/* * jdarith.c * * Copyright (C) 1991, 1992, 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 decoding routines. * These routines are invoked via the methods entropy_decode * and entropy_decode_init/term. */ #include "jinclude.h" #ifdef D_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 decoding. */ GLOBAL void jseldarithmetic (decompress_info_ptr cinfo) { if (cinfo->arith_code) { ERREXIT(cinfo->emethods, "Sorry, there are legal restrictions on arithmetic coding"); } } #endif /* D_ARITH_CODING_SUPPORTED */