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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 ZIP64 or disk spanning.
*/
package zip
import (
"errors"
"os"
"time"
)
// Compression methods.
const (
Store uint16 = 0
Deflate uint16 = 8
)
const (
fileHeaderSignature = 0x04034b50
directoryHeaderSignature = 0x02014b50
directoryEndSignature = 0x06054b50
fileHeaderLen = 30 // + filename + extra
directoryHeaderLen = 46 // + filename + extra + comment
directoryEndLen = 22 // + comment
dataDescriptorLen = 12
// Constants for the first byte in CreatorVersion
creatorFAT = 0
creatorUnix = 3
creatorNTFS = 11
creatorVFAT = 14
creatorMacOSX = 19
)
type FileHeader struct {
Name string
CreatorVersion uint16
ReaderVersion uint16
Flags uint16
Method uint16
ModifiedTime uint16 // MS-DOS time
ModifiedDate uint16 // MS-DOS date
CRC32 uint32
CompressedSize uint32
UncompressedSize uint32
Extra []byte
ExternalAttrs uint32 // Meaning depends on CreatorVersion
Comment string
}
// FileInfo returns an os.FileInfo for the FileHeader.
func (fh *FileHeader) FileInfo() os.FileInfo {
return headerFileInfo{fh}
}
// headerFileInfo implements os.FileInfo.
type headerFileInfo struct {
fh *FileHeader
}
func (fi headerFileInfo) Name() string { return fi.fh.Name }
func (fi headerFileInfo) Size() int64 { 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() }
// FileInfoHeader creates a partially-populated FileHeader from an
// os.FileInfo.
func FileInfoHeader(fi os.FileInfo) (*FileHeader, error) {
size := fi.Size()
if size > (1<<32 - 1) {
return nil, errors.New("zip: file over 4GB")
}
fh := &FileHeader{
Name: fi.Name(),
UncompressedSize: uint32(size),
}
fh.SetModTime(fi.ModTime())
fh.SetMode(fi.Mode())
return fh, nil
}
type directoryEnd struct {
diskNbr uint16 // unused
dirDiskNbr uint16 // unused
dirRecordsThisDisk uint16 // unused
directoryRecords uint16
directorySize uint32
directoryOffset uint32 // relative to file
commentLen uint16
comment string
}
func recoverError(errp *error) {
if e := recover(); e != nil {
if err, ok := e.(error); ok {
*errp = err
return
}
panic(e)
}
}
// 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.
// 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.
// The resolution is 2s.
func (h *FileHeader) SetModTime(t time.Time) {
h.ModifiedDate, h.ModifiedTime = timeToMsDosTime(t)
}
// traditional names for Unix constants
const (
s_IFMT = 0xf000
s_IFDIR = 0x4000
s_IFREG = 0x8000
s_ISUID = 0x800
s_ISGID = 0x400
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
}
}
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
if mode&os.ModeDir != 0 {
m = s_IFDIR
} else {
m = s_IFREG
}
if mode&os.ModeSetuid != 0 {
m |= s_ISUID
}
if mode&os.ModeSetgid != 0 {
m |= s_ISGID
}
return m | uint32(mode&0777)
}
func unixModeToFileMode(m uint32) os.FileMode {
var mode os.FileMode
if m&s_IFMT == s_IFDIR {
mode |= os.ModeDir
}
if m&s_ISGID != 0 {
mode |= os.ModeSetgid
}
if m&s_ISUID != 0 {
mode |= os.ModeSetuid
}
return mode | os.FileMode(m&0777)
}
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