public override ChunkRaw CreateRawChunk()
{
if (Key.Length == 0)
{
throw new PngjException("Text chunk key must be non empty");
}
using var ba = new MemoryStream();
ChunkHelper.WriteBytesToStream(ba, ChunkHelper.ToBytes(Key));
ba.WriteByte(0); // separator
ba.WriteByte(compressed ? (byte)1 : (byte)0);
ba.WriteByte(0); // compression method (always 0)
ChunkHelper.WriteBytesToStream(ba, ChunkHelper.ToBytes(langTag));
ba.WriteByte(0); // separator
ChunkHelper.WriteBytesToStream(ba, ChunkHelper.ToBytesUTF8(translatedTag));
ba.WriteByte(0); // separator
var textbytes = ChunkHelper.ToBytesUTF8(Val);
if (compressed)
{
textbytes = ChunkHelper.CompressBytes(textbytes, true);
}
ChunkHelper.WriteBytesToStream(ba, textbytes);
var b = ba.ToArray();
var chunk = CreateEmptyChunk(b.Length, false);
chunk.Data = b;
return(chunk);
}
public override void ParseFromRaw(ChunkRaw c)
{
if (c is null)
{
throw new System.ArgumentNullException(nameof(c));
}
var nullsFound = 0;
var nullsIdx = new int[3];
for (var k = 0; k < c.Data.Length; k++)
{
if (c.Data[k] != 0)
{
continue;
}
nullsIdx[nullsFound] = k;
nullsFound++;
if (nullsFound == 1)
{
k += 2;
}
if (nullsFound == 3)
{
break;
}
}
if (nullsFound != 3)
{
throw new PngjException("Bad formed PngChunkITXT chunk");
}
Key = ChunkHelper.ToString(c.Data, 0, nullsIdx[0]);
var i = nullsIdx[0] + 1;
compressed = c.Data[i] != 0;
i++;
if (compressed && c.Data[i] != 0)
{
throw new PngjException("Bad formed PngChunkITXT chunk - bad compression method ");
}
langTag = ChunkHelper.ToString(c.Data, i, nullsIdx[1] - i);
translatedTag = ChunkHelper.ToStringUTF8(c.Data, nullsIdx[1] + 1, nullsIdx[2] - nullsIdx[1] - 1);
i = nullsIdx[2] + 1;
if (compressed)
{
var bytes = ChunkHelper.CompressBytes(c.Data, i, c.Data.Length - i, false);
Val = ChunkHelper.ToStringUTF8(bytes);
}
else
{
Val = ChunkHelper.ToStringUTF8(c.Data, i, c.Data.Length - i);
}
}
/// <summary>
/// Sets profile name and profile
/// </summary>
/// <param name="name">profile name </param>
/// <param name="profile">profile (uncompressed)</param>
public void SetProfileNameAndContent(string name, byte[] profile)
{
if (profile is null)
{
throw new ArgumentNullException(nameof(profile));
}
profileName = name;
compressedProfile = ChunkHelper.CompressBytes(profile, true);
}
public override ChunkRaw CreateRawChunk()
{
if (Key.Length == 0)
{
throw new PngjException("Text chunk key must be non empty");
}
using var ba = new MemoryStream();
ChunkHelper.WriteBytesToStream(ba, ChunkHelper.ToBytes(Key));
ba.WriteByte(0); // separator
ba.WriteByte(0); // compression method: 0
var textbytes = ChunkHelper.CompressBytes(ChunkHelper.ToBytes(Val), true);
ChunkHelper.WriteBytesToStream(ba, textbytes);
var b = ba.ToArray();
var chunk = CreateEmptyChunk(b.Length, false);
chunk.Data = b;
return(chunk);
}
public override void ParseFromRaw(ChunkRaw c)
{
if (c is null)
{
throw new ArgumentNullException(nameof(c));
}
var nullsep = -1;
for (var i = 0; i < c.Data.Length; i++)
{ // look for first zero
if (c.Data[i] != 0)
{
continue;
}
nullsep = i;
break;
}
if (nullsep < 0 || nullsep > c.Data.Length - 2)
{
throw new PngjException("bad zTXt chunk: no separator found");
}
Key = ChunkHelper.ToString(c.Data, 0, nullsep);
var compmet = (int)c.Data[nullsep + 1];
if (compmet != 0)
{
throw new PngjException("bad zTXt chunk: unknown compression method");
}
var uncomp = ChunkHelper.CompressBytes(c.Data, nullsep + 2, c.Data.Length - nullsep - 2, false); // uncompress
Val = ChunkHelper.ToString(uncomp);
}
/// <summary>
/// This uncompresses the string!
/// </summary>
/// <returns></returns>
public byte[] GetProfile()
{
return(ChunkHelper.CompressBytes(compressedProfile, false));
}