hcomp.h

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/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
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 * terms governing use, modification, and redistribution, is contained in    *
 * the files COPYING and Copyright.html.  COPYING can be found at the root   *
 * of the source code distribution tree; Copyright.html can be found at      *
 * http://hdfgroup.org/products/hdf4/doc/Copyright.html.  If you do not have *
 * access to either file, you may request a copy from help@hdfgroup.org.     *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/* $Id: hcomp.h 4932 2007-09-07 17:17:23Z bmribler $ */

/*-----------------------------------------------------------------------------
 * File:    hcomp.h
 * Purpose: header file for compression information & structures
 * Dependencies: should be included after hdf.h
 * Invokes:
 * Contents:
 * Structure definitions: comp_info
 * Constant definitions: lots...
 *---------------------------------------------------------------------------*/

/* avoid re-inclusion */
#ifndef __HCOMP_H
#define __HCOMP_H

/* For determining which type of modeling is being done */
typedef enum
  {
      COMP_MODEL_STDIO = 0      /* for Standard C I/O model */
  }
comp_model_t;

/* For determining which type of encoding is being done */
typedef enum
  {
      COMP_CODE_NONE = 0,       /* don't encode at all, just store */
      COMP_CODE_RLE,            /* for simple RLE encoding */
      COMP_CODE_NBIT,           /* for N-bit encoding */
      COMP_CODE_SKPHUFF,        /* for Skipping huffman encoding */
      COMP_CODE_DEFLATE,        /* for gzip 'deflate' encoding */
      COMP_CODE_SZIP,       /* for szip encoding */
      COMP_CODE_INVALID,        /* invalid last code, for range checking */
      COMP_CODE_JPEG            /* _Ugly_ hack to allow JPEG images to be created with GRsetcompress */
  }
comp_coder_t;

/* Compression types available */
#define COMP_NONE       0
#define COMP_JPEG       2
#define COMP_RLE        11
#define COMP_IMCOMP     12

/* Compression encoder/decoder configuration */
#define COMP_DECODER_ENABLED     1
#define COMP_ENCODER_ENABLED     2

#ifndef COMPRESS_MASTER
extern uint16 compress_map[];
#else
uint16      compress_map[COMP_MAX_COMP + 1] =
{                               /* Mapping from compression types to tags */
    0,                          /* No corresponding tag for un-compressed data */
    0,                          /* (1) */
    DFTAG_JPEG5,                /* COMP_JPEG -> DFTAG_JPEG5 (for JPEG compression) */
    0,                          /* (3) */
    0,                          /* (4) */
    0,                          /* (5) */
    0,                          /* (6) */
    0,                          /* (7) */
    0,                          /* (8) */
    0,                          /* (9) */
    0,                          /* (10) */
    DFTAG_RLE,                  /* COMP_RLE -> DFTAG_RLE (for Run-length compression) */
    DFTAG_IMC                   /* COMP_IMCOMP -> DFTAG_IMC (for IMCOMP compression) */
};
#endif

typedef union tag_model_info
  {                             /* Union to contain modeling information */
      struct
        {
            int32       nt;     /* number type */
            intn        ndim;   /* number of dimensions */
            int32      *dims;   /* array of dimensions */
        }
      dim;
  }
model_info;

typedef union tag_comp_info
  {                             /* Union to contain compression information */
      struct
        {   /* Struct to contain information about how to compress */
            /* or decompress a JPEG encoded 24-bit image */
            intn    quality;    /* Quality factor for JPEG compression, should be from */
            /* 0 (terrible) to 100 (very good) */
            intn    force_baseline;     /* If force_baseline is set to TRUE then */
            /* quantization tables are limited to */
            /* 0..255 for JPEG baseline compability */
            /* This is only an issue for quality */
            /* settings below 24 */
        }
      jpeg;
      struct
        {   /* struct to contain information about how to compress */
            /* or decompress a N-bit encoded dataset */
            int32   nt;     /* number type of the data to encode */
            intn    sign_ext;   /* whether to sign extend or not */
            intn    fill_one;   /* whether to fill with 1's or 0's */
            intn    start_bit;  /* offset of the start bit in the data */
            intn    bit_len;    /* number of bits to store */
        }
      nbit;
      struct
        {   /* struct to contain info about how to compress */
            /* or decompress a "skipping" huffman encoded dataset */
            intn    skp_size;   /* size of the individual elements when skipping */
        }
      skphuff;
      struct
        {   /* struct to contain info about how to compress */
            /* or decompress a gzip encoded dataset */
            intn    level;   /* how hard to work when compressing the data */
        }
      deflate;
      struct
        {
            int32 options_mask;   /* IN */
            int32 pixels_per_block;   /* IN */
            int32 pixels_per_scanline; /* OUT: computed */
        int32 bits_per_pixel; /* OUT: size of NT */
            int32 pixels; /* OUT: size of dataset or chunk */
         }
       szip;  /* for szip encoding */

  }
comp_info;

#endif /* __HCOMP_H */