Proper boundary checks & tests for them

[algorithm-bit-xs.git] / XS.xs

diff --git a/XS.xs b/XS.xs
index 3e6c839e892099d38902dbf91c1c70fe5c8c522c..bc8d89005e655c4a2187b2aaa8a0b95d8c2437b3 100644 (file)
--- 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;