BLECharacteristic allow user set buffer

Author: hathach

libraries/Bluefruit52Lib/src/BLECharacteristic.cpp

@@ -53,6 +53,7 @@ void BLECharacteristic::_init(void)
   _attr_meta.read_perm = _attr_meta.write_perm = BLE_SECMODE_OPEN;
   _attr_meta.vlen = 1;
   _attr_meta.vloc = BLE_GATTS_VLOC_STACK;
+  _userbuf = NULL;
 
   _handles.value_handle     = BLE_GATT_HANDLE_INVALID;
   _handles.user_desc_handle = BLE_GATT_HANDLE_INVALID;
@@ -133,6 +134,14 @@ void BLECharacteristic::setFixedLen(uint16_t fixed_len)
   }
 }
 
+// Use application buffer instead of SD stack buffer
+void BLECharacteristic::setBuffer(void* buf, uint16_t bufsize)
+{
+  _max_len = bufsize;
+  _userbuf = buf;
+  _attr_meta.vloc = buf ? BLE_GATTS_VLOC_USER : BLE_GATTS_VLOC_STACK;
+}
+
 void BLECharacteristic::setPermission(BleSecurityMode read_perm, BleSecurityMode write_perm)
 {
   memcpy(&_attr_meta.read_perm , &read_perm, 1);
@@ -270,7 +279,7 @@ err_t BLECharacteristic::begin(void)
     .init_len  = (_attr_meta.vlen == 1) ? (uint16_t) 0 : _max_len,
     .init_offs = 0,
     .max_len   = _max_len,
-    .p_value   = NULL
+    .p_value   = _userbuf
   };
 
   VERIFY_STATUS( sd_ble_gatts_characteristic_add(BLE_GATT_HANDLE_INVALID, &char_md, &attr_char_value, &_handles) );

libraries/Bluefruit52Lib/src/BLECharacteristic.h

@@ -98,6 +98,7 @@ class BLECharacteristic
     void setPermission(BleSecurityMode read_perm, BleSecurityMode write_perm);
     void setMaxLen(uint16_t max_len);
     void setFixedLen(uint16_t fixed_len);
+    void setBuffer(void* buf, uint16_t bufsize);
 
     /*------------- Descriptors -------------*/
     void setUserDescriptor(const char* descriptor); // aka user descriptor
@@ -182,17 +183,12 @@ class BLECharacteristic
     virtual void _eventHandler(ble_evt_t* event);
 
   protected:
-    struct ATTR_PACKED {
-      uint8_t write           : 1;
-      uint8_t cccd_write      : 1;
-      uint8_t read_authorize  : 1;
-      uint8_t write_authorize : 1;
-    } _use_ada_cb;
-
     bool _is_temp;
     uint16_t _max_len;
     BLEService* _service; // pointer to parent's service
 
+    void* _userbuf;
+
     /*------------- Descriptors -------------*/
     const char* _usr_descriptor;
     struct ATTR_PACKED {
@@ -212,11 +208,18 @@ class BLECharacteristic
     }_long_wr;
 
     /*------------- Callback pointers -------------*/
-    read_authorize_cb_t       _rd_authorize_cb;
-    write_authorize_cb_t      _wr_authorize_cb;
+    struct ATTR_PACKED {
+      uint8_t write           : 1;
+      uint8_t cccd_write      : 1;
+      uint8_t read_authorize  : 1;
+      uint8_t write_authorize : 1;
+    } _use_ada_cb;
+
+    read_authorize_cb_t   _rd_authorize_cb;
+    write_authorize_cb_t  _wr_authorize_cb;
 
-    write_cb_t                _wr_cb;
-    write_cccd_cb_t           _cccd_wr_cb;
+    write_cb_t            _wr_cb;
+    write_cccd_cb_t       _cccd_wr_cb;
 
     /*------------- Internal Functions -------------*/
     void _init(void);