13 "github.com/edsrzf/mmap-go"
16 // The packed format is an 8 byte integer of the number of ranges. Then 20
17 // bytes per range, consisting of 4 byte packed IP being the lower bound IP of
18 // the range, then 4 bytes of the upper, inclusive bound, 8 bytes for the
19 // offset of the description from the end of the packed ranges, and 4 bytes
20 // for the length of the description. After these packed ranges, are the
21 // concatenated descriptions.
24 packedRangesOffset = 8
28 func (ipl *IPList) WritePacked(w io.Writer) (err error) {
29 descOffsets := make(map[string]int64, len(ipl.ranges))
30 descs := make([]string, 0, len(ipl.ranges))
32 // This is a little monadic, no?
33 write := func(b []byte, expectedLen int) {
47 binary.LittleEndian.PutUint64(b[:], uint64(len(ipl.ranges)))
49 for _, r := range ipl.ranges {
50 write(r.First.To16(), 16)
51 write(r.Last.To16(), 16)
52 descOff, ok := descOffsets[r.Description]
55 descOffsets[r.Description] = descOff
56 descs = append(descs, r.Description)
57 nextOffset += int64(len(r.Description))
59 binary.LittleEndian.PutUint64(b[:], uint64(descOff))
61 binary.LittleEndian.PutUint32(b[:], uint32(len(r.Description)))
64 for _, d := range descs {
65 write([]byte(d), len(d))
70 func NewFromPacked(b []byte) PackedIPList {
71 ret := PackedIPList(b)
72 minLen := packedRangesOffset + ret.len()*packedRangeLen
74 panic(fmt.Sprintf("packed len %d < %d", len(b), minLen))
79 type PackedIPList []byte
81 var _ Ranger = PackedIPList{}
83 func (pil PackedIPList) len() int {
84 return int(binary.LittleEndian.Uint64(pil[:8]))
87 func (pil PackedIPList) NumRanges() int {
91 func (pil PackedIPList) getFirst(i int) net.IP {
92 off := packedRangesOffset + packedRangeLen*i
93 return net.IP(pil[off : off+16])
96 func (pil PackedIPList) getRange(i int) (ret Range) {
97 rOff := packedRangesOffset + packedRangeLen*i
98 last := pil[rOff+16 : rOff+32]
99 descOff := int(binary.LittleEndian.Uint64(pil[rOff+32:]))
100 descLen := int(binary.LittleEndian.Uint32(pil[rOff+40:]))
101 descOff += packedRangesOffset + packedRangeLen*pil.len()
105 string(pil[descOff : descOff+descLen]),
110 func (pil PackedIPList) Lookup(ip net.IP) (r Range, ok bool) {
115 return lookup(pil.getFirst, pil.getRange, pil.len(), ip16)
118 type closerFunc func() error
120 func (me closerFunc) Close() error {
124 func MMapPackedFile(filename string) (
131 f, err := os.Open(filename)
136 mm, err := mmap.Map(f, mmap.RDONLY, 0)
143 }{NewFromPacked(mm), closerFunc(mm.Unmap)}