uint32.go

Documentation: github.com/gogo/protobuf/io

     1  // Protocol Buffers for Go with Gadgets
     2  //
     3  // Copyright (c) 2013, The GoGo Authors. All rights reserved.
     4  // http://github.com/gogo/protobuf
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    11  // notice, this list of conditions and the following disclaimer.
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    13  // copyright notice, this list of conditions and the following disclaimer
    14  // in the documentation and/or other materials provided with the
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    17  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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    20  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
    21  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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    24  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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    26  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
    27  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    28  
    29  package io
    30  
    31  import (
    32  	"encoding/binary"
    33  	"io"
    34  
    35  	"github.com/gogo/protobuf/proto"
    36  )
    37  
    38  const uint32BinaryLen = 4
    39  
    40  func NewUint32DelimitedWriter(w io.Writer, byteOrder binary.ByteOrder) WriteCloser {
    41  	return &uint32Writer{w, byteOrder, nil, make([]byte, uint32BinaryLen)}
    42  }
    43  
    44  func NewSizeUint32DelimitedWriter(w io.Writer, byteOrder binary.ByteOrder, size int) WriteCloser {
    45  	return &uint32Writer{w, byteOrder, make([]byte, size), make([]byte, uint32BinaryLen)}
    46  }
    47  
    48  type uint32Writer struct {
    49  	w         io.Writer
    50  	byteOrder binary.ByteOrder
    51  	buffer    []byte
    52  	lenBuf    []byte
    53  }
    54  
    55  func (this *uint32Writer) writeFallback(msg proto.Message) error {
    56  	data, err := proto.Marshal(msg)
    57  	if err != nil {
    58  		return err
    59  	}
    60  
    61  	length := uint32(len(data))
    62  	this.byteOrder.PutUint32(this.lenBuf, length)
    63  	if _, err = this.w.Write(this.lenBuf); err != nil {
    64  		return err
    65  	}
    66  	_, err = this.w.Write(data)
    67  	return err
    68  }
    69  
    70  func (this *uint32Writer) WriteMsg(msg proto.Message) error {
    71  	m, ok := msg.(marshaler)
    72  	if !ok {
    73  		return this.writeFallback(msg)
    74  	}
    75  
    76  	n, ok := getSize(m)
    77  	if !ok {
    78  		return this.writeFallback(msg)
    79  	}
    80  
    81  	size := n + uint32BinaryLen
    82  	if size > len(this.buffer) {
    83  		this.buffer = make([]byte, size)
    84  	}
    85  
    86  	this.byteOrder.PutUint32(this.buffer, uint32(n))
    87  	if _, err := m.MarshalTo(this.buffer[uint32BinaryLen:]); err != nil {
    88  		return err
    89  	}
    90  
    91  	_, err := this.w.Write(this.buffer[:size])
    92  	return err
    93  }
    94  
    95  func (this *uint32Writer) Close() error {
    96  	if closer, ok := this.w.(io.Closer); ok {
    97  		return closer.Close()
    98  	}
    99  	return nil
   100  }
   101  
   102  type uint32Reader struct {
   103  	r         io.Reader
   104  	byteOrder binary.ByteOrder
   105  	lenBuf    []byte
   106  	buf       []byte
   107  	maxSize   int
   108  }
   109  
   110  func NewUint32DelimitedReader(r io.Reader, byteOrder binary.ByteOrder, maxSize int) ReadCloser {
   111  	return &uint32Reader{r, byteOrder, make([]byte, 4), nil, maxSize}
   112  }
   113  
   114  func (this *uint32Reader) ReadMsg(msg proto.Message) error {
   115  	if _, err := io.ReadFull(this.r, this.lenBuf); err != nil {
   116  		return err
   117  	}
   118  	length32 := this.byteOrder.Uint32(this.lenBuf)
   119  	length := int(length32)
   120  	if length < 0 || length > this.maxSize {
   121  		return io.ErrShortBuffer
   122  	}
   123  	if length > len(this.buf) {
   124  		this.buf = make([]byte, length)
   125  	}
   126  	_, err := io.ReadFull(this.r, this.buf[:length])
   127  	if err != nil {
   128  		return err
   129  	}
   130  	return proto.Unmarshal(this.buf[:length], msg)
   131  }
   132  
   133  func (this *uint32Reader) Close() error {
   134  	if closer, ok := this.r.(io.Closer); ok {
   135  		return closer.Close()
   136  	}
   137  	return nil
   138  }
   139
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