esp-nimble-cpp/src/NimBLEAttValue.h

/*
 * NimBLEAttValue.h
 *
 *  Created: on March 18, 2021
 *      Author H2zero
 *
 */

#ifndef MAIN_NIMBLEATTVALUE_H_
#define MAIN_NIMBLEATTVALUE_H_
#include "nimconfig.h"
#if defined(CONFIG_BT_ENABLED)

#ifdef NIMBLE_CPP_ARDUINO_STRING_AVAILABLE
#include <Arduino.h>
#endif

#include "NimBLELog.h"

/****  FIX COMPILATION ****/
#undef min
#undef max
/**************************/

#include <string>
#include <vector>
#include <ctime>

#ifndef CONFIG_NIMBLE_CPP_ATT_VALUE_TIMESTAMP_ENABLED
#    define CONFIG_NIMBLE_CPP_ATT_VALUE_TIMESTAMP_ENABLED 0
#endif

#if CONFIG_NIMBLE_CPP_ATT_VALUE_TIMESTAMP_ENABLED
#    include <time.h>
#endif

#if !defined(CONFIG_NIMBLE_CPP_ATT_VALUE_INIT_LENGTH)
#    define CONFIG_NIMBLE_CPP_ATT_VALUE_INIT_LENGTH 20
#elif CONFIG_NIMBLE_CPP_ATT_VALUE_INIT_LENGTH > BLE_ATT_ATTR_MAX_LEN
#    error CONFIG_NIMBLE_CPP_ATT_VALUE_INIT_LENGTH cannot be larger than 512 (BLE_ATT_ATTR_MAX_LEN)
#elif CONFIG_NIMBLE_CPP_ATT_VALUE_INIT_LENGTH < 1
#    error CONFIG_NIMBLE_CPP_ATT_VALUE_INIT_LENGTH cannot be less than 1; Range = 1 : 512
#endif

/* Used to determine if the type passed to a template has a c_str() and length() method. */
template <typename T, typename = void, typename = void>
struct Has_c_str_len : std::false_type {};

template <typename T>
struct Has_c_str_len<T, decltype(void(std::declval<T &>().c_str())),
                     decltype(void(std::declval<T &>().length()))> : std::true_type {};


/**
 * @brief A specialized container class to hold BLE attribute values.
 * @details This class is designed to be more memory efficient than using\n
 * standard container types for value storage, while being convertible to\n
 * many different container classes.
 */
class NimBLEAttValue
{
    uint8_t*     m_attr_value = nullptr;
    uint16_t     m_attr_max_len = 0;
    uint16_t     m_attr_len = 0;
    uint16_t     m_capacity = 0;
#if CONFIG_NIMBLE_CPP_ATT_VALUE_TIMESTAMP_ENABLED
    time_t       m_timestamp = 0;
#endif
    void         deepCopy(const NimBLEAttValue & source);

public:
    /**
     * @brief Default constructor.
     * @param[in] init_len The initial size in bytes.
     * @param[in] max_len The max size in bytes that the value can be.
     */
    NimBLEAttValue(uint16_t init_len = CONFIG_NIMBLE_CPP_ATT_VALUE_INIT_LENGTH,
                   uint16_t max_len = BLE_ATT_ATTR_MAX_LEN);

    /**
     * @brief Construct with an initial value from a buffer.
     * @param value A pointer to the initial value to set.
     * @param[in] len The size in bytes of the value to set.
     * @param[in] max_len The max size in bytes that the value can be.
     */
    NimBLEAttValue(const uint8_t *value, uint16_t len,
                   uint16_t max_len = BLE_ATT_ATTR_MAX_LEN);

    /**
     * @brief Construct with an initializer list.
     * @param list An initializer list containing the initial value to set.
     * @param[in] max_len The max size in bytes that the value can be.
     */
    NimBLEAttValue(std::initializer_list<uint8_t> list,
                   uint16_t max_len = BLE_ATT_ATTR_MAX_LEN)
                   :NimBLEAttValue(list.begin(), (uint16_t)list.size(), max_len){}

    /**
     * @brief Construct with an initial value from a const char string.
     * @param value A pointer to the initial value to set.
     * @param[in] max_len The max size in bytes that the value can be.
     */
    NimBLEAttValue(const char *value, uint16_t max_len = BLE_ATT_ATTR_MAX_LEN)
                   :NimBLEAttValue((uint8_t*)value, (uint16_t)strlen(value), max_len){}

    /**
     * @brief Construct with an initial value from a std::string.
     * @param str A std::string containing to the initial value to set.
     * @param[in] max_len The max size in bytes that the value can be.
     */
    NimBLEAttValue(const std::string str, uint16_t max_len = BLE_ATT_ATTR_MAX_LEN)
                   :NimBLEAttValue((uint8_t*)str.data(), (uint16_t)str.length(), max_len){}

    /**
     * @brief Construct with an initial value from a std::vector<uint8_t>.
     * @param vec A std::vector<uint8_t> containing to the initial value to set.
     * @param[in] max_len The max size in bytes that the value can be.
     */
    NimBLEAttValue(const std::vector<uint8_t> vec, uint16_t max_len = BLE_ATT_ATTR_MAX_LEN)
                   :NimBLEAttValue(&vec[0], (uint16_t)vec.size(), max_len){}

#ifdef NIMBLE_CPP_ARDUINO_STRING_AVAILABLE
    /**
     * @brief Construct with an initial value from an Arduino String.
     * @param str An Arduino String containing to the initial value to set.
     * @param[in] max_len The max size in bytes that the value can be.
     */
    NimBLEAttValue(const String str, uint16_t max_len = BLE_ATT_ATTR_MAX_LEN)
                   :NimBLEAttValue((uint8_t*)str.c_str(), str.length(), max_len){}
#endif

    /** @brief Copy constructor */
    NimBLEAttValue(const NimBLEAttValue & source) { deepCopy(source); }

    /** @brief Move constructor */
    NimBLEAttValue(NimBLEAttValue && source) { *this = std::move(source); }

    /** @brief Destructor */
    ~NimBLEAttValue();

    /** @brief Returns the max size in bytes */
    uint16_t        max_size()     const   { return m_attr_max_len; }

    /** @brief Returns the currently allocated capacity in bytes */
    uint16_t        capacity()     const   { return m_capacity; }

    /** @brief Returns the current length of the value in bytes */
    uint16_t        length()       const   { return m_attr_len; }

    /** @brief Returns the current size of the value in bytes */
    uint16_t        size()         const   { return m_attr_len; }

    /** @brief Returns a pointer to the internal buffer of the value */
    const uint8_t*  data()         const   { return m_attr_value; }

    /** @brief Returns a pointer to the internal buffer of the value as a const char* */
    const char*     c_str()        const   { return (const char*)m_attr_value; }

    /** @brief Iterator begin */
    const uint8_t*  begin()        const   { return m_attr_value; }

    /** @brief Iterator end */
    const uint8_t*  end()          const   { return m_attr_value + m_attr_len; }

#if CONFIG_NIMBLE_CPP_ATT_VALUE_TIMESTAMP_ENABLED
    /** @brief Returns a timestamp of when the value was last updated */
    time_t          getTimeStamp() const   { return m_timestamp; }

    /** @brief Set the timestamp to the current time */
    void            setTimeStamp()         { m_timestamp = time(nullptr); }

    /**
     * @brief Set the timestamp to the specified time
     * @param[in] t The timestamp value to set
     */
    void            setTimeStamp(time_t t) { m_timestamp = t; }
#else
    time_t          getTimeStamp() const   { return 0; }
    void            setTimeStamp()         { }
    void            setTimeStamp(time_t t) { }
#endif

    /**
     * @brief Set the value from a buffer
     * @param[in] value A ponter to a buffer containing the value.
     * @param[in] len The length of the value in bytes.
     * @returns True if successful.
     */
    bool            setValue(const uint8_t *value, uint16_t len);

    /**
     * @brief Set value to the value of const char*.
     * @param [in] s A ponter to a const char value to set.
     */
    bool            setValue(const char* s) {
                         return setValue((uint8_t*)s, (uint16_t)strlen(s)); }

    /**
     * @brief Get a pointer to the value buffer with timestamp.
     * @param[in] timestamp A ponter to a time_t variable to store the timestamp.
     * @returns A pointer to the internal value buffer.
     */
    const uint8_t*  getValue(time_t *timestamp);

    /**
     * @brief Append data to the value.
     * @param[in] value A ponter to a data buffer with the value to append.
     * @param[in] len The length of the value to append in bytes.
     * @returns A reference to the appended NimBLEAttValue.
     */
    NimBLEAttValue& append(const uint8_t *value, uint16_t len);


    /*********************** Template Functions ************************/

    /**
     * @brief Template to set value to the value of <type\>val.
     * @param [in] s The <type\>value to set.
     * @details Only used for types without a `c_str()` method.
     */
    template<typename T>
#ifdef _DOXYGEN_
    bool
#else
    typename std::enable_if<!Has_c_str_len<T>::value, bool>::type
#endif
    setValue(const T &s) {
        return setValue((uint8_t*)&s, sizeof(T));
    }

    /**
     * @brief Template to set value to the value of <type\>val.
     * @param [in] s The <type\>value to set.
     * @details Only used if the <type\> has a `c_str()` method.
     */
    template<typename T>
#ifdef _DOXYGEN_
    bool
#else
    typename std::enable_if<Has_c_str_len<T>::value, bool>::type
#endif
    setValue(const T & s) {
        return setValue((uint8_t*)s.c_str(), (uint16_t)s.length());
    }

    /**
     * @brief Template to return the value as a <type\>.
     * @tparam T The type to convert the data to.
     * @param [in] timestamp A pointer to a time_t struct to store the time the value was read.
     * @param [in] skipSizeCheck If true it will skip checking if the data size is less than\n
     * <tt>sizeof(<type\>)</tt>.
     * @return The data converted to <type\> or NULL if skipSizeCheck is false and the data is\n
     * less than <tt>sizeof(<type\>)</tt>.
     * @details <b>Use:</b> <tt>getValue<type>(&timestamp, skipSizeCheck);</tt>
     */
    template<typename T>
    T   getValue(time_t *timestamp = nullptr, bool skipSizeCheck = false) {
            if(!skipSizeCheck && size() < sizeof(T)) {
                return T();
            }
            return *((T *)getValue(timestamp));
    }


    /*********************** Operators ************************/

    /** @brief Subscript operator */
    uint8_t operator [](int pos) const {
        NIMBLE_CPP_DEBUG_ASSERT(pos < m_attr_len);
        return m_attr_value[pos]; }

    /** @brief Operator; Get the value as a std::vector<uint8_t>. */
    operator std::vector<uint8_t>() const {
        return std::vector<uint8_t>(m_attr_value, m_attr_value + m_attr_len); }

    /** @brief Operator; Get the value as a std::string. */
    operator std::string() const {
        return std::string((char*)m_attr_value, m_attr_len); }

    /** @brief Operator; Get the value as a const uint8_t*. */
    operator const uint8_t*() const { return m_attr_value; }

    /** @brief Operator; Append another NimBLEAttValue. */
    NimBLEAttValue& operator  +=(const NimBLEAttValue & source) {
        return append(source.data(), source.size()); }

    /** @brief Operator; Set the value from a std::string source. */
    NimBLEAttValue& operator  =(const std::string & source) {
        setValue((uint8_t*)source.data(), (uint16_t)source.size()); return *this; }

    /** @brief Move assignment operator */
    NimBLEAttValue& operator  =(NimBLEAttValue && source);

    /** @brief Copy assignment operator */
    NimBLEAttValue& operator  =(const NimBLEAttValue & source);

    /** @brief Equality operator */
    bool operator  ==(const NimBLEAttValue & source) {
        return (m_attr_len == source.size()) ?
                memcmp(m_attr_value, source.data(), m_attr_len) == 0 : false; }

    /** @brief Inequality operator */
    bool operator  !=(const NimBLEAttValue & source){ return !(*this == source); }

#ifdef NIMBLE_CPP_ARDUINO_STRING_AVAILABLE
    /** @brief Operator; Get the value as an Arduino String value. */
    operator String() const { return String((char*)m_attr_value); }
#endif

};


inline NimBLEAttValue::NimBLEAttValue(uint16_t init_len, uint16_t max_len) {
    m_attr_value   = (uint8_t*)calloc(init_len + 1, 1);
    NIMBLE_CPP_DEBUG_ASSERT(m_attr_value);
    m_attr_max_len = std::min(BLE_ATT_ATTR_MAX_LEN, (int)max_len);
    m_attr_len     = 0;
    m_capacity     = init_len;
    setTimeStamp(0);
}

inline NimBLEAttValue::NimBLEAttValue(const uint8_t *value, uint16_t len, uint16_t max_len)
: NimBLEAttValue(len, max_len) {
    memcpy(m_attr_value, value, len);
    m_attr_value[len] = '\0';
    m_attr_len        = len;
}

inline NimBLEAttValue::~NimBLEAttValue() {
    if(m_attr_value != nullptr) {
        free(m_attr_value);
    }
}

inline NimBLEAttValue& NimBLEAttValue::operator =(NimBLEAttValue && source) {
    if (this != &source){
        free(m_attr_value);

        m_attr_value   = source.m_attr_value;
        m_attr_max_len = source.m_attr_max_len;
        m_attr_len     = source.m_attr_len;
        m_capacity     = source.m_capacity;
        setTimeStamp(source.getTimeStamp());
        source.m_attr_value = nullptr;
    }
    return *this;
}

inline NimBLEAttValue& NimBLEAttValue::operator =(const NimBLEAttValue & source) {
    if (this != &source) {
        deepCopy(source);
    }
    return *this;
}

inline void NimBLEAttValue::deepCopy(const NimBLEAttValue & source) {
    uint8_t* res = (uint8_t*)realloc( m_attr_value, source.m_capacity + 1);
    NIMBLE_CPP_DEBUG_ASSERT(res);

    ble_npl_hw_enter_critical();
    m_attr_value   = res;
    m_attr_max_len = source.m_attr_max_len;
    m_attr_len     = source.m_attr_len;
    m_capacity     = source.m_capacity;
    setTimeStamp(source.getTimeStamp());
    memcpy(m_attr_value, source.m_attr_value, m_attr_len + 1);
    ble_npl_hw_exit_critical(0);
}

inline const uint8_t*  NimBLEAttValue::getValue(time_t *timestamp) {
    if(timestamp != nullptr) {
#if CONFIG_NIMBLE_CPP_ATT_VALUE_TIMESTAMP_ENABLED
        *timestamp = m_timestamp;
#else
        *timestamp = 0;
#endif
    }
    return m_attr_value;
}

inline bool NimBLEAttValue::setValue(const uint8_t *value, uint16_t len) {
    if (len > m_attr_max_len) {
        NIMBLE_LOGE("NimBLEAttValue", "value exceeds max, len=%u, max=%u",
                     len, m_attr_max_len);
        return false;
    }

    uint8_t *res = m_attr_value;
    if (len > m_capacity) {
        res = (uint8_t*)realloc(m_attr_value, (len + 1));
        m_capacity = len;
    }
    NIMBLE_CPP_DEBUG_ASSERT(res);

#if CONFIG_NIMBLE_CPP_ATT_VALUE_TIMESTAMP_ENABLED
    time_t t = time(nullptr);
#else
    time_t t = 0;
#endif

    ble_npl_hw_enter_critical();
    m_attr_value = res;
    memcpy(m_attr_value, value, len);
    m_attr_value[len] = '\0';
    m_attr_len = len;
    setTimeStamp(t);
    ble_npl_hw_exit_critical(0);
    return true;
}

inline NimBLEAttValue& NimBLEAttValue::append(const uint8_t *value, uint16_t len) {
    if (len < 1) {
        return *this;
    }

    if ((m_attr_len + len) > m_attr_max_len) {
        NIMBLE_LOGE("NimBLEAttValue", "val > max, len=%u, max=%u",
                    len, m_attr_max_len);
        return *this;
    }

    uint8_t* res = m_attr_value;
    uint16_t new_len = m_attr_len + len;
    if (new_len > m_capacity) {
        res = (uint8_t*)realloc(m_attr_value, (new_len + 1));
        m_capacity = new_len;
    }
    NIMBLE_CPP_DEBUG_ASSERT(res);

#if CONFIG_NIMBLE_CPP_ATT_VALUE_TIMESTAMP_ENABLED
    time_t t = time(nullptr);
#else
    time_t t = 0;
#endif

    ble_npl_hw_enter_critical();
    m_attr_value = res;
    memcpy(m_attr_value + m_attr_len, value, len);
    m_attr_len = new_len;
    m_attr_value[m_attr_len] = '\0';
    setTimeStamp(t);
    ble_npl_hw_exit_critical(0);

    return *this;
}

#endif /*(CONFIG_BT_ENABLED) */
#endif /* MAIN_NIMBLEATTVALUE_H_ */