    /*
     * 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.
       */
      unsigned short 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.)
       */
      int 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 */
      unsigned char bits[17];		/* bits[k] = # of symbols with codes of */
    				/* length k bits; bits[0] is unused */
      unsigned char 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.)
       */
      int 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.
       */
      int 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 */
      unsigned char 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 */\
      int 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 */

      unsigned char arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
      unsigned char arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
      unsigned char 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.
       */

      int raw_data_in;		/* TRUE=caller supplies downsampled data */
      int arith_code;		/* TRUE=arithmetic coding, FALSE=Huffman */
      int optimize_coding;	/* TRUE=optimize entropy encoding parms */
      int 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. */

      int write_JFIF_header;	/* should a JFIF marker be written? */
      unsigned char JFIF_major_version;	/* What to write for the JFIF version number */
      unsigned char 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. */
      unsigned char density_unit;		/* JFIF code for pixel size units */
      unsigned short X_density;		/* Horizontal pixel density */
      unsigned short Y_density;		/* Vertical pixel density */
      int 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
       */
      int 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 */

      int buffered_image;	/* TRUE=multiple output passes */
      int raw_data_out;		/* TRUE=downsampled data wanted */

      J_DCT_METHOD dct_method;	/* IDCT algorithm selector */
      int do_fancy_upsampling;	/* TRUE=apply fancy upsampling */
      int do_block_smoothing;	/* TRUE=apply interblock smoothing */

      int 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 */
      int 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: */
      int enable_1pass_quant;	/* enable future use of 1-pass quantizer */
      int enable_external_quant;/* enable future use of external colormap */
      int 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 */

      /* These parameters are never carried across datastreams, since they
       * are given in SOF/SOS markers or defined to be reset by SOI.
       */

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

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

      int progressive_mode;	/* TRUE if SOFn specifies progressive mode */
      int arith_code;		/* TRUE=arithmetic coding, FALSE=Huffman */

      unsigned char arith_dc_L[NUM_ARITH_TBLS]; /* L values for DC arith-coding tables */
      unsigned char arith_dc_U[NUM_ARITH_TBLS]; /* U values for DC arith-coding tables */
      unsigned char arith_ac_K[NUM_ARITH_TBLS]; /* Kx values for AC arith-coding tables */

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

      /* These fields record data obtained from optional markers recognized by
       * the JPEG library.
       */
      int saw_JFIF_marker;	/* TRUE iff a JFIF APP0 marker was found */
      /* Data copied from JFIF marker; only valid if saw_JFIF_marker is TRUE: */
      unsigned char JFIF_major_version;	/* JFIF version number */
      unsigned char JFIF_minor_version;
      unsigned char density_unit;		/* JFIF code for pixel size units */
      unsigned short X_density;		/* Horizontal pixel density */
      unsigned short Y_density;		/* Vertical pixel density */
      int saw_Adobe_marker;	/* TRUE iff an Adobe APP14 marker was found */
      unsigned char Adobe_transform;	/* Color transform code from Adobe marker */

      int CCIR601_sampling;	/* TRUE=first samples are cosited */

      /* Aside from the specific data retained from APPn markers known to the
       * library, the uninterpreted contents of any or all APPn and COM markers
       * can be saved in a list for examination by the application.
       */
      jpeg_saved_marker_ptr marker_list; /* Head of list of saved markers */

      /* Remaining fields are known throughout decompressor, but generally
       * should not be touched by a surrounding application.
       */

      /*
       * These fields are computed during decompression startup
       */
      int max_h_samp_factor;	/* largest h_samp_factor */
      int max_v_samp_factor;	/* largest v_samp_factor */

      int min_DCT_scaled_size;	/* smallest DCT_scaled_size of any component */

      JDIMENSION total_iMCU_rows;	/* # of iMCU rows in image */
      /* The coefficient controller's input and output progress is measured in
       * units of "iMCU" (interleaved MCU) rows.  These are the same as MCU rows
       * in fully interleaved JPEG scans, but are used whether the scan is
       * interleaved or not.  We define an iMCU row as v_samp_factor DCT block
       * rows of each component.  Therefore, the IDCT output contains
       * v_samp_factor*DCT_scaled_size sample rows of a component per iMCU row.
       */

      JSAMPLE * sample_range_limit; /* table for fast range-limiting */

      /*
       * These fields are valid during any one scan.
       * They describe the components and MCUs actually appearing in the scan.
       * Note that the decompressor output side must not use these fields.
       */
      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[D_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 */

      /* This field is shared between entropy decoder and marker parser.
       * It is either zero or the code of a JPEG marker that has been
       * read from the data source, but has not yet been processed.
       */
      int unread_marker;

      /*
       * Links to decompression subobjects (methods, private variables of modules)
       */
      struct jpeg_decomp_master * master;
      struct jpeg_d_main_controller * main;
      struct jpeg_d_coef_controller * coef;
      struct jpeg_d_post_controller * post;
      struct jpeg_input_controller * inputctl;
      struct jpeg_marker_reader * marker;
      struct jpeg_entropy_decoder * entropy;
      struct jpeg_inverse_dct * idct;
      struct jpeg_upsampler * upsample;
      struct jpeg_color_deconverter * cconvert;
      struct jpeg_color_quantizer * cquantize;
    };

    /* "Object" declarations for JPEG modules that may be supplied or called
     * directly by the surrounding application.
     * As with all objects in the JPEG library, these structs only define the
     * publicly visible methods and state variables of a module.  Additional
     * private fields may exist after the public ones.
     */

    /* Error handler object */

    struct jpeg_error_mgr {
      /* Error exit handler: does not return to caller */
      JMETHOD(void, error_exit, (j_common_ptr cinfo));
      /* Conditionally emit a trace or warning message */
      JMETHOD(void, emit_message, (j_common_ptr cinfo, int msg_level));
      /* Routine that actually outputs a trace or error message */
      JMETHOD(void, output_message, (j_common_ptr cinfo));
      /* Format a message string for the most recent JPEG error or message */
      JMETHOD(void, format_message, (j_common_ptr cinfo, char * buffer));
    #define JMSG_LENGTH_MAX  200	/* recommended size of format_message buffer */
      /* Reset error state variables at start of a new image */
      JMETHOD(void, reset_error_mgr, (j_common_ptr cinfo));

      /* The message ID code and any parameters are saved here.
       * A message can have one string parameter or up to 8 int parameters.
       */
      int msg_code;
    #define JMSG_STR_PARM_MAX  80
      union {
        int i[8];
        char s[JMSG_STR_PARM_MAX];
      } msg_parm;

      /* Standard state variables for error facility */

      int trace_level;		/* max msg_level that will be displayed */

      /* For recoverable corrupt-data errors, we emit a warning message,
       * but keep going unless emit_message chooses to abort.  emit_message
       * should count warnings in num_warnings.  The surrounding application
       * can check for bad data by seeing if num_warnings is nonzero at the
       * end of processing.
       */
      long num_warnings;		/* number of corrupt-data warnings */

      /* These fields point to the table(s) of error message strings.
       * An application can change the table pointer to switch to a different
       * message list (typically, to change the language in which errors are
       * reported).  Some applications may wish to add additional error codes
       * that will be handled by the JPEG library error mechanism; the second
       * table pointer is used for this purpose.
       *
       * First table includes all errors generated by JPEG library itself.
       * Error code 0 is reserved for a "no such error string" message.
       */
      const char * const * jpeg_message_table; /* Library errors */
      int last_jpeg_message;    /* Table contains strings 0..last_jpeg_message */
      /* Second table can be added by application (see cjpeg/djpeg for example).
       * It contains strings numbered first_addon_message..last_addon_message.
       */
      const char * const * addon_message_table; /* Non-library errors */
      int first_addon_message;	/* code for first string in addon table */
      int last_addon_message;	/* code for last string in addon table */
    };

    /* Progress monitor object */

    struct jpeg_progress_mgr {
      JMETHOD(void, progress_monitor, (j_common_ptr cinfo));

      long pass_counter;		/* work units completed in this pass */
      long pass_limit;		/* total number of work units in this pass */
      int completed_passes;		/* passes completed so far */
      int total_passes;		/* total number of passes expected */
    };

    /* Data destination object for compression */

    struct jpeg_destination_mgr {
      JOCTET * next_output_byte;	/* => next byte to write in buffer */
      size_t free_in_buffer;	/* # of byte spaces remaining in buffer */

      JMETHOD(void, init_destination, (j_compress_ptr cinfo));
      JMETHOD(int, empty_output_buffer, (j_compress_ptr cinfo));
      JMETHOD(void, term_destination, (j_compress_ptr cinfo));
    };

    /* Data source object for decompression */

    struct jpeg_source_mgr {
      const JOCTET * next_input_byte; /* => next byte to read from buffer */
      size_t bytes_in_buffer;	/* # of bytes remaining in buffer */

      JMETHOD(void, init_source, (j_decompress_ptr cinfo));
      JMETHOD(int, fill_input_buffer, (j_decompress_ptr cinfo));
      JMETHOD(void, skip_input_data, (j_decompress_ptr cinfo, long num_bytes));
      JMETHOD(int, resync_to_restart, (j_decompress_ptr cinfo, int desired));
      JMETHOD(void, term_source, (j_decompress_ptr cinfo));
    };

    /* Memory manager object.
     * Allocates "small" objects (a few K total), "large" objects (tens of K),
     * and "really big" objects (virtual arrays with backing store if needed).
     * The memory manager does not allow individual objects to be freed; rather,
     * each created object is assigned to a pool, and whole pools can be freed
     * at once.  This is faster and more convenient than remembering exactly what
     * to free, especially where malloc()/free() are not too speedy.
     * NB: alloc routines never return NULL.  They exit to error_exit if not
     * successful.
     */

    #define JPOOL_PERMANENT	0	/* lasts until master record is destroyed */
    #define JPOOL_IMAGE	1	/* lasts until done with image/datastream */
    #define JPOOL_NUMPOOLS	2

    typedef struct jvirt_sarray_control * jvirt_sarray_ptr;
    typedef struct jvirt_barray_control * jvirt_barray_ptr;

    struct jpeg_memory_mgr {
      /* Method pointers */
      JMETHOD(void *, alloc_small, (j_common_ptr cinfo, int pool_id,
    				size_t sizeofobject));
      JMETHOD(void FAR *, alloc_large, (j_common_ptr cinfo, int pool_id,
    				     size_t sizeofobject));
      JMETHOD(JSAMPARRAY, alloc_sarray, (j_common_ptr cinfo, int pool_id,
    				     JDIMENSION samplesperrow,
    				     JDIMENSION numrows));
      JMETHOD(JBLOCKARRAY, alloc_barray, (j_common_ptr cinfo, int pool_id,
    				      JDIMENSION blocksperrow,
    				      JDIMENSION numrows));
      JMETHOD(jvirt_sarray_ptr, request_virt_sarray, (j_common_ptr cinfo,
    						  int pool_id,
    						  int pre_zero,
    						  JDIMENSION samplesperrow,
    						  JDIMENSION numrows,
    						  JDIMENSION maxaccess));
      JMETHOD(jvirt_barray_ptr, request_virt_barray, (j_common_ptr cinfo,
    						  int pool_id,
    						  int pre_zero,
    						  JDIMENSION blocksperrow,
    						  JDIMENSION numrows,
    						  JDIMENSION maxaccess));
      JMETHOD(void, realize_virt_arrays, (j_common_ptr cinfo));
      JMETHOD(JSAMPARRAY, access_virt_sarray, (j_common_ptr cinfo,
    					   jvirt_sarray_ptr ptr,
    					   JDIMENSION start_row,
    					   JDIMENSION num_rows,
    					   int writable));
      JMETHOD(JBLOCKARRAY, access_virt_barray, (j_common_ptr cinfo,
    					    jvirt_barray_ptr ptr,
    					    JDIMENSION start_row,
    					    JDIMENSION num_rows,
    					    int writable));
      JMETHOD(void, free_pool, (j_common_ptr cinfo, int pool_id));
      JMETHOD(void, self_destruct, (j_common_ptr cinfo));

      /* Limit on memory allocation for this JPEG object.  (Note that this is
       * merely advisory, not a guaranteed maximum; it only affects the space
       * used for virtual-array buffers.)  May be changed by outer application
       * after creating the JPEG object.
       */
      long max_memory_to_use;

      /* Maximum allocation request accepted by alloc_large. */
      long max_alloc_chunk;
    };

    /* Routine signature for application-supplied marker processing methods.
     * Need not pass marker code since it is stored in cinfo->unread_marker.
     */
    typedef JMETHOD(int, jpeg_marker_parser_method, (j_decompress_ptr cinfo));

    /* Declarations for routines called by application.
     * The JPP macro hides prototype parameters from compilers that can't cope.
     * Note JPP requires double parentheses.
     */

    #ifdef HAVE_PROTOTYPES
    #define JPP(arglist)	arglist
    #else
    #define JPP(arglist)	()
    #endif

    /* Short forms of external names for systems with brain-damaged linkers.
     * We shorten external names to be unique in the first six letters, which
     * is good enough for all known systems.
     * (If your compiler itself needs names to be unique in less than 15
     * characters, you are out of luck.  Get a better compiler.)
     */

    #ifdef NEED_SHORT_EXTERNAL_NAMES
    #define jpeg_std_error		jStdError
    #define jpeg_CreateCompress	jCreaCompress
    #define jpeg_CreateDecompress	jCreaDecompress
    #define jpeg_destroy_compress	jDestCompress
    #define jpeg_destroy_decompress	jDestDecompress
    #define jpeg_stdio_dest		jStdDest
    #define jpeg_stdio_src		jStdSrc
    #define jpeg_set_defaults	jSetDefaults
    #define jpeg_set_colorspace	jSetColorspace
    #define jpeg_default_colorspace	jDefColorspace
    #define jpeg_set_quality	jSetQuality
    #define jpeg_set_linear_quality	jSetLQuality
    #define jpeg_add_quant_table	jAddQuantTable
    #define jpeg_quality_scaling	jQualityScaling
    #define jpeg_simple_progression	jSimProgress
    #define jpeg_suppress_tables	jSuppressTables
    #define jpeg_alloc_quant_table	jAlcQTable
    #define jpeg_alloc_huff_table	jAlcHTable
    #define jpeg_start_compress	jStrtCompress
    #define jpeg_write_scanlines	jWrtScanlines
    #define jpeg_finish_compress	jFinCompress
    #define jpeg_write_raw_data	jWrtRawData
    #define jpeg_write_marker	jWrtMarker
    #define jpeg_write_m_header	jWrtMHeader
    #define jpeg_write_m_byte	jWrtMByte
    #define jpeg_write_tables	jWrtTables
    #define jpeg_read_header	jReadHeader
    #define jpeg_start_decompress	jStrtDecompress
    #define jpeg_read_scanlines	jReadScanlines
    #define jpeg_finish_decompress	jFinDecompress
    #define jpeg_read_raw_data	jReadRawData
    #define jpeg_has_multiple_scans	jHasMultScn
    #define jpeg_start_output	jStrtOutput
    #define jpeg_finish_output	jFinOutput
    #define jpeg_input_complete	jInComplete
    #define jpeg_new_colormap	jNewCMap
    #define jpeg_consume_input	jConsumeInput
    #define jpeg_calc_output_dimensions	jCalcDimensions
    #define jpeg_save_markers	jSaveMarkers
    #define jpeg_set_marker_processor	jSetMarker
    #define jpeg_read_coefficients	jReadCoefs
    #define jpeg_write_coefficients	jWrtCoefs
    #define jpeg_copy_critical_parameters	jCopyCrit
    #define jpeg_abort_compress	jAbrtCompress
    #define jpeg_abort_decompress	jAbrtDecompress
    #define jpeg_abort		jAbort
    #define jpeg_destroy		jDestroy
    #define jpeg_resync_to_restart	jResyncRestart
    #endif /* NEED_SHORT_EXTERNAL_NAMES */

    /* Default error-management setup */
    EXTERN(struct jpeg_error_mgr *) jpeg_std_error
    	JPP((struct jpeg_error_mgr * err));

    /* Initialization of JPEG compression objects.
     * jpeg_create_compress() and jpeg_create_decompress() are the exported
     * names that applications should call.  These expand to calls on
     * jpeg_CreateCompress and jpeg_CreateDecompress with additional information
     * passed for version mismatch checking.
     * NB: you must set up the error-manager BEFORE calling jpeg_create_xxx.
     */
    #define jpeg_create_compress(cinfo) \
        jpeg_CreateCompress((cinfo), JPEG_LIB_VERSION, \
    			(size_t) sizeof(struct jpeg_compress_struct))
    #define jpeg_create_decompress(cinfo) \
        jpeg_CreateDecompress((cinfo), JPEG_LIB_VERSION, \
    			  (size_t) sizeof(struct jpeg_decompress_struct))
    EXTERN(void) jpeg_CreateCompress JPP((j_compress_ptr cinfo,
    				      int version, size_t structsize));
    EXTERN(void) jpeg_CreateDecompress JPP((j_decompress_ptr cinfo,
    					int version, size_t structsize));
    /* Destruction of JPEG compression objects */
    EXTERN(void) jpeg_destroy_compress JPP((j_compress_ptr cinfo));
    EXTERN(void) jpeg_destroy_decompress JPP((j_decompress_ptr cinfo));

    /* Standard data source and destination managers: stdio streams. */
    /* Caller is responsible for opening the file before and closing after. */
    EXTERN(void) jpeg_stdio_dest JPP((j_compress_ptr cinfo, FILE * outfile));
    EXTERN(void) jpeg_stdio_src JPP((j_decompress_ptr cinfo, FILE * infile));

    /* Default parameter setup for compression */
    EXTERN(void) jpeg_set_defaults JPP((j_compress_ptr cinfo));
    /* Compression parameter setup aids */
    EXTERN(void) jpeg_set_colorspace JPP((j_compress_ptr cinfo,
    				      J_COLOR_SPACE colorspace));
    EXTERN(void) jpeg_default_colorspace JPP((j_compress_ptr cinfo));
    EXTERN(void) jpeg_set_quality JPP((j_compress_ptr cinfo, int quality,
    				   int force_baseline));
    EXTERN(void) jpeg_set_linear_quality JPP((j_compress_ptr cinfo,
    					  int scale_factor,
    					  int force_baseline));
    EXTERN(void) jpeg_add_quant_table JPP((j_compress_ptr cinfo, int which_tbl,
    				       const unsigned int *basic_table,
    				       int scale_factor,
    				       int force_baseline));
    EXTERN(int) jpeg_quality_scaling JPP((int quality));
    EXTERN(void) jpeg_simple_progression JPP((j_compress_ptr cinfo));
    EXTERN(void) jpeg_suppress_tables JPP((j_compress_ptr cinfo,
    				       int suppress));
    EXTERN(JQUANT_TBL *) jpeg_alloc_quant_table JPP((j_common_ptr cinfo));
    EXTERN(JHUFF_TBL *) jpeg_alloc_huff_table JPP((j_common_ptr cinfo));

    /* Main entry points for compression */
    EXTERN(void) jpeg_start_compress JPP((j_compress_ptr cinfo,
    				      int write_all_tables));
    EXTERN(JDIMENSION) jpeg_write_scanlines JPP((j_compress_ptr cinfo,
    					     JSAMPARRAY scanlines,
    					     JDIMENSION num_lines));
    EXTERN(void) jpeg_finish_compress JPP((j_compress_ptr cinfo));

    /* Replaces jpeg_write_scanlines when writing raw downsampled data. */
    EXTERN(JDIMENSION) jpeg_write_raw_data JPP((j_compress_ptr cinfo,
    					    JSAMPIMAGE data,
    					    JDIMENSION num_lines));

    /* Write a special marker.  See libjpeg.doc concerning safe usage. */
    EXTERN(void) jpeg_write_marker
    	JPP((j_compress_ptr cinfo, int marker,
    	     const JOCTET * dataptr, unsigned int datalen));
    /* Same, but piecemeal. */
    EXTERN(void) jpeg_write_m_header
    	JPP((j_compress_ptr cinfo, int marker, unsigned int datalen));
    EXTERN(void) jpeg_write_m_byte
    	JPP((j_compress_ptr cinfo, int val));

    /* Alternate compression function: just write an abbreviated table file */
    EXTERN(void) jpeg_write_tables JPP((j_compress_ptr cinfo));

    /* Decompression startup: read start of JPEG datastream to see what's there */
    EXTERN(int) jpeg_read_header JPP((j_decompress_ptr cinfo,
    				  int require_image));
    /* Return value is one of: */
    #define JPEG_SUSPENDED		0 /* Suspended due to lack of input data */
    #define JPEG_HEADER_OK		1 /* Found valid image datastream */
    #define JPEG_HEADER_TABLES_ONLY	2 /* Found valid table-specs-only datastream */
    /* If you pass require_image = TRUE (normal case), you need not check for
     * a TABLES_ONLY return code; an abbreviated file will cause an error exit.
     * JPEG_SUSPENDED is only possible if you use a data source module that can
     * give a suspension return (the stdio source module doesn't).
     */

    /* Main entry points for decompression */
    EXTERN(int) jpeg_start_decompress JPP((j_decompress_ptr cinfo));
    EXTERN(JDIMENSION) jpeg_read_scanlines JPP((j_decompress_ptr cinfo,
    					    JSAMPARRAY scanlines,
    					    JDIMENSION max_lines));
    EXTERN(int) jpeg_finish_decompress JPP((j_decompress_ptr cinfo));

    /* Replaces jpeg_read_scanlines when reading raw downsampled data. */
    EXTERN(JDIMENSION) jpeg_read_raw_data JPP((j_decompress_ptr cinfo,
    					   JSAMPIMAGE data,
    					   JDIMENSION max_lines));

    /* Additional entry points for buffered-image mode. */
    EXTERN(int) jpeg_has_multiple_scans JPP((j_decompress_ptr cinfo));
    EXTERN(int) jpeg_start_output JPP((j_decompress_ptr cinfo,
    				       int scan_number));
    EXTERN(int) jpeg_finish_output JPP((j_decompress_ptr cinfo));
    EXTERN(int) jpeg_input_complete JPP((j_decompress_ptr cinfo));
    EXTERN(void) jpeg_new_colormap JPP((j_decompress_ptr cinfo));
    EXTERN(int) jpeg_consume_input JPP((j_decompress_ptr cinfo));
    /* Return value is one of: */
    /* #define JPEG_SUSPENDED	0    Suspended due to lack of input data */
    #define JPEG_REACHED_SOS	1 /* Reached start of new scan */
    #define JPEG_REACHED_EOI	2 /* Reached end of image */
    #define JPEG_ROW_COMPLETED	3 /* Completed one iMCU row */
    #define JPEG_SCAN_COMPLETED	4 /* Completed last iMCU row of a scan */

    /* Precalculate output dimensions for current decompression parameters. */
    EXTERN(void) jpeg_calc_output_dimensions JPP((j_decompress_ptr cinfo));

    /* Control saving of COM and APPn markers into marker_list. */
    EXTERN(void) jpeg_save_markers
    	JPP((j_decompress_ptr cinfo, int marker_code,
    	     unsigned int length_limit));

    /* Install a special processing method for COM or APPn markers. */
    EXTERN(void) jpeg_set_marker_processor
    	JPP((j_decompress_ptr cinfo, int marker_code,
    	     jpeg_marker_parser_method routine));

    /* Read or write raw DCT coefficients --- useful for lossless transcoding. */
    EXTERN(jvirt_barray_ptr *) jpeg_read_coefficients JPP((j_decompress_ptr cinfo));
    EXTERN(void) jpeg_write_coefficients JPP((j_compress_ptr cinfo,
    					  jvirt_barray_ptr * coef_arrays));
    EXTERN(void) jpeg_copy_critical_parameters JPP((j_decompress_ptr srcinfo,
    						j_compress_ptr dstinfo));

    /* If you choose to abort compression or decompression before completing
     * jpeg_finish_(de)compress, then you need to clean up to release memory,
     * temporary files, etc.  You can just call jpeg_destroy_(de)compress
     * if you're done with the JPEG object, but if you want to clean it up and
     * reuse it, call this:
     */
    EXTERN(void) jpeg_abort_compress JPP((j_compress_ptr cinfo));
    EXTERN(void) jpeg_abort_decompress JPP((j_decompress_ptr cinfo));

    /* Generic versions of jpeg_abort and jpeg_destroy that work on either
     * flavor of JPEG object.  These may be more convenient in some places.
     */
    EXTERN(void) jpeg_abort JPP((j_common_ptr cinfo));
    EXTERN(void) jpeg_destroy JPP((j_common_ptr cinfo));

    /* Default restart-marker-resync procedure for use by data source modules */
    EXTERN(int) jpeg_resync_to_restart JPP((j_decompress_ptr cinfo,
    					    int desired));

    /* These marker codes are exported since applications and data source modules
     * are likely to want to use them.
     */

    #define JPEG_RST0	0xD0	/* RST0 marker code */
    #define JPEG_EOI	0xD9	/* EOI marker code */
    #define JPEG_APP0	0xE0	/* APP0 marker code */
    #define JPEG_COM	0xFE	/* COM marker code */

    /* If we have a brain-damaged compiler that emits warnings (or worse, errors)
     * for structure definitions that are never filled in, keep it quiet by
     * supplying dummy definitions for the various substructures.
     */

    #ifdef INCOMPLETE_TYPES_BROKEN
    #ifndef JPEG_INTERNALS		/* will be defined in jpegint.h */
    struct jvirt_sarray_control { long dummy; };
    struct jvirt_barray_control { long dummy; };
    struct jpeg_comp_master { long dummy; };
    struct jpeg_c_main_controller { long dummy; };
    struct jpeg_c_prep_controller { long dummy; };
    struct jpeg_c_coef_controller { long dummy; };
    struct jpeg_marker_writer { long dummy; };
    struct jpeg_color_converter { long dummy; };
    struct jpeg_downsampler { long dummy; };
    struct jpeg_forward_dct { long dummy; };
    struct jpeg_entropy_encoder { long dummy; };
    struct jpeg_decomp_master { long dummy; };
    struct jpeg_d_main_controller { long dummy; };
    struct jpeg_d_coef_controller { long dummy; };
    struct jpeg_d_post_controller { long dummy; };
    struct jpeg_input_controller { long dummy; };
    struct jpeg_marker_reader { long dummy; };
    struct jpeg_entropy_decoder { long dummy; };
    struct jpeg_inverse_dct { long dummy; };
    struct jpeg_upsampler { long dummy; };
    struct jpeg_color_deconverter { long dummy; };
    struct jpeg_color_quantizer { long dummy; };
    #endif /* JPEG_INTERNALS */
    #endif /* INCOMPLETE_TYPES_BROKEN */

    /*
     * The JPEG library modules define JPEG_INTERNALS before including this file.
     * The internal structure declarations are read only when that is true.
     * Applications using the library should not include jpegint.h, but may wish
     * to include jerror.h.
     */

    #ifdef JPEG_INTERNALS
    #include "jpegint.h"		/* fetch private declarations */
    #include "jerror.h"		/* fetch error codes too */
    #endif

    #endif /* JPEGLIB_H */