func readVarint(r *io.SectionReader, offset int64) (v int64, n int, err error) {
var buf [16]byte // 109 bits should be enough for everybody.
_, err = r.ReadAt(buf[:], offset)
if err == io.EOF || err == io.ErrUnexpectedEOF {
err = nil
}
if err != nil {
return
}
u, n := binary.Uvarint(buf[:])
v = int64(u)
return
}
func (pk *PackReader) checkIdxMagic(idx *io.SectionReader) (err error) {
var buf [idxHeaderSize]byte
_, err = idx.ReadAt(buf[:], 0)
if err != nil {
return
}
magic := [4]byte{buf[0], buf[1], buf[2], buf[3]}
if magic != ([4]byte{'\xff', 't', 'O', 'c'}) {
return errBadIdxMagic
}
for i := range pk.idxFanout {
pk.idxFanout[i] = binary.BigEndian.Uint32(buf[8+4*i:])
}
return nil
}
func checkPackMagic(pack *io.SectionReader) (version, count uint32, err error) {
var buf [12]byte
_, err = pack.ReadAt(buf[:], 0)
if err != nil {
return
}
magic := [4]byte{buf[0], buf[1], buf[2], buf[3]}
if magic != ([4]byte{'P', 'A', 'C', 'K'}) {
err = errBadPackMagic
}
version = binary.BigEndian.Uint32(buf[4:8])
if version != 2 {
err = errUnsupportedPackVersion
}
count = binary.BigEndian.Uint32(buf[4:8])
return
}
// readVaroffset reads the pseudo-varint used to encode offsets for delta bases.
// It is a big-endian form: 1|a0, ..., 1|a_{n-1}, 0|a_n.
// representing:
// (a0+1)<<7*n + ... + (a_{n-1}+1)<<7 + a_n
func readVaroffset(r *io.SectionReader, offset int64) (v int64, n int, err error) {
var buf [16]byte // 109 bits should be enough for everybody.
n, err = r.ReadAt(buf[:], offset)
if err == io.EOF || err == io.ErrUnexpectedEOF {
err = nil
}
if err != nil {
return
}
u := uint64(0)
for i, b := range buf[:n] {
if i > 0 {
u++
}
u <<= 7
u |= uint64(b &^ 0x80)
if b&0x80 == 0 {
return int64(u), i + 1, nil
}
}
return int64(u), len(buf), io.ErrUnexpectedEOF
}
func cmapParser(_ SFNT, r *io.SectionReader) Table {
t := new(Cmap)
header := CmapHeader{}
if err := binary.Read(r, binary.BigEndian, &header); err != nil {
return nil
}
t.Version = header.Version
numTables := header.NumTables
encodingRecord := make([]EncodingRecord, numTables)
if err := binary.Read(r, binary.BigEndian, encodingRecord); err != nil {
return nil
}
t.Subtable = make([]CmapSubtable, numTables)
for i, v := range encodingRecord {
pid, eid, offset := v.PlatformID, v.EncodingID, int64(v.Offset)
format := make([]byte, 8)
r.ReadAt(format, offset)
var length int64
switch binary.BigEndian.Uint16(format[:2]) {
case 0, 2, 4, 6:
length = int64(binary.BigEndian.Uint16(format[2:4]))
break
case 8, 10, 12, 13:
length = int64(binary.BigEndian.Uint32(format[4:8]))
break
case 14:
length = int64(binary.BigEndian.Uint32(format[2:6]))
break
default:
return nil
}
sr := io.NewSectionReader(r, offset, length)
t.Subtable[i] = CmapSubtable{pid, eid, &SubtableReader{sr}}
}
return Table(t)
}