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/* Copyright (C) 1995, 1996, 1997, 1998 Aladdin Enterprises. All rights reserved.
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This software is provided AS-IS with no warranty, either express or
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implied.
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This software is distributed under license and may not be copied,
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modified or distributed except as expressly authorized under the terms
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of the license contained in the file LICENSE in this distribution.
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For more information about licensing, please refer to
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http://www.ghostscript.com/licensing/. For information on
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commercial licensing, go to http://www.artifex.com/licensing/ or
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contact Artifex Software, Inc., 101 Lucas Valley Road #110,
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San Rafael, CA 94903, U.S.A., +1(415)492-9861.
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*/
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/* $Id: gsbittab.h,v 1.4 2002/02/21 22:24:52 giles Exp $ */
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/* Interface to tables for bit operations */
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#ifndef gsbittab_INCLUDED
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# define gsbittab_INCLUDED
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/*
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* Generate tables for transforming 2, 4, 6, or 8 bits.
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*/
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#define btab2_(v0,v2,v1)\
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v0,v1+v0,v2+v0,v2+v1+v0
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#define bit_table_2(v0,v2,v1) btab2_(v0,v2,v1)
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#define btab4_(v0,v8,v4,v2,v1)\
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btab2_(v0,v2,v1), btab2_(v4+v0,v2,v1),\
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btab2_(v8+v0,v2,v1), btab2_(v8+v4+v0,v2,v1)
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#define bit_table_4(v0,v8,v4,v2,v1) btab4_(v0,v8,v4,v2,v1)
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#define btab6_(v0,v20,v10,v8,v4,v2,v1)\
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btab4_(v0,v8,v4,v2,v1), btab4_(v10+v0,v8,v4,v2,v1),\
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btab4_(v20+v0,v8,v4,v2,v1), btab4_(v20+v10+v0,v8,v4,v2,v1)
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#define bit_table_6(v0,v20,v10,v8,v4,v2,v1) btab6_(v0,v20,v10,v8,v4,v2,v1)
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#define bit_table_8(v0,v80,v40,v20,v10,v8,v4,v2,v1)\
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btab6_(v0,v20,v10,v8,v4,v2,v1), btab6_(v40+v0,v20,v10,v8,v4,v2,v1),\
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btab6_(v80+v0,v20,v10,v8,v4,v2,v1), btab6_(v80+v40+v0,v20,v10,v8,v4,v2,v1)
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/*
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* byte_reverse_bits[B] = the byte B with the order of bits reversed.
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*/
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extern const byte byte_reverse_bits[256];
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/*
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* byte_right_mask[N] = a byte with N trailing 1s, 0 <= N <= 8.
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*/
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extern const byte byte_right_mask[9];
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/*
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* byte_count_bits[B] = the number of 1-bits in a byte with value B.
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*/
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extern const byte byte_count_bits[256];
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/*
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* byte_bit_run_length_N[B], for 0 <= N <= 7, gives the length of the
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* run of 1-bits starting at bit N in a byte with value B,
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* numbering the bits in the byte as 01234567. If the run includes
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* the low-order bit (i.e., might be continued into a following byte),
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* the run length is increased by 8.
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*/
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extern const byte
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byte_bit_run_length_0[256], byte_bit_run_length_1[256],
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byte_bit_run_length_2[256], byte_bit_run_length_3[256],
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byte_bit_run_length_4[256], byte_bit_run_length_5[256],
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byte_bit_run_length_6[256], byte_bit_run_length_7[256];
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/*
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* byte_bit_run_length[N] points to byte_bit_run_length_N.
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* byte_bit_run_length_neg[N] = byte_bit_run_length[-N & 7].
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*/
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extern const byte *const byte_bit_run_length[8];
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extern const byte *const byte_bit_run_length_neg[8];
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/*
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* byte_acegbdfh_to_abcdefgh[acegbdfh] = abcdefgh, where the letters
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* denote the individual bits of the byte.
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*/
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extern const byte byte_acegbdfh_to_abcdefgh[256];
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#endif /* gsbittab_INCLUDED */
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