Alexey Khit
111 lines
2.1 KiB
Go
111 lines
2.1 KiB
Go
package bits
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type Reader struct {
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EOF bool // if end of buffer raised during reading
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buf []byte // total buf
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byte byte // current byte
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bits byte // bits left in byte
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pos int // current pos in buf
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}
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func NewReader(b []byte) *Reader {
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return &Reader{buf: b}
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}
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//goland:noinspection GoStandardMethods
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func (r *Reader) ReadByte() byte {
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if r.bits != 0 {
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return r.ReadBits8(8)
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}
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if r.pos >= len(r.buf) {
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r.EOF = true
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return 0
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}
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b := r.buf[r.pos]
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r.pos++
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return b
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}
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func (r *Reader) ReadUint16() uint16 {
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if r.bits != 0 {
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return r.ReadBits16(16)
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}
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return uint16(r.ReadByte())<<8 | uint16(r.ReadByte())
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}
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func (r *Reader) ReadUint24() uint32 {
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if r.bits != 0 {
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return r.ReadBits(24)
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}
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return uint32(r.ReadByte())<<16 | uint32(r.ReadByte())<<8 | uint32(r.ReadByte())
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}
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func (r *Reader) ReadUint32() uint32 {
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if r.bits != 0 {
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return r.ReadBits(32)
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}
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return uint32(r.ReadByte())<<24 | uint32(r.ReadByte())<<16 | uint32(r.ReadByte())<<8 | uint32(r.ReadByte())
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}
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func (r *Reader) ReadBit() byte {
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if r.bits == 0 {
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r.byte = r.ReadByte()
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r.bits = 7
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} else {
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r.bits--
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}
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return (r.byte >> r.bits) & 0b1
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}
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func (r *Reader) ReadBits(n byte) (res uint32) {
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for i := n - 1; i != 255; i-- {
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res |= uint32(r.ReadBit()) << i
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}
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return
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}
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func (r *Reader) ReadBits8(n byte) (res uint8) {
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for i := n - 1; i != 255; i-- {
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res |= r.ReadBit() << i
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}
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return
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}
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func (r *Reader) ReadBits16(n byte) (res uint16) {
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for i := n - 1; i != 255; i-- {
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res |= uint16(r.ReadBit()) << i
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}
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return
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}
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func (r *Reader) ReadBits64(n byte) (res uint64) {
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for i := n - 1; i != 255; i-- {
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res |= uint64(r.ReadBit()) << i
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}
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return
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}
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// ReadUEGolomb - ReadExponentialGolomb (unsigned)
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func (r *Reader) ReadUEGolomb() uint32 {
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var size byte
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for size = 0; size < 32; size++ {
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if b := r.ReadBit(); b != 0 || r.EOF {
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break
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}
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}
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return r.ReadBits(size) + (1 << size) - 1
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}
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// ReadSEGolomb - ReadSignedExponentialGolomb
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func (r *Reader) ReadSEGolomb() int32 {
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if b := r.ReadUEGolomb(); b%2 == 0 {
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return -int32(b >> 1)
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} else {
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return int32(b >> 1)
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}
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}
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