mirror of
https://github.com/mumble-voip/grumble.git
synced 2025-12-19 21:59:59 -08:00
326 lines
7.2 KiB
Go
326 lines
7.2 KiB
Go
// Grumble - an implementation of Murmur in Go
|
|
// Copyright (c) 2010 The Grumble Authors
|
|
// The use of this source code is goverened by a BSD-style
|
|
// license that can be found in the LICENSE-file.
|
|
|
|
package packetdata
|
|
|
|
import (
|
|
"math"
|
|
)
|
|
|
|
type PacketData struct {
|
|
Buf []byte
|
|
offset int
|
|
maxsize int
|
|
overshoot int
|
|
ok bool
|
|
}
|
|
|
|
func New(buf []byte) (pds *PacketData) {
|
|
pds = new(PacketData)
|
|
pds.Buf = buf
|
|
pds.maxsize = len(buf)
|
|
pds.ok = true
|
|
return
|
|
}
|
|
|
|
func (pds *PacketData) IsValid() bool {
|
|
return pds.ok
|
|
}
|
|
|
|
func (pds *PacketData) Skip(skip int) {
|
|
if pds.Left() >= skip {
|
|
pds.offset += skip
|
|
} else {
|
|
pds.ok = false
|
|
}
|
|
}
|
|
|
|
// Returns number of bytes remaining in
|
|
// the buffer.
|
|
func (pds *PacketData) Left() int {
|
|
return int(pds.maxsize - pds.offset)
|
|
}
|
|
|
|
// Returns the size of the currently-assembled data
|
|
// stream
|
|
func (pds *PacketData) Size() int {
|
|
return pds.offset
|
|
}
|
|
|
|
// Get the next byte from the PacketData as a uint64
|
|
func (pds *PacketData) next() (ret uint64) {
|
|
if pds.offset < pds.maxsize {
|
|
ret = uint64(pds.Buf[pds.offset])
|
|
pds.offset += 1
|
|
return
|
|
} else {
|
|
pds.ok = false
|
|
}
|
|
return 0
|
|
}
|
|
|
|
// Get the next byte from the PacketData as a byte (uint8)
|
|
func (pds *PacketData) Next8() (ret uint8) {
|
|
if pds.offset < pds.maxsize {
|
|
ret = uint8(pds.Buf[pds.offset])
|
|
pds.offset += 1
|
|
return
|
|
} else {
|
|
pds.ok = false
|
|
}
|
|
return 0
|
|
}
|
|
|
|
// Put a byte (represented in an uint64) into the
|
|
// PacketData.
|
|
func (pds *PacketData) append(val uint64) {
|
|
if val > 0xff {
|
|
pds.ok = false
|
|
return
|
|
}
|
|
|
|
if pds.offset < pds.maxsize {
|
|
pds.Buf[pds.offset] = byte(val)
|
|
pds.offset += 1
|
|
} else {
|
|
pds.ok = false
|
|
pds.overshoot++
|
|
}
|
|
|
|
}
|
|
|
|
// Add a variably-sized integer to the PacketData.
|
|
// The PacketData will figure out the most efficient
|
|
// encoding based on the binary representation of the value.
|
|
func (pds *PacketData) addVarint(val uint64) {
|
|
i := val
|
|
|
|
if (i&0x8000000000000000) != 0 && ^i < 0x100000000 {
|
|
// Signed number
|
|
i = ^i
|
|
if i <= 0x3 {
|
|
// Short for -1 to -4
|
|
pds.append(0xfc | i)
|
|
} else {
|
|
pds.append(0xf8)
|
|
}
|
|
}
|
|
if i < 0x80 {
|
|
// Needs top bit clear
|
|
pds.append(i)
|
|
} else if i < 0x4000 {
|
|
// Needs two top bits clear
|
|
pds.append((i >> 8) | 0x80)
|
|
pds.append(i & 0xff)
|
|
} else if i < 0x10000000 {
|
|
// Needs three top bits clear
|
|
pds.append((i >> 16) | 0xc0)
|
|
pds.append((i >> 8) & 0xff)
|
|
pds.append(i & 0xff)
|
|
} else if i < 0x100000000 {
|
|
// Full 32 bit integer
|
|
pds.append(0xf0)
|
|
pds.append((i >> 24) & 0xff)
|
|
pds.append((i >> 16) & 0xff)
|
|
pds.append((i >> 8) & 0xff)
|
|
pds.append(i & 0xff)
|
|
} else {
|
|
// 64 bit val
|
|
pds.append(0xf4)
|
|
pds.append((i >> 56) & 0xff)
|
|
pds.append((i >> 48) & 0xff)
|
|
pds.append((i >> 40) & 0xff)
|
|
pds.append((i >> 32) & 0xff)
|
|
pds.append((i >> 24) & 0xff)
|
|
pds.append((i >> 16) & 0xff)
|
|
pds.append((i >> 8) & 0xff)
|
|
pds.append(i & 0xff)
|
|
}
|
|
}
|
|
|
|
func (pds *PacketData) getVarint() (i uint64) {
|
|
v := pds.next()
|
|
|
|
if (v & 0x80) == 0x00 {
|
|
i = (v & 0x7f)
|
|
} else if (v & 0xc0) == 0x80 {
|
|
i = (v&0x3f)<<8 | pds.next()
|
|
} else if (v & 0xf0) == 0xf0 {
|
|
switch v & 0xfc {
|
|
case 0xf0:
|
|
i = pds.next()<<24 | pds.next()<<16 | pds.next()<<8 | pds.next()
|
|
case 0xf4:
|
|
i = pds.next()<<56 | pds.next()<<48 | pds.next()<<40 | pds.next()<<32 | pds.next()<<24 | pds.next()<<16 | pds.next()<<8 | pds.next()
|
|
case 0xf8:
|
|
i = ^pds.getVarint()
|
|
case 0xfc:
|
|
i = ^(v & 0x03)
|
|
default:
|
|
pds.ok = false
|
|
i = 0
|
|
}
|
|
} else if (v & 0xf0) == 0xe0 {
|
|
i = (v&0x0f)<<24 | pds.next()<<16 | pds.next()<<8 | pds.next()
|
|
} else if (v & 0xe0) == 0xc0 {
|
|
i = (v&0x1f)<<16 | pds.next()<<8 | pds.next()
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
// Read a uint64 from the PacketData
|
|
func (pds *PacketData) GetUint64() uint64 {
|
|
return pds.getVarint()
|
|
}
|
|
|
|
// Write a uint64 to the PacketData
|
|
func (pds *PacketData) PutUint64(val uint64) {
|
|
pds.addVarint(val)
|
|
}
|
|
|
|
// Read a uint32 from the PacketData
|
|
func (pds *PacketData) GetUint32() uint32 {
|
|
return uint32(pds.getVarint())
|
|
}
|
|
|
|
// Write a uint32 to the PacketData
|
|
func (pds *PacketData) PutUint32(val uint32) {
|
|
pds.addVarint(uint64(val))
|
|
}
|
|
|
|
// Read a uint16 from the PacketData
|
|
func (pds *PacketData) GetUint16() uint16 {
|
|
return uint16(pds.getVarint())
|
|
}
|
|
|
|
// Write a uint16 to the PacketData
|
|
func (pds *PacketData) PutUint16(val uint16) {
|
|
pds.addVarint(uint64(val))
|
|
}
|
|
|
|
// Read a uint8 from the PacketData
|
|
func (pds *PacketData) GetUint8() uint8 {
|
|
varint := pds.getVarint()
|
|
return uint8(varint)
|
|
}
|
|
|
|
// Write a uint8 to the PacketData
|
|
func (pds *PacketData) PutUint8(val uint8) {
|
|
pds.addVarint(uint64(val))
|
|
}
|
|
|
|
// Read a int64 from the PacketData
|
|
func (pds *PacketData) GetInt64() int64 {
|
|
return int64(pds.getVarint())
|
|
}
|
|
|
|
// Write a int64 to the PacketData
|
|
func (pds *PacketData) PutInt64(val int64) {
|
|
pds.addVarint(uint64(val))
|
|
}
|
|
|
|
// Read a int32 from the PacketData
|
|
func (pds *PacketData) GetInt32() int32 {
|
|
return int32(pds.getVarint())
|
|
}
|
|
|
|
// Write a int32 to the PacketData
|
|
func (pds *PacketData) PutInt32(val int32) {
|
|
pds.addVarint(uint64(val))
|
|
}
|
|
|
|
// Read a int16 from the PacketData
|
|
func (pds *PacketData) GetInt16() int16 {
|
|
return int16(pds.getVarint())
|
|
}
|
|
|
|
// Write a int16 to the PacketData
|
|
func (pds *PacketData) PutInt16(val int16) {
|
|
pds.addVarint(uint64(val))
|
|
}
|
|
|
|
// Read a int8 from the PacketData
|
|
func (pds *PacketData) GetInt8() int8 {
|
|
return int8(pds.getVarint())
|
|
}
|
|
|
|
// Write a int8 to the PacketData
|
|
func (pds *PacketData) PutInt8(val int8) {
|
|
pds.addVarint(uint64(val))
|
|
}
|
|
|
|
// Read a float32 from the PacketData
|
|
func (pds *PacketData) GetFloat32() float32 {
|
|
if pds.Left() < 4 {
|
|
pds.ok = false
|
|
return 0
|
|
}
|
|
|
|
var val uint32
|
|
|
|
val = uint32(pds.Next8())<<24 | uint32(pds.Next8())<<16 | uint32(pds.Next8())<<8 | uint32(pds.Next8())
|
|
return math.Float32frombits(val)
|
|
}
|
|
|
|
// Write a float32 to the PacketData
|
|
func (pds *PacketData) PutFloat32(val float32) {
|
|
bits := math.Float32bits(val)
|
|
pds.append(uint64((bits >> 24) & 0xff))
|
|
pds.append(uint64((bits >> 16) & 0xff))
|
|
pds.append(uint64((bits >> 8) & 0xff))
|
|
pds.append(uint64(bits & 0xff))
|
|
}
|
|
|
|
// Read a float64 from the PacketData.
|
|
func (pds *PacketData) GetFloat64() float64 {
|
|
if pds.Left() < 8 {
|
|
pds.ok = false
|
|
return 0
|
|
}
|
|
|
|
var val uint64
|
|
val = uint64(pds.Next8())<<56 | uint64(pds.Next8())<<48 | uint64(pds.Next8())<<40 | uint64(pds.Next8())<<32 | uint64(pds.Next8())<<24 | uint64(pds.Next8())<<16 | uint64(pds.Next8())<<8 | uint64(pds.Next8())
|
|
|
|
return math.Float64frombits(val)
|
|
}
|
|
|
|
// Write a float64 to the PacketData
|
|
func (pds *PacketData) PutFloat64(val float64) {
|
|
bits := math.Float64bits(val)
|
|
pds.append((bits >> 56) & 0xff)
|
|
pds.append((bits >> 48) & 0xff)
|
|
pds.append((bits >> 40) & 0xff)
|
|
pds.append((bits >> 32) & 0xff)
|
|
pds.append((bits >> 24) & 0xff)
|
|
pds.append((bits >> 16) & 0xff)
|
|
pds.append((bits >> 8) & 0xff)
|
|
pds.append(bits & 0xff)
|
|
}
|
|
|
|
// Copy a buffer out of the PacketData into dst.
|
|
func (pds *PacketData) CopyBytes(dst []byte) {
|
|
if pds.Left() >= len(dst) {
|
|
if copy(dst, pds.Buf[pds.offset:pds.offset+len(dst)]) != len(dst) {
|
|
pds.ok = false
|
|
}
|
|
} else {
|
|
pds.ok = false
|
|
}
|
|
}
|
|
|
|
// Put a buffer src into the PacketData at the
|
|
// current offset.
|
|
func (pds *PacketData) PutBytes(src []byte) {
|
|
if pds.Left() >= len(src) {
|
|
if copy(pds.Buf[pds.offset:pds.offset+len(src)], src) != len(src) {
|
|
pds.ok = false
|
|
} else {
|
|
pds.offset += len(src)
|
|
}
|
|
} else {
|
|
pds.overshoot += len(src) - pds.Left()
|
|
pds.ok = false
|
|
}
|
|
}
|