mirror of
https://github.com/opencv/opencv.git
synced 2024-12-13 07:59:27 +08:00
48 lines
1.5 KiB
C
48 lines
1.5 KiB
C
|
/*
|
||
|
|
* 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, boolean 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[]));
|