    /*
     * jchuff.h
     *
     * Copyright (C) 1991-1997, 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 contains declarations for Huffman entropy encoding routines
     * that are shared between the sequential encoder (jchuff.c) and the
     * progressive encoder (jcphuff.c).  No other modules need to see these.
     */

    /* The legal range of a DCT coefficient is
     *  -1024 .. +1023  for 8-bit data;
     * -16384 .. +16383 for 12-bit data.
     * Hence the magnitude should always fit in 10 or 14 bits respectively.
     */

    #if BITS_IN_JSAMPLE == 8
    #define MAX_COEF_BITS 10
    #else
    #define MAX_COEF_BITS 14
    #endif

    /* Derived data constructed for each Huffman table */

    typedef struct {
      unsigned int ehufco[256];	/* code for each symbol */
      char ehufsi[256];		/* length of code for each symbol */
      /* If no code has been allocated for a symbol S, ehufsi[S] contains 0 */
    } c_derived_tbl;

    /* Short forms of external names for systems with brain-damaged linkers. */

    #ifdef NEED_SHORT_EXTERNAL_NAMES
    #define jpeg_make_c_derived_tbl	jMkCDerived
    #define jpeg_gen_optimal_table	jGenOptTbl
    #endif /* NEED_SHORT_EXTERNAL_NAMES */

    /* Expand a Huffman table definition into the derived format */
    EXTERN(void) jpeg_make_c_derived_tbl
    	JPP((j_compress_ptr cinfo, int isDC, int tblno,
    	     c_derived_tbl ** pdtbl));

    /* Generate an optimal table definition given the specified counts */
    EXTERN(void) jpeg_gen_optimal_table
    	JPP((j_compress_ptr cinfo, JHUFF_TBL * htbl, long freq[]));