Mirror
/
ardupilot
mirror of https://github.com/ArduPilot/ardupilot
5
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

AP_Param: added some comments on AP_Vector3f handling

This commit is contained in:
Andrew Tridgell 2012-02-25 11:37:15 +11:00
parent 3cf0eebac8
commit 051bd78b37
1 changed files with 15 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
libraries/AP_Common/AP_Param.cpp
View File

@ -41,8 +41,17 @@
// elements.
#define GROUP_ID(grpinfo, base, i, shift) ((base)+(((uint16_t)PGM_UINT8(&grpinfo[i].idx))<<(shift)))
// Note about AP_Vector3f handling.
// The code has special cases for AP_Vector3f to allow it to be viewed
// as both a single 3 element vector and as a set of 3 AP_Float
// variables. This is done to make it possible for MAVLink to see
// vectors as parameters, which allows users to save their compass
// offsets in MAVLink parameter files. The code involves quite a few
// special cases which could be generalised to any vector/matrix type
// if we end up needing this behaviour for other than AP_Vector3f
// Static member variables for AP_Param.
// static member variables for AP_Param.
//
// max EEPROM write size. This is usually less than the physical
@ -315,7 +324,8 @@ const struct AP_Param::Info *AP_Param::find_var_info_group(const struct GroupInf
} else if (type == AP_PARAM_VECTOR3F &&
(base+ofs+sizeof(float) == (uintptr_t)this ||
base+ofs+2*sizeof(float) == (uintptr_t)this)) {
// we are inside a Vector3f
// we are inside a Vector3f. We need to work out which
// element of the vector the current object refers to.
*idx = (((uintptr_t)this) - (base+ofs))/sizeof(float);
*group_element = GROUP_ID(group_info, group_base, i, group_shift);
*group_ret = &group_info[i];
@ -348,7 +358,8 @@ const struct AP_Param::Info *AP_Param::find_var_info(uint8_t *group_element,
} else if (type == AP_PARAM_VECTOR3F &&
(base+sizeof(float) == (uintptr_t)this ||
base+2*sizeof(float) == (uintptr_t)this)) {
// we are inside a Vector3f
// we are inside a Vector3f. Work out which element we are
// referring to.
*idx = (((uintptr_t)this) - base)/sizeof(float);
*group_element = 0;
*group_ret = NULL;
@ -422,6 +433,7 @@ void AP_Param::add_vector3f_suffix(char *buffer, size_t buffer_size, uint8_t idx
{
uint8_t len = strnlen(buffer, buffer_size);
if ((size_t)(len+3) >= buffer_size) {
// the suffix doesn't fit
return;
}
buffer[len] = '_';