Optimize number-to-string conversion
* Make constants static in `ecma_number_to_utf8_string`. * Make `ecma_number_to_utf8_string` use early returns, and rewrite its self-recursion in case of negative numbers. * Make the stringification of decimal exponent in `ecma_number_to_utf8_string` use `ecma_uint32_to_utf8_string`. * Changed ERROL0 dtoa implementation to use the `double` type instead of `ecma_number_t`. Thus, even is `ecma_number_t` is 32 bit wide, the algorithm works the same. * Changed `ecma_number_to_decimal` to use the ERROL0 dtoa algorithm for 32-bit floats as well. * Changed `ecma_number_to_decimal` to generate the decimal string representation of the mantissa instead of an `uint64_t` number. * Changed `ecma_number_to_utf8_string` to make use of the already available string representation of the mantissa, generated now by `ecma_number_to_decimal`. * Changed `ecma_number_to_utf8_string` not to use static arrays and variables for digit, "e", etc. generation. * Changed all `Number.prototype.toXXX` implementations and the `ecma_builtin_number_prototype_helper_round` helper to make use of the already available string representation of the mantissa, generated now by `ecma_number_to_decimal`. * Factored out the common stringification parts of all `Number.prototype.toXXX` implementations into a new helper `ecma_builtin_number_prototype_helper_to_string`. JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu
This commit is contained in:
Akos Kiss
committed by
Zoltan Herczeg
Zoltan Herczeg
parent
65542549af
commit
30fd549e7f
@@ -919,14 +919,13 @@ ecma_number_to_int32 (ecma_number_t num) /**< ecma-number */
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*
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* Note:
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* The calculated values correspond to s, n, k parameters in ECMA-262 v5, 9.8.1, item 5:
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* - s represents digits of the number;
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* - k is the number of digits;
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* - n is the decimal exponent.
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* - parameter out_digits_p corresponds to s, the digits of the number;
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* - parameter out_decimal_exp_p corresponds to n, the decimal exponent;
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* - return value corresponds to k, the number of digits.
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*/
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void
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lit_utf8_size_t
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ecma_number_to_decimal (ecma_number_t num, /**< ecma-number */
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uint64_t *out_digits_p, /**< [out] digits */
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int32_t *out_digits_num_p, /**< [out] number of digits */
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lit_utf8_byte_t *out_digits_p, /**< [out] buffer to fill with digits */
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int32_t *out_decimal_exp_p) /**< [out] decimal exponent */
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{
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JERRY_ASSERT (!ecma_number_is_nan (num));
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@@ -934,130 +933,7 @@ ecma_number_to_decimal (ecma_number_t num, /**< ecma-number */
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JERRY_ASSERT (!ecma_number_is_infinity (num));
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JERRY_ASSERT (!ecma_number_is_negative (num));
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#if CONFIG_ECMA_NUMBER_TYPE == CONFIG_ECMA_NUMBER_FLOAT64
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*out_digits_p = ecma_errol0_dtoa (num, out_digits_num_p, out_decimal_exp_p);
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#elif CONFIG_ECMA_NUMBER_TYPE == CONFIG_ECMA_NUMBER_FLOAT32
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/* Less precise conversion */
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uint64_t fraction_uint64;
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uint32_t fraction;
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int32_t exponent;
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int32_t dot_shift;
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int32_t decimal_exp = 0;
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dot_shift = ecma_number_get_fraction_and_exponent (num, &fraction_uint64, &exponent);
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fraction = (uint32_t) fraction_uint64;
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JERRY_ASSERT (fraction == fraction_uint64);
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if (exponent != 0)
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{
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ecma_number_t t = 1.0f;
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bool do_divide;
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if (exponent < 0)
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{
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do_divide = true;
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while (exponent <= 0)
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{
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t *= 2.0f;
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exponent++;
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if (t >= 10.0f)
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{
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t /= 10.0f;
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decimal_exp--;
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}
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JERRY_ASSERT (t < 10.0f);
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}
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while (t > 1.0f)
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{
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exponent--;
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t /= 2.0f;
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}
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}
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else
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{
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do_divide = false;
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while (exponent >= 0)
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{
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t *= 2.0f;
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exponent--;
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if (t >= 10.0f)
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{
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t /= 10.0f;
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decimal_exp++;
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}
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JERRY_ASSERT (t < 10.0f);
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}
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while (t > 2.0f)
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{
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exponent++;
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t /= 2.0f;
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}
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}
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if (do_divide)
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{
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fraction = (uint32_t) ((ecma_number_t) fraction / t);
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}
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else
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{
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fraction = (uint32_t) ((ecma_number_t) fraction * t);
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}
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}
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uint32_t s;
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int32_t n;
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int32_t k;
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if (exponent > 0)
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{
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fraction <<= exponent;
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}
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else
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{
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fraction >>= -exponent;
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}
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const int32_t int_part_shift = dot_shift;
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const uint32_t frac_part_mask = ((((uint32_t) 1) << int_part_shift) - 1);
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uint32_t int_part = fraction >> int_part_shift;
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uint32_t frac_part = fraction & frac_part_mask;
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s = int_part;
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k = 1;
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n = decimal_exp + 1;
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JERRY_ASSERT (int_part < 10);
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while (k < ECMA_NUMBER_MAX_DIGITS
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&& frac_part != 0)
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{
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frac_part *= 10;
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uint32_t new_frac_part = frac_part & frac_part_mask;
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uint32_t digit = (frac_part - new_frac_part) >> int_part_shift;
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s = s * 10 + digit;
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k++;
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frac_part = new_frac_part;
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}
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JERRY_ASSERT (k > 0);
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*out_digits_p = s;
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*out_digits_num_p = k;
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*out_decimal_exp_p = n;
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#endif /* CONFIG_ECMA_NUMBER_TYPE == CONFIG_ECMA_NUMBER_FLOAT64 */
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return ecma_errol0_dtoa ((double) num, out_digits_p, out_decimal_exp_p);
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} /* ecma_number_to_decimal */
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/**
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@@ -1074,204 +950,119 @@ ecma_number_to_utf8_string (ecma_number_t num, /**< ecma-number */
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lit_utf8_byte_t *buffer_p, /**< buffer for utf-8 string */
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lit_utf8_size_t buffer_size) /**< size of buffer */
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{
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const lit_utf8_byte_t digits[10] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
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const lit_utf8_byte_t e_chars[2] = { 'e', 'E' };
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const lit_utf8_byte_t plus_char = '+';
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const lit_utf8_byte_t minus_char = '-';
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const lit_utf8_byte_t dot_char = '.';
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lit_utf8_size_t size;
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lit_utf8_byte_t *dst_p;
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if (ecma_number_is_nan (num))
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{
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// 1.
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lit_copy_magic_string_to_buffer (LIT_MAGIC_STRING_NAN, buffer_p, buffer_size);
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size = lit_get_magic_string_size (LIT_MAGIC_STRING_NAN);
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dst_p = lit_copy_magic_string_to_buffer (LIT_MAGIC_STRING_NAN, buffer_p, buffer_size);
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return (lit_utf8_size_t) (dst_p - buffer_p);
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}
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if (ecma_number_is_zero (num))
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{
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// 2.
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*buffer_p = LIT_CHAR_0;
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JERRY_ASSERT (1 <= buffer_size);
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return 1;
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}
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dst_p = buffer_p;
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if (ecma_number_is_negative (num))
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{
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// 3.
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*dst_p++ = LIT_CHAR_MINUS;
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num = ecma_number_negate (num);
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}
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if (ecma_number_is_infinity (num))
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{
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// 4.
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dst_p = lit_copy_magic_string_to_buffer (LIT_MAGIC_STRING_INFINITY_UL, dst_p,
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(lit_utf8_size_t) (buffer_p + buffer_size - dst_p));
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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return (lit_utf8_size_t) (dst_p - buffer_p);
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}
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JERRY_ASSERT (ecma_number_get_next (ecma_number_get_prev (num)) == num);
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// 5.
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uint32_t num_uint32 = ecma_number_to_uint32 (num);
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if (((ecma_number_t) num_uint32) == num)
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{
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dst_p += ecma_uint32_to_utf8_string (num_uint32, dst_p, (lit_utf8_size_t) (buffer_p + buffer_size - dst_p));
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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return (lit_utf8_size_t) (dst_p - buffer_p);
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}
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/* decimal exponent */
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int32_t n;
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/* number of digits in mantissa */
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int32_t k;
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k = (int32_t) ecma_number_to_decimal (num, dst_p, &n);
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if (k <= n && n <= 21)
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{
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// 6.
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dst_p += k;
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memset (dst_p, LIT_CHAR_0, (size_t) (n - k));
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dst_p += n - k;
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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return (lit_utf8_size_t) (dst_p - buffer_p);
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}
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if (0 < n && n <= 21)
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{
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// 7.
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memmove (dst_p + n + 1, dst_p + n, (size_t) (k - n));
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*(dst_p + n) = LIT_CHAR_DOT;
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dst_p += k + 1;
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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return (lit_utf8_size_t) (dst_p - buffer_p);
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}
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if (-6 < n && n <= 0)
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{
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// 8.
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memmove (dst_p + 2 - n, dst_p, (size_t) k);
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memset (dst_p + 2, LIT_CHAR_0, (size_t) -n);
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*dst_p = LIT_CHAR_0;
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*(dst_p + 1) = LIT_CHAR_DOT;
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dst_p += k - n + 2;
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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return (lit_utf8_size_t) (dst_p - buffer_p);
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}
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if (k == 1)
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{
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// 9.
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dst_p++;
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}
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else
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{
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lit_utf8_byte_t *dst_p = buffer_p;
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if (ecma_number_is_zero (num))
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{
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// 2.
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*dst_p++ = digits[0];
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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size = (lit_utf8_size_t) (dst_p - buffer_p);
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}
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else if (ecma_number_is_negative (num))
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{
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// 3.
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*dst_p++ = minus_char;
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lit_utf8_size_t new_buffer_size = (lit_utf8_size_t) ((buffer_p + buffer_size) - dst_p);
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size = 1 + ecma_number_to_utf8_string (ecma_number_negate (num), dst_p, new_buffer_size);
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}
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else if (ecma_number_is_infinity (num))
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{
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// 4.
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dst_p = lit_copy_magic_string_to_buffer (LIT_MAGIC_STRING_INFINITY_UL, buffer_p, buffer_size);
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size = (lit_utf8_size_t) (dst_p - buffer_p);
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}
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else
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{
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ecma_number_t p = ecma_number_get_prev (num);
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ecma_number_t q = ecma_number_get_next (p);
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JERRY_ASSERT (q == num);
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// 5.
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uint32_t num_uint32 = ecma_number_to_uint32 (num);
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if (((ecma_number_t) num_uint32) == num)
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{
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size = ecma_uint32_to_utf8_string (num_uint32, dst_p, buffer_size);
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}
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else
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{
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/* mantissa */
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uint64_t s;
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/* decimal exponent */
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int32_t n;
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/* number of digits in k */
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int32_t k;
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ecma_number_to_decimal (num, &s, &k, &n);
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// 6.
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if (k <= n && n <= 21)
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{
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dst_p += n;
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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size = (lit_utf8_size_t) (dst_p - buffer_p);
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for (int32_t i = 0; i < n - k; i++)
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{
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*--dst_p = digits[0];
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}
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for (int32_t i = 0; i < k; i++)
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{
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*--dst_p = digits[s % 10];
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s /= 10;
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}
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}
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else if (0 < n && n <= 21)
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{
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// 7.
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dst_p += k + 1;
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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size = (lit_utf8_size_t) (dst_p - buffer_p);
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for (int32_t i = 0; i < k - n; i++)
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{
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*--dst_p = digits[s % 10];
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s /= 10;
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}
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*--dst_p = dot_char;
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for (int32_t i = 0; i < n; i++)
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{
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*--dst_p = digits[s % 10];
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s /= 10;
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}
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}
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else if (-6 < n && n <= 0)
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{
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// 8.
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dst_p += k - n + 1 + 1;
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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size = (lit_utf8_size_t) (dst_p - buffer_p);
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for (int32_t i = 0; i < k; i++)
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{
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*--dst_p = digits[s % 10];
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s /= 10;
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}
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for (int32_t i = 0; i < -n; i++)
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{
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*--dst_p = digits[0];
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}
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*--dst_p = dot_char;
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*--dst_p = digits[0];
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}
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else
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{
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if (k == 1)
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{
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// 9.
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JERRY_ASSERT (1 <= buffer_size);
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size = 1;
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*dst_p++ = digits[s % 10];
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s /= 10;
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}
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else
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{
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// 10.
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dst_p += k + 1;
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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for (int32_t i = 0; i < k - 1; i++)
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{
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*--dst_p = digits[s % 10];
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s /= 10;
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}
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*--dst_p = dot_char;
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*--dst_p = digits[s % 10];
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s /= 10;
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dst_p += k + 1;
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}
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// 9., 10.
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JERRY_ASSERT (dst_p + 2 <= buffer_p + buffer_size);
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*dst_p++ = e_chars[0];
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*dst_p++ = (n >= 1) ? plus_char : minus_char;
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int32_t t = (n >= 1) ? (n - 1) : -(n - 1);
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if (t == 0)
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{
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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*dst_p++ = digits[0];
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}
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else
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{
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int32_t t_mod = 1000000000u;
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while ((t / t_mod) == 0)
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{
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t_mod /= 10;
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JERRY_ASSERT (t != 0);
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}
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while (t_mod != 0)
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{
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JERRY_ASSERT (dst_p + 1 <= buffer_p + buffer_size);
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*dst_p++ = digits[t / t_mod];
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t -= (t / t_mod) * t_mod;
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t_mod /= 10;
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}
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}
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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size = (lit_utf8_size_t) (dst_p - buffer_p);
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}
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JERRY_ASSERT (s == 0);
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}
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}
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// 10.
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memmove (dst_p + 2, dst_p + 1, (size_t) (k - 1));
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*(dst_p + 1) = LIT_CHAR_DOT;
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dst_p += k + 1;
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}
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return size;
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// 9., 10.
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*dst_p++ = LIT_CHAR_LOWERCASE_E;
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*dst_p++ = (n >= 1) ? LIT_CHAR_PLUS : LIT_CHAR_MINUS;
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uint32_t t = (uint32_t) (n >= 1 ? (n - 1) : -(n - 1));
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dst_p += ecma_uint32_to_utf8_string (t, dst_p, (lit_utf8_size_t) (buffer_p + buffer_size - dst_p));
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JERRY_ASSERT (dst_p <= buffer_p + buffer_size);
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||||
|
||||
return (lit_utf8_size_t) (dst_p - buffer_p);
|
||||
} /* ecma_number_to_utf8_string */
|
||||
|
||||
/**
|
||||
|
||||
Reference in New Issue
Block a user