gecko-dev/media/libjpeg/jcarith.c
Bobby Holley 2d0b90011e Bug 584894 - Move libjpeg to media/libjpeg. r=khuey
--HG--
rename : jpeg/MOZCHANGES => media/libjpeg/MOZCHANGES
rename : jpeg/Makefile.in => media/libjpeg/Makefile.in
rename : jpeg/README => media/libjpeg/README
rename : jpeg/README-turbo.txt => media/libjpeg/README-turbo.txt
rename : jpeg/cderror.h => media/libjpeg/cderror.h
rename : jpeg/cdjpeg.h => media/libjpeg/cdjpeg.h
rename : jpeg/jaricom.c => media/libjpeg/jaricom.c
rename : jpeg/jcapimin.c => media/libjpeg/jcapimin.c
rename : jpeg/jcapistd.c => media/libjpeg/jcapistd.c
rename : jpeg/jcarith.c => media/libjpeg/jcarith.c
rename : jpeg/jccoefct.c => media/libjpeg/jccoefct.c
rename : jpeg/jccolor.c => media/libjpeg/jccolor.c
rename : jpeg/jcdctmgr.c => media/libjpeg/jcdctmgr.c
rename : jpeg/jchuff.c => media/libjpeg/jchuff.c
rename : jpeg/jchuff.h => media/libjpeg/jchuff.h
rename : jpeg/jcinit.c => media/libjpeg/jcinit.c
rename : jpeg/jcmainct.c => media/libjpeg/jcmainct.c
rename : jpeg/jcmarker.c => media/libjpeg/jcmarker.c
rename : jpeg/jcmaster.c => media/libjpeg/jcmaster.c
rename : jpeg/jcomapi.c => media/libjpeg/jcomapi.c
rename : jpeg/jconfig.h => media/libjpeg/jconfig.h
rename : jpeg/jconfig.h.in => media/libjpeg/jconfig.h.in
rename : jpeg/jcparam.c => media/libjpeg/jcparam.c
rename : jpeg/jcphuff.c => media/libjpeg/jcphuff.c
rename : jpeg/jcprepct.c => media/libjpeg/jcprepct.c
rename : jpeg/jcsample.c => media/libjpeg/jcsample.c
rename : jpeg/jdapimin.c => media/libjpeg/jdapimin.c
rename : jpeg/jdapistd.c => media/libjpeg/jdapistd.c
rename : jpeg/jdarith.c => media/libjpeg/jdarith.c
rename : jpeg/jdatadst.c => media/libjpeg/jdatadst.c
rename : jpeg/jdatasrc.c => media/libjpeg/jdatasrc.c
rename : jpeg/jdcoefct.c => media/libjpeg/jdcoefct.c
rename : jpeg/jdcolor.c => media/libjpeg/jdcolor.c
rename : jpeg/jdct.h => media/libjpeg/jdct.h
rename : jpeg/jddctmgr.c => media/libjpeg/jddctmgr.c
rename : jpeg/jdhuff.c => media/libjpeg/jdhuff.c
rename : jpeg/jdhuff.h => media/libjpeg/jdhuff.h
rename : jpeg/jdinput.c => media/libjpeg/jdinput.c
rename : jpeg/jdmainct.c => media/libjpeg/jdmainct.c
rename : jpeg/jdmarker.c => media/libjpeg/jdmarker.c
rename : jpeg/jdmaster.c => media/libjpeg/jdmaster.c
rename : jpeg/jdmerge.c => media/libjpeg/jdmerge.c
rename : jpeg/jdphuff.c => media/libjpeg/jdphuff.c
rename : jpeg/jdpostct.c => media/libjpeg/jdpostct.c
rename : jpeg/jdsample.c => media/libjpeg/jdsample.c
rename : jpeg/jdtrans.c => media/libjpeg/jdtrans.c
rename : jpeg/jerror.c => media/libjpeg/jerror.c
rename : jpeg/jerror.h => media/libjpeg/jerror.h
rename : jpeg/jfdctflt.c => media/libjpeg/jfdctflt.c
rename : jpeg/jfdctfst.c => media/libjpeg/jfdctfst.c
rename : jpeg/jfdctint.c => media/libjpeg/jfdctint.c
rename : jpeg/jidctflt.c => media/libjpeg/jidctflt.c
rename : jpeg/jidctfst.c => media/libjpeg/jidctfst.c
rename : jpeg/jidctint.c => media/libjpeg/jidctint.c
rename : jpeg/jidctred.c => media/libjpeg/jidctred.c
rename : jpeg/jinclude.h => media/libjpeg/jinclude.h
rename : jpeg/jmemmgr.c => media/libjpeg/jmemmgr.c
rename : jpeg/jmemnobs.c => media/libjpeg/jmemnobs.c
rename : jpeg/jmemsys.h => media/libjpeg/jmemsys.h
rename : jpeg/jmorecfg.h => media/libjpeg/jmorecfg.h
rename : jpeg/jpegcomp.h => media/libjpeg/jpegcomp.h
rename : jpeg/jpegint.h => media/libjpeg/jpegint.h
rename : jpeg/jpeglib.h => media/libjpeg/jpeglib.h
rename : jpeg/jquant1.c => media/libjpeg/jquant1.c
rename : jpeg/jquant2.c => media/libjpeg/jquant2.c
rename : jpeg/jsimd.h => media/libjpeg/jsimd.h
rename : jpeg/jsimd_none.c => media/libjpeg/jsimd_none.c
rename : jpeg/jsimddct.h => media/libjpeg/jsimddct.h
rename : jpeg/jutils.c => media/libjpeg/jutils.c
rename : jpeg/jversion.h => media/libjpeg/jversion.h
rename : jpeg/simd/Makefile.in => media/libjpeg/simd/Makefile.in
rename : jpeg/simd/jcclrmmx.asm => media/libjpeg/simd/jcclrmmx.asm
rename : jpeg/simd/jcclrss2-64.asm => media/libjpeg/simd/jcclrss2-64.asm
rename : jpeg/simd/jcclrss2.asm => media/libjpeg/simd/jcclrss2.asm
rename : jpeg/simd/jccolmmx.asm => media/libjpeg/simd/jccolmmx.asm
rename : jpeg/simd/jccolss2-64.asm => media/libjpeg/simd/jccolss2-64.asm
rename : jpeg/simd/jccolss2.asm => media/libjpeg/simd/jccolss2.asm
rename : jpeg/simd/jcolsamp.inc => media/libjpeg/simd/jcolsamp.inc
rename : jpeg/simd/jcqnt3dn.asm => media/libjpeg/simd/jcqnt3dn.asm
rename : jpeg/simd/jcqntmmx.asm => media/libjpeg/simd/jcqntmmx.asm
rename : jpeg/simd/jcqnts2f-64.asm => media/libjpeg/simd/jcqnts2f-64.asm
rename : jpeg/simd/jcqnts2f.asm => media/libjpeg/simd/jcqnts2f.asm
rename : jpeg/simd/jcqnts2i-64.asm => media/libjpeg/simd/jcqnts2i-64.asm
rename : jpeg/simd/jcqnts2i.asm => media/libjpeg/simd/jcqnts2i.asm
rename : jpeg/simd/jcqntsse.asm => media/libjpeg/simd/jcqntsse.asm
rename : jpeg/simd/jcsammmx.asm => media/libjpeg/simd/jcsammmx.asm
rename : jpeg/simd/jcsamss2-64.asm => media/libjpeg/simd/jcsamss2-64.asm
rename : jpeg/simd/jcsamss2.asm => media/libjpeg/simd/jcsamss2.asm
rename : jpeg/simd/jdclrmmx.asm => media/libjpeg/simd/jdclrmmx.asm
rename : jpeg/simd/jdclrss2-64.asm => media/libjpeg/simd/jdclrss2-64.asm
rename : jpeg/simd/jdclrss2.asm => media/libjpeg/simd/jdclrss2.asm
rename : jpeg/simd/jdcolmmx.asm => media/libjpeg/simd/jdcolmmx.asm
rename : jpeg/simd/jdcolss2-64.asm => media/libjpeg/simd/jdcolss2-64.asm
rename : jpeg/simd/jdcolss2.asm => media/libjpeg/simd/jdcolss2.asm
rename : jpeg/simd/jdct.inc => media/libjpeg/simd/jdct.inc
rename : jpeg/simd/jdmermmx.asm => media/libjpeg/simd/jdmermmx.asm
rename : jpeg/simd/jdmerss2-64.asm => media/libjpeg/simd/jdmerss2-64.asm
rename : jpeg/simd/jdmerss2.asm => media/libjpeg/simd/jdmerss2.asm
rename : jpeg/simd/jdmrgmmx.asm => media/libjpeg/simd/jdmrgmmx.asm
rename : jpeg/simd/jdmrgss2-64.asm => media/libjpeg/simd/jdmrgss2-64.asm
rename : jpeg/simd/jdmrgss2.asm => media/libjpeg/simd/jdmrgss2.asm
rename : jpeg/simd/jdsammmx.asm => media/libjpeg/simd/jdsammmx.asm
rename : jpeg/simd/jdsamss2-64.asm => media/libjpeg/simd/jdsamss2-64.asm
rename : jpeg/simd/jdsamss2.asm => media/libjpeg/simd/jdsamss2.asm
rename : jpeg/simd/jf3dnflt.asm => media/libjpeg/simd/jf3dnflt.asm
rename : jpeg/simd/jfmmxfst.asm => media/libjpeg/simd/jfmmxfst.asm
rename : jpeg/simd/jfmmxint.asm => media/libjpeg/simd/jfmmxint.asm
rename : jpeg/simd/jfss2fst-64.asm => media/libjpeg/simd/jfss2fst-64.asm
rename : jpeg/simd/jfss2fst.asm => media/libjpeg/simd/jfss2fst.asm
rename : jpeg/simd/jfss2int-64.asm => media/libjpeg/simd/jfss2int-64.asm
rename : jpeg/simd/jfss2int.asm => media/libjpeg/simd/jfss2int.asm
rename : jpeg/simd/jfsseflt-64.asm => media/libjpeg/simd/jfsseflt-64.asm
rename : jpeg/simd/jfsseflt.asm => media/libjpeg/simd/jfsseflt.asm
rename : jpeg/simd/ji3dnflt.asm => media/libjpeg/simd/ji3dnflt.asm
rename : jpeg/simd/jimmxfst.asm => media/libjpeg/simd/jimmxfst.asm
rename : jpeg/simd/jimmxint.asm => media/libjpeg/simd/jimmxint.asm
rename : jpeg/simd/jimmxred.asm => media/libjpeg/simd/jimmxred.asm
rename : jpeg/simd/jiss2flt-64.asm => media/libjpeg/simd/jiss2flt-64.asm
rename : jpeg/simd/jiss2flt.asm => media/libjpeg/simd/jiss2flt.asm
rename : jpeg/simd/jiss2fst-64.asm => media/libjpeg/simd/jiss2fst-64.asm
rename : jpeg/simd/jiss2fst.asm => media/libjpeg/simd/jiss2fst.asm
rename : jpeg/simd/jiss2int-64.asm => media/libjpeg/simd/jiss2int-64.asm
rename : jpeg/simd/jiss2int.asm => media/libjpeg/simd/jiss2int.asm
rename : jpeg/simd/jiss2red-64.asm => media/libjpeg/simd/jiss2red-64.asm
rename : jpeg/simd/jiss2red.asm => media/libjpeg/simd/jiss2red.asm
rename : jpeg/simd/jisseflt.asm => media/libjpeg/simd/jisseflt.asm
rename : jpeg/simd/jsimd.h => media/libjpeg/simd/jsimd.h
rename : jpeg/simd/jsimd_i386.c => media/libjpeg/simd/jsimd_i386.c
rename : jpeg/simd/jsimd_x86_64.c => media/libjpeg/simd/jsimd_x86_64.c
rename : jpeg/simd/jsimdcfg.inc => media/libjpeg/simd/jsimdcfg.inc
rename : jpeg/simd/jsimdcfg.inc.h => media/libjpeg/simd/jsimdcfg.inc.h
rename : jpeg/simd/jsimdcpu.asm => media/libjpeg/simd/jsimdcpu.asm
rename : jpeg/simd/jsimdext.inc => media/libjpeg/simd/jsimdext.inc
rename : jpeg/transupp.h => media/libjpeg/transupp.h
2011-10-17 21:25:53 -07:00

926 lines
28 KiB
C

/*
* jcarith.c
*
* Developed 1997-2009 by Guido Vollbeding.
* 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 portable arithmetic entropy encoding 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 encoder object for arithmetic encoding. */
typedef struct {
struct jpeg_entropy_encoder pub; /* public fields */
INT32 c; /* C register, base of coding interval, layout as in sec. D.1.3 */
INT32 a; /* A register, normalized size of coding interval */
INT32 sc; /* counter for stacked 0xFF values which might overflow */
INT32 zc; /* counter for pending 0x00 output values which might *
* be discarded at the end ("Pacman" termination) */
int ct; /* bit shift counter, determines when next byte will be written */
int buffer; /* buffer for most recent output byte != 0xFF */
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 */
int next_restart_num; /* next restart number to write (0-7) */
/* Pointers to statistics areas (these workspaces have image lifespan) */
unsigned char * dc_stats[NUM_ARITH_TBLS];
unsigned char * ac_stats[NUM_ARITH_TBLS];
/* Statistics bin for coding with fixed probability 0.5 */
unsigned char fixed_bin[4];
} arith_entropy_encoder;
typedef arith_entropy_encoder * 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.
*
* 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
/* NOTE: Uncomment the following #define if you want to use the
* given formula for calculating the AC conditioning parameter Kx
* for spectral selection progressive coding in section G.1.3.2
* of the spec (Kx = Kmin + SRL (8 + Se - Kmin) 4).
* Although the spec and P&M authors claim that this "has proven
* to give good results for 8 bit precision samples", I'm not
* convinced yet that this is really beneficial.
* Early tests gave only very marginal compression enhancements
* (a few - around 5 or so - bytes even for very large files),
* which would turn out rather negative if we'd suppress the
* DAC (Define Arithmetic Conditioning) marker segments for
* the default parameters in the future.
* Note that currently the marker writing module emits 12-byte
* DAC segments for a full-component scan in a color image.
* This is not worth worrying about IMHO. However, since the
* spec defines the default values to be used if the tables
* are omitted (unlike Huffman tables, which are required
* anyway), one might optimize this behaviour in the future,
* and then it would be disadvantageous to use custom tables if
* they don't provide sufficient gain to exceed the DAC size.
*
* On the other hand, I'd consider it as a reasonable result
* that the conditioning has no significant influence on the
* compression performance. This means that the basic
* statistical model is already rather stable.
*
* Thus, at the moment, we use the default conditioning values
* anyway, and do not use the custom formula.
*
#define CALCULATE_SPECTRAL_CONDITIONING
*/
/* IRIGHT_SHIFT is like RIGHT_SHIFT, but works on int rather than INT32.
* We assume that int right shift is unsigned if INT32 right shift is,
* which should be safe.
*/
#ifdef RIGHT_SHIFT_IS_UNSIGNED
#define ISHIFT_TEMPS int ishift_temp;
#define IRIGHT_SHIFT(x,shft) \
((ishift_temp = (x)) < 0 ? \
(ishift_temp >> (shft)) | ((~0) << (16-(shft))) : \
(ishift_temp >> (shft)))
#else
#define ISHIFT_TEMPS
#define IRIGHT_SHIFT(x,shft) ((x) >> (shft))
#endif
LOCAL(void)
emit_byte (int val, j_compress_ptr cinfo)
/* Write next output byte; we do not support suspension in this module. */
{
struct jpeg_destination_mgr * dest = cinfo->dest;
*dest->next_output_byte++ = (JOCTET) val;
if (--dest->free_in_buffer == 0)
if (! (*dest->empty_output_buffer) (cinfo))
ERREXIT(cinfo, JERR_CANT_SUSPEND);
}
/*
* Finish up at the end of an arithmetic-compressed scan.
*/
METHODDEF(void)
finish_pass (j_compress_ptr cinfo)
{
arith_entropy_ptr e = (arith_entropy_ptr) cinfo->entropy;
INT32 temp;
/* Section D.1.8: Termination of encoding */
/* Find the e->c in the coding interval with the largest
* number of trailing zero bits */
if ((temp = (e->a - 1 + e->c) & 0xFFFF0000L) < e->c)
e->c = temp + 0x8000L;
else
e->c = temp;
/* Send remaining bytes to output */
e->c <<= e->ct;
if (e->c & 0xF8000000L) {
/* One final overflow has to be handled */
if (e->buffer >= 0) {
if (e->zc)
do emit_byte(0x00, cinfo);
while (--e->zc);
emit_byte(e->buffer + 1, cinfo);
if (e->buffer + 1 == 0xFF)
emit_byte(0x00, cinfo);
}
e->zc += e->sc; /* carry-over converts stacked 0xFF bytes to 0x00 */
e->sc = 0;
} else {
if (e->buffer == 0)
++e->zc;
else if (e->buffer >= 0) {
if (e->zc)
do emit_byte(0x00, cinfo);
while (--e->zc);
emit_byte(e->buffer, cinfo);
}
if (e->sc) {
if (e->zc)
do emit_byte(0x00, cinfo);
while (--e->zc);
do {
emit_byte(0xFF, cinfo);
emit_byte(0x00, cinfo);
} while (--e->sc);
}
}
/* Output final bytes only if they are not 0x00 */
if (e->c & 0x7FFF800L) {
if (e->zc) /* output final pending zero bytes */
do emit_byte(0x00, cinfo);
while (--e->zc);
emit_byte((e->c >> 19) & 0xFF, cinfo);
if (((e->c >> 19) & 0xFF) == 0xFF)
emit_byte(0x00, cinfo);
if (e->c & 0x7F800L) {
emit_byte((e->c >> 11) & 0xFF, cinfo);
if (((e->c >> 11) & 0xFF) == 0xFF)
emit_byte(0x00, cinfo);
}
}
}
/*
* The core arithmetic encoding 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.
*
* Parameter 'val' to be encoded may be 0 or 1 (binary decision).
*
* Note: I've added full "Pacman" termination support to the
* byte output routines, which is equivalent to the optional
* Discard_final_zeros procedure (Figure D.15) in the spec.
* Thus, we always produce the shortest possible output
* stream compliant to the spec (no trailing zero bytes,
* except for FF stuffing).
*
* I've also introduced a new scheme for accessing
* the probability estimation state machine table,
* derived from Markus Kuhn's JBIG implementation.
*/
LOCAL(void)
arith_encode (j_compress_ptr cinfo, unsigned char *st, int val)
{
register arith_entropy_ptr e = (arith_entropy_ptr) cinfo->entropy;
register unsigned char nl, nm;
register INT32 qe, temp;
register int sv;
/* Fetch values from our compact representation of Table D.2:
* Qe values and probability estimation state machine
*/
sv = *st;
qe = jpeg_aritab[sv & 0x7F]; /* => Qe_Value */
nl = qe & 0xFF; qe >>= 8; /* Next_Index_LPS + Switch_MPS */
nm = qe & 0xFF; qe >>= 8; /* Next_Index_MPS */
/* Encode & estimation procedures per sections D.1.4 & D.1.5 */
e->a -= qe;
if (val != (sv >> 7)) {
/* Encode the less probable symbol */
if (e->a >= qe) {
/* If the interval size (qe) for the less probable symbol (LPS)
* is larger than the interval size for the MPS, then exchange
* the two symbols for coding efficiency, otherwise code the LPS
* as usual: */
e->c += e->a;
e->a = qe;
}
*st = (sv & 0x80) ^ nl; /* Estimate_after_LPS */
} else {
/* Encode the more probable symbol */
if (e->a >= 0x8000L)
return; /* A >= 0x8000 -> ready, no renormalization required */
if (e->a < qe) {
/* If the interval size (qe) for the less probable symbol (LPS)
* is larger than the interval size for the MPS, then exchange
* the two symbols for coding efficiency: */
e->c += e->a;
e->a = qe;
}
*st = (sv & 0x80) ^ nm; /* Estimate_after_MPS */
}
/* Renormalization & data output per section D.1.6 */
do {
e->a <<= 1;
e->c <<= 1;
if (--e->ct == 0) {
/* Another byte is ready for output */
temp = e->c >> 19;
if (temp > 0xFF) {
/* Handle overflow over all stacked 0xFF bytes */
if (e->buffer >= 0) {
if (e->zc)
do emit_byte(0x00, cinfo);
while (--e->zc);
emit_byte(e->buffer + 1, cinfo);
if (e->buffer + 1 == 0xFF)
emit_byte(0x00, cinfo);
}
e->zc += e->sc; /* carry-over converts stacked 0xFF bytes to 0x00 */
e->sc = 0;
/* Note: The 3 spacer bits in the C register guarantee
* that the new buffer byte can't be 0xFF here
* (see page 160 in the P&M JPEG book). */
e->buffer = temp & 0xFF; /* new output byte, might overflow later */
} else if (temp == 0xFF) {
++e->sc; /* stack 0xFF byte (which might overflow later) */
} else {
/* Output all stacked 0xFF bytes, they will not overflow any more */
if (e->buffer == 0)
++e->zc;
else if (e->buffer >= 0) {
if (e->zc)
do emit_byte(0x00, cinfo);
while (--e->zc);
emit_byte(e->buffer, cinfo);
}
if (e->sc) {
if (e->zc)
do emit_byte(0x00, cinfo);
while (--e->zc);
do {
emit_byte(0xFF, cinfo);
emit_byte(0x00, cinfo);
} while (--e->sc);
}
e->buffer = temp & 0xFF; /* new output byte (can still overflow) */
}
e->c &= 0x7FFFFL;
e->ct += 8;
}
} while (e->a < 0x8000L);
}
/*
* Emit a restart marker & resynchronize predictions.
*/
LOCAL(void)
emit_restart (j_compress_ptr cinfo, int restart_num)
{
arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
int ci;
jpeg_component_info * compptr;
finish_pass(cinfo);
emit_byte(0xFF, cinfo);
emit_byte(JPEG_RST0 + restart_num, cinfo);
/* Re-initialize statistics areas */
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
compptr = cinfo->cur_comp_info[ci];
/* DC needs no table for refinement scan */
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;
}
/* AC needs no table when not present */
if (cinfo->progressive_mode == 0 || cinfo->Se) {
MEMZERO(entropy->ac_stats[compptr->ac_tbl_no], AC_STAT_BINS);
}
}
/* Reset arithmetic encoding variables */
entropy->c = 0;
entropy->a = 0x10000L;
entropy->sc = 0;
entropy->zc = 0;
entropy->ct = 11;
entropy->buffer = -1; /* empty */
}
/*
* MCU encoding for DC initial scan (either spectral selection,
* or first pass of successive approximation).
*/
METHODDEF(boolean)
encode_mcu_DC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
{
arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
JBLOCKROW block;
unsigned char *st;
int blkn, ci, tbl;
int v, v2, m;
ISHIFT_TEMPS
/* Emit restart marker if needed */
if (cinfo->restart_interval) {
if (entropy->restarts_to_go == 0) {
emit_restart(cinfo, entropy->next_restart_num);
entropy->restarts_to_go = cinfo->restart_interval;
entropy->next_restart_num++;
entropy->next_restart_num &= 7;
}
entropy->restarts_to_go--;
}
/* Encode the MCU data blocks */
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;
/* Compute the DC value after the required point transform by Al.
* This is simply an arithmetic right shift.
*/
m = IRIGHT_SHIFT((int) ((*block)[0]), cinfo->Al);
/* Sections F.1.4.1 & F.1.4.4.1: Encoding 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.4: Encode_DC_DIFF */
if ((v = m - entropy->last_dc_val[ci]) == 0) {
arith_encode(cinfo, st, 0);
entropy->dc_context[ci] = 0; /* zero diff category */
} else {
entropy->last_dc_val[ci] = m;
arith_encode(cinfo, st, 1);
/* Figure F.6: Encoding nonzero value v */
/* Figure F.7: Encoding the sign of v */
if (v > 0) {
arith_encode(cinfo, st + 1, 0); /* Table F.4: SS = S0 + 1 */
st += 2; /* Table F.4: SP = S0 + 2 */
entropy->dc_context[ci] = 4; /* small positive diff category */
} else {
v = -v;
arith_encode(cinfo, st + 1, 1); /* Table F.4: SS = S0 + 1 */
st += 3; /* Table F.4: SN = S0 + 3 */
entropy->dc_context[ci] = 8; /* small negative diff category */
}
/* Figure F.8: Encoding the magnitude category of v */
m = 0;
if (v -= 1) {
arith_encode(cinfo, st, 1);
m = 1;
v2 = v;
st = entropy->dc_stats[tbl] + 20; /* Table F.4: X1 = 20 */
while (v2 >>= 1) {
arith_encode(cinfo, st, 1);
m <<= 1;
st += 1;
}
}
arith_encode(cinfo, st, 0);
/* Section F.1.4.4.1.2: Establish dc_context conditioning category */
if (m < (int) ((1L << cinfo->arith_dc_L[tbl]) >> 1))
entropy->dc_context[ci] = 0; /* zero diff category */
else if (m > (int) ((1L << cinfo->arith_dc_U[tbl]) >> 1))
entropy->dc_context[ci] += 8; /* large diff category */
/* Figure F.9: Encoding the magnitude bit pattern of v */
st += 14;
while (m >>= 1)
arith_encode(cinfo, st, (m & v) ? 1 : 0);
}
}
return TRUE;
}
/*
* MCU encoding for AC initial scan (either spectral selection,
* or first pass of successive approximation).
*/
METHODDEF(boolean)
encode_mcu_AC_first (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
{
arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
JBLOCKROW block;
unsigned char *st;
int tbl, k, ke;
int v, v2, m;
/* Emit restart marker if needed */
if (cinfo->restart_interval) {
if (entropy->restarts_to_go == 0) {
emit_restart(cinfo, entropy->next_restart_num);
entropy->restarts_to_go = cinfo->restart_interval;
entropy->next_restart_num++;
entropy->next_restart_num &= 7;
}
entropy->restarts_to_go--;
}
/* Encode the MCU data block */
block = MCU_data[0];
tbl = cinfo->cur_comp_info[0]->ac_tbl_no;
/* Sections F.1.4.2 & F.1.4.4.2: Encoding of AC coefficients */
/* Establish EOB (end-of-block) index */
for (ke = cinfo->Se; ke > 0; ke--)
/* We must apply the point transform by Al. For AC coefficients this
* is an integer division with rounding towards 0. To do this portably
* in C, we shift after obtaining the absolute value.
*/
if ((v = (*block)[jpeg_natural_order[ke]]) >= 0) {
if (v >>= cinfo->Al) break;
} else {
v = -v;
if (v >>= cinfo->Al) break;
}
/* Figure F.5: Encode_AC_Coefficients */
for (k = cinfo->Ss; k <= ke; k++) {
st = entropy->ac_stats[tbl] + 3 * (k - 1);
arith_encode(cinfo, st, 0); /* EOB decision */
for (;;) {
if ((v = (*block)[jpeg_natural_order[k]]) >= 0) {
if (v >>= cinfo->Al) {
arith_encode(cinfo, st + 1, 1);
arith_encode(cinfo, entropy->fixed_bin, 0);
break;
}
} else {
v = -v;
if (v >>= cinfo->Al) {
arith_encode(cinfo, st + 1, 1);
arith_encode(cinfo, entropy->fixed_bin, 1);
break;
}
}
arith_encode(cinfo, st + 1, 0); st += 3; k++;
}
st += 2;
/* Figure F.8: Encoding the magnitude category of v */
m = 0;
if (v -= 1) {
arith_encode(cinfo, st, 1);
m = 1;
v2 = v;
if (v2 >>= 1) {
arith_encode(cinfo, st, 1);
m <<= 1;
st = entropy->ac_stats[tbl] +
(k <= cinfo->arith_ac_K[tbl] ? 189 : 217);
while (v2 >>= 1) {
arith_encode(cinfo, st, 1);
m <<= 1;
st += 1;
}
}
}
arith_encode(cinfo, st, 0);
/* Figure F.9: Encoding the magnitude bit pattern of v */
st += 14;
while (m >>= 1)
arith_encode(cinfo, st, (m & v) ? 1 : 0);
}
/* Encode EOB decision only if k <= cinfo->Se */
if (k <= cinfo->Se) {
st = entropy->ac_stats[tbl] + 3 * (k - 1);
arith_encode(cinfo, st, 1);
}
return TRUE;
}
/*
* MCU encoding for DC successive approximation refinement scan.
*/
METHODDEF(boolean)
encode_mcu_DC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
{
arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
unsigned char *st;
int Al, blkn;
/* Emit restart marker if needed */
if (cinfo->restart_interval) {
if (entropy->restarts_to_go == 0) {
emit_restart(cinfo, entropy->next_restart_num);
entropy->restarts_to_go = cinfo->restart_interval;
entropy->next_restart_num++;
entropy->next_restart_num &= 7;
}
entropy->restarts_to_go--;
}
st = entropy->fixed_bin; /* use fixed probability estimation */
Al = cinfo->Al;
/* Encode the MCU data blocks */
for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
/* We simply emit the Al'th bit of the DC coefficient value. */
arith_encode(cinfo, st, (MCU_data[blkn][0][0] >> Al) & 1);
}
return TRUE;
}
/*
* MCU encoding for AC successive approximation refinement scan.
*/
METHODDEF(boolean)
encode_mcu_AC_refine (j_compress_ptr cinfo, JBLOCKROW *MCU_data)
{
arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
JBLOCKROW block;
unsigned char *st;
int tbl, k, ke, kex;
int v;
/* Emit restart marker if needed */
if (cinfo->restart_interval) {
if (entropy->restarts_to_go == 0) {
emit_restart(cinfo, entropy->next_restart_num);
entropy->restarts_to_go = cinfo->restart_interval;
entropy->next_restart_num++;
entropy->next_restart_num &= 7;
}
entropy->restarts_to_go--;
}
/* Encode the MCU data block */
block = MCU_data[0];
tbl = cinfo->cur_comp_info[0]->ac_tbl_no;
/* Section G.1.3.3: Encoding of AC coefficients */
/* Establish EOB (end-of-block) index */
for (ke = cinfo->Se; ke > 0; ke--)
/* We must apply the point transform by Al. For AC coefficients this
* is an integer division with rounding towards 0. To do this portably
* in C, we shift after obtaining the absolute value.
*/
if ((v = (*block)[jpeg_natural_order[ke]]) >= 0) {
if (v >>= cinfo->Al) break;
} else {
v = -v;
if (v >>= cinfo->Al) break;
}
/* Establish EOBx (previous stage end-of-block) index */
for (kex = ke; kex > 0; kex--)
if ((v = (*block)[jpeg_natural_order[kex]]) >= 0) {
if (v >>= cinfo->Ah) break;
} else {
v = -v;
if (v >>= cinfo->Ah) break;
}
/* Figure G.10: Encode_AC_Coefficients_SA */
for (k = cinfo->Ss; k <= ke; k++) {
st = entropy->ac_stats[tbl] + 3 * (k - 1);
if (k > kex)
arith_encode(cinfo, st, 0); /* EOB decision */
for (;;) {
if ((v = (*block)[jpeg_natural_order[k]]) >= 0) {
if (v >>= cinfo->Al) {
if (v >> 1) /* previously nonzero coef */
arith_encode(cinfo, st + 2, (v & 1));
else { /* newly nonzero coef */
arith_encode(cinfo, st + 1, 1);
arith_encode(cinfo, entropy->fixed_bin, 0);
}
break;
}
} else {
v = -v;
if (v >>= cinfo->Al) {
if (v >> 1) /* previously nonzero coef */
arith_encode(cinfo, st + 2, (v & 1));
else { /* newly nonzero coef */
arith_encode(cinfo, st + 1, 1);
arith_encode(cinfo, entropy->fixed_bin, 1);
}
break;
}
}
arith_encode(cinfo, st + 1, 0); st += 3; k++;
}
}
/* Encode EOB decision only if k <= cinfo->Se */
if (k <= cinfo->Se) {
st = entropy->ac_stats[tbl] + 3 * (k - 1);
arith_encode(cinfo, st, 1);
}
return TRUE;
}
/*
* Encode and output one MCU's worth of arithmetic-compressed coefficients.
*/
METHODDEF(boolean)
encode_mcu (j_compress_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, k, ke;
int v, v2, m;
/* Emit restart marker if needed */
if (cinfo->restart_interval) {
if (entropy->restarts_to_go == 0) {
emit_restart(cinfo, entropy->next_restart_num);
entropy->restarts_to_go = cinfo->restart_interval;
entropy->next_restart_num++;
entropy->next_restart_num &= 7;
}
entropy->restarts_to_go--;
}
/* Encode the MCU data blocks */
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.1.4.1 & F.1.4.4.1: Encoding 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.4: Encode_DC_DIFF */
if ((v = (*block)[0] - entropy->last_dc_val[ci]) == 0) {
arith_encode(cinfo, st, 0);
entropy->dc_context[ci] = 0; /* zero diff category */
} else {
entropy->last_dc_val[ci] = (*block)[0];
arith_encode(cinfo, st, 1);
/* Figure F.6: Encoding nonzero value v */
/* Figure F.7: Encoding the sign of v */
if (v > 0) {
arith_encode(cinfo, st + 1, 0); /* Table F.4: SS = S0 + 1 */
st += 2; /* Table F.4: SP = S0 + 2 */
entropy->dc_context[ci] = 4; /* small positive diff category */
} else {
v = -v;
arith_encode(cinfo, st + 1, 1); /* Table F.4: SS = S0 + 1 */
st += 3; /* Table F.4: SN = S0 + 3 */
entropy->dc_context[ci] = 8; /* small negative diff category */
}
/* Figure F.8: Encoding the magnitude category of v */
m = 0;
if (v -= 1) {
arith_encode(cinfo, st, 1);
m = 1;
v2 = v;
st = entropy->dc_stats[tbl] + 20; /* Table F.4: X1 = 20 */
while (v2 >>= 1) {
arith_encode(cinfo, st, 1);
m <<= 1;
st += 1;
}
}
arith_encode(cinfo, st, 0);
/* Section F.1.4.4.1.2: Establish dc_context conditioning category */
if (m < (int) ((1L << cinfo->arith_dc_L[tbl]) >> 1))
entropy->dc_context[ci] = 0; /* zero diff category */
else if (m > (int) ((1L << cinfo->arith_dc_U[tbl]) >> 1))
entropy->dc_context[ci] += 8; /* large diff category */
/* Figure F.9: Encoding the magnitude bit pattern of v */
st += 14;
while (m >>= 1)
arith_encode(cinfo, st, (m & v) ? 1 : 0);
}
/* Sections F.1.4.2 & F.1.4.4.2: Encoding of AC coefficients */
tbl = compptr->ac_tbl_no;
/* Establish EOB (end-of-block) index */
for (ke = DCTSIZE2 - 1; ke > 0; ke--)
if ((*block)[jpeg_natural_order[ke]]) break;
/* Figure F.5: Encode_AC_Coefficients */
for (k = 1; k <= ke; k++) {
st = entropy->ac_stats[tbl] + 3 * (k - 1);
arith_encode(cinfo, st, 0); /* EOB decision */
while ((v = (*block)[jpeg_natural_order[k]]) == 0) {
arith_encode(cinfo, st + 1, 0); st += 3; k++;
}
arith_encode(cinfo, st + 1, 1);
/* Figure F.6: Encoding nonzero value v */
/* Figure F.7: Encoding the sign of v */
if (v > 0) {
arith_encode(cinfo, entropy->fixed_bin, 0);
} else {
v = -v;
arith_encode(cinfo, entropy->fixed_bin, 1);
}
st += 2;
/* Figure F.8: Encoding the magnitude category of v */
m = 0;
if (v -= 1) {
arith_encode(cinfo, st, 1);
m = 1;
v2 = v;
if (v2 >>= 1) {
arith_encode(cinfo, st, 1);
m <<= 1;
st = entropy->ac_stats[tbl] +
(k <= cinfo->arith_ac_K[tbl] ? 189 : 217);
while (v2 >>= 1) {
arith_encode(cinfo, st, 1);
m <<= 1;
st += 1;
}
}
}
arith_encode(cinfo, st, 0);
/* Figure F.9: Encoding the magnitude bit pattern of v */
st += 14;
while (m >>= 1)
arith_encode(cinfo, st, (m & v) ? 1 : 0);
}
/* Encode EOB decision only if k <= DCTSIZE2 - 1 */
if (k <= DCTSIZE2 - 1) {
st = entropy->ac_stats[tbl] + 3 * (k - 1);
arith_encode(cinfo, st, 1);
}
}
return TRUE;
}
/*
* Initialize for an arithmetic-compressed scan.
*/
METHODDEF(void)
start_pass (j_compress_ptr cinfo, boolean gather_statistics)
{
arith_entropy_ptr entropy = (arith_entropy_ptr) cinfo->entropy;
int ci, tbl;
jpeg_component_info * compptr;
if (gather_statistics)
/* Make sure to avoid that in the master control logic!
* We are fully adaptive here and need no extra
* statistics gathering pass!
*/
ERREXIT(cinfo, JERR_NOT_COMPILED);
/* We assume jcmaster.c already validated the progressive scan parameters. */
/* Select execution routines */
if (cinfo->progressive_mode) {
if (cinfo->Ah == 0) {
if (cinfo->Ss == 0)
entropy->pub.encode_mcu = encode_mcu_DC_first;
else
entropy->pub.encode_mcu = encode_mcu_AC_first;
} else {
if (cinfo->Ss == 0)
entropy->pub.encode_mcu = encode_mcu_DC_refine;
else
entropy->pub.encode_mcu = encode_mcu_AC_refine;
}
} else
entropy->pub.encode_mcu = encode_mcu;
/* Allocate & initialize requested statistics areas */
for (ci = 0; ci < cinfo->comps_in_scan; ci++) {
compptr = cinfo->cur_comp_info[ci];
/* DC needs no table for refinement scan */
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;
}
/* AC needs no table when not present */
if (cinfo->progressive_mode == 0 || cinfo->Se) {
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);
#ifdef CALCULATE_SPECTRAL_CONDITIONING
if (cinfo->progressive_mode)
/* Section G.1.3.2: Set appropriate arithmetic conditioning value Kx */
cinfo->arith_ac_K[tbl] = cinfo->Ss + ((8 + cinfo->Se - cinfo->Ss) >> 4);
#endif
}
}
/* Initialize arithmetic encoding variables */
entropy->c = 0;
entropy->a = 0x10000L;
entropy->sc = 0;
entropy->zc = 0;
entropy->ct = 11;
entropy->buffer = -1; /* empty */
/* Initialize restart stuff */
entropy->restarts_to_go = cinfo->restart_interval;
entropy->next_restart_num = 0;
}
/*
* Module initialization routine for arithmetic entropy encoding.
*/
GLOBAL(void)
jinit_arith_encoder (j_compress_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_encoder));
cinfo->entropy = (struct jpeg_entropy_encoder *) entropy;
entropy->pub.start_pass = start_pass;
entropy->pub.finish_pass = finish_pass;
/* Mark tables unallocated */
for (i = 0; i < NUM_ARITH_TBLS; i++) {
entropy->dc_stats[i] = NULL;
entropy->ac_stats[i] = NULL;
}
/* Initialize index for fixed probability estimation */
entropy->fixed_bin[0] = 113;
}