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ext/bcmath: optimized divmod() and mod() take 2 #18058

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ext/bcmath: optimized divmod() and mod() take 2 #18058

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03955d6
Added `bc_divide_copy_numerator()`
SakiTakamachi Mar 14, 2025
aaf1f6a
At the end of the calculation, set the value of `numerator_vectors` t…
SakiTakamachi Mar 14, 2025
b2c1b3f
Changed `bc_divide` to `bc_divide_ex`, and changed three division fun…
SakiTakamachi Mar 14, 2025
c0000cd
Set the sign of `quot` efficiently
SakiTakamachi Mar 14, 2025
0865562
Use `quot` only if `use_quot == true`, in `bc_divide_ex`
SakiTakamachi Mar 14, 2025
5e4b175
Added `bc_convert_vector_to_char()` and `bc_convert_vector_to_char_wi…
SakiTakamachi Mar 14, 2025
13a98ae
Use `quot` only if `use_quot == true`, in other funcs
SakiTakamachi Mar 14, 2025
b949c5e
Roughly write code using `use_rem`
SakiTakamachi Mar 14, 2025
484d9df
Using `rem` in `bc_divide_by_one`
SakiTakamachi Mar 14, 2025
2d63079
Create a process to initialize `bc_num` of `rem`
SakiTakamachi Mar 14, 2025
c7916b5
Using `rem` in `bc_divide_by_pow_10`
SakiTakamachi Mar 14, 2025
a2ba77c
Using `rem` in `bc_do_div`
SakiTakamachi Mar 14, 2025
d3a5713
fixed raisemod
SakiTakamachi Mar 14, 2025
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28 changes: 26 additions & 2 deletions ext/bcmath/libbcmath/src/div.c
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Original file line number Diff line number Diff line change
Expand Up @@ -340,7 +340,10 @@ static inline void bc_divide_by_one(
}

static inline void bc_divide_by_pow_10(
const char *numeratorptr, size_t numerator_readable_size, bc_num *quot, size_t quot_size, size_t quot_scale, bool use_quot)
const char *numeratorptr, size_t numerator_readable_size, size_t numerator_leading_zeros,
bc_num *quot, size_t quot_size, size_t quot_scale, bool use_quot,
bc_num *rem, size_t rem_size, bool use_rem,
size_t numerator_rem_len_diff)
{
if (use_quot) {
char *qptr = (*quot)->n_value;
Expand All @@ -363,6 +366,23 @@ static inline void bc_divide_by_pow_10(
(*quot)->n_scale -= qend - qptr;
}
}
if (use_rem) {
size_t rem_leading_zeros = numerator_leading_zeros + quot_size - numerator_rem_len_diff;
if (rem_size <= rem_leading_zeros) {
bc_free_num(rem);
*rem = bc_copy_num(BCG(_zero_));
return;
}
/* The values after this have already been copied, so just need to set them to 0. */
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Copied by whom?

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About 10 lines above the line where this function is called, there’s the following line:

memcpy((*rem)->n_value + rem_write_size, numerator->n_value + rem_write_size + numerator_rem_len_diff, copy_size);

The intention here was that everything except the leading zeros has already been copied.

for (size_t i = 0; i < rem_leading_zeros; i++) {
(*rem)->n_value[i] = 0;
}
_bc_rm_leading_zeros(*rem);
if (bc_is_zero(*rem)) {
(*rem)->n_sign = PLUS;
(*rem)->n_scale = 0;
}
}
}

bool bc_divide_ex(bc_num numerator, bc_num divisor, bc_num *quot, bc_num *rem, size_t scale, bool use_quot, bool use_rem)
Expand Down Expand Up @@ -492,7 +512,11 @@ bool bc_divide_ex(bc_num numerator, bc_num divisor, bc_num *quot, bc_num *rem, s

/* If divisor is 1 here, return the result of adjusting the decimal point position of numerator. */
if (divisor_size == 1 && *divisorptr == 1) {
bc_divide_by_pow_10(numeratorptr, numerator_readable_size, quot, quot_size, quot_scale);
bc_divide_by_pow_10(
numeratorptr, numerator_readable_size, numerator_leading_zeros,
quot, quot_size, quot_scale, use_quot,
rem, rem_size, use_rem, numerator_rem_len_diff
);
return true;
}

Expand Down