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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"
import "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
creatorUnix = 3
)
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
}
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.Time{
// date bits 0-4: day of month; 5-8: month; 9-15: years since 1980
Year: int64(dosDate>>9 + 1980),
Month: int(dosDate >> 5 & 0xf),
Day: int(dosDate & 0x1f),
// time bits 0-4: second/2; 5-10: minute; 11-15: hour
Hour: int(dosTime >> 11),
Minute: int(dosTime >> 5 & 0x3f),
Second: int(dosTime & 0x1f * 2),
}
}
// Mtime_ns returns the modified time in ns since epoch.
// The resolution is 2s.
func (h *FileHeader) Mtime_ns() int64 {
t := msDosTimeToTime(h.ModifiedDate, h.ModifiedTime)
return t.Seconds() * 1e9
}
// Mode returns the permission and mode bits for the FileHeader.
// An error is returned in case the information is not available.
func (h *FileHeader) Mode() (mode uint32, err error) {
if h.CreatorVersion>>8 == creatorUnix {
return h.ExternalAttrs >> 16, nil
}
return 0, errors.New("file mode not available")
}
// SetMode changes the permission and mode bits for the FileHeader.
func (h *FileHeader) SetMode(mode uint32) {
h.CreatorVersion = h.CreatorVersion&0xff | creatorUnix<<8
h.ExternalAttrs = mode << 16
}
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