using System;
using System.IO;
using Hjg.Pngcs.Zlib;

namespace Hjg.Pngcs.Chunks
{
	// Token: 0x02000005 RID: 5
	public class ChunkRaw
	{
		// Token: 0x06000025 RID: 37 RVA: 0x000025C0 File Offset: 0x000007C0
		internal ChunkRaw(int length, byte[] idbytes, bool alloc)
		{
			this.IdBytes = new byte[4];
			this.Data = null;
			this.crcval = 0;
			this.Length = length;
			Array.Copy(idbytes, 0, this.IdBytes, 0, 4);
			if (alloc)
			{
				this.AllocData();
			}
		}

		// Token: 0x06000026 RID: 38 RVA: 0x0000260C File Offset: 0x0000080C
		private int ComputeCrc()
		{
			CRC32 crc = PngHelperInternal.GetCRC();
			crc.Reset();
			crc.Update(this.IdBytes, 0, 4);
			if (this.Length > 0)
			{
				crc.Update(this.Data, 0, this.Length);
			}
			return (int)crc.GetValue();
		}

		// Token: 0x06000027 RID: 39 RVA: 0x00002658 File Offset: 0x00000858
		internal void WriteChunk(Stream os)
		{
			if (this.IdBytes.Length != 4)
			{
				throw new PngjOutputException("bad chunkid [" + ChunkHelper.ToString(this.IdBytes) + "]");
			}
			this.crcval = this.ComputeCrc();
			PngHelperInternal.WriteInt4(os, this.Length);
			PngHelperInternal.WriteBytes(os, this.IdBytes);
			if (this.Length > 0)
			{
				PngHelperInternal.WriteBytes(os, this.Data, 0, this.Length);
			}
			PngHelperInternal.WriteInt4(os, this.crcval);
		}

		// Token: 0x06000028 RID: 40 RVA: 0x000026DC File Offset: 0x000008DC
		internal int ReadChunkData(Stream stream, bool checkCrc)
		{
			PngHelperInternal.ReadBytes(stream, this.Data, 0, this.Length);
			this.crcval = PngHelperInternal.ReadInt4(stream);
			if (checkCrc)
			{
				int num = this.ComputeCrc();
				if (num != this.crcval)
				{
					throw new PngjBadCrcException(string.Concat(new object[]
					{
						"crc invalid for chunk ",
						this.ToString(),
						" calc=",
						num,
						" read=",
						this.crcval
					}));
				}
			}
			return this.Length + 4;
		}

		// Token: 0x06000029 RID: 41 RVA: 0x0000276E File Offset: 0x0000096E
		internal MemoryStream GetAsByteStream()
		{
			return new MemoryStream(this.Data);
		}

		// Token: 0x0600002A RID: 42 RVA: 0x0000277B File Offset: 0x0000097B
		private void AllocData()
		{
			if (this.Data == null || this.Data.Length < this.Length)
			{
				this.Data = new byte[this.Length];
			}
		}

		// Token: 0x0600002B RID: 43 RVA: 0x000027A8 File Offset: 0x000009A8
		public override string ToString()
		{
			return string.Concat(new object[]
			{
				"chunkid=",
				ChunkHelper.ToString(this.IdBytes),
				" len=",
				this.Length
			});
		}

		// Token: 0x04000025 RID: 37
		public readonly int Length;

		// Token: 0x04000026 RID: 38
		public readonly byte[] IdBytes;

		// Token: 0x04000027 RID: 39
		public byte[] Data;

		// Token: 0x04000028 RID: 40
		private int crcval;
	}
}