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jcphuff.cs
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jcphuff.cs
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#if C_PROGRESSIVE_SUPPORTED
// jcphuff.cs
//
// Based on libjpeg version 6b - 27-Mar-1998
// Copyright (C) 2007-2008 by the Authors
// Copyright (C) 1995-1998, Thomas G. Lane.
// For conditions of distribution and use, see the accompanying License.txt file.
//
// This file contains Huffman entropy encoding routines for progressive JPEG.
//
// We do not support output suspension in this module, since the library
// currently does not allow multiple-scan files to be written with output
// suspension.
namespace Free.Ports.LibJpeg
{
public static partial class libjpeg
{
// Expanded entropy encoder object for progressive Huffman encoding.
class phuff_entropy_encoder
{
// Mode flag: true for optimization, false for actual data output
public bool gather_statistics;
// Bit-level coding status.
// next_output_byte/free_in_buffer are local copies of cinfo.dest fields.
public byte[] output_bytes;
public int next_output_byte; // => next byte to write in buffer
public uint free_in_buffer; // # of byte spaces remaining in buffer
public int put_buffer; // current bit-accumulation buffer
public int put_bits; // # of bits now in it
public jpeg_compress cinfo; // link to cinfo (needed for dump_buffer)
// Coding status for DC components
public int[] last_dc_val=new int[MAX_COMPS_IN_SCAN]; // last DC coef for each component
// Coding status for AC components
public int ac_tbl_no; // the table number of the single component
public uint EOBRUN; // run length of EOBs
public uint BE; // # of buffered correction bits before MCU
public byte[] bit_buffer; // buffer for correction bits (1 per char)
// packing correction bits tightly would save some space but cost time...
public uint restarts_to_go; // MCUs left in this restart interval
public int next_restart_num; // next restart number to write (0-7)
// Pointers to derived tables (these workspaces have image lifespan).
// Since any one scan codes only DC or only AC, we only need one set
// of tables, not one for DC and one for AC.
public c_derived_tbl[] derived_tbls=new c_derived_tbl[NUM_HUFF_TBLS];
// Statistics tables for optimization; again, one set is enough
public int[][] count_ptrs=new int[NUM_HUFF_TBLS][];
}
// MAX_CORR_BITS is the number of bits the AC refinement correction-bit
// buffer can hold. Larger sizes may slightly improve compression, but
// 1000 is already well into the realm of overkill.
// The minimum safe size is 64 bits.
const int MAX_CORR_BITS=1000; // Max # of correction bits I can buffer
// Initialize for a Huffman-compressed scan using progressive JPEG.
static void start_pass_phuff(jpeg_compress cinfo, bool gather_statistics)
{
jpeg_lossy_c_codec lossyc=(jpeg_lossy_c_codec)cinfo.coef;
phuff_entropy_encoder entropy=(phuff_entropy_encoder)lossyc.entropy_private;
entropy.cinfo=cinfo;
entropy.gather_statistics=gather_statistics;
bool is_DC_band=(cinfo.Ss==0);
// We assume jcmaster.cs already validated the scan parameters.
// Select execution routines
if(cinfo.Ah==0)
{
if(is_DC_band) lossyc.entropy_encode_mcu=encode_mcu_DC_first_phuff;
else lossyc.entropy_encode_mcu=encode_mcu_AC_first_phuff;
}
else
{
if(is_DC_band) lossyc.entropy_encode_mcu=encode_mcu_DC_refine_phuff;
else
{
lossyc.entropy_encode_mcu=encode_mcu_AC_refine_phuff;
// AC refinement needs a correction bit buffer
if(entropy.bit_buffer==null)
{
try
{
entropy.bit_buffer=new byte[MAX_CORR_BITS];
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
}
}
}
if(gather_statistics) lossyc.entropy_finish_pass=finish_pass_gather_phuff;
else lossyc.entropy_finish_pass=finish_pass_phuff;
// Only DC coefficients may be interleaved, so cinfo.comps_in_scan = 1
// for AC coefficients.
for(int ci=0; ci<cinfo.comps_in_scan; ci++)
{
jpeg_component_info compptr=cinfo.cur_comp_info[ci];
// Initialize DC predictions to 0
entropy.last_dc_val[ci]=0;
// Get table index
int tbl;
if(is_DC_band)
{
if(cinfo.Ah!=0) continue; // DC refinement needs no table
tbl=compptr.dc_tbl_no;
}
else entropy.ac_tbl_no=tbl=compptr.ac_tbl_no;
if(gather_statistics)
{
// Check for invalid table index
// (make_c_derived_tbl does this in the other path)
if(tbl<0||tbl>=NUM_HUFF_TBLS) ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_NO_HUFF_TABLE, tbl);
// Allocate and zero the statistics tables
// Note that jpeg_gen_optimal_table expects 257 entries in each table!
if(entropy.count_ptrs[tbl]==null)
{
try
{
entropy.count_ptrs[tbl]=new int[257];
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
}
else
{
for(int i=0; i<257; i++) entropy.count_ptrs[tbl][i]=0;
}
}
else
{
// Compute derived values for Huffman table
// We may do this more than once for a table, but it's not expensive
jpeg_make_c_derived_tbl(cinfo, is_DC_band, tbl, ref entropy.derived_tbls[tbl]);
}
}
// Initialize AC stuff
entropy.EOBRUN=0;
entropy.BE=0;
// Initialize bit buffer to empty
entropy.put_buffer=0;
entropy.put_bits=0;
// Initialize restart stuff
entropy.restarts_to_go=cinfo.restart_interval;
entropy.next_restart_num=0;
}
// Outputting bytes to the file.
// NB: these must be called only when actually outputting,
// that is, entropy.gather_statistics == false.
// Empty the output buffer; we do not support suspension in this module.
static void dump_buffer(phuff_entropy_encoder entropy)
{
jpeg_destination_mgr dest=entropy.cinfo.dest;
if(!dest.empty_output_buffer(entropy.cinfo)) ERREXIT(entropy.cinfo, J_MESSAGE_CODE.JERR_CANT_SUSPEND);
// After a successful buffer dump, must reset buffer pointers
entropy.output_bytes=dest.output_bytes;
entropy.next_output_byte=dest.next_output_byte;
entropy.free_in_buffer=dest.free_in_buffer;
}
// Outputting bits to the file
// Only the right 24 bits of put_buffer are used; the valid bits are
// left-justified in this part. At most 16 bits can be passed to emit_bits
// in one call, and we never retain more than 7 bits in put_buffer
// between calls, so 24 bits are sufficient.
// Emit some bits, unless we are in gather mode
static void emit_bits(phuff_entropy_encoder entropy, uint code, int size)
{
// This routine is heavily used, so it's worth coding tightly.
int put_buffer=(int)code;
int put_bits=entropy.put_bits;
// if size is 0, caller used an invalid Huffman table entry
if(size==0) ERREXIT(entropy.cinfo, J_MESSAGE_CODE.JERR_HUFF_MISSING_CODE);
if(entropy.gather_statistics) return; // do nothing if we're only getting stats
put_buffer&=(1<<size)-1; // mask off any extra bits in code
put_bits+=size; // new number of bits in buffer
put_buffer<<=24-put_bits; // align incoming bits
put_buffer|=entropy.put_buffer; // and merge with old buffer contents
while(put_bits>=8)
{
byte c=(byte)((put_buffer>>16)&0xFF);
//was emit_byte(entropy, c);
entropy.output_bytes[entropy.next_output_byte++]=c;
entropy.free_in_buffer--;
if(entropy.free_in_buffer==0) dump_buffer(entropy);
if(c==0xFF)
{ // need to stuff a zero byte?
//was emit_byte(entropy, 0);
entropy.output_bytes[entropy.next_output_byte++]=0;
entropy.free_in_buffer--;
if(entropy.free_in_buffer==0) dump_buffer(entropy);
}
put_buffer<<=8;
put_bits-=8;
}
entropy.put_buffer=put_buffer; // update variables
entropy.put_bits=put_bits;
}
static void flush_bits(phuff_entropy_encoder entropy)
{
emit_bits(entropy, 0x7F, 7); // fill any partial byte with ones
entropy.put_buffer=0; // and reset bit-buffer to empty
entropy.put_bits=0;
}
// Emit (or just count) a Huffman symbol.
static void emit_symbol(phuff_entropy_encoder entropy, int tbl_no, int symbol)
{
if(entropy.gather_statistics) entropy.count_ptrs[tbl_no][symbol]++;
else
{
c_derived_tbl tbl=entropy.derived_tbls[tbl_no];
emit_bits(entropy, tbl.ehufco[symbol], tbl.ehufsi[symbol]);
}
}
// Emit bits from a correction bit buffer.
static void emit_buffered_bits(phuff_entropy_encoder entropy, byte[] buf, uint bufstart, uint nbits)
{
if(entropy.gather_statistics) return; // no real work
while(nbits>0)
{
emit_bits(entropy, buf[bufstart++], 1);
nbits--;
}
}
// Emit any pending EOBRUN symbol.
static void emit_eobrun(phuff_entropy_encoder entropy)
{
if(entropy.EOBRUN<=0) return;
// if there is any pending EOBRUN
int temp=(int)entropy.EOBRUN;
int nbits=0;
while((temp>>=1)!=0) nbits++;
// safety check: shouldn't happen given limited correction-bit buffer
if(nbits>14) ERREXIT(entropy.cinfo, J_MESSAGE_CODE.JERR_HUFF_MISSING_CODE);
emit_symbol(entropy, entropy.ac_tbl_no, nbits<<4);
if(nbits!=0) emit_bits(entropy, entropy.EOBRUN, nbits);
entropy.EOBRUN=0;
// Emit any buffered correction bits
emit_buffered_bits(entropy, entropy.bit_buffer, 0, entropy.BE);
entropy.BE=0;
}
// Emit a restart marker & resynchronize predictions.
static void emit_restart(phuff_entropy_encoder entropy, int restart_num)
{
emit_eobrun(entropy);
if(!entropy.gather_statistics)
{
flush_bits(entropy);
//was emit_byte(entropy, 0xFF);
entropy.output_bytes[entropy.next_output_byte++]=0xFF;
entropy.free_in_buffer--;
if(entropy.free_in_buffer==0) dump_buffer(entropy);
//was emit_byte(entropy, JPEG_RST0+restart_num);
entropy.output_bytes[entropy.next_output_byte++]=(byte)(JPEG_RST0+restart_num);
entropy.free_in_buffer--;
if(entropy.free_in_buffer==0) dump_buffer(entropy);
}
if(entropy.cinfo.Ss==0)
{
// Re-initialize DC predictions to 0
for(int ci=0; ci<entropy.cinfo.comps_in_scan; ci++) entropy.last_dc_val[ci]=0;
}
else
{
// Re-initialize all AC-related fields to 0
entropy.EOBRUN=0;
entropy.BE=0;
}
}
// MCU encoding for DC initial scan (either spectral selection,
// or first pass of successive approximation).
static bool encode_mcu_DC_first_phuff(jpeg_compress cinfo, short[][] MCU_data)
{
jpeg_lossy_c_codec lossyc=(jpeg_lossy_c_codec)cinfo.coef;
phuff_entropy_encoder entropy=(phuff_entropy_encoder)lossyc.entropy_private;
int Al=cinfo.Al;
entropy.output_bytes=cinfo.dest.output_bytes;
entropy.next_output_byte=cinfo.dest.next_output_byte;
entropy.free_in_buffer=cinfo.dest.free_in_buffer;
// Emit restart marker if needed
if(cinfo.restart_interval!=0)
{
if(entropy.restarts_to_go==0) emit_restart(entropy, entropy.next_restart_num);
}
// Encode the MCU data blocks
for(int blkn=0; blkn<cinfo.block_in_MCU; blkn++)
{
short[] block=MCU_data[blkn];
int ci=cinfo.MCU_membership[blkn];
jpeg_component_info compptr=cinfo.cur_comp_info[ci];
// Compute the DC value after the required point transform by Al.
// This is simply an arithmetic right shift.
int temp2=(int)block[0]>>Al;
// DC differences are figured on the point-transformed values.
int temp=temp2-entropy.last_dc_val[ci];
entropy.last_dc_val[ci]=temp2;
// Encode the DC coefficient difference per section G.1.2.1
temp2=temp;
if(temp<0)
{
temp=-temp; // temp is abs value of input
// For a negative input, want temp2 = bitwise complement of abs(input)
// This code assumes we are on a two's complement machine
temp2--;
}
// Find the number of bits needed for the magnitude of the coefficient
int nbits=0;
while(temp!=0)
{
nbits++;
temp>>=1;
}
// Check for out-of-range coefficient values.
// Since we're encoding a difference, the range limit is twice as much.
if(nbits>MAX_COEF_BITS+1) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_DCT_COEF);
// Count/emit the Huffman-coded symbol for the number of bits
emit_symbol(entropy, compptr.dc_tbl_no, nbits);
// Emit that number of bits of the value, if positive,
// or the complement of its magnitude, if negative.
if(nbits!=0) emit_bits(entropy, (uint)temp2, nbits); // emit_bits rejects calls with size 0
}
cinfo.dest.output_bytes=entropy.output_bytes;
cinfo.dest.next_output_byte=entropy.next_output_byte;
cinfo.dest.free_in_buffer=entropy.free_in_buffer;
// Update restart-interval state too
if(cinfo.restart_interval!=0)
{
if(entropy.restarts_to_go==0)
{
entropy.restarts_to_go=cinfo.restart_interval;
entropy.next_restart_num++;
entropy.next_restart_num&=7;
}
entropy.restarts_to_go--;
}
return true;
}
// MCU encoding for AC initial scan (either spectral selection,
// or first pass of successive approximation).
static bool encode_mcu_AC_first_phuff(jpeg_compress cinfo, short[][] MCU_data)
{
jpeg_lossy_c_codec lossyc=(jpeg_lossy_c_codec)cinfo.coef;
phuff_entropy_encoder entropy=(phuff_entropy_encoder)lossyc.entropy_private;
int Se=cinfo.Se;
int Al=cinfo.Al;
entropy.output_bytes=cinfo.dest.output_bytes;
entropy.next_output_byte=cinfo.dest.next_output_byte;
entropy.free_in_buffer=cinfo.dest.free_in_buffer;
// Emit restart marker if needed
if(cinfo.restart_interval!=0)
{
if(entropy.restarts_to_go==0) emit_restart(entropy, entropy.next_restart_num);
}
// Encode the MCU data block
short[] block=MCU_data[0];
// Encode the AC coefficients per section G.1.2.2, fig. G.3
int r=0; // r = run length of zeros
for(int k=cinfo.Ss; k<=Se; k++)
{
int temp=block[jpeg_natural_order[k]];
if(temp==0)
{
r++;
continue;
}
// 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; so the code is
// interwoven with finding the abs value (temp) and output bits (temp2).
int temp2;
if(temp<0)
{
temp=-temp; // temp is abs value of input
temp>>=Al; // apply the point transform
// For a negative coef, want temp2 = bitwise complement of abs(coef)
temp2=~temp;
}
else
{
temp>>=Al; // apply the point transform
temp2=temp;
}
// Watch out for case that nonzero coef is zero after point transform
if(temp==0)
{
r++;
continue;
}
// Emit any pending EOBRUN
if(entropy.EOBRUN>0) emit_eobrun(entropy);
// if run length > 15, must emit special run-length-16 codes (0xF0)
while(r>15)
{
emit_symbol(entropy, entropy.ac_tbl_no, 0xF0);
r-=16;
}
// Find the number of bits needed for the magnitude of the coefficient
int nbits=1; // there must be at least one 1 bit
while((temp>>=1)!=0) nbits++;
// Check for out-of-range coefficient values
if(nbits>MAX_COEF_BITS) ERREXIT(cinfo, J_MESSAGE_CODE.JERR_BAD_DCT_COEF);
// Count/emit Huffman symbol for run length / number of bits
emit_symbol(entropy, entropy.ac_tbl_no, (r<<4)+nbits);
// Emit that number of bits of the value, if positive,
// or the complement of its magnitude, if negative.
emit_bits(entropy, (uint)temp2, nbits);
r=0; // reset zero run length
}
if(r>0) // If there are trailing zeroes,
{
entropy.EOBRUN++; // count an EOB
if(entropy.EOBRUN==0x7FFF) emit_eobrun(entropy); // force it out to avoid overflow
}
cinfo.dest.output_bytes=entropy.output_bytes;
cinfo.dest.next_output_byte=entropy.next_output_byte;
cinfo.dest.free_in_buffer=entropy.free_in_buffer;
// Update restart-interval state too
if(cinfo.restart_interval!=0)
{
if(entropy.restarts_to_go==0)
{
entropy.restarts_to_go=cinfo.restart_interval;
entropy.next_restart_num++;
entropy.next_restart_num&=7;
}
entropy.restarts_to_go--;
}
return true;
}
// MCU encoding 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.
static bool encode_mcu_DC_refine_phuff(jpeg_compress cinfo, short[][] MCU_data)
{
jpeg_lossy_c_codec lossyc=(jpeg_lossy_c_codec)cinfo.coef;
phuff_entropy_encoder entropy=(phuff_entropy_encoder)lossyc.entropy_private;
int Al=cinfo.Al;
entropy.output_bytes=cinfo.dest.output_bytes;
entropy.next_output_byte=cinfo.dest.next_output_byte;
entropy.free_in_buffer=cinfo.dest.free_in_buffer;
// Emit restart marker if needed
if(cinfo.restart_interval!=0)
{
if(entropy.restarts_to_go==0) emit_restart(entropy, entropy.next_restart_num);
}
// Encode the MCU data blocks
for(int blkn=0; blkn<cinfo.block_in_MCU; blkn++)
{
short[] block=MCU_data[blkn];
// We simply emit the Al'th bit of the DC coefficient value.
int temp=block[0];
emit_bits(entropy, (uint)(temp>>Al), 1);
}
cinfo.dest.output_bytes=entropy.output_bytes;
cinfo.dest.next_output_byte=entropy.next_output_byte;
cinfo.dest.free_in_buffer=entropy.free_in_buffer;
// Update restart-interval state too
if(cinfo.restart_interval!=0)
{
if(entropy.restarts_to_go==0)
{
entropy.restarts_to_go=cinfo.restart_interval;
entropy.next_restart_num++;
entropy.next_restart_num&=7;
}
entropy.restarts_to_go--;
}
return true;
}
// MCU encoding for AC successive approximation refinement scan.
static bool encode_mcu_AC_refine_phuff(jpeg_compress cinfo, short[][] MCU_data)
{
jpeg_lossy_c_codec lossyc=(jpeg_lossy_c_codec)cinfo.coef;
phuff_entropy_encoder entropy=(phuff_entropy_encoder)lossyc.entropy_private;
int r;
byte[] BR_buffer;
uint BR;
int Se=cinfo.Se;
int Al=cinfo.Al;
int[] absvalues=new int[DCTSIZE2];
entropy.output_bytes=cinfo.dest.output_bytes;
entropy.next_output_byte=cinfo.dest.next_output_byte;
entropy.free_in_buffer=cinfo.dest.free_in_buffer;
// Emit restart marker if needed
if(cinfo.restart_interval!=0)
{
if(entropy.restarts_to_go==0) emit_restart(entropy, entropy.next_restart_num);
}
// Encode the MCU data block
short[] block=MCU_data[0];
// It is convenient to make a pre-pass to determine the transformed
// coefficients' absolute values and the EOB position.
int EOB=0;
int k;
for(k=cinfo.Ss; k<=Se; k++)
{
int temp=block[jpeg_natural_order[k]];
// 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(temp<0) temp=-temp; // temp is abs value of input
temp>>=Al; // apply the point transform
absvalues[k]=temp; // save abs value for main pass
if(temp==1) EOB=k; // EOB = index of last newly-nonzero coef
}
// Encode the AC coefficients per section G.1.2.3, fig. G.7
r=0; // r = run length of zeros
BR=0; // BR = count of buffered bits added now
BR_buffer=entropy.bit_buffer; // Append bits to buffer
uint BR_buffer_ind=entropy.BE;
for(k=cinfo.Ss; k<=Se; k++)
{
int temp=absvalues[k];
if(temp==0)
{
r++;
continue;
}
// Emit any required ZRLs, but not if they can be folded into EOB
while(r>15&&k<=EOB)
{
// emit any pending EOBRUN and the BE correction bits
emit_eobrun(entropy);
// Emit ZRL
emit_symbol(entropy, entropy.ac_tbl_no, 0xF0);
r-=16;
// Emit buffered correction bits that must be associated with ZRL
emit_buffered_bits(entropy, BR_buffer, BR_buffer_ind, BR);
BR_buffer=entropy.bit_buffer; // BE bits are gone now
BR_buffer_ind=0;
BR=0;
}
// If the coef was previously nonzero, it only needs a correction bit.
// NOTE: a straight translation of the spec's figure G.7 would suggest
// that we also need to test r > 15. But if r > 15, we can only get here
// if k > EOB, which implies that this coefficient is not 1.
if(temp>1)
{
// The correction bit is the next bit of the absolute value.
BR_buffer[BR_buffer_ind+BR++]=(byte)(temp&1);
continue;
}
// Emit any pending EOBRUN and the BE correction bits
emit_eobrun(entropy);
// Count/emit Huffman symbol for run length / number of bits
emit_symbol(entropy, entropy.ac_tbl_no, (r<<4)+1);
// Emit output bit for newly-nonzero coef
temp=(block[jpeg_natural_order[k]]<0)?0:1;
emit_bits(entropy, (uint)temp, 1);
// Emit buffered correction bits that must be associated with this code
emit_buffered_bits(entropy, BR_buffer, BR_buffer_ind, BR);
BR_buffer=entropy.bit_buffer; // BE bits are gone now
BR_buffer_ind=0;
BR=0;
r=0; // reset zero run length
}
if(r>0||BR>0) // If there are trailing zeroes,
{
entropy.EOBRUN++; // count an EOB
entropy.BE+=BR; // concat my correction bits to older ones
// We force out the EOB if we risk either:
// 1. overflow of the EOB counter;
// 2. overflow of the correction bit buffer during the next MCU.
if(entropy.EOBRUN==0x7FFF||entropy.BE>(MAX_CORR_BITS-DCTSIZE2+1)) emit_eobrun(entropy);
}
cinfo.dest.output_bytes=entropy.output_bytes;
cinfo.dest.next_output_byte=entropy.next_output_byte;
cinfo.dest.free_in_buffer=entropy.free_in_buffer;
// Update restart-interval state too
if(cinfo.restart_interval!=0)
{
if(entropy.restarts_to_go==0)
{
entropy.restarts_to_go=cinfo.restart_interval;
entropy.next_restart_num++;
entropy.next_restart_num&=7;
}
entropy.restarts_to_go--;
}
return true;
}
// Finish up at the end of a Huffman-compressed progressive scan.
static void finish_pass_phuff(jpeg_compress cinfo)
{
jpeg_lossy_c_codec lossyc=(jpeg_lossy_c_codec)cinfo.coef;
phuff_entropy_encoder entropy=(phuff_entropy_encoder)lossyc.entropy_private;
entropy.output_bytes=cinfo.dest.output_bytes;
entropy.next_output_byte=cinfo.dest.next_output_byte;
entropy.free_in_buffer=cinfo.dest.free_in_buffer;
// Flush out any buffered data
emit_eobrun(entropy);
flush_bits(entropy);
cinfo.dest.output_bytes=entropy.output_bytes;
cinfo.dest.next_output_byte=entropy.next_output_byte;
cinfo.dest.free_in_buffer=entropy.free_in_buffer;
}
// Finish up a statistics-gathering pass and create the new Huffman tables.
static void finish_pass_gather_phuff(jpeg_compress cinfo)
{
jpeg_lossy_c_codec lossyc=(jpeg_lossy_c_codec)cinfo.coef;
phuff_entropy_encoder entropy=(phuff_entropy_encoder)lossyc.entropy_private;
// Flush out buffered data (all we care about is counting the EOB symbol)
emit_eobrun(entropy);
bool is_DC_band=(cinfo.Ss==0);
// It's important not to apply jpeg_gen_optimal_table more than once
// per table, because it clobbers the input frequency counts!
bool[] did=new bool[NUM_HUFF_TBLS];
for(int ci=0; ci<cinfo.comps_in_scan; ci++)
{
jpeg_component_info compptr=cinfo.cur_comp_info[ci];
int tbl;
if(is_DC_band)
{
if(cinfo.Ah!=0) continue; // DC refinement needs no table
tbl=compptr.dc_tbl_no;
}
else
{
tbl=compptr.ac_tbl_no;
}
if(!did[tbl])
{
if(is_DC_band)
{
if(cinfo.dc_huff_tbl_ptrs[tbl]==null) cinfo.dc_huff_tbl_ptrs[tbl]=jpeg_alloc_huff_table(cinfo);
jpeg_gen_optimal_table(cinfo, cinfo.dc_huff_tbl_ptrs[tbl], entropy.count_ptrs[tbl]);
}
else
{
if(cinfo.ac_huff_tbl_ptrs[tbl]==null) cinfo.ac_huff_tbl_ptrs[tbl]=jpeg_alloc_huff_table(cinfo);
jpeg_gen_optimal_table(cinfo, cinfo.ac_huff_tbl_ptrs[tbl], entropy.count_ptrs[tbl]);
}
did[tbl]=true;
}
}
}
static bool need_optimization_pass_phuff(jpeg_compress cinfo)
{
return (cinfo.Ss!=0||cinfo.Ah==0);
}
// Module initialization routine for progressive Huffman entropy encoding.
static void jinit_phuff_encoder(jpeg_compress cinfo)
{
jpeg_lossy_c_codec lossyc=(jpeg_lossy_c_codec)cinfo.coef;
phuff_entropy_encoder entropy=null;
try
{
entropy=new phuff_entropy_encoder();
}
catch
{
ERREXIT1(cinfo, J_MESSAGE_CODE.JERR_OUT_OF_MEMORY, 4);
}
lossyc.entropy_private=entropy;
lossyc.entropy_start_pass=start_pass_phuff;
lossyc.need_optimization_pass=need_optimization_pass_phuff;
// Mark tables unallocated
for(int i=0; i<NUM_HUFF_TBLS; i++)
{
entropy.derived_tbls[i]=null;
entropy.count_ptrs[i]=null;
}
entropy.bit_buffer=null; // needed only in AC refinement scan
}
}
}
#endif