tif_swab.cs

// tif_swab.cs
//
// Based on LIBTIFF, Version 3.9.4 - 15-Jun-2010
// Copyright (c) 2006-2010 by the Authors
// Copyright (c) 1988-1997 Sam Leffler
// Copyright (c) 1991-1997 Silicon Graphics, Inc.
//
// Permission to use, copy, modify, distribute, and sell this software and
// its documentation for any purpose is hereby granted without fee, provided
// that (i) the above copyright notices and this permission notice appear in
// all copies of the software and related documentation, and (ii) the names of
// Sam Leffler and Silicon Graphics may not be used in any advertising or
// publicity relating to the software without the specific, prior written
// permission of Sam Leffler and Silicon Graphics.
//
// THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
// EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
// WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
//
// IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
// ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
// OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
// WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
// LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
// OF THIS SOFTWARE.

// TIFF Library Bit & Byte Swapping Support.
// XXX We assume short=16-bits and int=32-bits XXX

using System;
using System.Collections.Generic;

namespace Free.Ports.LibTiff
{
	public static partial class libtiff
	{
		public unsafe static void TIFFSwab(ref short wp)
		{
			fixed(short* cp_=&wp)
			{
				byte* cp=(byte*)cp_;
				byte t=cp[1]; cp[1]=cp[0]; cp[0]=t;
			}
		}

		public unsafe static void TIFFSwab(ref ushort wp)
		{
			fixed(ushort* cp_=&wp)
			{
				byte* cp=(byte*)cp_;
				byte t=cp[1]; cp[1]=cp[0]; cp[0]=t;
			}
		}

		public unsafe static void TIFFSwab(ref int lp)
		{
			fixed(int* cp_=&lp)
			{
				byte* cp=(byte*)cp_;
				byte t=cp[3]; cp[3]=cp[0]; cp[0]=t;
				t=cp[2]; cp[2]=cp[1]; cp[1]=t;
			}
		}

		public unsafe static void TIFFSwab(ref uint lp)
		{
			fixed(uint* cp_=&lp)
			{
				byte* cp=(byte*)cp_;
				byte t=cp[3]; cp[3]=cp[0]; cp[0]=t;
				t=cp[2]; cp[2]=cp[1]; cp[1]=t;
			}
		}

		public unsafe static void TIFFSwab(ref float lp)
		{
			fixed(float* cp_=&lp)
			{
				byte* cp=(byte*)cp_;
				byte t=cp[3]; cp[3]=cp[0]; cp[0]=t;
				t=cp[2]; cp[2]=cp[1]; cp[1]=t;
			}
		}

		public unsafe static void TIFFSwab(ref double dp)
		{
			fixed(double* cp_=&dp)
			{
				byte* cp=(byte*)cp_;
				byte t=cp[7]; cp[7]=cp[0]; cp[0]=t;
				t=cp[6]; cp[6]=cp[1]; cp[1]=t;
				t=cp[5]; cp[5]=cp[2]; cp[2]=t;
				t=cp[4]; cp[4]=cp[3]; cp[3]=t;
			}
		}

		public unsafe static void TIFFSwabArrayOfShort(byte[] cp0, uint n)
		{
			fixed(byte* cp_=cp0)
			{
				byte* cp=cp_;

				// XXX unroll loop some
				while((n--)>0)
				{
					byte t=cp[1]; cp[1]=cp[0]; cp[0]=t;
					cp+=2;
				}
			}
		}

		public unsafe static void TIFFSwabArrayOfShort(byte[] cp0, int cp0_offset, uint n)
		{
			fixed(byte* cp_=cp0)
			{
				byte* cp=cp_+cp0_offset;

				// XXX unroll loop some
				while((n--)>0)
				{
					byte t=cp[1]; cp[1]=cp[0]; cp[0]=t;
					cp+=2;
				}
			}
		}

		public unsafe static void TIFFSwabArrayOfTriples(byte[] cp0, uint n)
		{
			fixed(byte* cp_=cp0)
			{
				byte* cp=cp_;

				// XXX unroll loop some
				while((n--)>0)
				{
					byte t=cp[2]; cp[2]=cp[0]; cp[0]=t;
					cp+=3;
				}
			}
		}

		public unsafe static void TIFFSwabArrayOfTriples(byte[] cp0, int cp0_offset, uint n)
		{
			fixed(byte* cp_=cp0)
			{
				byte* cp=cp_+cp0_offset;

				// XXX unroll loop some
				while((n--)>0)
				{
					byte t=cp[2]; cp[2]=cp[0]; cp[0]=t;
					cp+=3;
				}
			}
		}

		public unsafe static void TIFFSwabArrayOfLong(byte[] cp0, uint n)
		{
			fixed(byte* cp_=cp0)
			{
				byte* cp=cp_;

				// XXX unroll loop some
				while((n--)>0)
				{
					byte t=cp[3]; cp[3]=cp[0]; cp[0]=t;
					t=cp[2]; cp[2]=cp[1]; cp[1]=t;
					cp+=4;
				}
			}
		}

		public unsafe static void TIFFSwabArrayOfLong(byte[] cp0, int cp0_offset, uint n)
		{
			fixed(byte* cp_=cp0)
			{
				byte* cp=cp_+cp0_offset;

				// XXX unroll loop some
				while((n--)>0)
				{
					byte t=cp[3]; cp[3]=cp[0]; cp[0]=t;
					t=cp[2]; cp[2]=cp[1]; cp[1]=t;
					cp+=4;
				}
			}
		}

		public unsafe static void TIFFSwabArrayOfDouble(byte[] cp0, uint n)
		{
			fixed(byte* cp_=cp0)
			{
				byte* cp=cp_;

				// XXX unroll loop some
				while((n--)>0)
				{
					byte t=cp[7]; cp[7]=cp[0]; cp[0]=t;
					t=cp[6]; cp[6]=cp[1]; cp[1]=t;
					t=cp[5]; cp[5]=cp[2]; cp[2]=t;
					t=cp[4]; cp[4]=cp[3]; cp[3]=t;
					cp+=4;
				}
			}
		}

		public unsafe static void TIFFSwabArrayOfDouble(byte[] cp0, int cp0_offset, uint n)
		{
			fixed(byte* cp_=cp0)
			{
				byte* cp=cp_+cp0_offset;

				// XXX unroll loop some
				while((n--)>0)
				{
					byte t=cp[7]; cp[7]=cp[0]; cp[0]=t;
					t=cp[6]; cp[6]=cp[1]; cp[1]=t;
					t=cp[5]; cp[5]=cp[2]; cp[2]=t;
					t=cp[4]; cp[4]=cp[3]; cp[3]=t;
					cp+=4;
				}
			}
		}

		// Bit reversal tables. TIFFBitRevTable[<byte>] gives
		// the bit reversed value of <byte>. Used in various
		// places in the library when the FillOrder requires
		// bit reversal of byte values (e.g. CCITT Fax 3
		// encoding/decoding). TIFFNoBitRevTable is provided
		// for algorithms that want an equivalent table that
		// do not reverse bit values.
		static readonly byte[] TIFFBitRevTable=new byte[256]
		{
			0x00, 0x80, 0x40, 0xc0, 0x20, 0xa0, 0x60, 0xe0,
			0x10, 0x90, 0x50, 0xd0, 0x30, 0xb0, 0x70, 0xf0,
			0x08, 0x88, 0x48, 0xc8, 0x28, 0xa8, 0x68, 0xe8,
			0x18, 0x98, 0x58, 0xd8, 0x38, 0xb8, 0x78, 0xf8,
			0x04, 0x84, 0x44, 0xc4, 0x24, 0xa4, 0x64, 0xe4,
			0x14, 0x94, 0x54, 0xd4, 0x34, 0xb4, 0x74, 0xf4,
			0x0c, 0x8c, 0x4c, 0xcc, 0x2c, 0xac, 0x6c, 0xec,
			0x1c, 0x9c, 0x5c, 0xdc, 0x3c, 0xbc, 0x7c, 0xfc,
			0x02, 0x82, 0x42, 0xc2, 0x22, 0xa2, 0x62, 0xe2,
			0x12, 0x92, 0x52, 0xd2, 0x32, 0xb2, 0x72, 0xf2,
			0x0a, 0x8a, 0x4a, 0xca, 0x2a, 0xaa, 0x6a, 0xea,
			0x1a, 0x9a, 0x5a, 0xda, 0x3a, 0xba, 0x7a, 0xfa,
			0x06, 0x86, 0x46, 0xc6, 0x26, 0xa6, 0x66, 0xe6,
			0x16, 0x96, 0x56, 0xd6, 0x36, 0xb6, 0x76, 0xf6,
			0x0e, 0x8e, 0x4e, 0xce, 0x2e, 0xae, 0x6e, 0xee,
			0x1e, 0x9e, 0x5e, 0xde, 0x3e, 0xbe, 0x7e, 0xfe,
			0x01, 0x81, 0x41, 0xc1, 0x21, 0xa1, 0x61, 0xe1,
			0x11, 0x91, 0x51, 0xd1, 0x31, 0xb1, 0x71, 0xf1,
			0x09, 0x89, 0x49, 0xc9, 0x29, 0xa9, 0x69, 0xe9,
			0x19, 0x99, 0x59, 0xd9, 0x39, 0xb9, 0x79, 0xf9,
			0x05, 0x85, 0x45, 0xc5, 0x25, 0xa5, 0x65, 0xe5,
			0x15, 0x95, 0x55, 0xd5, 0x35, 0xb5, 0x75, 0xf5,
			0x0d, 0x8d, 0x4d, 0xcd, 0x2d, 0xad, 0x6d, 0xed,
			0x1d, 0x9d, 0x5d, 0xdd, 0x3d, 0xbd, 0x7d, 0xfd,
			0x03, 0x83, 0x43, 0xc3, 0x23, 0xa3, 0x63, 0xe3,
			0x13, 0x93, 0x53, 0xd3, 0x33, 0xb3, 0x73, 0xf3,
			0x0b, 0x8b, 0x4b, 0xcb, 0x2b, 0xab, 0x6b, 0xeb,
			0x1b, 0x9b, 0x5b, 0xdb, 0x3b, 0xbb, 0x7b, 0xfb,
			0x07, 0x87, 0x47, 0xc7, 0x27, 0xa7, 0x67, 0xe7,
			0x17, 0x97, 0x57, 0xd7, 0x37, 0xb7, 0x77, 0xf7,
			0x0f, 0x8f, 0x4f, 0xcf, 0x2f, 0xaf, 0x6f, 0xef,
			0x1f, 0x9f, 0x5f, 0xdf, 0x3f, 0xbf, 0x7f, 0xff
		};

		static readonly byte[] TIFFNoBitRevTable=new byte[256]
		{
			0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
			0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
			0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
			0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
			0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
			0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
			0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
			0x38, 0x39, 0x3a, 0x3b, 0x3c, 0x3d, 0x3e, 0x3f,
			0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
			0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
			0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
			0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
			0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67,
			0x68, 0x69, 0x6a, 0x6b, 0x6c, 0x6d, 0x6e, 0x6f,
			0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
			0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f,
			0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
			0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
			0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
			0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f,
			0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
			0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf,
			0xb0, 0xb1, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7,
			0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
			0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7,
			0xc8, 0xc9, 0xca, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
			0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
			0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf,
			0xe0, 0xe1, 0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7,
			0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
			0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7,
			0xf8, 0xf9, 0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff,
		};

		public static byte[] TIFFGetBitRevTable(bool reversed)
		{
			return (reversed?TIFFBitRevTable:TIFFNoBitRevTable);
		}

		public unsafe static void TIFFReverseBits(byte[] cp0, uint n)
		{
			fixed(byte* cp_=cp0)
			{
				byte* cp=cp_;

				for(; n>8; n-=8)
				{
					cp[0]=TIFFBitRevTable[cp[0]];
					cp[1]=TIFFBitRevTable[cp[1]];
					cp[2]=TIFFBitRevTable[cp[2]];
					cp[3]=TIFFBitRevTable[cp[3]];
					cp[4]=TIFFBitRevTable[cp[4]];
					cp[5]=TIFFBitRevTable[cp[5]];
					cp[6]=TIFFBitRevTable[cp[6]];
					cp[7]=TIFFBitRevTable[cp[7]];
					cp+=8;
				}

				while((n--)>0)
				{
					*cp=TIFFBitRevTable[*cp];
					cp++;
				}
			}
		}

		public unsafe static void TIFFReverseBits(byte[] cp0, int cp0_offset, uint n)
		{
			fixed(byte* cp_=cp0)
			{
				byte* cp=cp_+cp0_offset;

				for(; n>8; n-=8)
				{
					cp[0]=TIFFBitRevTable[cp[0]];
					cp[1]=TIFFBitRevTable[cp[1]];
					cp[2]=TIFFBitRevTable[cp[2]];
					cp[3]=TIFFBitRevTable[cp[3]];
					cp[4]=TIFFBitRevTable[cp[4]];
					cp[5]=TIFFBitRevTable[cp[5]];
					cp[6]=TIFFBitRevTable[cp[6]];
					cp[7]=TIFFBitRevTable[cp[7]];
					cp+=8;
				}

				while((n--)>0)
				{
					*cp=TIFFBitRevTable[*cp];
					cp++;
				}
			}
		}
	}
}