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25 
26 package java.util.zip;
27 
28 import java.nio.file.attribute.FileTime;
29 import java.util.Date;
30 import java.util.concurrent.TimeUnit;
31 
32 class ZipUtils {
33 
34     // used to adjust values between Windows and java epoch
35     private static final long WINDOWS_EPOCH_IN_MICROSECONDS = -11644473600000000L;
36 
37     /**
38      * Converts Windows time (in microseconds, UTC/GMT) time to FileTime.
39      */
winTimeToFileTime(long wtime)40     public static final FileTime winTimeToFileTime(long wtime) {
41         return FileTime.from(wtime / 10 + WINDOWS_EPOCH_IN_MICROSECONDS,
42                              TimeUnit.MICROSECONDS);
43     }
44 
45     /**
46      * Converts FileTime to Windows time.
47      */
fileTimeToWinTime(FileTime ftime)48     public static final long fileTimeToWinTime(FileTime ftime) {
49         return (ftime.to(TimeUnit.MICROSECONDS) - WINDOWS_EPOCH_IN_MICROSECONDS) * 10;
50     }
51 
52     /**
53      * Converts "standard Unix time"(in seconds, UTC/GMT) to FileTime
54      */
unixTimeToFileTime(long utime)55     public static final FileTime unixTimeToFileTime(long utime) {
56         return FileTime.from(utime, TimeUnit.SECONDS);
57     }
58 
59     /**
60      * Converts FileTime to "standard Unix time".
61      */
fileTimeToUnixTime(FileTime ftime)62     public static final long fileTimeToUnixTime(FileTime ftime) {
63         return ftime.to(TimeUnit.SECONDS);
64     }
65 
66     /**
67      * Converts DOS time to Java time (number of milliseconds since epoch).
68      */
dosToJavaTime(long dtime)69     private static long dosToJavaTime(long dtime) {
70         @SuppressWarnings("deprecation") // Use of date constructor.
71         Date d = new Date((int)(((dtime >> 25) & 0x7f) + 80),
72                           (int)(((dtime >> 21) & 0x0f) - 1),
73                           (int)((dtime >> 16) & 0x1f),
74                           (int)((dtime >> 11) & 0x1f),
75                           (int)((dtime >> 5) & 0x3f),
76                           (int)((dtime << 1) & 0x3e));
77         return d.getTime();
78     }
79 
80     /**
81      * Converts extended DOS time to Java time, where up to 1999 milliseconds
82      * might be encoded into the upper half of the returned long.
83      *
84      * @param xdostime the extended DOS time value
85      * @return milliseconds since epoch
86      */
extendedDosToJavaTime(long xdostime)87     public static long extendedDosToJavaTime(long xdostime) {
88         long time = dosToJavaTime(xdostime);
89         return time + (xdostime >> 32);
90     }
91 
92     /**
93      * Converts Java time to DOS time.
94      */
95     @SuppressWarnings("deprecation") // Use of date methods
javaToDosTime(long time)96     private static long javaToDosTime(long time) {
97         Date d = new Date(time);
98         int year = d.getYear() + 1900;
99         if (year < 1980) {
100             return ZipEntry.DOSTIME_BEFORE_1980;
101         }
102         return (year - 1980) << 25 | (d.getMonth() + 1) << 21 |
103                d.getDate() << 16 | d.getHours() << 11 | d.getMinutes() << 5 |
104                d.getSeconds() >> 1;
105     }
106 
107     /**
108      * Converts Java time to DOS time, encoding any milliseconds lost
109      * in the conversion into the upper half of the returned long.
110      *
111      * @param time milliseconds since epoch
112      * @return DOS time with 2s remainder encoded into upper half
113      */
javaToExtendedDosTime(long time)114     public static long javaToExtendedDosTime(long time) {
115         if (time < 0) {
116             return ZipEntry.DOSTIME_BEFORE_1980;
117         }
118         long dostime = javaToDosTime(time);
119         return (dostime != ZipEntry.DOSTIME_BEFORE_1980)
120                 ? dostime + ((time % 2000) << 32)
121                 : ZipEntry.DOSTIME_BEFORE_1980;
122     }
123 
124     /**
125      * Fetches unsigned 16-bit value from byte array at specified offset.
126      * The bytes are assumed to be in Intel (little-endian) byte order.
127      */
get16(byte b[], int off)128     public static final int get16(byte b[], int off) {
129         return Byte.toUnsignedInt(b[off]) | (Byte.toUnsignedInt(b[off+1]) << 8);
130     }
131 
132     /**
133      * Fetches unsigned 32-bit value from byte array at specified offset.
134      * The bytes are assumed to be in Intel (little-endian) byte order.
135      */
get32(byte b[], int off)136     public static final long get32(byte b[], int off) {
137         return (get16(b, off) | ((long)get16(b, off+2) << 16)) & 0xffffffffL;
138     }
139 
140     /**
141      * Fetches signed 64-bit value from byte array at specified offset.
142      * The bytes are assumed to be in Intel (little-endian) byte order.
143      */
get64(byte b[], int off)144     public static final long get64(byte b[], int off) {
145         return get32(b, off) | (get32(b, off+4) << 32);
146     }
147 }
148