/*

 * jpeglib.h

 *

 * Copyright (C) 1991-1998, 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 the application interface for the JPEG library.

 * Most applications using the library need only include this file,

 * and perhaps jerror.h if they want to know the exact error codes.

 */

#ifndef JPEGLIB_H

#define JPEGLIB_H

/*

 * First we include the configuration files that record how this

 * installation of the JPEG library is set up.  jconfig.h can be

 * generated automatically for many systems.  jmorecfg.h contains

 * manual configuration options that most people need not worry about.

 */

#ifndef JCONFIG_INCLUDED	/* in case jinclude.h already did */

#include "jconfig.h"		/* widely used configuration options */

#endif

#include "jmorecfg.h"		/* seldom changed options */

/* Version ID for the JPEG library.

 * Might be useful for tests like "#if JPEG_LIB_VERSION >= 60".

 */

#define JPEG_LIB_VERSION  62	/* Version 6b */

/* Various constants determining the sizes of things.

 * All of these are specified by the JPEG standard, so don't change them

 * if you want to be compatible.

 */

#define DCTSIZE		    8	/* The basic DCT block is 8x8 samples */

#define DCTSIZE2	    64	/* DCTSIZE squared; # of elements in a block */

#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 */

/* Unfortunately, some bozo at Adobe saw no reason to be bound by the standard;

 * the PostScript DCT filter can emit files with many more than 10 blocks/MCU.

 * If you happen to run across such a file, you can up D_MAX_BLOCKS_IN_MCU

 * to handle it.  We even let you do this from the jconfig.h file.  However,

 * we strongly discourage changing C_MAX_BLOCKS_IN_MCU; just because Adobe

 * sometimes emits noncompliant files doesn't mean you should too.

 */

#define C_MAX_BLOCKS_IN_MCU   10 /* compressor's limit on blocks per MCU */

#ifndef D_MAX_BLOCKS_IN_MCU

#define D_MAX_BLOCKS_IN_MCU   10 /* decompressor's limit on blocks per MCU */

#endif

/* Data structures for images (arrays of samples and of DCT coefficients).

 * 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 */

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 */

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

/* DCT coefficient quantization tables. */

typedef struct {

  /* This array gives the coefficient quantizers in natural array order

   * (not the zigzag order in which they are stored in a JPEG DQT marker).

   * CAUTION: IJG versions prior to v6a kept this array in zigzag order.

   */

  UINT16 quantval[DCTSIZE2];	/* quantization step for each coefficient */

  /* 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.

   * You could suppress output of a table by setting this to TRUE.

   * (See jpeg_suppress_tables for an example.)

   */

  boolean sent_table;		/* TRUE when table has been output */

} JQUANT_TBL;

/* Huffman coding tables. */

typedef struct {

  /* 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.

   * You could suppress output of a table by setting this to TRUE.

   * (See jpeg_suppress_tables for an example.)

   */

  boolean sent_table;		/* TRUE when table has been output */

} JHUFF_TBL;

/* Basic info about one component (color channel). */

typedef struct {

  /* These values are fixed over the whole image. */

  /* For compression, they must be supplied by parameter setup; */

  /* for decompression, they are read from the SOF marker. */

  int component_id;		/* identifier for this component (0..255) */

  int component_index;		/* its index in SOF or cinfo->comp_info[] */

  int h_samp_factor;		/* horizontal sampling factor (1..4) */

  int v_samp_factor;		/* vertical sampling factor (1..4) */

  int quant_tbl_no;		/* quantization table selector (0..3) */

  /* These values may vary between scans. */

  /* For compression, they must be supplied by parameter setup; */

  /* for decompression, they are read from the SOS marker. */

  /* The decompressor output side may not use these variables. */

  int dc_tbl_no;		/* DC entropy table selector (0..3) */

  int ac_tbl_no;		/* AC entropy table selector (0..3) */

  /* Remaining fields should be treated as private by applications. */

  /* These values are computed during compression or decompression startup: */

  /* Component's size in DCT blocks.

   * Any dummy blocks added to complete an MCU are not counted; therefore

   * these values do not depend on whether a scan is interleaved or not.

   */

  JDIMENSION width_in_blocks;

  JDIMENSION height_in_blocks;

  /* Size of a DCT block in samples.  Always DCTSIZE for compression.

   * For decompression this is the size of the output from one DCT block,

   * reflecting any scaling we choose to apply during the IDCT step.

   * Values of 1,2,4,8 are likely to be supported.  Note that different

   * components may receive different IDCT scalings.

   */

  int DCT_scaled_size;

  /* The downsampled dimensions are the component's actual, unpadded number

   * of samples at the main buffer (preprocessing/compression interface), thus

   * downsampled_width = ceil(image_width * Hi/Hmax)

   * and similarly for height.  For decompression, IDCT scaling is included, so

   * downsampled_width = ceil(image_width * Hi/Hmax * DCT_scaled_size/DCTSIZE)

   */

  JDIMENSION downsampled_width;	 /* actual width in samples */

  JDIMENSION downsampled_height; /* actual height in samples */

  /* This flag is used only for decompression.  In cases where some of the

   * components will be ignored (eg grayscale output from YCbCr image),

   * we can skip most computations for the unused components.

   */

  boolean component_needed;	/* do we need the value of this component? */

  /* These values are computed before starting a scan of the component. */

  /* The decompressor output side may not use these variables. */

  int MCU_width;		/* number of blocks per MCU, horizontally */

  int MCU_height;		/* number of blocks per MCU, vertically */

  int MCU_blocks;		/* MCU_width * MCU_height */

  int MCU_sample_width;		/* MCU width in samples, MCU_width*DCT_scaled_size */

  int last_col_width;		/* # of non-dummy blocks across in last MCU */

  int last_row_height;		/* # of non-dummy blocks down in last MCU */

  /* Saved quantization table for component; NULL if none yet saved.

   * See jdinput.c comments about the need for this information.

   * This field is currently used only for decompression.

   */

  JQUANT_TBL * quant_table;

  /* Private per-component storage for DCT or IDCT subsystem. */

  void * dct_table;

} jpeg_component_info;

/* The script for encoding a multiple-scan file is an array of these: */

typedef struct {

  int comps_in_scan;		/* number of components encoded in this scan */

  int component_index[MAX_COMPS_IN_SCAN]; /* their SOF/comp_info[] indexes */

  int Ss, Se;			/* progressive JPEG spectral selection parms */

  int Ah, Al;			/* progressive JPEG successive approx. parms */

} jpeg_scan_info;

/* The decompressor can save APPn and COM markers in a list of these: */

typedef struct jpeg_marker_struct FAR * jpeg_saved_marker_ptr;

struct jpeg_marker_struct {

  jpeg_saved_marker_ptr next;	/* next in list, or NULL */

  UINT8 marker;			/* marker code: JPEG_COM, or JPEG_APP0+n */

  unsigned int original_length;	/* # bytes of data in the file */

  unsigned int data_length;	/* # bytes of data saved at data[] */

  JOCTET FAR * data;		/* the data contained in the marker */

  /* the marker length word is not counted in data_length or original_length */

};

/* Known color spaces. */

typedef enum {

	JCS_UNKNOWN,		/* error/unspecified */

	JCS_GRAYSCALE,		/* monochrome */

	JCS_RGB,		/* red/green/blue */

	JCS_YCbCr,		/* Y/Cb/Cr (also known as YUV) */

	JCS_CMYK,		/* C/M/Y/K */

	JCS_YCCK		/* Y/Cb/Cr/K */

} J_COLOR_SPACE;

/* DCT/IDCT algorithm options. */

typedef enum {

	JDCT_ISLOW,		/* slow but accurate integer algorithm */

	JDCT_IFAST,		/* faster, less accurate integer method */

	JDCT_FLOAT		/* floating-point: accurate, fast on fast HW */

} J_DCT_METHOD;

#ifndef JDCT_DEFAULT		/* may be overridden in jconfig.h */

#define JDCT_DEFAULT  JDCT_ISLOW

#endif

#ifndef JDCT_FASTEST		/* may be overridden in jconfig.h */

#define JDCT_FASTEST  JDCT_IFAST

#endif

/* Dithering options for decompression. */

typedef enum {

	JDITHER_NONE,		/* no dithering */

	JDITHER_ORDERED,	/* simple ordered dither */

	JDITHER_FS		/* Floyd-Steinberg error diffusion dither */

} J_DITHER_MODE;

/* Common fields between JPEG compression and decompression master structs. */

#define jpeg_common_fields \

  struct jpeg_error_mgr * err;	/* Error handler module */\

  struct jpeg_memory_mgr * mem;	/* Memory manager module */\

  struct jpeg_progress_mgr * progress; /* Progress monitor, or NULL if none */\

  void * client_data;		/* Available for use by application */\

  boolean is_decompressor;	/* So common code can tell which is which */\

  int global_state		/* For checking call sequence validity */

/* Routines that are to be used by both halves of the library are declared

 * to receive a pointer to this structure.  There are no actual instances of

 * jpeg_common_struct, only of jpeg_compress_struct and jpeg_decompress_struct.

 */

struct jpeg_common_struct {

  jpeg_common_fields;		/* Fields common to both master struct types */

  /* Additional fields follow in an actual jpeg_compress_struct or

   * jpeg_decompress_struct.  All three structs must agree on these

   * initial fields!  (This would be a lot cleaner in C++.)

   */

};

typedef struct jpeg_common_struct * j_common_ptr;

typedef struct jpeg_compress_struct * j_compress_ptr;

typedef struct jpeg_decompress_struct * j_decompress_ptr;

/* Master record for a compression instance */

struct jpeg_compress_struct {

  jpeg_common_fields;		/* Fields shared with jpeg_decompress_struct */

  /* Destination for compressed data */

  struct jpeg_destination_mgr * dest;

  /* Description of source image --- these fields must be filled in by

   * outer application before starting compression.  in_color_space must

   * be correct before you can even call jpeg_set_defaults().

   */

  JDIMENSION image_width;	/* input image width */

  JDIMENSION image_height;	/* input image height */

  int input_components;		/* # of color components in input image */

  J_COLOR_SPACE in_color_space;	/* colorspace of input image */

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

  /* Compression parameters --- these fields must be set before calling

   * jpeg_start_compress().  We recommend calling jpeg_set_defaults() to

   * initialize everything to reasonable defaults, then changing anything

   * the application specifically wants to change.  That way you won't get

   * burnt when new parameters are added.  Also note that there are several

   * helper routines to simplify changing parameters.

   */

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

  int num_components;		/* # of color components in JPEG image */

  J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */

  jpeg_component_info * comp_info;

  /* comp_info[i] describes component that appears i'th in SOF */

  JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];

  /* ptrs to coefficient quantization tables, or NULL if not defined */

  JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];

  JHUFF_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 arith-coding tables */

  UINT8 arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */

  UINT8 arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */

  int num_scans;		/* # of entries in scan_info array */

  const jpeg_scan_info * scan_info; /* script for multi-scan file, or NULL */

  /* The default value of scan_info is NULL, which causes a single-scan

   * sequential JPEG file to be emitted.  To create a multi-scan file,

   * set num_scans and scan_info to point to an array of scan definitions.

   */

  boolean raw_data_in;		/* TRUE=caller supplies downsampled data */

  boolean arith_code;		/* TRUE=arithmetic coding, FALSE=Huffman */

  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 */

  J_DCT_METHOD dct_method;	/* DCT algorithm selector */

  /* 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).

   */

  unsigned int restart_interval; /* MCUs per restart, or 0 for no restart */

  int restart_in_rows;		/* if > 0, MCU rows per restart interval */

  /* Parameters controlling emission of special markers. */

  boolean write_JFIF_header;	/* should a JFIF marker be written? */

  UINT8 JFIF_major_version;	/* What to write for the JFIF version number */

  UINT8 JFIF_minor_version;

  /* These three values are not used by the JPEG code, merely 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 */

  boolean write_Adobe_marker;	/* should an Adobe marker be written? */

  /* State variable: index of next scanline to be written to

   * jpeg_write_scanlines().  Application may use this to control its

   * processing loop, e.g., "while (next_scanline < image_height)".

   */

  JDIMENSION next_scanline;	/* 0 .. image_height-1  */

  /* Remaining fields are known throughout compressor, but generally

   * should not be touched by a surrounding application.

   */

  /*

   * These fields are computed during compression startup

   */

  boolean progressive_mode;	/* TRUE if scan script uses progressive mode */

  int max_h_samp_factor;	/* largest h_samp_factor */

  int max_v_samp_factor;	/* largest v_samp_factor */

  JDIMENSION total_iMCU_rows;	/* # of iMCU rows to be input to coef ctlr */

  /* The coefficient controller receives data in units of MCU rows as defined

   * for fully interleaved scans (whether the JPEG file is interleaved or not).

   * There are v_samp_factor * DCTSIZE sample rows of each component in an

   * "iMCU" (interleaved MCU) row.

   */

  /*

   * These fields are valid during any one scan.

   * They describe the components and MCUs actually appearing in the scan.

   */

  int comps_in_scan;		/* # of JPEG components in this scan */

  jpeg_component_info * cur_comp_info[MAX_COMPS_IN_SCAN];

  /* *cur_comp_info[i] describes component that appears i'th in SOS */

  JDIMENSION MCUs_per_row;	/* # of MCUs across the image */

  JDIMENSION MCU_rows_in_scan;	/* # of MCU rows in the image */

  int blocks_in_MCU;		/* # of DCT blocks per MCU */

  int MCU_membership[C_MAX_BLOCKS_IN_MCU];

  /* MCU_membership[i] is index in cur_comp_info of component owning */

  /* i'th block in an MCU */

  int Ss, Se, Ah, Al;		/* progressive JPEG parameters for scan */

  /*

   * Links to compression subobjects (methods and private variables of modules)

   */

  struct jpeg_comp_master * master;

  struct jpeg_c_main_controller * main;

  struct jpeg_c_prep_controller * prep;

  struct jpeg_c_coef_controller * coef;

  struct jpeg_marker_writer * marker;

  struct jpeg_color_converter * cconvert;

  struct jpeg_downsampler * downsample;

  struct jpeg_forward_dct * fdct;

  struct jpeg_entropy_encoder * entropy;

  jpeg_scan_info * script_space; /* workspace for jpeg_simple_progression */

  int script_space_size;

};

/* Master record for a decompression instance */

struct jpeg_decompress_struct {

  jpeg_common_fields;		/* Fields shared with jpeg_compress_struct */

  /* Source of compressed data */

  struct jpeg_source_mgr * src;

  /* Basic description of image --- filled in by jpeg_read_header(). */

  /* Application may inspect these values to decide how to process image. */

  JDIMENSION image_width;	/* nominal image width (from SOF marker) */

  JDIMENSION image_height;	/* nominal image height */

  int num_components;		/* # of color components in JPEG image */

  J_COLOR_SPACE jpeg_color_space; /* colorspace of JPEG image */

  /* Decompression processing parameters --- these fields must be set before

   * calling jpeg_start_decompress().  Note that jpeg_read_header() initializes

   * them to default values.

   */

  J_COLOR_SPACE out_color_space; /* colorspace for output */

  unsigned int scale_num, scale_denom; /* fraction by which to scale image */

  double output_gamma;		/* image gamma wanted in output */

  boolean buffered_image;	/* TRUE=multiple output passes */

  boolean raw_data_out;		/* TRUE=downsampled data wanted */

  J_DCT_METHOD dct_method;	/* IDCT algorithm selector */

  boolean do_fancy_upsampling;	/* TRUE=apply fancy upsampling */

  boolean do_block_smoothing;	/* TRUE=apply interblock smoothing */

  boolean quantize_colors;	/* TRUE=colormapped output wanted */

  /* the following are ignored if not quantize_colors: */

  J_DITHER_MODE dither_mode;	/* type of color dithering to use */

  boolean two_pass_quantize;	/* TRUE=use two-pass color quantization */

  int desired_number_of_colors;	/* max # colors to use in created colormap */

  /* these are significant only in buffered-image mode: */

  boolean enable_1pass_quant;	/* enable future use of 1-pass quantizer */

  boolean enable_external_quant;/* enable future use of external colormap */

  boolean enable_2pass_quant;	/* enable future use of 2-pass quantizer */

  /* Description of actual output image that will be returned to application.

   * These fields are computed by jpeg_start_decompress().

   * You can also use jpeg_calc_output_dimensions() to determine these values

   * in advance of calling jpeg_start_decompress().

   */

  JDIMENSION output_width;	/* scaled image width */

  JDIMENSION output_height;	/* scaled image height */

  int out_color_components;	/* # of color components in out_color_space */

  int output_components;	/* # of color components returned */

  /* output_components is 1 (a colormap index) when quantizing colors;

   * otherwise it equals out_color_components.

   */

  int rec_outbuf_height;	/* min recommended height of scanline buffer */

  /* If the buffer passed to jpeg_read_scanlines() is less than this many rows

   * high, space and time will be wasted due to unnecessary data copying.

   * Usually rec_outbuf_height will be 1 or 2, at most 4.

   */

  /* When quantizing colors, the output colormap is described by these fields.

   * The application can supply a colormap by setting colormap non-NULL before

   * calling jpeg_start_decompress; otherwise a colormap is created during

   * jpeg_start_decompress or jpeg_start_output.

   * The map has out_color_components rows and actual_number_of_colors columns.

   */

  int actual_number_of_colors;	/* number of entries in use */

  JSAMPARRAY colormap;		/* The color map as a 2-D pixel array */

  /* State variables: these variables indicate the progress of decompression.

   * The application may examine these but must not modify them.

   */

  /* Row index of next scanline to be read from jpeg_read_scanlines().

   * Application may use this to control its processing loop, e.g.,

   * "while (output_scanline < output_height)".

   */

  JDIMENSION output_scanline;	/* 0 .. output_height-1  */

  /* Current input scan number and number of iMCU rows completed in scan.

   * These indicate the progress of the decompressor input side.

   */

  int input_scan_number;	/* Number of SOS markers seen so far */

  JDIMENSION input_iMCU_row;	/* Number of iMCU rows completed */

  /* The "output scan number" is the notional scan being displayed by the

   * output side.  The decompressor will not allow output scan/row number

   * to get ahead of input scan/row, but it can fall arbitrarily far behind.

   */

  int output_scan_number;	/* Nominal scan number being displayed */

  JDIMENSION output_iMCU_row;	/* Number of iMCU rows read */

  /* Current progression status.  coef_bits[c][i] indicates the precision

   * with which component c's DCT coefficient i (in zigzag order) is known.

   * It is -1 when no data has yet been received, otherwise it is the point

   * transform (shift) value for the most recent scan of the coefficient

   * (thus, 0 at completion of the progression).

   * This pointer is NULL when reading a non-progressive file.

   */

  int (*coef_bits)[DCTSIZE2];	/* -1 or current Al value for each coef */

  /* Internal JPEG parameters --- the application usually need not look at

   * these fields.  Note that the decompressor output side may not use

   * any parameters that can change between scans.

   */

  /* Quantization and Huffman tables are carried forward across input

   * datastreams when processing abbreviated JPEG datastreams.

   */

  JQUANT_TBL * quant_tbl_ptrs[NUM_QUANT_TBLS];

  /* ptrs to coefficient quantization tables, or NULL if not defined */

  JHUFF_TBL * dc_huff_tbl_ptrs[NUM_HUFF_TBLS];

  JHUFF_TBL * ac_huff_tbl_ptrs[NUM_HUFF_TBLS];

  /* ptrs to Huffman coding tables, or NULL if not defined */