internal static byte[] CompressBytes(byte[] ori, int offset, int len, bool compress)
{
try
{
MemoryStream inb = new MemoryStream(ori, offset, len);
Stream inx = inb;
if (!compress)
{
inx = ZlibStreamFactory.CreateZlibInputStream(inb);
}
MemoryStream outb = new MemoryStream();
Stream outx = outb;
if (compress)
{
outx = ZlibStreamFactory.CreateZlibOutputStream(outb);
}
ShovelInToOut(inx, outx);
inx.Close();
outx.Close();
byte[] res = outb.ToArray();
return(res);
}
catch (Exception e)
{
throw new PngjException(e);
}
}
/// <summary>
/// Reads chunks before first IDAT. Position before: after IDHR (crc included)
/// Position after: just after the first IDAT chunk id Returns length of first
/// IDAT chunk , -1 if not found
/// </summary>
///
private void ReadFirstChunks()
{
if (!FirstChunksNotYetRead())
{
return;
}
int clen = 0;
bool found = false;
byte[] chunkid = new byte[4]; // it's important to reallocate in each
this.CurrentChunkGroup = ChunksList.CHUNK_GROUP_1_AFTERIDHR;
while (!found)
{
clen = PngHelperInternal.ReadInt4(inputStream);
offset += 4;
if (clen < 0)
{
break;
}
PngHelperInternal.ReadBytes(inputStream, chunkid, 0, 4);
offset += 4;
if (PngCsUtils.arraysEqual4(chunkid, Hjg.Pngcs.Chunks.ChunkHelper.b_IDAT))
{
found = true;
this.CurrentChunkGroup = ChunksList.CHUNK_GROUP_4_IDAT;
// add dummy idat chunk to list
chunksList.AppendReadChunk(new PngChunkIDAT(ImgInfo, clen, offset - 8), CurrentChunkGroup);
break;
}
else if (PngCsUtils.arraysEqual4(chunkid, Hjg.Pngcs.Chunks.ChunkHelper.b_IEND))
{
throw new PngjInputException("END chunk found before image data (IDAT) at offset=" + offset);
}
String chunkids = ChunkHelper.ToString(chunkid);
if (chunkids.Equals(ChunkHelper.PLTE))
{
this.CurrentChunkGroup = ChunksList.CHUNK_GROUP_2_PLTE;
}
ReadChunk(chunkid, clen, false);
if (chunkids.Equals(ChunkHelper.PLTE))
{
this.CurrentChunkGroup = ChunksList.CHUNK_GROUP_3_AFTERPLTE;
}
}
int idatLen = found ? clen : -1;
if (idatLen < 0)
{
throw new PngjInputException("first idat chunk not found!");
}
iIdatCstream = new PngIDatChunkInputStream(inputStream, idatLen, offset);
idatIstream = ZlibStreamFactory.CreateZlibInputStream(iIdatCstream, true);
if (!crcEnabled)
{
iIdatCstream.DisableCrcCheck();
}
}
