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AP_Mount: viewpro calc_crc len arg fix 

Also remove one unnecessary length check
Also correct length check that meant last byte of buffer was unusable
This commit is contained in:
Randy Mackay 2023-07-18 11:09:04 +09:00
parent e0353666d4
commit d5977b6d96
2 changed files with 4 additions and 9 deletions
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11
libraries/AP_Mount/AP_Mount_Viewpro.cpp
View File

@ -191,7 +191,7 @@ void AP_Mount_Viewpro::read_incoming_packets()
_msg_buff[_msg_buff_len++] = b;
// protect against overly long messages
if (_msg_buff_len >= AP_MOUNT_VIEWPRO_PACKETLEN_MAX) {
if (_msg_buff_len > AP_MOUNT_VIEWPRO_PACKETLEN_MAX) {
reset_parser = true;
debug("vp buff full s:%u len:%u", (unsigned)_parsed_msg.state, (unsigned)_msg_buff_len);
}
@ -233,12 +233,7 @@ void AP_Mount_Viewpro::read_incoming_packets()
// length held in bits 0 ~ 5. length includes this length byte, frame id and final crc
// ignore frame counter held in bits 6~7
_parsed_msg.data_len = b & 0x3F;
if (_parsed_msg.data_len <= AP_MOUNT_VIEWPRO_DATALEN_MAX) {
_parsed_msg.state = ParseState::WAITING_FOR_FRAMEID;
} else {
reset_parser = true;
debug("data len too long:%u (>%u)", (unsigned)_parsed_msg.data_len, (unsigned)AP_MOUNT_VIEWPRO_DATALEN_MAX);
}
_parsed_msg.state = ParseState::WAITING_FOR_FRAMEID;
break;
case ParseState::WAITING_FOR_FRAMEID:
@ -327,7 +322,7 @@ void AP_Mount_Viewpro::process_packet()
}
// calculate crc of the received message
uint8_t AP_Mount_Viewpro::calc_crc(const uint8_t *buf, uint32_t len) const
uint8_t AP_Mount_Viewpro::calc_crc(const uint8_t *buf, uint8_t len) const
{
uint8_t res = 0;
for (uint8_t i=0; i<len; i++) {

2
libraries/AP_Mount/AP_Mount_Viewpro.h
View File

@ -281,7 +281,7 @@ private:
void process_packet();
// calculate crc of the received message
uint8_t calc_crc(const uint8_t *buf, uint32_t length) const;
uint8_t calc_crc(const uint8_t *buf, uint8_t length) const;
// get the length and frame count byte (3rd byte of all messages)
// length is all bytes after the header including CRC