From 02b65a500f8dd89caf2b13ae066dbb4b7e1b5e3c Mon Sep 17 00:00:00 2001
From: Marius Gavrilescu <marius@ieval.ro>
Date: Sat, 17 Jun 2017 22:01:16 +0300
Subject: [PATCH] Proper boundary checks & tests for them

---
 XS.xs                | 27 +++++++++++----------------
 t/Algorithm-BIT-XS.t | 13 ++++++++++---
 2 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/XS.xs b/XS.xs
index 3e6c839..bc8d890 100644
--- a/XS.xs
+++ b/XS.xs
@@ -5,6 +5,11 @@
 
 #include "ppport.h"
 
+#define CHECK_INDEX(idx, min, max, ret) if(idx < min || idx > max) {	\
+		croak("Index not in range [" IVdf "," IVdf "]", (IV)(min), (IV)(max)); \
+		return ret;														\
+	}
+
 typedef struct {
 	IV n;
 	IV* t;
@@ -29,10 +34,7 @@ void bit_free(bit *b) {
 }
 
 IV bit_query(bit *b, IV idx) {
-	if(idx > b->n || idx < 1){
-		croak("Index not in range [1," IVdf "]", b->n);
-		return 0;
-	}
+	CHECK_INDEX(idx, 0, b->n - 1, 0);
 	IV ret = 0;
 	while(idx)
 		ret += b->t[idx], idx -= idx & -idx;
@@ -40,10 +42,7 @@ IV bit_query(bit *b, IV idx) {
 }
 
 void bit_update(bit *b, IV idx, IV value) {
-	if(idx > b->n || idx < 1){
-		croak("Index not in range [1," IVdf "]", b->n);
-		return;
-	}
+	CHECK_INDEX(idx, 0, b->n - 1, );
 	while(idx < b->n)
 		b->t[idx] += value, idx += idx & -idx;
 }
@@ -77,6 +76,8 @@ void bit2d_free(bit2d *b) {
 }
 
 IV bit2d_query(bit2d *b, IV i1, IV i2) {
+	CHECK_INDEX(i1, 1, b->n - 1, 0);
+	CHECK_INDEX(i2, 1, b->m - 1, 0);
 	if(i1 > b->n || i1 < 1) {
 		croak("Index 1 not in range [1," IVdf "]", b->n);
 		return 0;
@@ -96,14 +97,8 @@ IV bit2d_query(bit2d *b, IV i1, IV i2) {
 }
 
 void bit2d_update(bit2d *b, IV i1, IV i2, IV value) {
-	if(i1 > b->n || i1 < 1) {
-		croak("Index 1 not in range [1," IVdf "]", b->n);
-		return;
-	}
-	if(i2 > b->m || i2 < 1) {
-		croak("Index 2 not in range [1," IVdf "]", b->m);
-		return;
-	}
+	CHECK_INDEX(i1, 1, b->n - 1, );
+	CHECK_INDEX(i2, 1, b->m - 1, );
 	IV i2c = i2;
 	while(i1 < b->n) {
 		i2 = i2c;
diff --git a/t/Algorithm-BIT-XS.t b/t/Algorithm-BIT-XS.t
index c2ee47a..914792a 100644
--- a/t/Algorithm-BIT-XS.t
+++ b/t/Algorithm-BIT-XS.t
@@ -2,11 +2,13 @@
 use strict;
 use warnings;
 
-use Test::More tests => 17;
+use Test::More tests => 24;
 BEGIN { use_ok('Algorithm::BIT::XS') };
 BEGIN { use_ok('Algorithm::BIT2D::XS') };
 
-my $bit = Algorithm::BIT::XS->new(100);
+my $bit = Algorithm::BIT::XS->new(25);
+ok !eval{$bit->query(26); 1}, 'query(26) fails';
+ok !eval{$bit->update(26, 5); 1}, 'update(26, 5) fails';
 is $bit->query(5), 0;
 $bit->update(4, 2);
 $bit->update(5, 3);
@@ -14,6 +16,7 @@ is $bit->query(3), 0;
 is $bit->query(4), 2;
 is $bit->query(5), 5;
 is $bit->query(6), 5;
+is $bit->query(0), 0;
 
 $bit->update(5, -3);
 is $bit->query(5), 2;
@@ -32,7 +35,11 @@ is $bit->query(15), 0;
 is $bit->query(16), 10;
 
 
-my $bit2d = Algorithm::BIT2D::XS->new(100, 50);
+my $bit2d = Algorithm::BIT2D::XS->new(10, 5);
+ok !eval{$bit2d->query(11, 5); 1}, 'query(11, 5) fails';
+ok !eval{$bit2d->query(10, 6); 1}, 'query(10, 6) fails';
+ok !eval{$bit2d->update(11, 5, 2); 1}, 'update(11, 5, 2) fails';
+ok !eval{$bit2d->update(10, 6, 2); 1}, 'update(10, 6, 2) fails';
 is $bit2d->query(5, 5), 0;
 $bit2d->update(4, 4, 2);
 $bit2d->update(5, 1, 3);
-- 
2.30.2