From 1759eef334df7996e339029f62b77c49e72a31d4 Mon Sep 17 00:00:00 2001
From: loikki <loic.hausammann@protonmail.ch>
Date: Wed, 5 Jun 2019 18:06:07 +0200
Subject: [PATCH] Logger: Implement a binary search for the time array
---
logger/logger_time.c | 28 +++++++++++++++++++---------
1 file changed, 19 insertions(+), 9 deletions(-)
diff --git a/logger/logger_time.c b/logger/logger_time.c
index ef5bc04451..829b87a1e1 100644
--- a/logger/logger_time.c
+++ b/logger/logger_time.c
@@ -224,21 +224,31 @@ size_t time_array_get_index(const struct time_array *t, const size_t offset) {
#ifdef SWIFT_DEBUG_CHECKS
if (!t) error("NULL pointer.");
- if (offset < t->records[0].offset || offset > t->records[t->size].offset)
+ if (offset < t->records[0].offset || offset > t->records[t->size - 1].offset)
error("Offset outside of range.");
#endif
- /* Find the time_array with the correct offset. */
- for (size_t i = 1; i < t->size; i++) {
- if (offset < t->records[i].offset) {
- return i - 1;
+ /* left will contain the index at the end of the loop */
+ size_t left = 0;
+ size_t right = t->size - 1;
+
+ /* Find the time_array with the correct offset through a bisection method. */
+ while (left <= right) {
+ size_t center = (left + right) / 2;
+ const size_t offset_center = t->records[center].offset;
+
+ if (offset > offset_center) {
+ left = center + 1;
+ }
+ else if (offset < offset_center) {
+ right = center - 1;
+ }
+ else {
+ return center;
}
-
- else if (offset == t->records[i].offset)
- return i;
}
- error("Unable to find the required offset.");
+ return right;
}
/**
--
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