43 lines
1.1 KiB
C
43 lines
1.1 KiB
C
|
/*
|
||
|
|
* jcarith.c
|
||
|
|
*
|
||
|
|
* Copyright (C) 1991, 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 arithmetic entropy encoding routines.
|
||
|
|
* These routines are invoked via the methods entropy_encode,
|
||
|
|
* entropy_encoder_init/term, and entropy_optimize.
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "jinclude.h"
|
||
|
|
|
||
|
|
#ifdef ARITH_CODING_SUPPORTED
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The arithmetic coding option of the JPEG standard specifies Q-coding,
|
||
|
|
* which is covered by patents held by IBM (and possibly AT&T and Mitsubishi).
|
||
|
|
* At this time it does not appear to be legal for the Independent JPEG
|
||
|
|
* Group to distribute software that implements arithmetic coding.
|
||
|
|
* We have therefore removed arithmetic coding support from the
|
||
|
|
* distributed source code.
|
||
|
|
*
|
||
|
|
* We're not happy about it either.
|
||
|
|
*/
|
||
|
|
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The method selection routine for arithmetic entropy encoding.
|
||
|
|
*/
|
||
|
|
|
||
|
|
GLOBAL void
|
||
|
|
jselcarithmetic (compress_info_ptr cinfo)
|
||
|
|
{
|
||
|
|
if (cinfo->arith_code) {
|
||
|
|
ERREXIT(cinfo->emethods, "Sorry, there are legal restrictions on arithmetic coding");
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* ARITH_CODING_SUPPORTED */
|