--- /dev/null
+From 195345e454d3df7ff9c07c3d36881ec52e789af2 Mon Sep 17 00:00:00 2001
+From: Mukund Sivaraman <muks@banu.com>
+Date: Sun, 3 Oct 2010 12:23:41 +0530
+Subject: [PATCH] Add support for decoding arithmetic coded content
+
+This is based on a patch by Guido Vollbeding <guivol@esc.de>, which
+included code to both encode and decode arithmetic coded content.
+
+This patch only adds the decoding portion. No new arithmetic coded
+content can be produced, but existing arithmetic coded content can
+be decoded.
+
+libjpeg-turbo with this patch has been tested with some arithmetic
+coded images (digital photographs).
+---
+ Makefile.am | 17 +-
+ README.arithmetic | 215 +++++++++++++++
+ jaricom.c | 149 +++++++++++
+ jdarith.c | 762 +++++++++++++++++++++++++++++++++++++++++++++++++++++
+ jdmaster.c | 2 +-
+ jdtrans.c | 2 +-
+ jerror.h | 2 +
+ jmorecfg.h | 2 +-
+ jpegint.h | 2 +
+ 9 files changed, 1142 insertions(+), 11 deletions(-)
+ create mode 100644 README.arithmetic
+ create mode 100644 jaricom.c
+ create mode 100644 jdarith.c
+
+diff --git a/Makefile.am b/Makefile.am
+index f8552ea..1eee598 100644
+--- a/Makefile.am
++++ b/Makefile.am
+@@ -7,14 +7,15 @@ nodist_include_HEADERS = jconfig.h
+ HDRS = jchuff.h jdct.h jdhuff.h jerror.h jinclude.h jmemsys.h jmorecfg.h \
+ jpegint.h jpeglib.h jversion.h jsimd.h jsimddct.h
+
+-libjpeg_la_SOURCES = $(HDRS) jcapimin.c jcapistd.c jccoefct.c jccolor.c \
+- jcdctmgr.c jchuff.c jcinit.c jcmainct.c jcmarker.c jcmaster.c \
+- jcomapi.c jcparam.c jcphuff.c jcprepct.c jcsample.c jctrans.c \
+- jdapimin.c jdapistd.c jdatadst.c jdatasrc.c jdcoefct.c jdcolor.c \
+- jddctmgr.c jdhuff.c jdinput.c jdmainct.c jdmarker.c jdmaster.c \
+- jdmerge.c jdphuff.c jdpostct.c jdsample.c jdtrans.c jerror.c \
+- jfdctflt.c jfdctfst.c jfdctint.c jidctflt.c jidctfst.c jidctint.c \
+- jidctred.c jquant1.c jquant2.c jutils.c jmemmgr.c jmemnobs.c
++libjpeg_la_SOURCES = $(HDRS) jaricom.c jcapimin.c jcapistd.c \
++ jccoefct.c jccolor.c jcdctmgr.c jchuff.c jcinit.c jcmainct.c \
++ jcmarker.c jcmaster.c jcomapi.c jcparam.c jcphuff.c jcprepct.c \
++ jcsample.c jctrans.c jdapimin.c jdapistd.c jdarith.c \
++ jdatadst.c jdatasrc.c jdcoefct.c jdcolor.c jddctmgr.c jdhuff.c \
++ jdinput.c jdmainct.c jdmarker.c jdmaster.c jdmerge.c jdphuff.c \
++ jdpostct.c jdsample.c jdtrans.c jerror.c jfdctflt.c jfdctfst.c \
++ jfdctint.c jidctflt.c jidctfst.c jidctint.c jidctred.c \
++ jquant1.c jquant2.c jutils.c jmemmgr.c jmemnobs.c
+
+ libturbojpeg_la_SOURCES = $(libjpeg_la_SOURCES) turbojpegl.c turbojpeg.h \
+ turbojpeg-mapfile
+diff --git a/README.arithmetic b/README.arithmetic
+new file mode 100644
+index 0000000..0dd3b9a
+--- /dev/null
++++ b/README.arithmetic
+@@ -0,0 +1,215 @@
++JPEG arithmetic encoding and decoding portable software implementation
++======================================================================
++
++Release of 28-Mar-98 by Guido Vollbeding <guido@jpegclub.org>
++=============================================================
++
++Primary URLs:
++
++ http://sylvana.net/jpeg-ari/
++ (directory containing the actual archive files:)
++
++ http://sylvana.net/jpeg-ari/jpeg-ari-28mar98.tar.gz
++
++ http://sylvana.net/jpeg-ari/jpeg-ari.zip
++
++
++DISCLAIMER
++==========
++
++This package is distributed in the hope that it will be useful,
++but WITHOUT ANY WARRANTY; without even the implied warranty of
++MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
++
++It is possible that certain products which can be built using this
++software modules might form inventions protected by patent rights in
++some countries (e.g. by patents about arithmetic coding algorithms
++owned by IBM and AT&T in the USA). Provision of this software by the
++author does NOT include any licenses for any patents.
++In those countries where a patent license is required for certain
++applications of this software modules, you will have to obtain such
++a license yourself.
++
++See Annex L in the JPEG spec for further information
++and a list of relevant patents.
++
++
++What is it?
++===========
++
++This is my implementation of the arithmetic encoding and decoding
++back-end for JPEG as specified in the
++
++ ISO/IEC International Standard 10918-1 and CCITT Recommendation
++ ITU-T T.81, "Information Technology - Digital Compression and
++ Coding of Continuous-tone Still Images, Part 1: Requirements
++ and Guidelines".
++
++Arithmetic coding is a state-of-the-art lossless entropy data
++compression method which offers better compression performance
++than the well-established Huffman entropy coding process.
++
++The JPEG standard specifies a particular arithmetic coding scheme
++to be used optionally as alternative to Huffman coding.
++
++
++Who needs it?
++=============
++
++This package might be of interest for people who are looking for
++enhanced state-of-the-art image compression technologies.
++
++It is intended to provide a reasonable tool for experimental,
++comparison and evaluation purposes.
++
++See the Disclaimer above for restricted conditions of usage.
++
++
++How does it work?
++=================
++
++This distribution is organized as add-on to the widespread
++Independent JPEG Group's JPEG software.
++
++Thus, once you managed to install the IJG software distribution
++successfully, there should be no additional problems (portability
++issues etc.) to incorporate this package into the library,
++and usage is straightforward.
++
++Transcode given JPEG files simply with a command like
++
++ jpegtran -arithmetic [-progressive] < orig.jpg > arit.jpg
++
++into an arithmetic coded version LOSSLESSLY! Since there are
++practically no applications in existence which can handle such
++files, you can only transform it back with the same tool
++
++ jpegtran [-optimize] [-progressive] < arit.jpg > orig2.jpg
++
++to verify correct operation.
++
++Thus, you can easily verify the enhanced compression performance
++of the arithmetic coding version compared to the Huffman (with
++fixed or custom tables) version.
++
++The claim to evaluate was that arithmetic coding gives an average
++5-10% compression improvement against Huffman.
++Early tests with this implementation support this claim, and you
++can perform tests with own material.
++
++Here are some actual results:
++
++% ./jpegtran -optimize < testorig.jpg > testopt.jpg
++% ./jpegtran -arithmetic < testorig.jpg > testarit.jpg
++% ./jpegtran < testarit.jpg > testorig2.jpg
++% ./jpegtran -arithmetic -progressive < testorig.jpg > testaritp.jpg
++% ./jpegtran < testaritp.jpg > testorig3.jpg
++% ./jpegtran -optimize < ../butterfly.jpg > ../buttopt.jpg
++% ./jpegtran -progressive < ../butterfly.jpg > ../buttprog.jpg
++% ./jpegtran -arithmetic < ../butterfly.jpg > ../buttarit.jpg
++% ./jpegtran < ../buttarit.jpg > ../butterfly2.jpg
++% ./jpegtran -arithmetic -progressive < ../butterfly.jpg > ../buttaritp.jpg
++% ./jpegtran < ../buttaritp.jpg > ../butterfly3.jpg
++% ls -l test*.jpg
++-rw-r--r-- 1 guivol 5153 Apr 13 18:51 testarit.jpg
++-rw-r--r-- 1 guivol 5186 Apr 13 18:51 testaritp.jpg
++-rw-r--r-- 1 guivol 5756 Apr 2 15:10 testimg.jpg
++-rw-r--r-- 1 guivol 5645 Apr 2 15:10 testimgp.jpg
++-rw-r--r-- 1 guivol 5463 Apr 13 18:51 testopt.jpg
++-rw-r--r-- 1 guivol 5770 Apr 2 15:10 testorig.jpg
++-rw-r--r-- 1 guivol 5770 Apr 13 18:51 testorig2.jpg
++-rw-r--r-- 1 guivol 5770 Apr 13 18:51 testorig3.jpg
++-rw-r--r-- 1 guivol 5655 Apr 2 15:10 testprog.jpg
++% ls -l ../butt*.jpg
++-rw-r--r-- 1 guivol 460091 Apr 13 18:52 ../buttarit.jpg
++-rw-r--r-- 1 guivol 453703 Apr 13 18:52 ../buttaritp.jpg
++-rw-r--r-- 1 guivol 527823 Nov 19 18:41 ../butterfly.jpg
++-rw-r--r-- 1 guivol 527823 Apr 13 18:52 ../butterfly2.jpg
++-rw-r--r-- 1 guivol 527823 Apr 13 18:52 ../butterfly3.jpg
++-rw-r--r-- 1 guivol 511834 Apr 13 18:52 ../buttopt.jpg
++-rw-r--r-- 1 guivol 492237 Apr 13 18:52 ../buttprog.jpg
++%
++
++Note that arithmetic coding requires only a single processing
++pass due to its fully-adaptive nature, and compared to one-pass
++(fixed tables) Huffman the arithmetic coded version consistently
++achieves 10% compression improvement.
++Compared with two-pass (custom tables) Huffman the improvement
++is 5-10%.
++
++Note that I wasn't able yet to cross-check interoperability of
++the produced files with other implementations.
++Thus, I can't be sure that the files are compliant to the spec,
++but I hope so and the tests support it.
++The encoding and decoding processes should be correct anyway,
++however, in the sense that they are complementary to each other
++and thus retain data integrity.
++
++I would appreciate any indications for compliance or interoperability
++with other implementations from somebody.
++Please let me know if you are able to cross-check something.
++
++
++Installation
++============
++
++The installation is a 2-stage procedure:
++
++1. Preparing the IJG package for potential incorporation
++ of the arithmetic coding feature.
++
++2. Incorporation of the actual arithmetic coding modules
++ and enabling the feature for usage.
++
++The reason for this 2-stage process is the hope to make
++step 1 obsolete in future IJG releases.
++The actual implementation should remain separate IMHO due
++to the different usage conditions.
++
++Step 1:
++
++1.1. Copy all files from the subdirectory 'patchv6b' into
++ the IJG software's v6b source directory.
++ This includes minor patches to some files and 3 extra
++ files which hold place for the actual implementation.
++
++1.2. Update your Makefile/Projectfile for the inclusion of
++ the 3 extra files. This will be done automatically
++ if you use a configure-generated makefile and type
++ './configure' (reconfigure).
++
++1.3. Recompile ('make').
++
++See the file 'PATCHES' in 'patchv6b' for details.
++
++Step 2:
++
++2.1. Replace the 3 placeholder files by the actual implementation
++ modules.
++
++2.2. Enable application support of the new features by #defining
++ C_ARITH_CODING_SUPPORTED and D_ARITH_CODING_SUPPORTED
++ in 'jmorecfg.h'.
++
++2.3. Recompile ('make').
++
++Note that I suggest to add 3 placeholder files to the IJG
++distribution. This would remove the need for system-dependent
++changes (Makefiles) and thus considerably simplify the actual
++installation for systems without a configure-generated makefile.
++
++
++References
++==========
++
++- The Independent JPEG Group's software
++
++- JBIG-KIT lossless image compression library by Markus Kuhn
++
++- William B. Pennebaker, Joan L. Mitchell:
++ "JPEG Still Image Data Compression Standard",
++ Van Nostrand Reinhold, 1993, ISBN 0-442-01272-1.
++
++- jpeg-faq (http://www.faqs.org/faqs/jpeg-faq/)
++
++- compression-faq (http://www.faqs.org/faqs/compression-faq/)
+diff --git a/jaricom.c b/jaricom.c
+new file mode 100644
+index 0000000..e4292b0
+--- /dev/null
++++ b/jaricom.c
+@@ -0,0 +1,149 @@
++/*
++ * jaricom.c
++ *
++ * Copyright (C) 1997, Guido Vollbeding <guivol@esc.de>.
++ * This file is NOT part of the Independent JPEG Group's software
++ * for legal reasons.
++ * See the accompanying README file for conditions of distribution and use.
++ *
++ * This file contains probability estimation tables for common use in
++ * arithmetic entropy encoding and decoding routines.
++ *
++ * This data represents Table D.2 in the JPEG spec (ISO/IEC IS 10918-1
++ * and CCITT Recommendation ITU-T T.81) and Table 24 in the JBIG spec
++ * (ISO/IEC IS 11544 and CCITT Recommendation ITU-T T.82).
++ */
++
++#define JPEG_INTERNALS
++#include "jinclude.h"
++#include "jpeglib.h"
++
++/* The following #define specifies the packing of the four components
++ * into the compact INT32 representation.
++ * Note that this formula must match the actual arithmetic encoder
++ * and decoder implementation. The implementation has to be changed
++ * if this formula is changed.
++ * The current organisation is leaned on Markus Kuhn's JBIG
++ * implementation (jbig_tab.c).
++ */
++
++#define V(a,b,c,d) (((INT32)a << 16) | ((INT32)c << 8) | ((INT32)d << 7) | b)
++
++const INT32 jaritab[113] = {
++/*
++ * Index, Qe_Value, Next_Index_LPS, Next_Index_MPS, Switch_MPS
++ */
++/* 0 */ V( 0x5a1d, 1, 1, 1 ),
++/* 1 */ V( 0x2586, 14, 2, 0 ),
++/* 2 */ V( 0x1114, 16, 3, 0 ),
++/* 3 */ V( 0x080b, 18, 4, 0 ),
++/* 4 */ V( 0x03d8, 20, 5, 0 ),
++/* 5 */ V( 0x01da, 23, 6, 0 ),
++/* 6 */ V( 0x00e5, 25, 7, 0 ),
++/* 7 */ V( 0x006f, 28, 8, 0 ),
++/* 8 */ V( 0x0036, 30, 9, 0 ),
++/* 9 */ V( 0x001a, 33, 10, 0 ),
++/* 10 */ V( 0x000d, 35, 11, 0 ),
++/* 11 */ V( 0x0006, 9, 12, 0 ),
++/* 12 */ V( 0x0003, 10, 13, 0 ),
++/* 13 */ V( 0x0001, 12, 13, 0 ),
++/* 14 */ V( 0x5a7f, 15, 15, 1 ),
++/* 15 */ V( 0x3f25, 36, 16, 0 ),
++/* 16 */ V( 0x2cf2, 38, 17, 0 ),
++/* 17 */ V( 0x207c, 39, 18, 0 ),
++/* 18 */ V( 0x17b9, 40, 19, 0 ),
++/* 19 */ V( 0x1182, 42, 20, 0 ),
++/* 20 */ V( 0x0cef, 43, 21, 0 ),
++/* 21 */ V( 0x09a1, 45, 22, 0 ),
++/* 22 */ V( 0x072f, 46, 23, 0 ),
++/* 23 */ V( 0x055c, 48, 24, 0 ),
++/* 24 */ V( 0x0406, 49, 25, 0 ),
++/* 25 */ V( 0x0303, 51, 26, 0 ),
++/* 26 */ V( 0x0240, 52, 27, 0 ),
++/* 27 */ V( 0x01b1, 54, 28, 0 ),
++/* 28 */ V( 0x0144, 56, 29, 0 ),
++/* 29 */ V( 0x00f5, 57, 30, 0 ),
++/* 30 */ V( 0x00b7, 59, 31, 0 ),
++/* 31 */ V( 0x008a, 60, 32, 0 ),
++/* 32 */ V( 0x0068, 62, 33, 0 ),
++/* 33 */ V( 0x004e, 63, 34, 0 ),
++/* 34 */ V( 0x003b, 32, 35, 0 ),
++/* 35 */ V( 0x002c, 33, 9, 0 ),
++/* 36 */ V( 0x5ae1, 37, 37, 1 ),
++/* 37 */ V( 0x484c, 64, 38, 0 ),
++/* 38 */ V( 0x3a0d, 65, 39, 0 ),
++/* 39 */ V( 0x2ef1, 67, 40, 0 ),
++/* 40 */ V( 0x261f, 68, 41, 0 ),
++/* 41 */ V( 0x1f33, 69, 42, 0 ),
++/* 42 */ V( 0x19a8, 70, 43, 0 ),
++/* 43 */ V( 0x1518, 72, 44, 0 ),
++/* 44 */ V( 0x1177, 73, 45, 0 ),
++/* 45 */ V( 0x0e74, 74, 46, 0 ),
++/* 46 */ V( 0x0bfb, 75, 47, 0 ),
++/* 47 */ V( 0x09f8, 77, 48, 0 ),
++/* 48 */ V( 0x0861, 78, 49, 0 ),
++/* 49 */ V( 0x0706, 79, 50, 0 ),
++/* 50 */ V( 0x05cd, 48, 51, 0 ),
++/* 51 */ V( 0x04de, 50, 52, 0 ),
++/* 52 */ V( 0x040f, 50, 53, 0 ),
++/* 53 */ V( 0x0363, 51, 54, 0 ),
++/* 54 */ V( 0x02d4, 52, 55, 0 ),
++/* 55 */ V( 0x025c, 53, 56, 0 ),
++/* 56 */ V( 0x01f8, 54, 57, 0 ),
++/* 57 */ V( 0x01a4, 55, 58, 0 ),
++/* 58 */ V( 0x0160, 56, 59, 0 ),
++/* 59 */ V( 0x0125, 57, 60, 0 ),
++/* 60 */ V( 0x00f6, 58, 61, 0 ),
++/* 61 */ V( 0x00cb, 59, 62, 0 ),
++/* 62 */ V( 0x00ab, 61, 63, 0 ),
++/* 63 */ V( 0x008f, 61, 32, 0 ),
++/* 64 */ V( 0x5b12, 65, 65, 1 ),
++/* 65 */ V( 0x4d04, 80, 66, 0 ),
++/* 66 */ V( 0x412c, 81, 67, 0 ),
++/* 67 */ V( 0x37d8, 82, 68, 0 ),
++/* 68 */ V( 0x2fe8, 83, 69, 0 ),
++/* 69 */ V( 0x293c, 84, 70, 0 ),
++/* 70 */ V( 0x2379, 86, 71, 0 ),
++/* 71 */ V( 0x1edf, 87, 72, 0 ),
++/* 72 */ V( 0x1aa9, 87, 73, 0 ),
++/* 73 */ V( 0x174e, 72, 74, 0 ),
++/* 74 */ V( 0x1424, 72, 75, 0 ),
++/* 75 */ V( 0x119c, 74, 76, 0 ),
++/* 76 */ V( 0x0f6b, 74, 77, 0 ),
++/* 77 */ V( 0x0d51, 75, 78, 0 ),
++/* 78 */ V( 0x0bb6, 77, 79, 0 ),
++/* 79 */ V( 0x0a40, 77, 48, 0 ),
++/* 80 */ V( 0x5832, 80, 81, 1 ),
++/* 81 */ V( 0x4d1c, 88, 82, 0 ),
++/* 82 */ V( 0x438e, 89, 83, 0 ),
++/* 83 */ V( 0x3bdd, 90, 84, 0 ),
++/* 84 */ V( 0x34ee, 91, 85, 0 ),
++/* 85 */ V( 0x2eae, 92, 86, 0 ),
++/* 86 */ V( 0x299a, 93, 87, 0 ),
++/* 87 */ V( 0x2516, 86, 71, 0 ),
++/* 88 */ V( 0x5570, 88, 89, 1 ),
++/* 89 */ V( 0x4ca9, 95, 90, 0 ),
++/* 90 */ V( 0x44d9, 96, 91, 0 ),
++/* 91 */ V( 0x3e22, 97, 92, 0 ),
++/* 92 */ V( 0x3824, 99, 93, 0 ),
++/* 93 */ V( 0x32b4, 99, 94, 0 ),
++/* 94 */ V( 0x2e17, 93, 86, 0 ),
++/* 95 */ V( 0x56a8, 95, 96, 1 ),
++/* 96 */ V( 0x4f46, 101, 97, 0 ),
++/* 97 */ V( 0x47e5, 102, 98, 0 ),
++/* 98 */ V( 0x41cf, 103, 99, 0 ),
++/* 99 */ V( 0x3c3d, 104, 100, 0 ),
++/* 100 */ V( 0x375e, 99, 93, 0 ),
++/* 101 */ V( 0x5231, 105, 102, 0 ),
++/* 102 */ V( 0x4c0f, 106, 103, 0 ),
++/* 103 */ V( 0x4639, 107, 104, 0 ),
++/* 104 */ V( 0x415e, 103, 99, 0 ),
++/* 105 */ V( 0x5627, 105, 106, 1 ),
++/* 106 */ V( 0x50e7, 108, 107, 0 ),
++/* 107 */ V( 0x4b85, 109, 103, 0 ),
++/* 108 */ V( 0x5597, 110, 109, 0 ),
++/* 109 */ V( 0x504f, 111, 107, 0 ),
++/* 110 */ V( 0x5a10, 110, 111, 1 ),
++/* 111 */ V( 0x5522, 112, 109, 0 ),
++/* 112 */ V( 0x59eb, 112, 111, 1 )
++};
+diff --git a/jdarith.c b/jdarith.c
+new file mode 100644
+index 0000000..1ef513e
+--- /dev/null
++++ b/jdarith.c
+@@ -0,0 +1,762 @@
++/*
++ * jdarith.c
++ *
++ * Copyright (C) 1997, Guido Vollbeding <guivol@esc.de>.
++ * This file is NOT part of the Independent JPEG Group's software
++ * for legal reasons.
++ * See the accompanying README file for conditions of distribution and use.
++ *
++ * This file contains portable arithmetic entropy decoding routines for JPEG
++ * (implementing the ISO/IEC IS 10918-1 and CCITT Recommendation ITU-T T.81).
++ *
++ * Both sequential and progressive modes are supported in this single module.
++ *
++ * Suspension is not currently supported in this module.
++ */
++
++#define JPEG_INTERNALS
++#include "jinclude.h"
++#include "jpeglib.h"
++
++
++/* Expanded entropy decoder object for arithmetic decoding. */
++
++typedef struct {
++ struct jpeg_entropy_decoder pub; /* public fields */
++
++ INT32 c; /* C register, base of coding interval + input bit buffer */
++ INT32 a; /* A register, normalized size of coding interval */
++ int ct; /* bit shift counter, # of bits left in bit buffer part of C */
++ /* init: ct = -16 */
++ /* run: ct = 0..7 */
++ /* error: ct = -1 */
++ int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */
++ int dc_context[MAX_COMPS_IN_SCAN]; /* context index for DC conditioning */
++
++ unsigned int restarts_to_go; /* MCUs left in this restart interval */
++
++ /* Pointers to statistics areas (these workspaces have image lifespan) */
++ unsigned char * dc_stats[NUM_ARITH_TBLS];
++ unsigned char * ac_stats[NUM_ARITH_TBLS];
++} arith_entropy_decoder;
++
++typedef arith_entropy_decoder * arith_entropy_ptr;
++
++/* The following two definitions specify the allocation chunk size
++ * for the statistics area.
++ * According to sections F.1.4.4.1.3 and F.1.4.4.2, we need at least
++ * 49 statistics bins for DC, and 245 statistics bins for AC coding.
++ * Note that we use one additional AC bin for codings with fixed
++ * probability (0.5), thus the minimum number for AC is 246.
++ *
++ * We use a compact representation with 1 byte per statistics bin,
++ * thus the numbers directly represent byte sizes.
++ * This 1 byte per statistics bin contains the meaning of the MPS
++ * (more probable symbol) in the highest bit (mask 0x80), and the
++ * index into the probability estimation state machine table
++ * in the lower bits (mask 0x7F).
++ */
++
++#define DC_STAT_BINS 64
++#define AC_STAT_BINS 256
++
++
++LOCAL(int)
++get_byte (j_decompress_ptr cinfo)
++/* Read next input byte; we do not support suspension in this module. */
++{
++ struct jpeg_source_mgr * src = cinfo->src;
++
++ if (src->bytes_in_buffer == 0)
++ if (! (*src->fill_input_buffer) (cinfo))
++ ERREXIT(cinfo, JERR_CANT_SUSPEND);
++ src->bytes_in_buffer--;
++ return GETJOCTET(*src->next_input_byte++);
++}
++
++
++/*
++ * The core arithmetic decoding routine (common in JPEG and JBIG).
++ * This needs to go as fast as possible.
++ * Machine-dependent optimization facilities
++ * are not utilized in this portable implementation.
++ * However, this code should be fairly efficient and
++ * may be a good base for further optimizations anyway.
++ *
++ * Return value is 0 or 1 (binary decision).
++ *
++ * Note: I've changed the handling of the code base & bit
++ * buffer register C compared to other implementations
++ * based on the standards layout & procedures.
++ * While it also contains both the actual base of the
++ * coding interval (16 bits) and the next-bits buffer,
++ * the cut-point between these two parts is floating
++ * (instead of fixed) with the bit shift counter CT.
++ * Thus, we also need only one (variable instead of
++ * fixed size) shift for the LPS/MPS decision, and
++ * we can get away with any renormalization update
++ * of C (except for new data insertion, of course).
++ *
++ * I've also introduced a new scheme for accessing
++ * the probability estimation state machine table,
++ * derived from Markus Kuhn's JBIG implementation.
++ */
++
++LOCAL(int)
++arith_decode (j_decompress_ptr cinfo, unsigned char *st)
++{
++ extern const INT32 jaritab[];
++ register arith_entropy_ptr e = (arith_entropy_ptr) cinfo->entropy;
++ register unsigned char nl, nm;
++ register INT32 qe, temp;
++ register int sv, data;
++
++ /* Renormalization & data input per section D.2.6 */
++ while (e->a < 0x8000L) {
++ if (--e->ct < 0) {
++ /* Need to fetch next data byte */
++ if (cinfo->unread_marker)
++ data = 0; /* stuff zero data */
++ else {
++ data = get_byte(cinfo); /* read next input byte */
++ if (data == 0xFF) { /* zero stuff or marker code */
++ do data = get_byte(cinfo);
++ while (data == 0xFF); /* swallow extra 0xFF bytes */
++ if (data == 0)
++ data = 0xFF; /* discard stuffed zero byte */
++ else {
++ /* Note: Different from the Huffman decoder, hitting
++ * a marker while processing the compressed data
++ * segment is legal in arithmetic coding.
++ * The convention is to supply zero data
++ * then until decoding is complete.
++ */
++ cinfo->unread_marker = data;
++ data = 0;
++ }
++ }
++ }
++ e->c = (e->c << 8) | data; /* insert data into C register */
++ if ((e->ct += 8) < 0) /* update bit shift counter */
++ /* Need more initial bytes */
++ if (++e->ct == 0)
++ /* Got 2 initial bytes -> re-init A and exit loop */
++ e->a = 0x8000L; /* => e->a = 0x10000L after loop exit */
++ }
++ e->a <<= 1;
++ }
++
++ /* Fetch values from our compact representation of Table D.2:
++ * Qe values and probability estimation state machine
++ */
++ sv = *st;
++ qe = jaritab[sv & 0x7F]; /* => Qe_Value */
++ nl = qe & 0xFF; qe >>= 8; /* Next_Index_LPS + Switch_MPS */
++ nm = qe & 0xFF; qe >>= 8; /* Next_Index_MPS */
++
++ /* Decode & estimation procedures per sections D.2.4 & D.2.5 */
++ temp = e->a - qe;
++ e->a = temp;
++ temp <<= e->ct;
++ if (e->c >= temp) {
++ e->c -= temp;
++ /* Conditional LPS (less probable symbol) exchange */
++ if (e->a < qe) {
++ e->a = qe;
++ *st = (sv & 0x80) ^ nm; /* Estimate_after_MPS */
++ } else {
++ e->a = qe;
++ *st = (sv & 0x80) ^ nl; /* Estimate_after_LPS */
++ sv ^= 0x80; /* Exchange LPS/MPS */
++ }
++ } else if (e->a < 0x8000L) {
++ /* Conditional MPS (more probable symbol) exchange */
++ if (e->a < qe) {
++ *st = (sv & 0x80) ^ nl; /* Estimate_after_LPS */
++ sv ^= 0x80; /* Exchange LPS/MPS */
++ } else {
++ *st = (sv & 0x80) ^ nm; /* Estimate_after_MPS */
++ }
++ }
++
++ return sv >> 7;
++}
++
++
++/*
++ * Check for a restart marker & resynchronize decoder.
++ */
++
++LOCAL(void)
++process_restart (j_decompress_ptr cinfo)
++{
++ arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
++ int ci;
++ jpeg_component_info * compptr;
++
++ /* Advance past the RSTn marker */
++ if (! (*cinfo->marker->read_restart_marker) (cinfo))
++ ERREXIT(cinfo, JERR_CANT_SUSPEND);
++
++ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
++ compptr = cinfo->cur_comp_info[ci];
++ /* Re-initialize statistics areas */
++ if (cinfo->progressive_mode == 0 || (cinfo->Ss == 0 && cinfo->Ah == 0)) {
++ MEMZERO(entropy->dc_stats[compptr->dc_tbl_no], DC_STAT_BINS);
++ /* Reset DC predictions to 0 */
++ entropy->last_dc_val[ci] = 0;
++ entropy->dc_context[ci] = 0;
++ }
++ if (cinfo->progressive_mode == 0 || cinfo->Ss) {
++ MEMZERO(entropy->ac_stats[compptr->ac_tbl_no], AC_STAT_BINS);
++ }
++ }
++
++ /* Reset arithmetic decoding variables */
++ entropy->c = 0;
++ entropy->a = 0;
++ entropy->ct = -16; /* force reading 2 initial bytes to fill C */
++
++ /* Reset restart counter */
++ entropy->restarts_to_go = cinfo->restart_interval;
++}
++
++
++/*
++ * Arithmetic MCU decoding.
++ * Each of these routines decodes and returns one MCU's worth of
++ * arithmetic-compressed coefficients.
++ * The coefficients are reordered from zigzag order into natural array order,
++ * but are not dequantized.
++ *
++ * The i'th block of the MCU is stored into the block pointed to by
++ * MCU_data[i]. WE ASSUME THIS AREA IS INITIALLY ZEROED BY THE CALLER.
++ */
++
++/*
++ * MCU decoding for DC initial scan (either spectral selection,
++ * or first pass of successive approximation).
++ */
++
++METHODDEF(boolean)
++decode_mcu_DC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
++{
++ arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
++ JBLOCKROW block;
++ unsigned char *st;
++ int blkn, ci, tbl, sign;
++ int v, m;
++
++ /* Process restart marker if needed */
++ if (cinfo->restart_interval) {
++ if (entropy->restarts_to_go == 0)
++ process_restart(cinfo);
++ entropy->restarts_to_go--;
++ }
++
++ if (entropy->ct == -1) return TRUE; /* if error do nothing */
++
++ /* Outer loop handles each block in the MCU */
++
++ for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
++ block = MCU_data[blkn];
++ ci = cinfo->MCU_membership[blkn];
++ tbl = cinfo->cur_comp_info[ci]->dc_tbl_no;
++
++ /* Sections F.2.4.1 & F.1.4.4.1: Decoding of DC coefficients */
++
++ /* Table F.4: Point to statistics bin S0 for DC coefficient coding */
++ st = entropy->dc_stats[tbl] + entropy->dc_context[ci];
++
++ /* Figure F.19: Decode_DC_DIFF */
++ if (arith_decode(cinfo, st) == 0)
++ entropy->dc_context[ci] = 0;
++ else {
++ /* Figure F.21: Decoding nonzero value v */
++ /* Figure F.22: Decoding the sign of v */
++ sign = arith_decode(cinfo, st + 1);
++ st += 2; st += sign;
++ /* Figure F.23: Decoding the magnitude category of v */
++ if ((m = arith_decode(cinfo, st)) != 0) {
++ st = entropy->dc_stats[tbl] + 20; /* Table F.4: X1 = 20 */
++ while (arith_decode(cinfo, st)) {
++ if ((m <<= 1) == 0x8000) {
++ WARNMS(cinfo, JWRN_ARITH_BAD_CODE);
++ entropy->ct = -1; /* magnitude overflow */
++ return TRUE;
++ }
++ st += 1;
++ }
++ }
++ /* Section F.1.4.4.1.2: Establish dc_context conditioning category */
++ if (m < (int) (((INT32) 1 << cinfo->arith_dc_L[tbl]) >> 1))
++ entropy->dc_context[ci] = 0; /* zero diff category */
++ else if (m > (int) (((INT32) 1 << cinfo->arith_dc_U[tbl]) >> 1))
++ entropy->dc_context[ci] = 12 + (sign * 4); /* large diff category */
++ else
++ entropy->dc_context[ci] = 4 + (sign * 4); /* small diff category */
++ v = m;
++ /* Figure F.24: Decoding the magnitude bit pattern of v */
++ st += 14;
++ while (m >>= 1)
++ if (arith_decode(cinfo, st)) v |= m;
++ v += 1; if (sign) v = -v;
++ entropy->last_dc_val[ci] += v;
++ }
++
++ /* Scale and output the DC coefficient (assumes jpeg_natural_order[0]=0) */
++ (*block)[0] = (JCOEF) (entropy->last_dc_val[ci] << cinfo->Al);
++ }
++
++ return TRUE;
++}
++
++
++/*
++ * MCU decoding for AC initial scan (either spectral selection,
++ * or first pass of successive approximation).
++ */
++
++METHODDEF(boolean)
++decode_mcu_AC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
++{
++ arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
++ JBLOCKROW block;
++ unsigned char *st;
++ int tbl, sign, k;
++ int v, m;
++
++ /* Process restart marker if needed */
++ if (cinfo->restart_interval) {
++ if (entropy->restarts_to_go == 0)
++ process_restart(cinfo);
++ entropy->restarts_to_go--;
++ }
++
++ if (entropy->ct == -1) return TRUE; /* if error do nothing */
++
++ /* There is always only one block per MCU */
++ block = MCU_data[0];
++ tbl = cinfo->cur_comp_info[0]->ac_tbl_no;
++
++ /* Sections F.2.4.2 & F.1.4.4.2: Decoding of AC coefficients */
++
++ /* Figure F.20: Decode_AC_coefficients */
++ for (k = cinfo->Ss; k <= cinfo->Se; k++) {
++ st = entropy->ac_stats[tbl] + 3 * (k - 1);
++ if (arith_decode(cinfo, st)) break; /* EOB flag */
++ while (arith_decode(cinfo, st + 1) == 0) {
++ st += 3; k++;
++ if (k > cinfo->Se) {
++ WARNMS(cinfo, JWRN_ARITH_BAD_CODE);
++ entropy->ct = -1; /* spectral overflow */
++ return TRUE;
++ }
++ }
++ /* Figure F.21: Decoding nonzero value v */
++ /* Figure F.22: Decoding the sign of v */
++ entropy->ac_stats[tbl][245] = 0;
++ sign = arith_decode(cinfo, entropy->ac_stats[tbl] + 245);
++ st += 2;
++ /* Figure F.23: Decoding the magnitude category of v */
++ if ((m = arith_decode(cinfo, st)) != 0) {
++ if (arith_decode(cinfo, st)) {
++ m <<= 1;
++ st = entropy->ac_stats[tbl] +
++ (k <= cinfo->arith_ac_K[tbl] ? 189 : 217);
++ while (arith_decode(cinfo, st)) {
++ if ((m <<= 1) == 0x8000) {
++ WARNMS(cinfo, JWRN_ARITH_BAD_CODE);
++ entropy->ct = -1; /* magnitude overflow */
++ return TRUE;
++ }
++ st += 1;
++ }
++ }
++ }
++ v = m;
++ /* Figure F.24: Decoding the magnitude bit pattern of v */
++ st += 14;
++ while (m >>= 1)
++ if (arith_decode(cinfo, st)) v |= m;
++ v += 1; if (sign) v = -v;
++ /* Scale and output coefficient in natural (dezigzagged) order */
++ (*block)[jpeg_natural_order[k]] = (JCOEF) (v << cinfo->Al);
++ }
++
++ return TRUE;
++}
++
++
++/*
++ * MCU decoding for DC successive approximation refinement scan.
++ */
++
++METHODDEF(boolean)
++decode_mcu_DC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
++{
++ arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
++ unsigned char st[4];
++ int p1, blkn;
++
++ /* Process restart marker if needed */
++ if (cinfo->restart_interval) {
++ if (entropy->restarts_to_go == 0)
++ process_restart(cinfo);
++ entropy->restarts_to_go--;
++ }
++
++ p1 = 1 << cinfo->Al; /* 1 in the bit position being coded */
++
++ /* Outer loop handles each block in the MCU */
++
++ for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
++ st[0] = 0; /* use fixed probability estimation */
++ /* Encoded data is simply the next bit of the two's-complement DC value */
++ if (arith_decode(cinfo, st))
++ MCU_data[blkn][0][0] |= p1;
++ }
++
++ return TRUE;
++}
++
++
++/*
++ * MCU decoding for AC successive approximation refinement scan.
++ */
++
++METHODDEF(boolean)
++decode_mcu_AC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
++{
++ arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
++ JBLOCKROW block;
++ JCOEFPTR thiscoef;
++ unsigned char *st;
++ int tbl, k, kex;
++ int p1, m1;
++
++ /* Process restart marker if needed */
++ if (cinfo->restart_interval) {
++ if (entropy->restarts_to_go == 0)
++ process_restart(cinfo);
++ entropy->restarts_to_go--;
++ }
++
++ if (entropy->ct == -1) return TRUE; /* if error do nothing */
++
++ /* There is always only one block per MCU */
++ block = MCU_data[0];
++ tbl = cinfo->cur_comp_info[0]->ac_tbl_no;
++
++ p1 = 1 << cinfo->Al; /* 1 in the bit position being coded */
++ m1 = (-1) << cinfo->Al; /* -1 in the bit position being coded */
++
++ /* Establish EOBx (previous stage end-of-block) index */
++ for (kex = cinfo->Se + 1; kex > 1; kex--)
++ if ((*block)[jpeg_natural_order[kex - 1]]) break;
++
++ for (k = cinfo->Ss; k <= cinfo->Se; k++) {
++ st = entropy->ac_stats[tbl] + 3 * (k - 1);
++ if (k >= kex)
++ if (arith_decode(cinfo, st)) break; /* EOB flag */
++ for (;;) {
++ thiscoef = *block + jpeg_natural_order[k];
++ if (*thiscoef) { /* previously nonzero coef */
++ if (arith_decode(cinfo, st + 2))
++ if (*thiscoef < 0)
++ *thiscoef += m1;
++ else
++ *thiscoef += p1;
++ break;
++ }
++ if (arith_decode(cinfo, st + 1)) { /* newly nonzero coef */
++ entropy->ac_stats[tbl][245] = 0;
++ if (arith_decode(cinfo, entropy->ac_stats[tbl] + 245))
++ *thiscoef = m1;
++ else
++ *thiscoef = p1;
++ break;
++ }
++ st += 3; k++;
++ if (k > cinfo->Se) {
++ WARNMS(cinfo, JWRN_ARITH_BAD_CODE);
++ entropy->ct = -1; /* spectral overflow */
++ return TRUE;
++ }
++ }
++ }
++
++ return TRUE;
++}
++
++
++/*
++ * Decode one MCU's worth of arithmetic-compressed coefficients.
++ */
++
++METHODDEF(boolean)
++decode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
++{
++ arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
++ jpeg_component_info * compptr;
++ JBLOCKROW block;
++ unsigned char *st;
++ int blkn, ci, tbl, sign, k;
++ int v, m;
++
++ /* Process restart marker if needed */
++ if (cinfo->restart_interval) {
++ if (entropy->restarts_to_go == 0)
++ process_restart(cinfo);
++ entropy->restarts_to_go--;
++ }
++
++ if (entropy->ct == -1) return TRUE; /* if error do nothing */
++
++ /* Outer loop handles each block in the MCU */
++
++ for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
++ block = MCU_data[blkn];
++ ci = cinfo->MCU_membership[blkn];
++ compptr = cinfo->cur_comp_info[ci];
++
++ /* Sections F.2.4.1 & F.1.4.4.1: Decoding of DC coefficients */
++
++ tbl = compptr->dc_tbl_no;
++
++ /* Table F.4: Point to statistics bin S0 for DC coefficient coding */
++ st = entropy->dc_stats[tbl] + entropy->dc_context[ci];
++
++ /* Figure F.19: Decode_DC_DIFF */
++ if (arith_decode(cinfo, st) == 0)
++ entropy->dc_context[ci] = 0;
++ else {
++ /* Figure F.21: Decoding nonzero value v */
++ /* Figure F.22: Decoding the sign of v */
++ sign = arith_decode(cinfo, st + 1);
++ st += 2; st += sign;
++ /* Figure F.23: Decoding the magnitude category of v */
++ if ((m = arith_decode(cinfo, st)) != 0) {
++ st = entropy->dc_stats[tbl] + 20; /* Table F.4: X1 = 20 */
++ while (arith_decode(cinfo, st)) {
++ if ((m <<= 1) == 0x8000) {
++ WARNMS(cinfo, JWRN_ARITH_BAD_CODE);
++ entropy->ct = -1; /* magnitude overflow */
++ return TRUE;
++ }
++ st += 1;
++ }
++ }
++ /* Section F.1.4.4.1.2: Establish dc_context conditioning category */
++ if (m < (int) (((INT32) 1 << cinfo->arith_dc_L[tbl]) >> 1))
++ entropy->dc_context[ci] = 0; /* zero diff category */
++ else if (m > (int) (((INT32) 1 << cinfo->arith_dc_U[tbl]) >> 1))
++ entropy->dc_context[ci] = 12 + (sign * 4); /* large diff category */
++ else
++ entropy->dc_context[ci] = 4 + (sign * 4); /* small diff category */
++ v = m;
++ /* Figure F.24: Decoding the magnitude bit pattern of v */
++ st += 14;
++ while (m >>= 1)
++ if (arith_decode(cinfo, st)) v |= m;
++ v += 1; if (sign) v = -v;
++ entropy->last_dc_val[ci] += v;
++ }
++
++ (*block)[0] = (JCOEF) entropy->last_dc_val[ci];
++
++ /* Sections F.2.4.2 & F.1.4.4.2: Decoding of AC coefficients */
++
++ tbl = compptr->ac_tbl_no;
++
++ /* Figure F.20: Decode_AC_coefficients */
++ for (k = 1; k < DCTSIZE2; k++) {
++ st = entropy->ac_stats[tbl] + 3 * (k - 1);
++ if (arith_decode(cinfo, st)) break; /* EOB flag */
++ while (arith_decode(cinfo, st + 1) == 0) {
++ st += 3; k++;
++ if (k >= DCTSIZE2) {
++ WARNMS(cinfo, JWRN_ARITH_BAD_CODE);
++ entropy->ct = -1; /* spectral overflow */
++ return TRUE;
++ }
++ }
++ /* Figure F.21: Decoding nonzero value v */
++ /* Figure F.22: Decoding the sign of v */
++ entropy->ac_stats[tbl][245] = 0;
++ sign = arith_decode(cinfo, entropy->ac_stats[tbl] + 245);
++ st += 2;
++ /* Figure F.23: Decoding the magnitude category of v */
++ if ((m = arith_decode(cinfo, st)) != 0) {
++ if (arith_decode(cinfo, st)) {
++ m <<= 1;
++ st = entropy->ac_stats[tbl] +
++ (k <= cinfo->arith_ac_K[tbl] ? 189 : 217);
++ while (arith_decode(cinfo, st)) {
++ if ((m <<= 1) == 0x8000) {
++ WARNMS(cinfo, JWRN_ARITH_BAD_CODE);
++ entropy->ct = -1; /* magnitude overflow */
++ return TRUE;
++ }
++ st += 1;
++ }
++ }
++ }
++ v = m;
++ /* Figure F.24: Decoding the magnitude bit pattern of v */
++ st += 14;
++ while (m >>= 1)
++ if (arith_decode(cinfo, st)) v |= m;
++ v += 1; if (sign) v = -v;
++ (*block)[jpeg_natural_order[k]] = (JCOEF) v;
++ }
++ }
++
++ return TRUE;
++}
++
++
++/*
++ * Initialize for an arithmetic-compressed scan.
++ */
++
++METHODDEF(void)
++start_pass (j_decompress_ptr cinfo)
++{
++ arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
++ int ci, tbl;
++ jpeg_component_info * compptr;
++
++ if (cinfo->progressive_mode) {
++ /* Validate progressive scan parameters */
++ if (cinfo->Ss == 0) {
++ if (cinfo->Se != 0)
++ goto bad;
++ } else {
++ /* need not check Ss/Se < 0 since they came from unsigned bytes */
++ if (cinfo->Se < cinfo->Ss || cinfo->Se >= DCTSIZE2)
++ goto bad;
++ /* AC scans may have only one component */
++ if (cinfo->comps_in_scan != 1)
++ goto bad;
++ }
++ if (cinfo->Ah != 0) {
++ /* Successive approximation refinement scan: must have Al = Ah-1. */
++ if (cinfo->Ah-1 != cinfo->Al)
++ goto bad;
++ }
++ if (cinfo->Al > 13) { /* need not check for < 0 */
++ bad:
++ ERREXIT4(cinfo, JERR_BAD_PROGRESSION,
++ cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al);
++ }
++ /* Update progression status, and verify that scan order is legal.
++ * Note that inter-scan inconsistencies are treated as warnings
++ * not fatal errors ... not clear if this is right way to behave.
++ */
++ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
++ int coefi, cindex = cinfo->cur_comp_info[ci]->component_index;
++ int *coef_bit_ptr = & cinfo->coef_bits[cindex][0];
++ if (cinfo->Ss && coef_bit_ptr[0] < 0) /* AC without prior DC scan */
++ WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, 0);
++ for (coefi = cinfo->Ss; coefi <= cinfo->Se; coefi++) {
++ int expected = (coef_bit_ptr[coefi] < 0) ? 0 : coef_bit_ptr[coefi];
++ if (cinfo->Ah != expected)
++ WARNMS2(cinfo, JWRN_BOGUS_PROGRESSION, cindex, coefi);
++ coef_bit_ptr[coefi] = cinfo->Al;
++ }
++ }
++ /* Select MCU decoding routine */
++ if (cinfo->Ah == 0) {
++ if (cinfo->Ss == 0)
++ entropy->pub.decode_mcu = decode_mcu_DC_first;
++ else
++ entropy->pub.decode_mcu = decode_mcu_AC_first;
++ } else {
++ if (cinfo->Ss == 0)
++ entropy->pub.decode_mcu = decode_mcu_DC_refine;
++ else
++ entropy->pub.decode_mcu = decode_mcu_AC_refine;
++ }
++ } else {
++ /* Check that the scan parameters Ss, Se, Ah/Al are OK for sequential JPEG.
++ * This ought to be an error condition, but we make it a warning because
++ * there are some baseline files out there with all zeroes in these bytes.
++ */
++ if (cinfo->Ss != 0 || cinfo->Se != DCTSIZE2-1 ||
++ cinfo->Ah != 0 || cinfo->Al != 0)
++ WARNMS(cinfo, JWRN_NOT_SEQUENTIAL);
++ /* Select MCU decoding routine */
++ entropy->pub.decode_mcu = decode_mcu;
++ }
++
++ for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
++ compptr = cinfo->cur_comp_info[ci];
++ /* Allocate & initialize requested statistics areas */
++ if (cinfo->progressive_mode == 0 || (cinfo->Ss == 0 && cinfo->Ah == 0)) {
++ tbl = compptr->dc_tbl_no;
++ if (tbl < 0 || tbl >= NUM_ARITH_TBLS)
++ ERREXIT1(cinfo, JERR_NO_ARITH_TABLE, tbl);
++ if (entropy->dc_stats[tbl] == NULL)
++ entropy->dc_stats[tbl] = (unsigned char *) (*cinfo->mem->alloc_small)
++ ((j_common_ptr) cinfo, JPOOL_IMAGE, DC_STAT_BINS);
++ MEMZERO(entropy->dc_stats[tbl], DC_STAT_BINS);
++ /* Initialize DC predictions to 0 */
++ entropy->last_dc_val[ci] = 0;
++ entropy->dc_context[ci] = 0;
++ }
++ if (cinfo->progressive_mode == 0 || cinfo->Ss) {
++ tbl = compptr->ac_tbl_no;
++ if (tbl < 0 || tbl >= NUM_ARITH_TBLS)
++ ERREXIT1(cinfo, JERR_NO_ARITH_TABLE, tbl);
++ if (entropy->ac_stats[tbl] == NULL)
++ entropy->ac_stats[tbl] = (unsigned char *) (*cinfo->mem->alloc_small)
++ ((j_common_ptr) cinfo, JPOOL_IMAGE, AC_STAT_BINS);
++ MEMZERO(entropy->ac_stats[tbl], AC_STAT_BINS);
++ }
++ }
++
++ /* Initialize arithmetic decoding variables */
++ entropy->c = 0;
++ entropy->a = 0;
++ entropy->ct = -16; /* force reading 2 initial bytes to fill C */
++
++ /* Initialize restart counter */
++ entropy->restarts_to_go = cinfo->restart_interval;
++}
++
++
++/*
++ * Module initialization routine for arithmetic entropy decoding.
++ */
++
++GLOBAL(void)
++jinit_arith_decoder (j_decompress_ptr cinfo)
++{
++ arith_entropy_ptr entropy;
++ int i;
++
++ entropy = (arith_entropy_ptr)
++ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
++ SIZEOF(arith_entropy_decoder));
++ cinfo->entropy = (struct jpeg_entropy_decoder *) entropy;
++ entropy->pub.start_pass = start_pass;
++
++ /* Mark tables unallocated */
++ for (i = 0; i < NUM_ARITH_TBLS; i++) {
++ entropy->dc_stats[i] = NULL;
++ entropy->ac_stats[i] = NULL;
++ }
++
++ if (cinfo->progressive_mode) {
++ /* Create progression status table */
++ int *coef_bit_ptr, ci;
++ cinfo->coef_bits = (int (*)[DCTSIZE2])
++ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
++ cinfo->num_components*DCTSIZE2*SIZEOF(int));
++ coef_bit_ptr = & cinfo->coef_bits[0][0];
++ for (ci = 0; ci < cinfo->num_components; ci++)
++ for (i = 0; i < DCTSIZE2; i++)
++ *coef_bit_ptr++ = -1;
++ }
++}
+diff --git a/jdmaster.c b/jdmaster.c
+index 8314b67..537abc7 100644
+--- a/jdmaster.c
++++ b/jdmaster.c
+@@ -384,7 +384,7 @@ master_selection (j_decompress_ptr cinfo)
+ jinit_inverse_dct(cinfo);
+ /* Entropy decoding: either Huffman or arithmetic coding. */
+ if (cinfo->arith_code) {
+- ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
++ jinit_arith_decoder(cinfo);
+ } else {
+ if (cinfo->progressive_mode) {
+ #ifdef D_PROGRESSIVE_SUPPORTED
+diff --git a/jdtrans.c b/jdtrans.c
+index 6c0ab71..fcc9ae9 100644
+--- a/jdtrans.c
++++ b/jdtrans.c
+@@ -101,7 +101,7 @@ transdecode_master_selection (j_decompress_ptr cinfo)
+
+ /* Entropy decoding: either Huffman or arithmetic coding. */
+ if (cinfo->arith_code) {
+- ERREXIT(cinfo, JERR_ARITH_NOTIMPL);
++ jinit_arith_decoder(cinfo);
+ } else {
+ if (cinfo->progressive_mode) {
+ #ifdef D_PROGRESSIVE_SUPPORTED
+diff --git a/jerror.h b/jerror.h
+index fc2fffe..109e3d3 100644
+--- a/jerror.h
++++ b/jerror.h
+@@ -93,6 +93,7 @@ JMESSAGE(JERR_MISSING_DATA, "Scan script does not transmit all data")
+ JMESSAGE(JERR_MODE_CHANGE, "Invalid color quantization mode change")
+ JMESSAGE(JERR_NOTIMPL, "Not implemented yet")
+ JMESSAGE(JERR_NOT_COMPILED, "Requested feature was omitted at compile time")
++JMESSAGE(JERR_NO_ARITH_TABLE, "Arithmetic table 0x%02x was not defined")
+ JMESSAGE(JERR_NO_BACKING_STORE, "Backing store not supported")
+ JMESSAGE(JERR_NO_HUFF_TABLE, "Huffman table 0x%02x was not defined")
+ JMESSAGE(JERR_NO_IMAGE, "JPEG datastream contains no image")
+@@ -170,6 +171,7 @@ JMESSAGE(JTRC_UNKNOWN_IDS,
+ JMESSAGE(JTRC_XMS_CLOSE, "Freed XMS handle %u")
+ JMESSAGE(JTRC_XMS_OPEN, "Obtained XMS handle %u")
+ JMESSAGE(JWRN_ADOBE_XFORM, "Unknown Adobe color transform code %d")
++JMESSAGE(JWRN_ARITH_BAD_CODE, "Corrupt JPEG data: bad arithmetic code")
+ JMESSAGE(JWRN_BOGUS_PROGRESSION,
+ "Inconsistent progression sequence for component %d coefficient %d")
+ JMESSAGE(JWRN_EXTRANEOUS_DATA,
+diff --git a/jmorecfg.h b/jmorecfg.h
+index 0e7fb72..4d66335 100644
+--- a/jmorecfg.h
++++ b/jmorecfg.h
+@@ -283,7 +283,7 @@ typedef int boolean;
+
+ /* Decoder capability options: */
+
+-#undef D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
++#define D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
+ #define D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
+ #define D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
+ #define SAVE_MARKERS_SUPPORTED /* jpeg_save_markers() needed? */
+diff --git a/jpegint.h b/jpegint.h
+index 7a31f51..78bb1cf 100644
+--- a/jpegint.h
++++ b/jpegint.h
+@@ -313,6 +313,7 @@ struct jpeg_color_quantizer {
+ #define jinit_marker_reader jIMReader
+ #define jinit_huff_decoder jIHDecoder
+ #define jinit_phuff_decoder jIPHDecoder
++#define jinit_arith_decoder jIADecoder
+ #define jinit_inverse_dct jIIDCT
+ #define jinit_upsampler jIUpsampler
+ #define jinit_color_deconverter jIDColor
+@@ -358,6 +359,7 @@ EXTERN(void) jinit_input_controller JPP((j_decompress_ptr cinfo));
+ EXTERN(void) jinit_marker_reader JPP((j_decompress_ptr cinfo));
+ EXTERN(void) jinit_huff_decoder JPP((j_decompress_ptr cinfo));
+ EXTERN(void) jinit_phuff_decoder JPP((j_decompress_ptr cinfo));
++EXTERN(void) jinit_arith_decoder JPP((j_decompress_ptr cinfo));
+ EXTERN(void) jinit_inverse_dct JPP((j_decompress_ptr cinfo));
+ EXTERN(void) jinit_upsampler JPP((j_decompress_ptr cinfo));
+ EXTERN(void) jinit_color_deconverter JPP((j_decompress_ptr cinfo));
+--
+1.7.2.3
+
projects / packages / libjpeg-turbo.git / commitdiff