# HG changeset patch
# User Chris Cannam
# Date 1512984520 0
# Node ID 622d193a00dc1dd5caf50bb242d840508ac1892c
# Parent  9ae40c7aecdfd605099504ed5a9fc0179e96cfc1
Rework canonicalisation so as to avoid theoretical possibility of integer overflow

diff -r 9ae40c7aecdf -r 622d193a00dc base/RealTimeSV.cpp
--- a/base/RealTimeSV.cpp	Thu Dec 07 13:33:30 2017 +0000
+++ b/base/RealTimeSV.cpp	Mon Dec 11 09:28:40 2017 +0000
@@ -19,6 +19,7 @@
 */
 
 #include <iostream>
+#include <limits.h>
 
 #include <cstdlib>
 #include <sstream>
@@ -43,16 +44,10 @@
 RealTime::RealTime(int s, int n) :
     sec(s), nsec(n)
 {
-    if (sec == 0) {
-	while (nsec <= -ONE_BILLION) { nsec += ONE_BILLION; --sec; }
-	while (nsec >=  ONE_BILLION) { nsec -= ONE_BILLION; ++sec; }
-    } else if (sec < 0) {
-	while (nsec <= -ONE_BILLION) { nsec += ONE_BILLION; --sec; }
-	while (nsec > 0 && sec < 0)  { nsec -= ONE_BILLION; ++sec; }
-    } else { 
-	while (nsec >=  ONE_BILLION) { nsec -= ONE_BILLION; ++sec; }
-	while (nsec < 0 && sec > 0)  { nsec += ONE_BILLION; --sec; }
-    }
+    while (nsec <= -ONE_BILLION && sec > INT_MIN) { nsec += ONE_BILLION; --sec; }
+    while (nsec >=  ONE_BILLION && sec < INT_MAX) { nsec -= ONE_BILLION; ++sec; }
+    while (nsec > 0 && sec < 0) { nsec -= ONE_BILLION; ++sec; }
+    while (nsec < 0 && sec > 0) { nsec += ONE_BILLION; --sec; }
 }
 
 RealTime
diff -r 9ae40c7aecdf -r 622d193a00dc base/test/TestOurRealTime.h
--- a/base/test/TestOurRealTime.h	Thu Dec 07 13:33:30 2017 +0000
+++ b/base/test/TestOurRealTime.h	Mon Dec 11 09:28:40 2017 +0000
@@ -70,6 +70,11 @@
 
         QCOMPARE(RealTime(-2, ONE_BILLION*2), RealTime(0, 0));
         QCOMPARE(RealTime(-2, ONE_BILLION/2), RealTime(-1, -ONE_BILLION/2));
+
+        QCOMPARE(RealTime(1, -ONE_BILLION/2).sec, 0);
+        QCOMPARE(RealTime(1, -ONE_BILLION/2).nsec, ONE_BILLION/2);
+        QCOMPARE(RealTime(-1, ONE_BILLION/2).sec, 0);
+        QCOMPARE(RealTime(-1, ONE_BILLION/2).nsec, -ONE_BILLION/2);
         
         QCOMPARE(RealTime(0, 1).sec, 0);
         QCOMPARE(RealTime(0, 1).nsec, 1);