From 7b6395ea5894399fcd0796038fd033a75749a791 Mon Sep 17 00:00:00 2001
From: Matthias Ringwald <matthias@ringwald.ch>
Date: Tue, 10 May 2016 10:06:29 +0200
Subject: [PATCH] examples: fix chunk len calculation in att_read_callback for
 le_couner and spp_and_le_couner

---
 example/le_counter.c         | 14 +++++++++++---
 example/spp_and_le_counter.c | 28 +++++++++++++++++++++-------
 2 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/example/le_counter.c b/example/le_counter.c
index f2912c051..b918b632a 100644
--- a/example/le_counter.c
+++ b/example/le_counter.c
@@ -117,6 +117,9 @@ static void le_counter_setup(void){
     heartbeat.process = &heartbeat_handler;
     btstack_run_loop_set_timer(&heartbeat, HEARTBEAT_PERIOD_MS);
     btstack_run_loop_add_timer(&heartbeat);
+
+    // beat once
+    beat();
 }
 /* LISTING_END */
 
@@ -189,13 +192,18 @@ static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *pack
 // - if buffer != NULL, copy data and return number bytes copied
 // @param offset defines start of attribute value
 static uint16_t att_read_callback(hci_con_handle_t connection_handle, uint16_t att_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size){
+    uint16_t size = 0;
     if (att_handle == ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE){
         if (buffer){
-            memcpy(buffer, &counter_string[offset], counter_string_len - offset);
+            // size is bound by actual value chunk and provided buffer
+            size = btstack_min(counter_string_len - offset, buffer_size);
+            memcpy(buffer, &counter_string[offset], size);
+        } else {
+            // size is only bound by actual value chunk
+            size = counter_string_len - offset;
         }
-        return counter_string_len - offset;
     }
-    return 0;
+    return size;
 }
 /* LISTING_END */
 
diff --git a/example/spp_and_le_counter.c b/example/spp_and_le_counter.c
index 1bdd6c8c6..8f51727c9 100644
--- a/example/spp_and_le_counter.c
+++ b/example/spp_and_le_counter.c
@@ -176,14 +176,18 @@ static void packet_handler (uint8_t packet_type, uint16_t channel, uint8_t *pack
 // - if buffer != NULL, copy data and return number bytes copied
 // @param offset defines start of attribute value
 static uint16_t att_read_callback(hci_con_handle_t con_handle, uint16_t att_handle, uint16_t offset, uint8_t * buffer, uint16_t buffer_size){
+    uint16_t size = 0;
     if (att_handle == ATT_CHARACTERISTIC_0000FF11_0000_1000_8000_00805F9B34FB_01_VALUE_HANDLE){
         if (buffer){
-            log_info("att_read_callback for Characteristic *FF11*, value %s", counter_string);
-            memcpy(buffer, &counter_string[offset], counter_string_len - offset);
+            // size is bound by actual value chunk and provided buffer
+            size = btstack_min(counter_string_len - offset, buffer_size);
+            memcpy(buffer, &counter_string[offset], size);
+        } else {
+            // size is only bound by actual value chunk
+            size = counter_string_len - offset;
         }
-        return counter_string_len - offset;
     }
-    return 0;
+    return size;
 }
 
 // write requests
@@ -207,6 +211,12 @@ static int att_write_callback(hci_con_handle_t con_handle, uint16_t att_handle,
     }
 }
 
+static void beat(void){
+    counter++;
+    counter_string_len = sprintf(counter_string, "BTstack counter %04u", counter);
+    puts(counter_string);
+}
+
 /*
  * @section Heartbeat Handler
  * 
@@ -217,9 +227,9 @@ static int att_write_callback(hci_con_handle_t con_handle, uint16_t att_handle,
  /* LISTING_START(heartbeat): Combined Heartbeat handler */
 static void heartbeat_handler(struct btstack_timer_source *ts){
 
-    counter++;
-    counter_string_len = sprintf(counter_string, "BTstack counter %04u\n", counter);
-    // log_info("%s", counter_string);
+    if (rfcomm_channel_id || le_notification_enabled) {
+        beat();
+    }
 
     if (rfcomm_channel_id){
         rfcomm_request_can_send_now_event(rfcomm_channel_id);
@@ -228,6 +238,7 @@ static void heartbeat_handler(struct btstack_timer_source *ts){
     if (le_notification_enabled) {
         att_server_request_can_send_now_event(att_con_handle);
     }
+
     btstack_run_loop_set_timer(ts, HEARTBEAT_PERIOD_MS);
     btstack_run_loop_add_timer(ts);
 } 
@@ -288,6 +299,9 @@ int btstack_main(void)
     gap_advertisements_set_data(adv_data_len, (uint8_t*) adv_data);
     gap_advertisements_enable(1);
 
+    // beat once
+    beat();
+
     // turn on!
 	hci_power_control(HCI_POWER_ON);