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backends/cloud/iso8601.cpp

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+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "backends/cloud/iso8601.h"
+#include "common/str.h"
+
+namespace {
+
+Common::String getSubstring(const Common::String &s, uint32 beginning, uint32 ending) {
+	//beginning inclusive, ending exclusive
+	Common::String result = s;
+	result.erase(ending);
+	result.erase(0, beginning);
+	return result;
+}
+
+int find(const char *cstr, uint32 startPosition, char needle) {
+	const char *res = strchr(cstr + startPosition, needle);
+	if (res == nullptr)
+		return -1;
+	return res - cstr;
+}
+
+}
+
+namespace Cloud {
+namespace ISO8601 {
+
+uint32 convertToTimestamp(const Common::String &iso8601Date) {
+	//2015-05-12T15:50:38Z
+	const char *cstr = iso8601Date.c_str();
+	int firstHyphen = find(cstr, 0, '-');
+	int secondHyphen = find(cstr, firstHyphen + 1, '-');
+	int tSeparator = find(cstr, secondHyphen + 1, 'T');
+	int firstColon = find(cstr, tSeparator + 1, ':');
+	int secondColon = find(cstr, firstColon + 1, ':');
+	int zSeparator = find(cstr, secondColon + 1, 'Z');
+	if (zSeparator == -1)
+		zSeparator = find(cstr, secondColon + 1, '-'); // Box's RFC 3339
+	//now note '+1' which means if there ever was '-1' result of find(), we still did a valid find() from 0th char
+
+	Common::String year = getSubstring(iso8601Date, 0, firstHyphen);
+	Common::String month = getSubstring(iso8601Date, firstHyphen + 1, secondHyphen);
+	Common::String day = getSubstring(iso8601Date, secondHyphen + 1, tSeparator);
+	Common::String hour = getSubstring(iso8601Date, tSeparator + 1, firstColon);
+	Common::String minute = getSubstring(iso8601Date, firstColon + 1, secondColon);
+	Common::String second = getSubstring(iso8601Date, secondColon + 1, zSeparator);
+	//now note only 'ending' argument was not '+1' (which means I could've make that function such that -1 means 'until the end')
+
+	int Y = atoi(year.c_str());
+	int M = atoi(month.c_str());
+	int D = atoi(day.c_str());
+	int h = atoi(hour.c_str());
+	int m = atoi(minute.c_str());
+	int s = atoi(second.c_str());
+
+	//ok, now I compose a timestamp based on my basic perception of time/date
+	//yeah, I know about leap years and leap seconds and all, but still we don't care there
+
+	uint32 days = D - 1;
+	for (int i = 1970; i < Y; ++i)
+		if ((i % 4 == 0 && i % 100 != 0) || (i % 400 == 0))
+			days += 366;
+		else
+			days += 365;
+
+	int mdays[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
+	for (int i = 1; i < M; ++i) {
+		days += mdays[i - 1];
+		if (i == 2)
+			if ((Y % 4 == 0 && Y % 100 != 0) || (Y % 400 == 0))
+				days += 1;
+	}
+
+	uint32 hours = days * 24 + h;
+	uint32 minutes = hours * 60 + m;
+	return minutes * 60 + s;
+}
+
+} // End of namespace ISO8601
+} // End of namespace Cloud