113 lines
4.2 KiB
C
113 lines
4.2 KiB
C
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
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* Copyright by The HDF Group. *
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* Copyright by the Board of Trustees of the University of Illinois. *
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* All rights reserved. *
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* *
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* This file is part of HDF. The full HDF copyright notice, including *
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* terms governing use, modification, and redistribution, is contained in *
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* the COPYING file, which can be found at the root of the source code *
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* distribution tree, or in https://support.hdfgroup.org/ftp/HDF/releases/. *
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* If you do not have access to either file, you may request a copy from *
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* help@hdfgroup.org. *
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* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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/* $Id$ */
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/*-----------------------------------------------------------------------------
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* File: cnbit.h
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* Purpose: Header file for N-bit encoding information.
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* Dependencies: should only be included from hcompi.h
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* Invokes: none
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* Contents: Structures & definitions for N-bit encoding.
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* Structure definitions:
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* Constant definitions:
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*---------------------------------------------------------------------------*/
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/* avoid re-inclusion */
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#ifndef __CNBIT_H
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#define __CNBIT_H
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#if defined c_plusplus || defined __cplusplus
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extern "C"
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{
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#endif /* c_plusplus || __cplusplus */
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/*
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** from cnbit.c
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*/
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HDFLIBAPI int32 HCPcnbit_stread
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(accrec_t * rec);
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HDFLIBAPI int32 HCPcnbit_stwrite
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(accrec_t * rec);
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HDFLIBAPI int32 HCPcnbit_seek
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(accrec_t * access_rec, int32 offset, int origin);
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HDFLIBAPI int32 HCPcnbit_inquire
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(accrec_t * access_rec, int32 *pfile_id, uint16 *ptag, uint16 *pref,
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int32 *plength, int32 *poffset, int32 *pposn, int16 *paccess,
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int16 *pspecial);
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HDFLIBAPI int32 HCPcnbit_read
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(accrec_t * access_rec, int32 length, void * data);
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HDFLIBAPI int32 HCPcnbit_write
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(accrec_t * access_rec, int32 length, const void * data);
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HDFLIBAPI intn HCPcnbit_endaccess
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(accrec_t * access_rec);
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#if defined c_plusplus || defined __cplusplus
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}
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#endif /* c_plusplus || __cplusplus */
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/* size of the N-bit buffer */
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#define NBIT_BUF_SIZE (MAX_NT_SIZE*64)
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/* size of the N-bit mask buffer (same as buffer size for now) */
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#define NBIT_MASK_SIZE (MAX_NT_SIZE)
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typedef struct
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{ /* structure to hold bit vector info */
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intn offset, /* offset of the bit information */
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length; /* number of bits in the information */
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uint8 mask; /* mask for this bit vector */
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}
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nbit_mask_info_t;
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/* N-bit [en|de]coding information */
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typedef struct
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{
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int32 nt; /* number type of data we are encoding */
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intn nt_size; /* size of the number-type in the file */
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intn fill_one; /* whether to fill with 1's or not (0's) */
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intn sign_ext; /* whether to sign extend or not */
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uint8 buffer[NBIT_BUF_SIZE]; /* buffer for expanding n-bit data in */
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intn buf_pos; /* current offset in the expansion buffer */
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intn mask_off, /* offset of the bit to start masking with */
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mask_len; /* number of bits to mask */
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int32 offset; /* offset in the file in terms of bytes */
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uint8 mask_buf[NBIT_MASK_SIZE]; /* buffer to hold the bitmask */
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nbit_mask_info_t mask_info[NBIT_MASK_SIZE]; /* information about the mask */
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intn nt_pos; /* current byte to read or write */
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}
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comp_coder_nbit_info_t;
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#ifndef CNBIT_MASTER
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extern funclist_t cnbit_funcs; /* functions to perform N-bit encoding */
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#else
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funclist_t cnbit_funcs =
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{ /* functions to perform N-bit encoding */
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HCPcnbit_stread,
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HCPcnbit_stwrite,
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HCPcnbit_seek,
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HCPcnbit_inquire,
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HCPcnbit_read,
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HCPcnbit_write,
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HCPcnbit_endaccess
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};
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#endif
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#endif /* __CNBIT_H */
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