From 0ffb123701c2e6124d7c735cdb55c250564d12c6 Mon Sep 17 00:00:00 2001 From: Kynos Date: Mon, 16 Jun 2014 15:35:38 +0200 Subject: Store hash instead of full strings for SW & HW version --- src/drivers/gps/ubx.cpp | 48 +++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 39 insertions(+), 9 deletions(-) (limited to 'src/drivers/gps/ubx.cpp') diff --git a/src/drivers/gps/ubx.cpp b/src/drivers/gps/ubx.cpp index be19ce488..adc7130dd 100644 --- a/src/drivers/gps/ubx.cpp +++ b/src/drivers/gps/ubx.cpp @@ -72,6 +72,10 @@ #define MIN(X,Y) ((X) < (Y) ? (X) : (Y)) #define SWAP16(X) ((((X) >> 8) & 0x00ff) | (((X) << 8) & 0xff00)) +#define FNV1_32_INIT ((uint32_t)0x811c9dc5) // init value for FNV1 hash algorithm +#define FNV1_32_PRIME ((uint32_t)0x01000193) // magic prime for FNV1 hash algorithm + + /**** Trace macros, disable for production builds */ #define UBX_TRACE_PARSER(s, ...) {/*printf(s, ## __VA_ARGS__);*/} /* decoding progress in parse_char() */ #define UBX_TRACE_RXMSG(s, ...) {/*printf(s, ## __VA_ARGS__);*/} /* Rx msgs in payload_rx_done() */ @@ -90,11 +94,10 @@ UBX::UBX(const int &fd, struct vehicle_gps_position_s *gps_position, struct sate _got_posllh(false), _got_velned(false), _disable_cmd_last(0), - _ack_waiting_msg(0) + _ack_waiting_msg(0), + _ubx_version(0) { decode_init(); - memset(_ubx_sw_version, 0, sizeof(_ubx_sw_version)); - memset(_ubx_hw_version, 0, sizeof(_ubx_hw_version)); } UBX::~UBX() @@ -633,18 +636,19 @@ UBX::payload_rx_add_mon_ver(const uint8_t b) _buf.raw[_rx_payload_index] = b; } else { if (_rx_payload_index == sizeof(ubx_payload_rx_mon_ver_part1_t)) { - // Part 1 complete: decode Part 1 buffer - strncpy(_ubx_sw_version, (char*)_buf.payload_rx_mon_ver_part1.swVersion, sizeof(_ubx_sw_version)); - strncpy(_ubx_hw_version, (char*)_buf.payload_rx_mon_ver_part1.hwVersion, sizeof(_ubx_hw_version)); - UBX_WARN("VER sw %30s", _ubx_sw_version); - UBX_WARN("VER hw %10s", _ubx_hw_version); + // Part 1 complete: decode Part 1 buffer and calculate hash for SW&HW version strings + _ubx_version = fnv1_32_str(_buf.payload_rx_mon_ver_part1.swVersion, FNV1_32_INIT); + _ubx_version = fnv1_32_str(_buf.payload_rx_mon_ver_part1.hwVersion, _ubx_version); + UBX_WARN("VER hash 0x%08x", _ubx_version); + UBX_WARN("VER hw \"%10s\"", _buf.payload_rx_mon_ver_part1.hwVersion); + UBX_WARN("VER sw \"%30s\"", _buf.payload_rx_mon_ver_part1.swVersion); } // fill Part 2 buffer unsigned buf_index = (_rx_payload_index - sizeof(ubx_payload_rx_mon_ver_part1_t)) % sizeof(ubx_payload_rx_mon_ver_part2_t); _buf.raw[buf_index] = b; if (buf_index == sizeof(ubx_payload_rx_mon_ver_part2_t) - 1) { // Part 2 complete: decode Part 2 buffer - UBX_WARN("VER ext %30s", _buf.payload_rx_mon_ver_part2.extension); + UBX_WARN("VER ext \" %30s\"", _buf.payload_rx_mon_ver_part2.extension); } } @@ -877,3 +881,29 @@ UBX::send_message(const uint16_t msg, const uint8_t *payload, const uint16_t len write(_fd, (const void *)payload, length); write(_fd, (const void *)&checksum, sizeof(checksum)); } + +uint32_t +UBX::fnv1_32_str(uint8_t *str, uint32_t hval) +{ + uint8_t *s = str; + + /* + * FNV-1 hash each octet in the buffer + */ + while (*s) { + + /* multiply by the 32 bit FNV magic prime mod 2^32 */ +#if defined(NO_FNV_GCC_OPTIMIZATION) + hval *= FNV1_32_PRIME; +#else + hval += (hval<<1) + (hval<<4) + (hval<<7) + (hval<<8) + (hval<<24); +#endif + + /* xor the bottom with the current octet */ + hval ^= (uint32_t)*s++; + } + + /* return our new hash value */ + return hval; +} + -- cgit v1.2.3