Merge pull request #2200 from cremno/add-functions-for-safe-addition-and-subtraction

Add functions for safe addition and subtraction

1 files changed, 7 insertions, 18 deletions

diff --git a/src/vm.c b/src/vm.c
index 0e3c0a81e..ae19db0b6 100644
--- a/src/vm.c
+++ b/src/vm.c
@@ -12,6 +12,7 @@
 #include "mruby/class.h"
 #include "mruby/hash.h"
 #include "mruby/irep.h"
+#include "mruby/numeric.h"
 #include "mruby/proc.h"
 #include "mruby/range.h"
 #include "mruby/string.h"
@@ -1610,12 +1611,7 @@ RETRY_TRY_BLOCK:
 
           x = mrb_fixnum(regs_a[0]);
           y = mrb_fixnum(regs_a[1]);
-          z = x + y;
-#ifdef MRB_WORD_BOXING
-          z = (z << MRB_FIXNUM_SHIFT) / (1 << MRB_FIXNUM_SHIFT);
-#endif
-          if ((x < 0) != (z < 0) && ((x < 0) ^ (y < 0)) == 0) {
-            /* integer overflow */
+          if (mrb_int_add_overflow(x, y, &z)) {
             SET_FLT_VALUE(mrb, regs_a[0], (mrb_float)x + (mrb_float)y);
             break;
           }
@@ -1673,12 +1669,7 @@ RETRY_TRY_BLOCK:
 
           x = mrb_fixnum(regs[a]);
           y = mrb_fixnum(regs[a+1]);
-          z = x - y;
-#ifdef MRB_WORD_BOXING
-          z = (z << MRB_FIXNUM_SHIFT) / (1 << MRB_FIXNUM_SHIFT);
-#endif
-          if (((x < 0) ^ (y < 0)) != 0 && (x < 0) != (z < 0)) {
-            /* integer overflow */
+          if (mrb_int_sub_overflow(x, y, &z)) {
             SET_FLT_VALUE(mrb, regs[a], (mrb_float)x - (mrb_float)y);
             break;
           }
@@ -1842,10 +1833,9 @@ RETRY_TRY_BLOCK:
         {
           mrb_int x = regs[a].attr_i;
           mrb_int y = GETARG_C(i);
-          mrb_int z = x + y;
+          mrb_int z;
 
-          if (((x < 0) ^ (y < 0)) == 0 && (x < 0) != (z < 0)) {
-            /* integer overflow */
+          if (mrb_int_add_overflow(x, y, &z)) {
             SET_FLT_VALUE(mrb, regs[a], (mrb_float)x + (mrb_float)y);
             break;
           }
@@ -1881,10 +1871,9 @@ RETRY_TRY_BLOCK:
         {
           mrb_int x = regs_a[0].attr_i;
           mrb_int y = GETARG_C(i);
-          mrb_int z = x - y;
+          mrb_int z;
 
-          if ((x < 0) != (z < 0) && ((x < 0) ^ (y < 0)) != 0) {
-            /* integer overflow */
+          if (mrb_int_sub_overflow(x, y, &z)) {
             SET_FLT_VALUE(mrb, regs_a[0], (mrb_float)x - (mrb_float)y);
           }
           else {