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/* Copyright (C) 1994, 1995, 1999 Aladdin Enterprises. All rights reserved.
This software is licensed to a single customer by Artifex Software Inc.
under the terms of a specific OEM agreement.
*/
/*$RCSfile$ $Revision$ */
/* Definitions for PixelDifference filters */
/* Requires strimpl.h */
#ifndef spdiffx_INCLUDED
# define spdiffx_INCLUDED
/*
* Define the maximum value for Colors. This must be at least 4, but can
* be arbitrarily large: the only cost is a larger stream state structure.
*/
#define s_PDiff_max_Colors 16
/* PixelDifferenceDecode / PixelDifferenceEncode */
typedef struct stream_PDiff_state_s {
stream_state_common;
/* The client sets the following before initialization. */
int Colors; /* # of colors, 1..s_PDiff_max_Colors */
int BitsPerComponent; /* 1, 2, 4, 8 */
int Columns;
/* The init procedure computes the following. */
uint row_count; /* # of bytes per row */
byte end_mask; /* mask for left-over bits in last byte */
int case_index; /* switch index for case dispatch */
/* The following are updated dynamically. */
uint row_left; /* # of bytes left in row */
byte prev[s_PDiff_max_Colors]; /* previous sample */
} stream_PDiff_state;
#define private_st_PDiff_state() /* in spdiff.c */\
gs_private_st_simple(st_PDiff_state, stream_PDiff_state,\
"PixelDifferenceEncode/Decode state")
#define s_PDiff_set_defaults_inline(ss)\
((ss)->Colors = 1, (ss)->BitsPerComponent = 8, (ss)->Columns = 1)
extern const stream_template s_PDiffD_template;
extern const stream_template s_PDiffE_template;
#endif /* spdiffx_INCLUDED */
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