package zip

Import Path
	archive/zip (on golang.org and go.dev)

Dependency Relation
	imports 15 packages, and imported by 0 packages

Involved Source Files

	      reader.go
	      register.go
	   d➜ struct.go
		Package zip provides support for reading and writing ZIP archives.

		See: https://www.pkware.com/appnote

		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.

	      writer.go
Code Examples

	Reader
		package main
		
		import (
			"archive/zip"
			"fmt"
			"io"
			"log"
			"os"
		)
		
		func main() {
			// Open a zip archive for reading.
			r, err := zip.OpenReader("testdata/readme.zip")
			if err != nil {
				log.Fatal(err)
			}
			defer r.Close()
		
			// Iterate through the files in the archive,
			// printing some of their contents.
			for _, f := range r.File {
				fmt.Printf("Contents of %s:\n", f.Name)
				rc, err := f.Open()
				if err != nil {
					log.Fatal(err)
				}
				_, err = io.CopyN(os.Stdout, rc, 68)
				if err != nil {
					log.Fatal(err)
				}
				rc.Close()
				fmt.Println()
			}
		}


	Writer
		package main
		
		import (
			"archive/zip"
			"bytes"
			"log"
		)
		
		func main() {
			// Create a buffer to write our archive to.
			buf := new(bytes.Buffer)
		
			// Create a new zip archive.
			w := zip.NewWriter(buf)
		
			// Add some files to the archive.
			var files = []struct {
				Name, Body string
			}{
				{"readme.txt", "This archive contains some text files."},
				{"gopher.txt", "Gopher names:\nGeorge\nGeoffrey\nGonzo"},
				{"todo.txt", "Get animal handling licence.\nWrite more examples."},
			}
			for _, file := range files {
				f, err := w.Create(file.Name)
				if err != nil {
					log.Fatal(err)
				}
				_, err = f.Write([]byte(file.Body))
				if err != nil {
					log.Fatal(err)
				}
			}
		
			// Make sure to check the error on Close.
			err := w.Close()
			if err != nil {
				log.Fatal(err)
			}
		}


	Writer_RegisterCompressor
		package main
		
		import (
			"archive/zip"
			"bytes"
			"compress/flate"
			"io"
		)
		
		func main() {
			// Override the default Deflate compressor with a higher compression level.
		
			// Create a buffer to write our archive to.
			buf := new(bytes.Buffer)
		
			// Create a new zip archive.
			w := zip.NewWriter(buf)
		
			// Register a custom Deflate compressor.
			w.RegisterCompressor(zip.Deflate, func(out io.Writer) (io.WriteCloser, error) {
				return flate.NewWriter(out, flate.BestCompression)
			})
		
			// Proceed to add files to w.
		}


Package-Level Type Names (total 7)

	/* sort by: alphabet | popularity */
	 type Compressor (func)
		A Compressor returns a new compressing writer, writing to w.
		The WriteCloser's Close method must be used to flush pending data to w.
		The Compressor itself must be safe to invoke from multiple goroutines
		simultaneously, but each returned writer will be used only by
		one goroutine at a time.

		As Inputs Of (at least 2)
			func RegisterCompressor(method uint16, comp Compressor)
			func (*Writer).RegisterCompressor(method uint16, comp Compressor)

	 type Decompressor (func)
		A Decompressor returns a new decompressing reader, reading from r.
		The ReadCloser's Close method must be used to release associated resources.
		The Decompressor itself must be safe to invoke from multiple goroutines
		simultaneously, but each returned reader will be used only by
		one goroutine at a time.

		As Inputs Of (at least 2)
			func RegisterDecompressor(method uint16, dcomp Decompressor)
			func (*Reader).RegisterDecompressor(method uint16, dcomp Decompressor)

	 type File (struct)
		A File is a single file in a ZIP archive.
		The file information is in the embedded FileHeader.
		The file content can be accessed by calling Open.

		Fields (total 18)
			FileHeader FileHeader
			FileHeader.CRC32 uint32
			FileHeader.Comment string
				Comment is any arbitrary user-defined string shorter than 64KiB.

			FileHeader.CompressedSize uint32
				// Deprecated: Use CompressedSize64 instead.

			FileHeader.CompressedSize64 uint64
			FileHeader.CreatorVersion uint16
			FileHeader.ExternalAttrs uint32
				// Meaning depends on CreatorVersion

			FileHeader.Extra []byte
			FileHeader.Flags uint16
			FileHeader.Method uint16
				Method is the compression method. If zero, Store is used.

			FileHeader.Modified time.Time
				Modified is the modified time of the file.

				When reading, an extended timestamp is preferred over the legacy MS-DOS
				date field, and the offset between the times is used as the timezone.
				If only the MS-DOS date is present, the timezone is assumed to be UTC.

				When writing, an extended timestamp (which is timezone-agnostic) is
				always emitted. The legacy MS-DOS date field is encoded according to the
				location of the Modified time.

			FileHeader.ModifiedDate uint16
				// Deprecated: Legacy MS-DOS time; use Modified instead.

			FileHeader.ModifiedTime uint16
				// Deprecated: Legacy MS-DOS date; use Modified instead.

			FileHeader.Name string
				Name is the name of the file.

				It must be a relative path, not start with a drive letter (such as "C:"),
				and must use forward slashes instead of back slashes. A trailing slash
				indicates that this file is a directory and should have no data.

				When reading zip files, the Name field is populated from
				the zip file directly and is not validated for correctness.
				It is the caller's responsibility to sanitize it as
				appropriate, including canonicalizing slash directions,
				validating that paths are relative, and preventing path
				traversal through filenames ("../../../").

			FileHeader.NonUTF8 bool
				NonUTF8 indicates that Name and Comment are not encoded in UTF-8.

				By specification, the only other encoding permitted should be CP-437,
				but historically many ZIP readers interpret Name and Comment as whatever
				the system's local character encoding happens to be.

				This flag should only be set if the user intends to encode a non-portable
				ZIP file for a specific localized region. Otherwise, the Writer
				automatically sets the ZIP format's UTF-8 flag for valid UTF-8 strings.

			FileHeader.ReaderVersion uint16
			FileHeader.UncompressedSize uint32
				// Deprecated: Use UncompressedSize64 instead.

			FileHeader.UncompressedSize64 uint64
		Methods (total 8)
			(*T) DataOffset() (offset int64, err error)
				DataOffset returns the offset of the file's possibly-compressed
				data, relative to the beginning of the zip file.

				Most callers should instead use Open, which transparently
				decompresses data and verifies checksums.

			(*T) FileInfo() fs.FileInfo
				FileInfo returns an fs.FileInfo for the FileHeader.

			(*T) ModTime() time.Time
				ModTime returns the modification time in UTC using the legacy
				ModifiedDate and ModifiedTime fields.

				Deprecated: Use Modified instead.

			(*T) Mode() (mode fs.FileMode)
				Mode returns the permission and mode bits for the FileHeader.

			(*T) Open() (io.ReadCloser, error)
				Open returns a ReadCloser that provides access to the File's contents.
				Multiple files may be read concurrently.

			(*T) OpenRaw() (io.Reader, error)
				OpenRaw returns a Reader that provides access to the File's contents without
				decompression.

			(*T) SetModTime(t time.Time)
				SetModTime sets the Modified, ModifiedTime, and ModifiedDate fields
				to the given time in UTC.

				Deprecated: Use Modified instead.

			(*T) SetMode(mode fs.FileMode)
				SetMode changes the permission and mode bits for the FileHeader.

		As Inputs Of (at least one exported)
			func (*Writer).Copy(f *File) error

	 type FileHeader (struct)
		FileHeader describes a file within a zip file.
		See the zip spec for details.

		Fields (total 17)
			CRC32 uint32
			Comment string
				Comment is any arbitrary user-defined string shorter than 64KiB.

			CompressedSize uint32
				// Deprecated: Use CompressedSize64 instead.

			CompressedSize64 uint64
			CreatorVersion uint16
			ExternalAttrs uint32
				// Meaning depends on CreatorVersion

			Extra []byte
			Flags uint16
			Method uint16
				Method is the compression method. If zero, Store is used.

			Modified time.Time
				Modified is the modified time of the file.

				When reading, an extended timestamp is preferred over the legacy MS-DOS
				date field, and the offset between the times is used as the timezone.
				If only the MS-DOS date is present, the timezone is assumed to be UTC.

				When writing, an extended timestamp (which is timezone-agnostic) is
				always emitted. The legacy MS-DOS date field is encoded according to the
				location of the Modified time.

			ModifiedDate uint16
				// Deprecated: Legacy MS-DOS time; use Modified instead.

			ModifiedTime uint16
				// Deprecated: Legacy MS-DOS date; use Modified instead.

			Name string
				Name is the name of the file.

				It must be a relative path, not start with a drive letter (such as "C:"),
				and must use forward slashes instead of back slashes. A trailing slash
				indicates that this file is a directory and should have no data.

				When reading zip files, the Name field is populated from
				the zip file directly and is not validated for correctness.
				It is the caller's responsibility to sanitize it as
				appropriate, including canonicalizing slash directions,
				validating that paths are relative, and preventing path
				traversal through filenames ("../../../").

			NonUTF8 bool
				NonUTF8 indicates that Name and Comment are not encoded in UTF-8.

				By specification, the only other encoding permitted should be CP-437,
				but historically many ZIP readers interpret Name and Comment as whatever
				the system's local character encoding happens to be.

				This flag should only be set if the user intends to encode a non-portable
				ZIP file for a specific localized region. Otherwise, the Writer
				automatically sets the ZIP format's UTF-8 flag for valid UTF-8 strings.

			ReaderVersion uint16
			UncompressedSize uint32
				// Deprecated: Use UncompressedSize64 instead.

			UncompressedSize64 uint64
		Methods (total 5)
			(*T) FileInfo() fs.FileInfo
				FileInfo returns an fs.FileInfo for the FileHeader.

			(*T) ModTime() time.Time
				ModTime returns the modification time in UTC using the legacy
				ModifiedDate and ModifiedTime fields.

				Deprecated: Use Modified instead.

			(*T) Mode() (mode fs.FileMode)
				Mode returns the permission and mode bits for the FileHeader.

			(*T) SetModTime(t time.Time)
				SetModTime sets the Modified, ModifiedTime, and ModifiedDate fields
				to the given time in UTC.

				Deprecated: Use Modified instead.

			(*T) SetMode(mode fs.FileMode)
				SetMode changes the permission and mode bits for the FileHeader.

		As Outputs Of (at least one exported)
			func FileInfoHeader(fi fs.FileInfo) (*FileHeader, error)
		As Inputs Of (at least 2)
			func (*Writer).CreateHeader(fh *FileHeader) (io.Writer, error)
			func (*Writer).CreateRaw(fh *FileHeader) (io.Writer, error)

	 type ReadCloser (struct)
		A ReadCloser is a Reader that must be closed when no longer needed.

		Fields (total 3)
			Reader Reader
			Reader.Comment string
			Reader.File []*File
		Methods (total 3)
			(*T) Close() error
				Close closes the Zip file, rendering it unusable for I/O.

			(*T) Open(name string) (fs.File, error)
				Open opens the named file in the ZIP archive,
				using the semantics of fs.FS.Open:
				paths are always slash separated, with no
				leading / or ../ elements.

			(*T) RegisterDecompressor(method uint16, dcomp Decompressor)
				RegisterDecompressor registers or overrides a custom decompressor for a
				specific method ID. If a decompressor for a given method is not found,
				Reader will default to looking up the decompressor at the package level.

		Implements (at least 2)
			*T : io.Closer
			*T : io/fs.FS
		As Outputs Of (at least one exported)
			func OpenReader(name string) (*ReadCloser, error)

	 type Reader (struct)
		A Reader serves content from a ZIP archive.

		Fields (total 2)
			Comment string
			File []*File
		Methods (total 2)
			(*T) Open(name string) (fs.File, error)
				Open opens the named file in the ZIP archive,
				using the semantics of fs.FS.Open:
				paths are always slash separated, with no
				leading / or ../ elements.

			(*T) RegisterDecompressor(method uint16, dcomp Decompressor)
				RegisterDecompressor registers or overrides a custom decompressor for a
				specific method ID. If a decompressor for a given method is not found,
				Reader will default to looking up the decompressor at the package level.

		Implements (at least one exported)
			*T : io/fs.FS
		As Outputs Of (at least one exported)
			func NewReader(r io.ReaderAt, size int64) (*Reader, error)

	 type Writer (struct)
		Writer implements a zip file writer.

		Methods (total 9)
			(*T) Close() error
				Close finishes writing the zip file by writing the central directory.
				It does not close the underlying writer.

			(*T) Copy(f *File) error
				Copy copies the file f (obtained from a Reader) into w. It copies the raw
				form directly bypassing decompression, compression, and validation.

			(*T) Create(name string) (io.Writer, error)
				Create adds a file to the zip file using the provided name.
				It returns a Writer to which the file contents should be written.
				The file contents will be compressed using the Deflate method.
				The name 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. To create a directory instead of a file, add a trailing
				slash to the name.
				The file's contents must be written to the io.Writer before the next
				call to Create, CreateHeader, or Close.

			(*T) CreateHeader(fh *FileHeader) (io.Writer, error)
				CreateHeader adds a file to the zip archive using the provided FileHeader
				for the file metadata. Writer takes ownership of fh and may mutate
				its fields. The caller must not modify fh after calling CreateHeader.

				This returns a Writer to which the file contents should be written.
				The file's contents must be written to the io.Writer before the next
				call to Create, CreateHeader, CreateRaw, or Close.

			(*T) CreateRaw(fh *FileHeader) (io.Writer, error)
				CreateRaw adds a file to the zip archive using the provided FileHeader and
				returns a Writer to which the file contents should be written. The file's
				contents must be written to the io.Writer before the next call to Create,
				CreateHeader, CreateRaw, or Close.

				In contrast to CreateHeader, the bytes passed to Writer are not compressed.

			(*T) Flush() error
				Flush flushes any buffered data to the underlying writer.
				Calling Flush is not normally necessary; calling Close is sufficient.

			(*T) RegisterCompressor(method uint16, comp Compressor)
				RegisterCompressor registers or overrides a custom compressor for a specific
				method ID. If a compressor for a given method is not found, Writer will
				default to looking up the compressor at the package level.

			(*T) SetComment(comment string) error
				SetComment sets the end-of-central-directory comment field.
				It can only be called before Close.

			(*T) SetOffset(n int64)
				SetOffset sets the offset of the beginning of the zip data within the
				underlying writer. It should be used when the zip data is appended to an
				existing file, such as a binary executable.
				It must be called before any data is written.

		Implements (at least one exported)
			*T : io.Closer
		As Outputs Of (at least one exported)
			func NewWriter(w io.Writer) *Writer


Package-Level Functions (total 6)

	 func FileInfoHeader(fi fs.FileInfo) (*FileHeader, error)
		FileInfoHeader creates a partially-populated FileHeader from an
		fs.FileInfo.
		Because fs.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.
		If compression is desired, callers should set the FileHeader.Method
		field; it is unset by default.

	 func NewReader(r io.ReaderAt, size int64) (*Reader, error)
		NewReader returns a new Reader reading from r, which is assumed to
		have the given size in bytes.

	 func NewWriter(w io.Writer) *Writer
		NewWriter returns a new Writer writing a zip file to w.

	 func OpenReader(name string) (*ReadCloser, error)
		OpenReader will open the Zip file specified by name and return a ReadCloser.

	 func RegisterCompressor(method uint16, comp Compressor)
		RegisterCompressor registers custom compressors for a specified method ID.
		The common methods Store and Deflate are built in.

	 func RegisterDecompressor(method uint16, dcomp Decompressor)
		RegisterDecompressor allows custom decompressors for a specified method ID.
		The common methods Store and Deflate are built in.


Package-Level Variables (total 3)

	  var ErrAlgorithm error
	  var ErrChecksum error
	  var ErrFormat error
Package-Level Constants (total 2)

	const Deflate uint16 = 8 // DEFLATE compressed
		Compression methods.

	const Store uint16 = 0 // no compression
		Compression methods.

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