LibGfx: Read profile creation time from ICCProfile header

Userland/Libraries/LibGfx/ICCProfile.cpp

@@ -6,6 +6,7 @@
 
 #include <AK/Endian.h>
 #include <LibGfx/ICCProfile.h>
+#include <time.h>
 
 // V2 spec: https://color.org/specification/ICC.1-2001-04.pdf
 // V4 spec: https://color.org/specification/ICC.1-2022-05.pdf
@@ -14,6 +15,58 @@ namespace Gfx::ICC {
 
 namespace {
 
+// ICC V4, 4.2 dateTimeNumber
+// "All the dateTimeNumber values in a profile shall be in Coordinated Universal Time [...]."
+struct DateTimeNumber {
+    BigEndian<u16> year;
+    BigEndian<u16> month;
+    BigEndian<u16> day;
+    BigEndian<u16> hour;
+    BigEndian<u16> minutes;
+    BigEndian<u16> seconds;
+};
+
+ErrorOr<time_t> parse_date_time_number(DateTimeNumber const& date_time)
+{
+    // ICC V4, 4.2 dateTimeNumber
+
+    // "Number of the month (1 to 12)"
+    if (date_time.month < 1 || date_time.month > 12)
+        return Error::from_string_literal("ICC::Profile: dateTimeNumber month out of bounds");
+
+    // "Number of the day of the month (1 to 31)"
+    if (date_time.day < 1 || date_time.day > 31)
+        return Error::from_string_literal("ICC::Profile: dateTimeNumber day out of bounds");
+
+    // "Number of hours (0 to 23)"
+    if (date_time.hour > 23)
+        return Error::from_string_literal("ICC::Profile: dateTimeNumber hour out of bounds");
+
+    // "Number of minutes (0 to 59)"
+    if (date_time.minutes > 59)
+        return Error::from_string_literal("ICC::Profile: dateTimeNumber minutes out of bounds");
+
+    // "Number of seconds (0 to 59)"
+    // ICC profiles apparently can't be created during leap seconds (seconds would be 60 there, but the spec doesn't allow that).
+    if (date_time.seconds > 59)
+        return Error::from_string_literal("ICC::Profile: dateTimeNumber seconds out of bounds");
+
+    struct tm tm = {};
+    tm.tm_year = date_time.year - 1900;
+    tm.tm_mon = date_time.month - 1;
+    tm.tm_mday = date_time.day;
+    tm.tm_hour = date_time.hour;
+    tm.tm_min = date_time.minutes;
+    tm.tm_sec = date_time.seconds;
+    // timegm() doesn't read tm.tm_isdst, tm.tm_wday, and tm.tm_yday, no need to fill them in.
+
+    time_t timestamp = timegm(&tm);
+    if (timestamp == -1)
+        return Error::from_string_literal("ICC::Profile: dateTimeNumber not representable as timestamp");
+
+    return timestamp;
+}
+
 // ICC V4, 7.2 Profile header
 struct ICCHeader {
     BigEndian<u32> profile_size;
@@ -27,12 +80,7 @@ struct ICCHeader {
     BigEndian<u32> data_color_space;
     BigEndian<u32> pcs; // "Profile Connection Space"
 
-    BigEndian<u16> year;
+    DateTimeNumber profile_creation_time;
-    BigEndian<u16> month;
-    BigEndian<u16> day;
-    BigEndian<u16> hour;
-    BigEndian<u16> minutes;
-    BigEndian<u16> seconds;
 
     BigEndian<u32> profile_file_signature;
     BigEndian<u32> primary_platform;
@@ -78,6 +126,12 @@ ErrorOr<DeviceClass> parse_device_class(ICCHeader const& header)
     return Error::from_string_literal("ICC::Profile: Invalid device class");
 }
 
+ErrorOr<time_t> parse_creation_date_time(ICCHeader const& header)
+{
+    // iCC v4, 7.2.8 Date and time field
+    return parse_date_time_number(header.profile_creation_time);
+}
+
 ErrorOr<void> parse_file_signature(ICCHeader const& header)
 {
     // iCC v4, 7.2.9 Profile file signature field
@@ -121,6 +175,7 @@ ErrorOr<NonnullRefPtr<Profile>> Profile::try_load_from_externally_owned_memory(R
     TRY(parse_file_signature(header));
     profile->m_version = TRY(parse_version(header));
     profile->m_device_class = TRY(parse_device_class(header));
+    profile->m_creation_timestamp = TRY(parse_creation_date_time(header));
 
     return profile;
 }

Userland/Libraries/LibGfx/ICCProfile.h

@@ -51,10 +51,12 @@ public:
 
     Version version() const { return m_version; }
     DeviceClass device_class() const { return m_device_class; }
+    time_t creation_timestamp() const { return m_creation_timestamp; }
 
 private:
     Version m_version;
     DeviceClass m_device_class;
+    time_t m_creation_timestamp;
 };
 
 }