/*
 * jchuff.h
 *
 * This file was part of the Independent JPEG Group's software:
 * Copyright (C) 1991-1997, Thomas G. Lane.
 * It was modified by The libjpeg-turbo Project to include only code relevant
 * to libjpeg-turbo.
 * For conditions of distribution and use, see the accompanying README.ijg
 * 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;

/* Expand a Huffman table definition into the derived format */
EXTERN(void)

jpeg_make_c_derived_tbl
(j_compress_ptr
cinfo,
boolean isDC,
int tblno,
		c_derived_tbl
** pdtbl);

/* Generate an optimal table definition given the specified counts */
EXTERN(void)

jpeg_gen_optimal_table
(j_compress_ptr
cinfo,
JHUFF_TBL *htbl,
long freq[]
);
