ardupilot/libraries/AP_Common/AP_Param.h

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// -*- 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_Param.h
/// @brief A system for managing and storing variables that are of
/// general interest to the system.
#ifndef AP_PARAM_H
#define AP_PARAM_H
#include <stddef.h>
#include <string.h>
#include <stdint.h>
#include <avr/pgmspace.h>
#include <avr/eeprom.h>
#define AP_MAX_NAME_SIZE 15
// a varient of offsetof() to work around C++ restrictions.
// this can only be used when the offset of a variable in a object
// is constant and known at compile time
#define AP_VAROFFSET(type, element) (((uintptr_t)(&((const type *)1)->element))-1)
// find the type of a variable given the class and element
#define AP_CLASSTYPE(class, element) (((const class *)1)->element.vtype)
// declare a group var_info line
#define AP_GROUPINFO(name, idx, class, element) { AP_CLASSTYPE(class, element), idx, name, AP_VAROFFSET(class, element) }
// declare a nested group entry in a group var_info
#define AP_NESTEDGROUPINFO(class, idx) { AP_PARAM_GROUP, idx, "", 0, class::var_info }
#define AP_GROUPEND { AP_PARAM_NONE, 0xFF, "" }
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enum ap_var_type {
AP_PARAM_NONE = 0,
AP_PARAM_INT8,
AP_PARAM_INT16,
AP_PARAM_INT32,
AP_PARAM_FLOAT,
AP_PARAM_VECTOR3F,
AP_PARAM_VECTOR6F,
AP_PARAM_MATRIX3F,
AP_PARAM_GROUP
};
/// Base class for variables.
///
/// Provides naming and lookup services for variables.
///
class AP_Param
{
public:
// the Info and GroupInfo structures are passed by the main
// program in setup() to give information on how variables are
// named and their location in memory
struct GroupInfo {
uint8_t type; // AP_PARAM_*
uint8_t idx; // identifier within the group
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const char name[AP_MAX_NAME_SIZE];
uintptr_t offset; // offset within the object
const struct GroupInfo *group_info;
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};
struct Info {
uint8_t type; // AP_PARAM_*
const char name[AP_MAX_NAME_SIZE];
uint8_t key; // k_param_*
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void *ptr; // pointer to the variable in memory
const struct GroupInfo *group_info;
};
// a token used for first()/next() state
typedef struct {
uint8_t key;
uint8_t group_element;
uint8_t idx; // offset into array types
} ParamToken;
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// called once at startup to setup the _var_info[] table. This
// will also check the EEPROM header and re-initialise it if the
// wrong version is found
static bool setup(const struct Info *info, uint8_t num_vars, uint16_t eeprom_size);
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// return true if AP_Param has been initialised via setup()
static bool initialised(void);
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/// Copy the variable's name, prefixed by any containing group name, to a buffer.
///
/// If the variable has no name, the buffer will contain an empty string.
///
/// Note that if the combination of names is larger than the buffer, the
/// result in the buffer will be truncated.
///
/// @param buffer The destination buffer
/// @param bufferSize Total size of the destination buffer.
///
void copy_name(char *buffer, size_t bufferSize, bool force_scalar=false);
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/// Find a variable by name.
///
/// If the variable has no name, it cannot be found by this interface.
///
/// @param name The full name of the variable to be found.
/// @return A pointer to the variable, or NULL if
/// it does not exist.
///
static AP_Param *find(const char *name, enum ap_var_type *ptype);
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/// Save the current value of the variable to EEPROM.
///
/// @return True if the variable was saved successfully.
///
bool save(void);
/// Load the variable from EEPROM.
///
/// @return True if the variable was loaded successfully.
///
bool load(void);
/// Load all variables from EEPROM
///
/// This function performs a best-efforts attempt to load all
/// of the variables from EEPROM. If some fail to load, their
/// values will remain as they are.
///
/// @return False if any variable failed to load
///
static bool load_all(void);
/// Erase all variables in EEPROM.
///
static void erase_all(void);
/// print the value of all variables
static void show_all(void);
/// Returns the first variable
///
/// @return The first variable in _var_info, or NULL if
/// there are none.
///
static AP_Param *first(ParamToken *token, enum ap_var_type *ptype);
/// Returns the next variable in _var_info, recursing into groups
/// as needed
static AP_Param *next(ParamToken *token, enum ap_var_type *ptype);
/// Returns the next scalar variable in _var_info, recursing into groups
/// as needed
static AP_Param *next_scalar(ParamToken *token, enum ap_var_type *ptype);
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/// cast a variable to a float given its type
float cast_to_float(enum ap_var_type type);
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private:
/// EEPROM header
///
/// This structure is placed at the head of the EEPROM to indicate
/// that the ROM is formatted for AP_Param.
///
struct EEPROM_header {
uint8_t magic[2];
uint8_t revision;
uint8_t spare;
};
// This header is prepended to a variable stored in EEPROM.
struct Param_header {
uint8_t key;
uint8_t group_element;
uint8_t type;
};
// number of bits in each level of nesting of groups
static const uint8_t _group_level_shift = 4;
static const uint8_t _group_bits = 8;
static const uint8_t _sentinal_key = 0xFF;
static const uint8_t _sentinal_type = 0xFF;
static const uint8_t _sentinal_group = 0xFF;
static bool check_group_info(const struct GroupInfo *group_info, uint16_t *total_size, uint8_t max_bits);
static bool check_var_info(void);
const struct Info *find_var_info_group(const struct GroupInfo *group_info,
uint8_t vindex,
uint8_t group_base,
uint8_t group_shift,
uint8_t *group_element,
const struct GroupInfo **group_ret,
uint8_t *idx);
const struct Info *find_var_info(uint8_t *group_element,
const struct GroupInfo **group_ret,
uint8_t *idx);
static const struct Info *find_by_header_group(struct Param_header phdr, void **ptr,
uint8_t vindex,
const struct GroupInfo *group_info,
uint8_t group_base,
uint8_t group_shift);
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static const struct Info *find_by_header(struct Param_header phdr, void **ptr);
void add_vector3f_suffix(char *buffer, size_t buffer_size, uint8_t idx);
static AP_Param *find_group(const char *name, uint8_t vindex, const struct GroupInfo *group_info, enum ap_var_type *ptype);
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static void write_sentinal(uint16_t ofs);
bool scan(const struct Param_header *phdr, uint16_t *pofs);
static const uint8_t type_size(enum ap_var_type type);
static void eeprom_write_check(const void *ptr, uint16_t ofs, uint8_t size);
static AP_Param *next_group(uint8_t vindex, const struct GroupInfo *group_info,
bool *found_current,
uint8_t group_base,
uint8_t group_shift,
ParamToken *token,
enum ap_var_type *ptype);
static uint16_t _eeprom_size;
static uint8_t _num_vars;
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static const struct Info *_var_info;
// values filled into the EEPROM header
static const uint8_t k_EEPROM_magic0 = 0x50;
static const uint8_t k_EEPROM_magic1 = 0x41; ///< "AP"
static const uint8_t k_EEPROM_revision = 5; ///< current format revision
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};
/// Template class for scalar variables.
///
/// Objects of this type have a value, and can be treated in many ways as though they
/// were the value.
///
/// @tparam T The scalar type of the variable
/// @tparam PT The AP_PARAM_* type
///
template<typename T, ap_var_type PT>
class AP_ParamT : public AP_Param
{
public:
/// Constructor for scalar variable.
///
/// Initialises a stand-alone variable with optional initial value.
///
/// @param default_value Value the variable should have at startup.
///
AP_ParamT<T,PT> (const T initial_value = 0) :
AP_Param(),
_value(initial_value)
{
}
static const ap_var_type vtype = PT;
/// Value getter
///
T get(void) const {
return _value;
}
/// Value setter
///
void set(T v) {
_value = v;
}
/// Combined set and save
///
bool set_and_save(T v) {
set(v);
return save();
}
/// Combined set and save, but only does the save if the value if
/// different from the current ram value, thus saving us a
/// scan(). This should only be used where we have not set() the
/// value separately, as otherwise the value in EEPROM won't be
/// updated correctly.
bool set_and_save_ifchanged(T v) {
if (v == _value) {
return true;
}
set(v);
return save();
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}
/// Conversion to T returns a reference to the value.
///
/// This allows the class to be used in many situations where the value would be legal.
///
operator T &() {
return _value;
}
/// Copy assignment from self does nothing.
///
AP_ParamT<T,PT>& operator=(AP_ParamT<T,PT>& v) {
return v;
}
/// Copy assignment from T is equivalent to ::set.
///
AP_ParamT<T,PT>& operator=(T v) {
_value = v;
return *this;
}
/// AP_ParamT types can implement AP_Param::cast_to_float
///
float cast_to_float(void) {
return (float)_value;
}
protected:
T _value;
};
/// Template class for non-scalar variables.
///
/// Objects of this type have a value, and can be treated in many ways as though they
/// were the value.
///
/// @tparam T The scalar type of the variable
/// @tparam PT AP_PARAM_* type
///
template<typename T, ap_var_type PT>
class AP_ParamV : public AP_Param
{
public:
static const ap_var_type vtype = PT;
/// Value getter
///
T get(void) const {
return _value;
}
/// Value setter
///
void set(T v) {
_value = v;
}
/// Combined set and save
///
bool set_and_save(T v) {
set(v);
return save();
}
/// Conversion to T returns a reference to the value.
///
/// This allows the class to be used in many situations where the value would be legal.
///
operator T &() {
return _value;
}
/// Copy assignment from self does nothing.
///
AP_ParamV<T,PT>& operator=(AP_ParamV<T,PT>& v) {
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return v;
}
/// Copy assignment from T is equivalent to ::set.
///
AP_ParamV<T,PT>& operator=(T v) {
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_value = v;
return *this;
}
protected:
T _value;
};
/// Template class for array variables.
///
/// Objects created using this template behave like arrays of the type T,
/// but are stored like single variables.
///
/// @tparam T The scalar type of the variable
/// @tparam N number of elements
/// @tparam PT the AP_PARAM_* type
///
template<typename T, uint8_t N, ap_var_type PT>
class AP_ParamA : public AP_Param
{
public:
static const ap_var_type vtype = PT;
/// Array operator accesses members.
///
/// @note It would be nice to range-check i here, but then what would we return?
///
T &operator [](uint8_t i) {
return _value[i];
}
/// Value getter
///
/// @note Returns zero for index values out of range.
///
T get(uint8_t i) const {
if (i < N) {
return _value[i];
} else {
return (T)0;
}
}
/// Value setter
///
/// @note Attempts to set an index out of range are discarded.
///
void set(uint8_t i, T v) {
if (i < N) {
_value[i] = v;
}
}
/// Copy assignment from self does nothing.
///
AP_ParamA<T,N,PT>& operator=(AP_ParamA<T,N,PT>& v) {
return v;
}
protected:
T _value[N];
};
/// Convenience macro for defining instances of the AP_ParamT template.
///
// declare a scalar type
// _t is the base type
// _suffix is the suffix on the AP_* type name
// _pt is the enum ap_var_type type
#define AP_PARAMDEF(_t, _suffix, _pt) typedef AP_ParamT<_t, _pt> AP_##_suffix;
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AP_PARAMDEF(float, Float, AP_PARAM_FLOAT); // defines AP_Float
AP_PARAMDEF(int8_t, Int8, AP_PARAM_INT8); // defines AP_Int8
AP_PARAMDEF(int16_t, Int16, AP_PARAM_INT16); // defines AP_Int16
AP_PARAMDEF(int32_t, Int32, AP_PARAM_INT32); // defines AP_Int32
// declare an array type
// _t is the base type
// _suffix is the suffix on the AP_* type name
// _size is the size of the array
// _pt is the enum ap_var_type type
#define AP_PARAMDEFA(_t, _suffix, _size, _pt) typedef AP_ParamA<_t, _size, _pt> AP_##_suffix;
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AP_PARAMDEFA(float, Vector6f, 6, AP_PARAM_VECTOR6F);
// declare a non-scalar type
// this is used in AP_Math.h
// _t is the base type
// _suffix is the suffix on the AP_* type name
// _pt is the enum ap_var_type type
#define AP_PARAMDEFV(_t, _suffix, _pt) typedef AP_ParamV<_t, _pt> AP_##_suffix;
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/// Rely on built in casting for other variable types
/// to minimize template creation and save memory
#define AP_Uint8 AP_Int8
#define AP_Uint16 AP_Int16
#define AP_Uint32 AP_Int32
#define AP_Bool AP_Int8
#endif // AP_PARAM_H