using System;

using System.Linq;

using System.Runtime.InteropServices;

using System.Text;

using static Tensorflow.Binding;

namespace Tensorflow

{

public partial class Tensor

{

const int TF_TSRING_SIZE = 24;

public IntPtr StringTensor(string[] strings, TensorShape shape)

{

// convert string array to byte[][]

var buffer = new byte[strings.Length][];

for (var i = 0; i < strings.Length; i++)

buffer[i] = Encoding.UTF8.GetBytes(strings[i]);

return StringTensor(buffer, shape);

}

public IntPtr StringTensor(byte[][] buffer, TensorShape shape)

{

var handle = c_api.TF_AllocateTensor(TF_DataType.TF_STRING,

shape.ndim == 0 ? null : shape.dims.Select(x => (long)x).ToArray(),

shape.ndim,

(ulong)shape.size * TF_TSRING_SIZE);

var tstr = c_api.TF_TensorData(handle);

#if TRACK_TENSOR_LIFE

print($"New TString 0x{handle.ToString("x16")} {AllocationType} Data: 0x{tstr.ToString("x16")}");

#endif

for (int i = 0; i < buffer.Length; i++)

{

c_api.TF_StringInit(tstr);

c_api.TF_StringCopy(tstr, buffer[i], buffer[i].Length);

var data = c_api.TF_StringGetDataPointer(tstr);

tstr += TF_TSRING_SIZE;

}

return handle;

}

public string[] StringData()

{

var buffer = StringBytes();

var _str = new string[buffer.Length];

for (int i = 0; i < _str.Length; i++)

_str[i] = Encoding.UTF8.GetString(buffer[i]);

return _str;

}

public byte[][] StringBytes()

{

if (dtype != TF_DataType.TF_STRING)

throw new InvalidOperationException($"Unable to call StringData when dtype != TF_DataType.TF_STRING (dtype is {dtype})");

//

// TF_STRING tensors are encoded with a table of 8-byte offsets followed by TF_StringEncode-encoded bytes.

// [offset1, offset2,...,offsetn, s1size, s1bytes, s2size, s2bytes,...,snsize,snbytes]

//

int size = 1;

foreach (var s in TensorShape.dims)

size *= s;

var buffer = new byte[size][];

var tstrings = TensorDataPointer;

for (int i = 0; i < buffer.Length; i++)

{

var data = c_api.TF_StringGetDataPointer(tstrings);

var len = c_api.TF_StringGetSize(tstrings);

buffer[i] = new byte[len];

// var capacity = c_api.TF_StringGetCapacity(tstrings);

// var type = c_api.TF_StringGetType(tstrings);

Marshal.Copy(data, buffer[i], 0, Convert.ToInt32(len));

tstrings += TF_TSRING_SIZE;

}

return buffer;

}

}

}