mirror of
https://github.com/id-Software/DOOM-3-BFG.git
synced 2024-12-11 05:01:25 +00:00
671 lines
23 KiB
C++
671 lines
23 KiB
C++
|
/*
|
||
|
* jdphuff.c
|
||
|
*
|
||
|
* Copyright (C) 1995, 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 Huffman entropy decoding routines for progressive JPEG.
|
||
|
*
|
||
|
* Much of the complexity here has to do with supporting input suspension.
|
||
|
* If the data source module demands suspension, we want to be able to back
|
||
|
* up to the start of the current MCU. To do this, we copy state variables
|
||
|
* into local working storage, and update them back to the permanent
|
||
|
* storage only upon successful completion of an MCU.
|
||
|
*/
|
||
|
|
||
|
#define JPEG_INTERNALS
|
||
|
#include "jinclude.h"
|
||
|
#include "jpeglib.h"
|
||
|
#include "jdhuff.h" /* Declarations shared with jdhuff.c */
|
||
|
|
||
|
|
||
|
#ifdef D_PROGRESSIVE_SUPPORTED
|
||
|
|
||
|
/*
|
||
|
* Expanded entropy decoder object for progressive Huffman decoding.
|
||
|
*
|
||
|
* The savable_state subrecord contains fields that change within an MCU,
|
||
|
* but must not be updated permanently until we complete the MCU.
|
||
|
*/
|
||
|
|
||
|
typedef struct {
|
||
|
unsigned int EOBRUN; /* remaining EOBs in EOBRUN */
|
||
|
int last_dc_val[MAX_COMPS_IN_SCAN]; /* last DC coef for each component */
|
||
|
} savable_state;
|
||
|
|
||
|
/* This macro is to work around compilers with missing or broken
|
||
|
* structure assignment. You'll need to fix this code if you have
|
||
|
* such a compiler and you change MAX_COMPS_IN_SCAN.
|
||
|
*/
|
||
|
|
||
|
#ifndef NO_STRUCT_ASSIGN
|
||
|
#define ASSIGN_STATE( dest, src ) ( ( dest ) = ( src ) )
|
||
|
#else
|
||
|
#if MAX_COMPS_IN_SCAN == 4
|
||
|
#define ASSIGN_STATE( dest, src ) \
|
||
|
( ( dest ).EOBRUN = ( src ).EOBRUN, \
|
||
|
( dest ).last_dc_val[0] = ( src ).last_dc_val[0], \
|
||
|
( dest ).last_dc_val[1] = ( src ).last_dc_val[1], \
|
||
|
( dest ).last_dc_val[2] = ( src ).last_dc_val[2], \
|
||
|
( dest ).last_dc_val[3] = ( src ).last_dc_val[3] )
|
||
|
#endif
|
||
|
#endif
|
||
|
|
||
|
|
||
|
typedef struct {
|
||
|
struct jpeg_entropy_decoder pub;/* public fields */
|
||
|
|
||
|
/* These fields are loaded into local variables at start of each MCU.
|
||
|
* In case of suspension, we exit WITHOUT updating them.
|
||
|
*/
|
||
|
bitread_perm_state bitstate;/* Bit buffer at start of MCU */
|
||
|
savable_state saved; /* Other state at start of MCU */
|
||
|
|
||
|
/* These fields are NOT loaded into local working state. */
|
||
|
unsigned int restarts_to_go;/* MCUs left in this restart interval */
|
||
|
|
||
|
/* Pointers to derived tables (these workspaces have image lifespan) */
|
||
|
d_derived_tbl * derived_tbls[NUM_HUFF_TBLS];
|
||
|
|
||
|
d_derived_tbl * ac_derived_tbl;/* active table during an AC scan */
|
||
|
} phuff_entropy_decoder;
|
||
|
|
||
|
typedef phuff_entropy_decoder * phuff_entropy_ptr;
|
||
|
|
||
|
/* Forward declarations */
|
||
|
METHODDEF boolean decode_mcu_DC_first JPP( ( j_decompress_ptr cinfo,
|
||
|
JBLOCKROW * MCU_data ) );
|
||
|
METHODDEF boolean decode_mcu_AC_first JPP( ( j_decompress_ptr cinfo,
|
||
|
JBLOCKROW * MCU_data ) );
|
||
|
METHODDEF boolean decode_mcu_DC_refine JPP( ( j_decompress_ptr cinfo,
|
||
|
JBLOCKROW * MCU_data ) );
|
||
|
METHODDEF boolean decode_mcu_AC_refine JPP( ( j_decompress_ptr cinfo,
|
||
|
JBLOCKROW * MCU_data ) );
|
||
|
|
||
|
|
||
|
/*
|
||
|
* Initialize for a Huffman-compressed scan.
|
||
|
*/
|
||
|
|
||
|
METHODDEF void
|
||
|
start_pass_phuff_decoder( j_decompress_ptr cinfo ) {
|
||
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
||
|
boolean is_DC_band, bad;
|
||
|
int ci, coefi, tbl;
|
||
|
int * coef_bit_ptr;
|
||
|
jpeg_component_info * compptr;
|
||
|
|
||
|
is_DC_band = ( cinfo->Ss == 0 );
|
||
|
|
||
|
/* Validate scan parameters */
|
||
|
bad = FALSE;
|
||
|
if ( is_DC_band ) {
|
||
|
if ( cinfo->Se != 0 ) {
|
||
|
bad = TRUE;
|
||
|
}
|
||
|
} else {
|
||
|
/* need not check Ss/Se < 0 since they came from unsigned bytes */
|
||
|
if ( ( cinfo->Ss > cinfo->Se ) || ( cinfo->Se >= DCTSIZE2 ) ) {
|
||
|
bad = TRUE;
|
||
|
}
|
||
|
/* AC scans may have only one component */
|
||
|
if ( cinfo->comps_in_scan != 1 ) {
|
||
|
bad = TRUE;
|
||
|
}
|
||
|
}
|
||
|
if ( cinfo->Ah != 0 ) {
|
||
|
/* Successive approximation refinement scan: must have Al = Ah-1. */
|
||
|
if ( cinfo->Al != cinfo->Ah - 1 ) {
|
||
|
bad = TRUE;
|
||
|
}
|
||
|
}
|
||
|
if ( cinfo->Al > 13 ) { /* need not check for < 0 */
|
||
|
bad = TRUE;
|
||
|
}
|
||
|
if ( 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 cindex = cinfo->cur_comp_info[ci]->component_index;
|
||
|
coef_bit_ptr = &cinfo->coef_bits[cindex][0];
|
||
|
if ( ( !is_DC_band ) && ( 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 ( is_DC_band ) {
|
||
|
entropy->pub.decode_mcu = decode_mcu_DC_first;
|
||
|
} else {
|
||
|
entropy->pub.decode_mcu = decode_mcu_AC_first;
|
||
|
}
|
||
|
} else {
|
||
|
if ( is_DC_band ) {
|
||
|
entropy->pub.decode_mcu = decode_mcu_DC_refine;
|
||
|
} else {
|
||
|
entropy->pub.decode_mcu = decode_mcu_AC_refine;
|
||
|
}
|
||
|
}
|
||
|
|
||
|
for ( ci = 0; ci < cinfo->comps_in_scan; ci++ ) {
|
||
|
compptr = cinfo->cur_comp_info[ci];
|
||
|
/* Make sure requested tables are present, and compute derived tables.
|
||
|
* We may build same derived table more than once, but it's not expensive.
|
||
|
*/
|
||
|
if ( is_DC_band ) {
|
||
|
if ( cinfo->Ah == 0 ) {/* DC refinement needs no table */
|
||
|
tbl = compptr->dc_tbl_no;
|
||
|
if ( ( tbl < 0 ) || ( tbl >= NUM_HUFF_TBLS ) ||
|
||
|
( cinfo->dc_huff_tbl_ptrs[tbl] == NULL ) ) {
|
||
|
ERREXIT1( cinfo, JERR_NO_HUFF_TABLE, tbl );
|
||
|
}
|
||
|
jpeg_make_d_derived_tbl( cinfo, cinfo->dc_huff_tbl_ptrs[tbl],
|
||
|
&entropy->derived_tbls[tbl] );
|
||
|
}
|
||
|
} else {
|
||
|
tbl = compptr->ac_tbl_no;
|
||
|
if ( ( tbl < 0 ) || ( tbl >= NUM_HUFF_TBLS ) ||
|
||
|
( cinfo->ac_huff_tbl_ptrs[tbl] == NULL ) ) {
|
||
|
ERREXIT1( cinfo, JERR_NO_HUFF_TABLE, tbl );
|
||
|
}
|
||
|
jpeg_make_d_derived_tbl( cinfo, cinfo->ac_huff_tbl_ptrs[tbl],
|
||
|
&entropy->derived_tbls[tbl] );
|
||
|
/* remember the single active table */
|
||
|
entropy->ac_derived_tbl = entropy->derived_tbls[tbl];
|
||
|
}
|
||
|
/* Initialize DC predictions to 0 */
|
||
|
entropy->saved.last_dc_val[ci] = 0;
|
||
|
}
|
||
|
|
||
|
/* Initialize bitread state variables */
|
||
|
entropy->bitstate.bits_left = 0;
|
||
|
entropy->bitstate.get_buffer = 0;/* unnecessary, but keeps Purify quiet */
|
||
|
entropy->bitstate.printed_eod = FALSE;
|
||
|
|
||
|
/* Initialize private state variables */
|
||
|
entropy->saved.EOBRUN = 0;
|
||
|
|
||
|
/* Initialize restart counter */
|
||
|
entropy->restarts_to_go = cinfo->restart_interval;
|
||
|
}
|
||
|
|
||
|
|
||
|
/*
|
||
|
* Figure F.12: extend sign bit.
|
||
|
* On some machines, a shift and add will be faster than a table lookup.
|
||
|
*/
|
||
|
|
||
|
#ifdef AVOID_TABLES
|
||
|
|
||
|
#define HUFF_EXTEND( x, s ) ( ( x ) < ( 1 << ( ( s ) - 1 ) ) ? ( x ) + ( ( ( -1 ) << ( s ) ) + 1 ) : ( x ) )
|
||
|
|
||
|
#else
|
||
|
|
||
|
#define HUFF_EXTEND( x, s ) ( ( x ) < extend_test[s] ? ( x ) + extend_offset[s] : ( x ) )
|
||
|
|
||
|
static const int extend_test[16] = /* entry n is 2**(n-1) */
|
||
|
{ 0, 0x0001, 0x0002, 0x0004, 0x0008, 0x0010, 0x0020, 0x0040, 0x0080,
|
||
|
0x0100, 0x0200, 0x0400, 0x0800, 0x1000, 0x2000, 0x4000 };
|
||
|
|
||
|
static const int extend_offset[16] = /* entry n is (-1 << n) + 1 */
|
||
|
{ 0, ( ( -1 ) << 1 ) + 1, ( ( -1 ) << 2 ) + 1, ( ( -1 ) << 3 ) + 1, ( ( -1 ) << 4 ) + 1,
|
||
|
( ( -1 ) << 5 ) + 1, ( ( -1 ) << 6 ) + 1, ( ( -1 ) << 7 ) + 1, ( ( -1 ) << 8 ) + 1,
|
||
|
( ( -1 ) << 9 ) + 1, ( ( -1 ) << 10 ) + 1, ( ( -1 ) << 11 ) + 1, ( ( -1 ) << 12 ) + 1,
|
||
|
( ( -1 ) << 13 ) + 1, ( ( -1 ) << 14 ) + 1, ( ( -1 ) << 15 ) + 1 };
|
||
|
|
||
|
#endif /* AVOID_TABLES */
|
||
|
|
||
|
|
||
|
/*
|
||
|
* Check for a restart marker & resynchronize decoder.
|
||
|
* Returns FALSE if must suspend.
|
||
|
*/
|
||
|
|
||
|
LOCAL boolean
|
||
|
process_restart( j_decompress_ptr cinfo ) {
|
||
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
||
|
int ci;
|
||
|
|
||
|
/* Throw away any unused bits remaining in bit buffer; */
|
||
|
/* include any full bytes in next_marker's count of discarded bytes */
|
||
|
cinfo->marker->discarded_bytes += entropy->bitstate.bits_left / 8;
|
||
|
entropy->bitstate.bits_left = 0;
|
||
|
|
||
|
/* Advance past the RSTn marker */
|
||
|
if ( !( *cinfo->marker->read_restart_marker )( cinfo ) ) {
|
||
|
return FALSE;
|
||
|
}
|
||
|
|
||
|
/* Re-initialize DC predictions to 0 */
|
||
|
for ( ci = 0; ci < cinfo->comps_in_scan; ci++ ) {
|
||
|
entropy->saved.last_dc_val[ci] = 0;
|
||
|
}
|
||
|
/* Re-init EOB run count, too */
|
||
|
entropy->saved.EOBRUN = 0;
|
||
|
|
||
|
/* Reset restart counter */
|
||
|
entropy->restarts_to_go = cinfo->restart_interval;
|
||
|
|
||
|
/* Next segment can get another out-of-data warning */
|
||
|
entropy->bitstate.printed_eod = FALSE;
|
||
|
|
||
|
return TRUE;
|
||
|
}
|
||
|
|
||
|
|
||
|
/*
|
||
|
* Huffman MCU decoding.
|
||
|
* Each of these routines decodes and returns one MCU's worth of
|
||
|
* Huffman-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.
|
||
|
*
|
||
|
* We return FALSE if data source requested suspension. In that case no
|
||
|
* changes have been made to permanent state. (Exception: some output
|
||
|
* coefficients may already have been assigned. This is harmless for
|
||
|
* spectral selection, since we'll just re-assign them on the next call.
|
||
|
* Successive approximation AC refinement has to be more careful, however.)
|
||
|
*/
|
||
|
|
||
|
/*
|
||
|
* 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 ) {
|
||
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
||
|
int Al = cinfo->Al;
|
||
|
register int s, r;
|
||
|
int blkn, ci;
|
||
|
JBLOCKROW block;
|
||
|
BITREAD_STATE_VARS;
|
||
|
savable_state state;
|
||
|
d_derived_tbl * tbl;
|
||
|
jpeg_component_info * compptr;
|
||
|
|
||
|
/* Process restart marker if needed; may have to suspend */
|
||
|
if ( cinfo->restart_interval ) {
|
||
|
if ( entropy->restarts_to_go == 0 ) {
|
||
|
if ( !process_restart( cinfo ) ) {
|
||
|
return FALSE;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* Load up working state */
|
||
|
BITREAD_LOAD_STATE( cinfo, entropy->bitstate );
|
||
|
ASSIGN_STATE( state, entropy->saved );
|
||
|
|
||
|
/* 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];
|
||
|
tbl = entropy->derived_tbls[compptr->dc_tbl_no];
|
||
|
|
||
|
/* Decode a single block's worth of coefficients */
|
||
|
|
||
|
/* Section F.2.2.1: decode the DC coefficient difference */
|
||
|
HUFF_DECODE( s, br_state, tbl, return FALSE, label1 );
|
||
|
if ( s ) {
|
||
|
CHECK_BIT_BUFFER( br_state, s, return FALSE );
|
||
|
|
||
|
r = GET_BITS( s );
|
||
|
s = HUFF_EXTEND( r, s );
|
||
|
}
|
||
|
|
||
|
/* Convert DC difference to actual value, update last_dc_val */
|
||
|
s += state.last_dc_val[ci];
|
||
|
state.last_dc_val[ci] = s;
|
||
|
/* Scale and output the DC coefficient (assumes jpeg_natural_order[0]=0) */
|
||
|
( *block )[0] = (JCOEF) ( s << Al );
|
||
|
}
|
||
|
|
||
|
/* Completed MCU, so update state */
|
||
|
BITREAD_SAVE_STATE( cinfo, entropy->bitstate );
|
||
|
ASSIGN_STATE( entropy->saved, state );
|
||
|
|
||
|
/* Account for restart interval (no-op if not using restarts) */
|
||
|
entropy->restarts_to_go--;
|
||
|
|
||
|
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 ) {
|
||
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
||
|
int Se = cinfo->Se;
|
||
|
int Al = cinfo->Al;
|
||
|
register int s, k, r;
|
||
|
unsigned int EOBRUN;
|
||
|
JBLOCKROW block;
|
||
|
BITREAD_STATE_VARS;
|
||
|
d_derived_tbl * tbl;
|
||
|
|
||
|
/* Process restart marker if needed; may have to suspend */
|
||
|
if ( cinfo->restart_interval ) {
|
||
|
if ( entropy->restarts_to_go == 0 ) {
|
||
|
if ( !process_restart( cinfo ) ) {
|
||
|
return FALSE;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* Load up working state.
|
||
|
* We can avoid loading/saving bitread state if in an EOB run.
|
||
|
*/
|
||
|
EOBRUN = entropy->saved.EOBRUN;/* only part of saved state we care about */
|
||
|
|
||
|
/* There is always only one block per MCU */
|
||
|
|
||
|
if ( EOBRUN > 0 ) { /* if it's a band of zeroes... */
|
||
|
EOBRUN--;
|
||
|
} /* ...process it now (we do nothing) */
|
||
|
else {
|
||
|
BITREAD_LOAD_STATE( cinfo, entropy->bitstate );
|
||
|
block = MCU_data[0];
|
||
|
tbl = entropy->ac_derived_tbl;
|
||
|
|
||
|
for ( k = cinfo->Ss; k <= Se; k++ ) {
|
||
|
HUFF_DECODE( s, br_state, tbl, return FALSE, label2 );
|
||
|
r = s >> 4;
|
||
|
s &= 15;
|
||
|
if ( s ) {
|
||
|
k += r;
|
||
|
|
||
|
CHECK_BIT_BUFFER( br_state, s, return FALSE );
|
||
|
r = GET_BITS( s );
|
||
|
s = HUFF_EXTEND( r, s );
|
||
|
/* Scale and output coefficient in natural (dezigzagged) order */
|
||
|
( *block )[jpeg_natural_order[k]] = (JCOEF) ( s << Al );
|
||
|
} else {
|
||
|
if ( r == 15 ) {/* ZRL */
|
||
|
k += 15;/* skip 15 zeroes in band */
|
||
|
} else {/* EOBr, run length is 2^r + appended bits */
|
||
|
EOBRUN = 1 << r;
|
||
|
if ( r ) {/* EOBr, r > 0 */
|
||
|
CHECK_BIT_BUFFER( br_state, r, return FALSE );
|
||
|
r = GET_BITS( r );
|
||
|
EOBRUN += r;
|
||
|
}
|
||
|
EOBRUN--; /* this band is processed at this moment */
|
||
|
break; /* force end-of-band */
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
BITREAD_SAVE_STATE( cinfo, entropy->bitstate );
|
||
|
}
|
||
|
|
||
|
/* Completed MCU, so update state */
|
||
|
entropy->saved.EOBRUN = EOBRUN;/* only part of saved state we care about */
|
||
|
|
||
|
/* Account for restart interval (no-op if not using restarts) */
|
||
|
entropy->restarts_to_go--;
|
||
|
|
||
|
return TRUE;
|
||
|
}
|
||
|
|
||
|
|
||
|
/*
|
||
|
* MCU decoding for DC successive approximation refinement scan.
|
||
|
* Note: we assume such scans can be multi-component, although the spec
|
||
|
* is not very clear on the point.
|
||
|
*/
|
||
|
|
||
|
METHODDEF boolean
|
||
|
decode_mcu_DC_refine( j_decompress_ptr cinfo, JBLOCKROW * MCU_data ) {
|
||
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
||
|
int p1 = 1 << cinfo->Al;/* 1 in the bit position being coded */
|
||
|
int blkn;
|
||
|
JBLOCKROW block;
|
||
|
BITREAD_STATE_VARS;
|
||
|
|
||
|
/* Process restart marker if needed; may have to suspend */
|
||
|
if ( cinfo->restart_interval ) {
|
||
|
if ( entropy->restarts_to_go == 0 ) {
|
||
|
if ( !process_restart( cinfo ) ) {
|
||
|
return FALSE;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* Load up working state */
|
||
|
BITREAD_LOAD_STATE( cinfo, entropy->bitstate );
|
||
|
|
||
|
/* Outer loop handles each block in the MCU */
|
||
|
|
||
|
for ( blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++ ) {
|
||
|
block = MCU_data[blkn];
|
||
|
|
||
|
/* Encoded data is simply the next bit of the two's-complement DC value */
|
||
|
CHECK_BIT_BUFFER( br_state, 1, return FALSE );
|
||
|
if ( GET_BITS( 1 ) ) {
|
||
|
( *block )[0] |= p1;
|
||
|
}
|
||
|
/* Note: since we use |=, repeating the assignment later is safe */
|
||
|
}
|
||
|
|
||
|
/* Completed MCU, so update state */
|
||
|
BITREAD_SAVE_STATE( cinfo, entropy->bitstate );
|
||
|
|
||
|
/* Account for restart interval (no-op if not using restarts) */
|
||
|
entropy->restarts_to_go--;
|
||
|
|
||
|
return TRUE;
|
||
|
}
|
||
|
|
||
|
|
||
|
/*
|
||
|
* MCU decoding for AC successive approximation refinement scan.
|
||
|
*/
|
||
|
|
||
|
METHODDEF boolean
|
||
|
decode_mcu_AC_refine( j_decompress_ptr cinfo, JBLOCKROW * MCU_data ) {
|
||
|
phuff_entropy_ptr entropy = (phuff_entropy_ptr) cinfo->entropy;
|
||
|
int Se = cinfo->Se;
|
||
|
int p1 = 1 << cinfo->Al;/* 1 in the bit position being coded */
|
||
|
int m1 = ( -1 ) << cinfo->Al;/* -1 in the bit position being coded */
|
||
|
register int s, k, r;
|
||
|
unsigned int EOBRUN;
|
||
|
JBLOCKROW block;
|
||
|
JCOEFPTR thiscoef;
|
||
|
BITREAD_STATE_VARS;
|
||
|
d_derived_tbl * tbl;
|
||
|
int num_newnz;
|
||
|
int newnz_pos[DCTSIZE2];
|
||
|
|
||
|
/* Process restart marker if needed; may have to suspend */
|
||
|
if ( cinfo->restart_interval ) {
|
||
|
if ( entropy->restarts_to_go == 0 ) {
|
||
|
if ( !process_restart( cinfo ) ) {
|
||
|
return FALSE;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/* Load up working state */
|
||
|
BITREAD_LOAD_STATE( cinfo, entropy->bitstate );
|
||
|
EOBRUN = entropy->saved.EOBRUN;/* only part of saved state we care about */
|
||
|
|
||
|
/* There is always only one block per MCU */
|
||
|
block = MCU_data[0];
|
||
|
tbl = entropy->ac_derived_tbl;
|
||
|
|
||
|
/* If we are forced to suspend, we must undo the assignments to any newly
|
||
|
* nonzero coefficients in the block, because otherwise we'd get confused
|
||
|
* next time about which coefficients were already nonzero.
|
||
|
* But we need not undo addition of bits to already-nonzero coefficients;
|
||
|
* instead, we can test the current bit position to see if we already did it.
|
||
|
*/
|
||
|
num_newnz = 0;
|
||
|
|
||
|
/* initialize coefficient loop counter to start of band */
|
||
|
k = cinfo->Ss;
|
||
|
|
||
|
if ( EOBRUN == 0 ) {
|
||
|
for (; k <= Se; k++ ) {
|
||
|
HUFF_DECODE( s, br_state, tbl, goto undoit, label3 );
|
||
|
r = s >> 4;
|
||
|
s &= 15;
|
||
|
if ( s ) {
|
||
|
if ( s != 1 ) {/* size of new coef should always be 1 */
|
||
|
WARNMS( cinfo, JWRN_HUFF_BAD_CODE );
|
||
|
}
|
||
|
CHECK_BIT_BUFFER( br_state, 1, goto undoit );
|
||
|
if ( GET_BITS( 1 ) ) {
|
||
|
s = p1;
|
||
|
} /* newly nonzero coef is positive */
|
||
|
else {
|
||
|
s = m1;
|
||
|
} /* newly nonzero coef is negative */
|
||
|
} else {
|
||
|
if ( r != 15 ) {
|
||
|
EOBRUN = 1 << r;/* EOBr, run length is 2^r + appended bits */
|
||
|
if ( r ) {
|
||
|
CHECK_BIT_BUFFER( br_state, r, goto undoit );
|
||
|
r = GET_BITS( r );
|
||
|
EOBRUN += r;
|
||
|
}
|
||
|
break; /* rest of block is handled by EOB logic */
|
||
|
}
|
||
|
/* note s = 0 for processing ZRL */
|
||
|
}
|
||
|
/* Advance over already-nonzero coefs and r still-zero coefs,
|
||
|
* appending correction bits to the nonzeroes. A correction bit is 1
|
||
|
* if the absolute value of the coefficient must be increased.
|
||
|
*/
|
||
|
do {
|
||
|
thiscoef = *block + jpeg_natural_order[k];
|
||
|
if ( *thiscoef != 0 ) {
|
||
|
CHECK_BIT_BUFFER( br_state, 1, goto undoit );
|
||
|
if ( GET_BITS( 1 ) ) {
|
||
|
if ( ( *thiscoef & p1 ) == 0 ) {/* do nothing if already changed it */
|
||
|
if ( *thiscoef >= 0 ) {
|
||
|
*thiscoef += p1;
|
||
|
} else {
|
||
|
*thiscoef += m1;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
} else {
|
||
|
if ( --r < 0 ) {
|
||
|
break;
|
||
|
} /* reached target zero coefficient */
|
||
|
}
|
||
|
k++;
|
||
|
} while ( k <= Se );
|
||
|
if ( s ) {
|
||
|
int pos = jpeg_natural_order[k];
|
||
|
/* Output newly nonzero coefficient */
|
||
|
( *block )[pos] = (JCOEF) s;
|
||
|
/* Remember its position in case we have to suspend */
|
||
|
newnz_pos[num_newnz++] = pos;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if ( EOBRUN > 0 ) {
|
||
|
/* Scan any remaining coefficient positions after the end-of-band
|
||
|
* (the last newly nonzero coefficient, if any). Append a correction
|
||
|
* bit to each already-nonzero coefficient. A correction bit is 1
|
||
|
* if the absolute value of the coefficient must be increased.
|
||
|
*/
|
||
|
for (; k <= Se; k++ ) {
|
||
|
thiscoef = *block + jpeg_natural_order[k];
|
||
|
if ( *thiscoef != 0 ) {
|
||
|
CHECK_BIT_BUFFER( br_state, 1, goto undoit );
|
||
|
if ( GET_BITS( 1 ) ) {
|
||
|
if ( ( *thiscoef & p1 ) == 0 ) {/* do nothing if already changed it */
|
||
|
if ( *thiscoef >= 0 ) {
|
||
|
*thiscoef += p1;
|
||
|
} else {
|
||
|
*thiscoef += m1;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
/* Count one block completed in EOB run */
|
||
|
EOBRUN--;
|
||
|
}
|
||
|
|
||
|
/* Completed MCU, so update state */
|
||
|
BITREAD_SAVE_STATE( cinfo, entropy->bitstate );
|
||
|
entropy->saved.EOBRUN = EOBRUN;/* only part of saved state we care about */
|
||
|
|
||
|
/* Account for restart interval (no-op if not using restarts) */
|
||
|
entropy->restarts_to_go--;
|
||
|
|
||
|
return TRUE;
|
||
|
|
||
|
undoit:
|
||
|
/* Re-zero any output coefficients that we made newly nonzero */
|
||
|
while ( num_newnz > 0 ) {
|
||
|
( *block )[newnz_pos[--num_newnz]] = 0;
|
||
|
}
|
||
|
|
||
|
return FALSE;
|
||
|
}
|
||
|
|
||
|
|
||
|
/*
|
||
|
* Module initialization routine for progressive Huffman entropy decoding.
|
||
|
*/
|
||
|
|
||
|
GLOBAL void
|
||
|
jinit_phuff_decoder( j_decompress_ptr cinfo ) {
|
||
|
phuff_entropy_ptr entropy;
|
||
|
int * coef_bit_ptr;
|
||
|
int ci, i;
|
||
|
|
||
|
entropy = (phuff_entropy_ptr)
|
||
|
( *cinfo->mem->alloc_small )( (j_common_ptr) cinfo, JPOOL_IMAGE,
|
||
|
SIZEOF( phuff_entropy_decoder ) );
|
||
|
cinfo->entropy = (struct jpeg_entropy_decoder *) entropy;
|
||
|
entropy->pub.start_pass = start_pass_phuff_decoder;
|
||
|
|
||
|
/* Mark derived tables unallocated */
|
||
|
for ( i = 0; i < NUM_HUFF_TBLS; i++ ) {
|
||
|
entropy->derived_tbls[i] = NULL;
|
||
|
}
|
||
|
|
||
|
/* Create progression status table */
|
||
|
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;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
#endif /* D_PROGRESSIVE_SUPPORTED */
|