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perf(Time): try to avoid std::regex
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@mcakircali
mcakircali committed Aug 16, 2024
1 parent 6bd664f commit 58440a2
Showing 1 changed file with 89 additions and 62 deletions.
151 changes: 89 additions & 62 deletions src/eckit/types/Time.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -8,34 +8,64 @@
* does it submit to any jurisdiction.
*/

#include <regex>
#include <cctype>
#include <cmath>
#include <cstddef>
#include <regex>
#include <string>
#include <string_view>

#include "eckit/eckit.h"

#include "eckit/exception/Exceptions.h"
#include "eckit/persist/DumpLoad.h"
#include "eckit/types/Time.h"
#include "eckit/utils/Hash.h"
#include "eckit/utils/Tokenizer.h"

namespace {
static thread_local std::regex digits_time_("^-?[0-9]+$");
static thread_local std::regex float_hours_("^-?[0-9]*\\.[0-9]+$");
static thread_local std::regex hhmmss_("^([0-9]+):([0-5]?[0-9])(:[0-5]?[0-9])?$");
static thread_local std::regex ddhhmmss_("^-?([0-9]+[dD])?([0-9]+[hH])?([0-9]+[mM])?([0-9]+[sS])?$");
}

namespace eckit {

//----------------------------------------------------------------------------------------------------------------------

inline void printTime(std::ostream& s, long n) {
const std::regex hhmmss_("^([0-9]+):([0-5]?[0-9])(:[0-5]?[0-9])?$");
const std::regex ddhhmmss_("^-?([0-9]+[dD])?([0-9]+[hH])?([0-9]+[mM])?([0-9]+[sS])?$");

// DIGITS: "^-?[0-9]+$"
// FLOAT: "^-?[0-9]*\\.[0-9]+$"
enum class TimeFormat { UNKOWN, OTHER, DIGITS, DECIMAL };

TimeFormat checkTimeFormat(const std::string_view time) {
bool hasDigit = false;
bool hasDecimal = false;

const std::size_t start = (time[0] == '-') ? 1 : 0;

for (auto i = start; i < time.length(); i++) {
if (time[i] == '.') {
if (hasDecimal || i == time.length() - 1) { return TimeFormat::UNKOWN; }
hasDecimal = true;
} else if (isdigit(time[i]) == 0) {
return TimeFormat::OTHER;
} else {
hasDigit = true;
}
}

if (!hasDigit) { return TimeFormat::UNKOWN; }

return hasDecimal ? TimeFormat::DECIMAL : TimeFormat::DIGITS;
}

void printTime(std::ostream& s, long n) {
if (n < 10) {
s << '0';
}
s << n;
}

} // namespace

//----------------------------------------------------------------------------------------------------------------------

namespace eckit {

Time::Time(long seconds, bool extended) :
seconds_(static_cast<Second>(seconds)) {
if ((seconds >= 86400 && !extended) || seconds < 0) {
Expand All @@ -50,9 +80,10 @@ Time::Time(const std::string& s, bool extended) {
long mm = 0;
long hh = 0;
long dd = 0;
std::smatch m;

if (std::regex_match (s, m, digits_time_)) {

const auto format = checkTimeFormat(s);

if (format == TimeFormat::DIGITS) {
long t = std::stol(s);
int sign = (s[0] == '-' ? 1 : 0);
if (extended || s.length() <= 2+sign) { // cases: h, hh, (or hhh..h for step parsing)
Expand All @@ -67,60 +98,56 @@ Time::Time(const std::string& s, bool extended) {
ss = t % 100;
}
}
}
else {
if (std::regex_match (s, m, float_hours_)) {
long sec = std::round(std::stod(s)*3600);
hh = sec/3600;
sec -= hh*3600;
mm = sec/60;
sec -= mm*60;
ss = sec;
}
else {
if (std::regex_match (s, m, hhmmss_)) {
for (int i=1; i<m.size(); i++) {
if (m[i].matched) {
switch (i) {
case 1: hh = std::stol(m[i].str()); break;
case 2: mm = std::stol(m[i].str()); break;
case 3: std::string aux = m[i].str();
aux.erase(0,1);
ss = std::stol(aux); break;
}
} else if (format == TimeFormat::DECIMAL) {
long sec = std::round(std::stod(s) * 3600);
hh = sec / 3600;
sec -= hh * 3600;
mm = sec / 60;
sec -= mm * 60;
ss = sec;
} else if (format == TimeFormat::OTHER) {
std::smatch m;
if (std::regex_match(s, m, hhmmss_)) {
for (int i = 1; i < m.size(); i++) {
if (m[i].matched) {
switch (i) {
case 1: hh = std::stol(m[i].str()); break;
case 2: mm = std::stol(m[i].str()); break;
case 3:
std::string aux = m[i].str();
aux.erase(0, 1);
ss = std::stol(aux);
break;
}
}
}
else {
if (std::regex_match (s, m, ddhhmmss_)) {
for (int i=1; i<m.size(); i++) {
if (m[i].matched) {
std::string aux = m[i].str();
aux.pop_back();
long t = std::stol(aux);
switch (i) {
case 1: dd = t; break;
case 2: hh = t; break;
case 3: mm = t; break;
case 4: ss = t;
}
}
}
ss += 60 * (mm + 60 * (hh + 24 * dd));
if (s[0] == '-') {
ss = -ss;
} else if (std::regex_match(s, m, ddhhmmss_)) {
for (int i = 1; i < m.size(); i++) {
if (m[i].matched) {
std::string aux = m[i].str();
aux.pop_back();
long t = std::stol(aux);
switch (i) {
case 1: dd = t; break;
case 2: hh = t; break;
case 3: mm = t; break;
case 4: ss = t;
}
dd = ss / 86400;
hh = (ss / 3600) % 24;
mm = (ss / 60) % 60;
ss = ss % 60;
} else {
std::string msg = "Wrong input for time: ";
msg += s;
throw BadTime(msg);
}
}
ss += 60 * (mm + 60 * (hh + 24 * dd));
if (s[0] == '-') { ss = -ss; }
dd = ss / 86400;
hh = (ss / 3600) % 24;
mm = (ss / 60) % 60;
ss = ss % 60;
} else {
throw BadTime("Wrong input for time: " + s);
}
} else if (format == TimeFormat::UNKOWN) {
throw BadTime("Unkown format for time: " + s);
} else {
throw SeriousBug("Unhandled time format!");
}

if (mm >= 60 || ss >= 60 || (!extended && (hh >= 24 || dd > 0 || hh < 0 || mm < 0 || ss < 0))) {
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