Fix count variable calculation in typedarray copyWithin

szilagyiadam · szilagyiadam · commit 5bb3f0faca94 · 2019-09-30T14:46:10.000+02:00
Fixes #3130 JerryScript-DCO-1.0-Signed-off-by: Adam Szilagyi aszilagy@inf.u-szeged.hu
diff --git a/jerry-core/ecma/builtin-objects/typedarray/ecma-builtin-typedarray-prototype.c b/jerry-core/ecma/builtin-objects/typedarray/ecma-builtin-typedarray-prototype.c
@@ -1887,16 +1887,16 @@ ecma_builtin_typedarray_prototype_copy_within (ecma_value_t this_arg, /**< this
     }
   }
 
-  int32_t distance = (int32_t) (end - start);
-  int32_t offset = (int32_t) (length - target);
-  int32_t count = JERRY_MIN (distance, offset);
-
   if (target >= length || end == 0 || start >= end)
   {
     return ecma_copy_value (this_arg);
   }
   else
   {
+    uint32_t distance = end - start;
+    uint32_t offset = length - target;
+    uint32_t count = JERRY_MIN (distance, offset);
+
     memmove (typedarray_buffer_p + (target * element_size),
              typedarray_buffer_p + (start * element_size),
              (size_t) (count * element_size));

Original file line number	Diff line number	Diff line change
`@@ -1887,16 +1887,16 @@ ecma_builtin_typedarray_prototype_copy_within (ecma_value_t this_arg, /**< this`
`1887`	`1887`	`}`
`1888`	`1888`	`}`
`1889`	`1889`
`1890`		`- int32_t distance = (int32_t) (end - start);`
`1891`		`- int32_t offset = (int32_t) (length - target);`
`1892`		`- int32_t count = JERRY_MIN (distance, offset);`
`1893`		`-`
`1894`	`1890`	`if (target >= length \|\| end == 0 \|\| start >= end)`
`1895`	`1891`	`{`
`1896`	`1892`	`return ecma_copy_value (this_arg);`
`1897`	`1893`	`}`
`1898`	`1894`	`else`
`1899`	`1895`	`{`
	`1896`	`+ uint32_t distance = end - start;`
	`1897`	`+ uint32_t offset = length - target;`
	`1898`	`+ uint32_t count = JERRY_MIN (distance, offset);`
	`1899`	`+`
`1900`	`1900`	`memmove (typedarray_buffer_p + (target * element_size),`
`1901`	`1901`	`typedarray_buffer_p + (start * element_size),`
`1902`	`1902`	`(size_t) (count * element_size));`