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Merged
lemire merged 3 commits into from
Dec 24, 2025
+30 −55
Merged

even simpler bench_ip functions #352

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0b11d0a
even simpler bench_ip function
lemire Dec 24, 2025
f9ddc75
removing space
lemire Dec 24, 2025
a6a229a
bumping tag
lemire Dec 24, 2025
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2 changes: 1 addition & 1 deletion benchmarks/CMakeLists.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@ include(FetchContent)
FetchContent_Declare(
counters
GIT_REPOSITORY https://github.com/lemire/counters.git
GIT_TAG v2.1.0
GIT_TAG v2.2.0
)

FetchContent_MakeAvailable(counters)
Expand Down
83 changes: 29 additions & 54 deletions benchmarks/bench_ip.cpp
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Expand Up @@ -52,61 +52,36 @@ fastfloat_really_inline const char *seek_ip_end(const char *p,
return current;
}

fastfloat_really_inline int parse_u8_fastfloat(const char *&p, const char *pend,
uint8_t *out) {
if (p == pend)
return 0;
auto r = fast_float::from_chars(p, pend, *out);
if (r.ec == std::errc()) {
p = r.ptr;
return 1;
}
return 0;
}
enum class parse_method { standard, fast_float };

fastfloat_really_inline int parse_u8_fromchars(const char *&p, const char *pend,
uint8_t *out) {
if (p == pend) {
return 0;
}
auto r = std::from_chars(p, pend, *out);
if (r.ec == std::errc()) {
p = r.ptr;
return 1;
}
return 0;
}

template <typename Parser>
template <parse_method use_standard>
fastfloat_really_inline std::pair<bool, uint32_t>
simple_parse_ip_line(const char *p, const char *pend, Parser parse_uint8) {
uint8_t v1;
if (!parse_uint8(p, pend, &v1)) {
return {false, 0};
}
if (p == pend || *p++ != '.') {
return {false, 0};
}
uint8_t v2;
if (!parse_uint8(p, pend, &v2)) {
return {false, 0};
}
if (p == pend || *p++ != '.') {
return {false, 0};
}
uint8_t v3;
if (!parse_uint8(p, pend, &v3)) {
return {false, 0};
}
if (p == pend || *p++ != '.') {
return {false, 0};
}
uint8_t v4;
if (!parse_uint8(p, pend, &v4)) {
return {false, 0};
simple_parse_ip_line(const char *p, const char *pend) {
const char *current = p;
uint32_t ip = 0;
for (int i = 0; i < 4; ++i) {
uint8_t value;
if constexpr (use_standard == parse_method::standard) {
auto r = std::from_chars(current, pend, value);
if (r.ec != std::errc()) {
return {false, 0};
}
current = r.ptr;
} else if constexpr (use_standard == parse_method::fast_float) {
auto r = fast_float::from_chars(current, pend, value);
if (r.ec != std::errc()) {
return {false, 0};
}
current = r.ptr;
}
ip = (ip << 8) | value;
if (i < 3) {
if (current == pend || *current++ != '.') {
return {false, 0};
}
}
}
return {true, (uint32_t(v1) << 24) | (uint32_t(v2) << 16) |
(uint32_t(v3) << 8) | uint32_t(v4)};
return {true, ip};
}

static std::string make_ip_line(uint8_t a, uint8_t b, uint8_t c, uint8_t d) {
Expand Down Expand Up @@ -176,7 +151,7 @@ int main() {
int ok = 0;
for (size_t i = 0; i < N; ++i) {
auto [ok, ip] =
simple_parse_ip_line(p, pend, parse_u8_fromchars);
simple_parse_ip_line<parse_method::standard>(p, pend);
sum += ip;
if (!ok) {
std::abort();
Expand All @@ -193,7 +168,7 @@ int main() {
int ok = 0;
for (size_t i = 0; i < N; ++i) {
auto [ok, ip] =
simple_parse_ip_line(p, pend, parse_u8_fastfloat);
simple_parse_ip_line<parse_method::fast_float>(p, pend);
sum += ip;
if (!ok) {
std::abort();
Expand Down