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Fixing ecma_builtin_number_prototype_helper_round. (#1362)

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"ecma_builtin_number_prototype_helper_round" is used by following
functions:
* ecma_builtin_number_prototype_object_to_fixed
* ecma_builtin_number_prototype_object_to_exponential
* ecma_builtin_number_prototype_object_to_precision

The current implementation does not support currying numbers and will
produce illegal digit for some test cases. For example, the result of
"0.95.toFixed(1)" is "0.:".

This patch fixs the issue, however the implementation of "toFixed" is
still problematic, at least not meet section 15.7.4.5 8.a of the
specification. The related test case is:

* assert((0.995).toFixed(2) === "0.99");
* assert((9.995).toFixed(2) === "9.99");

Reference:
* http://www.ecma-international.org/ecma-262/5.1/#sec-15.7.4.5

JerryScript-DCO-1.0-Signed-off-by: Yanhui Shen shen.elf@gmail.com
This commit is contained in:
Yanhui Shen 2016-09-20 19:13:50 +08:00 committed by László Langó
parent 7b7d86f5fd
commit a9d6978e4b
2 changed files with 34 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

35
jerry-core/ecma/builtin-objects/ecma-builtin-number-prototype.c
View File

@ -135,7 +135,8 @@ static inline lit_utf8_size_t __attr_always_inline___
ecma_builtin_number_prototype_helper_round (lit_utf8_byte_t *digits_p, /**< [in,out] number as a string in decimal
* form */
lit_utf8_size_t num_digits, /**< length of the string representation */
int32_t round_num) /**< number of digits to keep */
int32_t round_num, /**< number of digits to keep */
int32_t *exponent_p) /**< [in, out] decimal exponent */
{
if (round_num < 1)
{
@ -149,8 +150,29 @@ ecma_builtin_number_prototype_helper_round (lit_utf8_byte_t *digits_p, /**< [in,
if (digits_p[round_num] >= '5')
{
digits_p[round_num - 1]++;
digits_p[round_num] = '0';
int i = 1;
/* Handle curry number. */
for (; i < (int) num_digits; i++)
{
if (++digits_p[round_num - i] <= '9')
{
break;
}
digits_p[round_num - i] = '0';
}
/* Prepend highest digit */
if (i >= (int) num_digits)
{
memmove (digits_p + 1, digits_p, num_digits);
digits_p[0] = '1';
*exponent_p += 1;
}
}
return (lit_utf8_size_t) round_num;
} /* ecma_builtin_number_prototype_helper_round */
@ -535,7 +557,10 @@ ecma_builtin_number_prototype_object_to_fixed (ecma_value_t this_arg, /**< this
/* 1. */
int32_t frac_digits = ecma_number_to_int32 (arg_num);
num_digits = ecma_builtin_number_prototype_helper_round (digits, num_digits, exponent + frac_digits);
num_digits = ecma_builtin_number_prototype_helper_round (digits,
num_digits,
exponent + frac_digits,
&exponent);
/* Buffer that is used to construct the string. */
int buffer_size = (exponent > 0) ? exponent + frac_digits + 2 : frac_digits + 3;
@ -670,7 +695,7 @@ ecma_builtin_number_prototype_object_to_exponential (ecma_value_t this_arg, /**<
frac_digits = ecma_number_to_int32 (arg_num);
}
num_digits = ecma_builtin_number_prototype_helper_round (digits, num_digits, frac_digits + 1);
num_digits = ecma_builtin_number_prototype_helper_round (digits, num_digits, frac_digits + 1, &exponent);
/* frac_digits + 2 characters for number, 5 characters for exponent, 1 for \0. */
int buffer_size = frac_digits + 2 + 5 + 1;
@ -814,7 +839,7 @@ ecma_builtin_number_prototype_object_to_precision (ecma_value_t this_arg, /**< t
int32_t precision = ecma_number_to_int32 (arg_num);
num_digits = ecma_builtin_number_prototype_helper_round (digits, num_digits, precision);
num_digits = ecma_builtin_number_prototype_helper_round (digits, num_digits, precision, &exponent);
int buffer_size;
if (exponent < -5 || exponent > precision)

4
tests/jerry/number-prototype-to-fixed.js
View File

@ -37,6 +37,10 @@ assert((-0.0).toFixed(1) === "-0.0");
assert((123456789012345678901.0).toFixed(20) === "123456789012345680000.00000000000000000000");
assert((123.56).toFixed(NaN) === "124");
assert((123.56).toFixed(-0.9) === "124");
assert((0.095).toFixed(2) === "0.10");
//assert((0.995).toFixed(2) === "0.99");
//assert((9.995).toFixed(2) === "9.99");
assert((99.995).toFixed(2) === "100.00");
try {
Number.prototype.toExponential.call(new Object());