ryan/mozjpeg
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

The Independent JPEG Group's JPEG software v8

Browse Source
This commit is contained in:
Guido Vollbeding
2010-01-10 00:00:00 +00:00
committed by DRC
parent 5996a25e2f
commit 989630f70c
41 changed files with 3910 additions and 5168 deletions
Download Patch File Download Diff File Expand all files Collapse all files

82
jdarith.c
View File

@@ -1,7 +1,7 @@
/*
* jdarith.c
*
* Developed 1997 by Guido Vollbeding.
* 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.
*
@@ -37,6 +37,9 @@ typedef struct {
/* 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_decoder;
typedef arith_entropy_decoder * arith_entropy_ptr;
@@ -45,8 +48,6 @@ typedef arith_entropy_decoder * arith_entropy_ptr;
* 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.
@@ -104,7 +105,6 @@ get_byte (j_decompress_ptr cinfo)
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;
@@ -149,7 +149,7 @@ arith_decode (j_decompress_ptr cinfo, unsigned char *st)
* Qe values and probability estimation state machine
*/
sv = *st;
qe = jaritab[sv & 0x7F]; /* => Qe_Value */
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 */
@@ -197,16 +197,17 @@ process_restart (j_decompress_ptr cinfo)
if (! (*cinfo->marker->read_restart_marker) (cinfo))
ERREXIT(cinfo, JERR_CANT_SUSPEND);
/* Re-initialize statistics areas */
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)) {
if (! cinfo->progressive_mode || (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) {
if ((! cinfo->progressive_mode && cinfo->lim_Se) ||
(cinfo->progressive_mode && cinfo->Ss)) {
MEMZERO(entropy->ac_stats[compptr->ac_tbl_no], AC_STAT_BINS);
}
}
@@ -288,9 +289,9 @@ decode_mcu_DC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
}
}
/* Section F.1.4.4.1.2: Establish dc_context conditioning category */
if (m < (int) (((INT32) 1 << cinfo->arith_dc_L[tbl]) >> 1))
if (m < (int) ((1L << 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))
else if (m > (int) ((1L << 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 */
@@ -324,6 +325,7 @@ decode_mcu_AC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
unsigned char *st;
int tbl, sign, k;
int v, m;
const int * natural_order;
/* Process restart marker if needed */
if (cinfo->restart_interval) {
@@ -334,6 +336,8 @@ decode_mcu_AC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
if (entropy->ct == -1) return TRUE; /* if error do nothing */
natural_order = cinfo->natural_order;
/* There is always only one block per MCU */
block = MCU_data[0];
tbl = cinfo->cur_comp_info[0]->ac_tbl_no;
@@ -354,8 +358,7 @@ decode_mcu_AC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
}
/* 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);
sign = arith_decode(cinfo, entropy->fixed_bin);
st += 2;
/* Figure F.23: Decoding the magnitude category of v */
if ((m = arith_decode(cinfo, st)) != 0) {
@@ -380,7 +383,7 @@ decode_mcu_AC_first (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
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);
(*block)[natural_order[k]] = (JCOEF) (v << cinfo->Al);
}
return TRUE;
@@ -395,7 +398,7 @@ 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];
unsigned char *st;
int p1, blkn;
/* Process restart marker if needed */
@@ -405,12 +408,12 @@ decode_mcu_DC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
entropy->restarts_to_go--;
}
st = entropy->fixed_bin; /* use fixed probability estimation */
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;
@@ -433,6 +436,7 @@ decode_mcu_AC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
unsigned char *st;
int tbl, k, kex;
int p1, m1;
const int * natural_order;
/* Process restart marker if needed */
if (cinfo->restart_interval) {
@@ -443,6 +447,8 @@ decode_mcu_AC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
if (entropy->ct == -1) return TRUE; /* if error do nothing */
natural_order = cinfo->natural_order;
/* There is always only one block per MCU */
block = MCU_data[0];
tbl = cinfo->cur_comp_info[0]->ac_tbl_no;
@@ -451,15 +457,15 @@ decode_mcu_AC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
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 (kex = cinfo->Se; kex > 0; kex--)
if ((*block)[natural_order[kex]]) break;
for (k = cinfo->Ss; k <= cinfo->Se; k++) {
st = entropy->ac_stats[tbl] + 3 * (k - 1);
if (k >= kex)
if (k > kex)
if (arith_decode(cinfo, st)) break; /* EOB flag */
for (;;) {
thiscoef = *block + jpeg_natural_order[k];
thiscoef = *block + natural_order[k];
if (*thiscoef) { /* previously nonzero coef */
if (arith_decode(cinfo, st + 2)) {
if (*thiscoef < 0)
@@ -470,8 +476,7 @@ decode_mcu_AC_refine (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
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))
if (arith_decode(cinfo, entropy->fixed_bin))
*thiscoef = m1;
else
*thiscoef = p1;
@@ -503,6 +508,7 @@ decode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
unsigned char *st;
int blkn, ci, tbl, sign, k;
int v, m;
const int * natural_order;
/* Process restart marker if needed */
if (cinfo->restart_interval) {
@@ -513,6 +519,8 @@ decode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
if (entropy->ct == -1) return TRUE; /* if error do nothing */
natural_order = cinfo->natural_order;
/* Outer loop handles each block in the MCU */
for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {
@@ -548,9 +556,9 @@ decode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
}
}
/* Section F.1.4.4.1.2: Establish dc_context conditioning category */
if (m < (int) (((INT32) 1 << cinfo->arith_dc_L[tbl]) >> 1))
if (m < (int) ((1L << 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))
else if (m > (int) ((1L << 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 */
@@ -570,12 +578,12 @@ decode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
tbl = compptr->ac_tbl_no;
/* Figure F.20: Decode_AC_coefficients */
for (k = 1; k < DCTSIZE2; k++) {
for (k = 1; k <= cinfo->lim_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 >= DCTSIZE2) {
if (k > cinfo->lim_Se) {
WARNMS(cinfo, JWRN_ARITH_BAD_CODE);
entropy->ct = -1; /* spectral overflow */
return TRUE;
@@ -583,8 +591,7 @@ decode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
}
/* 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);
sign = arith_decode(cinfo, entropy->fixed_bin);
st += 2;
/* Figure F.23: Decoding the magnitude category of v */
if ((m = arith_decode(cinfo, st)) != 0) {
@@ -608,7 +615,7 @@ decode_mcu (j_decompress_ptr cinfo, JBLOCKROW *MCU_data)
while (m >>= 1)
if (arith_decode(cinfo, st)) v |= m;
v += 1; if (sign) v = -v;
(*block)[jpeg_natural_order[k]] = (JCOEF) v;
(*block)[natural_order[k]] = (JCOEF) v;
}
}
@@ -634,7 +641,7 @@ start_pass (j_decompress_ptr cinfo)
goto bad;
} else {
/* need not check Ss/Se < 0 since they came from unsigned bytes */
if (cinfo->Se < cinfo->Ss || cinfo->Se >= DCTSIZE2)
if (cinfo->Se < cinfo->Ss || cinfo->Se > cinfo->lim_Se)
goto bad;
/* AC scans may have only one component */
if (cinfo->comps_in_scan != 1)
@@ -680,20 +687,19 @@ start_pass (j_decompress_ptr cinfo)
}
} 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.
* This ought to be an error condition, but we make it a warning.
*/
if (cinfo->Ss != 0 || cinfo->Se != DCTSIZE2-1 ||
cinfo->Ah != 0 || cinfo->Al != 0)
if (cinfo->Ss != 0 || cinfo->Ah != 0 || cinfo->Al != 0 ||
(cinfo->Se < DCTSIZE2 && cinfo->Se != cinfo->lim_Se))
WARNMS(cinfo, JWRN_NOT_SEQUENTIAL);
/* Select MCU decoding routine */
entropy->pub.decode_mcu = decode_mcu;
}
/* Allocate & initialize requested statistics areas */
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)) {
if (! cinfo->progressive_mode || (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);
@@ -705,7 +711,8 @@ start_pass (j_decompress_ptr cinfo)
entropy->last_dc_val[ci] = 0;
entropy->dc_context[ci] = 0;
}
if (cinfo->progressive_mode == 0 || cinfo->Ss) {
if ((! cinfo->progressive_mode && cinfo->lim_Se) ||
(cinfo->progressive_mode && cinfo->Ss)) {
tbl = compptr->ac_tbl_no;
if (tbl < 0 || tbl >= NUM_ARITH_TBLS)
ERREXIT1(cinfo, JERR_NO_ARITH_TABLE, tbl);
@@ -748,6 +755,9 @@ jinit_arith_decoder (j_decompress_ptr cinfo)
entropy->ac_stats[i] = NULL;
}
/* Initialize index for fixed probability estimation */
entropy->fixed_bin[0] = 113;
if (cinfo->progressive_mode) {
/* Create progression status table */
int *coef_bit_ptr, ci;