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Improve ecma_utf8_string_to_number function (#2006)

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This patch extends the infinity and zero parsing of the convertible number by checking the normalized number exponent part.
This improvement prevents the engine's hanging while converting extreme big numbers.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu
This commit is contained in:
rerobika
2017-10-27 12:32:29 +02:00
committed by László Langó
parent 0bc4bb056d
commit 6dae81565c
2 changed files with 71 additions and 2 deletions
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jerry-core/ecma/base/ecma-helpers-conversion.c
+25 -2
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@@ -324,6 +324,20 @@
#define EPSILON 0.0000001
#if CONFIG_ECMA_NUMBER_TYPE == CONFIG_ECMA_NUMBER_FLOAT64
/**
* Number.MAX_VALUE and Number.MIN_VALUE exponent parts while using 64 bit float representation
*/
# define NUMBER_MAX_DECIMAL_EXPONENT 308
# define NUMBER_MIN_DECIMAL_EXPONENT -324
#elif CONFIG_ECMA_NUMBER_TYPE == CONFIG_ECMA_NUMBER_FLOAT32
/**
* Number.MAX_VALUE and Number.MIN_VALUE exponent parts while using 32 bit float representation
*/
# define NUMBER_MAX_DECIMAL_EXPONENT 38
# define NUMBER_MIN_DECIMAL_EXPONENT -45
#endif /* CONFIG_ECMA_NUMBER_TYPE == CONFIG_ECMA_NUMBER_FLOAT64 */
/**
* @}
*/
@@ -485,8 +499,7 @@ ecma_utf8_string_to_number (const lit_utf8_byte_t *str_p, /**< utf-8 string */
fraction_uint64 = fraction_uint64 * 10 + (uint32_t) digit_value;
digits++;
}
else if (e <= 100000) /* Limit the exponent, since large
* exponent is rounded to infinity anyway. */
else
{
e++;
}
@@ -581,6 +594,16 @@ ecma_utf8_string_to_number (const lit_utf8_byte_t *str_p, /**< utf-8 string */
}
e_in_lit = e_in_lit * 10 + digit_value;
int32_t e_check = e + (int32_t) digits - 1 + (e_in_lit_sign ? -e_in_lit : e_in_lit);
if (e_check > NUMBER_MAX_DECIMAL_EXPONENT)
{
return ecma_number_make_infinity (sign);
}
else if (e_check < NUMBER_MIN_DECIMAL_EXPONENT)
{
return sign ? -ECMA_NUMBER_ZERO : ECMA_NUMBER_ZERO;
}
begin_p++;
}