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