Improved comments.

2 files changed, 6 insertions, 4 deletions

diff --git a/main.c b/main.c
index d1a66fc..5112448 100644
--- a/main.c
+++ b/main.c
@@ -54,7 +54,7 @@ typedef struct {
 typedef struct {
 	task_st		*tasks;
 	size_t		count;			// Will always be equal or less than capacity.
-	size_t		capacity;		// Limited to PTRDIFF_MAX.
+	size_t		capacity;		// Will always be equal or less than PTRDIFF_MAX (see MAX_DATABASE_TASKS).
 	ptrdiff_t	active_task;	// Will always be less than capacity/count.
 	ptrdiff_t	selected_task;	// Will always be less than capacity/count.
 	int64_t		modified_on;
@@ -288,8 +288,9 @@ bool create_task(database_st *db, task_st **task) {
 	// If necessary, expand database capacity.
 	size_t current_capacity = db->capacity;
 	if((db->count + 1) > current_capacity) {
-		size_t new_capacity = current_capacity == 0 ? 2 :
-			current_capacity > MAX_DATABASE_TASKS >> 1 ? MAX_DATABASE_TASKS :
+		size_t new_capacity =
+			current_capacity == 0 ? 2 :
+			current_capacity > (MAX_DATABASE_TASKS >> 1) ? MAX_DATABASE_TASKS :
 			current_capacity << 1;
 		
 		task_st *new_tasks = realloc(db->tasks, new_capacity * SIZEOF_TASK_ST);
diff --git a/readme.md b/readme.md
index 5c76d63..264c790 100644
--- a/readme.md
+++ b/readme.md
@@ -41,7 +41,8 @@ Task Time Tracker
 - [x] Check if next/previous is safe against overflows/underflows using https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html
 - [x] Confirm delete_task operation by show confirmation message on selected line (horizontally centered).
 - [x] Check totals update speedup using https://gcc.gnu.org/onlinedocs/gcc/Integer-Overflow-Builtins.html
-	- For 1M entries, generic C code runs in 12.0ms while special approaches using builtins or SIMD takes around 9.5ms. Not worth the effort.
+	- For 1M entries, generic C code runs in 12.0ms while special approaches using builtins or SIMD takes around 9.5ms.
+	- Used optimization described [here](https://stackoverflow.com/questions/17580118/signed-saturated-add-of-64-bit-ints).
 - [x] Allow to jump to specific task by index number using key `g` and `G`;
 - [x] Move task to (using task_t tmp_task + memcpy) using key `m` and `M`;
 - [x] Rethink keys;