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allow parsing and formatting of negative times #207

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Merged
rsjbailey merged 3 commits into from
Dec 4, 2025
Merged

allow parsing and formatting of negative times #207

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2d71bd6
allow parsing and formatting of negative times
rsjbailey Dec 2, 2025
763ca45
fix formatting
rsjbailey Dec 2, 2025
1388db3
Add missing header
rsjbailey Dec 2, 2025
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64 changes: 43 additions & 21 deletions src/elements/time.cpp
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
#include "adm/elements/time.hpp"
#include <boost/integer/common_factor.hpp>
#include <cmath>
#include <iomanip>
#include <regex>
#include <sstream>
Expand Down Expand Up @@ -49,13 +50,14 @@ namespace adm {
}

Time parseTimecode(const std::string& timecode) {
const static std::regex commonFormat("(\\d{2}):(\\d{2}):(\\d{2}).(\\d+)");
const static std::regex commonFormat(
R"((-?)(\d{2}):(\d{2}):(\d{2}).(\d+))");
const static std::regex fractionalFormat(
"(\\d{2}):(\\d{2}):(\\d{2}).(\\d+)S(\\d+)");
R"((-?)(\d{2}):(\d{2}):(\d{2}).(\d+)S(\d+))");

std::smatch timecodeMatch;
if (std::regex_match(timecode, timecodeMatch, commonFormat)) {
const std::string& ns_str = timecodeMatch[4];
const std::string& ns_str = timecodeMatch[5];

// parse number of nanoseconds as if it always had 9 digits
int64_t ns = 0;
Expand All @@ -64,18 +66,21 @@ namespace adm {
if (i < ns_str.size()) ns += place_value * (ns_str[i] - '0');
place_value *= 10;
}
auto isPositive = timecodeMatch[1].str().empty();

return std::chrono::hours(stoi(timecodeMatch[1])) +
std::chrono::minutes(stoi(timecodeMatch[2])) +
std::chrono::seconds(stoi(timecodeMatch[3])) +
std::chrono::nanoseconds(ns);
return (isPositive ? 1 : -1) *
(std::chrono::hours(stoi(timecodeMatch[2])) +
std::chrono::minutes(stoi(timecodeMatch[3])) +
std::chrono::seconds(stoi(timecodeMatch[4])) +
std::chrono::nanoseconds(ns));
} else if (std::regex_match(timecode, timecodeMatch, fractionalFormat)) {
int64_t seconds = 3600 * stoi(timecodeMatch[1]) +
60 * stoi(timecodeMatch[2]) +
1 * stoi(timecodeMatch[3]);
auto isPositive = timecodeMatch[1].str().empty();
int64_t seconds = 3600 * stoi(timecodeMatch[2]) +
60 * stoi(timecodeMatch[3]) +
1 * stoi(timecodeMatch[4]);

int64_t numerator = stoi(timecodeMatch[4]);
int64_t denominator = stoi(timecodeMatch[5]);
int64_t numerator = stoi(timecodeMatch[5]);
int64_t denominator = stoi(timecodeMatch[6]);

if (denominator == 0) {
std::stringstream errorString;
Expand All @@ -84,7 +89,9 @@ namespace adm {
throw std::runtime_error(errorString.str());
}

return FractionalTime{seconds * denominator + numerator, denominator};
return FractionalTime{
(isPositive ? 1 : -1) * (seconds * denominator + numerator),
denominator};
} else {
std::stringstream errorString;
errorString << "invalid timecode: " << timecode;
Expand All @@ -95,18 +102,27 @@ namespace adm {
struct FormatTimeVisitor : public boost::static_visitor<std::string> {
std::string operator()(const std::chrono::nanoseconds& time) const {
std::stringstream ss;
auto formatTime = time;
if (formatTime.count() < 0) {
formatTime = -formatTime;
ss << '-';
}
ss << std::setw(2) << std::setfill('0')
<< std::chrono::duration_cast<std::chrono::hours>(time).count();
<< std::chrono::duration_cast<std::chrono::hours>(formatTime).count();
ss << ":";
ss << std::setw(2) << std::setfill('0')
<< std::chrono::duration_cast<std::chrono::minutes>(time).count() % 60;
<< std::chrono::duration_cast<std::chrono::minutes>(formatTime)
.count() %
60;
ss << ":";
ss << std::setw(2) << std::setfill('0')
<< std::chrono::duration_cast<std::chrono::seconds>(time).count() % 60;
<< std::chrono::duration_cast<std::chrono::seconds>(formatTime)
.count() %
60;
ss << ".";

{
auto ns = time.count() % 1000000000;
auto ns = formatTime.count() % 1000000000;
// drop trailing zero digits, while keeping at least 5 to satisfy BS.2076-2
int precision = 9;
while (ns % 10 == 0 && precision > 5) {
Expand All @@ -120,18 +136,24 @@ namespace adm {
}

std::string operator()(const FractionalTime& time) const {
int64_t whole_seconds = time.numerator() / time.denominator();
int64_t frac_numerator =
time.numerator() - whole_seconds * time.denominator();
auto absNum = abs(time.numerator());
auto absDenom = abs(time.denominator());
int64_t whole_seconds = absNum / absDenom;
int64_t frac_numerator = absNum - whole_seconds * absDenom;

std::stringstream ss;
double floating =
static_cast<double>(time.numerator()) / time.denominator();
if (std::signbit(floating)) {
ss << "-";
}
ss << std::setw(2) << std::setfill('0') << whole_seconds / 3600;
ss << ":";
ss << std::setw(2) << std::setfill('0') << (whole_seconds / 60) % 60;
ss << ":";
ss << std::setw(2) << std::setfill('0') << whole_seconds % 60;
ss << ".";
ss << frac_numerator << "S" << time.denominator();
ss << frac_numerator << "S" << absDenom;
return ss.str();
}
};
Expand Down
52 changes: 52 additions & 0 deletions tests/adm_time_tests.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -114,3 +114,55 @@ TEST_CASE("rational conversion") {

REQUIRE(asTime(RationalTime{1, 2}) == FractionalTime{1, 2});
}

TEST_CASE("Parsed negative zero time == zero time") {
auto time = parseTimecode("-00:00:00.00000");
REQUIRE(time == Time{});
}

TEST_CASE("Negative nanosecond times parsed correctly") {
{
auto time = parseTimecode("-00:00:01.00000");
REQUIRE(time == Time{std::chrono::seconds{-1}});
}
{
auto time = parseTimecode("-00:10:00.00000");
REQUIRE(time == Time{std::chrono::minutes{-10}});
}
}

TEST_CASE("Format negative ns timecode") {
{
auto code = formatTimecode(Time{std::chrono::seconds{-1}});
REQUIRE(code == "-00:00:01.00000");
}
{
auto code = formatTimecode(Time{std::chrono::nanoseconds{-1}});
REQUIRE(code == "-00:00:00.000000001");
}
{
auto code = formatTimecode(Time{std::chrono::minutes{-1}});
REQUIRE(code == "-00:01:00.00000");
}
{
auto code = formatTimecode(Time{std::chrono::hours{-1}});
REQUIRE(code == "-01:00:00.00000");
}
}

TEST_CASE("Parse negative fractional time") {
REQUIRE(parseTimecode("-01:00:00.0S1") == Time(FractionalTime{-3600, 1}));
REQUIRE(parseTimecode("-00:01:00.0S1") == Time(FractionalTime{-60, 1}));
REQUIRE(parseTimecode("-00:00:01.0S1") == Time(FractionalTime{-1, 1}));
REQUIRE(parseTimecode("-00:00:00.1S10") == Time(FractionalTime{-1, 10}));

// test leading zeros
REQUIRE(parseTimecode("-00:00:00.01S010") == Time(FractionalTime{-1, 10}));
}

TEST_CASE("Format negative fractional time") {
REQUIRE("-01:00:00.0S1" == formatTimecode(FractionalTime{-3600, 1}));
REQUIRE("-00:01:00.0S1" == formatTimecode(FractionalTime{-60, 1}));
REQUIRE("-00:00:01.0S1" == formatTimecode(FractionalTime{-1, 1}));
REQUIRE("-00:00:00.1S10" == formatTimecode(FractionalTime{-1, 10}));
}
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