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ardupilot/libraries/AP_Common/AP_Var.cpp

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#if 0 // we can't build this and AP_Param due to AP_Common.h conflicts
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
//
// This is free software; you can redistribute it and/or modify it under
// the terms of the GNU Lesser General Public License as published by the
// Free Software Foundation; either version 2.1 of the License, or (at
// your option) any later version.
//
/// @file AP_Var.cpp
/// @brief The AP variable store.
#define NO_AP_PARAM
#include <AP_Common.h>
#include <AP_Var.h>
#include <math.h>
#include <string.h>
//#define ENABLE_FASTSERIAL_DEBUG
#ifdef ENABLE_FASTSERIAL_DEBUG
# include <FastSerial.h>
# define serialDebug(fmt, args...) if (FastSerial::getInitialized(0)) do {Serial.printf("%s:%d: " fmt "\n", __FUNCTION__, __LINE__ , ##args); delay(0); } while(0)
#else
# define serialDebug(fmt, args...)
#endif
// Global constants exported for general use.
//
AP_Float AP_Float_unity ( 1.0, AP_Var::k_key_none, NULL, AP_Var::k_flag_unlisted);
AP_Float AP_Float_negative_unity(-1.0, AP_Var::k_key_none, NULL, AP_Var::k_flag_unlisted);
AP_Float AP_Float_zero ( 0.0, AP_Var::k_key_none, NULL, AP_Var::k_flag_unlisted);
// Static member variables for AP_Var.
//
AP_Var *AP_Var::_variables;
AP_Var *AP_Var::_grouped_variables;
uint16_t AP_Var::_tail_sentinel;
uint16_t AP_Var::_bytes_in_use;
// Constructor for standalone variables
//
AP_Var::AP_Var(Key p_key, const prog_char_t *name, Flags flags) :
_group(NULL),
_key(p_key | k_key_not_located),
_name(name),
_flags(flags)
{
// Insert the variable or group into the list of known variables, unless
// it wants to be unlisted.
//
if (!has_flags(k_flag_unlisted)) {
_link = _variables;
_variables = this;
}
}
// Constructor for variables in a group
//
AP_Var::AP_Var(AP_Var_group *pGroup, Key index, const prog_char_t *name, Flags flags) :
_group(pGroup),
_key(index),
_name(name),
_flags(flags)
{
AP_Var **vp;
// Sort the variable into the list of group-member variables.
//
// This list is kept sorted so that groups can traverse forwards along
// it in order to enumerate their members in key order.
//
// We use a pointer-to-pointer insertion technique here; vp points
// to the pointer to the node that we are considering inserting in front of.
//
vp = &_grouped_variables;
size_t loopCount = 0;
while (*vp != NULL) {
if (loopCount++>k_num_max) return;
if ((*vp)->_key >= _key) {
break;
}
vp = &((*vp)->_link);
}
_link = *vp;
*vp = this;
}
// Destructor
//
AP_Var::~AP_Var(void)
{
AP_Var **vp;
// Determine which list the variable may be in.
// If the variable is a group member and the group has already
// been destroyed, it may not be in any list.
//
if (_group) {
vp = &_grouped_variables;
} else {
vp = &_variables;
}
// Scan the list and remove this if we find it
{
size_t loopCount = 0;
while (*vp) {
if (loopCount++>k_num_max) return;
if (*vp == this) {
*vp = _link;
break;
}
vp = &((*vp)->_link);
}
}
// If we are destroying a group, remove all its variables from the list
//
if (has_flags(k_flag_is_group)) {
// Scan the list and remove any variable that has this as its group
vp = &_grouped_variables;
size_t loopCount = 0;
while (*vp) {
if (loopCount++>k_num_max) return;
// Does the variable claim us as its group?
if ((*vp)->_group == this) {
*vp = (*vp)->_link;
continue;
}
vp = &((*vp)->_link);
}
}
}
// Copy the variable's whole name to the supplied buffer.
//
// If the variable is a group member, prepend the group name.
//
void AP_Var::copy_name(char *buffer, size_t buffer_size) const
{
buffer[0] = '\0';
if (_name) {
if (_group)
_group->copy_name(buffer, buffer_size);
strlcat_P(buffer, _name, buffer_size);
}
}
// Find a variable by name.
//
AP_Var *
AP_Var::find(const char *name)
{
AP_Var *vp;
size_t loopCount = 0;
for (vp = first(); vp; vp = vp->next()) {
if (loopCount++>k_num_max) return NULL;
char name_buffer[32];
// copy the variable's name into our scratch buffer
vp->copy_name(name_buffer, sizeof(name_buffer));
// compare with the user-supplied name
if (!strcmp(name, name_buffer)) {
return vp;
}
}
return NULL;
}
// Find a variable by key.
//
AP_Var *
AP_Var::find(Key key)
{
AP_Var *vp;
size_t loopCount = 0;
for (vp = first(); vp; vp = vp->next()) {
if (loopCount++>k_num_max) return NULL;
if (key == vp->key()) {
return vp;
}
}
return NULL;
}
// Save the variable to EEPROM, if supported
//
bool AP_Var::save(void)
{
uint8_t vbuf[k_size_max];
size_t size;
// if the variable is a group member, save the group
if (_group) {
return _group->save();
}
serialDebug("save: %S", _name ? _name : PSTR("??"));
// locate the variable in EEPROM, allocating space as required
if (!_EEPROM_locate(true)) {
serialDebug("locate failed");
return false;
}
// serialize the variable into the buffer and work out how big it is
size = serialize(vbuf, sizeof(vbuf));
if (0 == size) {
// variable cannot be serialised into the buffer
serialDebug("cannot save (too big or not supported)");
return false;
}
// if it fit in the buffer, save it to EEPROM
if (size <= sizeof(vbuf)) {
serialDebug("saving %u to %u", size, _key);
// XXX this should use eeprom_update_block if/when Arduino moves to
// avr-libc >= 1.7
uint8_t *ep = (uint8_t *)_key;
for (size_t i = 0; i < size; i++, ep++) {
uint8_t newv;
// if value needs to change, change it
if (eeprom_read_byte(ep) != vbuf[i])
eeprom_write_byte(ep, vbuf[i]);
// now read it back
newv = eeprom_read_byte(ep);
if (newv != vbuf[i]) {
serialDebug("readback failed at offset %p: got %u, expected %u",
ep, newv, vbuf[i]);
return false;
}
}
return true;
}
return false;
}
// Load the variable from EEPROM, if supported
//
bool AP_Var::load(void)
{
uint8_t vbuf[k_size_max];
size_t size;
// if the variable is a group member, load the group
if (_group) {
return _group->load();
}
serialDebug("load: %S", _name ? _name : PSTR("??"));
// locate the variable in EEPROM, but do not allocate space
if (!_EEPROM_locate(false)) {
serialDebug("locate failed");
return false;
}
// ask the serializer how big the variable is
//
// XXX should check size in EEPROM var header too...
//
size = serialize(NULL, 0);
if (0 == size) {
serialDebug("cannot load (too big or not supported)");
return false;
}
// Read the buffer from EEPROM, now that _EEPROM_locate
// has converted _key into an EEPROM address.
//
if (size <= sizeof(vbuf)) {
serialDebug("loading %u from %u", size, _key);
eeprom_read_block(vbuf, (void *)_key, size);
return unserialize(vbuf, size);
}
return false;
}
// Save all variables that don't opt out.
//
//
bool AP_Var::save_all(void)
{
bool result = true;
AP_Var *vp = _variables;
size_t loopCount = 0;
while (vp) {
if (loopCount++>k_num_max) return false;
if (!vp->has_flags(k_flag_no_auto_load) && // not opted out of autosave
(vp->_key != k_key_none)) { // has a key
if (!vp->save()) {
result = false;
}
}
vp = vp->_link;
}
return result;
}
// Load all variables that don't opt out.
//
bool AP_Var::load_all(void)
{
bool result = true;
AP_Var *vp = _variables;
size_t loopCount = 0;
while (vp) {
if (loopCount++>k_num_max) return false;
if (!vp->has_flags(k_flag_no_auto_load) && // not opted out of autoload
(vp->_key != k_key_none)) { // has a key
if (!vp->load()) {
result = false;
}
}
vp = vp->_link;
}
return result;
}
// Erase all variables in EEPROM.
//
// We first walk the variable set and recover their key values
// from EEPROM, so that we have a chance of saving them later.
//
void
AP_Var::erase_all()
{
AP_Var *vp;
uint16_t i;
serialDebug("erase EEPROM");
// Scan the list of variables/groups, fetching their key values and
// reverting them to their not-located state.
//
vp = _variables;
size_t loopCount = 0;
while (vp) {
if (loopCount++>k_num_max) return;
vp->_key = vp->key() | k_key_not_located;
vp = vp->_link;
}
// wipe the whole EEPROM, including waypoints, as we call this
// on firmware revison changes, which may include a change to the
// waypoint format
for (i = 0; i < k_EEPROM_size; i++) {
eeprom_write_byte((uint8_t *)i, 0xff);
}
// revert to ignorance about the state of the EEPROM
_tail_sentinel = 0;
}
// Return the key for a variable.
//
AP_Var::Key
AP_Var::key(void)
{
Var_header var_header;
if (_group) { // group members don't have keys
return k_key_none;
}
if (_key & k_key_not_located) { // if not located, key is in memory
return _key & k_key_mask;
}
// Read key from EEPROM, note that _key points to the space
// allocated for storage; the header is immediately before.
//
eeprom_read_block(&var_header, (void *)(_key - sizeof(var_header)), sizeof(var_header));
return var_header.key;
}
// Default implementation of cast_to_float, which always fails.
//
float
AP_Var::cast_to_float(void) const
{
return NAN;
}
// Return the next variable in the global list.
//
AP_Var *
AP_Var::next(void)
{
// If there is a variable after this one, return it.
//
if (_link)
return _link;
// If we are at the end of the _variables list, _group will be NULL; in that
// case, move to the _grouped_variables list.
//
if (!_group) {
return _grouped_variables;
}
// We must be at the end of the _grouped_variables list, nothing remains.
//
return NULL;
}
// Return the first variable that is a member of the group.
//
AP_Var *
AP_Var::first_member(AP_Var_group *group)
{
AP_Var **vp;
vp = &_grouped_variables;
serialDebug("seeking %p", group);
size_t loopCount = 0;
while (*vp) {
if (loopCount++>k_num_max) return NULL;
serialDebug("consider %p with %p", *vp, (*vp)->_group);
if ((*vp)->_group == group) {
return *vp;
}
vp = &((*vp)->_link);
}
return NULL;
}
// Return the next variable that is a member of the same group.
AP_Var *
AP_Var::next_member()
{
AP_Var *vp;
vp = _link;
size_t loopCount = 0;
while (vp) {
if (loopCount++>k_num_max) return NULL;
if (vp->_group == _group) {
return vp;
}
vp = vp->_link;
}
return NULL;
}
// Scan the EEPROM and assign addresses to all the variables that
// are known and found therein.
//
bool AP_Var::_EEPROM_scan(void)
{
struct EEPROM_header ee_header;
struct Var_header var_header;
AP_Var *vp;
uint16_t eeprom_address;
// Assume that the EEPROM contents are invalid
_tail_sentinel = 0;
// read the header and validate
eeprom_address = 0;
eeprom_read_block(&ee_header, (void *)eeprom_address, sizeof(ee_header));
if ((ee_header.magic != k_EEPROM_magic) ||
(ee_header.revision != k_EEPROM_revision)) {
serialDebug("no header, magic 0x%x revision %u", ee_header.magic, ee_header.revision);
return false;
}
// scan the EEPROM
//
// Avoid trying to read a header when there isn't enough space left.
//
eeprom_address = sizeof(ee_header);
size_t loopCount = 0;
while (eeprom_address < (k_EEPROM_size - sizeof(var_header) - 1)) {
if (loopCount++>k_num_max) return NULL;
// Read a variable header
//
serialDebug("reading header from %u", eeprom_address);
eeprom_read_block(&var_header, (void *)eeprom_address, sizeof(var_header));
// If the header is for the sentinel, scanning is complete
//
if (var_header.key == k_key_sentinel) {
serialDebug("found tail sentinel");
break;
}
// Sanity-check the variable header and abort if it looks bad
//
if (k_EEPROM_size <= (
eeprom_address + // current position
sizeof(var_header) + // header for this variable
var_header.size + 1 + // data for this variable
sizeof(var_header))) { // header for sentinel
serialDebug("header overruns EEPROM");
return false;
}
// look for a variable with this key
vp = _variables;
size_t loopCount2 = 0;
while(vp) {
if (loopCount2++>k_num_max) return false;
if (vp->key() == var_header.key) {
// adjust the variable's key to point to this entry
vp->_key = eeprom_address + sizeof(var_header);
serialDebug("update %p with key %u -> %u", vp, var_header.key, vp->_key);
break;
}
vp = vp->_link;
}
if (!vp) {
serialDebug("key %u not claimed (already scanned or unknown)", var_header.key);
}
// move to the next variable header
eeprom_address += sizeof(var_header) + var_header.size + 1;
}
// Mark any variables that weren't assigned addresses as not-allocated,
// so that we don't waste time looking for them again later.
//
// Note that this isn't done when the header is not found on an empty EEPROM.
// The first variable written on an empty EEPROM falls out as soon as the
// header is not found. The second will scan and find one variable, then
// mark all the rest as not allocated.
//
vp = _variables;
size_t loopCount3 = 0;
while(vp) {
if (loopCount3++>k_num_max) return false;
if (vp->_key & k_key_not_located) {
vp->_key |= k_key_not_allocated;
serialDebug("key %u not allocated", vp->key());
}
vp = vp->_link;
}
// Scanning is complete
serialDebug("scan done");
_tail_sentinel = eeprom_address;
return true;
}
// Locate a variable in EEPROM, allocating space if required.
//
bool AP_Var::_EEPROM_locate(bool allocate)
{
Var_header var_header;
Key new_location;
size_t size;
// Is it a group member, or does it have a no-location key?
//
if (_group || (_key == k_key_none)) {
serialDebug("not addressable");
return false; // it is/does, and thus it has no location
}
// Has the variable already been located?
//
if (!(_key & k_key_not_located)) {
return true; // it has
}
// We don't know where this variable belongs. If the variable isn't
// marked as already having been looked for and not found in EEPROM,
// try scanning to see if we can locate it.
//
if (!(_key & k_key_not_allocated)) {
serialDebug("need scan");
_EEPROM_scan();
// Has the variable now been located?
//
if (!(_key & k_key_not_located)) {
return true; // it has
}
}
// If not located and not permitted to allocate, we have failed.
//
if (!allocate) {
return false;
}
serialDebug("needs allocation");
// Ask the serializer for the size of the thing we are allocating, and fail
// if it is too large or if it has no size, as we will not be able to allocate
// space for it.
//
size = serialize(NULL, 0);
if ((size == 0) || (size > k_size_max)) {
serialDebug("size %u out of bounds", size);
return false;
}
// Make sure there will be space in the EEPROM for the variable, its
// header and the new tail sentinel.
//
if ((_tail_sentinel + size + sizeof(Var_header) * 2) > k_EEPROM_size) {
serialDebug("no space in EEPROM");
return false;
}
// If there is no data in the EEPROM, write the header and move the
// sentinel.
//
if (0 == _tail_sentinel) {
uint8_t pad_size;
serialDebug("writing header");
EEPROM_header ee_header;
ee_header.magic = k_EEPROM_magic;
ee_header.revision = k_EEPROM_revision;
ee_header.spare = 0;
eeprom_write_block(&ee_header, (void *)0, sizeof(ee_header));
_tail_sentinel = sizeof(ee_header);
// Write a variable-sized pad header with a reserved key value
// to help wear-level the EEPROM a bit.
pad_size = (((uint8_t)micros()) % k_size_max) + 1; // should be fairly random
var_header.key = k_key_pad;
var_header.size = pad_size - 1;
var_header.spare = 0;
eeprom_write_block(&var_header, (void *)_tail_sentinel, sizeof(var_header));
_tail_sentinel += sizeof(var_header) + pad_size;
}
// Save the location we are going to insert at, and compute the new
// tail sentinel location.
//
new_location = _tail_sentinel;
_tail_sentinel += sizeof(var_header) + size;
serialDebug("allocated %u/%u for key %u new sentinel %u", new_location, size, key(), _tail_sentinel);
// Write the new sentinel first. If we are interrupted during this operation
// the old sentinel will still correctly terminate the EEPROM image.
//
var_header.key = k_key_sentinel;
var_header.size = 0;
var_header.spare = 0;
eeprom_write_block(&var_header, (void *)_tail_sentinel, sizeof(var_header));
// Write the header for the block we have just located, claiming the EEPROM space.
//
var_header.key = key();
var_header.size = size - 1;
eeprom_write_block(&var_header, (void *)new_location, sizeof(var_header));
// We have successfully allocated space and thus located the variable.
// Update _key to point to the space allocated for it.
//
_key = new_location + sizeof(var_header);
return true;
}
size_t
AP_Var_group::serialize(void *buf, size_t buf_size) const
{
// We have to cast away the const in order to call _serialize_unserialize,
// as it cannot be const due to changing this when called to unserialize.
//
// XXX it's questionable how much advantage we get from having ::serialize
// const in the first place...
//
return const_cast<AP_Var_group *>(this)->_serialize_unserialize(buf, buf_size, true);
}
size_t
AP_Var_group::unserialize(void *buf, size_t buf_size)
{
return _serialize_unserialize(buf, buf_size, false);
}
size_t
AP_Var_group::_serialize_unserialize(void *buf, size_t buf_size, bool do_serialize)
{
AP_Var *vp;
size_t size, total_size;
// Traverse the list of group members, serializing each in order
//
vp = first_member(this);
serialDebug("starting with %p", vp);
total_size = 0;
size_t loopCount = 0;
while (vp) {
if (loopCount++>k_num_max) return false;
// (un)serialise the group member
if (do_serialize) {
size = vp->serialize(buf, buf_size);
serialDebug("serialize %p -> %u", vp, size);
} else {
size = vp->unserialize(buf, buf_size);
serialDebug("unserialize %p -> %u", vp, size);
}
// Unserialize will return zero if the buffer is too small
// Serialize will only return zero if the variable cannot be serialised
// Either case is fatal for any operation we might be trying.
//
if (0 == size) {
serialDebug("group (un)serialize failed, buffer too small or not supported");
return 0;
}
// Account for the space that this variable consumes in the buffer
//
// We always count the total size, and we always advance the buffer pointer
// if there was room for the variable. This does mean that in the case where
// the buffer was too small for a variable in the middle of the group, that
// a smaller variable after it in the group may still be serialised into
// the buffer. Since that's a rare case it's not worth optimising for - in
// either case this function will return a size greater than the buffer size
// and the calling function will have to treat it as an error.
//
total_size += size;
serialDebug("used %u", total_size);
if (size <= buf_size) {
// there was space for this one, account for it
buf_size -= size;
buf = (void *)((uint8_t *)buf + size);
}
vp = vp->next_member();
}
return total_size;
}
// Static pseudo-constant type IDs for known AP_VarT subclasses.
//
AP_Meta_class::Type_id AP_Var::k_typeid_float; ///< meta_type_id() value for AP_Float
AP_Meta_class::Type_id AP_Var::k_typeid_float16; ///< meta_type_id() value for AP_Float16
AP_Meta_class::Type_id AP_Var::k_typeid_int32; ///< meta_type_id() value for AP_Int32
AP_Meta_class::Type_id AP_Var::k_typeid_int16; ///< meta_type_id() value for AP_Int16
AP_Meta_class::Type_id AP_Var::k_typeid_int8; ///< meta_type_id() value for AP_Int8
AP_Meta_class::Type_id AP_Var::k_typeid_group; ///< meta_type_id() value for AP_Var_group
/// A special class used to initialise the k_typeid_* values that AP_Var exports.
///
class AP_Var_typesetup
{
public:
/// Constructor
///
/// This constructor should be run just once by creating a static instance
/// of the class. It will initialise the k_typeid_* values for the well-known
/// AP_VarT subclasses.
///
/// When a new subclass is created, a new k_typeid_* constant should also be
/// created and the list below should likewise be expanded.
///
AP_Var_typesetup(void);
};
/// Initialise AP_Var's k_typeid_* values
AP_Var_typesetup::AP_Var_typesetup(void)
{
AP_Var::k_typeid_float = AP_Meta_class::meta_type_id<AP_Float>();
AP_Var::k_typeid_float16 = AP_Meta_class::meta_type_id<AP_Float16>();
AP_Var::k_typeid_int32 = AP_Meta_class::meta_type_id<AP_Int32>();
AP_Var::k_typeid_int16 = AP_Meta_class::meta_type_id<AP_Int16>();
AP_Var::k_typeid_int8 = AP_Meta_class::meta_type_id<AP_Int8>();
AP_Var::k_typeid_group = AP_Meta_class::meta_type_id<AP_Var_group>();
}
/// Cause the AP_Var_typesetup constructor to be run.
///
static AP_Var_typesetup _typesetup __attribute__((used));
#endif
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