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/* Copyright (C) 1996, 1999 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: spngpx.h,v 1.4 2002/02/21 22:24:54 giles Exp $ */
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/* Definitions for PNGPredictor filters */
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/* Requires strimpl.h */
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#ifndef spngpx_INCLUDED
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# define spngpx_INCLUDED
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/* PNGPredictorDecode / PNGPredictorEncode */
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typedef struct stream_PNGP_state_s {
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stream_state_common;
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/* The client sets the following before initialization. */
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int Colors; /* # of colors, 1..16 */
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int BitsPerComponent; /* 1, 2, 4, 8, 16 */
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uint Columns; /* >0 */
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int Predictor; /* 10-15, only relevant for Encode */
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/* The init procedure computes the following. */
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uint row_count; /* # of bytes per row */
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byte end_mask; /* mask for left-over bits in last byte */
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int bpp; /* bytes per pixel */
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byte *prev_row; /* previous row */
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int case_index; /* switch index for case dispatch, */
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/* set dynamically when decoding */
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/* The following are updated dynamically. */
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long row_left; /* # of bytes left in row */
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byte prev[32]; /* previous samples */
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} stream_PNGP_state;
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#define private_st_PNGP_state() /* in sPNGP.c */\
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gs_private_st_ptrs1(st_PNGP_state, stream_PNGP_state,\
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"PNGPredictorEncode/Decode state", pngp_enum_ptrs, pngp_reloc_ptrs,\
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prev_row)
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#define s_PNGP_set_defaults_inline(ss)\
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((ss)->Colors = 1, (ss)->BitsPerComponent = 8, (ss)->Columns = 1,\
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(ss)->Predictor = 15,\
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/* Clear pointers */\
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(ss)->prev_row = 0)
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extern const stream_template s_PNGPD_template;
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extern const stream_template s_PNGPE_template;
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#endif /* spngpx_INCLUDED */
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