github.com/janelia-flyem/dvid@v1.0.0/datatype/multichan16/v3draw.go (about)

     1  // Implements reading and writing of V3D Raw File formats.
     2  
     3  package multichan16
     4  
     5  import (
     6  	"encoding/binary"
     7  	"fmt"
     8  	"io"
     9  
    10  	"github.com/janelia-flyem/dvid/datatype/imageblk"
    11  	"github.com/janelia-flyem/dvid/dvid"
    12  )
    13  
    14  type V3DRawMarshaler struct{}
    15  
    16  func (V3DRawMarshaler) UnmarshalV3DRaw(reader io.Reader) ([]*Channel, error) {
    17  	magicString := make([]byte, 24)
    18  	if n, err := reader.Read(magicString); n != 24 || err != nil {
    19  		return nil, fmt.Errorf("error reading magic string in V3D Raw file: %v", err)
    20  	}
    21  	if string(magicString) != "raw_image_stack_by_hpeng" {
    22  		return nil, fmt.Errorf("bad magic string in V3D Raw File: %s", string(magicString))
    23  	}
    24  	endianType := make([]byte, 1, 1)
    25  	if n, err := reader.Read(endianType); n != 1 || err != nil {
    26  		return nil, fmt.Errorf("could not read endianness of V3D Raw file: %v", err)
    27  	}
    28  	var byteOrder binary.ByteOrder
    29  	switch string(endianType) {
    30  	case "L":
    31  		byteOrder = binary.LittleEndian
    32  	case "B":
    33  		return nil, fmt.Errorf("cannot handle big endian byte order in V3D Raw File")
    34  	default:
    35  		return nil, fmt.Errorf("illegal byte order '%s' in V3D Raw File", endianType)
    36  	}
    37  	var dataType uint16
    38  	if err := binary.Read(reader, byteOrder, &dataType); err != nil {
    39  		return nil, err
    40  	}
    41  	var bytesPerVoxel int32
    42  	switch dataType {
    43  	case 1:
    44  		bytesPerVoxel = 1
    45  	case 2:
    46  		bytesPerVoxel = 2
    47  	default:
    48  		return nil, fmt.Errorf("cannot handle V3D Raw File with data type %d", dataType)
    49  	}
    50  	var width, height, depth, numChannels uint32
    51  	if err := binary.Read(reader, byteOrder, &width); err != nil {
    52  		return nil, fmt.Errorf("error reading width in V3D Raw File: %v", err)
    53  	}
    54  	if err := binary.Read(reader, byteOrder, &height); err != nil {
    55  		return nil, fmt.Errorf("error reading height in V3D Raw File: %v", err)
    56  	}
    57  	if err := binary.Read(reader, byteOrder, &depth); err != nil {
    58  		return nil, fmt.Errorf("error reading depth in V3D Raw File: %v", err)
    59  	}
    60  	if err := binary.Read(reader, byteOrder, &numChannels); err != nil {
    61  		return nil, fmt.Errorf("error reading # channels in V3D Raw File: %v", err)
    62  	}
    63  
    64  	// Allocate the V3DRaw struct for the # channels
    65  	totalBytes := int(bytesPerVoxel) * int(width*height*depth)
    66  	size := dvid.Point3d{int32(width), int32(height), int32(depth)}
    67  	volume := dvid.NewSubvolume(dvid.Point3d{0, 0, 0}, size)
    68  	v3draw := make([]*Channel, numChannels, numChannels)
    69  	var c int32
    70  	for c = 0; c < int32(numChannels); c++ {
    71  		data := make([]uint8, totalBytes, totalBytes)
    72  		var t dvid.DataType
    73  		switch bytesPerVoxel {
    74  		case 1:
    75  			t = dvid.T_uint8
    76  		case 2:
    77  			t = dvid.T_uint16
    78  		}
    79  		values := dvid.DataValues{
    80  			{
    81  				T:     t,
    82  				Label: fmt.Sprintf("channel%d", c),
    83  			},
    84  		}
    85  		v := imageblk.NewVoxels(volume, values, data, int32(width)*bytesPerVoxel)
    86  		v3draw[c] = &Channel{
    87  			Voxels:     v,
    88  			channelNum: c + 1,
    89  		}
    90  	}
    91  
    92  	// Read in the data for each channel
    93  	for c = 0; c < int32(numChannels); c++ {
    94  		if err := binary.Read(reader, byteOrder, v3draw[c].Data()); err != nil {
    95  			return nil, fmt.Errorf("error reading data for channel %d: %v", c, err)
    96  		}
    97  	}
    98  	return v3draw, nil
    99  }