forked from quic-go/quic-go
104 lines
2.5 KiB
Go
104 lines
2.5 KiB
Go
package utils
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import (
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"bytes"
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"encoding/binary"
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"io"
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)
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// ReadUintN reads N bytes
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// ToDo: add tests
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func ReadUintN(b io.ByteReader, length uint8) (uint64, error) {
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var res uint64
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for i := uint8(0); i < length; i++ {
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bt, err := b.ReadByte()
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if err != nil {
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return 0, err
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}
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res ^= uint64(bt) << (i * 8)
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}
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return res, nil
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}
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// ReadUint32 reads a uint32
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func ReadUint32(b io.ByteReader) (uint32, error) {
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slice, err := readNBytes(b, 4)
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if err != nil {
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return 0, err
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}
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return binary.LittleEndian.Uint32(slice), nil
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}
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// ReadUint32BigEndian reads a uint32 Big Endian
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func ReadUint32BigEndian(b io.ByteReader) (uint32, error) {
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slice, err := readNBytes(b, 4)
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if err != nil {
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return 0, err
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}
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return binary.BigEndian.Uint32(slice), nil
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}
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// ReadUint16 reads a uint16
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func ReadUint16(b io.ByteReader) (uint16, error) {
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slice, err := readNBytes(b, 2)
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if err != nil {
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return 0, err
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}
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return binary.LittleEndian.Uint16(slice), nil
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}
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func readNBytes(b io.ByteReader, n int) ([]byte, error) {
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slice := make([]byte, n, n)
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var val uint8
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var err error
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for i := 0; i < n; i++ {
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val, err = b.ReadByte()
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if err != nil {
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return []byte{}, err
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}
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slice[i] = val
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}
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return slice, nil
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}
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// WriteUint64 writes a uint64
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func WriteUint64(b *bytes.Buffer, i uint64) {
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b.WriteByte(uint8(i & 0xff))
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b.WriteByte(uint8((i >> 8) & 0xff))
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b.WriteByte(uint8((i >> 16) & 0xff))
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b.WriteByte(uint8((i >> 24) & 0xff))
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b.WriteByte(uint8((i >> 32) & 0xff))
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b.WriteByte(uint8((i >> 40) & 0xff))
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b.WriteByte(uint8((i >> 48) & 0xff))
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b.WriteByte(uint8(i >> 56))
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}
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// WriteUint32 writes a uint32
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func WriteUint32(b *bytes.Buffer, i uint32) {
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b.WriteByte(uint8(i & 0xff))
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b.WriteByte(uint8((i >> 8) & 0xff))
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b.WriteByte(uint8((i >> 16) & 0xff))
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b.WriteByte(uint8((i >> 24) & 0xff))
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}
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// WriteUint32BigEndian writes a uint32
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func WriteUint32BigEndian(b *bytes.Buffer, i uint32) {
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b.WriteByte(uint8((i >> 24) & 0xff))
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b.WriteByte(uint8((i >> 16) & 0xff))
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b.WriteByte(uint8((i >> 8) & 0xff))
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b.WriteByte(uint8(i & 0xff))
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}
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// WriteUint16 writes a uint16
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func WriteUint16(b *bytes.Buffer, i uint16) {
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b.WriteByte(uint8(i & 0xff))
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b.WriteByte(uint8((i >> 8) & 0xff))
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}
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// Uint32Slice attaches the methods of sort.Interface to []uint32, sorting in increasing order.
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type Uint32Slice []uint32
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func (s Uint32Slice) Len() int { return len(s) }
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func (s Uint32Slice) Less(i, j int) bool { return s[i] < s[j] }
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func (s Uint32Slice) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
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