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Diffstat (limited to 'jcarith.c')
| -rw-r--r-- | jcarith.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/jcarith.c b/jcarith.c new file mode 100644 index 0000000..1949459 --- /dev/null +++ b/jcarith.c @@ -0,0 +1,42 @@ +/* + * 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 */ |