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+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+Package zip provides support for reading and writing ZIP archives.
+
+See: http://www.pkware.com/documents/casestudies/APPNOTE.TXT
+
+This package does not support disk spanning.
+
+A note about ZIP64:
+
+To be backwards compatible the FileHeader has both 32 and 64 bit Size
+fields. The 64 bit fields will always contain the correct value and
+for normal archives both fields will be the same. For files requiring
+the ZIP64 format the 32 bit fields will be 0xffffffff and the 64 bit
+fields must be used instead.
+*/
+package zip
+
+import (
+ "os"
+ "path"
+ "time"
+)
+
+// Compression methods.
+const (
+ Store uint16 = 0
+ Deflate uint16 = 8
+)
+
+const (
+ fileHeaderSignature = 0x04034b50
+ directoryHeaderSignature = 0x02014b50
+ directoryEndSignature = 0x06054b50
+ directory64LocSignature = 0x07064b50
+ directory64EndSignature = 0x06064b50
+ dataDescriptorSignature = 0x08074b50 // de-facto standard; required by OS X Finder
+ fileHeaderLen = 30 // + filename + extra
+ directoryHeaderLen = 46 // + filename + extra + comment
+ directoryEndLen = 22 // + comment
+ dataDescriptorLen = 16 // four uint32: descriptor signature, crc32, compressed size, size
+ dataDescriptor64Len = 24 // descriptor with 8 byte sizes
+ directory64LocLen = 20 //
+ directory64EndLen = 56 // + extra
+
+ // Constants for the first byte in CreatorVersion
+ creatorFAT = 0
+ creatorUnix = 3
+ creatorNTFS = 11
+ creatorVFAT = 14
+ creatorMacOSX = 19
+
+ // version numbers
+ zipVersion20 = 20 // 2.0
+ zipVersion45 = 45 // 4.5 (reads and writes zip64 archives)
+
+ // limits for non zip64 files
+ uint16max = (1 << 16) - 1
+ uint32max = (1 << 32) - 1
+
+ // extra header id's
+ zip64ExtraId = 0x0001 // zip64 Extended Information Extra Field
+)
+
+// FileHeader describes a file within a zip file.
+// See the zip spec for details.
+type FileHeader struct {
+ // Name is the name of the file.
+ // It must be a relative path: it must not start with a drive
+ // letter (e.g. C:) or leading slash, and only forward slashes
+ // are allowed.
+ Name string
+
+ CreatorVersion uint16
+ ReaderVersion uint16
+ Flags uint16
+ Method uint16
+ ModifiedTime uint16 // MS-DOS time
+ ModifiedDate uint16 // MS-DOS date
+ CRC32 uint32
+ CompressedSize uint32 // deprecated; use CompressedSize64
+ UncompressedSize uint32 // deprecated; use UncompressedSize64
+ CompressedSize64 uint64
+ UncompressedSize64 uint64
+ Extra []byte
+ ExternalAttrs uint32 // Meaning depends on CreatorVersion
+ Comment string
+}
+
+// FileInfo returns an os.FileInfo for the FileHeader.
+func (h *FileHeader) FileInfo() os.FileInfo {
+ return headerFileInfo{h}
+}
+
+// headerFileInfo implements os.FileInfo.
+type headerFileInfo struct {
+ fh *FileHeader
+}
+
+func (fi headerFileInfo) Name() string { return path.Base(fi.fh.Name) }
+func (fi headerFileInfo) Size() int64 {
+ if fi.fh.UncompressedSize64 > 0 {
+ return int64(fi.fh.UncompressedSize64)
+ }
+ return int64(fi.fh.UncompressedSize)
+}
+func (fi headerFileInfo) IsDir() bool { return fi.Mode().IsDir() }
+func (fi headerFileInfo) ModTime() time.Time { return fi.fh.ModTime() }
+func (fi headerFileInfo) Mode() os.FileMode { return fi.fh.Mode() }
+func (fi headerFileInfo) Sys() interface{} { return fi.fh }
+
+// FileInfoHeader creates a partially-populated FileHeader from an
+// os.FileInfo.
+// Because os.FileInfo's Name method returns only the base name of
+// the file it describes, it may be necessary to modify the Name field
+// of the returned header to provide the full path name of the file.
+func FileInfoHeader(fi os.FileInfo) (*FileHeader, error) {
+ size := fi.Size()
+ fh := &FileHeader{
+ Name: fi.Name(),
+ UncompressedSize64: uint64(size),
+ }
+ fh.SetModTime(fi.ModTime())
+ fh.SetMode(fi.Mode())
+ if fh.UncompressedSize64 > uint32max {
+ fh.UncompressedSize = uint32max
+ } else {
+ fh.UncompressedSize = uint32(fh.UncompressedSize64)
+ }
+ return fh, nil
+}
+
+type directoryEnd struct {
+ diskNbr uint32 // unused
+ dirDiskNbr uint32 // unused
+ dirRecordsThisDisk uint64 // unused
+ directoryRecords uint64
+ directorySize uint64
+ directoryOffset uint64 // relative to file
+ commentLen uint16
+ comment string
+}
+
+// msDosTimeToTime converts an MS-DOS date and time into a time.Time.
+// The resolution is 2s.
+// See: http://msdn.microsoft.com/en-us/library/ms724247(v=VS.85).aspx
+func msDosTimeToTime(dosDate, dosTime uint16) time.Time {
+ return time.Date(
+ // date bits 0-4: day of month; 5-8: month; 9-15: years since 1980
+ int(dosDate>>9+1980),
+ time.Month(dosDate>>5&0xf),
+ int(dosDate&0x1f),
+
+ // time bits 0-4: second/2; 5-10: minute; 11-15: hour
+ int(dosTime>>11),
+ int(dosTime>>5&0x3f),
+ int(dosTime&0x1f*2),
+ 0, // nanoseconds
+
+ time.UTC,
+ )
+}
+
+// timeToMsDosTime converts a time.Time to an MS-DOS date and time.
+// The resolution is 2s.
+// See: http://msdn.microsoft.com/en-us/library/ms724274(v=VS.85).aspx
+func timeToMsDosTime(t time.Time) (fDate uint16, fTime uint16) {
+ t = t.In(time.UTC)
+ fDate = uint16(t.Day() + int(t.Month())<<5 + (t.Year()-1980)<<9)
+ fTime = uint16(t.Second()/2 + t.Minute()<<5 + t.Hour()<<11)
+ return
+}
+
+// ModTime returns the modification time in UTC.
+// The resolution is 2s.
+func (h *FileHeader) ModTime() time.Time {
+ return msDosTimeToTime(h.ModifiedDate, h.ModifiedTime)
+}
+
+// SetModTime sets the ModifiedTime and ModifiedDate fields to the given time in UTC.
+// The resolution is 2s.
+func (h *FileHeader) SetModTime(t time.Time) {
+ h.ModifiedDate, h.ModifiedTime = timeToMsDosTime(t)
+}
+
+const (
+ // Unix constants. The specification doesn't mention them,
+ // but these seem to be the values agreed on by tools.
+ s_IFMT = 0xf000
+ s_IFSOCK = 0xc000
+ s_IFLNK = 0xa000
+ s_IFREG = 0x8000
+ s_IFBLK = 0x6000
+ s_IFDIR = 0x4000
+ s_IFCHR = 0x2000
+ s_IFIFO = 0x1000
+ s_ISUID = 0x800
+ s_ISGID = 0x400
+ s_ISVTX = 0x200
+
+ msdosDir = 0x10
+ msdosReadOnly = 0x01
+)
+
+// Mode returns the permission and mode bits for the FileHeader.
+func (h *FileHeader) Mode() (mode os.FileMode) {
+ switch h.CreatorVersion >> 8 {
+ case creatorUnix, creatorMacOSX:
+ mode = unixModeToFileMode(h.ExternalAttrs >> 16)
+ case creatorNTFS, creatorVFAT, creatorFAT:
+ mode = msdosModeToFileMode(h.ExternalAttrs)
+ }
+ if len(h.Name) > 0 && h.Name[len(h.Name)-1] == '/' {
+ mode |= os.ModeDir
+ }
+ return mode
+}
+
+// SetMode changes the permission and mode bits for the FileHeader.
+func (h *FileHeader) SetMode(mode os.FileMode) {
+ h.CreatorVersion = h.CreatorVersion&0xff | creatorUnix<<8
+ h.ExternalAttrs = fileModeToUnixMode(mode) << 16
+
+ // set MSDOS attributes too, as the original zip does.
+ if mode&os.ModeDir != 0 {
+ h.ExternalAttrs |= msdosDir
+ }
+ if mode&0200 == 0 {
+ h.ExternalAttrs |= msdosReadOnly
+ }
+}
+
+// isZip64 returns true if the file size exceeds the 32 bit limit
+func (fh *FileHeader) isZip64() bool {
+ return fh.CompressedSize64 > uint32max || fh.UncompressedSize64 > uint32max
+}
+
+func msdosModeToFileMode(m uint32) (mode os.FileMode) {
+ if m&msdosDir != 0 {
+ mode = os.ModeDir | 0777
+ } else {
+ mode = 0666
+ }
+ if m&msdosReadOnly != 0 {
+ mode &^= 0222
+ }
+ return mode
+}
+
+func fileModeToUnixMode(mode os.FileMode) uint32 {
+ var m uint32
+ switch mode & os.ModeType {
+ default:
+ m = s_IFREG
+ case os.ModeDir:
+ m = s_IFDIR
+ case os.ModeSymlink:
+ m = s_IFLNK
+ case os.ModeNamedPipe:
+ m = s_IFIFO
+ case os.ModeSocket:
+ m = s_IFSOCK
+ case os.ModeDevice:
+ if mode&os.ModeCharDevice != 0 {
+ m = s_IFCHR
+ } else {
+ m = s_IFBLK
+ }
+ }
+ if mode&os.ModeSetuid != 0 {
+ m |= s_ISUID
+ }
+ if mode&os.ModeSetgid != 0 {
+ m |= s_ISGID
+ }
+ if mode&os.ModeSticky != 0 {
+ m |= s_ISVTX
+ }
+ return m | uint32(mode&0777)
+}
+
+func unixModeToFileMode(m uint32) os.FileMode {
+ mode := os.FileMode(m & 0777)
+ switch m & s_IFMT {
+ case s_IFBLK:
+ mode |= os.ModeDevice
+ case s_IFCHR:
+ mode |= os.ModeDevice | os.ModeCharDevice
+ case s_IFDIR:
+ mode |= os.ModeDir
+ case s_IFIFO:
+ mode |= os.ModeNamedPipe
+ case s_IFLNK:
+ mode |= os.ModeSymlink
+ case s_IFREG:
+ // nothing to do
+ case s_IFSOCK:
+ mode |= os.ModeSocket
+ }
+ if m&s_ISGID != 0 {
+ mode |= os.ModeSetgid
+ }
+ if m&s_ISUID != 0 {
+ mode |= os.ModeSetuid
+ }
+ if m&s_ISVTX != 0 {
+ mode |= os.ModeSticky
+ }
+ return mode
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-17 20:29:54 +0000