func()

in writer.go [77:207]

• 109 lines of code
• 20 McCabe index (conditional complexity)

func (w *Writer) Close() error {
	if w.last != nil && !w.last.closed {
		if err := w.last.close(); err != nil {
			return err
		}
		w.last = nil
	}
	if w.closed {
		return errors.New("zip: writer closed twice")
	}
	w.closed = true

	// write central directory
	start := w.cw.count
	for _, h := range w.dir {
		var buf [directoryHeaderLen]byte
		b := writeBuf(buf[:])
		b.uint32(uint32(directoryHeaderSignature))
		b.uint16(h.CreatorVersion)
		b.uint16(h.ReaderVersion)
		b.uint16(h.Flags)
		b.uint16(h.Method)
		b.uint16(h.ModifiedTime)
		b.uint16(h.ModifiedDate)
		b.uint32(h.CRC32)
		if h.isZip64() || h.offset >= uint32max {
			// the file needs a zip64 header. store maxint in both
			// 32 bit size fields (and offset later) to signal that the
			// zip64 extra header should be used.
			b.uint32(uint32max) // compressed size
			b.uint32(uint32max) // uncompressed size

			// append a zip64 extra block to Extra
			var buf [28]byte // 2x uint16 + 3x uint64
			eb := writeBuf(buf[:])
			eb.uint16(zip64ExtraID)
			eb.uint16(24) // size = 3x uint64
			eb.uint64(h.UncompressedSize64)
			eb.uint64(h.CompressedSize64)
			eb.uint64(h.offset)
			h.Extra = append(h.Extra, buf[:]...)
		} else {
			b.uint32(h.CompressedSize)
			b.uint32(h.UncompressedSize)
		}

		b.uint16(uint16(len(h.Name)))
		b.uint16(uint16(len(h.Extra)))
		b.uint16(uint16(len(h.Comment)))
		b = b[4:] // skip disk number start and internal file attr (2x uint16)
		b.uint32(h.ExternalAttrs)
		if h.offset > uint32max {
			b.uint32(uint32max)
		} else {
			b.uint32(uint32(h.offset))
		}
		if _, err := w.cw.Write(buf[:]); err != nil {
			return err
		}
		if _, err := io.WriteString(w.cw, h.Name); err != nil {
			return err
		}
		if _, err := w.cw.Write(h.Extra); err != nil {
			return err
		}
		if _, err := io.WriteString(w.cw, h.Comment); err != nil {
			return err
		}
	}
	end := w.cw.count

	records := uint64(len(w.dir))
	size := uint64(end - start)
	offset := uint64(start)

	if f := w.testHookCloseSizeOffset; f != nil {
		f(size, offset)
	}

	if records >= uint16max || size >= uint32max || offset >= uint32max {
		var buf [directory64EndLen + directory64LocLen]byte
		b := writeBuf(buf[:])

		// zip64 end of central directory record
		b.uint32(directory64EndSignature)
		b.uint64(directory64EndLen - 12) // length minus signature (uint32) and length fields (uint64)
		b.uint16(zipVersion45)           // version made by
		b.uint16(zipVersion45)           // version needed to extract
		b.uint32(0)                      // number of this disk
		b.uint32(0)                      // number of the disk with the start of the central directory
		b.uint64(records)                // total number of entries in the central directory on this disk
		b.uint64(records)                // total number of entries in the central directory
		b.uint64(size)                   // size of the central directory
		b.uint64(offset)                 // offset of start of central directory with respect to the starting disk number

		// zip64 end of central directory locator
		b.uint32(directory64LocSignature)
		b.uint32(0)           // number of the disk with the start of the zip64 end of central directory
		b.uint64(uint64(end)) // relative offset of the zip64 end of central directory record
		b.uint32(1)           // total number of disks

		if _, err := w.cw.Write(buf[:]); err != nil {
			return err
		}

		// store max values in the regular end record to signal
		// that the zip64 values should be used instead
		records = uint16max
		size = uint32max
		offset = uint32max
	}

	// write end record
	var buf [directoryEndLen]byte
	b := writeBuf(buf[:])
	b.uint32(uint32(directoryEndSignature))
	b = b[4:]                        // skip over disk number and first disk number (2x uint16)
	b.uint16(uint16(records))        // number of entries this disk
	b.uint16(uint16(records))        // number of entries total
	b.uint32(uint32(size))           // size of directory
	b.uint32(uint32(offset))         // start of directory
	b.uint16(uint16(len(w.comment))) // byte size of EOCD comment
	if _, err := w.cw.Write(buf[:]); err != nil {
		return err
	}
	if _, err := io.WriteString(w.cw, w.comment); err != nil {
		return err
	}

	return w.cw.w.(*bufio.Writer).Flush()
}