_COMM_NUM_BUFFERS]; +#endif + return &m_mavlink_buffer[chan]; +} +#endif + +/** + * @brief Reset the status of a channel. + */ +MAVLINK_HELPER void mavlink_reset_channel_status(uint8_t chan) +{ + mavlink_status_t *status = mavlink_get_channel_status(chan); + status->parse_state = MAVLINK_PARSE_STATE_IDLE; +} + +/** + * @brief Finalize a MAVLink message with channel assignment + * + * This function calculates the checksum and sets length and aircraft id correctly. + * It assumes that the message id and the payload are already correctly set. This function + * can also be used if the message header has already been written before (as in mavlink_msg_xxx_pack + * instead of mavlink_msg_xxx_pack_headerless), it just introduces little extra overhead. + * + * @param msg Message to finalize + * @param system_id Id of the sending (this) system, 1-127 + * @param length Message length + */ +#if MAVLINK_CRC_EXTRA +MAVLINK_HELPER uint16_t mavlink_finalize_message_chan(mavlink_message_t* msg, uint8_t system_id, uint8_t component_id, + uint8_t chan, uint8_t length, uint8_t crc_extra) +#else +MAVLINK_HELPER uint16_t mavlink_finalize_message_chan(mavlink_message_t* msg, uint8_t system_id, uint8_t component_id, + uint8_t chan, uint8_t length) +#endif +{ + // This code part is the same for all messages; + msg->magic = MAVLINK_STX; + msg->len = length; + msg->sysid = system_id; + msg->compid = component_id; + // One sequence number per component + msg->seq = mavlink_get_channel_status(chan)->current_tx_seq; + mavlink_get_channel_status(chan)->current_tx_seq = mavlink_get_channel_status(chan)->current_tx_seq+1; + msg->checksum = crc_calculate(((const uint8_t*)(msg)) + 3, MAVLINK_CORE_HEADER_LEN); + crc_accumulate_buffer(&msg->checksum, _MAV_PAYLOAD(msg), msg->len); +#if MAVLINK_CRC_EXTRA + crc_accumulate(crc_extra, &msg->checksum); +#endif + mavlink_ck_a(msg) = (uint8_t)(msg->checksum & 0xFF); + mavlink_ck_b(msg) = (uint8_t)(msg->checksum >> 8); + + return length + MAVLINK_NUM_NON_PAYLOAD_BYTES; +} + + +/** + * @brief Finalize a MAVLink message with MAVLINK_COMM_0 as default channel + */ +#if MAVLINK_CRC_EXTRA +MAVLINK_HELPER uint16_t mavlink_finalize_message(mavlink_message_t* msg, uint8_t system_id, uint8_t component_id, + uint8_t length, uint8_t crc_extra) +{ + return mavlink_finalize_message_chan(msg, system_id, component_id, MAVLINK_COMM_0, length, crc_extra); +} +#else +MAVLINK_HELPER uint16_t mavlink_finalize_message(mavlink_message_t* msg, uint8_t system_id, uint8_t component_id, + uint8_t length) +{ + return mavlink_finalize_message_chan(msg, system_id, component_id, MAVLINK_COMM_0, length); +} +#endif + +#ifdef MAVLINK_USE_CONVENIENCE_FUNCTIONS +MAVLINK_HELPER void _mavlink_send_uart(mavlink_channel_t chan, const char *buf, uint16_t len); + +/** + * @brief Finalize a MAVLink message with channel assignment and send + */ +#if MAVLINK_CRC_EXTRA +MAVLINK_HELPER void _mav_finalize_message_chan_send(mavlink_channel_t chan, uint8_t msgid, const char *packet, + uint8_t length, uint8_t crc_extra) +#else +MAVLINK_HELPER void _mav_finalize_message_chan_send(mavlink_channel_t chan, uint8_t msgid, const char *packet, uint8_t length) +#endif +{ + uint16_t checksum; + uint8_t buf[MAVLINK_NUM_HEADER_BYTES]; + uint8_t ck[2]; + mavlink_status_t *status = mavlink_get_channel_status(chan); + buf[0] = MAVLINK_STX; + buf[1] = length; + buf[2] = status->current_tx_seq; + buf[3] = mavlink_system.sysid; + buf[4] = mavlink_system.compid; + buf[5] = msgid; + status->current_tx_seq++; + checksum = crc_calculate((const uint8_t*)&buf[1], MAVLINK_CORE_HEADER_LEN); + crc_accumulate_buffer(&checksum, packet, length); +#if MAVLINK_CRC_EXTRA + crc_accumulate(crc_extra, &checksum); +#endif + ck[0] = (uint8_t)(checksum & 0xFF); + ck[1] = (uint8_t)(checksum >> 8); + + MAVLINK_START_UART_SEND(chan, MAVLINK_NUM_NON_PAYLOAD_BYTES + (uint16_t)length); + _mavlink_send_uart(chan, (const char *)buf, MAVLINK_NUM_HEADER_BYTES); + _mavlink_send_uart(chan, packet, length); + _mavlink_send_uart(chan, (const char *)ck, 2); + MAVLINK_END_UART_SEND(chan, MAVLINK_NUM_NON_PAYLOAD_BYTES + (uint16_t)length); +} + +/** + * @brief re-send a message over a uart channel + * this is more stack efficient than re-marshalling the message + */ +MAVLINK_HELPER void _mavlink_resend_uart(mavlink_channel_t chan, const mavlink_message_t *msg) +{ + uint8_t ck[2]; + + ck[0] = (uint8_t)(msg->checksum & 0xFF); + ck[1] = (uint8_t)(msg->checksum >> 8); + // XXX use the right sequence here + + MAVLINK_START_UART_SEND(chan, MAVLINK_NUM_NON_PAYLOAD_BYTES + msg->len); + _mavlink_send_uart(chan, (const char *)&msg->magic, MAVLINK_NUM_HEADER_BYTES); + _mavlink_send_uart(chan, _MAV_PAYLOAD(msg), msg->len); + _mavlink_send_uart(chan, (const char *)ck, 2); + MAVLINK_END_UART_SEND(chan, MAVLINK_NUM_NON_PAYLOAD_BYTES + msg->len); +} +#endif // MAVLINK_USE_CONVENIENCE_FUNCTIONS + +/** + * @brief Pack a message to send it over a serial byte stream + */ +MAVLINK_HELPER uint16_t mavlink_msg_to_send_buffer(uint8_t *buffer, const mavlink_message_t *msg) +{ + memcpy(buffer, (const uint8_t *)&msg->magic, MAVLINK_NUM_HEADER_BYTES + (uint16_t)msg->len); + + uint8_t *ck = buffer + (MAVLINK_NUM_HEADER_BYTES + (uint16_t)msg->len); + + ck[0] = (uint8_t)(msg->checksum & 0xFF); + ck[1] = (uint8_t)(msg->checksum >> 8); + + return MAVLINK_NUM_NON_PAYLOAD_BYTES + (uint16_t)msg->len; +} + +union __mavlink_bitfield { + uint8_t uint8; + int8_t int8; + uint16_t uint16; + int16_t int16; + uint32_t uint32; + int32_t int32; +}; + + +MAVLINK_HELPER void mavlink_start_checksum(mavlink_message_t* msg) +{ + crc_init(&msg->checksum); +} + +MAVLINK_HELPER void mavlink_update_checksum(mavlink_message_t* msg, uint8_t c) +{ + crc_accumulate(c, &msg->checksum); +} + +/** + * This is a convenience function which handles the complete MAVLink parsing. + * the function will parse one byte at a time and return the complete packet once + * it could be successfully decoded. Checksum and other failures will be silently + * ignored. + * + * Messages are parsed into an internal buffer (one for each channel). When a complete + * message is received it is copies into *returnMsg and the channel's status is + * copied into *returnStats. + * + * @param chan ID of the current channel. This allows to parse different channels with this function. + * a channel is not a physical message channel like a serial port, but a logic partition of + * the communication streams in this case. COMM_NB is the limit for the number of channels + * on MCU (e.g. ARM7), while COMM_NB_HIGH is the limit for the number of channels in Linux/Windows + * @param c The char to parse + * + * @param returnMsg NULL if no message could be decoded, the message data else + * @param returnStats if a message was decoded, this is filled with the channel's stats + * @return 0 if no message could be decoded, 1 else + * + * A typical use scenario of this function call is: + * + * @code + * #include <inttypes.h> // For fixed-width uint8_t type + * + * mavlink_message_t msg; + * int chan = 0; + * + * + * while(serial.bytesAvailable > 0) + * { + * uint8_t byte = serial.getNextByte(); + * if (mavlink_parse_char(chan, byte, &msg)) + * { + * printf("Received message with ID %d, sequence: %d from component %d of system %d", msg.msgid, msg.seq, msg.compid, msg.sysid); + * } + * } + * + * + * @endcode + */ +MAVLINK_HELPER uint8_t mavlink_parse_char(uint8_t chan, uint8_t c, mavlink_message_t* r_message, mavlink_status_t* r_mavlink_status) +{ + /* + default message crc function. You can override this per-system to + put this data in a different memory segment + */ +#if MAVLINK_CRC_EXTRA +#ifndef MAVLINK_MESSAGE_CRC + static const uint8_t mavlink_message_crcs[256] = MAVLINK_MESSAGE_CRCS; +#define MAVLINK_MESSAGE_CRC(msgid) mavlink_message_crcs[msgid] +#endif +#endif + +/* Enable this option to check the length of each message. + This allows invalid messages to be caught much sooner. Use if the transmission + medium is prone to missing (or extra) characters (e.g. a radio that fades in + and out). Only use if the channel will only contain messages types listed in + the headers. +*/ +#ifdef MAVLINK_CHECK_MESSAGE_LENGTH +#ifndef MAVLINK_MESSAGE_LENGTH + static const uint8_t mavlink_message_lengths[256] = MAVLINK_MESSAGE_LENGTHS; +#define MAVLINK_MESSAGE_LENGTH(msgid) mavlink_message_lengths[msgid] +#endif +#endif + + mavlink_message_t* rxmsg = mavlink_get_channel_buffer(chan); ///< The currently decoded message + mavlink_status_t* status = mavlink_get_channel_status(chan); ///< The current decode status + int bufferIndex = 0; + + status->msg_received = 0; + + switch (status->parse_state) + { + case MAVLINK_PARSE_STATE_UNINIT: + case MAVLINK_PARSE_STATE_IDLE: + if (c == MAVLINK_STX) + { + status->parse_state = MAVLINK_PARSE_STATE_GOT_STX; + rxmsg->len = 0; + rxmsg->magic = c; + mavlink_start_checksum(rxmsg); + } + break; + + case MAVLINK_PARSE_STATE_GOT_STX: + if (status->msg_received +/* Support shorter buffers than the + default maximum packet size */ +#if (MAVLINK_MAX_PAYLOAD_LEN < 255) + || c > MAVLINK_MAX_PAYLOAD_LEN +#endif + ) + { + status->buffer_overrun++; + status->parse_error++; + status->msg_received = 0; + status->parse_state = MAVLINK_PARSE_STATE_IDLE; + } + else + { + // NOT counting STX, LENGTH, SEQ, SYSID, COMPID, MSGID, CRC1 and CRC2 + rxmsg->len = c; + status->packet_idx = 0; + mavlink_update_checksum(rxmsg, c); + status->parse_state = MAVLINK_PARSE_STATE_GOT_LENGTH; + } + break; + + case MAVLINK_PARSE_STATE_GOT_LENGTH: + rxmsg->seq = c; + mavlink_update_checksum(rxmsg, c); + status->parse_state = MAVLINK_PARSE_STATE_GOT_SEQ; + break; + + case MAVLINK_PARSE_STATE_GOT_SEQ: + rxmsg->sysid = c; + mavlink_update_checksum(rxmsg, c); + status->parse_state = MAVLINK_PARSE_STATE_GOT_SYSID; + break; + + case MAVLINK_PARSE_STATE_GOT_SYSID: + rxmsg->compid = c; + mavlink_update_checksum(rxmsg, c); + status->parse_state = MAVLINK_PARSE_STATE_GOT_COMPID; + break; + + case MAVLINK_PARSE_STATE_GOT_COMPID: +#ifdef MAVLINK_CHECK_MESSAGE_LENGTH + if (rxmsg->len != MAVLINK_MESSAGE_LENGTH(c)) + { + status->parse_error++; + status->parse_state = MAVLINK_PARSE_STATE_IDLE; + break; + if (c == MAVLINK_STX) + { + status->parse_state = MAVLINK_PARSE_STATE_GOT_STX; + mavlink_start_checksum(rxmsg); + } + } +#endif + rxmsg->msgid = c; + mavlink_update_checksum(rxmsg, c); + if (rxmsg->len == 0) + { + status->parse_state = MAVLINK_PARSE_STATE_GOT_PAYLOAD; + } + else + { + status->parse_state = MAVLINK_PARSE_STATE_GOT_MSGID; + } + break; + + case MAVLINK_PARSE_STATE_GOT_MSGID: + _MAV_PAYLOAD_NON_CONST(rxmsg)[status->packet_idx++] = (char)c; + mavlink_update_checksum(rxmsg, c); + if (status->packet_idx == rxmsg->len) + { + status->parse_state = MAVLINK_PARSE_STATE_GOT_PAYLOAD; + } + break; + + case MAVLINK_PARSE_STATE_GOT_PAYLOAD: +#if MAVLINK_CRC_EXTRA + mavlink_update_checksum(rxmsg, MAVLINK_MESSAGE_CRC(rxmsg->msgid)); +#endif + if (c != (rxmsg->checksum & 0xFF)) { + // Check first checksum byte + status->parse_error++; + status->msg_received = 0; + status->parse_state = MAVLINK_PARSE_STATE_IDLE; + if (c == MAVLINK_STX) + { + status->parse_state = MAVLINK_PARSE_STATE_GOT_STX; + rxmsg->len = 0; + mavlink_start_checksum(rxmsg); + } + } + else + { + status->parse_state = MAVLINK_PARSE_STATE_GOT_CRC1; + _MAV_PAYLOAD_NON_CONST(rxmsg)[status->packet_idx] = (char)c; + } + break; + + case MAVLINK_PARSE_STATE_GOT_CRC1: + if (c != (rxmsg->checksum >> 8)) { + // Check second checksum byte + status->parse_error++; + status->msg_received = 0; + status->parse_state = MAVLINK_PARSE_STATE_IDLE; + if (c == MAVLINK_STX) + { + status->parse_state = MAVLINK_PARSE_STATE_GOT_STX; + rxmsg->len = 0; + mavlink_start_checksum(rxmsg); + } + } + else + { + // Successfully got message + status->msg_received = 1; + status->parse_state = MAVLINK_PARSE_STATE_IDLE; + _MAV_PAYLOAD_NON_CONST(rxmsg)[status->packet_idx+1] = (char)c; + memcpy(r_message, rxmsg, sizeof(mavlink_message_t)); + } + break; + } + + bufferIndex++; + // If a message has been sucessfully decoded, check index + if (status->msg_received == 1) + { + //while(status->current_seq != rxmsg->seq) + //{ + // status->packet_rx_drop_count++; + // status->current_seq++; + //} + status->current_rx_seq = rxmsg->seq; + // Initial condition: If no packet has been received so far, drop count is undefined + if (status->packet_rx_success_count == 0) status->packet_rx_drop_count = 0; + // Count this packet as received + status->packet_rx_success_count++; + } + + r_mavlink_status->current_rx_seq = status->current_rx_seq+1; + r_mavlink_status->packet_rx_success_count = status->packet_rx_success_count; + r_mavlink_status->packet_rx_drop_count = status->parse_error; + status->parse_error = 0; + return status->msg_received; +} + +/** + * @brief Put a bitfield of length 1-32 bit into the buffer + * + * @param b the value to add, will be encoded in the bitfield + * @param bits number of bits to use to encode b, e.g. 1 for boolean, 2, 3, etc. + * @param packet_index the position in the packet (the index of the first byte to use) + * @param bit_index the position in the byte (the index of the first bit to use) + * @param buffer packet buffer to write into + * @return new position of the last used byte in the buffer + */ +MAVLINK_HELPER uint8_t put_bitfield_n_by_index(int32_t b, uint8_t bits, uint8_t packet_index, uint8_t bit_index, uint8_t* r_bit_index, uint8_t* buffer) +{ + uint16_t bits_remain = bits; + // Transform number into network order + int32_t v; + uint8_t i_bit_index, i_byte_index, curr_bits_n; +#if MAVLINK_NEED_BYTE_SWAP + union { + int32_t i; + uint8_t b[4]; + } bin, bout; + bin.i = b; + bout.b[0] = bin.b[3]; + bout.b[1] = bin.b[2]; + bout.b[2] = bin.b[1]; + bout.b[3] = bin.b[0]; + v = bout.i; +#else + v = b; +#endif + + // buffer in + // 01100000 01000000 00000000 11110001 + // buffer out + // 11110001 00000000 01000000 01100000 + + // Existing partly filled byte (four free slots) + // 0111xxxx + + // Mask n free bits + // 00001111 = 2^0 + 2^1 + 2^2 + 2^3 = 2^n - 1 + // = ((uint32_t)(1 << n)) - 1; // = 2^n - 1 + + // Shift n bits into the right position + // out = in >> n; + + // Mask and shift bytes + i_bit_index = bit_index; + i_byte_index = packet_index; + if (bit_index > 0) + { + // If bits were available at start, they were available + // in the byte before the current index + i_byte_index--; + } + + // While bits have not been packed yet + while (bits_remain > 0) + { + // Bits still have to be packed + // there can be more than 8 bits, so + // we might have to pack them into more than one byte + + // First pack everything we can into the current 'open' byte + //curr_bits_n = bits_remain << 3; // Equals bits_remain mod 8 + //FIXME + if (bits_remain <= (uint8_t)(8 - i_bit_index)) + { + // Enough space + curr_bits_n = (uint8_t)bits_remain; + } + else + { + curr_bits_n = (8 - i_bit_index); + } + + // Pack these n bits into the current byte + // Mask out whatever was at that position with ones (xxx11111) + buffer[i_byte_index] &= (0xFF >> (8 - curr_bits_n)); + // Put content to this position, by masking out the non-used part + buffer[i_byte_index] |= ((0x00 << curr_bits_n) & v); + + // Increment the bit index + i_bit_index += curr_bits_n; + + // Now proceed to the next byte, if necessary + bits_remain -= curr_bits_n; + if (bits_remain > 0) + { + // Offer another 8 bits / one byte + i_byte_index++; + i_bit_index = 0; + } + } + + *r_bit_index = i_bit_index; + // If a partly filled byte is present, mark this as consumed + if (i_bit_index != 7) i_byte_index++; + return i_byte_index - packet_index; +} + +#ifdef MAVLINK_USE_CONVENIENCE_FUNCTIONS + +// To make MAVLink work on your MCU, define comm_send_ch() if you wish +// to send 1 byte at a time, or MAVLINK_SEND_UART_BYTES() to send a +// whole packet at a time + +/* + +#include "mavlink_types.h" + +void comm_send_ch(mavlink_channel_t chan, uint8_t ch) +{ + if (chan == MAVLINK_COMM_0) + { + uart0_transmit(ch); + } + if (chan == MAVLINK_COMM_1) + { + uart1_transmit(ch); + } +} + */ + +MAVLINK_HELPER void _mavlink_send_uart(mavlink_channel_t chan, const char *buf, uint16_t len) +{ +#ifdef MAVLINK_SEND_UART_BYTES + /* this is the more efficient approach, if the platform + defines it */ + MAVLINK_SEND_UART_BYTES(chan, (const uint8_t *)buf, len); +#else + /* fallback to one byte at a time */ + uint16_t i; + for (i = 0; i < len; i++) { + comm_send_ch(chan, (uint8_t)buf[i]); + } +#endif +} +#endif // MAVLINK_USE_CONVENIENCE_FUNCTIONS + +#endif /* _MAVLINK_HELPERS_H_ */ |