jpegdata.h

EVM板JPEG实现,Texas Instruments TMS320C54x EVM JPEG

/*
 * jpegdata.h
 *
 * Copyright (C) 1991, 1992, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file defines shared data structures for the various JPEG modules.
 */


/*
 * You might need to change some of the following declarations if you are
 * using the JPEG software within a surrounding application program
 * or porting it to an unusual system.
 */


/* If the source or destination of image data is not to be stdio streams,
 * these types may need work.  You can replace them with some kind of
 * pointer or indicator that is useful to you, or just ignore 'em.
 * Note that the user interface and the various jrdxxx/jwrxxx modules
 * will also need work for non-stdio input/output.
 */
typedef int FILE;

typedef FILE * JFILEREF;      /* source or dest of JPEG-compressed data */

typedef FILE * IFILEREF;	/* source or dest of non-JPEG image data */


/* These defines are used in all function definitions and extern declarations.
 * You could modify them if you need to change function linkage conventions,
 * as is shown below for use with C++.  Another application would be to make
 * all functions global for use with code profilers that require it.
 * NOTE: the C++ test does the right thing if you are reading this include
 * file in a C++ application to link to JPEG code that's been compiled with a
 * regular C compiler.  I'm not sure it works if you try to compile the JPEG
 * code with C++.
 */

#define METHODDEF static	/* a function called through method pointers */
#define LOCAL	  static	/* a function used only in its module */
#define GLOBAL			/* a function referenced thru EXTERNs */
#ifdef __cplusplus
#define EXTERN	  extern "C"	/* a reference to a GLOBAL function */
#else
#define EXTERN	  extern	/* a reference to a GLOBAL function */
#endif


/* Here is the pseudo-keyword for declaring pointers that must be "far"
 * on 80x86 machines.  Most of the specialized coding for 80x86 is handled
 * by just saying "FAR *" where such a pointer is needed.  In a few places
 * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol.
 */

#ifdef NEED_FAR_POINTERS
#define FAR  far
#else
#define FAR
#endif



/* The remaining declarations are not system-dependent, we hope. */


/*
 * NOTE: if you have an ancient, strict-K&R C compiler, it may choke on the
 * similarly-named fields in Compress_info_struct and Decompress_info_struct.
 * If this happens, you can get around it by rearranging the two structs so
 * that the similarly-named fields appear first and in the same order in
 * each struct.  Since such compilers are now pretty rare, we haven't done
 * this in the portable code, preferring to maintain a logical ordering.
 */



/* This macro is used to declare a "method", that is, a function pointer. */
/* We want to supply prototype parameters if the compiler can cope. */
/* Note that the arglist parameter must be parenthesized! */

#ifdef PROTO
#define METHOD(type,methodname,arglist)  type (*methodname) arglist
#else
#define METHOD(type,methodname,arglist)  type (*methodname) ()
#endif

/* Forward references to lists of method pointers */
typedef struct External_methods_struct * external_methods_ptr;
typedef struct Compress_methods_struct * compress_methods_ptr;
typedef struct Decompress_methods_struct * decompress_methods_ptr;


/* Data structures for images containing either samples or coefficients. */
/* Note that the topmost (leftmost) index is always color component. */
/* On 80x86 machines, the image arrays are too big for near pointers, */
/* but the pointer arrays can fit in near memory. */

typedef JSAMPLE FAR *JSAMPROW;	/* ptr to one image row of pixel samples. */
typedef JSAMPROW *JSAMPARRAY;	/* ptr to some rows (a 2-D sample array) */
typedef JSAMPARRAY *JSAMPIMAGE;	/* a 3-D sample array: top index is color */


#define DCTSIZE		8	/* The basic DCT block is 8x8 samples */
#define DCTSIZE2	64	/* DCTSIZE squared; # of elements in a block */

typedef JCOEF JBLOCK[DCTSIZE2];	/* one block of coefficients */
typedef JBLOCK FAR *JBLOCKROW;	/* pointer to one row of coefficient blocks */
typedef JBLOCKROW *JBLOCKARRAY;		/* a 2-D array of coefficient blocks */
typedef JBLOCKARRAY *JBLOCKIMAGE;	/* a 3-D array of coefficient blocks */

typedef JCOEF FAR *JCOEFPTR;	/* useful in a couple of places */


/* The input and output data of the DCT transform subroutines are of
 * the following type, which need not be the same as JCOEF.
 * For example, on a machine with fast floating point, it might make sense
 * to recode the DCT routines to use floating point; then DCTELEM would be
 * 'float' or 'double'.
 */

typedef JCOEF DCTELEM;
typedef DCTELEM DCTBLOCK[DCTSIZE2];


/* Types for JPEG compression parameters and working tables. */


typedef enum {			/* defines known color spaces */
	CS_UNKNOWN,		/* error/unspecified */
	CS_GRAYSCALE,		/* monochrome (only 1 component) */
	CS_RGB,			/* red/green/blue */
	CS_YCbCr,		/* Y/Cb/Cr (also known as YUV) */
	CS_YIQ,			/* Y/I/Q */
	CS_CMYK			/* C/M/Y/K */
} COLOR_SPACE;


typedef struct {		/* Basic info about one component */
  /* These values are fixed over the whole image */
  /* For compression, they must be supplied by the user interface; */
  /* for decompression, they are read from the SOF marker. */
	short component_id;	/* identifier for this component (0..255) */
	short component_index;	/* its index in SOF or cinfo->comp_info[] */
	short h_samp_factor;	/* horizontal sampling factor (1..4) */
	short v_samp_factor;	/* vertical sampling factor (1..4) */
	short quant_tbl_no;	/* quantization table selector (0..3) */
  /* These values may vary between scans */
  /* For compression, they must be supplied by the user interface; */
  /* for decompression, they are read from the SOS marker. */
	short dc_tbl_no;	/* DC entropy table selector (0..3) */
	short ac_tbl_no;	/* AC entropy table selector (0..3) */
  /* These values are computed during compression or decompression startup */
	long true_comp_width;	/* component's image width in samples */
	long true_comp_height;	/* component's image height in samples */
	/* the above are the logical dimensions of the downsampled image */
  /* These values are computed before starting a scan of the component */
	short MCU_width;	/* number of blocks per MCU, horizontally */
	short MCU_height;	/* number of blocks per MCU, vertically */
	short MCU_blocks;	/* MCU_width * MCU_height */
	long downsampled_width;	/* image width in samples, after expansion */
	long downsampled_height; /* image height in samples, after expansion */
	/* the above are the true_comp_xxx values rounded up to multiples of */
	/* the MCU dimensions; these are the working dimensions of the array */
	/* as it is passed through the DCT or IDCT step.  NOTE: these values */
	/* differ depending on whether the component is interleaved or not!! */
} jpeg_component_info;


/* DCT coefficient quantization tables.
 * For 8-bit precision, 'INT16' should be good enough for quantization values;
 * for more precision, we go for the full 16 bits.  'INT16' provides a useful
 * speedup on many machines (multiplication & division of JCOEFs by
 * quantization values is a significant chunk of the runtime).
 * Note: the values in a QUANT_TBL are always given in zigzag order.
 */
#ifdef EIGHT_BIT_SAMPLES
typedef INT16 QUANT_VAL;	/* element of a quantization table */
#else
typedef UINT16 QUANT_VAL;	/* element of a quantization table */
#endif
typedef QUANT_VAL QUANT_TBL[DCTSIZE2];	/* A quantization table */
typedef QUANT_VAL * QUANT_TBL_PTR;	/* pointer to same */


typedef struct {		/* A Huffman coding table */
  /* These two fields directly represent the contents of a JPEG DHT marker */
	UINT8 bits[17];		/* bits[k] = # of symbols with codes of */
				/* length k bits; bits[0] is unused */
	UINT8 huffval[256];	/* The symbols, in order of incr code length */
  /* This field is used only during compression.  It's initialized FALSE when
   * the table is created, and set TRUE when it's been output to the file.
   */
	boolean sent_table;	/* TRUE when table has been output */
  /* The remaining fields are computed from the above to allow more efficient
   * coding and decoding.  These fields should be considered private to the
   * Huffman compression & decompression modules.
   */
	/* encoding tables: */
	UINT16 ehufco[256];	/* code for each symbol */
	char ehufsi[256];	/* length of code for each symbol */
	/* decoding tables: (element [0] of each array is unused) */
	UINT16 mincode[17];	/* smallest code of length k */
	INT32 maxcode[18];	/* largest code of length k (-1 if none) */
	/* (maxcode[17] is a sentinel to ensure huff_DECODE terminates) */
	short valptr[17];	/* huffval[] index of 1st symbol of length k */
} HUFF_TBL;


#define NUM_QUANT_TBLS      4	/* quantization tables are numbered 0..3 */
#define NUM_HUFF_TBLS       4	/* Huffman tables are numbered 0..3 */
#define NUM_ARITH_TBLS      16	/* arith-coding tables are numbered 0..15 */
#define MAX_COMPS_IN_SCAN   4	/* JPEG limit on # of components in one scan */
#define MAX_SAMP_FACTOR     4	/* JPEG limit on sampling factors */
#define MAX_BLOCKS_IN_MCU   10	/* JPEG limit on # of blocks in an MCU */


/* Working data for compression */

struct Compress_info_struct {
/*
 * All of these fields shall be established by the user interface before
 * calling jpeg_compress, or by the input_init or c_ui_method_selection
 * methods.
 * Most parameters can be set to reasonable defaults by j_c_defaults.
 * Note that the UI must supply the storage for the main methods struct,
 * though it sets only a few of the methods there.
 */
	compress_methods_ptr methods; /* Points to list of methods to use */

	external_methods_ptr emethods; /* Points to list of methods to use */

	IFILEREF input_file;	/* tells input routines where to read image */
	JFILEREF output_file;	/* tells output routines where to write JPEG */

	long image_width;	/* input image width */
	long image_height;	/* input image height */
	short input_components;	/* # of color components in input image */

	short data_precision;	/* bits of precision in image data */

	COLOR_SPACE in_color_space; /* colorspace of input file */
	COLOR_SPACE jpeg_color_space; /* colorspace of JPEG file */

	double input_gamma;	/* image gamma of input file */

	boolean write_JFIF_header; /* should a JFIF marker be written? */
	/* These three values are not used by the JPEG code, only copied */
	/* into the JFIF APP0 marker.  density_unit can be 0 for unknown, */
	/* 1 for dots/inch, or 2 for dots/cm.  Note that the pixel aspect */
	/* ratio is defined by X_density/Y_density even when density_unit=0. */
	UINT8 density_unit;	/* JFIF code for pixel size units */
	UINT16 X_density;	/* Horizontal pixel density */
	UINT16 Y_density;	/* Vertical pixel density */

	short num_components;	/* # of color components in JPEG image */
	jpeg_component_info * comp_info;
	/* comp_info[i] describes component that appears i'th in SOF */

	QUANT_TBL_PTR quant_tbl_ptrs[NUM_QUANT_TBLS];
	/* ptrs to coefficient quantization tables, or NULL if not defined */

	HUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];
	HUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];
	/* ptrs to Huffman coding tables, or NULL if not defined */

	UINT8 arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arithmetic-coding tables */
	UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arithmetic-coding tables */
	UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arithmetic-coding tables */

	boolean arith_code;	/* TRUE=arithmetic coding, FALSE=Huffman */
	boolean interleave;	/* TRUE=interleaved output, FALSE=not */
	boolean optimize_coding; /* TRUE=optimize entropy encoding parms */
	boolean CCIR601_sampling; /* TRUE=first samples are cosited */
	int smoothing_factor;	/* 1..100, or 0 for no input smoothing */

	/* The restart interval can be specified in absolute MCUs by setting
	 * restart_interval, or in MCU rows by setting restart_in_rows
	 * (in which case the correct restart_interval will be figured
	 * for each scan).
	 */
	UINT16 restart_interval;/* MCUs per restart interval, or 0 for no restart */
	int restart_in_rows;	/* if > 0, MCU rows per restart interval */

/*
 * These fields are computed during jpeg_compress startup
 */
	short max_h_samp_factor; /* largest h_samp_factor */
	short max_v_samp_factor; /* largest v_samp_factor */

/*
 * These fields may be useful for progress monitoring
 */

	int total_passes;	/* number of passes expected */
	int completed_passes;	/* number of passes completed so far */

/*
 * These fields are valid during any one scan
 */
	short comps_in_scan;	/* # of JPEG components output this time */
	jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];
	/* *cur_comp_info[i] describes component that appears i'th in SOS */

	long MCUs_per_row;	/* # of MCUs across the image */
	long MCU_rows_in_scan;	/* # of MCU rows in the image */

	short blocks_in_MCU;	/* # of DCT blocks per MCU */
	short MCU_membership[MAX_BLOCKS_IN_MCU];