xref: /plan9-contrib/sys/src/cmd/gs/src/sdct.h (revision 593dc095aefb2a85c828727bbfa9da139a49bdf4)

/* Copyright (C) 1994, 1997, 1998 Aladdin Enterprises.  All rights reserved.

  This software is provided AS-IS with no warranty, either express or
  implied.

  This software is distributed under license and may not be copied,
  modified or distributed except as expressly authorized under the terms
  of the license contained in the file LICENSE in this distribution.

  For more information about licensing, please refer to
  http://www.ghostscript.com/licensing/. For information on
  commercial licensing, go to http://www.artifex.com/licensing/ or
  contact Artifex Software, Inc., 101 Lucas Valley Road #110,
  San Rafael, CA  94903, U.S.A., +1(415)492-9861.
*/

/* $Id: sdct.h,v 1.7 2002/06/16 05:00:54 lpd Exp $ */
/* Definitions for DCT filters */
/* Requires stream.h, strimpl.h, jpeg/jpeglib.h */

#ifndef sdct_INCLUDED
#  define sdct_INCLUDED

#include <setjmp.h>		/* for jmp_buf */

/* ------ DCT filters ------ */

/*
 * We don't want to allocate JPEG's private data directly from
 * the C heap, but we must allocate it as immovable; and to avoid
 * garbage collection issues, we must keep GC-traceable pointers
 * to every block allocated.
 */
typedef struct jpeg_block_s jpeg_block_t;
struct jpeg_block_s {
    jpeg_block_t *next;
    void *data;
};
#define private_st_jpeg_block()	/* in sjpegc.c */\
  gs_private_st_ptrs2(st_jpeg_block, jpeg_block_t, "jpeg_block_t",\
    jpeg_block_enum_ptrs, jpeg_block_reloc_ptrs, next, data)

/*
 * Define the stream state.
 * The jpeg_xxx_data structs are allocated in immovable memory
 * to simplify use of the IJG library.
 */
#define jpeg_stream_data_common\
		/* We put a copy of the stream template here, because */\
		/* the minimum buffer sizes depend on the image parameters. */\
	stream_template template;\
	struct jpeg_error_mgr err;\
	jmp_buf exit_jmpbuf;\
	gs_memory_t *memory;	/* heap for library allocations */\
        jpeg_block_t *blocks;   /* ptr to allocated data block list */\
		/* The following are documented in Adobe TN 5116. */\
	int Picky;		/* 0 or 1 */\
	int Relax		/* 0 or 1 */

typedef struct jpeg_stream_data_s {
    jpeg_stream_data_common;
} jpeg_stream_data;

/* Define initialization for the non-library part of the stream state. */
#define jpeg_stream_data_common_init(pdata)\
BEGIN\
  (pdata)->Picky = 0;\
  (pdata)->Relax = 0;\
  (pdata)->blocks = 0;\
END

typedef struct jpeg_compress_data_s {
    jpeg_stream_data_common;
    /* cinfo must immediately follow the common fields */
    struct jpeg_compress_struct cinfo;
    struct jpeg_destination_mgr destination;
    byte finish_compress_buf[100];
    int fcb_size, fcb_pos;
} jpeg_compress_data;

extern_st(st_jpeg_compress_data);
#define public_st_jpeg_compress_data()	/* in sdcte.c */\
  gs_public_st_ptrs1(st_jpeg_compress_data, jpeg_compress_data,\
    "JPEG compress data", jpeg_compress_data_enum_ptrs, jpeg_compress_data_reloc_ptrs, blocks)

typedef struct jpeg_decompress_data_s {
    jpeg_stream_data_common;
    /* dinfo must immediately follow the common fields, */
    /* so that it has same offset as cinfo. */
    struct jpeg_decompress_struct dinfo;
    struct jpeg_source_mgr source;
    long skip;			/* # of bytes remaining to skip in input */
    bool input_eod;		/* true when no more input data available */
    bool faked_eoi;		/* true when fill_input_buffer inserted EOI */
    byte *scanline_buffer;	/* buffer for oversize scanline, or NULL */
    uint bytes_in_scanline;	/* # of bytes remaining to output from same */
} jpeg_decompress_data;

#define private_st_jpeg_decompress_data()	/* in zfdctd.c */\
  gs_private_st_ptrs2(st_jpeg_decompress_data, jpeg_decompress_data,\
    "JPEG decompress data", jpeg_decompress_data_enum_ptrs,\
    jpeg_decompress_data_reloc_ptrs, blocks, scanline_buffer)

/* The stream state itself.  This is kept in garbage-collectable memory. */
typedef struct stream_DCT_state_s {
    stream_state_common;
    /* The following are set before initialization. */
    /* Note that most JPEG parameters go straight into */
    /* the IJG data structures, not into this struct. */
    gs_const_string Markers;	/* NULL if no Markers parameter */
    float QFactor;
    int ColorTransform;		/* -1 if not specified */
    bool NoMarker;		/* DCTEncode only */
    gs_memory_t *jpeg_memory;	/* heap for library allocations */
    /* This is a pointer to immovable storage. */
    union _jd {
	jpeg_stream_data *common;
	jpeg_compress_data *compress;
	jpeg_decompress_data *decompress;
    } data;
    /* DCTEncode sets this before initialization;
     * DCTDecode cannot set it until the JPEG headers are read.
     */
    uint scan_line_size;
    /* The following are updated dynamically. */
    int phase;
} stream_DCT_state;

/* The state descriptor is public only to allow us to split up */
/* the encoding and decoding filters. */
extern_st(st_DCT_state);
#define public_st_DCT_state()	/* in sdctc.c */\
  gs_public_st_const_strings1_ptrs1(st_DCT_state, stream_DCT_state,\
    "DCTEncode/Decode state", dct_enum_ptrs, dct_reloc_ptrs, Markers, data.common)
/*
 * NOTE: the client *must* invoke the set_defaults procedure in the
 * template before calling the init procedure.
 */
extern const stream_template s_DCTD_template;
extern const stream_template s_DCTE_template;

/* Define an internal procedure for setting stream defaults. */
/* Clients do not call this. */
void s_DCT_set_defaults(stream_state * st);

#endif /* sdct_INCLUDED */