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Update ffc.h : faster numbers parsing #299

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Merged
nickva merged 1 commit into from
Jun 13, 2026
Merged

Update ffc.h : faster numbers parsing #299

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21 changes: 15 additions & 6 deletions c_src/ffc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -114,8 +114,8 @@ extern "C" {
#define FFC_API

#define FFC_VERSION_YEAR 26
#define FFC_VERSION_MONTH 03
#define FFC_VERSION_BUILD 03
#define FFC_VERSION_MONTH 04
#define FFC_VERSION_BUILD 01
#define FFC_VERSION ((FFC_VERSION_YEAR << 16) | (FFC_VERSION_MONTH << 8) | (FFC_VERSION_BUILD))
#define FFC_VERSION_STRINGIFY_(x) #x
#define FFC_VERSION_STRINGIFY(x) FFC_VERSION_STRINGIFY_(x)
Expand Down Expand Up @@ -1125,13 +1125,22 @@ ffc_internal ffc_inline void
ffc_loop_parse_if_eight_digits(char const **p, char const *const pend,
uint64_t* i) {
// optimizes better than parse_if_eight_digits_unrolled() for char.
while ((pend - *p >= 8) &&
ffc_is_made_of_eight_digits_fast(ffc_read8_to_u64(*p))) {
*i = (*i * 100000000) +
ffc_parse_eight_digits_unrolled_swar(ffc_read8_to_u64(*p));
while (pend - *p >= 8) {
uint64_t val = ffc_read8_to_u64(*p);
if (!ffc_is_made_of_eight_digits_fast(val)) { break; }
*i = (*i * 100000000) + ffc_parse_eight_digits_unrolled_swar(val);
// in rare cases, this will overflow, but that's ok
*p += 8;
}
// 4-digit follow-up: handles sub-8 remainders (e.g. 7-digit fractions)
// without falling all the way to byte-by-byte for the first 4 digits.
if (pend - *p >= 4) {
uint32_t val4 = ffc_read4_to_u32(*p);
if (ffc_is_made_of_four_digits_fast(val4)) {
*i = (*i * 10000) + ffc_parse_four_digits_unrolled(val4);
*p += 4;
}
}
}

/* section end: read digits */
Expand Down
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