1/* 2 * Copyright (C) 2010 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17#define LOG_TAG "MtpUtils" 18 19#include <stdio.h> 20#include <time.h> 21 22#include "MtpUtils.h" 23 24namespace android { 25 26/* 27DateTime strings follow a compatible subset of the definition found in ISO 8601, and 28take the form of a Unicode string formatted as: "YYYYMMDDThhmmss.s". In this 29representation, YYYY shall be replaced by the year, MM replaced by the month (01-12), 30DD replaced by the day (01-31), T is a constant character 'T' delimiting time from date, 31hh is replaced by the hour (00-23), mm is replaced by the minute (00-59), and ss by the 32second (00-59). The ".s" is optional, and represents tenths of a second. 33This is followed by a UTC offset given as "[+-]zzzz" or the literal "Z", meaning UTC. 34*/ 35 36bool parseDateTime(const char* dateTime, time_t& outSeconds) { 37 int year, month, day, hour, minute, second; 38 if (sscanf(dateTime, "%04d%02d%02dT%02d%02d%02d", 39 &year, &month, &day, &hour, &minute, &second) != 6) 40 return false; 41 42 // skip optional tenth of second 43 const char* tail = dateTime + 15; 44 if (tail[0] == '.' && tail[1]) tail += 2; 45 46 // FIXME: "Z" means UTC, but non-"Z" doesn't mean local time. 47 // It might be that you're in Asia/Seoul on vacation and your Android 48 // device has noticed this via the network, but your camera was set to 49 // America/Los_Angeles once when you bought it and doesn't know where 50 // it is right now, so the camera says "20160106T081700-0800" but we 51 // just ignore the "-0800" and assume local time which is actually "+0900". 52 // I think to support this (without switching to Java or using icu4c) 53 // you'd want to always use timegm(3) and then manually add/subtract 54 // the UTC offset parsed from the string (taking care of wrapping). 55 // mktime(3) ignores the tm_gmtoff field, so you can't let it do the work. 56 bool useUTC = (tail[0] == 'Z'); 57 58 struct tm tm = {}; 59 tm.tm_sec = second; 60 tm.tm_min = minute; 61 tm.tm_hour = hour; 62 tm.tm_mday = day; 63 tm.tm_mon = month - 1; // mktime uses months in 0 - 11 range 64 tm.tm_year = year - 1900; 65 tm.tm_isdst = -1; 66 outSeconds = useUTC ? timegm(&tm) : mktime(&tm); 67 68 return true; 69} 70 71void formatDateTime(time_t seconds, char* buffer, int bufferLength) { 72 struct tm tm; 73 74 localtime_r(&seconds, &tm); 75 snprintf(buffer, bufferLength, "%04d%02d%02dT%02d%02d%02d", 76 tm.tm_year + 1900, 77 tm.tm_mon + 1, // localtime_r uses months in 0 - 11 range 78 tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec); 79} 80 81} // namespace android 82