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mirror of https://github.com/OpenDiablo2/OpenDiablo2 synced 2024-11-15 16:56:00 -05:00
OpenDiablo2/d2common/d2datautils/stream_writer.go

139 lines
3.0 KiB
Go

package d2datautils
import (
"bytes"
"log"
)
// StreamWriter allows you to create a byte array by streaming in writes of various sizes
type StreamWriter struct {
data *bytes.Buffer
bitOffset int
bitCache byte
}
// CreateStreamWriter creates a new StreamWriter instance
func CreateStreamWriter() *StreamWriter {
result := &StreamWriter{
data: new(bytes.Buffer),
}
return result
}
// GetBytes returns the the byte slice of the underlying data
func (v *StreamWriter) GetBytes() []byte {
return v.data.Bytes()
}
// PushBytes writes a bytes to the stream
func (v *StreamWriter) PushBytes(b ...byte) {
for _, i := range b {
v.data.WriteByte(i)
}
}
// PushBit pushes single bit into stream
// WARNING: if you'll use PushBit, offset'll be less than 8, and if you'll
// use another Push... method, bits'll not be pushed
func (v *StreamWriter) PushBit(b bool) {
if b {
v.bitCache |= 1 << v.bitOffset
}
v.bitOffset++
if v.bitOffset != bitsPerByte {
return
}
v.PushBytes(v.bitCache)
v.bitCache = 0
v.bitOffset = 0
}
// PushBits pushes bits (with max range 8)
func (v *StreamWriter) PushBits(b byte, bits int) {
if bits > bitsPerByte {
log.Print("input bits number must be less (or equal) than 8")
}
val := b
for i := 0; i < bits; i++ {
v.PushBit(val&1 == 1)
val >>= 1
}
}
// PushBits16 pushes bits (with max range 16)
func (v *StreamWriter) PushBits16(b uint16, bits int) {
if bits > bitsPerByte*bytesPerint16 {
log.Print("input bits number must be less (or equal) than 16")
}
val := b
for i := 0; i < bits; i++ {
v.PushBit(val&1 == 1)
val >>= 1
}
}
// PushBits32 pushes bits (with max range 32)
func (v *StreamWriter) PushBits32(b uint32, bits int) {
if bits > bitsPerByte*bytesPerint32 {
log.Print("input bits number must be less (or equal) than 32")
}
val := b
for i := 0; i < bits; i++ {
v.PushBit(val&1 == 1)
val >>= 1
}
}
// PushInt16 writes a int16 word to the stream
func (v *StreamWriter) PushInt16(val int16) {
v.PushUint16(uint16(val))
}
// PushUint16 writes an uint16 word to the stream
//nolint
func (v *StreamWriter) PushUint16(val uint16) {
v.data.WriteByte(byte(val))
v.data.WriteByte(byte(val >> 8))
}
// PushInt32 writes a int32 dword to the stream
func (v *StreamWriter) PushInt32(val int32) {
v.PushUint32(uint32(val))
}
// PushUint32 writes a uint32 dword to the stream
//nolint
func (v *StreamWriter) PushUint32(val uint32) {
v.data.WriteByte(byte(val))
v.data.WriteByte(byte(val >> 8))
v.data.WriteByte(byte(val >> 16))
v.data.WriteByte(byte(val >> 24))
}
// PushInt64 writes a uint64 qword to the stream
func (v *StreamWriter) PushInt64(val int64) {
v.PushUint64(uint64(val))
}
// PushUint64 writes a uint64 qword to the stream
//nolint
func (v *StreamWriter) PushUint64(val uint64) {
v.data.WriteByte(byte(val))
v.data.WriteByte(byte(val >> 8))
v.data.WriteByte(byte(val >> 16))
v.data.WriteByte(byte(val >> 24))
v.data.WriteByte(byte(val >> 32))
v.data.WriteByte(byte(val >> 40))
v.data.WriteByte(byte(val >> 48))
v.data.WriteByte(byte(val >> 56))
}