blob: 314a2325c9e55b9958dedea9d101b3dc2af221ef (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
|
/*
* 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[]);
|
