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Expose extra-field time extraction utility logic
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src/main/java/software/coley/lljzip/util/ExtraFieldTime.java
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,160 @@ | ||
| package software.coley.lljzip.util; | ||
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| import software.coley.lljzip.format.model.CentralDirectoryFileHeader; | ||
| import software.coley.lljzip.format.model.LocalFileHeader; | ||
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| import javax.annotation.Nonnull; | ||
| import javax.annotation.Nullable; | ||
| import java.nio.file.attribute.FileTime; | ||
| import java.util.concurrent.TimeUnit; | ||
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| /** | ||
| * Utils for extracting more detailed timestamps from file headers. | ||
| * | ||
| * @author Matt Coley | ||
| */ | ||
| public class ExtraFieldTime { | ||
| /** | ||
| * @param header | ||
| * File header to pull detailed time from. | ||
| * | ||
| * @return Time wrapper if values were found. Otherwise, {@code null}. | ||
| */ | ||
| @Nullable | ||
| public static TimeWrapper read(@Nonnull CentralDirectoryFileHeader header) { | ||
| int extraLen = header.getExtraFieldLength(); | ||
| if (extraLen > 0 && extraLen < 0xFFFF) { | ||
| ByteData extra = header.getExtraField(); | ||
| return read(extra); | ||
| } | ||
| return null; | ||
| } | ||
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| /** | ||
| * @param header | ||
| * File header to pull detailed time from. | ||
| * | ||
| * @return Time wrapper if values were found. Otherwise, {@code null}. | ||
| */ | ||
| @Nullable | ||
| public static TimeWrapper read(@Nonnull LocalFileHeader header) { | ||
| int extraLen = header.getExtraFieldLength(); | ||
| if (extraLen > 0 && extraLen < 0xFFFF) { | ||
| ByteData extra = header.getExtraField(); | ||
| return read(extra); | ||
| } | ||
| return null; | ||
| } | ||
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| @Nonnull | ||
| private static TimeWrapper read(@Nonnull ByteData extra) { | ||
| TimeWrapper wrapper = new TimeWrapper(); | ||
| // Reimplementation of 'java.util.zip.ZipEntry#setExtra0(...)' | ||
| int off = 0; | ||
| int len = (int) extra.length(); | ||
| while (off + 4 < len) { | ||
| int tag = extra.getShort(off); | ||
| int size = extra.getShort(off + 2); | ||
| off += 4; | ||
| if (off + size > len) | ||
| break; | ||
| if (tag == /* EXTID_NTFS */ 0xA) { | ||
| if (size < 32) // reserved 4 bytes + tag 2 bytes + size 2 bytes | ||
| break; // m[a|c]time 24 bytes | ||
| int pos = off + 4; | ||
| if (extra.getShort(pos) != 0x0001 || extra.getShort(pos + 2) != 24) | ||
| break; | ||
| long wtime; | ||
| wtime = extra.getInt(pos + 4) | ((long) extra.getInt(pos + 8) << 32); | ||
| if (wtime != Long.MIN_VALUE) { | ||
| wrapper.modify = winTimeToFileTime(wtime).toMillis(); | ||
| } | ||
| wtime = extra.getInt(pos + 12) | ((long) extra.getInt(pos + 16) << 32); | ||
| if (wtime != Long.MIN_VALUE) { | ||
| wrapper.access = winTimeToFileTime(wtime).toMillis(); | ||
| } | ||
| wtime = extra.getInt(pos + 20) | ((long) extra.getInt(pos + 8) << 24); | ||
| if (wtime != Long.MIN_VALUE) { | ||
| wrapper.creation = winTimeToFileTime(wtime).toMillis(); | ||
| } | ||
| } else if (tag == /* EXTID_EXTT */ 0x5455) { | ||
| int flag = extra.get(off); | ||
| int localOff = 1; | ||
| // The CEN-header extra field contains the modification | ||
| // time only, or no timestamp at all. 'sz' is used to | ||
| // flag its presence or absence. But if mtime is present | ||
| // in LOC it must be present in CEN as well. | ||
| if ((flag & 0x1) != 0 && (localOff + 4) <= size) { | ||
| // get32S(extra, off + localOff) | ||
| wrapper.modify = unixTimeToFileTime(extra.getInt(off + localOff)).toMillis(); | ||
| localOff += 4; | ||
| } | ||
| if ((flag & 0x2) != 0 && (localOff + 4) <= size) { | ||
| wrapper.access = unixTimeToFileTime(extra.getInt(off + localOff)).toMillis(); | ||
| localOff += 4; | ||
| } | ||
| if ((flag & 0x4) != 0 && (localOff + 4) <= size) { | ||
| wrapper.creation = unixTimeToFileTime(extra.getInt(off + localOff)).toMillis(); | ||
| localOff += 4; | ||
| } | ||
| } | ||
| off += size; | ||
| } | ||
| return wrapper; | ||
| } | ||
|
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| /** | ||
| * Conversion of windows time to {@link FileTime}. | ||
| * | ||
| * @param time | ||
| * Input windows time value, in microseconds from the windows epoch. | ||
| * | ||
| * @return Mapped file time. | ||
| */ | ||
| @Nonnull | ||
| public static FileTime winTimeToFileTime(long time) { | ||
| return FileTime.from(time / 10 + -11644473600000000L /* windows epoch */, TimeUnit.MICROSECONDS); | ||
| } | ||
|
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| /** | ||
| * Conversion of unix time to {@link FileTime}. | ||
| * | ||
| * @param utime | ||
| * Input unix time value in seconds. | ||
| * | ||
| * @return Mapped file time. | ||
| */ | ||
| @Nonnull | ||
| public static FileTime unixTimeToFileTime(long utime) { | ||
| return FileTime.from(utime, TimeUnit.SECONDS); | ||
| } | ||
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| /** | ||
| * Time wrapper for creation/access/modify times stored in {@link LocalFileHeader#getExtraField()} and | ||
| * {@link CentralDirectoryFileHeader#getExtraField()}. | ||
| */ | ||
| public static class TimeWrapper { | ||
| private long creation, access, modify; | ||
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| /** | ||
| * @return Unix timestamp of creation time. | ||
| */ | ||
| public long getCreationMs() { | ||
| return creation; | ||
| } | ||
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| /** | ||
| * @return Unix timestamp of access time. | ||
| */ | ||
| public long getAccessMs() { | ||
| return access; | ||
| } | ||
|
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| /** | ||
| * @return Unix timestamp of modification time. | ||
| */ | ||
| public long getModifyMs() { | ||
| return modify; | ||
| } | ||
| } | ||
| } |
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